lect_22_Global change

Global Carbon Cycle
Charles Keeling
C02 is not the only greenhouse gas –
Water vapor is the most potent but also the most enigmatic since
clouds can both reflect and trap heat
Methane (60x; ~15%), Nitrous Oxide (270x),…30 others
Sources of anthropogenic C02:
Coal: 41%
Oil: 39%
Natural gas: 27%
56% of all C02 humans have ever liberated is still aloft –
- contributes to 80% of Global warming
According to NOAA and NASA data,
the Earth's average surface temperature has
increased by about 1.2 to 1.4ºF since 1900.
Keep in mind that these are global averages –
some parts of the world may actually get colder
Closer to the poles the increase is more extreme –
Alice Springs, Australia has increased 5ºF over
the 20th century
The tropical Pacific ocean commonly dipped below 66.5ºF
between 1945-1955; since 1976 it has rarely dropped below
Think Global Change…
For every 18ºF the amount of water vapor the air holds
2x as much water vapor
For every 18ºF the amount of water vapor the air holds
2x as much water vapor – “Hurricane Fuel”
One gram of water evaporating from your skin transfers
580 calories of heat
Extrapolate this transfer of energy from one gram of water on
your body to an entire ocean and imagine the energy created
Its complicated: aerosols – tiny particles suspended in air –
and global dimming.
100 ppm increase in CO2 can increase surface temps by 9ºF.
Why haven’t they (1.13ºF vs 9ºF)? Aerosols
Global cooling in the 1940-70s due to high sulphur dioxide emissions
Scrubbers installed to combat acid rain turned this around
Airplane contrails create persistent cloud cover –
the grounding of US flights post 9/11 resulted in an unprecedented
increases in daytime (relative to nighttime) temps.
1991 eruption of Mt Pinatubo (Philippines) ejected 20 million tons
of sulphur dioxide – NASA predicted a 0.5ºF global cooling –
exactly as predicted
Predictions ~10 different global circulation models – the best appears to be the
Hadley Model
They all predict around a 2-5ºC increase in mean global surface temps
How will the Biological World respond?
(1) Extinction (e.g., loss of habitat)/Opportunity (gain of habitat)
(2) Range shifts – if possible
(3) changes in phenology/timing
 Major disruption as new communities are assembled
Global climate change and mammalian species diversity in U.S. national Parks.
PNAS 100:11474-11477
125-145 spp before the Polynesians arrived
71 native landbirds at the arrival of Captain Cook
Currently 23 are extinct and most remaining threatened
(10 spp haven’t been seen in 10+ years)
~ 1830, the first mosquito species, Culex quinquefaciatus, arrives
1939 Avian malaria noted
~ 1905 avian malaria parasite, Plasmodium relictum, arrives with introduced birds
Plasmodium parasites cannot develop < 13º C
Peak prevalence occurs at 17º C.
native birds
Elevation (m)
Present day and prediction of land area (km2)
on three Hawaiian Islands under a 2º C increase
<17º C (today):
< 17º C (2º C): 1171 (-38%)
7799 (-37%)
2299 (-85%)
Marmots come out of hibernation
based on temperature (too early),
since snowpack has not changed.
The absence of food/hi metabolic
puts stress on marmot populations
In contrast, ground squirrels & chipmunks hibernate 2-4 weeks longer
whereas American robins migrate to the CO Rockies ~2 weeks earlier
Climate claims the golden toad?
discovered/named in 1966 – gone ~1987.
- Pacific ocean warming
- elevated dew point
- Rising cloud line
shade, cool weather, and
rainfall patterns had not
but since 1976 the number
of mistless days increased
per year coalescing into
long enough runs for
desiccation to cause
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