Title: What Does Science Say About Climate Change?
1What Does Science Say About Climate Change?
- Prof. Bill Moomaw
- Fletcher School, Tufts University
- November 2004
2The Earths Climate System
- Light from the Sun is absorbed by land and water,
and is converted to heat. - Some heat is emitted back into space as radiant
heat, just as heat is radiated from hot pavement
on a July day. - Some of this radiant heat is absorbed by water
vapor and clouds, carbon dioxide, methane,
nitrous oxide and other trace atmospheric gases. - These gases act like the glass windows in a car
creating the hot car effect.
3Hot Car Effect and Climate Change
Natural
Enhanced
4Brief History of Climate Change Science
- 1827 Fourier hypothesizes greenhouse effect
- 1860 Tyndal identifies CO2 and water vapor as
heat trapping gases - 1896 Arrenhius calculates earth warming from
gases and predicts future warming from doubling
and quadrupling CO2 - 1930 Calandar shows correlation of temperature
and CO2 - 1958 Keeling begins direct measurement of CO2 in
atmosphere - 1980 to 2004 evidence accumulates
5The one constant of climate has been change by
natural forces.What is new is that human
activities are altering the composition and size
of the atmosphere, the face of the land, and the
climate system.
6What natural forces affect the climate system?
- Natural fluctuations in the suns intensity
- The complex motion of the earth around the sun
- Volcanic eruptions
- Changes in ocean currents
- Shorter-term cycles like El Nino
7What natural forces affect the climate system?
- Natural fluctuations in the suns intensity
- The complex motion of the earth around the sun
- Volcanic eruptions
- Changes in ocean currents
- Shorter-term cycles like El Nino
8What human activities are affecting climate?
- Carbon dioxide from fossil fuels release about 6
billion tons of carbon each year to the
atmosphere - Atmospheric carbon dioxide concentrations have
increased by nearly 32 - Methane from agriculture, livestock, landfills
and industry have increased by 133 - Nitrous oxide from agriculture and industry has
increased by 15 - Change in land use and land cover release
1 billion tons of carbon plus other gases
9What is the evidence for human caused climate
change?
- Direct measurement of changes in atmospheric
composition - Direct measurement of temperatures
- Direct measurement of precipitation and other
climate indicators - Direct measurement of shifts in species
- Paleoclimate records
- Climate model verification
- Testing models with other planetary climates
Venus, Mars and the moons of Jupiter Saturn
10Vostok temperature and CO2
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20Looking to the Future
- What will happen to concentrations of climate
altering gases such as carbon dioxide if we fail
to act? - What will happen to planetary temperatures if we
fail to act?
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25Major Indicators of Current Climate Change
- Average global temperature has risen by 1o F in
past 100 years with high latitude increases of 4o
F - Seasons in the US and Europe have shifted by one
week in past 50 years - Precipitation patterns are changing
- Species are migrating higher and towards the
poles
26- Sea level has risen by 6-8 in the past century
and is proceeding at a rate of more than an inch
a decade - More than 95 of worlds glaciers are retreating
- Polar sea ice has thinned by more than 40 in 30
years, and coastal ice shelves are disintegrating
in Antarctica - Permafrost is warming and melting rapidly,
destroying buildings and roads, and could disrupt
Alaska oil pipeline
27Upsala Glacier Patagonia, Argentina
28Rhone Glacier Switzerland 1930-2001
29Pasterze Glacier Austria1875-2004
30Portage Glacier Alaska1914-2004
31Recent Findings 1
- Terrence Joyce of Woods Hole Oceanographic
Institute argues that the observed slowing of the
North Atlantic conveyor could become irreversible
if pushed beyond a threshold by climate related
changes. - This would cause rapid, major drops in
temperatures in Europe and Eastern North America.
32Link of Climate Change to Security
- In February 2004, the Pentagon published a report
expressing deep concern of the political and
economic destabilization that might accompany
abrupt climate change - http//www.ems.org/climate/pentagon-climate
-change.pdf - Fortune magazine highlighted this climate change
- national security link (Fortune February 2004)
http//www - Suddenly, Prof. Wally Broeckers 1959 doctoral
dissertation idea was news!
33Recent Findings 2
- Satellite measurements of lower atmosphere
temperatures have been interpreted as rising less
since measurements began in 1979 than land and
sea surface trends. - This discrepancy has now been resolved.
- Satellite measurements were found to be measuring
part of the cooler stratosphere and not just the
lower troposphere as was thought. - There is now close agreement with land and sea
temperature trends removing another uncertainty. - QIANG FU, CELESTE M. JOHANSON, STEPHEN G.
WARREN DIAN J. SEIDEL Nature 429, 5558 (2004)
doi10.1038/nature02524 (May 6, 2004)
34Recent Findings 3
- The sustained drought in the Sahel region of
Africa that began around 1970 has continued - Not only is total rainfall decreased, but what
does occur comes in intense downbursts punctuated
by drought. - It has been confirmed that this altered weather
pattern arises from the warming of sea surface
temperature rises in the Indian Ocean. - If the sea temperature rise comes from global
warming, then we are in dire straits. - Alessandra Giannini, Columbia University Science
October 13, 2003
35Recent Findings 4
- Stratospheric ozone loss may be altering climate
- The altered amount of ozone shifts the wind
patterns around Antarctica with effects that
extend much farther. - While the Antarctic peninsula has warmed, the
center of the continent has cooled. - The warming appears to be coming from the ocean
and leading to the spectacular breakup of state
sized ice shelves. Nathan Gillett and David
Thompson Science, 10/10/03 - The cooling in the interior appears to be due to
the loss of heat through the ozone hole - Thompson, D. W. J., and S.
Solomon,Science, 296, 895-899, 2002
36Recent Findings 5
- While human activities release about 7 billion
tonnes of carbon as CO2 each year, usually half
is absorbed by the ocean, by plants and by soils. - In 2003, CO2 in the atmosphere increased
substantially above annual growth rates of the
past meaning that less is being absorbed by
terrestrial systems and oceans.
37Recent Finding No. 6
- Antarctic glaciers are accelerating their flow
into the sea (where they will accelerate the rise
in sea level) since the collapse of the Larsen
ice shelf in 2002 - Some glaciers are found to be thinning at twice
the rate they were in the 1990s - The loss of the ice shelf is believed to have
occurred because of warmer seas - R.H. Thomas, et al Science, Sept. 23, 2004
38Recent Findings 7
- Arctic Climate Impact Assessment released
November 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 3-4?C (4 to 7?F) in the past 50 years,
and are projected to rise 4-7?C (7-13?F) 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).
39So the problem of climate change is of growing
concern.What do we do about it?
40ProblemInternational agreements are not yet
implemented and the US national government favors
voluntary actions
- Solution
- Implementation without Ratification
41Options
- Use fossil fuels more efficiently
- Move from coal to oil and gas
- Extract hydrogen from fossil fuels and store the
carbon - Continue to use fossil fuels but capture and
store CO2 physically and biologically - Develop efficient market instruments to achieve
cost effective energy mix - Utilize other technologies such as nuclear, wind,
solar, biomass and geothermal energy
42Business Opportunities
- Investment in renewable energy tripled to 18
billion between 1995 and 2002 - The US once dominated wind, solar and biomass
technology, but has fallen behind countries such
as Japan, Germany Denmark and Brazil - The IPCC estimates that there is sufficient
technology available to reduce global CO2
emissions by 15 in a decade at zero or net
negative costs
43 - Fossil fuels dominate the production of
electricity (64) followed by hydro and nuclear
(17) and other renewables (2) - The growth, however, is in the reverse order
- Wind 25
- Solar 19
- Hydro 2
- Fossil fuels 0-2
44Global Trends in Energy Use 1992 - 2002
World Electricity Generation by Type 2000
Hydro
Fossil Fuels
45Lag Times
46Innovative Thinking is Needed to Address Climate
Change
- Now is the time to act, but it requires thinking
in new, creative ways - We need to replace talk with action!
- There are opportunities for all sectors of
industry and to applaud and expand the successful
measures of the innovators - There are opportunities to follow the lead of
innovative cities like Toronto who began
municipal action in 1988
47Web sites
- Photos of glaciers and other evidence of climate
change http//www.worldviewofglobalwarming.org/ind
ex.html - Summary and synthesis of scientific information
http//www.ipcc.ch - Information about Tufts efforts
http//www.tufts.edu/tie/tci