WJRiley

Climate Change:Science and Ethical Implications

Bill Riley

Earth Sciences DivisionLawrence Berkeley National Laboratory

Acknowledgements: IPCC and UCS

Discussion Outline

• Global Climate Change– What is climate change?– Observations– Predictions and impacts

• Ethical and Political Issues

Intergovernmental Panel on Intergovernmental Panel on Climate Change (IPCC)Climate Change (IPCC)

•• Established by the UN and World Established by the UN and World Meteorological Organization in 1988Meteorological Organization in 1988

•• Assess the scientific, technical, and Assess the scientific, technical, and sociosocio--economic information relevant for economic information relevant for the understanding of the risks of the understanding of the risks of humanhuman--induced climate changeinduced climate change

•• Assessments based on published and Assessments based on published and peerpeer--reviewed literaturereviewed literature

Source: OSTP

Source: OSTP

Source: OSTP

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.

Burning of fossil fuelsBurning of fossil fuels

CO2

DeforestationDeforestationCO2

Source: IPCC TAR 2001

Greenhouse Gas Concentrations are IncreasingGreenhouse Gas Concentrations are Increasing

Carbon dioxide: +Carbon dioxide: +31%31%

Methane: +Methane: +151%151%

Nitrous oxide: +Nitrous oxide: +17%17%

Source: IPCC TAR 2001

Observed Observed Variations of the Variations of the Earth’s Surface Earth’s Surface Temperature*Temperature*

*relative to 1961*relative to 1961--1990 average1990 average

Source: IPCC TAR 2001

Observed Observed Variations of the Variations of the Earth’s Surface Earth’s Surface Temperature*Temperature*

*relative to 1961*relative to 1961--1990 average1990 average

•• Clear correlation Clear correlation between atmospheric between atmospheric COCO22 and temperature and temperature over last 160,000 yearsover last 160,000 years

•• Current level of COCurrent level of CO22 is is outsideoutside bounds of bounds of natural variabilitynatural variability

••RateRate of change of COof change of CO22is also unprecedentedis also unprecedented

Source: OSTP

If nothing is done to slow If nothing is done to slow greenhouse gas emissions. . .greenhouse gas emissions. . .

•• COCO22 concentrations will likely concentrations will likely be more than 700 ppm by 2100be more than 700 ppm by 2100

•• Global average temperatures Global average temperatures projected to increase between projected to increase between 2.5 2.5 -- 10.4°F10.4°F

2100

Main Findings of WG I Main Findings of WG I •• Extensive and wideExtensive and wide--spread evidence that the spread evidence that the

earth is warming; we are already seeing the first earth is warming; we are already seeing the first clear signals of a changing climate.clear signals of a changing climate.

•• Human activities are changing the atmospheric Human activities are changing the atmospheric concentrations of greenhouse gases.concentrations of greenhouse gases.

•• New and stronger evidence of a human influence New and stronger evidence of a human influence on climate.on climate.

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

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

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

•• Global average Global average temperature is temperature is projected to projected to increase by 2.5 increase by 2.5 to 10.4°F from to 10.4°F from 1990 to 21001990 to 2100

•• Projected rate of Projected rate of warming is warming is unprecedented unprecedented for last 10,000 for last 10,000 yearsyears

Temperature ProjectionsTemperature Projections

Source: IPCC TAR 2001

•• 1000 to 1861, N. 1000 to 1861, N. Hemisphere, proxy Hemisphere, proxy data data

•• 1861 to 2000, 1861 to 2000, Global, instrumentalGlobal, instrumental

•• 2000 to 2100, SRES 2000 to 2100, SRES projectionsprojections

Source: IPCC TAR 2001

Variations of the Earth’s SurfaceVariations of the Earth’s SurfaceTemperature Temperature -- 1000 to 21001000 to 2100

Projected Changes in Annual Temperatures for the 2050sProjected Changes in Annual Temperatures for the 2050s

The projected change is compared to the present day with a ~1% iThe projected change is compared to the present day with a ~1% increase per year in equivalent COncrease per year in equivalent CO22

Source: The Met Office. Hadley Center for Climate Prediction and Research

•• Global average Global average sea level is sea level is projected to rise projected to rise by 4 to 35 by 4 to 35 inches between inches between 1990 and 21001990 and 2100

•• Sea level will Sea level will continue to rise continue to rise for hundreds of for hundreds of years after years after stabilization of stabilization of greenhouse gas greenhouse gas concentrationsconcentrations

SeaSea--Level Rise ProjectionsLevel Rise Projections

Source: IPCC TAR 2001

Precipitation ProjectionsPrecipitation Projections

•• Global average water vapor and global Global average water vapor and global mean precipitation will increasemean precipitation will increase

•• Larger year to year variations in Larger year to year variations in precipitationprecipitation

Change in Phenomenon Confidence in projected change*

Increase in tropical cyclone peak wind and precipitation intensities Likely, over some areas

Increased summer continental drying & associated risk of drought

More intense precipitation events

Increase of heat index

Higher minimum temperatures, fewer cold days and frost days

Higher maximum temperatures, more hot days

Likely, over most mid-latitude continental interiors

Very likely, over most areas

Very likely, over many areas

Very likely

Very likely

Extreme EventsExtreme Events

*Judgmental estimates of confidence by IPCC: *Judgmental estimates of confidence by IPCC: very likelyvery likely -- 9090--99% chance,99% chance,likelylikely -- 6666--90% chance.90% chance.

Source: IPCC TAR 2001

HealthWeather-related mortalityInfectious diseasesAir-quality respiratory illnesses

AgricultureCrop yieldsIrrigation demands

Water ResourcesChanges in water supplyWater qualityIncreased competition for water

Coastal AreasErosion of beachesInundation of coastal landsCosts to protect coastal communities

ForestsChange in forest compositionShift geographic range of forestsForest health and productivity

Species and Natural AreasShift in ecological zonesLoss of habitat and species

Potential Climate Change ImpactsPotential Climate Change Impacts

Climate Changes

Sea Level Rise

Temperature

Precipitation

Source: EPA

Main Findings of WG IIMain Findings of WG II•• Climate change is underway and the early Climate change is underway and the early

impacts are already visible.impacts are already visible.•• Climate change and its impacts over the next Climate change and its impacts over the next

100 years will be much more significant than 100 years will be much more significant than what we’ve seen over the past 100 years.what we’ve seen over the past 100 years.

•• Natural systems are the most vulnerable to Natural systems are the most vulnerable to climate change because of their sensitivity to climate change because of their sensitivity to climate and limited capacity to adapt.climate and limited capacity to adapt.

Main Findings of WG II (cont)Main Findings of WG II (cont)•• More frequent and more intense weather More frequent and more intense weather

extremes are projected; hence, more severe extremes are projected; hence, more severe impacts from these events can be expected. impacts from these events can be expected.

•• Developing countries in general and poor Developing countries in general and poor communities within developed countries are communities within developed countries are most vulnerable.most vulnerable.

•• Adaptation can help reverse adverse impacts; Adaptation can help reverse adverse impacts; but these are costly and some damages are but these are costly and some damages are inevitable.inevitable.

•• WinWin--win options are available, if action is swift.win options are available, if action is swift.

Ethical and Political Issues

• National and international• Individuals

The United States has 4% of the world’s population, but produces 25% of the world’s CO2 emissions

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

A 1 m rise in sea level would flood 20% of Bangladesh and displace 14.8 million people

Huq et al. 1995Nichols and Mimura 1998

Globally,over 200 million people would be displaced or

require sea walls

“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

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

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

• 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”

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 andconclusions

• “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

Environmental Scientists

Summary•• Extensive and wideExtensive and wide--spread evidence that the spread evidence that the

earth is warmingearth is warming•• New and stronger evidence of a human New and stronger evidence of a human

influence on climateinfluence on climate•• Potential consequences are severe and Potential consequences are severe and

persistentpersistent•• Developed countries have a responsibility to Developed countries have a responsibility to

address climate change by reducing emissions, address climate change by reducing emissions, etc., but the U.S. opposes such measuresetc., but the U.S. opposes such measures

•• Despite the important implications of scientific Despite the important implications of scientific work, there is no ethical code of conduct for work, there is no ethical code of conduct for scientistsscientists