RCP4.5 Update

Allison Thomson and the GCAM model group
Joint Global Change Research InstitutePacific Northwest National Laboratory
September 15, 2009
IAMC Annual Meeting

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GCAM (formerly MiniCAM) Structure2

Initial basis for RCP4.5
US Climate Change Science Program scenarios
published in 2007.
Population peaks at 9 billion in 2065 and declines to8.7 billion in 2100
Global GDP grows by an order of magnitude by 2100
Energy consumption triples by 2100
Carbon price of $500 per ton C by 2100
Net negative emissions from electric power generation
Renewables, nuclear and CCS all deployedMechanism for valuing terrestrial carbon included
Reference: Clarke, L, J Edmonds, H Jacoby, H Pitcher, J Reilly, R Richels. 2007. Scenarios of Greenhouse Gas
Emissions and Atmospheric Concentrations. Sub-report 2.1A of Synthesis and Assessment Product 2.1 by the U.S.
Climate Change Science Program and the Subcommittee on Global Change Research. Department of Energy,
Office of Biological & Environmental Research, Washington, 7 DC., USA, 154 pp.
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Modifications for the RCP4.5
Scenario drivers and core model assumptions
remain the same
RCP4.5 was run with an updated version ofGCAM:Agriculture, Land Use and NonCO2 greenhouse gas components
updated and fully integrated in ObjECTS GCAM
Updated base year land use and emissions inventories toharmonized RCP data
Modified mechanism for valuing terrestrial carbon equally to fossil
fuel and industrial carbon
Updated version of MAGICC to be consistent with other RCP
modeling groups.
4Results
750

CO2 concentration

GCAM RCP 4.5
GCAM RCP reference

600

450

300

1200

geothermal

150

0
2000

2020

2040

2060

2080

Primary Energy
Consumption

1000

solarwind800

hydronuclear

2100

EJ/yr

Atmospheric CO2 Concentration (ppm)

900bio w/ccs

600

bio
coal w/ccs

400

coalgas w/ccs

200

gasoil w/ccs
oil0
2005
52020

2035

2050

2065

2080

2095

Total Cropland
1600
1400
Western Europe

1200

USA
Southeast Asia

millions of ha1000

Middle East
Latin America

800

Korea
Japan600

India
Former Soviet Union

400

Eastern Europe
China

200

CanadaAustralia_NZ

02000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100

Downscaled
forharmonization

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Terrestrial carbon valuation•Reduce LUC emissions byexpansion and preservation offorests•Decline in cropland area

AfricaLand UseBeef production
Feed for beef shifts into dedicated crops
CH4 Emissions from Agriculture

80

18070

16060

14050120
TgCH4/yrbeef production

904030

80
60

2040

1001990

100202005

2020

2035

Food Crops

2050

2065

Fodder Crops

Pasture

2080

2095

02000

2010

2020

2030

2040

2050

2060

Overall production declines, causing declining emissions
72070

2080

2090

2100

Updates since the data release in May
Model name – from MiniCAM to GCAM
Updates and corrections to emissions
BC/OC inventory update and re-release in July
Additional correction to shipping grids in September

Climate model implementation – land use
Initial interpretation of land use by CM groups revealed somelarger questions about the harmonization and hand-off steps.

Land use downscaling algorithms updated and newproducts due to be released in a few weeks.
Extension to 2300 – remain stabilized at 4.5.

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Future research directions
Continue working with UNH and refining LU downscaling
algorithms for GCAM to be consistent with scenario
assumptions
Implications for harmonization algorithms?

Comparison of non-CO2 GHG emissions across RCP
modelsDevelopment of storylines and communication with users
in CM and IAV communities
UNH and CM groups meeting this week

Continued improvements to the model9