Climate Change

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Climate Change
Feb. 17, 1993
Feb. 21, 2000
Photo of glacial retreat on Mount Kilimanjaro
(Feb. 1993 to Feb. 2000) from Wikipedia Map of
Africa from www.admin.uio.no
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Weather Patterns are DynamicE.g., monthly
variation
Temperature
Image from Wikipedia (see Climate)
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Weather Patterns are DynamicE.g., monthly
variation
Precipitation
Image from Wikipedia (see Climate)
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Earths Climate is also Dynamic Climate Change
(or Variation) Characterizes Earths History
Climate Change a shift of average weather
across a region
Image from Wikipedia (see Geologic temperature
record)
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Earths Climate is also Dynamic Climate Change
(or Variation) Characterizes Earths History
E.g., Eocene temperature was 4 6 C warmer than
today
Image from Wikipedia (see Geologic temperature
record)
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Earths Climate is also Dynamic Climate Change
(or Variation) Characterizes Earths History
E.g., Eocene temperature was 4 6 C warmer than
today
Eocene on Ellesmere Island, far north Canada
Modern day on Ellesmere Island, far north Canada
Images from www.thecanadianencyclopedia.com
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Earths Climate is also Dynamic Climate Change
(or Variation) Characterizes Earths History
E.g., Eocene seas were 100 - 150 m higher than
today
Image from www.thecanadianencyclopedia.com
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Earths Climate is also Dynamic Climate Change
(or Variation) Characterizes Earths History
E.g., Milankovitch Cycles Earths changing orbit
influences temperature with 41,000 100,000 yr
periodicities
Image from Wikipedia (see Geologic temperature
record)
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Earths Climate is also Dynamic Climate Change
(or Variation) Characterizes Earths History
E.g., Pleistocene glacial and inter-glacial
periods
Image from Wikipedia (see Geologic temperature
record)
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Natural Climate Forcing(Physical processes
that influence Earths avg. temp.)
E.g., Pleistocene glacial and inter-glacial
periods
Image from Wikipedia (see Geologic temperature
record)
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Natural Climate ForcingOrbital
Owing to other planets in our solar system,
Earths orbit varies over long time
scales e.g., eccentricity varies from 0.005 to
0.058
Hypothetical circular orbit, no eccentricity
Hypothetical orbit with0.5 eccentricity
Image from Wikipedia (see Milankovitch cycles)
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Natural Climate ForcingOrbital
Earths axial tilt (obliquity) varies from 22.1
to 24.5
Image from Wikipedia (see Milankovitch cycles)
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Natural Climate ForcingOrbital
Orbital forcing causes variation in solar
heating of the planet (a.k.a. radiative forcing)
Image from Wikipedia (see Milankovitch cycles)
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Natural Climate ForcingRadiative
Image from Wikipedia (see Global Warming)
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Natural Climate ForcingRadiative
Earths avg. temp. 14 C (57 F) Without the
atmospheres greenhouse effect it would be about
-18 C (-0.4 F)
Image from www.grida.no
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Anthropogenic Causes of Climate Change
At regional scales, deforestation leads to drying
(and heating), owing primarily to reduced
evapotranspiration and water-holding capacity of
soil
E.g., much of Greece is warmer and drier today
because of deforestation in earlier millennia
E.g., cities in the Brazilian Amazon are warmer
and drier than those areas were before they
became urban centers
These examples are not global, but they
demonstrate that humans can alter regional
climate patterns
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Anthropogenic Causes of Climate Change
International Panel on Climate Change (IPCC) est.
1988 by the United Nations
Taking all the accumulated evidence into account,
anthropogenic increases in greenhouse gases are
the principal causes of global warming i.e., we
are experiencing an anthropogenically enhanced
greenhouse effect
Image from Wikipedia (see Greenhouse gas)
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Anthropogenic Causes of Climate Change
Al Gore
(b. 1948) 45th U. S. Vice President Shared
Nobel Peace Prize (2007) with IPCC Academy Award
(2007) for the documentary filmAn Inconvenient
Truth
Photo from www.thegeneralist.co.uk
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Anthropogenic Causes of Climate Change
The Keeling Curve
Image from NOAA
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Anthropogenic Causes of Climate Change
IPCC predictions are for CO2 by 2100 500 to
1000 ppm with concomitant global temperatures
1.1 to 6.4 C higher
Image from www.epa.gov
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Kyoto Protocol
Legally binding treaty (when ratified by states)
that intends to achieve stabilization of
greenhouse gas concentrations in the atmosphere
at a level that would prevent dangerous
anthropogenic interference with the climate
system"
Green signed ratified Red signed, but
not ratified Grey non-signatory
Image from Wikipedia (see Kyoto Protocol)
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Declining Glacial Thickness
Image from Wikipedia (see Global Warming)
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Feb. 17, 1993
Glacial retreat (loss) on Mt. Kilimanjaro
Feb. 21, 2000
Photo of glacial retreat on Mount Kilimanjaro
(Feb. 1993 to Feb. 2000) from Wikipedia Map of
Africa from www.admin.uio.no
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Climate Change Impacts Biota
Altered expression of traits (owing to
phenotypic plasticity e.g., phenology)
Range shifts (especially upslope and to higher
latitudes)
Adaptation (to changing environment)
Extinctions (when range shifts and adaptation
fail tokeep pace with changing environments)
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Climate Change Impacts Biota
Range map and image of polar bear (Ursus
maritimus) from Wikipedia