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1. Climate Change:
Science and Ethical Implications
Bill Riley
Earth Sciences Division
Lawrence Berkeley National Laboratory
Acknowledgements:
IPCC and UCS
2. Discussion Outline
• Global Climate Change
– What is climate change?
– Observations
– Predictions and impacts
• Ethical and Political Issues
3. Intergovernmental Panel on
Climate Change (IPCC)
• Established by the UN and World
Meteorological Organization in 1988
• Assess the scientific, technical, and
socio-economic information relevant for
the understanding of the risks of
human-induced climate change
• Assessments based on published and
peer-reviewed literature
6. The natural greenhouse effect keeps the earth about 60°F warmer than it otherwise
would be. Without the greenhouse effect, life as we know it would not be possible.
Source: OSTP
12. • Clear correlation
between atmospheric
CO2 and temperature
over last 160,000 years
• Current level of CO2 is
outside bounds of
natural variability
•Rate of change of CO2
is also unprecedented
Source: OSTP
13. If nothing is done to slow
2100
greenhouse gas emissions. . .
• CO2 concentrations will likely
be more than 700 ppm by 2100
• Global average temperatures
projected to increase between
2.5 - 10.4°F
14. Main Findings of WG I
• Extensive and wide-spread evidence that the
earth is warming; we are already seeing the first
clear signals of a changing climate.
• Human activities are changing the atmospheric
concentrations of greenhouse gases.
• New and stronger evidence of a human influence
on climate.
15. Numerical Modeling
• In many scientific disciplines, numerical
modeling is the way
– we develop “understanding” of system
behavior
• Particularly useful when experiments are
impossible or difficult to perform, e.g.,
– The Big Bang
– Climate change
– Evolution
16. Numerical Modeling
• Modeling is a synthesis of the physical,
chemical, biological, etc., processes
important in a system’s functioning
– Often enumerated in mathematical
relationships between the various ‘state’
variables of the system
17. General Circulation Model
• Numerical model of
– Atmospheric momentum, energy, and mass transport
– Land surface trace-gas and energy exchange with the
atmosphere
– Oceanic water movement and energy exchange with
the atmosphere
– Designed to run >100 year simulations
• GCMs differ because they represent these
complex interactions in different ways
• The models do a reasonable job simulating our
current climate (e.g., seasonality) and
reproducing known changes from past climates
18. Temperature Projections
• Global average
temperature is
projected to
increase by 2.5
to 10.4°F from
1990 to 2100
• Projected rate of
warming is
unprecedented
for last 10,000
years
Source: IPCC TAR 2001
19. Variations of the Earth’s Surface
Temperature - 1000 to 2100
• 1000 to 1861, N.
Hemisphere, proxy
data
• 1861 to 2000,
Global, instrumental
• 2000 to 2100, SRES
projections
Source: IPCC TAR 2001
20. Projected Changes in Annual Temperatures for the 2050s
The projected change is compared to the present day with a ~1% increase per year in equivalent CO2
Source: The Met Office. Hadley Center for Climate Prediction and Research
21. Sea-Level Rise Projections
• Global average
sea level is
projected to rise
by 4 to 35
inches between
1990 and 2100
• Sea level will
continue to rise
for hundreds of
years after
stabilization of
greenhouse gas
concentrations
Source: IPCC TAR 2001
22. Precipitation Projections
• Global average water vapor and global
mean precipitation will increase
• Larger year to year variations in
precipitation
23. Extreme Events
Change in Phenomenon Confidence in projected change*
Higher maximum temperatures, Very likely
more hot days
Higher minimum temperatures,
Very likely
fewer cold days and frost days
Increase of heat index Very likely, over most areas
More intense precipitation events Very likely, over many areas
Increased summer continental drying Likely, over most mid-latitude
& associated risk of drought continental interiors
Increase in tropical cyclone peak
Likely, over some areas
wind and precipitation intensities
*Judgmental estimates of confidence by IPCC: very likely - 90-99% chance,
likely - 66-90% chance.
Source: IPCC TAR 2001
24. Potential Climate Change Impacts
Health
Weather-related mortality
Infectious diseases
Air-quality respiratory illnesses
Agriculture
Crop yields
Climate Changes Irrigation demands
Forests
Temperature
Change in forest composition
Shift geographic range of forests
Forest health and productivity
Precipitation
Water Resources
Changes in water supply
Water quality
Sea Level Rise Increased competition for water
Coastal Areas
Erosion of beaches
Inundation of coastal lands
Costs to protect coastal communities
Species and Natural Areas
Shift in ecological zones
Loss of habitat and species
Source: EPA
25. Main Findings of WG II
• Climate change is underway and the early
impacts are already visible.
• Climate change and its impacts over the next
100 years will be much more significant than
what we’ve seen over the past 100 years.
• Natural systems are the most vulnerable to
climate change because of their sensitivity to
climate and limited capacity to adapt.
26. Main Findings of WG II (cont)
• More frequent and more intense weather
extremes are projected; hence, more severe
impacts from these events can be expected.
• Developing countries in general and poor
communities within developed countries are
most vulnerable.
• Adaptation can help reverse adverse impacts;
but these are costly and some damages are
inevitable.
• Win-win options are available, if action is swift.
29. The United States has 4% of the world’s population, but
produces 25% of the world’s CO2 emissions
30. Responsibility
• Some argue that wealthy countries should make
sacrifices because they
– have an ethical responsibility for historic use of
“climate space”
– have self-interest
– have the means to invest in and develop clean
technology
• Developing countries are most vulnerable, yet
have benefited least from industrial activity
31. A 1 m rise in sea level would flood 20% of Bangladesh
and displace 14.8 million people
Globally,
over 200 million people
would be displaced or
require sea walls
Huq et al. 1995
Nichols and Mimura 1998
32. “If climatic change makes our country uninhabitable,
we will march with our wet feet into your living
rooms.”
- Atiq Rahman, Bangladesh spokesman in climate negotiations, 1995
33. Kyoto Protocol
• Kyoto Protocol signed 1997
• Calls for industrial countries to reduce
emissions to 5% below 1990 levels by 2010
• After 2012 developing countries to join in
• Kyoto still unratified so not yet in force as
international treaty
34. US Climate Policy
• Reject Kyoto Protocol
• Effectively rejects climate change research
conclusions
• Voluntary, not mandatory, emissions reductions
• Focus on reducing emissions intensity, not total
emissions
• Support further research, including carbon
sequestration
35. Environmental Scientists
• What motivates scientists to choose their topic?
– Curiosity about how the world functions
– Economic, social, inertial (as in other professions)
– Desire to work in a field that “improves the world”
36. Environmental Scientists
• What are the ethical responsibilities of scientists?
– No institutionalized guidelines
– Scientists are therefore guided by personal ethics
– Many scientists would say that their strongest ethical
responsibility is to fairly and completely report their data and
conclusions
• “If it’s out there, we should be able to discover and report it”
• Should there be institutionalized ethical guidelines?
– E.g., Hippocratic oath, Professional Engineer, therapist
37. Summary
• Extensive and wide-spread evidence that the
earth is warming
• New and stronger evidence of a human
influence on climate
• Potential consequences are severe and
persistent
• Developed countries have a responsibility to
address climate change by reducing emissions,
etc., but the U.S. opposes such measures
• Despite the important implications of scientific
work, there is no ethical code of conduct for
scientists
