1. Human Activities, CO2 Emissions and Concentrations, and Climate Change
The Ocean in a High CO2 World
An International Science Symposium
Jae Edmonds, Hugh Pitcher, and Steve Smith
10 May 2004
Joint Global Change Research Institute
Paris, France

2. Organizers of the meeting US DOE Office of Science
Thanks to
Organizers of the meeting
US DOE Office of Science
EPRI
Other sponsors of the GTSP
Nebojsa Nakicenovic, Brian Fisher, Hugh Pitcher, Charlette Geffen 2

3. Key Question for Today What are the sources of CO2 emissions?
How much carbon is there?
What are the fundamental drivers of CO2 emissions?
What range of CO2 emissions trajectories could be anticipated (reference and stabilization)?
What temperature regimes might be anticipated? 3

4. Final Thoughts
Reference case fossil fuel and land-use change carbon emissions are a major source of uncertainty in CO2 loading of the atmosphere and oceans.
FF emissions range in 2100 from
~3 PgC/y (SRES B1T MESSAGE) to
>35 PgC/y (SRES A1C AIM)
Cumulative emissions 1990 to 2100 range from
<775 Pg to (SRES B1T MESSAGE)
>2,500 Pg (SRES A1C AIM)
The high end of these ranges are truncated in stabilization scenarios.
Emissions uncertainty combined with uncertainty in climate sensitivity implies a wide range of possible future carbon-climate regimes. 4

5. Sources of Anthropogenic CO2 Emissions
Fossil fuel use (6.5 PgC/y in 1999)
Natural gas 13.7 TgC/EJ
Oil 20.2 TgC/EJ
Coal 25.5 TgC/EJ
Industrial process emissions (e.g. cement)
0.2 Pgc/y
Land-use change emissions (1.7; PgC/y)
Deforestation
Soil cultivation 5

6. Fossil Fuel Carbon Emissions 1999
Source: Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory. 6

7. Land-use Carbon Emissions 1999
Range of Land-use Emissions
Source: Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, based on Houghton.
Source: IPCC WG1 Third Assessment Report. 7

8. Global Primary Energy
Source: IIASA 8

9. Historical Fossil Fuel CO2 Emissions 1751 to 1999
Source: Carbon Dioxide Information Analysis Center. 9

10. Land-use Emissions 1850 to 2000
Source: Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, based on Houghton. 10

11. ENERGY RESOURCES Will the Problem Go Away on Its Own?
Won’t the limited conventional oil and gas resource force a transition in the near term to a world based on energy efficiency and renewable and nuclear energy forms? 11

12. Atmosphere 790 PgC 12

13. Scenarios of Future Emissions
Scenarios of future anthropogenic carbon emissions to the atmosphere use complex energy-economy-land-use models. 13

14. Future Carbon Emissions Scenarios
Which of the literally thousands of parameters are most important to determining future emissions of greenhouse gases?
Uncertainty analysis conducted to explore precisely this question.
Edmonds, Reilly, Gardner and Brenkert (1986)
Scott, Sands, Edmonds, Liebetrau and Engel (2000)
Others include Nordhaus and Yohe (1983), Hammitt (1992), Manne and Richels (1993), Alcamo, et al. (1994), Dowlatabadi (1999), Gritsevskyi and Nakicenovic (1999) 14

15. Results From an Uncertainty Analysis
Technology is the broad set of processes covering know-how, experience and equipment, used by humans to produce services and transform resources.
(Not just devices) 15

16. Demographics
Future global population is relatively certain in the near term,
But uncertain in the long term.
Forecasts of population growth have risen, peaked and declined over the past 25 years.
The present best guess population is about where it was in 1978.
Future populations are aging rapidly. 16

17. Population Trajectories Are Falling
Population estimates have declined recently
Many scenarios show global populations declining at the end of the 21st century.
Lutz et al., 1997, 2001 17

18. Increased Life Expectancy Exacerbates Aging and Increases Population
Both use TCF=1.9 18

19. Labor Productivity GDP = Labor productivity * Labor(hours)
Labor productivity growth rates are the major determinant of the scale of economic activity.
They are relatively stable in the developed world.
They are highly varied in the developing world.
Uncertainty in developing country labor productivity growth is a major source of uncertainty in carbon emissions. 19

20. Growth in labor productivity20

21. Stabilizing CO2 Base Case and “Gap” Technologies
Assumed Advances In
Fossil Fuels
Energy intensity
Nuclear
Renewables
Gap technologies
Carbon capture & disposal
Adv. fossil
H2 and Adv. Transportation
Biotechnologies
Soils, Bioenergy, adv. Biological energy
The “Gap” 21

22. Range of Reference Case Fossil Fuel Carbon Emissions
Source: IIASA
Median SRES 2100 emission = 14.4 PgC/y
Open literature 2100 emissions ~20 PgC/y 22

23. Range 765 to 2,531 PgC
Median 1,500 PgC 23

24. Uncertainty in Stabilization Trajectories
Stabilization of CO2 concentrations implies that emissions peak and decline. 24

25. Cumulative Emissions and Stabilization25

26. Cumulative Emissions and Stabilization26

27. Technology Alone Won’t NECESSARILY Stabilize CO2 Concentrations
Energy Related Carbon Emissions
A reference case with advanced technology development of carbon capture and H2, but no climate policy.
A reference case with continued technology development, and no climate policy.
Emissions path that stabilizes CO2 concentrations at 550 ppm. 27

28. Land-use change emissions depend on
Land Use Emissions
Land-use change emissions depend on
Population
Income
Technology
Climate (including water)
Policy (including climate policy)
Land use emissions are uncertain, but
Generally lower than fossil fuel emissions. 28

29. IPCC SRES Reference Case Land-Use Change Emissions Scenarios29

30. Land-Use Emissions are Sensitive to Agricultural Productivity Growth Rates and to Energy Policy
Temperature stabilization scenario
MiniCAM B2 Reference scenario 30

31. CO2 Concentrations 31

32. Climate change is more than CO2
15 Greenhouse Related Gases Tracked by MiniCAM
Carbon Dioxide
Methane
15 Source Sectors
Energy, Human Wastes, Agriculture, Land-Use
Nitrous Oxide
12 Source Sectors
Energy, Human, Industrial, Agriculture, Land-Use
Halocarbons, etc.
15 Source Sectors (7 gases)
Reactive Gases
NOx, VOC, CO
Sulfur Dioxide
Carbonaceous Aerosols
Black Carbon & Organic Carbon
19 Source Sectors each (Energy & Land-Use Combustion) 32

33. Range of Global Mean Surface Temperatures: 2000 to 2100
Source: IPCC WG1 Third Assessment Report. 33

34. Uncertainty Analysis Scott, et al. (2000)
Distribution of Temperature Increase
Base Case
Number of observations 34

35. Final Thoughts
Reference case fossil fuel and land-use change carbon emissions are a major source of uncertainty in CO2 loading of the atmosphere and oceans.
FF emissions range in 2100 from
~3 PgC/y (SRES B1T MESSAGE) to
>35 PgC/y (SRES A1C AIM)
Cumulative emissions 1990 to 2100 range from
<775 Pg to (SRES B1T MESSAGE)
>2,500 Pg (SRES A1C AIM)
The high end of these ranges are truncated in stabilization scenarios.
Emissions uncertainty combined with uncertainty in climate sensitivity implies a wide range of possible future carbon-climate regimes. 35