Human Activities, CO2 Emissions and Concentrations, and Climate Change

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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

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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

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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?

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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
• gt35 PgC/y (SRES A1C AIM)
• Cumulative emissions 1990 to 2100 range from
• lt775 Pg to (SRES B1T MESSAGE)
• gt2,500 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.

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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 0.6-2.6 PgC/y)
• Deforestation
• Soil cultivation

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Fossil Fuel Carbon Emissions1999
Source Carbon Dioxide Information Analysis
Center, Oak Ridge National Laboratory.
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Land-use Carbon Emissions1999
Range of Land-use Emissions
Source Carbon Dioxide Information Analysis
Center, Oak Ridge National Laboratory, based on
Houghton.
Source IPCC WG1 Third Assessment Report.
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Global Primary Energy
Source IIASA
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Historical Fossil Fuel CO2 Emissions 1751 to 1999
Source Carbon Dioxide Information Analysis
Center.
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Land-use Emissions 1850 to 2000
Source Carbon Dioxide Information Analysis
Center, Oak Ridge National Laboratory, based on
Houghton.
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ENERGY RESOURCESWill the Problem Go Away on Its
Own?

• Wont 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?

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Atmosphere 790 PgC
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Scenarios of Future Emissions

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

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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)

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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)
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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.

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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
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Increased Life ExpectancyExacerbates Aging and
Increases Population
Both use TCF1.9
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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.

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Growth in labor productivity
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Stabilizing CO2Base 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
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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
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Range 765 to 2,531 PgC
Median 1,500 PgC
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Uncertainty in Stabilization Trajectories
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Cumulative Emissions and Stabilization
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Cumulative Emissions and Stabilization
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Technology Alone Wont 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.
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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.

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IPCC SRES Reference Case Land-Use Change
Emissions Scenarios
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Land-Use Emissions are Sensitive to Agricultural
Productivity Growth Rates and to Energy Policy
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CO2 Concentrations
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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)

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Range of Global Mean Surface Temperatures 2000
to 2100
Source IPCC WG1 Third Assessment Report.
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Uncertainty AnalysisScott, et al. (2000)
Distribution of Temperature Increase Base Case
Number of observations
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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
• gt35 PgC/y (SRES A1C AIM)
• Cumulative emissions 1990 to 2100 range from
• lt775 Pg to (SRES B1T MESSAGE)
• gt2,500 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.