Climate Change and Human-Induced Global Warming

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Climate Change and Human-Induced Global Warming
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The Greenhouse Effect

• A normal climatic warming effect caused by
  permitting incoming solar radiation but
  inhibiting outgoing terrestrial radiation.
• Three gases are the primary cause
• Carbon Dioxide (CO2)
• Methane (CH4)
• Water Vapor (H2O)
• The effect is possible because outgoing earth
  radiation is of much longer wavelengths than
  incoming insolation and it gets caught or trapped
  in the atmosphere.

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The Greenhouse Effect

• Keeps Earths average temperature 35ºC warmer
  (16ºC now, -20 ºC otherwise)
• Human role? A heated
  debate

Venus 480ºC thick carbon
dioxide
Mars -62 ºC little carbon dioxide
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The Carbon Cycle
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b
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Now to the most ominous symptom of all a fever
thats rising fast.
The 10 hottest years on record in
order 2010 2005 1998 2003 2002 2009 2006 2007 20
04 2001
Source National Climate Data Center (NOAA).
2011. Global Surface Temperature Anomalies.
http//www.ncdc.noaa.gov/
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Note that very recent rate of increase greatly
exceeds anything in last 1000 years.
Source International Panel on Climate Change
(IPCC), 2001
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Note correlations in the data.
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650,000 years of climate and CO2
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The Earths temperature was remarkably stable
over the 10,000 years.
Source Intergovermental Arctic Climate Impact
Assessment (ACIA). 2004. http//www.acia.uaf.edu/p
ages/scientific.html
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Changes in Temperature and Solar Radiation
Milankovitch Cycles explain much (60) of the
observed temperature changes over hundreds of
thousands of years

• 40,000 year cycle /- 1.5 change in Earth's
  tilt
• 100,000 year cycle Orbital eccentricity of the
  elliptical orbit of the Earth. Shape of the orbit
  changes.
• 21,000 year cycle perihelion shifts throughout
  the year

The most recent ice age lasted 100, 000 years. We
are currently in an interglacial period called
the Holocene.
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Carbon dioxide levels are still rising in her
lungs.
We continue to increase our consumption of fossil
fuels.
Source Worldwatch Institute. 2007. Vital Signs
2007-2008.
Source U.S. Global Change Research Program.
2009. Global Climate Change Impacts in the U.S.
www.globalchange.gov.
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How much warmer will it get?
Source U.S. Global Change Research Program.
2009. Global Climate Change Impacts in the U.S.
www.globalchange.gov.
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Climate models suggest that the changes are just
beginning now and will accelerate rapidly.
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Global Warming Effects

• Human-induced rise in CO2 levels is already
  leading to increased greenhouse forcing and
  unnatural warming of atmosphere.
• Likely future effects
• Increased storminess, more droughts, more intense
  downpours
• More intense hurricanes and, possibly, tornadoes
• Rising sea level (.36 to 2.5 feet) in 100 years
  (IPCC, 2007)
• Loss of farmable land, especially in arid regions
• Extinction of thousands of species
• Loss of nearly all coral reef
• Increased range of tropical diseases
• Flooding of low-lying coastal regions
• IPCC estimate does not include Greenland Ice
  Sheet

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Warming of the climate system is unequivocal, as
is now evident from observations of increases in
global average air and ocean temperatures,
widespread melting of snow and ice, and rising
global mean sea level.
IPCC Report, 2007
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So is sea level rise happening? How much?
Sea level rise is not well understood. In their
2001 report, the Intergovernmental Panel on
Climate Change stated that global warming should
cause sea levels to rise 0.11 to 0.77 meters
(0.36 to 2.5 feet) by 2100. When added to storm
surges and high tides, these small changes may
have large effects. Moreover, because Greenlands
ice sheet is not well understood it was not
included in these estimates. It represents much
of the ice on Earth.
Source UN IPCC, 2001
Source UN IPCC, 2001
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Global Warming?

• Climate change will lead to more chaotic and
  unpredictable weather"Climate change will bring
  warm, wet weather, which will encourage plants to
  grow, followed by long periods of drought, during
  which they will burn." - Meinrat Andreae, Max
  Planck Institute for Chemistry, August 2001.

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She is already suffering frequent hot flashes,
dehydration, sweats, and chills.
Hurricane Katrina, 2005
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Glaciers are melting much faster than predicted.
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Extreme weather events are becoming more common
severe droughts, floods, fires, heat waves,
blizzards are all increasing in frequency.
Sources Min, S.-K. et al. Nature 470, 378-381
(2011) Pall, P. et al. Nature 470, 382-385
(2011) Stott, P. A. et al. Nature 432, 610-614 
Lake Hindmarsh, Victoria, Australia. May, 2007
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Queensland, Australia. January, 2011
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40,000 50,000 people died as a result of the
record heat wave that scorched Europe in August
2003.
It was the hottest summer in Europe in 1500
years.
France, 2003
Source Larsen, J. Earth Policy Institute. 2006.
Setting the Record Straight More than 52,000
Europeans Died from Heat in Summer 2003.
http//www.earth-policy.org/index.php?/plan_b_upda
tes/2006/update56
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Station Fire, 2009
One degree of temperature change in the last 100
years has led to four times as many fires in the
American West.
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Surface water will decrease in the U.S. Southwest.
Source U.S. Global Change Research Program.
2009. Global Climate Change Impacts in the U.S.
www.globalchange.gov.
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Global temperature change will vary

• Sea surface temperatures will also increase as
  oceans absorb more heat.
• May not have more storms, but storms will be
  stronger and longer

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Projected changes in precipitation

• High latitudes increased precipitation
• Low and middle latitudes decreased
  precipitation will worsen water shortages in
  developing countries

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U.S. Global Change Research Program (2008)

• Highlighted past effects and predicted future
  impacts of climate change in U.S.

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Are we responsible for climate change?

• The IPCC 2007 report concluded that it is more
  than 90 likely that most global warming is due
  to humans.
• In 2005, the national academies of 11 nations
  issued a joint statement urging political leaders
  to take action. By 2010 more than 30 countries
  National Academies of Science had such
  statements.
• The debate on climate change is fanned and funded
  by corporate and oil industry skeptics. The
  science is clear and unequivocal.
• The majority of signatories argued that this
  figure should have been 99, but China, among
  others, protested.