U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2018–5131

Federal Lands Greenhouse Gas Emissions 

and Sequestration in the United States: 

Estimates for 2005–14
Cover. South Pass; Oregon, Mormon Pioneer, California, and Pony Express National Historic Trails 

Corridor; Wyoming. Photograph by Bob Wick, Bureau of Land Management, September 16, 2010.
Federal Lands Greenhouse Gas Emissions 

and Sequestration in the United States: 

Estimates for 2005–14

By Matthew D. Merrill, Benjamin M. Sleeter, Philip A. Freeman, Jinxun Liu, 

Peter D. Warwick, and Bradley C. Reed

Scientific Investigations Report 2018–5131

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

RYAN K. ZINKE, Secretary

U.S. Geological Survey

James F. Reilly II, Director

U.S. Geological Survey, Reston, Virginia: 2018

For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, 

natural hazards, and the environment—visit https://www.usgs.gov or call 1–888–ASK–USGS (1–888–275–8747).

For an overview of USGS information products, including maps, imagery, and publications, 

visit https://store.usgs.gov.

Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the 

U.S. Government.

Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials 

as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.

Suggested citation:

Merrill, M.D., Sleeter, B.M., Freeman, P.A., Liu, J., Warwick, P.D., and Reed, B.C., 2018, Federal lands greenhouse 

gas emissions and sequestration in the United States—Estimates for 2005–14: U.S. Geological Survey Scientific 

Investigations Report 2018–5131, 31 p., https://doi.org/10.3133/sir20185131.

ISSN 2328-0328 (online)
iii

Acknowledgments

The estimates of fossil fuel-associated emissions in this report were generated by methods 

that relied heavily on the work of others. Data repositories used and sources of guidance on 

the methodology are extensively cited in the text. Specific acknowledgements are necessary 

for contributors who aided the authors in the interpretation of published materials and provided 

instruction on making the estimates included here. The authors thank the following colleagues 

in the U.S. Department of the Interior: John Hovanec, Robert Kronebusch, and the Data Services 

team of the Office of Natural Resources Revenue; Holli Ensz of the Bureau of Ocean Energy 

Management; and the Bureau of Land Management. The authors also recognize Vincent 

Camobreco, Mausami Desai, Cate Hight, Christopher Sherry, and Melissa Weitz of the U.S. 

Environmental Protection Agency (EPA) for assistance in utilizing their methodology, accessing 

data, and reviewing the manuscript. Thanks are also extended to Allan Kolker of the U.S. 

Geological Survey (USGS) for a helpful review.

The estimates of carbon sequestration in terrestrial ecosystems were derived primarily through 

an analysis of modeling projects led by Zhiliang Zhu of the USGS. Specifically, we acknowledge 

Dave McGuire of the USGS and Hélène Genet of the University of Alaska Fairbanks for their 

work on modeling carbon fluxes in Alaska and Paul Selmants and Jason Sherba of the USGS 

and Christian Giardina of the U.S. Forest Service for their work in Hawaii. Furthermore, we thank 

Paul Selmants of the USGS and Tom Wirth of the EPA for their reviews.

The project’s initial stages benefited greatly from the work of Robin O’Malley of the USGS, who 

organized numerous interagency meetings that lead to valuable data exchange and expertise 

assistance.

v

Contents

Acknowledgments........................................................................................................................................iii

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Fossil Fuel-Associated Emissions of Greenhouse Gases from Federal Lands....................................3

Introduction............................................................................................................................................3

Data Sources.........................................................................................................................................3

Methodology..........................................................................................................................................4

Introduction...................................................................................................................................4

Stationary Combustion Emissions.............................................................................................5

Mobile Combustion Emissions...................................................................................................5

Petroleum and Natural Gas Systems Emissions ....................................................................5

Active Coal Mine Emissions.......................................................................................................5

Abandoned Coal Mine Emissions .............................................................................................5

Exported Fuels Emissions...........................................................................................................6

Results ....................................................................................................................................................6

Uncertainty of Emissions Estimates .........................................................................................8

Precision and Rounding of Emissions Estimates....................................................................8

Terrestrial Ecosystems-Associated Carbon Emissions and Sequestration on 

Federal Lands..................................................................................................................................10

Introduction..........................................................................................................................................10

Data Sources.......................................................................................................................................10

Methodology........................................................................................................................................10

Conterminous United States ....................................................................................................11

Alaska ..........................................................................................................................................12

Hawaii..........................................................................................................................................12

Results ..................................................................................................................................................12

Net Emissions and Sequestration Results...............................................................................................17

Conclusions...................................................................................................................................................19

References Cited..........................................................................................................................................19

Glossary.........................................................................................................................................................22

Appendix 1. Detailed Methods: Fossil Fuel-Associated Emissions of Greenhouse 

Gases from Federal Lands ............................................................................................................24

Appendix 2. Detailed Methods: Terrestrial Ecosystems-Associated Carbon 

Emissions and Sequestration on Federal Lands .......................................................................30
vi

Tables

1. National totals and subtotals for several categories of greenhouse gas

emissions associated with the combustion and extraction of fossil fuels from

U.S. Federal lands in 2014............................................................................................................7

2. National totals for greenhouse gas emissions associated with the

combustion and extraction of fossil fuels from U.S. Federal lands in

2005–14 ...........................................................................................................................................8

3. Explanation of carbon stock and flux terms from the terrestrial ecosystem

sequestration calculations........................................................................................................11

4. Carbon stocks and fluxes for Federal lands in the conterminous 

United States, 2005–14...............................................................................................................13

5. Average annual carbon stocks and fluxes for onshore Federal lands in the

United States, 2005–14...............................................................................................................14

6. Net emissions for Federal lands in the United States, 2005–14..........................................17

1–1. Inputs and sources for the stationary combustion greenhouse gas emissions

estimate........................................................................................................................................25

1–2. Inputs and sources for the mobile sector combustion greenhouse gas

emissions estimate.....................................................................................................................25

1–3. Inputs and sources for the petroleum and natural gas systems greenhouse

gas emissions estimate .............................................................................................................27

1–4. Inputs and sources for the active coal mining greenhouse gas emissions

estimate........................................................................................................................................27

1–5. Inputs and sources for the abandoned coal mine greenhouse gas emissions

estimate........................................................................................................................................27

1–6. Inputs and sources for the exported fuels greenhouse gas emissions estimate............28

Figures

1. Map showing the onshore Federal lands (excluding American Indian and

Tribal lands) and offshore Federal Outer Continental Shelf planning areas

(offshore Pacific and offshore Gulf) included in the emissions and

sequestration estimates ..............................................................................................................2

2. Pie chart showing carbon dioxide emissions associated with the extraction

and combustion of fossil fuels produced from Federal lands in the 10 States

or offshore regions with the highest emissions, 2014 ............................................................9

3. Pie chart showing methane emissions associated with the extraction and

combustion of fossil fuels produced from Federal lands in the 10 States or

offshore regions with the highest emissions, 2014 .................................................................9

4. Graph showing estimates of annual rates of net primary productivity, net

ecosystems productivity, and net biome productivity for the conterminous

United States, 1985–2015...........................................................................................................16
vii

Conversion Factors

Multiply By To obtain

Length

meter (m) 3.281 foot (ft)

kilometer (km) 0.6214 mile (mi)

Area

square meter (m2

) 10.76 square foot (ft2)

hectare (ha) 2.471 acre

Volume

barrel (bbl; petroleum, 

1 barrel=42 gallons)

0.1590 cubic meter (m3

) 

Mass

kilogram (kg) 2.205 pound avoirdupois (lb)

metric ton (t) 1.102 ton, short (2,000 lb)

metric ton (t) 0.9842 ton, long (2,240 lb)

Carbon density

kilogram per square meter 

(kg/m2)

0.2048 pound per square foot (lb/ft2

)
viii

Abbreviations

BLM Bureau of Land Management

CH4 methane

CO2 carbon dioxide

CONUS conterminous United States

DOM dead organic matter

DOS-TEM Dynamic Organic Soil version of the Terrestrial Ecosystem Model

EIA U.S. Energy Information Administration

EPA U.S. Environmental Protection Agency

GPP gross primary productivity

IBIS Integrated Biosphere Simulator

km kilometer

LUCAS Land Use and Carbon Scenario Simulator

LULC land use and land cover

m meter

t CO2 Eq./ha metric tons of carbon dioxide equivalent per hectare

t CO2 Eq./ha/yr metric tons of carbon dioxide equivalent per hectare per year

MMT CO2 Eq. million metric tons of carbon dioxide equivalent

MMT CO2 Eq./yr million metric tons of carbon dioxide equivalent per year

MSHA Mine Safety and Health Administration

N2O nitrous oxide

NBP net biome productivity

NEP net ecosystems productivity

NPP net primary productivity

OCS Outer Continental Shelf

ONRR Office of Natural Resources Revenue

PADUS Protected Areas Database of the United States

Ra autotrophic respiration

Rh heterotrophic respiration

TEC total ecosystem carbon

USDA U.S. Department of Agriculture

USGS U.S. Geological Survey
Federal Lands Greenhouse Gas Emissions and 

Sequestration in the United States: Estimates for 2005–14

By Matthew D. Merrill, Benjamin M. Sleeter, Philip A. Freeman, Jinxun Liu, Peter D. Warwick, and 

Bradley C. Reed

Abstract

In January 2016, the Secretary of the U.S. Department of 

the Interior tasked the U.S. Geological Survey (USGS) with 

producing a publicly available and annually updated database 

of estimated greenhouse gas emissions associated with the 

extraction and use (predominantly some form of combustion) 

of fossil fuels from Federal lands. In response, the USGS has 

produced estimates of the greenhouse gas emissions resulting from the extraction and end-use combustion of fossil 

fuels produced on Federal lands in the United States, as well 

as estimates of ecosystem carbon emissions and sequestration on those lands. American Indian and Tribal lands were 

not included in this analysis. The emissions estimates span 

a 10-year period (2005–14) and are reported for 28 States 

and two offshore areas. Nationwide emissions from fossil 

fuels produced on Federal lands in 2014 were 1,279.0 million 

metric tons of carbon dioxide equivalent (MMT CO2 Eq.) for 

carbon dioxide (CO2), 47.6 MMT CO2 Eq. for methane (CH4), 

and 5.5 MMT CO2 Eq. for nitrous oxide (N2O). Compared 

to 2005, the 2014 totals represent decreases in emissions for 

all three greenhouse gases (decreases of 6.1 percent for CO2, 

10.5 percent for CH4, and 20.3 percent for N2O). Emissions 

from fossil fuels produced on Federal lands represent, on average, 23.7 percent of national emissions for CO2

, 7.3 percent 

for CH4, and 1.5 percent for N2O over the 10 years included in 

this estimate.

In 2005, Federal lands of the conterminous United States 

stored 82,289 MMT CO2 Eq. in terrestrial ecosystems. By 

2014, carbon storage, or sequestration, was estimated at 

83,600 MMT CO2 Eq., representing an increase of 1.6 percent, 

or 1,311 MMT CO2 Eq. Soils stored most of the ecosystem 

carbon (63 percent), followed by live vegetation (26 percent) 

and dead organic matter (11 percent). The rate of net carbon 

uptake in ecosystems ranged from a sink (sequestration) of 

475 million metric tons of carbon dioxide equivalent per year 

(MMT CO2 Eq./yr) to a source (emission) of 51 MMT CO2

Eq./yr because of annual variability in climate and weather, 

rates of land-use and land-cover change, and wildfire frequency, among other factors. At the national level, the USGS 

estimates that terrestrial ecosystems (forests, grasslands, 

and shrublands) on Federal lands sequestered an average of 

195 MMT CO2 Eq./yr between 2005 and 2014, offsetting 

approximately 15 percent of the CO2 emissions resulting from 

the extraction of fossil fuels on Federal lands and their end-use 

combustion.

The USGS estimates presented in this report represent 

a first-of-its-kind accounting for the emissions resulting 

from fossil fuel extraction on Federal lands and the end-use 

combustion of those fuels, as well as for the sequestration of 

carbon in terrestrial ecosystems on Federal lands. The net CO2

emissions estimate, which is the difference between the emitted and sequestered CO2

, provides an informative combined 

result describing the emissions (fossil fuel extraction and enduse combustion) associated with a State’s Federal lands and 

sequestration on those same lands. The estimates included in 

this report can provide context for future energy decisions, as 

well as a basis to track change in the future.

Introduction

In January 2016, the Secretary of the U.S. Department of 

the Interior tasked the U.S. Geological Survey (USGS) with 

producing a publicly available and annually updated database 

of estimated greenhouse gas emissions associated with the 

extraction and use (predominantly some form of combustion) of fossil fuels from Federal lands (fig. 1). In response, 

the USGS began a study of greenhouse gas emissions and 

carbon sequestration on Federal lands in the United States; the 

study produced the requested estimates for 2005–14. National 

estimates of greenhouse gas emissions are published by the 

U.S. Environmental Protection Agency (EPA), but these estimates do not report emissions from Federal lands specifically. 

Therefore, this USGS effort relies heavily on the established 

methods used by the EPA but uses State-level data specific to 

emissions associated with Federal lands.

Fossil fuel extraction and combustion emit greenhouse 

gases. Industrial injection of greenhouse gases into the subsurface for enhanced hydrocarbon production or for greenhouse 

gas storage are forms of sequestration. Industrial sequestration 

is not included in the estimate because of the small magnitude 
2 Federal Lands Greenhouse Gas Emissions and Sequestration in the United States: Estimates for 2005–14

!

! !

!

!

!

!!

!

!

!

! !

!

!

!

! !

! !

!

!

!

!

!!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

! !!

!

!

!

!

!

!

!

! !

!

!

! ! !

!

!

! ! !

!

!

!

!

!

!

! ! ! !

!

! !

!

! ! !

!

!

!

!

!

!

! !

! !

!

!

!

! !

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

! !

!

!

!

!

!

!

!! !

!

! !

!! ! !

!

!

!

!

!

!

!

!!

! !

!

!

!

!

!

!

! !

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! ! !

!

!

!

!!

!

!

!

!

!

!

!

!

! !

!

!

! !

!

! !

!

!

!

!

! !

! ! ! ! !

!

!

!

!

!

!

!

!

!

!

!

!

!! !

!!

! !

!

!

!

!

! !

!

!

!

!

!

!

! !

!

!

! !

! !

! !

! !

!

!

!

!

! ! !

!

! !

!

! !

!

! ! !

!

!

!

!

!

!!

!

!

!

!

!

! !

!

!

! !

!

!

!

!

! ! ! !

!

!

! !

! !

! !

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

! !

!

! !

!

!

! ! ! !

!

!

!

!

! ! !

! !

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

! !!

!

!

! !

!

!

!

!

!

!

!

! !

!

!! !

!

!

!

!

!

!

!

! !

! ! !

!

! !

!

!

! !!

!

!

! ! !

!

! !

!

!

!

!

! !

! !

!

!

!

!

! !

!

! !!

!

!

! !

! ! ! !

!

!

!

!!

!

!

!

! !

!

!

!

!

!

!

!

!

!

! !

!

!

!

! !

! ! !

!

!

!

!

!

!

!

!

!!

!

!

!

! !

!

! !

!

!

!

!

! !

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

! !

! !

!

!

!

!

!

! !

!

! !

!

!

!

!

! ! !

! !

!

!

!

!

!

!

!

!!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

! ! !

!

!

!

!

!

! !

!

! ! !

!

! !

!

! !

!

!

!

! !

!

!

!

! !

!

!

!

! !

! ! !

!

!

!

!

! !

!

!

!

! !

!

!

! !

! !

! !

!

!

! !!

!

!

!

! !

!

!

!

! !

!

!

!

! !

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

! ! !

! !

! !

!

!

!

!

!

!

!

!

!

!

!!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

! ! ! !

!

!

!

!

! ! !!

!

!!

! !

!

! !

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

! !

! !

!

!

! !

!

!

!

!

! !

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

! ! ! !

!

!

!

! !

!

!

! !

!!

!

!!

! !

!

!

! !

!

!

!

!

!

!

!

!

!

! !

!

!

!

! !

!

!

! !

!

! ! !

!

!

!

!

!

!

!

!

!!

!

!

!

!

!!

!

! !

! !

!

!

!

!

!

!

!

! !

! !!

!

!

!

! !

!

! !

!

!

!

!

! ! ! ! ! !

!

!

!!

! !

!

!

!

!

!

!

!

!

!

!

!

! ! ! !

!

! ! !

!

!

!

! !

!

!

!

!

!

!

!

!

!

!!

!

!

! !

!

! !

!

!

!

!

!

!

!!

!

!

! ! !

!

! ! ! !!

!

! !

!

!

!!

!

!

!!

! ! !

! !

!

! !

! !

! !

!

!

!

!

!

!

!

!

!

! !

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! ! ! !

!

!

!

!

!

!

!

!!

!

!

! !

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

! ! ! !

!

!

! ! !!

!

! !

!

!

!

! !

!

!

! !

!

!

!

!

!

!

!

!

!

!

! !

!

!! !

!

!!

!

! !

! ! !

!

!

!

! !

! !

!

!

!

!

!

!

!

!

!

! ! !

!

!

!

!!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

! ! !

!

! !

!

!

! !

!

!

!

! !

! !

!

!! ! !!

! ! !

!

!

!

!

!

!

! !!

!

! !

! !

!

!

! ! !

!

! !

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

! !

!

!

!

!

! !

!

!

!

!

! !

!

!

!

! !

!

!

! !! !

! !

! !

!

!

!

!

! ! !

! ! !

!

!

! !

!

!

!

!

!

! !!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

! !

! ! !

!

! !

!

!

!

!

!! !!

! !

! !

! !

!

! !

!

! !

!

!

! !

!

!

!

!

!

! !

! ! !

!

!

! ! !

!

!

!

!

!

! !

!

!!

!

! !

!

! !!!

!

!

!

!

!

! ! !! !! !

!!

!

!

! !

!

! !

!

! !

!

! ! !

!

!

!

!

!

!

! ! ! !!

!

!

! !

!! ! !

!

!

!

!

!!

!!

!

!

!

!

!

!

!

!

! !

! !

!

! !

!!

!

!

! ! !

!

!

!

!

! ! !

! ! !

!

! !

!

!

!

!

! !

!

!

!

!

!! ! ! ! !!

!

! !

!

!

!

!

! !

!

!

!

! !

!

! !

!

!

! !

!!

! !

!

!

!

!

!

!

!

!

!

!! !!! ! !

! !

!

!

!

!

!

!

!

!

!

!

!

!

! !!

!!

!

!

!

!

! !

!

!

!

! !

!!

! !

! !

! !

!

! !!

! !

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

! !

!

!

!

! !!

!

!

!

!

!

!

!!

! !

! ! !

!

!

! ! !

!

!

! !

!

!

!

!

!

!

!

!

!

!! !!

!!

!!!

!

!

!

!

!

! ! !

!

!

!!!! !

!

!!

!!!!!

!

!

!! !

!

! !

!

!!

!

!

!

!

!

!

!!

!!

!

!!

!

!

!

!

!!

!

!

!! !!

! !

!

!

!

!

!!! ! ! !

!

!

! ! ! !

!

! !

!

!

!

!

!!

! !

!

!

!!

!

! !

!

!!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!! ! !

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!!

! !

!

!

!!

!

!

!!

!

!

!

!!

!

!

!!

!

!

!!

!

! ! !

!

!

! !

!

!

!

!

!

!

!

! ! ! !

!

!

! !

!!!

!!

!

!

!

!

! !

!

!

!

!

!

! !

!

!

!

!

!

!

!

! !!!!!!! !! !

!

! !

!

!

!

!!! !!

!

!

!

!

!!! !!!

!!

!

!!

!!

!!!!

!

! !

!

!

!

!

!

!!!!

!!

! !!

!! !

!! ! !! !

!

!

! !! ! !! !

!!

!

! !!

!!! ! ! ! !! !

! ! !!

!!

!

! !

! !!

!!

!!!!!

!

! !

!!!

!!

!!

!

!

! !! !

!! !!

!

!

! !

!!

! !!!

! !! !! !

!

!

!

! !

!

!

!!

!

! !

! !

!

!

!

! !

!

!

! !!

!

!

!

!

!

! !

!

! !

!!

! !

! ! ! !

! !

! ! !

!! !

! ! !

!

!

!!

! !!

!

!

!

! ! !

!

!

!

!

! !

!

! !

!!

! ! !

!

!!

! !

!!

! !!! !

!

! !

!

!

!

!! ! !

!

!

!

!

!

! !

!!

!

! !

!!

!

!

! ! !

!

! !

!

!

!

! !

!

!! !

!

!

!

! !

!!

!

!

!

!

!! !

!

!! ! ! !

!

!!!

!

!!!

!!

!! !!!

!!

!

!

! ! ! !

! !

!

! ! !

!

!!

!

!

!

!!

! !

!! !!!

!!

! !

!! !!!

!

!!

!

!

!!

!

!!

!

!

!

! !

!

!

!

!

!

!

!

! !!

!

!

!

!!

! !

!

!

! ! ! !! ! ! !!!

!

!

!!!

!!!

!!

!! !

!

!

!

! !

!

!

!

!

!

! !

!!!!!

!

! !

!! !

!!

!

!! !

!! !!! !

!

!

! !

! ! ! !

!

! ! !

!

!!

!

!!

!

! !!

!

!

! ! ! !!!!

!

!

!

! ! !! ! !

!

!

! !

!!

!

!!

!!!

!

!

! !!! !!!!! !!! ! ! !!

!!!!!!

!!

!!! !

! !! !!!

!

! !!!! !! ! ! ! ! ! !!!!!

!! !!

!!! !

! !!

! !! ! ! !! ! !!!

!

!!!

!

! !!

!

! !!!!!!

!

!! !

!

! !

!

! ! !

!!!!

! !

!

!

! !

!

! !

!

!!

!

!

!

!

!

!

!

!

! !

!

! !

!

! !

!

! !!

!

!

!

!!

!

!!

!!

!

!

! ! ! !

!

! !!!

!!

!

!

!

!

!

! !

!

!!

!

!

!

!

!

! !

!

! !

!

!

! !

!

!

!

! ! ! !

!

! !

!!

!

!

!

!!

!!

!

!

!

!!

!

!

!

!

!

!

!

!

!

!

! ! !

! !

!

!

!!

!

!! !!

!

!!

! !

!

!! !

!

!

! !

! !

!

!

! !! !

!

!

!

!

!!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

! !

! ! ! !

!

!

!!

!

!

!

!

! !

!

!

!

!

! !

!

! !

!!

!

!

!

!

!

!

! ! ! ! !

! !

!

!

!

!

!

!

!

!

! !

!

! !

!

! !

!

!

!

!

!

! ! !

! !

!

!

!

!

!

!

!!

!

!! !

!

!

! !

!

!

!

!

!

!!

!

!

!!!!

!

!

!

!

! !! ! !

!

!

!

!

!

!

! !

!

!

!

!

!

! !

!

! ! !

! !

! !

! !

!

! !

!

!

!!!

!

! ! !

!

!

!

! !

! !

!

! !

!

!

! !

! !

!

! !

! !

! !

!

!

!

!

! !

! !

!

!

!

!

!

!

!

!! !

!!!

!

!

! !

! !

!!

!

!! !!

!

!

!

! ! ! ! !

!!

! !

!

!

!

! !

!! !

! !! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

! !

! !

!

!

! !! ! !

! !

!

!

!

!

!

!

!

!

!

!!

!

!

! ! ! ! !!

!

! !!! !

!!!

!

! !

! !

!

!

!

!

! ! ! !

!

! !

!

!

!

!

!

!

! !

! !!

!

!

!

! ! !

!

!

! !

!

!

!

!

! !

!! !

!

!

!

!

!

!

!

!! ! !

!

!

!

! !

!!

!

!

!

! !

!

! !

! ! !

!

! !

!

!

!

!

!

!

!

!

!!

!

!

! !

!

! ! ! !

! ! !

!!

! !

! ! ! !

! !

!

!

!

! ! ! !

!!

! !

! !

!

! ! !

!

!

! !

!

!

!

!

! !

!

! ! !!

!

! !

!

! !

!

!

!

!

! !

!

! !

!

! !

!

!

!! !

!

!

! !

!

!

!

!

!

! ! ! !!

!!

!

! !

! !

!

! !

!

!

!

!

!

!

!

!

! ! ! !

!

!

!

!! !

!

!

!

!

! ! !

!

! ! ! ! !! !

!

!

! !

!

!

!

! ! ! !

!

!

!

!

!

!

!

! !

! ! !

!!

!

!

!

!!

! !!

!

!

!

!

!!

! !

! !

!

! !

!

! !

!

! !

!

!!! !

!

!

!

!

!

!

! !

!

!

!

! !

!

! !!

!! !

!

!

!

!

!

!

!

!!

!!

!

!

!

!

! !

!!

!

! ! !

!

!

! !

! ! ! ! !

! !

!

!

! !

! !

!

!

!

!

! !

!

!

! !

!

!

! !

!

!

!

!

!

! !

!

!

!

! ! !

!

! !

!

!

! !!

!

!

!

! !

!

! ! !

! ! !

!

!

! ! ! !

!

!

!

!

! !

!

!

!

!

! !

!

! !

! !

!

!

! !!

!

!

! ! ! ! ! ! !

! !

!

!

!

!!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

! ! ! !

!

!

!

!

! !

! ! !

! !

!!

! !

!

!

!

!

!

!

!

! ! !

!

!!

!

!

! !

!

!

!

!

!

!

!

!

!

!

! !

! !

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

! !

!

!!

!

!

! !

!

!

! !

!

!

!

!

!

!

! !! ! ! ! !

!

!

! !

! ! ! !

!

!

!

!!

!!

!

!

!!

!

!

!

!

!

!

! !!

!

!

!

!

!

! !

!

! ! !!

!

!

!

!

!!

!

!

!

! ! !

!

! !

!

!

!

!

!

! !

!

!! ! !

! !

!

! ! !!

!

!!!

!

!

!

!!

!

!

! ! !

! ! !

! !

!

!

! !! !

!

!

!

!

!

!

!

!

! !

!

!!

!

!

!

!

!

!

!!!

!!

!

!

!

! !

! !

!

!

!

!

!

! !

!

! !

! ! !

!

!

! !

!

!

! !

!

!

!

!

!

!

!

!!

! !

!

!

! !

!

!

!

!

!

!!!!!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!!

! !

!

! ! !

! !

!

!

!

!

!

!

! !

!

!

!!!

! !

!

!

!

!

!

! ! !

!

!

!

! !

!

!

!

! !

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

! !!

!

!

! !

!

! ! !

!

! ! !

!

!

!

!

!

!!

!!

!

!

!

!! ! ! ! !

!

!

! !! !

!

!

!

!

! !!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!!!!

!!

! !

!!

!

!

!

!

!

!!

!

! ! ! !

!

! !!!

!! ! !

! !!

!

!

! !!

!

! !

!

! !

!

!

!

!

!

!

! !

!

!

! ! ! !

!

! !

!

!

!

!

!

!!! ! !

!

!!

!

!

!

! ! !

!

!!

! ! !

!

! ! !

!

!

!

! ! !

!!

!!

! !

!

!

!

!

!

! ! !

!

! !

!

!

!

!

! ! ! !

!

!

! !

! !!

! !

!!

!

!

! !

!

! ! !

!

!

!

!

!

! !

!

!

!

!!

! !

!

!

!

!! !

!!

!

! !

! !!

!

! ! !

!

!!

!

!

!

!

!!

!

!

!

!!

!

!

!

!

!

!

!

!

!

! !

!

!

!! !

!

!

!

!

!

!!

! !

!

!!!!!

!

!

! !! ! !

! !

!

!

!

!

!

!

!

! ! ! ! !

!

!

!

!

!!!

!

!

!

!!

!

!

!!!

!

!

!

!

!

!

! !!

!

!

! !

!

!! !

!

!!

!

!

! ! ! !!!

!! !

!

!

!

!!!

! !

!

!

!

!

!

!

!!

!

!!

!

!

!

!

!

! ! ! !

!

!

!

!

!

!

!

!

!

! !

!

! !

!

!!

!

!

!

! !

!

!!

!

! ! !

!

!!

!

!

!

! !

!

! !

! ! !

! ! !!

!

!

!

!

!!

!

!

!! !

! !

!

!

! !

! ! ! !

! !

!!

!!

!!!!

!! !

!

! ! !

!

!

!

! !

!

!

!!

!

!

!

!

!

!!

!

!

!

!

!

! !

!

!

!

! ! !

! ! !

!

!

!

! !

!

!

!

!

!

! !

!

!

!

!

!

!

! !!!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!!

!

!

!!

!

!

!!

!

!

!!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!!

!

!

! !

!

!

!!

!

!

!

! !

!

!

! !

!

!

! !

!

! ! !

!

!

!!

!!!

!

!

!

!!

!

!

!

! !

!!

!! ! ! !

!

!

!!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!! !

!

! !

!

!

!

!

!

!

!!

!

!

!

!

!

!

! !

! !

! !

! !

!

!

!

! !

!!

!

! !!!!

!

! !

! !

! !!

! ! !

!

!

!! !

!

!

! ! !!

!

!

!

!

!

! !

!

!

!

!

!

!

!

! !

!!

! !

!!! !

!

!

!

!

!

!

!

!

!

!

! !

!!

!

!

!

!

!

!

!

!

!

!

!

!

! !

! !

!! !

!!

!

!

! ! !!

! !

!!

! !

!

!

!

!! ! ! !

!!

!

!!

!

!!

! ! !!

!

!

!

!

!

!

!

!

! ! ! !!

!

!

!

! !

!

!

!

!

!

!

!

!

! ! ! !

! !

!

! !

! !

!

!

!

!

!

!

!

! ! !

!

!!

! !

! ! !

!

!

!

!

!

!!

!

!

!! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!!

! !

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!!

!!

! !

!

!

!

!

!

!

!

!

!

! !

!

!

!

!! !

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!!

!

!

!!

!!

!

!

!

!

!

!

!

! !!

! ! !

! !

!

!

! !

!

!

!

!

!

!

! !

!

!

!

! !

!

!

!

!

! !

!

!

!

!

!

!

!

! !

!

!

!

! !

!

!

!

! !

!

!! !

!

!

!

!

!

!

!

!

!!

!

! !

!

!

!

!

!

! !

!

!

!

!

!

!!

!

!

!

!

!

!

! ! !

! ! !

!

!!

!

!

!

! !

!

! !

!

!

!

!

!

! !

!

!!!

!

!

!

! !

!

!

!

!

!

!

! !

!

! !

!

! !

!

!

!

! ! !

!

!

!!!

! !

!

!! !

!

!

! ! ! ! !

!

!

!

!

!! ! ! !

!!

!

!

!

! ! !

!

!

!

!

!

!

!

!

!!

!

!!

!

!

!

!

!

!

!

!

!

!

!

!! !!

!

!

!

!

! !

!

!!

!

!

!!

!!!

! !

! !

!

!

! !

! !

!

!

!

! !

! !

!

!

!

!

!

! !

!!

!

! !

!

!

! ! !

!

! !

!

!

!

! !

!

!

!!

!

!

!

!

! !!!

!!!!

!!

!

!!!

TX

CA

MT

AZ

ID

NV

NM

CO

OR

UT

IL

WY

KS

IA

SD

NE

MN

ND

OK

WI

FL

MO

WA

GA AL

MI

AR

IN

PA

LA

NY

NC

MS

TN

VA

KY

OH

SC

ME

WV

MI

VT

NH

CT

MD

NJ

MA

DE

RI

Offshore

Pacific

Offshore

Gulf

CANADA

MEXICO

130°W 120°W 110°W 100°W 90°W 80°W 70°W

40°N30°N20°N

CANADA

RUSSIA

AK

0 500 MILES 250

120°W 130°W 140°W 150°W 160°W 170°W 180° 170°E

65°N60°N55°N50°N

HI

0 150 MILES 75

156°W 158°W 160°W 162°W

24°N22°N20°N

EXPLANATION

Federal landOCS boundaryOCS platform !

0 200 400 MILES0 200 400 KILOMETERS

Map image is the intellectual property of Esri and is used herein under license. Copyright © 2013 Esri and its licensors. All rights reserved.
Fossil Fuel-Associated Emissions of Greenhouse Gases from Federal Lands 3

of current industrial sequestration and a paucity of available data. Ecosystems can also sequester or emit greenhouse 

gases. Therefore, the estimated fossil fuel-associated emissions are supplemented with the estimated net flux of carbon 

associated with plants and other organisms (ecosystems) on 

Federal lands. The inclusion of ecosystem estimates provides 

the opportunity to calculate a net emission result (for carbon 

dioxide [CO2] only) by comparing the fossil fuel-associated 

emissions estimates with those for carbon stored or released 

from ecosystems on Federal lands. For clarity and brevity, 

in this report, the term “emissions” generally, but not exclusively, refers to fossil fuel-associated emissions and the term 

“sequestration” commonly refers to sequestration in terrestrial 

ecosystems. However, both industrial fossil fuel activities and 

ecosystems emit and sequester greenhouse gases. For ease of 

comparison between fossil fuel-associated emissions and ecosystems flux estimates, the values in this report are presented 

in equivalent amounts of CO2 gas.

The discussion of the estimates is separated into two sections: “Fossil Fuel-Associated Emissions of Greenhouse Gases 

from Federal Lands” and “Terrestrial Ecosystems-Associated 

Carbon Emissions and Sequestration on Federal Lands.” The 

first covers emissions of CO2, methane (CH4), and nitrous 

oxide (N2O) from the extraction and eventual end-use combustion of fossil fuels produced on Federal lands, and the second 

deals with the sequestration and emission of carbon in terrestrial ecosystems on Federal lands. Both sections detail the data 

sources, methodology, and results specific to the estimates. 

The report concludes with a discussion of the net emissions 

attributed to Federal lands; these are the estimates produced 

by summing the emissions and sequestration results. Appendixes 1 and 2 supply additional information regarding the data 

sources and methodology.

Fossil Fuel-Associated Emissions of 

Greenhouse Gases from Federal Lands

Introduction

For the emissions portion of this study, we estimated the 

greenhouse gas emissions (CO2, CH4, and N2O) resulting from 

the extraction and end-use combustion of fossil fuels derived 

from U.S. Federal lands, including offshore areas. The Gulf 

of Mexico Outer Continental Shelf (OCS) and Pacific OCS 

planning areas are included in this report and referred to as 

offshore Gulf and offshore Pacific, respectively. No other OCS 

areas are included in this report because they did not produce 

fossil fuels during the period of this study. Emissions are 

produced through two processes: (1) the combustion of fuel 

for electricity generation, mechanical work, heating, or use as 

a feedstock and (2) the fugitive emission of gases during the 

processes of extracting and moving fuel. Fugitive emissions 

were attributed to the areas where the fuels originated; the 

location of the eventual combustion of the fuel, whether on 

Federal, State, private, or international territory, was not a factor. If the fuel was sourced on Federal lands, it was included 

in the estimate regardless of where it was used. All references 

to emissions in this section are associated with fossil fuels 

extracted from Federal lands in States and offshore areas. 

American Indian and Tribal lands were not included in this 

analysis.

Data Sources

Four main types of data support the emissions estimates in this report: (1) Federal lands fuel (oil, gas, and coal) 

production; (2) emissions from coal mines and oil and gas 

infrastructure (fugitive emissions); (3) national- and Statelevel energy-consumption and emissions data for apportioning extracted fuel to end-use fuel type and economic sector; 

and (4) process-specific emission factors that determine the 

volumes of greenhouse gases emitted by combusted fuels. A 

general discussion of the data sources is provided here, and an 

in-depth listing of data sources is provided in appendix 1.

Data on Federal lands fuel production are collected as 

part of royalty tracking by the Office of Natural Resources 

Revenue (ONRR) in the U.S. Department of the Interior. The 

ONRR is the Federal data source for revenue generated from 

fuel production on Federal lands. Production data collected by 

the ONRR (made available to the USGS via Memorandum of 

Agreement MOA16–5285) were the main input to the emission estimate calculations. These values include coal, oil, and 

natural gas production from Federal lands in 28 States and 

the Federal offshore Pacific and offshore Gulf. No fossil fuels 

were produced on Federal lands in the remaining 22 States or 

the Atlantic and Alaska offshore areas during the study period. 

In addition, the ONRR production data provided to the USGS 

Figure 1 (facing page). Map showing the onshore Federal lands 

(excluding American Indian and Tribal lands) and offshore Federal 

Outer Continental Shelf (OCS) planning areas (offshore Pacific 

and offshore Gulf) included in the emissions and sequestration 

estimates. The Federal Atlantic and Alaska OCS planning areas 

were excluded because they did not have fossil fuel production 

during the study period. Federal lands were modified from 

the U.S. Geological Survey Protected Areas Database of the 

United States (U.S. Geological Survey, 2016). OCS boundaries 

and platforms are from Minerals Management Service (2006a, b), 

Bureau of Ocean Energy Management (2011), and Bureau of 

Safety and Environmental Enforcement (2014).
4 Federal Lands Greenhouse Gas Emissions and Sequestration in the United States: Estimates for 2005–14

could not be attributed to specific Federal land management 

agencies. Data from the ONRR were available at the level of 

detail required for this project starting in 2005; data availability was through 2014, the final complete year when this 

project began.

Fugitive emissions include measured or estimated 

releases of CH4 from underground and surface coal mines 

(both active and abandoned) and CO2 and CH4 emissions from 

oil and gas infrastructure such as wells, pipelines, compressors, and storage tanks. These data were provided by the EPA 

but collected by the Mine Safety and Health Administration 

(MSHA). The MSHA measures emissions from some underground coal mines, and mine operators submit other emissions 

estimates and measurements to the EPA’s Greenhouse Gas 

Reporting Program.

The third set of values required to complete the emissions 

estimate consists of national- and State-level energy production, sector usage, refining, and export statistics. The source 

of these statistics is the U.S. Energy Information Administration (EIA), which is part of the U.S. Department of Energy. 

These published statistics (see references in appendix 1) were 

used to generate ratios for apportioning the Federal production volumes to end-use fuel types and economic sectors. This 

allocation was necessary because it is often impossible to track 

coal, oil, or gas from a specific Federal source as it moves 

through the fuel supply system to its eventual endpoint where 

emissions are generated. Fuels from most Federal lands are 

combined with fuels from private and State lands in pipelines, 

containers, or shipments, and once combined, the origins of 

the fuels are no longer traceable. In 2014, approximately 42 

percent of the total crude oil produced in the United States was 

refined into motor gasoline (U.S. Energy Information Administration, 2015c). We assumed that this ratio also holds for 

crude oil from Federal lands, such that if a State produced 1 

million barrels of oil from Federal lands, it would be assumed 

that 42 percent of the 1 million barrels was refined into motor 

gasoline. Though the actual number is certainly different, it is 

not possible with the currently available data to determine the 

amount of motor gasoline produced from a State’s Federallands crude oil. Ratio-based scaling from national- or Statelevel production volumes was used throughout the estimate 

calculation for amounts of products refined from crude oil, 

industrial uses of natural gas, sector usage for coal combustion, and international fuel exports. The specific EIA sector 

usage, refining, and State export reports used in this calculation are listed in appendix 1.

Emission factors are the values used to convert volumes 

of fuel combusted into amounts of greenhouse gases emitted. 

These conversions differ by the input fuel and the sector of the 

economy where that fuel is consumed. The EPA’s Inventory 

of U.S. Greenhouse Gas Emissions and Sinks (hereafter EPA 

Inventory; U.S. Environmental Protection Agency, 2016b), an 

annual publication of total U.S. greenhouse gas emissions, is 

the source of all emission factors used in this study. In addition, the EPA Inventory’s calculation methodology is the basis 

for the methods used in this study.

Methodology

Introduction

The methods used in this study to estimate greenhouse 

gas emissions from fossil fuel produced on Federal lands are 

adapted from the more exhaustive methodology described 

in the EPA Inventory and its associated annexes (U.S. Environmental Protection Agency, 2016a, b). The EPA Inventory 

follows the guidelines set by the United Nations Framework 

Convention on Climate Change to produce a common and 

consistent mechanism for estimating sources and sinks of 

anthropogenic greenhouse gases that will allow for relative 

comparisons of different emissions sources (U.S. Environmental Protection Agency, 2016b). The United States signed and 

ratified the United Nations Framework Convention on Climate 

Change in 1992, and the EPA has produced its Inventory since 

1997. The EPA methodology is consistent with that recommended in the Intergovernmental Panel on Climate Change’s 

“2006 IPCC Guidelines for National Greenhouse Gas Inventories” (Intergovernmental Panel on Climate Change, 2006).

The USGS estimation method differs from the EPA 

method in scale, scope, and complexity. Calculation of emissions estimates at the scale of Federal lands and individual 

States is how the USGS process varies the most from the EPA 

Inventory’s methodology. Fine-scale estimates are generally 

achieved through a bottom-up calculation method; however, 

the USGS could not obtain State-level data for some parameters. Unavailable inputs were produced by scaling down 

national-level data from the EPA and EIA. This process is 

explained in the following sections and in appendix 1.

In terms of scope, the USGS was tasked with investigating the emissions associated with the extraction of fossil fuels 

on Federal lands and their end-use combustion. Therefore, the 

USGS estimate is restricted to only the emissions covered in 

the “Energy” chapter of the EPA Inventory and does not include 

emissions from agricultural, industrial, or waste-processing 

activities. Simply stated, the USGS scope discussed in this 

report is much narrower than that assigned to the EPA. There is, 

however, one exception: we included an estimate for the enduse combustion emissions of fossil fuels that were produced on 

Federal lands and exported internationally. As explained in the 

“Exported Fuels Emissions” section, the emissions from these 

products are not included in the EPA Inventory.

Emissions estimates provided in the EPA Inventory are 

the official estimates for the United States and, as such, are 

produced with annual reviews and refinements by a team of 

researchers. This USGS study does not strive to improve the 

EPA’s methodology but instead to utilize it. In summary, this 

USGS estimate borrows heavily from the portion of the EPA 

method concerning energy-related emissions and is adapted to 

produce State-level outputs by using inputs specific to Federal 

lands. The EPA and USGS methods are not competing methods, and the USGS method is not an improvement on any part 

of the EPA method.
Fossil Fuel-Associated Emissions of Greenhouse Gases from Federal Lands 5

The following sections highlight the general process 

used to generate the estimates in this study. Because the EPA 

Inventory served as the main guiding document, this report 

cites those methods rather than restating them. Introductory 

information, differences in methods, and process steps that 

require additional clarification are discussed in the following 

sections. For specific process steps and tables of data sources, 

refer to appendix 1.

Stationary Combustion Emissions

Stationary emissions encompass greenhouse gas emissions from the combustion of fossil fuels in nonmobile (nontransportation) sectors. These sectors include the combustion 

of coal for electricity generation, commercial use, industrial 

use, and coking coal production. Burning natural gas for 

electricity generation and the use of natural gas as a feedstock 

in industrial processes are also included. Refining crude oil 

to produce liquid fuels used to generate heat or electricity 

also represents stationary emissions. Various emission factors were used to convert the amounts of fuel combusted into 

estimates of emissions. Currently, emission factors available 

in the literature are generally fuel or end-use sector specific. 

Because of their various uses, the emission factors for stationary combustion of liquid fuel are fuel specific. Emission 

factors for natural gas and coal are based on the sectors of the 

economy where the fuels are used. For example, stationary 

coal combustion emission factors are based on the combustion 

of mixed ranks of coal in specific sectors of the economy, such 

as electricity generation versus industrial coking, rather than 

coal rank, such as the amount of bituminous versus lignite coal 

used. The use of sector-specific versus rank-specific emission 

factors allowed the methodology to leverage detailed coal 

datasets that include annual coal consumption by State of origin and end-use sector (but not by rank) for all coal use in the 

United States. See appendix 1 for a detailed list of data sources 

for stationary combustion emissions.

Mobile Combustion Emissions

Calculations of mobile emissions are complicated by the 

changing technology, efficiency, and total mileage of vehicles 

driven, flown, and piloted in the United States in any given 

year. Considering this reality, the USGS method leans heavily on the national emissions calculations included in the 

EPA Inventory and associated annexes (U.S. Environmental 

Protection Agency, 2016a, b). The national-level data from the 

EPA were devolved to ratios of greenhouse gas emissions per 

gallon of fuel. The ratios were then multiplied by the gallons 

of fuels that were estimated to have been refined from crude 

oil produced from Federal lands. The USGS estimate therefore 

provides emissions estimates for only the fuels that the EPA 

has estimates for. These are the major fuels—motor gasoline, 

aviation gasoline, jet kerosene, diesel oil, residual fuel oil, and 

liquefied petroleum gas—and account for nearly all mobile 

emissions.

Petroleum and Natural Gas Systems Emissions

This section covers calculations for greenhouse gases 

released during the extraction and transportation (for example, 

through pipelines) of natural gas and oil on Federal land, 

as well as platforms in Federal offshore areas. These types 

of emissions are generally referred to as fugitive emissions. 

All fugitive emissions estimates made by the USGS follow 

a methodology similar to that used for mobile emissions. 

Because of the complexity involved in determining the 

emissions from natural gas and oil infrastructure, the USGS 

relied on the established work of the EPA Inventory rather 

than attempting to generate the emissions values separately. A 

ratio of emissions per well, including fugitive emissions from 

production through distribution for gas and from production 

through refining for oil, was generated from the EPA Inventory’s national emissions estimates (U.S. Environmental Protection Agency, 2016b). This ratio was multiplied by the number 

of wells producing oil and gas from Federal lands (Bureau of 

Land Management, written commun., 2016) to estimate the 

emissions associated with oil and gas infrastructure on those 

lands. For offshore platforms, the EPA has produced per platform emissions rates that are based on the depth and type of 

hydrocarbon produced. These rates were used to determine the 

emissions associated with platforms producing in the Federal 

offshore Pacific and offshore Gulf areas (U.S. Environmental 

Protection Agency, 2015).

Active Coal Mine Emissions

Emissions from active coal mines were estimated only 

for CH4 at underground and surface mines by using methods 

outlined in annex 3.4 of the EPA Inventory (U.S. Environmental Protection Agency, 2016a). CH4

 gas is released both during 

mining and after mining as coal is degassed while in transport and processing. Data for active underground coal mine 

emissions are collected by the MSHA and reported by mine 

operators to the EPA Greenhouse Gas Reporting Program. 

Postmining emissions from underground mines are based 

on the amount of coal produced from the mine, as well as a 

basin-specific coal CH4 content factor. Active surface mine 

emissions were calculated in a way similar to the postmining 

emissions from underground coal mines. Postmining emissions from surface mines are based on data collected by the 

MSHA or reported by mine operators, similar to emissions 

from active underground mines.

Abandoned Coal Mine Emissions

Even after an underground mine has stopped actively 

producing coal, the remaining coal releases CH4 gas for some 

time. An abandoned mine can be sealed, vented, or flooded 

as groundwater permeates the mine. The method of abandonment will affect the amount and rate of CH4

 released. In 

general, mines will release the most CH4 immediately after 

abandonment, and the rate will decrease over time. The 
6 Federal Lands Greenhouse Gas Emissions and Sequestration in the United States: Estimates for 2005–14

rate of decline and the effects of the geology and method of 

abandonment are explained in the EPA’s methodology for 

estimating abandoned mine emissions (Franklin and others, 

2004; U.S. Environmental Protection Agency, 2004). We used 

a slightly simplified nonprobabilistic version of the method 

used by the EPA. See appendix 1 for more details on the 

calculation.

Exported Fuels Emissions

End-use emissions associated with fossil fuels exported 

from the United States are not included in the EPA Inventory. 

The Intergovernmental Panel on Climate Change’s “2006 

IPCC Guidelines for National Greenhouse Gas Inventories” 

(Intergovernmental Panel on Climate Change, 2006) specified that emissions are counted in the nation where they were 

emitted; therefore, the EPA includes combustion emissions 

from imported fuel but not exported fuel. The USGS estimate 

includes a separate output for emissions from the combustion 

of fuels produced on Federal lands and exported. However, it 

is important to note that oil or gas from specific wells or even 

fields cannot be traced through the U.S. energy system. Coal 

from some mines may be traceable because of the method of 

transportation, but those data are not available to the USGS. 

Therefore, exported fuel amounts were estimated on the basis 

of national (oil and gas) or State (coal) export data provided 

by the EIA (U.S. Energy Information Administration, 2015b, 

2016a, 2016b). Exported oil, gas, and coal volumes were separated from the gross State production in each of the methods 

described above. The export volumes were then separately run 

through the same calculation as the domestic fuel volumes. 

Essentially, the USGS method calculated a small subset of 

international emissions. To do this, we assumed that the emission factors in the United States are the same as those in the 

countries that imported the fuels. Domestic sector proportions 

specific to each State (if available) and year were the same as 

those used for the export estimates. These generalized assumptions were necessary because separating the exports by the 

nations that imported them, determining sector usage proportions for each nation, and using emission factors specific to 

those nations would amount to an unwarranted level of effort 

to expend on already estimated export volumes.

Results

The USGS estimates of emissions from the combustion 

of fossil fuels produced on Federal lands include output values 

for CO2, CH4, and N2O gases in 28 States, offshore Pacific, 

and offshore Gulf for the years 2005 through 2014. The results 

are further segmented by emission category, the sector of the 

economy, and often, the specific fuel used. Emission categories include stationary combustion, mobile combustion, active 

coal mining, and others. Examples of sectors include coal used 

for electricity generation, coal used for industrial applications, diesel oil, natural gas infrastructure, and offgassing from 

active mines. Because of data availability and method limitations, emissions for each of the three gases were not estimated 

for all categories, sectors, and fuels. The total numbers of 

output estimates generated by gas type are 15 for CO2, 13 for 

CH4, and 9 for N2O. Table 1 contains the USGS emissions 

estimates for Federal lands in 2014. All results are reported in 

million metric tons of CO2 equivalent (MMT CO2 Eq.). The 

conversion to CO2 equivalents enables direct comparison of 

the different gases. To make the conversion, the amounts of 

gases are multiplied by their global warming potential, a factor 

that accounts for the effect a specific gas has in warming the 

atmosphere relative to the effect of CO2; the values for the 

three gases are 1 for CO2, 25 for CH4, and 298 for N2O (Intergovernmental Panel on Climate Change, 2007).

The emissions estimates generated during this study 

span a 10-year period from 2005 to 2014 and pertain to 30 

geographic areas and 37 sector- or fuel-specific outputs. 

Therefore, the figures and tables presented in this report only 

summarize the results and are not intended to be a complete 

presentation of all results. The full dataset is available online 

at https://doi.org/10.5066/F7KH0MK4 (Merrill and others, 

2018). An interactive map is available at https://eerscmap.

usgs.gov/fedghg.

Nationwide emissions from fuels extracted from Federal 

lands in 2014 were 1,279.0 MMT CO2 Eq. for CO2, 47.6 MMT 

CO2 Eq. for CH4, and 5.5 MMT CO2 Eq. for N2O. The 2014 

totals represent decreases in emissions for all three greenhouse 

gases compared to 2005 values, with reductions of 6.1 percent 

for CO2, 10.5 percent for CH4, and 20.3 percent for N2O. 

Total emissions from the production and combustion of fossil 

fuels produced on Federal lands for the years 2005–14, as 

well as comparisons to total U.S. emissions, are presented in 

table 2. On average, Federal lands fuels emissions from 2005 

to 2014 accounted for 23.7 percent of national CO2 emissions, 

7.3 percent for CH4, and 1.5 percent for N2O (table 2).

In 2014, Wyoming, offshore Gulf, New Mexico, Louisiana, and Colorado had the highest CO2

 emissions from fuels 

produced on Federal lands (fig. 2). The CO2 emissions attributed to Federal lands in Wyoming are 57 percent of the total 

from Federal lands in all States and offshore areas combined. 

Emissions estimates for the release of CH4 are also highest 

for Federal lands in Wyoming (28 percent), followed by New 

Mexico, offshore Gulf, Colorado, and Utah (fig. 3).

Unsurprisingly, the trends and relative magnitudes of the 

emissions estimated are roughly parallel to the Federal lands 

production volumes (U.S. Energy Information Administration, 2015a). States that produced the most fuel from Federal 

lands are associated with the highest emissions for CO2, CH4, 

and N2O. These relationships vary slightly relative to absolute 

production because different fuels require different extraction 

methods and fuel uses emit varying amounts of greenhouse 

gases. Trends in emissions over the 10 years of the estimate 

could indicate changes in production volumes; however, in 

States where multiple fuels were produced, these relationships may not be evident or direct. Although emission factors, 

numbers of producing wells, vehicle efficiency, and sector 
Fossil Fuel-Associated Emissions of Greenhouse Gases from Federal Lands 7

Table 1. National totals and subtotals for several categories of greenhouse gas emissions associated 

with the combustion and extraction of fossil fuels from U.S. Federal lands in 2014.

[The full dataset associated with this study (Merrill and others, 2018) contains similar data for 28 States and two offshore 

areas for 2005–14. For the sector subtotals, the number of significant figures indicates the precision in the underlying 

State-level estimates. The emissions category totals and Federal lands emissions totals are national totals summed from 

individual estimates and not the subtotals presented in this table. Therefore, the subtotals listed here may not sum to the 

national totals. All national totals are reported to one decimal place if greater than 1.0 million metric tons of carbon dioxide 

equivalent (MMT CO2 Eq.) or to two significant figures if less than 1.0 MMT CO2 Eq. CO2, carbon dioxide; CH4, methane; 

N2O, nitrous oxide; —, values not calculated]

Sector/fuel CO2

 emissions 

(MMT CO2 Eq.)

CH4 emissions 

(MMT CO2 Eq.)

N2O emissions 

(MMT CO2 Eq.)

Combustion emissions from stationary sources

Coal: electricity generation 725.36 2.09 3.68

Coal: industrial 9.3 0.0268 0.047

Coal: industrial coking 0.016 0.00005 0.00009

Coal: commercial 0.21 0.0006 0.001

Petroleum products 41.77 0.039 0.095

Natural gas 217 0.10 0.12

Stationary total 993.6 2.3 3.9

Combustion emissions from mobile sources

Motor gasoline 110.892 0.143 1.239

Aviation gasoline 0.3 — —

Jet kerosene 25.58 — —

Diesel oil 58.25 — 0.06

Residual fuel oil 4.61 — —

Liquefied petroleum gas 0.078 — —

Mobile total 199.7 0.14 1.3

Extraction emissions from petroleum and natural gas systems

Petroleum wells, equipment, and platforms 0.18 7.97 —

Natural gas wells, equipment, and platforms 5.3 25.31 —

Extraction emissions from coal mining

Surface mines — 4.34 —

Underground mines — 6.20 —

Abandoned mines — 1.22 —

Coal mining total — 11.8 —

Total emissions from Federal lands

Domestic 1,198.8 47.5 5.2

Exported 80.2 0.10 0.27

Total Federal lands 1,279.0 47.6 5.5
8 Federal Lands Greenhouse Gas Emissions and Sequestration in the United States: Estimates for 2005–14

Table 2. National totals for greenhouse gas emissions associated with the combustion and extraction of fossil fuels from U.S. 

Federal lands in 2005–14.

[CO2, carbon dioxide; CH4, methane; NO2, nitrous oxide; MMT CO2 Eq., million metric tons of carbon dioxide equivalent]

Year

CO2 emissions CH4 emissions N2O emissions

Federal lands 

fossil fuels 

(MMT CO2 Eq.)

Percentage of 

U.S. total1

Federal lands 

fossil fuels 

(MMT CO2 Eq.)

Percentage of 

U.S. total1

Federal lands 

fossil fuels 

(MMT CO2 Eq.)

Percentage of 

U.S. total1

2005 1,361.9 22.2 53.2 7.4 6.9 1.7

2006 1,378.6 22.8 53.4 7.4 6.8 1.7

2007 1,398.3 22.8 53.8 7.4 6.4 1.5

2008 1,427.9 24.1 55.8 7.6 6.5 1.6

2009 1,422.5 25.9 53.4 7.3 6.7 1.7

2010 1,429.4 25.1 53.3 7.4 6.6 1.6

2011 1,362.4 24.5 55.7 7.8 6.2 1.5

2012 1,280.5 23.9 52.0 7.3 5.7 1.4

2013 1,210.5 22.0 48.8 6.8 5.4 1.3

2014 1,279.0 23.0 47.6 6.5 5.5 1.4

1

Percentages calculated from total U.S. emissions (U.S. Environmental Protection Agency, 2016b).

usage rates all change from year to year, they have minimal 

effect on the final emissions results compared to the amount 

of fossil fuel production. Any significant changes in production will result in a similar change in the attributed emissions. 

Federal lands fuels production by State (U.S. Energy Information Administration, 2015a) is therefore very similar in relative 

magnitude to the emissions results presented in this report.

Uncertainty of Emissions Estimates

The emissions estimates in this report do not include 

estimates of uncertainty. Calculated uncertainties provided in 

the annexes to the EPA Inventory (U.S. Environmental Protection Agency, 2016a, annex 7) are informative and presumed to 

be applicable because the USGS employed a slightly modified 

EPA methodology. In summary, the EPA determined that the 

emissions estimate uncertainty was smaller for combustion 

calculations than uncertainties for fugitive emissions from 

extractive activities. This difference in uncertainties is intuitive because combusted materials are measured for sale and 

therefore are well constrained, whereas the amounts of gases 

emitted from extraction are often estimated or scaled up from 

smaller sampling efforts. For example, the annexes to the EPA 

Inventory (U.S. Environmental Protection Agency, 2016a, 

annex 7) cited uncertainty with a 95-percent confidence interval from −2 to 5 percent of the 2014 mean CO2

 emissions from 

fossil fuel combustion. In contrast, nonenergy CO2 emissions 

uncertainties ranged from −25 to 42 percent. Uncertainties for 

CH4 emitted by coal mining ranged from −12 to 15 percent. 

Overall, owing to the significant proportion of emissions tied 

to the combustion of fossil fuels, the total uncertainty of the 

EPA Inventory estimate was between −2 and 5 percent.

Precision and Rounding of Emissions Estimates

The emissions estimates summarized in this report and 

provided in the associated dataset (Merrill and others, 2018) 

were formatted in an effort to indicate their precision. For 

all nontotal values, meaning those estimates that represent a 

single sector, gas, State, and year combination, the number of 

significant figures indicates the level of precision inherent in 

the calculations that generated that number. In the calculations 

used to generate the estimates, accurate but less precise sector 

ratios or emission factors are commonly the parameters with 

the least precision, and they limit the estimate’s precision.

For the convenience of the reader, this report and the 

associated dataset include totals for grouped sectors such as 

stationary combustion, mobile combustion, and coal mine 

fugitive emissions. Totals for domestic, exported, and overall 

total emissions are also included. These totals are formatted in 

a specific way to capture the 12 orders of magnitude in range 

present in the various estimates of this dataset. Totals greater 

than or equal to 1.0 MMT CO2 Eq. are rounded to the first 

decimal place, whereas values less than 1.0 MMT CO2 Eq. are 

shown with two significant figures. This method of representing the estimates, used only for totals, facilitates the comparison of emissions totals that are below 1.0 MMT CO2

 Eq.

Performing calculations on the rounded total values, such 

as summing State total emissions rather than all individual 

sector emissions, to obtain national emissions will incur and 

possibly compound rounding errors. Users of the dataset are 

advised to perform calculations on the individual values rather 

than the rounded totals. All totals in this report were calculated 

from the underlying individual estimate values and are deemed 

accurate; the totals are not summations of subtotals.
Fossil Fuel-Associated Emissions of Greenhouse Gases from Federal Lands 9

Wyoming

727.7

57%

Offshore Gulf

235.4

19%

Louisiana

56.0

5%

Colorado

49.6

4%

Utah

43.1

3%

Montana

42.1

3%

North Dakota

17.0

1%

California

12.8

1%

Texas

7.2

1% Other

7.5

1%

New Mexico

80.6

6%

Figure 2. Pie chart showing carbon dioxide emissions 

associated with the extraction and combustion of fossil 

fuels produced from Federal lands in the 10 States 

or offshore regions with the highest emissions, 2014. 

Emissions are reported in million metric tons of carbon 

dioxide equivalent (MMT CO2

 Eq.).

Wyoming

13.1

28%

New Mexico

10.8

23%

Offshore Gulf

9.5

20%

Colorado

6

13%

Utah

3.5

7%

Alabama

1.3

3%

Montana

1.2

3%

California

0.6

1%

North Dakota

0.24

0%

Oklahoma

0.21

0% Other

1.14

2%

Figure 3. Pie chart showing methane emissions 

associated with the extraction and combustion of fossil 

fuels produced from Federal lands in the 10 States 

or offshore regions with the highest emissions, 2014. 

Emissions are reported in million metric tons of carbon 

dioxide equivalent.
10 Federal Lands Greenhouse Gas Emissions and Sequestration in the United States: Estimates for 2005–14

Terrestrial Ecosystems-Associated 

Carbon Emissions and Sequestration 

on Federal Lands

Introduction

For the ecosystems emissions and sequestration portion 

of the USGS study, we estimated the annual amount of CO2

that was stored and emitted by terrestrial ecosystems, including forests, grasslands, shrublands, and agricultural lands. 

Plants convert CO2 to carbon through photosynthesis, which is 

expressed as gross primary productivity (GPP). See table 3 for 

a summary of the terms introduced in this section. The terms 

include stocks, the amount of carbon present in a carbon reservoir, and fluxes, annual changes to those stocks that can be 

additions (sequestration) or removals (emissions). Autotrophic 

respiration (Ra) is the release of CO2 back to the atmosphere 

by plants through respiration. The difference between GPP 

and Ra is referred to as net primary productivity (NPP), or the 

amount of CO2 fixed or stored in new vegetation each year. 

Ecosystems also respire CO2 through the decay and decomposition of dead organic matter (DOM), referred to as heterotrophic respiration (Rh). The total net ecosystems productivity 

(NEP) can thus be estimated as GPP − (Ra + Rh).

Changes to ecosystems, typically caused by wildfires 

(fire) and forest harvest (harvest), are considered forms of 

land-use and land-use and land-cover (LULC) change. Other 

forms of LULC change, including agricultural harvesting, are 

grouped in a separate category in this study (other). These 

changes typically result in the removal of carbon from the ecosystem and are therefore considered emissions for the purpose 

of this study. Ecosystem carbon losses associated with land 

use and land-use change and disturbance are subtracted from 

NEP to estimate net biome productivity (NBP), which reflects 

the absolute change in carbon stored within ecosystems on an 

annual basis. NBP is an appropriate value for comparison with 

annual fossil fuel-associated emissions and is used again in 

this report where the concept of net emissions is introduced. In 

the full dataset associated with this study (Merrill and others, 

2018), we provide estimates of most of the stocks and fluxes 

in table 3. Estimates are included for carbon stocks such as 

TEC, Live, DOM, and Soil and annual carbon fluxes such as 

Rh, NPP, NEP, NBP, fire, harvest, and other for Federal lands 

of the United States for the period 2005–14.

Data Sources

This USGS study used three main sources to estimate the 

carbon balance on Federal lands of the United States. For the 

conterminous United States (CONUS), we analyzed the results 

of net ecosystem carbon fluxes produced by a dynamic global 

vegetation model. For the State of Hawaii, we estimated 

ecosystem carbon balance by using a look-up table approach 

based on results from a recent USGS assessment of carbon 

storage and fluxes (Selmants and others, 2017). The net carbon 

balance for Alaska was estimated from another recent USGS 

assessment (Zhu and McGuire, 2016). These three existing 

sources contain estimates that span different ranges of years, 

all longer than the span of this study; however, the results 

from those additional years are not included in this report or 

the associated dataset because they do not match the study 

period for the fossil fuel-associated estimates (2005–14). Here 

we provide an overview of the sources used to estimate the 

net carbon balance on Federal lands. Additional details are 

provided in appendix 2.

We estimated carbon balance on Federal lands of the 

CONUS by analyzing spatially explicit maps of net carbon 

fluxes produced by using a process-based dynamic global 

vegetation model (Liu and others, 2016). Carbon stock and 

flux maps were estimated by using the Integrated Biosphere 

Simulator (IBIS) model (Foley and others, 1996; Kucharik and 

others, 2000). The IBIS model was used to estimate changes in 

carbon stocks and fluxes for the period 1970–2015 at approximately 1-kilometer (km) x 1-km resolution for all forests, 

grasslands, shrublands, wetlands, and agricultural land areas 

within the CONUS. Annual maps of carbon stocks and fluxes 

were combined with maps of Federal lands to produce annual 

estimates of carbon balance by State for the 45-year period.

Carbon fluxes for the State of Hawaii were derived 

through an analysis of data produced in support of the USGS 

biological carbon sequestration assessment for the State 

(Selmants and others, 2017). The assessment included estimates of carbon stocks and fluxes for forests, grasslands, and 

shrublands across three moisture zones (dry, mesic, and wet). 

Average annual carbon stock and flux densities were developed for the current study and applied to the State’s Federal 

land area.

For Alaska, estimates of ecosystem carbon dynamics 

were based on the USGS biological carbon sequestration 

assessment for the State (Zhu and McGuire, 2016). The Alaska 

assessment yielded estimates of carbon stocks and fluxes from 

uplands and wetlands across a baseline period of 1950–2010. 

The Alaska assessment produced a set of mean annual carbon 

stock and flux maps for the period 2001–10 that were used to 

estimate the average carbon balance of Alaska’s Federal lands.

Methodology

 Because of differences in existing work, calculation 

model structure, and data availability, the estimates of ecosystems carbon emissions and sequestration were prepared 

separately for the CONUS, Alaska, and Hawaii. The CONUS 

analysis was based on simulations that used the IBIS model 

(Liu and others, 2016). The Alaska data were modified from 

existing work by Zhu and McGuire (2016), and the Hawaii 

results were modified from Selmants and others (2017). The 

methodologies behind these three estimates are discussed 

briefly here and with more detail in appendix 2.
Terrestrial Ecosystems-Associated Carbon Emissions and Sequestration on Federal Lands 11

Table 3. Explanation of carbon stock and flux terms from the terrestrial ecosystem sequestration calculations.

[Terms are grouped by carbon stock or typical flux type. This table may be useful in viewing the results in tables 4 and 5. CO2, carbon dioxide]

Term Name Explanation

Stocks: terrestrial carbon reservoirs

TEC Total ecosystem carbon Total carbon stored in an ecosystem; the combination of carbon stored in soils, DOM, 

and live vegetation.

Live Live vegetation Carbon stored in live vegetation, both above and below ground.

Soil Soil organic matter Carbon stored in the organic material of soils.

DOM Dead organic matter Carbon stored in dead organic matter.

Fluxes: carbon sequestration

GPP Gross primary productivity CO2 removed from the atmosphere and converted to carbon by plant photosynthesis.

NPP Net primary productivity The difference between GPP and Ra. The amount of CO2 fixed or stored in new 

vegetation each year.

NEP Net ecosystems productivity GPP − (Ra + Rh)

NBP Net biome productivity Ecosystems carbon losses caused by land-use and land-cover change and disturbances. 

The absolute change in carbon stored within ecosystems.

Fluxes: carbon emissions

Ra Autotrophic respiration CO2 released to the atmosphere by plant respiration.

Rh Heterotrophic respiration CO2 released to the atmosphere from decay of DOM

Fire Wildfire carbon flux Ecosystem carbon loss as CO2 released to the atmosphere during wildfire.

Harvest Forest harvest carbon flux Ecosystem carbon loss from forest timber harvest.

Other Other land-use/land-cover changes Ecosystem carbon loss from land use (agricultural harvest) and land-use/land-cover 

change other than fire and timber harvest.

Conterminous United States

We estimated carbon stocks and fluxes in the CONUS by 

using the IBIS model (Foley and others, 1996; Kucharik and 

others, 2000). We used a modified version of the IBIS model 

that includes nitrogen controls on the carbon cycle (Liu and 

others, 2005), LULC change, wildland fire effects (Liu and 

others, 2011, 2016), and CH4 emissions (Zhu and others, 2014).

IBIS includes 11 types of disturbances: (1) fire, 

(2) logging, (3) deforestation to grasslands and shrublands, 

(4) deforestation to cropland, (5) afforestation from grasslands and shrublands, (6) afforestation from agriculture, 

(7) urbanization from forest, (8) urbanization from grasslands and shrublands, (9) urbanization from cropland, 

(10) agricultural expansion from grassland and shrublands, 

and (11) agricultural contraction (cropland converting to grasslands and shrublands). Logging and fire events trigger carbon 

removal and tree mortality without changing the forest-cover 

fraction, allowing for forest regrowth. Other types of disturbance remove carbon from the landscape and alter land cover 

fractions. For example, the forest to cropland transition (deforestation) will reallocate the previous forest-cover fraction to 

the cropland-cover fraction and remove all forest carbon from 

the landscape. As a result, the following simulation year will 

have no forest productivity but more crop productivity owing 

to the increase in the cropland-cover fraction. Other disturbance types, such as insect-induced mortality, disease, and 

wind and weather, were not included in this study.

Federal lands in the CONUS were identified from the 

USGS Protected Areas Database of the United States (PADUS) 

version 1.4 (U.S. Geological Survey, 2016). A mask was created by selecting all PADUS polygons that had a Federal owner 

designation. These included lands managed by the Bureau of 

Land Management, U.S. Forest Service, U.S. Department of 

Defense, U.S. Department of Energy, Bureau of Reclamation, 

U.S. Army Corps of Engineers, National Park Service, National 

Oceanic and Atmospheric Administration, Natural Resources 

Conservation Service, and other Federal agencies. American 

Indian Lands and Tribal lands were not included in this analysis. Within the Federal lands mask, all coastal and offshore 

areas were excluded. The Federal lands layer was then aggregated to a single binary map and combined with U.S. State 

boundaries from the U.S. Census Bureau (https://www.census.

gov/geo/maps-data/data/cbf/cbf_state.html) to provide a unique 

State identification code for each Federal land cell. All processing was done at a spatial resolution of 960 meters (m) x 960 m 

using an Albers Equal-Area Conic projection. Although small 

changes in the extent of Federal lands may have taken place 

over the period of study, we assumed that the extent of Federal 

lands was unchanging over time.
12 Federal Lands Greenhouse Gas Emissions and Sequestration in the United States: Estimates for 2005–14

We used the Federal lands mask described above to 

extract seven key IBIS carbon stock and flux variables: NPP, 

NEP, NBP, total ecosystem carbon (TEC) stock, live vegetation carbon stock, emissions associated with wildfire, and 

carbon removals associated with LULC change. The IBIS 

output data consist of annual maps of each carbon stock and 

flux variable at 960-m x 960-m resolution. Each map was 

stored as a multilayer Network Common Data Form file with 

each layer representing a single year between 1971 and 2015. 

Processing of all data was done by using the raster package 

(Hijmans and van Etten, 2012) of the R statistical package (R 

Core Team, 2013). Each of the seven IBIS-variable Network 

Common Data Form files was imported into R as a multilayer 

raster brick object, and the coordinate reference system and 

spatial extents were defined. Next, we extracted carbon values 

for Federal lands by using the Federal lands mask, and the 

zonal function was used to calculate the mean carbon density 

in kilograms per square meter for each State in each year. To 

estimate the total carbon value for all Federal land cells within 

a State, we first calculated the total number of cells with valid 

data extracted by the Federal lands mask and then calculated 

the total area in square meters for each State. The total areas 

were then multiplied by the carbon densities and divided by 1 

billion to produce estimates of million metric tons of carbon. 

The carbon values were then multiplied by 3.67 to convert to 

million metric tons of CO2. To facilitate comparisons with the 

fossil fuel-associated emissions estimates and EPA Inventory 

estimates, all carbon stocks and sequestration are represented 

as negative values and all carbon releases or losses to the 

atmosphere are represented as positive values.

Alaska

Estimates of ecosystem carbon dynamics in Alaska were 

based on the USGS biological carbon sequestration assessment for the State of Alaska (Zhu and McGuire, 2016). For 

the Alaska assessment, researchers estimated carbon stocks 

and fluxes from uplands and wetlands across a baseline period 

spanning 1950–2010. For both uplands and wetlands, the 

Dynamic Organic Soil version of the Terrestrial Ecosystem 

Model (DOS-TEM; Genet and others, 2013) was used to 

estimate carbon stocks and fluxes for 1-km x 1-km simulation 

cells. Soil and vegetation carbon estimates from DOS-TEM 

were validated against a range of in situ data collected across 

a range of ecosystem types. For more detail on the Alaska 

ecosystem modeling, see Zhu and McGuire (2016).

To estimate carbon stocks and fluxes for Federal lands 

in Alaska, we used spatially explicit output from DOSTEM at 1-km spatial resolution. Spatially explicit decadal 

averages of five carbon parameters were obtained from 

the Scenarios Network for Alaska and Arctic Planning at 

http://ckan.snap.uaf.edu. Carbon flux parameters include 

mean annual NPP, Rh, and carbon losses owing to fire. 

Additionally, carbon stock estimates for soil and live vegetation were available. First, we calculated NEP by subtracting 

Rh from NPP. Because of data limitations, wildfire was the 

only carbon loss considered when estimating NBP, which was 

calculated by subtracting the burn map carbon losses from 

the calculated NEP map. Next, all carbon maps were spatially 

subset to include only Federal lands. Mean decadal carbon 

stocks and fluxes were then added as a stationary input to the 

annual totals calculated for the CONUS.

Hawaii

Carbon stocks and fluxes for the State of Hawaii were 

estimated on the basis of an analysis of the USGS biological 

carbon sequestration assessment for the State of Hawaii (Selmants and others, 2017). For the Hawaii assessment, researchers estimated mean annual carbon stocks and fluxes for 

forests, grasslands, and shrublands across three moisture zones 

(dry, mesic, wet) for the period 2001–16 (Sleeter and others, 

2017) by using the Land Use and Carbon Scenario Simulator 

(LUCAS) model. The LUCAS model included estimates and 

projections of the effects of land-use change, wildfire, and 

future changes in moisture zones on the carbon balance of terrestrial ecosystems. The LUCAS model was run in a spatially 

referenced mode, and spatially explicit maps of carbon stocks 

and fluxes were not produced.

Live vegetation and soil organic carbon (to 1-m depth) 

stocks for the seven main Hawaiian Islands containing Federal 

lands (Hawaii, Maui, Lanai, Kahoolawe, Molokai, Oahu, and 

Kauai) were estimated from spatially explicit maps developed 

for the USGS biological carbon sequestration assessment (Selmants and others, 2017). We then summarized the total carbon 

storage by intersecting the live vegetation and soil organic 

carbon maps with a map of Federal lands.

To estimate carbon fluxes for Federal lands in Hawaii, 

we extracted statewide total carbon estimates for the period 

2005–15 from a “no-change” scenario (where no changes in 

land use, fire, or climate were considered). Carbon densities 

were calculated on the basis of the distribution of the combinations of LULC classes (forest, grassland, shrubland) and 

moisture zones (dry, mesic, wet), which were assumed to be 

fixed through time. Next, we calculated the area of each LULC 

class type for the Federal lands of Hawaii by intersecting an 

LULC map (Jacobi and others, 2017) with a map of Federal 

lands extracted from the PADUS dataset. Lastly, we applied 

the State-level carbon densities to the Federal lands area to 

estimate carbon stocks and fluxes. It is important to note that 

because LULC change and disturbances were not considered, 

only NPP, Rh and NEP were estimated for Hawaii.

Results

The carbon sequestration results were calculated for 

various timeframes depending on geographic area and specific output. For comparison with the fossil fuel-associated 

emissions, the following results are provided for the years 

2005–14 only. In 2005, Federal lands of the CONUS stored 

82,289 MMT CO2 Eq. in terrestrial ecosystems (TEC). By 
Terrestrial Ecosystems-Associated Carbon Emissions and Sequestration on Federal Lands 13

2014, carbon storage was estimated at 83,600 MMT CO2 Eq., 

representing an increase of 1.6 percent, or 1,311 MMT CO2

Eq. Soils stored most of the TEC (63 percent), followed by 

live vegetation (26 percent) and DOM (10 percent). Over the 

10-year period, 400 MMT CO2 Eq. was sequestered in live 

vegetation, 478 MMT CO2 Eq. was sequestered in soils, and 

433 MMT CO2 Eq. was added to DOM pools. Average carbon 

storage in live vegetation and soils in Alaska was estimated 

at 131,675 MMT CO2 Eq., with 92 percent stored in soils 

(120,618 MMT CO2 Eq.) and 8 percent stored in live vegetation (11,057 MMT CO2

 Eq.). For the State of Hawaii, we 

estimated 24 MMT CO2 Eq. was stored in live vegetation and 

51 MMT CO2 Eq. was stored in soils. On average, terrestrial 

ecosystems stored a combined 214,554 MMT CO2 Eq. on 

Federal lands between 2005 and 2014 (table 4).

Between 2005 and 2014, Federal lands sequestered an 

average of 343 million metric tons of carbon dioxide equivalent per year (MMT CO2

 Eq./yr) (annual NEP), the difference 

between an average gain through NPP of 2,567 MMT CO2

Eq./yr and an average loss through ecosystem Rh of 2,224 

MMT CO2 Eq./yr. Additional losses of carbon from terrestrial 

ecosystems resulted from wildfire (21 MMT CO2 Eq./yr in 

the CONUS and 46 MMT CO2 Eq./yr in Alaska), logging (43 

MMT CO2 Eq./yr), and other land use and land-use changes 

(39 MMT CO2 Eq./yr). By subtracting the cumulative effects 

of LULC- and disturbance-related CO2 losses to the atmosphere from the NEP, we estimated that ecosystems at the 

national level sequestered CO2 at a mean rate of 195 MMT 

CO2 Eq./yr (NBP). The amount of CO2 sequestered offset 

approximately 15 percent of the CO2 emissions resulting from 

the extraction of fossil fuels on Federal lands and their end-use 

combustion. Federal lands in the CONUS accounted for most 

of the net carbon sink (177 MMT CO2 Eq./yr), and Alaska 

accounted for the remainder.

Carbon sequestration on Federal lands was highly variable over time, owing primarily to interannual variability in 

climate and weather, long-term increases in CO2 fertilization, 

and variability in LULC and disturbances (fig. 4). Between 

2005 and 2014, NPP in the CONUS ranged from 1,841 to 

2,283 MMT CO2 Eq./yr. Over the same period, NBP varied 

between sequestering 475 MMT CO2 Eq./yr and emitting 

carbon to the atmosphere at a rate of 51 MMT CO2 Eq./yr. The 

large variation in the size of the land sink was due, in part, 

to variability in the magnitude of disturbances. For example, 

emissions from wildfire in the CONUS ranged from 3 MMT 

CO2 Eq./yr in 2014 to 44 MMT CO2 Eq./yr in 2012. Over the 

full period of the simulations (1970–2015), variability was 

even higher (fig. 4).

On average, Federal lands in the State of Alaska stored 

131,675 MMT CO2 Eq., with 92 percent stored in soils 

(120,618 MMT CO2 Eq.) and 8 percent stored in live vegetation (11,057 MMT CO2

 Eq.). The amount of carbon stored 

on Federal lands in Alaska was approximately 62 percent of 

the total carbon stored on Federal lands, indicating Alaska’s 

importance in the overall U.S. carbon balance. Nine States 

accounted for over 60 percent of the carbon storage on 

Federal lands in the CONUS (table 5). The largest amount 

was stored in Oregon, followed by California, Idaho, Montana, Nevada, Wyoming, Colorado, Washington, and Utah. 

Oregon stored 10.9 percent (8,985 MMT CO2 Eq.) of the 

Table 4. Carbon stocks and fluxes for Federal lands in the conterminous United States, 2005–14.

[Units are in million metric tons of carbon dioxide equivalent for stocks and million metric tons of carbon dioxide equivalent per year for fluxes. Because of 

rounding, averages may not add to totals shown. Negative values indicate a net carbon sink or sequestration, and positive values indicate a net carbon source 

to the atmosphere or emissions. Total U.S. values can be approximated by adding the average stocks and fluxes in Alaska and Hawaii (table 5) to the values 

presented here. TEC, total ecosystem carbon; Live, storage in live vegetation; DOM, storage in dead organic matter; Soil, storage in soils; NPP, net primary 

productivity; Rh, heterotrophic respiration; NEP, net ecosystems productivity; NBP, net biome productivity; Fire, carbon emissions from wildfire; Harvest, 

carbon loss from forest harvest; Other, carbon loss from land-use and land-cover change and harvested agricultural products. See table 3 and the text for further 

explanation of carbon stocks and fluxes]

Year

Carbon stocks Carbon fluxes

TEC Live DOM Soil NPP Rh NEP NBP Fire Harvest Other

2005 −82,289 −21,270 −8,533 −52,486 −2,283 1,708 −575 −475 11 55 34

2006 −82,322 −21,090 −8,698 −52,534 −1,870 1,723 −147 −29 24 53 40

2007 −82,275 −20,889 −8,779 −52,607 −1,841 1,759 −83 51 34 53 46

2008 −82,353 −20,810 −8,870 −52,673 −1,854 1,661 −193 −75 24 56 38

2009 −82,605 −21,006 −8,875 −52,725 −2,038 1,687 −350 −249 9 59 34

2010 −82,951 −21,310 −8,871 −52,770 −2,174 1,734 −440 −342 9 55 34

2011 −83,170 −21,365 −8,982 −52,823 −1,986 1,686 −301 −219 19 25 38

2012 −83,139 −21,233 −9,033 −52,872 −1,875 1,786 −89 31 44 24 52

2013 −83,334 −21,392 −9,023 −52,919 −2,076 1,783 −293 −195 30 25 43

2014 −83,600 −21,670 −8,966 −52,964 −2,119 1,796 −323 −265 3 25 30

Average −82,804 −21,204 −8,863 −52,737 −2,012 1,732 −279 −177 21 43 39
14 Federal Lands Greenhouse Gas Emissions and Sequestration in the United States: Estimates for 2005–14 Table 5. Average annual carbon stocks and fluxes for onshore Federal lands in the United States, 2005–14.—Continued [Units are in million metric tons of carbon dioxide equivalent for stocks and million metric tons of carbon dioxide equivalent per year for fluxes. Negative values indicate a net carbon sink, and positive values indicate a net carbon source to the atmosphere. TEC, total ecosystem carbon; Live, storage in live vegetation; DOM, storage in dead organic matter; Soil, storage in soils; NPP, net primary productivity; Rh, heterotrophic respiration; NEP, net ecosystems productivity; NBP, net biome productivity; Fire, carbon emissions from wildfire; Harvest, carbon loss from forest harvest; Other, carbon loss from land-use/ land-cover change and harvested agricultural products, —, value not calculated. See table 3 and the text for further explanation of carbon stocks and fluxes.] State Carbon stocks Carbon fluxes TEC Live DOM Soil NPP Rh NEP NBP Fire Harvest Other Alabama −427.6 −201.0 −36.7 −190.0 −20.3 16.6 −3.7 −1.8 0.2 1.3 0.4 Alaska −131,675 −11,057

— −120,618 −552 489 −64 −18 46

—

—

Arizona −2,129.2 −466.4 −207.1 −1,455.7 −55.3 55.5 0.2 1.9 0.7 0.3 0.7Arkansas −773.1 −385.6 −70.9 −316.6 −25.6 20.3 −5.3 −2.5 0.2 1.9 0.8California −8,387.3 −2,822.4 −1,179.7 −4,385.2 −255.9 225.2 −30.7 −14.5 5.1 2.9 8.2Colorado −4,363.0 −1,007.3 −481.9 −2,873.8 −96.3 79.7 −16.6 −13.8 0.4 0.5 1.9Connecticut −5.8 −1.2 −0.5 −4.1 −0.1 0.1 0.0 0.0 0.0 0.0 0.0Delaware −44.7 −4.6 −1.4 −38.6 −0.6 0.5 −0.1 0.0 0.0 0.0 0.0District of Columbia −11.0 −3.3 −1.1 −6.6 −0.3 0.3 0.0 0.0 0.0 0.0 0.0Florida −2,546.9 −267.9 −117.6 −2,161.5 −46.0 42.8 −3.2 −0.1 1.2 0.7 1.1Georgia −1,636.9 −358.5 −83.9 1,194.5 −33.3 29.0 −4.3 −2.2 0.3 1.2 0.6Hawaii −75 −24

— −51 −3 3 <−1

—

—

—

—

Idaho −7,520.5 −1,866.6 −943.1 −4,710.8 −164.2 138.6 −25.6 −14.0 4.3 2.3 4.9Illinois −242.4 −94.5 −22.0 −125.9 −9.0 7.3 −1.7 −0.7 0.0 0.2 0.8Indiana −252.3 −106.8 −25.3 −120.2 −9.7 7.9 −1.8 −1.1 0.0 0.3 0.3Iowa −46.8 −8.1 −2.1 −36.6 −0.9 0.6 −0.3 −0.1 0.0 0.0 0.2Kansas −94.4 −7.3 −2.8 −84.3 −2.7 2.0 −0.7 0.0 0.1 0.0 0.6Kentucky −677.2 −320.2 −65.9 −291.2 −27.6 22.8 −4.8 −3.0 0.0 1.3 0.5Louisiana −513.6 −135.1 −23.4 −355.1 −14.4 12.2 −2.2 −0.5 0.2 1.2 0.3Maine −75.2 −17.9 −5.8 −51.5 −1.7 1.4 −0.3 −0.2 0.0 0.1 0.0Maryland −57.8 −11.4 −3.1 −43.2 −1.2 1.1 −0.2 −0.1 0.0 0.0 0.0Massachusetts −34.7 −4.8 −2.4 −27.5 −0.6 0.5 −0.1 0.0 0.0 0.0 0.0Michigan −3,194.8 −432.6 −255.4 −2,506.8 −44.5 38.9 −5.6 −3.9 0.0 1.2 0.5Minnesota −2,438.7 −312.4 −137.4 −1,988.9 −31.8 28.5 −3.3 −1.8 0.2 0.6 0.6Mississippi −659.5 −279.5 −55.8 −324.2 −31.0 25.9 −5.1 −1.7 0.4 1.9 1.0Missouri −705.1 −319.3 −68.3 −317.5 −20.9 16.8 −4.1 −2.4 0.1 0.7 1.0Montana −6,141.4 −1,768.7 −813.2 −3,559.5 −167.2 143.8 −23.5 −18.9 1.4 2.1 1.2Nebraska −152.7 −17.3 −9.5 −125.9 −3.6 3.1 −0.5 −0.3 0.0 0.0 0.2Nevada −4,882.2 −712.3 −525.7 −3,644.1 −109.2 105.1 −4.1 −0.5 1.0 0.6 2.1
Terrestrial Ecosystems-Associated Carbon Emissions and Sequestration on Federal Lands 15

Table 5.[Units are in million metric tons of carbon dioxide equivalent for stocks and million metric tons of carbon dioxide equivalent per year for fluxes. Negative values indicate a net carbon sink, and positive 

Average annual carbon stocks and fluxes for onshore Federal lands in the United States, 2005–14.—Continued

values indicate a net carbon source to the atmosphere. TEC, total ecosystem carbon; Live, storage in live vegetation; DOM, storage in dead organic matter; Soil, storage in soils; NPP, net primary productivity; Rh, heterotrophic respiration; NEP, net ecosystems productivity; NBP, net biome productivity; Fire, carbon emissions from wildfire; Harvest, carbon loss from forest harvest; Other, carbon loss from land-use/land-cover change and harvested agricultural products, —, value not calculated. See table 3 and the text for further explanation of carbon stocks and fluxes.]

State

Carbon stocks Carbon fluxes

TEC Live DOM Soil NPP Rh NEP NBP Fire Harvest Other

New Hampshire −320.6 −120.2 −39.3 −161.2 −10.0 8.5 −1.5 −1.1 0.0 0.4 0.0

New Jersey −142.0 −16.8 −6.5 −118.8 −1.9 1.7 −0.2 −0.2 0.0 0.0 0.0

New Mexico −2,299.8 −530.6 −265.5 −1,503.7 −64.5 60.8 −3.7 −2.1 0.7 0.3 0.6

New York −96.7 −23.1 −6.5 −67.1 −2.0 1.6 −0.3 −0.2 0.0 0.0 0.1

North Carolina −2,906.8 −519.1 −123.9 −2,263.8 −46.2 39.1 −7.1 −4.5 0.1 1.8 0.7

North Dakota −491.1 −35.2 −18.6 −437.4 −12.8 9.9 −2.9 −1.8 0.0 0.0 1.0

Ohio −249.5 −116.2 −22.5 −110.8 −9.4 7.6 −1.8 −0.9 0.0 0.5 0.4

Oklahoma −199.3 −55.5 −12.2 −131.5 −6.7 5.6 −1.1 −0.3 0.0 0.4 0.3

Oregon −8,985.2 −2,685.8 −1,054.4 −5,245.0 −198.9 159.5 −39.4 −29.6 1.3 6.7 1.8

Pennsylvania −247.9 −114.6 −24.8 −108.5 −8.2 6.6 −1.6 −1.2 0.0 0.3 0.1

Rhode Island −16.0 −5.2 −1.9 −9.0 −0.4 0.4 −0.1 0.0 0.0 0.0 0.0

South Carolina −532.8 −187.3 −39.1 −306.5 −18.8 15.9 −2.9 −1.1 0.2 1.2 0.4

South Dakota −596.5 −102.0 −59.6 −434.9 −17.0 14.0 −3.1 −2.5 0.0 0.1 0.4

Tennessee −586.9 −283.6 −58.8 −244.5 −23.2 19.8 −3.4 −2.3 0.1 0.6 0.5

Texas −786.4 −199.1 −39.2 −548.0 −22.6 19.6 −3.0 −0.7 0.2 1.2 0.9

Utah −3,581.9 −706.5 −358.4 −2,517.1 −82.8 72.0 −10.8 −8.6 0.5 0.4 1.3

Vermont −375.6 −94.9 −32.2 −248.5 −8.2 6.9 −1.3 −0.9 0.0 0.4 0.1

Virginia −1,255.8 −513.1 −118.2 −624.5 −45.9 39.4 −6.5 −4.2 0.1 1.4 0.7

Washington −4,248.7 −1,703.2 −582.4 −1,963.0 −104.2 80.2 −24.0 −18.2 0.9 4.2 0.7

West Virginia −651.8 −279.1 −69.6 −303.1 −23.7 20.1 −3.6 −2.5 0.0 0.9 0.2

Wisconsin −1,405.1 −163.1 −75.9 −1,166.1 −16.6 14.9 −1.7 −1.1 0.0 0.4 0.2

Wyoming −4,812.2 −816.0 −711.1 −3,285.1 −113.8 101.7 −12.1 −10.4 0.5 0.6 0.6

United States −214,554 −32,285 −8,863 −173,406 −2,567 2,224 −343 −195 67 43 39
16 Federal Lands Greenhouse Gas Emissions and Sequestration in the United States: Estimates for 2005–14 Carbon flux, in million metric tons of carbon dioxide per year

Year

Carbon sequestration

Carbon emission

0

-500

-1,000

-1,500

-2,000

1990 2000 2010

Net primary productivity

Net ecosystems productivity

Net biome productivity

EXPLANATION

Figure 4. Graph showing estimates of annual rates of net primary productivity, net ecosystems productivity, and net biome productivity 

for the conterminous United States, 1985–2015. Negative values denote a net carbon sink or sequestration, and positive values denote 

a net carbon source to the atmosphere or emissions. Solid lines represent actual values, dashed lines are linear regression trend lines, 

and color bands indicate the standard error from those trend lines.

total carbon storage on Federal lands in the CONUS and 

accounted for 7.7 percent of the Federal land area. Conversely, Nevada accounted for the largest proportion of 

CONUS Federal land area (13.7 percent) but stored only 

5.9 percent of the total carbon (4,882 MMT CO2 Eq.). Of the 

20 States with the largest Federal land area, the largest carbon 

storage densities were in North Carolina (1,736 metric tons of 

carbon dioxide equivalent per hectare [t CO2 Eq./ha]), Florida 

(1,438 t CO2 Eq./ha), and Michigan (1,416 t CO2 Eq./ha), 

owing primarily to the formation of deep, organically rich 

peat soils.

Aside from Alaska (552 MMT CO2 Eq./yr), California 

had the highest rate of NPP, averaging 256 MMT CO2 Eq./yr. 

Nevada, which has the largest Federal land area in the 

CONUS, averaged 109 MMT CO2 Eq./yr in NPP. The difference in mean annual carbon uptake can be attributed primarily 

to the proportion of forest lands found in California compared 

with Nevada. Forests remove carbon from the atmosphere at 

a much higher rate than regions dominated by grasslands and 

shrublands. Of the States with more than 5 million hectares 

of Federal land area, Washington had the highest rate of 

carbon uptake, averaging 19 metric tons of carbon dioxide 

equivalent per hectare per year (t CO2 Eq./ha/yr). The highest 

uptake rate overall was found in Alabama, which averaged 

32 t CO2 Eq./ha/yr.

When ecosystem respiration, LULC, and disturbances 

were considered, Oregon was the largest net sink (highest NBP) 

of carbon on Federal lands at a rate of 30 MMT CO2 Eq./yr. 
Net Emissions and Sequestration Results 17

Montana sequestered 19 MMT CO2 Eq./yr. Alaska and 

Washington each sequestered 18 MMT CO2 Eq./yr, followed by California (15 MMT CO2

 Eq./yr), Idaho 

(14 MMT CO2 Eq./yr), Colorado (14 MMT CO2 Eq./yr), and 

Wyoming (10 MMT CO2 Eq./yr). Alaska had the largest mean 

annual carbon emissions from wildfire at 46 MMT CO2 Eq./yr, 

followed by California and Idaho, which averaged 5 and 

4 MMT CO2 Eq./yr, respectively. Montana, Oregon, Florida, 

and Nevada all averaged 1 to 2 MMT CO2 Eq./yr of fire 

emissions. The largest logging related carbon losses were 

found in Oregon and Washington, which averaged 7 and 

4 MMT CO2 Eq./yr, respectively.

Net Emissions and Sequestration 

Results

Combining the fossil fuel extraction and combustion 

emissions with the ecosystems emissions and sequestration estimates provides an informative summary result that 

includes both anthropogenic emissions and sequestration by 

ecosystems on Federal lands. This result is the net emissions 

value and is the sum of the total fossil fuel CO2 emission value 

and the NBP, which is negative if carbon is stored and positive 

if carbon is emitted. The NBP reflects the absolute change in 

carbon stored within ecosystems on an annual basis. A positive net emission result indicates that emissions are greater 

than sequestration, whereas a negative value indicates that 

sequestration is greater than emissions. Ecosystems data were 

calculated for the period 1970–2015, but only the results for 

2005–14 are provided in this report for comparison with fossil 

fuel-associated emissions estimates. In addition, sequestration data were not available for the Federal offshore areas, so 

net emissions values are not available for the offshore Pacific 

and offshore Gulf areas. The Hawaii sequestration values are 

not calculable on an annual level and are therefore excluded 

from the net emissions results. The net emissions results for 

2005–14 are provided in table 6.

Annual net emissions data for the United States show 

variations that reflect the variation in the ecosystems NBP 

data. These variations are described in the terrestrial ecosystems-associated carbon emissions and sequestration “Results” 

section. In general, fossil fuel-associated emissions data show 

increasing or decreasing long-term trends but not significant 

annual variation. Whereas most major fossil fuel-producing 

States have positive net emissions, some States with lesser 

production alternate between positive and negative net emissions because ecosystem NBP (sequestration) values may be 

larger than the State’s fossil fuel-associated emissions.

Table 6. Net emissions for Federal lands in the United States, 2005–14.—Continued

[All units are in million metric tons of carbon dioxide equivalent per year. Positive values indicate a net carbon emission, and negative values indicate a net 

carbon sequestration. Annual net biome productivity was not available for Hawaii and the offshore areas; therefore, U.S. total net emissions values are not 

included in this table. —, values were not calculated due to unavailability of annual terrestrial ecosystems-associated carbon emissions and sequestration]

State 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

Alabama 0.2 2.9 5.6 0.9 −0.7 2.7 2.7 2.6 −2.6 −2.5

Alaska –14.1 –14.6 –15.0 –14.9 –15.7 –16.1 –16.6 –16.8 –16.7 –16.5

Arizona −28.8 23.9 24.3 −8.6 0 −15.6 14.8 14.4 −13.2 7.5

Arkansas 1.6 1.2 −0.9 −5 −4.2 0.9 −1.2 −0.9 −3 −5.3

California −82.8 22.9 55.4 34.9 −22.8 −69 −24 35.2 13.4 28.6

Colorado 29.3 34.4 32.8 52.8 37.1 52.1 43.2 68.7 30.7 12.1

Connecticut 0 0 0 0 0 0 0 0 0 0.0

Delaware −0.1 −0.1 0 0 0 0 −0.1 −0.1 −0.1 0.0

District of Columbia −0.1 0 0 0 −0.1 0 0 0 0 −0.1

Florida −1.6 5.4 5.4 −2.6 1.9 −3.2 3.1 −1.6 −1.8 −6.0

Georgia −2.5 −1.2 2.7 −2.7 −5.9 −2.3 −0.4 −2.5 −4 −3.6

Hawaii — — — — — — — — — —

Idaho −44.2 −7.7 7.1 0 −33.3 −38.3 −14.3 13.3 −1.3 −21.2

Illinois −0.1 −1.2 0.1 −1.7 −1.1 0.6 −2.5 0.5 −0.9 −0.8

Indiana −0.3 −1.8 −0.3 −2 −1.1 0.4 −2.2 −0.9 −1.3 −1.4

Iowa −0.1 −0.1 −0.1 −0.1 −0.1 −0.1 −0.1 0 0 −0.1

Kansas 0.4 0.9 0.4 0.3 0.2 0.5 0.8 0.5 0.2 0.4

Kentucky −0.7 1 3.9 −0.7 −4.4 −0.5 −8 −5.4 −5.9 −4.3
18 Federal Lands Greenhouse Gas Emissions and Sequestration in the United States: Estimates for 2005–14

Table 6. Net emissions for Federal lands in the United States, 2005–14.—Continued

[All units are in million metric tons of carbon dioxide equivalent per year. Positive values indicate a net carbon emission, and negative values indicate a net 

carbon sequestration. Annual net biome productivity was not available for Hawaii and the offshore areas; therefore, U.S. total net emissions values are not 

included in this table. —, values were not calculated due to unavailability of annual terrestrial ecosystems-associated carbon emissions and sequestration]

State 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

Louisiana 115.4 108.7 112.2 84.4 87.5 83 73.5 63 59.8 53.4

Maine −0.2 −0.3 −0.2 −0.1 −0.2 −0.2 −0.2 −0.2 −0.2 −0.2

Maryland −0.1 −0.1 0 −0.1 −0.1 0 −0.1 −0.1 −0.1 −0.2

Massachusetts 0 −0.1 0 0 −0.1 0 0 −0.1 0 0.0

Michigan 2.7 −2.9 −1.4 −1.4 −6.5 −0.7 −8.2 −7.1 −5.3 −6.6

Minnesota −1.9 −0.7 0.5 −2.5 −3 −2.5 −1.6 −2 −1 −3.1

Mississippi −0.5 3.3 1.8 −1.8 −3.5 −0.5 −2.9 −4.1 −4.2 −3.5

Missouri −0.9 −1.6 −1.2 −5 −4.6 −0.9 −2.8 −0.2 −4.5 −1.8

Montana 15.6 44.4 41 35.3 37.9 4.2 22.3 34.1 23.7 20.2

Nebraska −0.5 0.7 0.1 −0.7 −1.1 −0.9 −0.9 1.3 0.5 −1.2

Nevada −61.3 17.8 43.7 20.6 −18.3 −16.7 0.8 26.8 −1.9 −14.7

New Hampshire −0.6 −1.2 −2.2 −0.4 −1 −1.2 −1.1 −1.2 −1.2 −1.1

New Jersey −0.1 −0.2 −0.2 −0.1 −0.2 0 −0.2 −0.4 −0.4 −0.2

New Mexico 68 66.6 67.6 63.3 71 58.7 72.5 79.7 63.5 68.6

New York −0.1 −0.3 −0.1 −0.2 −0.3 −0.1 −0.3 −0.3 −0.3 −0.3

North Carolina −3.3 −7 −4.9 −4.6 −7.9 −3.1 −5 −6.4 0.4 −3.6

North Dakota 2.5 7.7 9.2 8.3 2.7 0.2 7 14.5 12 12.4

Offshore Gulf — — — — — — — — — —

Offshore Pacific — — — — — — — — — —

Ohio 0.2 −0.9 0.5 −1.1 −1 0.1 −2.5 −1.5 −1.2 −0.6

Oklahoma 1.9 2.4 1 1 0.9 2 2.7 1.4 0.9 0.8

Oregon −57.7 −13.4 −23 −8.4 −20.7 −48 −38.2 −22.7 −31.5 −32.8

Pennsylvania −0.3 −0.8 −1.4 −1.1 −0.9 −0.2 −2.3 −2.2 −1.3 −1.5

Rhode Island −0.1 0 0 0 −0.1 −0.1 0 0 0 −0.1

South Carolina −1.3 −0.7 1.8 −0.1 −2 −0.6 −1 −0.8 −4.5 −2.0

South Dakota −0.5 2.2 1.4 −6.1 −3.7 −7.3 −3.5 6 −3 −9.8

Tennessee −2.1 −1.3 1.4 −0.6 −4.6 −1.9 −4.6 −4 −2.7 −2.4

Texas 29.5 28.3 21.1 17.9 17.8 13.6 16 9.7 6.6 3.2

Utah 4.8 37.1 50.7 55 31.6 28.5 14.4 55.3 38.8 25.2

Vermont −0.1 −0.4 −1.3 −0.1 −0.8 −1.2 −0.1 −1.7 −1.5 −1.5

Virginia −2.2 −0.6 −1.9 −0.9 −4.3 −3.1 −10.4 −7 −6.3 −5.1

Washington −30.1 −8.9 −15.4 −15.1 −13.2 −27.7 −16.2 −14.5 −24 −16.7

West Virginia −0.3 −2 −1.3 −4.1 −2.5 −0.4 −5.7 −4.7 −2.3 −1.9

Wisconsin 0.4 −0.7 0.8 −1.5 −1.5 −0.4 −2.2 −2.1 −1.8 −2.2

Wyoming 736 789.6 818.2 871 814.9 836.3 824.2 783.3 708.2 701.5
References Cited 19

Conclusions

The USGS has produced estimates of fossil fuel-associated greenhouse gas emissions and terrestrial ecosystemassociated carbon emissions and sequestration for the Federal 

lands of the United States for 2005–14. Emissions associated 

with fossil fuel extraction and end-use combustion parallel 

production levels. States with significant fossil fuel production 

from Federal lands generally have higher estimated greenhouse gas emissions. Some States are significant producers of 

fossil fuels from non-Federal lands (such as State and private 

lands), and presumably have high emissions as well, but if the 

production is not from Federal lands, those emissions are not 

estimated here. Estimates of ecosystem carbon sequestration 

on Federal lands show that the amounts are highly variable 

owing to climate and weather, wildfires, land use and landuse changes, and other factors. States with the largest forests 

or Federal land holdings do not necessarily have the most 

significant ecosystem sequestration because soils retain more 

carbon than living matter does and ecosystems release carbon 

as well as store it. These factors highlight the complexity of 

the ecosystem sequestration calculation that is accounted for 

in the estimated results. The combined or net emission values 

included in this report are an informative, though simplistic, 

way of combining the two estimates.

These results are not intended or appropriate for ranking or comparing the States for many reasons. Firstly, the 

proportion of Federal lands to total lands varies considerably 

across each State. Secondly, these estimates report fossil 

fuel-associated emissions by the State of origin rather than the 

State where the emissions occurred. The data required to track 

all fossil fuels to their location of eventual end-use combustion are not available because of the structure of the United 

States’ energy and industrial infrastructure. Thirdly, this study 

addresses the Federal lands-based scope that was given to the 

USGS; it was not designed to produce results for comparing 

States.

These USGS estimates provide a first-of-its-kind accounting for the emissions associated with fossil fuel extraction on 

Federal lands, the end-use combustion of those fuels, and the 

ecosystems sequestration and emissions of carbon on Federal 

lands. This information may provide context for future energy 

decisions, as well as serve as a reference to compare future 

changes in greenhouse gas emissions and carbon sequestration 

on Federal lands.

References Cited

Bureau of Ocean Energy Management, 2011, BOEM Pacific 

active oil and gas platforms: Bureau of Ocean Energy Management vector digital data, accessed March 21, 2017, at 

https://www.boem.gov/PC-plat.zip.

Bureau of Safety and Environmental Enforcement, 2014, 

Outer Continental Shelf oil and natural gas platforms—Gulf 

of Mexico region NAD 27: Bureau of Safety and Environmental Enforcement vector digital data, accessed March 

21, 2017, at https://www.data.boem.gov/Mapping/Files/

platform.zip.

Foley, J.A., Prentice, I.C., Ramunkutty, N., Levis, S., Pollard, D., Sitch, S., and Haxeltine, A., 1996, An integrated 

biosphere model of land surface processes, terrestrial carbon 

balance, and vegetation dynamics: Global Biogeochemistry 

Cycles, v. 10, no. 4, p. 603–628. [Also available at https://

doi.org/10.1029/96GB02692.]

Franklin, P., Scheehle, E., Collings, R.C., Coté, M.M., and 

Pilcher, R.C., 2004, Proposed methodology for estimating 

emission inventories from abandoned coal mines—Prepared 

for the 2006 IPCC [Intergovernmental Panel on Climate 

Change] National Greenhouse Gas Inventories Guidelines, 

Fourth Authors/Experts Meeting, Energy—Methane Emissions for Coal Mining and Handling, Arusha, Tanzania, 

[Sept. 28–30, 2004]: U.S. Environmental Protection Agency 

white paper, variously paged, accessed May 2, 2017, 

at https://www.epa.gov/sites/production/files/2016-03/

documents/methodology_abandoned_coalmines.pdf.

Genet, H., McGuire, A.D., Barrett, K., Breen, A., Euskirchen, 

E.S., Johnstone, J.F., Kasischke, E.S., Melvin, A.M., Bennett, A., Mack, M.C., Rupp, T.S., Schuur, E.A.G., Turetsky, 

M.R., and Yuan, F., 2013, Modeling the effects of fire 

severity and climate warming on active layer thickness and 

soil carbon storage of black spruce forests across the landscape in interior Alaska: Environmental Research Letters, 

v. 8, no. 4, letter 045016, 13 p., accessed July 25, 2018, at 

http://dx.doi.org/10.1088/1748-9326/8/4/045016.

Hijmans, R.J., and van Etten, J., 2012, Raster—Geographic 

analysis and modeling with raster data: R package version 

2.0–12 (September 2, 2012), at http://CRAN.R-project.org/

package=raster.

Intergovernmental Panel on Climate Change, 2006, 2006 

IPCC guidelines for national greenhouse gas inventories 

[Prepared by the National Greenhouse Gas Inventories Programme; Eggleston, H.S., Buendia, L., Miwa, K., Ngara, T., 

and Tanabe, K., eds.]: Hayama, Japan, Institute for Global 

Environmental Strategies, 5 v., accessed May 20, 2016, at 

http://www.ipcc-nggip.iges.or.jp/public/2006gl/index.html.

Intergovernmental Panel on Climate Change, 2007, Climate 

change 2007—The physical science basis—Contribution 

of Working Group I to the fourth assessment report of the 

Intergovernmental Panel on Climate Change [Solomon, 

S., Qin, D., Manning, M., Marquis, M., Averyt, K., Tignor, 

M.M.B., Miller, H.L., Jr., and Chen, Z., eds.]: New York, 

Cambridge University Press, 996 p. [Also available at 

https://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4_

wg1_full_report.pdf.]
20 Federal Lands Greenhouse Gas Emissions and Sequestration in the United States: Estimates for 2005–14

Jacobi, J.D., Price, J.P., Fortini, L.B., Gon, S.M., III, and 

Berkowitz, P., 2017, Baseline land cover, chap. 2 of Selmants, P.C., Giardina, C.P., Jacobi, J.D., and Zhu, Z., eds., 

Baseline and projected future carbon storage and carbon 

fluxes in ecosystems of Hawai‘i: U.S. Geological Survey Professional Paper 1834, p. 9–20. [Also available at 

https://doi.org/10.3133/pp1834.]

Kucharik, C.J., Foley, J.A., Delire, C., Fisher, V.A., Coe, M.T., 

Lenters, J.D., Young-Molling, C., Ramankutty, N., Norman, 

J.M., and Gower, S.T., 2000, Testing the performance of a 

dynamic global ecosystem model—Water balance, carbon 

balance, and vegetation structure: Global Biogeochemical Cycles, v. 14, no. 3, p. 795–825. [Also available at 

https://doi.org/10.1029/1999GB001138.]

Liu, J., Price, D.T., and Chen, J.M., 2005, Nitrogen controls 

on ecosystem carbon sequestration—A model implementation and application to Saskatchewan, Canada: Ecological 

Modelling, v. 186, no. 2, p. 178–195. [Also available at 

https://doi.org/10.1016/j.ecolmodel.2005.01.036.]

Liu, J., Sleeter, B.M., Zhu, Z., Heath, L.S., Tan, Z., Wilson, 

T.S., Sherba, J., and Zhou, D., 2016, Estimating carbon 

sequestration in the Piedmont ecoregion of the United States 

from 1971 to 2010: Carbon Balance and Management, v. 

11, 13 p. [Also available at https://doi.org/10.1186/s13021-

016-0052-y.]

Liu, J., Vogelmann, J.E., Zhu, Z., Key, C.H., Sleeter, B.M., 

Price, D.T., Chen, J.M., Cochrane, M.A., Eidenshink, J.C., 

Howard, S.M., Bliss, N.B., and Jiang, H., 2011, Estimating 

California ecosystem carbon change using process model 

and land cover disturbance data—1951–2000: Ecological 

Modelling, v. 222, no. 14, p. 2333–2341. [Also available at 

https://doi.org/10.1016/j.ecolmodel.2011.03.042.]

Merrill, M.D., Sleeter, B.M., Freeman, P.A., Liu, J., Warwick, 

P.D., and Reed, B.C., 2018, Federal lands greenhouse gas 

emissions and sequestration—Estimates 2005–14—Data 

release: U.S. Geological Survey data release, https://doi.

org/10.5066/F7KH0MK4.

Minerals Management Service, 2006a, Digital Offshore 

Cadastre (DOC)—Gulf of Mexico Federal Outer Continental Shelf (OCS) administrative boundaries (preliminary): Minerals Management Service vector digital 

data, accessed March 21, 2017, at http://www.mms.gov/

ld/lateral.htm. [Dataset moved by time of publication; 

accessed August 14, 2018, at https://www.boem.gov/

Administrative-Boundaries/.]

Minerals Management Service, 2006b, Digital Offshore 

Cadastre (DOC)—Pacific Federal Outer Continental Shelf 

(OCS) administrative boundaries (preliminary): Minerals 

Management Service vector digital data, accessed March 

21, 2017, at http://www.mms.gov/ld/lateral.htm. [Dataset 

moved by time of publication; accessed August 14, 2018, at 

https://www.boem.gov/Administrative-Boundaries/.]

R Core Team, 2013, R—A language and environment for 

statistical computing: Vienna, Austria, R Foundation for 

Statistical Computing, at http://www.R-project.org/.

Selmants, P.C., Giardina, C.P., Jacobi, J.D., and Zhu, Z., eds., 

2017, Baseline and projected future carbon storage and 

carbon fluxes in ecosystems of Hawai‘i: U.S. Geological 

Survey Professional Paper 1834, 134 p.. [Also available at 

https://doi.org/10.3133/pp1834.]

Sleeter, B.M., Liu, J., Daniel, C.J., Hawbaker, T.J., Wilson, 

T.S., Fortini, L.B., Jacobi, J.D., Selmants, P.C., Giardina, 

C.P., Litton, C.M., and Hughes, R.F., 2017, Projected future 

carbon storage and carbon fluxes in terrestrial ecosystems of 

Hawai‘i from changes in climate, land use, and disturbance, 

chap. 8 of Selmants, P.C., Giardina, C.P., Jacobi, J.D., and 

Zhu, Z., eds., Baseline and projected future carbon storage 

and carbon fluxes in ecosystems of Hawai‘i: U.S. Geological Survey Professional Paper 1834, p. 107–128. [Also 

available at https://doi.org/10.3133/pp1834.]

U.S. Energy Information Administration, 2015a, Sales of 

fossil fuels produced from Federal and Indian lands, FY 

2003 through FY 2014: Washington, D.C., U.S. Energy 

Information Administration, 32 p. [Also available at 

https://www.eia.gov/analysis/requests/federallands/pdf/

eia-federallandsales.pdf.]

U.S. Energy Information Administration, 2015b, Table 1, 

U.S. supply, disposition, and ending stocks of crude oil and 

petroleum products, 2014, in Petroleum supply annual, v. 

1: U.S. Energy Information Administration, 1 p., accessed 

April 12, 2017, at https://www.eia.gov/petroleum/supply/

annual/volume1/archive/2014/psa_volume1_2014.cfm.

U.S. Energy Information Administration, 2015c, Table 23, 

percent yield of petroleum products by PAD and refining districts, 2014, in Petroleum supply annual, v. 1: U.S. 

Energy Information Administration, 1 p., accessed April 

12, 2017, at https://www.eia.gov/petroleum/supply/annual/

volume1/archive/2014/psa_volume1_2014.cfm.

U.S. Energy Information Administration, 2016a, Annual coal 

distribution report 2014, by coal origin State: U.S. Energy 

Information Administration, 47 p., accessed February 

13, 2017, at http://www.eia.gov/coal/distribution/annual/

archive/2014/o_14state.pdf.
References Cited 21

U.S. Energy Information Administration, 2016b, Monthly 

energy review, July 2016: U.S. Energy Information 

Administration [report] DOE/EIA–0035 (2016/07), 224 

p., accessed September 22, 2016, at http://www.eia.gov/

totalenergy/data/monthly.

U.S. Environmental Protection Agency, 2004, Methane 

emissions from abandoned coal mines in the United 

States—Emissions inventory methodology and 1990–2002 

emissions estimates: U.S. Environmental Protection 

Agency [report] EPA 430–R–04–001, 54 p. [Also avail-

able at https://nepis.epa.gov/Exe/ZyPDF.cgi/600004JM.

PDF?Dockey=600004JM.PDF.]

U.S. Environmental Protection Agency, 2015, Inventory of 

U.S. greenhouse gas emissions and sinks 1990–2013—

Revision to offshore platform emissions estimate: Wash-

ington, D.C., U.S. Environmental Protection Agency, 

3 p., accessed April 5, 2017, at https://www.epa.gov/

sites/production/files/2015-12/documents/revisionoffshoreplatforms-emissions-estimate-4-10-2015.pdf.

U.S. Environmental Protection Agency, 2016a, Annexes 

to the inventory of U.S. GHG emissions and sinks [—

to accompany U.S. Environmental Protection Agency, 

Inventory of U.S. greenhouse gas emissions and sinks—

1990–2014, [report] EPA 430–R–16–002]: U.S. Envi-

ronmental Protection Agency, 494 p., accessed April 5, 

2017, at https://www.epa.gov/ghgemissions/inventory-usgreenhouse-gas-emissions-and-sinks-1990-2014.

U.S. Environmental Protection Agency, 2016b, Inventory of 

U.S. greenhouse gas emissions and sinks—1990–2014: 

U.S. Environmental Protection Agency [report] EPA 

430–R–16–002, variously paged, plus additional online 

data tables, accessed April 5, 2017, at https://www.epa.gov/

ghgemissions/inventory-us-greenhouse-gas-emissions-andsinks-1990-2014.

U.S. Geological Survey, 2016, Protected Areas Database of 

the United States, version 1.4: U.S. Geological Survey Gap 

Analysis Program database, accessed September 16, 2017, 

at http://gapanalysis.usgs.gov/padus/.

Zhu, Q., Liu, J., Peng, C., Chen, H., Fang, X., Jiang, H., Yang, 

G., Zhu, D., Wang, W., and Zhou, X., 2014, Modelling 

methane emissions from natural wetlands by development 

and application of the TRIPLEX-GHG model: Geoscientific 

Model Development, v. 7, p. 981–999. [Also available at 

https://doi.org/10.5194/gmd-7-981-2014.]

Zhu, Z., and McGuire, A.D., eds., 2016, Baseline and 

projected future carbon storage and greenhouse-gas 

fluxes in ecosystems of Alaska: U.S. Geological Survey 

Professional Paper 1826, 196 p. [Also available at 

https://doi.org/10.3133/pp1826.]
22 Federal Lands Greenhouse Gas Emissions and Carbon Sequestration in the United States: Estimates for 2005–14

Glossary

[See also table 3, “Explanation of carbon stock and flux terms from the terrestrial ecosystem sequestration 

calculations”]

abandoned coal mine emissions Emissions of methane, such as from offgassing 

or desorption, occurring after the cessation 

of extraction activities at a surface or underground coal mine.

active coal mine emissions Emissions of 

methane from ongoing extraction activities at 

a surface or underground coal mine.

combustion The process of burning fossil 

fuels to release energy.

emission factor A value that describes the 

greenhouse gas content of a fuel used in a particular sector of the economy or that indicates 

the amount of greenhouse gas emitted by a 

particular extraction activity.

estimated emissions Calculated estimates 

of greenhouse gases released by activities in 

various sectors of the economy.

estimated uptake Calculated estimates of 

carbon (represented in equivalent amounts of 

carbon dioxide, a greenhouse gas) sequestered 

or stored in plants and other organisms.

exported fuels emissions Emissions of 

greenhouse gases from coal, natural gas, and 

liquid petroleum products exported to other 

countries.

Federal lands Lands that are administered 

by various agencies of the U.S. Federal 

Government.

Federal offshore Areas seaward of State 

waters boundaries that are under the administration of the Bureau of Ocean Energy 

Management. Examples include the offshore 

Pacific area and offshore Gulf area.

fossil fuel A natural hydrocarbon material that is extracted and then combusted to 

release energy. Examples include coal, natural 

gas, crude oil, and various liquid petroleum 

products.

greenhouse gas Gases that cause the 

amount of solar thermal energy retained by 

the Earth’s atmosphere to increase when their 

concentrations increase. The greenhouse gases 

discussed in this report are carbon dioxide 

(CO2), methane (CH4), and nitrous oxide 

(N2O).

mine abandonment The process by which 

an underground coal mine is closed. Examples 

include sealing, venting, and flooding. The 

abandonment process determines the emission factor used to calculate the amount of 

methane gas released from the abandoned 

mine over time.

mobile combustion emissions Emissions of 

greenhouse gases from fossil fuel combustion 

in the transportation sector.

petroleum and natural gas systems emissions Emissions of greenhouse gases from 

ongoing extraction activities and product 

transportation in the petroleum and natural 

gas industries.

stationary combustion emissions Emissions 

of greenhouse gases produced during the 

combustion of fossil fuels in all nontransportation sectors, including electricity generation, 

industrial feedstocks, and residential and commercial heating.
Appendixes 1–2 
24 Federal Lands Greenhouse Gas Emissions and Carbon Sequestration in the United States: Estimates for 2005–14

Appendix 1. Detailed Methods: Fossil Fuel-Associated Emissions of 

Greenhouse Gases from Federal Lands

Introduction

The methods described in this appendix are either very 

similar to those described in, or use outputs from, the U.S. 

Environmental Protection Agency (EPA) Inventory of U.S. 

Greenhouse Gas Emissions and Sinks (hereafter EPA Inventory; U.S. Environmental Protection Agency, 2016b). The 

methods were modified to suit the goals of this U.S. Geological 

Survey (USGS) study. Therefore, the EPA Inventory and associated annexes (U.S. Environmental Protection Agency, 2016a, 

b) are the best sources for the general methods described here. 

This description highlights general steps, sources for inputs, 

and areas where the USGS method differs from that of the EPA 

Inventory. Tables 1–1 through 1–6 include summary information on the sources for all input data used.

Stationary Combustion Emissions

Estimates of stationary combustion emissions for coal 

were calculated by using total State production volumes 

obtained from the Office of Natural Resources Revenue 

(ONRR) of the U.S. Department of the Interior via Memorandum of Agreement MOA16–5285. The production volumes 

were reduced to account for the coal that was exported in each 

year. The amount of coal produced on Federal lands and then 

exported was estimated by using the ratio of total State coal 

(private, State, and Federal combined) exported internationally to total State coal produced (U.S. Energy Information 

Administration, 2016a). Once the exports were subtracted 

from State production, the resulting amount was apportioned 

to the various sectors where coal is used domestically. For all 

coal sectors (electricity generation, commercial, industrial, and 

coking coal production), a basic process was followed. The 

State production minus exports was multiplied by State-level 

sector proportions that determined the “sector coal,” or how 

much of the total coal was used in each sector (U.S. Energy 

Information Administration, 2016a). In the final step, the sector coal amounts were multiplied by carbon dioxide (CO2

), 

methane (CH4), and nitrous oxide (N2O) emission factors to 

estimate the amounts of gases emitted. The emission factors 

used are specific to each sector and were reported by the EPA 

(U.S. Environmental Protection Agency, 2014) and references 

therein.

The method used to estimate emissions for natural gas 

follows the same general method described above for coal. 

The ONRR production data were the starting point. Data 

on dry gas production and exports are from the U.S. Energy 

Information Administration (EIA) (U.S. Energy Information 

Administration, 2016b). Sector proportions for industrial nonfuel use are from the EIA Manufacturing Energy Consumption Survey (U.S. Energy Information Administration, 2013), 

which is released every 5 years. All remaining natural gas was 

apportioned to a stationary combustion fuel-use sector. The 

EPA provided one set of emission factors for the stationary 

combustion of natural gas (U.S. Environmental Protection 

Agency, 2014). The amount of industrial nonfuel natural gas 

was reduced by a storage factor to account for the proportion 

of the natural gas that served as feedstock rather than being 

combusted (U.S. Environmental Protection Agency, 2016a).

Estimation of emissions from the combustion of various petroleum products started with crude oil production data 

provided by the ONRR. The crude oil volumes were converted 

to total State production volumes of refined products using 

national-level refining data (U.S. Energy Information Administration, 2015b). State-level refining information is not available for liquid fuels owing to the comingled nature of liquid 

fuel transportation in pipelines. Exports were subtracted from 

the total volumes (U.S. Energy Information Administration, 

2015a), and the resulting volumes were apportioned to end-use 

sectors by using sector proportion data obtained from the EIA 

Monthly Energy Review (U.S. Energy Information Administration, 2016b). Lastly, the sector-specific petroleum product 

volumes were multiplied by the CO2, CH4, and N2O emission 

factors for each sector from the EPA (U.S. Environmental Protection Agency, 2014). See table 1–1 for the inputs and sources 

mentioned in this section.

Mobile Sector Combustion Emissions

Estimates of emissions associated with combustion from 

mobile (transportation) uses were generated from ratios of 

emissions to fuel volumes combusted as reported by the EPA 

Inventory (U.S. Environmental Protection Agency, 2016b). 

Crude oil production volumes from the Federal lands in each 

State were obtained from the ONRR. The crude oil data were 

partitioned into estimated petroleum products (for example, 

gasoline, diesel oil, jet fuel, lubricants) on the basis of national 

refining products data (U.S. Energy Information Administration, 2015b). Export amounts were obtained from the EIA 

Petroleum Supply Annual (U.S. Energy Information Administration, 2015a). It was assumed that the national export ratios 

are the same as the export ratios for petroleum produced from 

Federal lands. Sector use information for each fuel was used to 

determine the proportions that were consumed in mobile uses 

(U.S. Energy Information Administration, 2016b).

The ratios of the U.S. annual emissions of CO2, CH4, and 

N2O (U.S. Environmental Protection Agency, 2016b) to the 

annual mobile fuel consumption (U.S. Environmental Protection Agency, 2016a) provided values of emissions per gallon 

of fuel consumed (by gas and type of fuel). These values were 

multiplied by the volumes of fuels sourced from Federal lands 

and consumed domestically to estimate the emissions for each 
Appendix 1 25

fuel. This method reasonably assumes that the national emissions ratios are representative of the emissions ratios expected 

for fuels from Federal lands. See table 1–2 for the inputs and 

sources mentioned in this section.

Petroleum and Natural Gas Systems Emissions

Total national emissions from petroleum and natural 

gas systems (CO2 and CH4 emitted from production through 

distribution) (U.S. Environmental Protection Agency, 2016b) 

were divided by the national oil and natural gas well counts 

(U.S. Environmental Protection Agency, 2017a, b), resulting 

in ratios of CO2 and CH4 emissions per well for petroleum and 

natural gas systems. These national ratios were then multiplied by the numbers of Federal producing oil and gas wells 

in a State to estimate emissions. For the years included in this 

study (2005–14), State-level Federal lands well counts were 

available for 2014 only (Bureau of Land Management, written 

commun., 2016). To generate Federal lands well counts for 

other years, the 2014 State Federal lands wells were divided 

by the total State wells, to produce a State-specific Federal 

lands to total well ratio. This ratio was then used to approximate State Federal lands wells counts from available annual 

State well totals.

A time series of producing natural gas wells by State 

for 2005–14 was available from the U.S. Energy Information 

Administration (2016c). A similar time series of oil wells by 

State was not available for the study period, so various sources 

were compiled. Oil well counts for 2005–8 were from the U.S. 

Energy Information Administration (2009). Oil well counts 

for 2009–10 and 2013–14 came from World Oil (World Oil, 

2011, 2014; Abraham, 2015; Jordan, 2016). State data were 

not readily available for 2011 and 2012, so trendlines fit to the 

data were used to estimate missing values. However, as of the 

time of publication of this study, State oil well data are now 

available through the EIA’s “U.S. Oil and Natural Gas Wells 

by Production Rate” report (U.S. Energy Information Administration, 2017).

Table 1–1. Inputs and sources for the stationary combustion greenhouse gas emissions estimate.

Input Source

Coal, crude oil, and natural gas production volumes 

from Federal lands

Office of Natural Resources Revenue, data obtained via 

Memorandum of Agreement MOA16–5285

Coal: export data U.S. Energy Information Administration, 2016a

Coal: sector use proportions U.S. Energy Information Administration, 2016a

Coal: sector-specific emission factors U.S. Environmental Protection Agency, 2014

Natural gas: export data U.S. Energy Information Administration, 2016b, table 4.1

Natural gas: sector use proportions U.S. Energy Information Administration, 2013

Natural gas: emission factors U.S. Environmental Protection Agency, 2014

Natural gas: nonenergy storage factor U.S. Environmental Protection Agency, 2016a, table A–62

Petroleum products: refining data U.S. Energy Information Administration, 2015b 

Petroleum products: export data U.S. Energy Information Administration, 2015a

Petroleum products: sector use proportions U.S. Energy Information Administration, 2016b, tables 3.5 and 3.7

Petroleum products: sector-specific emission factors U.S. Environmental Protection Agency, 2014

Table 1–2. Inputs and sources for the mobile sector combustion greenhouse gas emissions estimate.

Input Source

Crude oil production volumes from Federal lands Office of Natural Resources Revenue, data obtained via 

Memorandum of Agreement MOA16–5285

Petroleum products: refining data U.S. Energy Information Administration, 2015b

Petroleum products: export data U.S. Energy Information Administration, 2015a

Petroleum products: sector use proportions U.S. Energy Information Administration, 2016b, tables 3.5 and 3.7

Annual mobile fuel consumption U.S. Environmental Protection Agency, 2016a, table A–92

Annual carbon dioxide mobile emissions U.S. Environmental Protection Agency, 2016b, table 3–12 

Annual methane mobile emissions U.S. Environmental Protection Agency, 2016b, table 3–13 

Annual nitrous oxide mobile emissions U.S. Environmental Protection Agency, 2016b, table 3–14
26 Federal Lands Greenhouse Gas Emissions and Carbon Sequestration in the United States: Estimates for 2005–14

To quantify the variation between the data used for this 

study and the newly available and complete time series data 

from the EIA, consider the comparison of Wyoming well 

counts from both datasets. Oil well counts from this study and 

the new data are nearly identical for the period 2005–8. Variation from 2010 to 2014 was evident: the study dataset oil well 

counts are on average 14 percent lower than the EIA dataset. 

Conversely, gas well counts from this study and the new data 

are nearly identical from 2010 to 2014. Study dataset gas well 

counts are on average 15 percent lower than the new dataset 

from 2005 to 2008. These variations are due to differing gasoil ratios used to define well type, methods of accepting data 

from States, and State reporting schedules.

To review, all well counts in the new EIA dataset are 

higher or unchanged compared to those used in this study. If 

the new dataset had been available during the analysis phase, 

its use would have resulted in a lower ratio of State Federal 

lands wells to total State wells, therefore reducing the onshore 

emissions for petroleum and natural gas systems attributed 

to activities on Federal lands. Using this new dataset would 

be a methodological improvement; however, in terms of 

significance, note that the EPA’s uncertainty on the emissions 

estimate is −25 to 45 percent and that the methods for estimating emissions are an area of rapidly evolving science.

Total offshore oil and gas platform counts were obtained 

from the EPA (U.S. Environmental Protection Agency, 

2017a, b). The total platform counts were split into offshore 

Pacific and offshore Gulf counts by subtracting the estimated 

number of Pacific platforms (a relatively small number) from 

the EPA’s totals. The 2011 Pacific drilling platform counts are 

from Bureau of Ocean Energy Management (Bureau of Ocean 

Energy Management, 2011) available on the National Oceanic and Atmospheric Administration-hosted Marine Cadastre 

website. These platform counts were used for all years in the 

estimate (2005–14) because historical data were not available. 

The depths and types (oil versus gas) of the offshore Pacific 

platforms were determined by using National Oceanic and 

Atmospheric Administration spatial bathymetry data (National 

Oceanic and Atmospheric Administration, 2013) and proprietary USGS oil and gas databases.

This report follows guidance from the EPA (U.S. Environmental Protection Agency, 2015) on emission factors for offshore platforms. Those factors originate from the Gulf Offshore 

Activity Data System and are based on emissions reported for 

2011 (Wilson and others, 2014). For further information on 

the choice of emission factors, consult the EPA guidance (U.S. 

Environmental Protection Agency, 2015). Estimates of emissions from offshore platforms vary over the years included in 

this estimate (2005–14) because reporting initiatives, emissions research, and on-site improvements continue to develop. 

Newer estimates of emissions from offshore production are 

available from the Gulf Offshore Activity Data System (Wilson 

and others, 2017). The emission factors used here are specific 

to both the water depth—deep, depths greater than 656 feet 

(200 meters); shallow, depths less than 656 feet (200 meters)—

and the main hydrocarbon produced (oil or gas). The number 

of platforms in each depth and product category was multiplied 

by the emission factors to generate the estimate. See table 1–3 

for the inputs and sources mentioned in this section.

Active Coal Mine Emissions

Emissions of CH4 from active underground coal mines 

were calculated as the sum of four kinds of emissions: ventilation, degasification, recovered/used, and postmining. Emissions of CH4

 from ventilation and degasification, as well as 

amounts of CH4 recovered, are measured directly by the Mine 

Safety and Health Administration or reported by mine operators (the larger value was used when both measures were 

available). For underground mines, postmining CH4 emissions 

are the product of annual production, the basin-specific in situ 

coal CH4 content, and a fixed postmining emission factor of 

0.325 (U.S. Environmental Protection Agency, 2016a).

Active surface mine emissions of CH4 are the product of 

annual production, basin-specific in situ coal CH4 content, and 

a fixed surface mining emission factor of 1.5 (U.S. Environmental Protection Agency, 2016a). The method for estimating 

postmining emissions for active surface mines is the same 

as that described above for post-mining emissions for active 

underground mines. See table 1–4 for the inputs and sources 

mentioned in this section.

Abandoned Coal Mine Emissions

The CH4 emissions from abandoned underground coal 

mines were calculated with an emissions decline curve that 

used the active emissions on the day of abandonment as the 

starting point. The variables that control the type of decline 

curve are specific to the method of abandonment (sealing, 

venting, or flooding). Emissions from mines with an unknown 

abandonment method were determined by calculating the 

emissions for all three methods of abandonment and then 

using a weighted average of the outputs based on regionspecific abandonment-method statistics. The EPA’s methodology (Franklin and others, 2004; U.S. Environmental Protection 

Agency, 2004) for abandoned mines was the general method 

applied. However, unlike the EPA’s probabilistic approach, 

this USGS estimate is deterministic and was obtained by using 

single region-specific median inputs in the decline curve calculations rather than a range of potential values. This simplification does not significantly affect the results and is in line 

with the simplified approach used in the USGS estimate. See 

table 1–5 for the inputs and sources mentioned in this section.

Exported Fuels Emissions

Emissions associated with exported fuels were estimated 

using the same methods as the domestic stationary and mobile 

combustion calculations. See those sections of this appendix 

for details. The portion of the fuel produced from Federal 

lands that was used in this calculation was based on export 

information from the EIA (table 1–6).
Appendix 1 27

Table 1–3. Inputs and sources for the petroleum and natural gas systems greenhouse gas emissions estimate.

[CO2, carbon dioxide; CH4, methane]

Input Source

CO2 and CH4 natural gas systems emissions U.S. Environmental Protection Agency, 2016b, tables 3–46 and 3–49

CO2 and CH4 petroleum systems emissions U.S. Environmental Protection Agency, 2016b, tables 3–38 and 3–36

National Producing oil and gas well counts U.S. Environmental Protection Agency, 2017a, b

State Producing oil well counts U.S. Energy Information Administration, 2009; World Oil, 2011, 2014; 

Abraham, 2015; Jordan, 2016

State Producing gas well counts U.S. Energy Information Administration, 2016c, table 5

State Federal lands producing oil and gas well counts Bureau of Land Management, written commun., 2016

Offshore platform emission factors U.S. Environmental Protection Agency, 2015, table 1

Total offshore platform counts U.S. Environmental Protection Agency, 2017a, b

Pacific offshore platform counts Bureau of Ocean Energy Management, 2011

Table 1–4. Inputs and sources for the active coal mining greenhouse gas emissions estimate.

[CH4, methane]

Input Source

Production, fuel type, and basin information Office of Natural Resources Revenue, data obtained via 

Memorandum of Agreement MOA16–5285

Basin-specific in situ coal CH4 content U.S. Environmental Protection Agency, 2016a, table A–123

Annual ventilation CH4 volumes U.S. Environmental Protection Agency, Inventory of U.S. Greenhouse Gas 

Emissions and Sinks project team, written commun., 2016 (data reported 

by the Mine Safety and Health Administration)

Annual degasification CH4 volumes U.S. Environmental Protection Agency, Inventory of U.S. Greenhouse Gas 

Emissions and Sinks project team, written commun., 2016 (data reported 

by the Mine Safety and Health Administration

Annual recovered/used CH4 volumes U.S. Environmental Protection Agency, Inventory of U.S. Greenhouse Gas 

Emissions and Sinks project team, written commun., 2016 (data reported 

by the Mine Safety and Health Administration)

Postmining emission factors U.S. Environmental Protection Agency, 2016a, table A–123

Table 1–5. Inputs and sources for the abandoned coal mine greenhouse gas emissions estimate.

Input Source

Abandoned Federal lease mines U.S. Environmental Protection Agency, Inventory of U.S. Greenhouse Gas 

Emissions and Sinks project team, written commun., 2016; John Hovanec, 

Office of Natural Resources Revenue, written commun., 2016

Date of abandonment U.S. Environmental Protection Agency, Inventory of U.S. Greenhouse Gas 

Emissions and Sinks project team, written commun., 2016 (data reported 

by the Mine Safety and Health Administration)

Average emissions at abandonment U.S. Environmental Protection Agency, Inventory of U.S. Greenhouse Gas 

Emissions and Sinks project team, written commun., 2016 (data reported 

by the Mine Safety and Health Administration)

Abandonment method U.S. Environmental Protection Agency, Inventory of U.S. Greenhouse Gas 

Emissions and Sinks project team, written commun., 2016 (data reported 

by the Mine Safety and Health Administration)

Decline curve values Franklin and others 2004; U.S. Environmental Protection Agency, 2004

Abandonment method by basin Franklin and others, 2004; U.S. Environmental Protection Agency, 2004
28 Federal Lands Greenhouse Gas Emissions and Carbon Sequestration in the United States: Estimates for 2005–14

Table 1–6. Inputs and sources for the exported fuels greenhouse gas emissions estimate.

Input Source

Coal export data U.S. Energy Information Administration, 2016a

Natural gas export data U.S. Energy Information Administration, 2016b

Petroleum products export data U.S. Energy Information Administration, 2015a

References Cited

Abraham, K., 2015, Active U.S. oil wells pass the 600,000 

mark: World Oil, v. 236, no. 2, 1 p., accessed August 

14, 2018, at https://www.worldoil.com/magazine/2015/

february-2015/special-focus/active-us-oil-wells-pass-the600-000-mark.

Bureau of Ocean Energy Management, 2011, BOEM Pacific 

active oil and gas platforms: Bureau of Ocean Energy 

Management vector digital data, accessed March 21, 2017, 

at https://www.boem.gov/PC-plat.zip.

Franklin, P., Scheehle, E., Collings, R.C., Coté, M.M., and 

Pilcher, R.C., 2004, Proposed methodology for estimating 

emission inventories from abandoned coal mines—Prepared 

for the 2006 IPCC [Intergovernmental Panel on Climate 

Change] National Greenhouse Gas Inventories Guidelines, 

Fourth Authors/Experts Meeting, Energy—Methane Emissions for Coal Mining and Handling, Arusha, Tanzania, 

[Sept. 28–30, 2004]: U.S. Environmental Protection Agency 

white paper, variously paged, accessed May 2, 2017, 

at https://www.epa.gov/sites/production/files/2016-03/

documents/methodology_abandoned_coalmines.pdf.

Jordan, R., 2016, Producing oil wells tick down as price 

begins to hit: World Oil Magazine, v. 237, no. 2, 1 p., 

accessed February 9, 2017, at https://www.worldoil.com/

magazine/2016/february-2016/special-focus/producing-oilwells-tick-down-as-price-begins-to-hit.

National Oceanic and Atmospheric Administration, 2013, 

Bathymetric contours: National Oceanic and Atmospheric 

Administration vector digital data, accessed June 25, 

2017, at http://www.marinecadastre.gov/data/default.aspx. 

[Dataset moved by time of publication; accessed September 12, 2018, at https://inport.nmfs.noaa.gov/inport/

item/48852.]

U.S. Energy Information Administration, 2009, United States 

total distribution of wells by production rate bracket—

United States total 2009: U.S. Energy Information 

Administration dataset, accessed January 3, 2017, at 

http://www.eia.gov/pub/oil_gas/petrosystem/us_table.html.

U.S. Energy Information Administration, 2013, Table 2.1, 

nonfuel (feedstock) use of combustible energy, 2010, in

Manufacturing energy consumption survey (MECS)—2010 

MECS survey data: U.S. Energy Information Administration, 8 p., accessed May 20, 2016, at https://www.eia.gov/

consumption/manufacturing/data/2010/, under “Energy 

Used as a Nonfuel (Feedstock)” tab.

U.S. Energy Information Administration, 2015a, Table 1, 

U.S. supply, disposition, and ending stocks of crude oil and 

petroleum products, 2014, in Petroleum supply annual, v. 1: 

U.S. Energy Information Administration, 1 p., accessed 

April 12, 2017, at https://www.eia.gov/petroleum/supply/

annual/volume1/archive/2014/psa_volume1_2014.cfm.

U.S. Energy Information Administration, 2015b, Table 23, 

percent yield of petroleum products by PAD and refining districts, 2014, in Petroleum supply annual, v. 1: U.S. 

Energy Information Administration, 1 p., accessed April 

12, 2017, at https://www.eia.gov/petroleum/supply/annual/

volume1/archive/2014/psa_volume1_2014.cfm.

U.S. Energy Information Administration, 2016a, Annual coal 

distribution report 2014, by coal origin State: U.S. Energy 

Information Administration, 47 p., accessed February 

13, 2017, at http://www.eia.gov/coal/distribution/annual/

archive/2014/o_14state.pdf.

U.S. Energy Information Administration, 2016b, Monthly 

energy review, July 2016: U.S. Energy Information 

Administration, 224 p., accessed September 22, 2016, at 

http://www.eia.gov/totalenergy/data/monthly.

U.S. Energy Information Administration, 2016c, Table 5, 

number of wells producing natural gas by State and the Gulf 

of Mexico, 2011–2015, in Natural gas annual 2015: U.S. 

Energy Information Administration, 1 p., accessed April 13, 

2017, at https://www.eia.gov/naturalgas/annual/.

U.S. Energy Information Administration, 2017, Appendix C—

Full datasheet [—to accompany U.S. Energy Information 

Administration, The distribution of U.S. oil and natural gas 

wells by production rate]: U.S. Energy Information Administration, accessed August 14, 2018, at https://www.eia.gov/

petroleum/wells/.
Appendix 1 29

U.S. Environmental Protection Agency, 2004, Methane emissions from abandoned coal mines in the 

United States—Emissions inventory methodology and 

1990–2002 emissions estimates: U.S. Environmental Protection Agency [report] EPA 430–R–04–001, 

54 p. [Also available at https://nepis.epa.gov/Exe/

ZyPDF.cgi/600004JM.PDF?Dockey=600004JM.PDF.]

U.S. Environmental Protection Agency, 2014, Emission factors for greenhouse gas inventories: Washington, D.C., 

U.S. Environmental Protection Agency, 5 p., accessed 

April 4, 2017, at https://www.epa.gov/sites/production/

files/2015-07/documents/emission-factors_2014.pdf.

U.S. Environmental Protection Agency, 2015, Inventory of 

U.S. greenhouse gas emissions and sinks 1990–2013—

Revision to offshore platform emissions estimate: Washington, D.C., U.S. Environmental Protection Agency, 

3 p., accessed April 5, 2017, at https://www.epa.gov/

sites/production/files/2015-12/documents/revisionoffshoreplatforms-emissions-estimate-4-10-2015.pdf.

U.S. Environmental Protection Agency, 2016a, Annexes to the 

inventory of U.S. GHG emissions and sinks [—to accompany U.S. Environmental Protection Agency, Inventory 

of U.S. greenhouse gas emissions and sinks—1990–2014, 

[report] EPA 430–R–16–002]: U.S. Environmental 

Protection Agency, 494 p., accessed April 5, 2017, 

at https://www.epa.gov/ghgemissions/inventory-usgreenhouse-gas-emissions-and-sinks-1990-2014.

U.S. Environmental Protection Agency, 2016b, Inventory of 

U.S. greenhouse gas emissions and sinks—1990–2014: 

U.S. Environmental Protection Agency, [report] EPA 

430–R–16–002, variously paged, plus additional online 

data tables, accessed April 5, 2017, at https://www.epa.gov/

ghgemissions/inventory-us-greenhouse-gas-emissions-andsinks-1990-2014.

U.S. Environmental Protection Agency, 2017a, Annex 3.5—

Methodology for estimating CH4 and CO2 emissions from 

petroleum systems, in Natural gas and petroleum systems 

in the GHG inventory—Additional information on the 

1990–2015 GHG inventory (published April 2017) [—to 

accompany U.S. Environmental Protection Agency, Inventory of U.S. greenhouse gas emissions and sinks—1990–

2015, report EPA 430–P–17–001]: U.S. Environmental 

Protection Agency, 7 tables, accessed February 14, 2018, 

at https://www.epa.gov/ghgemissions/natural-gas-andpetroleum-systems-ghg-inventory-additional-information1990-2015-ghg.

U.S. Environmental Protection Agency, 2017b, Annex 3.6—

Methodology for estimating CH4 and CO2 emissions from 

natural gas systems, in Natural gas and petroleum systems 

in the GHG inventory—Additional information on the 

1990–2015 GHG inventory (published April 2017) [—to 

accompany U.S. Environmental Protection Agency, Inventory of U.S. greenhouse gas emissions and sinks—1990–

2015, [report] EPA 430–P–17–001]: U.S. Environmental 

Protection Agency, 11 tables, accessed February 14, 2018, 

at https://www.epa.gov/ghgemissions/natural-gas-andpetroleum-systems-ghg-inventory-additional-information1990-2015-ghg.

Wilson, D., Billings, R., Chang, R., Enoch, S., Do, B., Perez, 

H., and Sellers, J., 2017, Year 2014 gulfwide emissions 

inventory study: Bureau of Ocean Energy Management, 

OCS study BOEM 2017–044, prepared by Eastern Research 

Group, Inc. of Morrisville, N.C., 134 p., accessed March 7, 

2018, at https://www.boem.gov/2014-Gulfwide-EmissionInventory/.

Wilson, D., Billings, R., Chang, R., Perez, H., and Sellers, 

J., 2014, Year 2011 gulfwide emissions inventory study: 

Bureau of Ocean Energy Management, OCS study BOEM 

2014–666, prepared by Eastern Research Group, Inc. 

of Morrisville, N.C., 180 p., accessed March 7, 2018, at 

https://www.boem.gov/2011-Gulfwide-Emission-Inventory/.

World Oil, 2011, US oil wells see slight increase in 2010: 

World Oil, v. 232, no. 2, 1 p., accessed February 9, 2017, at 

https://www.worldoil.com/magazine/2011/february-2011/

special-focus/us-oil-wells-see-slight-increase-in-2010.

World Oil, 2014, Well count for active U.S. oil wells nears 

600,000: World Oil, v. 235, no. 2, 1 p., accessed August 

14, 2018, at https://www.worldoil.com/magazine/2014/

february-2014/special-focus/well-count-for-active-us-oilwells-nears-600-000.
30 Federal Lands Greenhouse Gas Emissions and Carbon Sequestration in the United States: Estimates for 2005–14

Appendix 2. Detailed Methods: Terrestrial Ecosystems-Associated Carbon 

Emissions and Sequestration on Federal Lands

Introduction

For this U.S. Geological Survey study, we used a 

dynamic global vegetation model to estimate net primary 

productivity (NPP), net ecosystem productivity, and net biome 

productivity for all Federal land areas in the conterminous 

United States. Within these areas, we estimated the changes in 

carbon stocks and fluxes for forests, grasslands, shrublands, 

wetlands, and agricultural lands resulting from processes associated with deforestation, afforestation, reforestation, agricultural contraction and expansion, urbanization, forest harvest, 

and wildfire. Historical changes in land use and land cover 

(LULC) were estimated from a range of remote sensing-based 

datasets. Carbon dynamics within the dynamic global vegetation model were calibrated on the basis of forest and agricultural inventory data from the U.S. Department of Agriculture 

(USDA) and remote sensing estimates of NPP.

Integrated Biosphere Simulator Dynamic Global 

Vegetation Model

For this study, the following LULC changes were 

considered: logging, deforestation (forest to agriculture 

conversion), afforestation (agriculture to forest conversion), 

agriculture contraction (agriculture to grassland conversion), 

agriculture expansion (grassland to agriculture conversion), 

and urbanization (forest to urban, grassland to urban, and 

agriculture to urban conversion). The Integrated Biosphere 

Simulator (IBIS) models fractional vegetation cover within 

a single land pixel, which enables the model to run at coarse 

resolution (1 kilometer [km]) derived from high-resolution 

LULC products (for example, 30 meters [m]) (Liu and Sleeter, 

2018). Most of the land pixels are a mixture of several landcover types. The IBIS model tracks the percent area of each 

land-cover type within each land pixel. When an LULC or 

disturbance event (for example, reforestation, deforestation, or 

urbanization) occurs, cover fractions are transferred between 

the relevant land-cover types.

In addition to disturbances detectable through remote 

sensing methods, less detectable events like forest thinning activities were also considered. The forest thinning 

rate was calculated using recent annualized forest inventory 

data (Zhou and others, 2013). Thinning activity was loosely 

defined as the cutting-related vegetation carbon loss of less 

than 50 percent during two consecutive observation periods 

(around 5 years) in order to make the overall thinned-area 

percentage (that is, 61 percent of the total forest cutting area) 

in agreement with earlier estimates (Masek and others, 2011; 

Oswalt and Smith, 2014).

Model calibrations were performed by comparing 

ecoregion-level NPP, live vegetation, dead vegetation, and 

crop yield with observations. Observations included remote 

sensing-derived, 1-km-resolution Moderate Resolution Imaging Spectrometer NPP products for 2001–5 (Zhao and others, 

2005), Forest Inventory and Analysis program-derived forest 

live and dead vegetation growth curves obtained from the 

Carbon OnLine Estimator (Van Deusen and Heath, 2015), and 

county-level agricultural data (U.S. Department of Agriculture, 2011). During calibration, NPP and grain-yield scalars 

were generated on the basis of differences between IBIS outputs and observations. The scalars were then used to modify 

the maximum Rubisco-limited rate of carboxylation (Vmax) 

of related plant functional types (forest or crop) in a new IBIS 

run. For the forest live and dead vegetation calibration, 100 

years of growth of live and dead vegetation from IBIS simulation were compared with the Carbon OnLine Estimator data. 

Scalars were generated to modify the tree mortality rate and 

the transfer rate of deadwood to ground litter.

Data Sources

Input data related to land cover include (1) 30-m 

vegetation-cover type and vegetation-height information 

from the USDA–U.S. Department of the Interior LANDFIRE 

program (Rollins, 2008), (2) five dates of 60-m resolution 

land-cover-type information from the U.S. Geological 

Survey (USGS) Land Cover Trends project (Loveland and 

others, 2002; Sleeter and others, 2013), (3) 30-m resolution 

annual wildland fire scar and burn severity information 

from the USGS–USDA Monitoring Trends in Burn Severity project (Eidenshink and others, 2007), and (4) freshwater 

and saline water wetland-fraction map derived from 30-m 

USGS National Land Cover Database and National Oceanic 

and Atmospheric Administration Coastal Change Analysis 

Program data (Homer and others, 2007). All land-cover maps 

were aggregated to a consistent 960-m resolution in this 

study. In addition, regional rates of forest stand thinning were 

derived from previous studies (Law and others, 2012; Zhou 

and others, 2013). We used Parameter-elevation Regression on 

Independent Slopes Model 4-km resolution monthly precipitation and temperature data from 1971 to 2010 as the main 

climate drivers (Daly and others, 2008). Other climate variables, such as relative humidity and wind speed, were monthly 

normals for 1961–90. The Soil Survey Geographic Database 

(Natural Resources Conservation Service, 2009) soil carbon 

content was used to initialize soil condition. For the period 

2011–15, no changes in LULC were modeled owing to a lack 

of spatially explicit data. However, fire and climate data were 

available and were used in the model simulations.
Appendix 2 31

References Cited

Daly, C., Halbleib, M., Smith, J.I., Gibson, W.P., Doggett, 

M.K., Taylor, G.H., Curtis, J., and Pasteris, P.P., 2008, 

Physiographically sensitive mapping of climatological 

temperature and precipitation across the conterminous 

United States: International Journal of Climatology, 

v. 28, no. 15, p. 2031–2064. [Also available at 

https://doi.org/10.1002/joc.1688.]

Eidenshink, J., Schwind, B., Brewer, K., Zhu, Z.-L., Quayle, 

B., and Howard, S., 2007, A project for monitoring trends in 

burn severity: Fire Ecology, v. 3, no. 1, p. 3–21. [Also available at https://doi.org/10.4996/fireecology.0301003.]

Homer, C.G., Deqitz, J., Fry, J., Coan, M., Hossain, N., 

Larson, C., Herold, N., McKerrow, A., VanDriel, J.N., and 

Wickham, J., 2007, Completion of the 2001 National Land 

Cover Database for the conterminous United States: Photogrammetric Engineering & Remote Sensing, v. 73, no. 4, 

p. 337–341.

Law, B.E., Hudiburg, T.W., and Luyssaert, S., 2012, Thinning 

effects on forest productivity—Consequences of preserving 

old forests and mitigating impacts of fire and drought: Plant 

Ecology & Diversity, v. 6, no 1., p. 73–85. [Also available 

at https://doi.org/10.1080/17550874.2012.679013.]

Liu, J., and Sleeter, B.M., 2018, Simulated 1km resolution 

1971-2015 ecosystem carbon variables from the IBIS model 

(2017/09/12): U.S. Geological Survey data release, accessed 

October 2, 2018, at https://doi.org/10.5066/P9CQPG86.

Loveland, T.R., Sohl, T.L., Stehman, S.V., Gallant, A.L., 

Sayler, K.L., and Napton, D.E., 2002, A strategy for estimating the rates of recent United States land-cover changes: 

Photogrammetric Engineering & Remote Sensing, v. 68, 

no. 10, p. 1091–1099.

Masek, J.G., Cohen, W.B., Leckie, D., Wulder, M.A., 

Vargas, R., de Jong, B., Healey, S., Law, B., Birdsey, R., 

Houghton, R.A., Mildrexler, D., Goward, S., and Smith, 

W.B., 2011, Recent rates of forest harvest and conversion in North America: Journal of Geophysical Research, 

v. 116, no. G4, 22 p. [Also available at https://doi.

org/10.1029/2010JG001471.]

Natural Resources Conservation Service, 2009, Soil Survey 

Geographic (SSURGO) Database: Natural Resources Conservation Service database, accessed November 20, 2015, at 

https://gdg.sc.egov.usda.gov/.

Oswalt, S.N., and Smith, W.B., eds., 2014, U.S. forest resource 

facts and historical trends: U.S. Forest Service [report] 

FS-1035, 62 p. [Also available at https://www.fia.fs.fed.

us/library/brochures/docs/2012/ForestFacts_1952-2012_

Metric.pdf.]

Rollins, M.G., 2008, LANDFIRE—A nationally consistent 

vegetation, wildland fire, and fuel assessment: International 

Journal of Wildland Fire, v. 18, no. 3, p. 235–249, accessed 

October 1, 2010, at https://doi.org/10.1071/WF08088.]

Sleeter, B.M., Sohl, T.L., Loveland, T.R., Auch, R.F., 

Acevedo, W., Drummond, M.A., Sayler, K.L., and 

Stehman, S.V., 2013, Land-cover change in the conterminous United States from 1973 to 2000: Global Environmental Change, v. 23, no. 4, p. 733–748. [Also available at 

https://doi.org/10.1016/j.gloenvcha.2013.03.006.]

U.S. Department of Agriculture, 2011, QuickStats, U.S. 

Department of Agriculture web page, accessed August 2011, 

at https://quickstats.nass.usda.gov/.

Van Deusen, P., and Heath, L.S., 2015, COLE web applications suite, version 2.0: National Council for Air and Stream 

Improvement and U.S. Forest Service, accessed November 

23, 2015, at http://www.ncasi2.org/COLE/.

Zhao, M., Heinsch, F.A., Nemani, R.R., and Running, S.W., 

2005, Improvements of the MODIS terrestrial gross and 

net primary production global data set: Remote Sensing of 

Environment, v. 95, no. 2, p. 164–176. [Also available at 

https://doi.org/10.1016/j.rse.2004.12.011.]

Zhou, D., Liu, S., Oeding, J., and Zhao, S., 2013, Forest cutting and impacts on carbon in the eastern 

United States: Scientific Reports, v. 3, 7 p. [Also available 

at https://doi.org/10.1038/srep03547.]

For more information about this publication, contact

Director, Eastern Energy Resources Science Center

U.S. Geological Survey

956 National Center

12201 Sunrise Valley Drive

Reston, VA 20192

For additional information visit https://energy.usgs.gov/GeneralInfo/

ScienceCenters/Eastern.aspx

Publishing support provided by the Reston Publishing Service Center
Merrill and others—Federal Lands Greenhouse Gas Emissions and Sequestration in the United States: Estimates for 2005–14—Scientific Investigations Report 2018–5131

ISSN 2328-0328 (online)

https://doi.org/10.3133/sir20185131