What Does Science Say What Does Science Say About Climate Change?About Climate Change?

Prof. Bill MoomawProf. Bill Moomaw

Fletcher School, Tufts UniversityFletcher School, Tufts University

November 2004November 2004

The Earth’s Climate SystemThe Earth’s Climate System

Light from the Sun is absorbed by land and Light from the Sun is absorbed by land and water, and is converted to heat.water, and is converted to heat.

Some heat is emitted back into space as radiant Some heat is emitted back into space as radiant heat, just as heat is radiated from hot pavement heat, just as heat is radiated from hot pavement on a July day.on a July day.

Some of this radiant heat is absorbed by water Some of this radiant heat is absorbed by water vapor and clouds, carbon dioxide, methane, vapor and clouds, carbon dioxide, methane, nitrous oxide and other trace atmospheric gases.nitrous oxide and other trace atmospheric gases.

These gases act like the glass windows in a car These gases act like the glass windows in a car creating the “creating the “hot car effecthot car effect.”.”

““Hot Car” Effect and Climate ChangeHot Car” Effect and Climate Change

Natural Enhanced

Brief History of Climate Brief History of Climate Change ScienceChange Science

1827 Fourier hypothesizes greenhouse effect1827 Fourier hypothesizes greenhouse effect 1860 Tyndal identifies CO1860 Tyndal identifies CO22 and water vapor as heat and water vapor as heat

trapping gasestrapping gases 1896 Arrenhius calculates earth warming from gases 1896 Arrenhius calculates earth warming from gases

and predicts future warming from doubling and and predicts future warming from doubling and quadrupling COquadrupling CO22

1930 Calandar shows correlation of temperature and 1930 Calandar shows correlation of temperature and COCO22

1958 Keeling begins direct measurement of CO1958 Keeling begins direct measurement of CO22 in in atmosphereatmosphere

1980 to 2004 evidence accumulates1980 to 2004 evidence accumulates

The one The one constantconstant of climate of climate has been has been changechange by natural by natural forces.forces.

What is What is newnew is that is that human human activitiesactivities are altering the are altering the composition and size of the composition and size of the atmosphere, the face of the atmosphere, the face of the land, and the climate system.land, and the climate system.

What natural forces affect the What natural forces affect the climate system?climate system?

Natural fluctuations in the sun’s intensityNatural fluctuations in the sun’s intensity The complex motion of the earth around The complex motion of the earth around

the sunthe sun Volcanic eruptionsVolcanic eruptions Changes in ocean currentsChanges in ocean currents Shorter-term cycles like El NinoShorter-term cycles like El Nino

What natural forces affect the What natural forces affect the climate system?climate system?

Natural fluctuations in the sun’s intensityNatural fluctuations in the sun’s intensity The complex motion of the earth around The complex motion of the earth around

the sunthe sun Volcanic eruptionsVolcanic eruptions Changes in ocean currentsChanges in ocean currents Shorter-term cycles like El NinoShorter-term cycles like El Nino

What human activities are What human activities are affecting climate?affecting climate?

Carbon dioxide from fossil fuels release about 6 Carbon dioxide from fossil fuels release about 6 billion tons of carbon each year to the billion tons of carbon each year to the atmosphere atmosphere

Atmospheric carbon dioxide concentrations Atmospheric carbon dioxide concentrations have increased by nearly 32%have increased by nearly 32%

Methane from agriculture, livestock, landfills and Methane from agriculture, livestock, landfills and industry have increased by 133%industry have increased by 133%

Nitrous oxide from agriculture and industry has Nitrous oxide from agriculture and industry has increased by 15%increased by 15%

Change in land use and land cover release Change in land use and land cover release 1 billion tons of carbon plus other gases1 billion tons of carbon plus other gases

What is the evidence for human What is the evidence for human caused climate change?caused climate change?

Direct measurement of changes in atmospheric Direct measurement of changes in atmospheric compositioncomposition

Direct measurement of temperaturesDirect measurement of temperatures Direct measurement of precipitation and other Direct measurement of precipitation and other

climate indicatorsclimate indicators Direct measurement of shifts in speciesDirect measurement of shifts in species Paleoclimate recordsPaleoclimate records Climate model verificationClimate model verification Testing models with other planetary climates: Testing models with other planetary climates:

Venus, Mars and the moons of Jupiter & SaturnVenus, Mars and the moons of Jupiter & Saturn

Vostok temperature and COVostok temperature and CO22

Looking to the FutureLooking to the Future

What will happen to concentrations of What will happen to concentrations of climate altering gases such as carbon climate altering gases such as carbon dioxide if we fail to act?dioxide if we fail to act?

What will happen to planetary What will happen to planetary temperatures if we fail to act? temperatures if we fail to act?

Major Indicators of Current Major Indicators of Current Climate Change Climate Change

Average global temperature has risen by Average global temperature has risen by 11oo F in past 100 years with high latitude F in past 100 years with high latitude increases of 4increases of 4oo F F

Seasons in the US and Europe have Seasons in the US and Europe have shifted by one week in past 50 years shifted by one week in past 50 years

Precipitation patterns are changingPrecipitation patterns are changing Species are migrating higher and towards Species are migrating higher and towards

the poles the poles

Sea level has risen by 6-8” in the past Sea level has risen by 6-8” in the past century and is proceeding at a rate of more century and is proceeding at a rate of more than an inch a decade than an inch a decade

More than 95% of world’s glaciers are More than 95% of world’s glaciers are retreatingretreating

Polar sea ice has thinned by more than 40% Polar sea ice has thinned by more than 40% in 30 years, and coastal ice shelves are in 30 years, and coastal ice shelves are disintegrating in Antarcticadisintegrating in Antarctica

Permafrost is warming and melting rapidly, Permafrost is warming and melting rapidly, destroying buildings and roads, and destroying buildings and roads, and could could disrupt Alaska oil pipelinedisrupt Alaska oil pipeline

Upsala Glacier Upsala Glacier Patagonia, ArgentinaPatagonia, Argentina

Rhone Glacier Switzerland 1930-2001Rhone Glacier Switzerland 1930-2001

Pasterze Glacier AustriaPasterze Glacier Austria1875-20041875-2004

Portage Glacier AlaskaPortage Glacier Alaska1914-20041914-2004

Recent Findings 1Recent Findings 1

Terrence Joyce of Woods Hole Oceanographic Terrence Joyce of Woods Hole Oceanographic Institute argues that the observed slowing of the Institute argues that the observed slowing of the North Atlantic conveyor could become irreversible if North Atlantic conveyor could become irreversible if pushed beyond a threshold by climate related pushed beyond a threshold by climate related changes.changes.

This would cause rapid, major drops in This would cause rapid, major drops in temperatures in Europe and Eastern North temperatures in Europe and Eastern North America.America.

Link of Climate Change to Link of Climate Change to SecuritySecurity

In February 2004, the Pentagon published a In February 2004, the Pentagon published a report expressing deep concern of the political report expressing deep concern of the political and economic destabilization that might and economic destabilization that might accompany abrupt climate changeaccompany abrupt climate change

: http://www.ems.org/climate/pentagon-climate-change.pdf

Fortune magazine highlighted this climate Fortune magazine highlighted this climate change - national security link (change - national security link (Fortune February 2004)Fortune February 2004): http://www

Suddenly, Prof. Wally Broecker’s 1959 doctoral Suddenly, Prof. Wally Broecker’s 1959 doctoral dissertation idea was news!dissertation idea was news!

Recent Findings 2Recent Findings 2 Satellite measurements of lower atmosphere Satellite measurements of lower atmosphere

temperatures have been interpreted as rising less temperatures have been interpreted as rising less since measurements began in 1979 than land and since measurements began in 1979 than land and sea surface trends. sea surface trends.

This discrepancy has now been resolved.This discrepancy has now been resolved. Satellite measurements were found to be Satellite measurements were found to be

measuring part of the cooler stratosphere and not measuring part of the cooler stratosphere and not just the lower troposphere as was thought.just the lower troposphere as was thought.

There is now close agreement with land and sea There is now close agreement with land and sea temperature trends removing another uncertainty.temperature trends removing another uncertainty.

QIANG FU, CELESTE M. JOHANSON, STEPHEN G. WARREN & DIAN J. SEIDEL Nature 429, 55–58 (2004); doi:10.1038/nature02524 (May 6, 2004)

Recent Findings 3Recent Findings 3

The sustained drought in the Sahel region of The sustained drought in the Sahel region of Africa that began around 1970 has continuedAfrica that began around 1970 has continued

Not only is total rainfall decreased, but what Not only is total rainfall decreased, but what does occur comes in intense downbursts does occur comes in intense downbursts punctuated by drought.punctuated by drought.

It has been confirmed that this altered weather It has been confirmed that this altered weather pattern arises from the warming of sea surface pattern arises from the warming of sea surface temperature rises in the Indian Ocean.temperature rises in the Indian Ocean.

““If the sea temperature rise comes from global If the sea temperature rise comes from global warming, then we are in dire straits.” warming, then we are in dire straits.”

Alessandra Giannini, Columbia University Science October 13, 2003

Recent Findings 4Recent Findings 4 Stratospheric ozone loss may be altering climate Stratospheric ozone loss may be altering climate The altered amount of ozone shifts the wind The altered amount of ozone shifts the wind

patterns around Antarctica with effects that extend patterns around Antarctica with effects that extend much farther.much farther.

While the Antarctic peninsula has warmed, the While the Antarctic peninsula has warmed, the center of the continent has cooled. center of the continent has cooled.

The warming appears to be coming from the The warming appears to be coming from the ocean and leading to the spectacular breakup of ocean and leading to the spectacular breakup of state sized ice shelves. state sized ice shelves. Nathan Gillett and David Thompson Science, 10/10/03

The cooling in the interior appears to be due to The cooling in the interior appears to be due to the loss of heat through the ozone holethe loss of heat through the ozone hole

Thompson, D. W. J., and S. Solomon,Science, 296, 895-899, 2002

Recent Findings 5Recent Findings 5

While human activities release about 7 While human activities release about 7 billion tonnes of carbon as CObillion tonnes of carbon as CO22 each year, each year, usually half is absorbed by the ocean, by usually half is absorbed by the ocean, by plants and by soils.plants and by soils.

In 2003, COIn 2003, CO22 in the atmosphere increased in the atmosphere increased substantially above annual growth rates of substantially above annual growth rates of the past meaning that less is being the past meaning that less is being absorbed by terrestrial systems and absorbed by terrestrial systems and oceans. oceans.

Recent Finding No. 6Recent Finding No. 6

Antarctic glaciers are accelerating their Antarctic glaciers are accelerating their flow into the sea (where they will flow into the sea (where they will accelerate the rise in sea level) since the accelerate the rise in sea level) since the collapse of the Larsen ice shelf in 2002collapse of the Larsen ice shelf in 2002

Some glaciers are found to be thinning at Some glaciers are found to be thinning at twice the rate they were in the 1990stwice the rate they were in the 1990s

The loss of the ice shelf is believed to The loss of the ice shelf is believed to have occurred because of warmer seashave occurred because of warmer seas

R.H. Thomas, et al R.H. Thomas, et al Science, Sept. 23, 2004Science, Sept. 23, 2004

Recent Findings 7Recent Findings 7

Arctic Climate Impact Assessment released Arctic Climate Impact Assessment released November 8November 8 “The Arctic is warming much more rapidly than previously

known, at nearly twice the rate as the rest of the globe..” In Alaska, Western Canada, and Eastern Russia average

winter temperatures have increased as much as 3-4C (4 to 7F) in the past 50 years, and are projected to rise 4-7C (7-13F) over the next 100 years.

Greenland ice is melting and contains enough melt water to eventually raise sea level by about 7 meters (about 23 feet).

So the problem of climate So the problem of climate change is of growing change is of growing

concern.concern.

What do we do about it?What do we do about it?

Problem:Problem:International agreements are International agreements are not yet implemented and the not yet implemented and the

US national government US national government favors voluntary actionsfavors voluntary actions

Solution: Solution:

Implementation without RatificationImplementation without Ratification

OptionsOptions

Use fossil fuels more efficientlyUse fossil fuels more efficiently Move from coal to oil and gasMove from coal to oil and gas Extract hydrogen from fossil fuels and store the Extract hydrogen from fossil fuels and store the

carboncarbon Continue to use fossil fuels but capture and Continue to use fossil fuels but capture and

store COstore CO22 physically and biologically physically and biologically

Develop efficient market instruments to achieve Develop efficient market instruments to achieve cost effective energy mixcost effective energy mix

Utilize other technologies such as nuclear, wind, Utilize other technologies such as nuclear, wind, solar, biomass and geothermal energysolar, biomass and geothermal energy

Business OpportunitiesBusiness Opportunities

Investment in renewable energy tripled to $18 Investment in renewable energy tripled to $18 billion between 1995 and 2002billion between 1995 and 2002

The US once dominated wind, solar and The US once dominated wind, solar and biomass technology, but has fallen behind biomass technology, but has fallen behind countries such as Japan, Germany Denmark countries such as Japan, Germany Denmark and Brazil and Brazil

The IPCC estimates that there is sufficient The IPCC estimates that there is sufficient technology available to reduce global COtechnology available to reduce global CO22 emissions by 15% in a decade at zero or net emissions by 15% in a decade at zero or net negative costsnegative costs

Fossil fuels dominate the production of electricity Fossil fuels dominate the production of electricity (64%) followed by hydro and nuclear (17%) and (64%) followed by hydro and nuclear (17%) and other renewables (2%)other renewables (2%)

The growth, however, is in the reverse orderThe growth, however, is in the reverse order Wind 25%Wind 25% Solar 19%Solar 19% Hydro 2%Hydro 2% Fossil fuels 0-2%Fossil fuels 0-2%

2%

17% 17%

64%

0%

10%

20%

30%

40%

50%

60%

70%

Non-hydrorenewables

Nuclear

25.4%

19.0%

1.9% 1.8% 1.6% 0.6% 0.0%

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

Wind SolarPV

Hydro Oil NaturalGas

Nuclear Coal

Global Trends in Energy Use1992 - 2002

World Electricity Generation by Type2000

Hydro Fossil Fuels

Lag TimesLag Times

Innovative Thinking is Needed to Innovative Thinking is Needed to Address Climate ChangeAddress Climate Change

Now is the time to act, but it requires Now is the time to act, but it requires thinking in new, creative waysthinking in new, creative ways

We need to replace talk with action!We need to replace talk with action! There are opportunities for all sectors of There are opportunities for all sectors of

industry and to applaud and expand the industry and to applaud and expand the successful measures of the innovatorssuccessful measures of the innovators

There are opportunities to follow the lead There are opportunities to follow the lead of innovative cities like Toronto who began of innovative cities like Toronto who began municipal action in 1988municipal action in 1988

Web sitesWeb sites

Photos of glaciers and other evidence of climate change http://www.worldviewofglobalwarming.org/index.html

Summary and synthesis of scientific information http://www.ipcc.ch

Information about Tufts efforts http://www.tufts.edu/tie/tcihttp://www.tufts.edu/tie/tci