# Presentation: 801912

## U.S. Climate Change Research Program

**Carbon Cycle**
**Ecosystems**
**Land Use and Land Cover Change**

**William Hohenstein, Department of Agriculture, Moderator**
**Bill Emanuel, University of Virginia**
**Steve Wofsy, Harvard University**
**Richard Houghton, Woods Hole Research Center**
**Daniel Lashof, Natural Resources Defense Council**
**Cynthia Rosenzweig, NASA-Goddard Institute for Space Studies**
**Jeff Amthor, Department of Energy, Rapporteur**
**Allen Solomon, Environmental Protection Agency, Rapporteur**

**Program Element Interactions and Linkages**

## Carbon CycleEcosystemsLand-Use and Land Cover Change

**Linkages between carbon cycle, ecosystem, and land use and land cover change sections of the plan.**
**Comments by invited reviewers.**
**Opportunities for questions, comments, and discussion from workshop participants.**

**Submit comments electronically according to instructions under Strategic Plan on**
**http://www.climatescience.gov/**** **

## U.S. Climate Change Research Program

**Carbon Cycle**
**Ecosystems**
**Land Use and Land Cover Change**

**Program Element Interactions and Linkages**

**Bill Emanuel**
**University of Virginia**

## Future greenhouse gas concentrations?

**What will be the future atmospheric CO****2**** and CH****4**** concentrations?**
**How will terrestrial and marine carbon sources and sinks change in the future?**

**The carbon cycle science program will collaborate with all CCRP research elements to assemble, merge, and analyze carbon, biogeochemical, physical, and socioeconomic information for comprehensive reporting on the state of the global carbon cycle.**

**Broad carbon cycle questions require consideration of land use, land cover, and ecosystems:**

## Carbon cycle research premises:

**Elevated atmospheric CO****2**** concentrations, additions of nutrients, and changes in land management practices can significantly enhance or reduce ecological carbon sinks.**
**Northern Hemisphere terrestrial sink ******** 1.8 ******** 10****15**** gC/year**
**Recovering forests**
**Fire management**
**Increasing CO****2****, N deposition, and climatic change**
**Better understanding and analysis capabilities are prerequisites for planning, implementing, and monitoring North American carbon sequestration.**

**The carbon cycle section of the plan acknowledges an urgent need for improved understanding of the processes of land-use change and the impacts of environmental and resource management decisions.**

## Carbon cycle research questions:

**What are the magnitudes and distributions of North American and of global carbon sources and sinks, how are they changing, and what processes are controlling their dynamics?**
**What are the effects of past, present, and future land-use change and resource management practices on carbon sources and sinks?**
**How will the earth system respond to various options for managing carbon in the environment?**

**Central US extending to continental field campaigns.**
**Biomass and soil carbon inventories.**

**Networks of long-term experimental sites.**
**Remote sensing.**

**Field studies, experiments, modeling.**
**Monitoring.**

## Land use and land cover change research premises:

**The combination of climate and land-use change may have profound effects on the habitability of the planet in more significant ways than either acting alone.**
**While land-use change is often a driver of environmental and climatic changes, a changing climate can in turn affect land use and land cover.**

## Land use and land cover change objectives:

**Investigate the primary drivers of land use and land cover change.**
**Develop 10****–50**** year projections of land use and land cover.**
**U.S.**
**Global**
**Assess impacts on environmental, social, and economic systems and on human health.**

**Initiatives linked to carbon cycling and ecosystems include:**

**Process models of land use and land cover dynamics.**

**Mapping landscape attributes.**
**Integrating remote sensing and *****in situ***** data.**

## Ecosystem carbon cycling objectives:

**Determine linkages and feedbacks between ecosystems and global change.**
**Altered ecosystem exchanges of greenhouse gases, aerosols, and volatile organic compounds.**
**Changes in ecosystem surface albedo.**
**Changes in the fraction of absorbed radiation used to evaporate water compared to direct heating of plants and soils.**

**Large-scale field experiments.**
**Long-term monitoring.**
**Models incorporating remote sensing data.**
**Spatially explicit ecosystem models.**