What Does Science Say About Climate Change?

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What Does Science Say About Climate Change?

• Prof. Bill Moomaw
• Fletcher School, Tufts University
• November 2004

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The 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.

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Hot Car Effect and Climate Change
Natural
Enhanced
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Brief 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

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The 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.
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What 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

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What 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

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What 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

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What 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

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Vostok temperature and CO2
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Looking 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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Major 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

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• 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

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Upsala Glacier Patagonia, Argentina
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Rhone Glacier Switzerland 1930-2001
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Pasterze Glacier Austria1875-2004
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Portage Glacier Alaska1914-2004
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Recent 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.

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Link 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!

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Recent 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)

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Recent 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

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Recent 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

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Recent 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.

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Recent 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

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Recent 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).

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So the problem of climate change is of growing
concern.What do we do about it?
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ProblemInternational agreements are not yet
implemented and the US national government favors
voluntary actions

• Solution
• Implementation without Ratification

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Options

• 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

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Business 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

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• 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

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Global Trends in Energy Use 1992 - 2002
World Electricity Generation by Type 2000
Hydro
Fossil Fuels
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Lag Times
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Innovative 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

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Web 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