Science Based Policy for
Addressing Energy and
Environmental Problems
Robert Sawyer
Class of 1935 Professor of Energy Emeritus
University of California at Berkeley
32nd International Symposium on Combustion
McGill University, Montreal
6 August 2008
Science for Policy Decisions—
Three Key Areas
• Air Pollution
• Global Warming
• Fuel Resources
GLOBAL WARMING
Global Average Radiative Forcing
IPCC Fourth Assessment, 2007
Keeling Curve, CO2 at Mauna Loa
Red line is 57% of fossil fuel CO2 emissions
Paleoclimate CO2 and
Temperature from Ice Core Data
Four Global Warming Questions
• 1) Is global warming occurring ? (science)
• 2) What is the cause? (science)
• 3) What are the likely consequences?
(science based prediction)
• 4) What should we do about it? (policy)
Global Warming is Occurring
• Historical records of land and sea
temperatures
• Satellite measurements
Global Warming is Occurring
Mean Land and Ocean Temperatures
Annual Mean Global Temperature
Greenhouse Gas Warming is
Moderated by Negative Forcings
We Are the Cause of
Global Warming
• Anthropogenic contributions dominate
radiative forcings that control earth’s
temperature
• IPCC Fourth Assessment: “There is a
very high confidence that the global
average new effect of human activities
since 1750 has been one of warming,
with a radiative forcing of +1.6 [+0.6 to
+2.4] W/m2”
The Consequences of Global
Warming are Uncertain
• Some effects are already observable
– Arctic ice is shrinking more rapidly than
predicted
– Tundra melting, increased Greenland ice cap
summer melt, breakup of West Antarctic shelf
• Model based projections match historical
temperature data
2007 Minimum Sea Ice Extent
September 1979-1983 Average
September 2002-2006 Average
Universität Bremen
Sea Level Rise Impact
Implications for Combustion
Global Warming
• Improve efficiency of combustion and enduse devices (efficiency, efficiency,
efficiency)
• Carbon capture and sequestration
presents challenges and opportunities
• Control of more frequent large forest fires
• Lower carbon alternatives to petroleum
FUEL RESOURCES
Fossil Fuel Resources far
Exceed 1750–2004 Consumption
1400
1200
? **
IPCC
Proven reserves*
Gt C
1000
800
600
Methane
Hydrates
Emissions (CDIAC)
*Oil & gas from EIA
600
500
400
EIA
** Unconventional oil & gas;
uncertain, could be large
300
200
400
Shale
Oil
200
Tar
Sands
0
Oil
Gas
Coal
Other
Source: Hansen 2006, www.columbia.edu/~jeh1/agu_communicating.pdf
100
0
CO2 (ppmv)
Reserve growth
Production Costs and Supplies
of Liquid Transportation Fuels
Farrell and Brandt
Greenhouse Gas Emissions,
New Passenger Cars
Fossil Fuel Use Trends
note different
scales
Implications for Combustion
Fuel Resources
• Lower carbon alternatives to petroleum
• Electricity begins to displace combustion
fuels in surface transportation
• Hydrogen a long term (mid-century)
option
• Prepare for a phase down of carbon fuels
Beijing
AIR POLLUTION
Los Angeles
Guatemala
Air Pollutants
•
•
•
•
•
•
•
CO
SO2
NO2
O3
Pb
Particulates
Air contaminants/air toxics
Adverse Health Effects Evidence
• Human clinical exposures
• Animal studies
• Epidemiology
– Large samples (statistical strength)
– Relevant, real-world exposures
– Uncertain exposures
• Shift from pulmonary to cardiovascular
effects
Air Quality Goals
Particulate Matter
•
•
•
•
•
TSP: total suspended particulate
PM10
PM2.5
PMx
Nanoparticles
Mortality Relative Risks from
10-µg/m3 Increase in PM2.5
Jarrett, et al.
Implications for Combustion
Air Pollution
• Industrialized countries have reduced
combustion generated pollutant emissions
[gm/MJ] by about 98%
– Total emissions diminished by growth
– Transfer to developing countries
• Urgent public health need to reduce
cooking and heating emissions in agrarian
and developing societies