Impact of climate change on Southern Ocean CO2 sink and marine ecosystems

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Impact of climate change on Southern Ocean CO2
sink and marine ecosystems Corinne Le
Quéré British Antarctic Survey and University of
East Anglia
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Atmospheric CO2 concentration (ppm)
2000
2300
CO2 emissions (GtC/y)
2000
2300
time (y)
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CO2 emissions (GtC/y)
2000
2100
Atmospheric CO2 concentration (ppm)
2000
2100
time (y)
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CO2 emissions
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CO2 emissions
Atmospheric CO2 increase
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Fraction of the CO2 emitted by human activities
which remains in the atmosphere
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energy
water
winds
observed warming trend 1979-2005
Smith and Reynolds 2005 and IPCC 2007
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atmosphere
CO2
chemical reactions

ocean
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biological activity
chemical reactions

ocean
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biological activity
chemical reactions
time scale 1 to 1000 years

time scale 1 day to a few years
ocean
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biological activity
these respond to changes in temperature
these respond to ocean acidification

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ocean acidification in a high CO2 world
largest
Orr et al. 2005
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biological activity
these respond to changes in temperature
these respond to ocean acidification
these are affected by fisheries and habitat
changes. They sustain the higher marine organisms

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Unique biodiversity
Slide from E. Murphy
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Southern Ocean
M. Racault
SeaWiFS observations
Chla anomalies (mgChl/m3)
PISCES-T model result
1965
2005
Krill density (no/m2)
Atkinson et al.,2005
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Monera (bacteria and archaea)
Proto zooplankton (ciliates, heterotrophic
flagellates)
Meso zooplankton (copepods, appendicularians,
amphipods)
Macro zooplankton (euphausids, salps, pteropods)
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conflicting information
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Meso-zooplankton biomass (mol/kg)
no biomass database for other zooplankton
Buitenhuis et al.,2005
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present
projected
IPCC 2007
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atmospheric CO2 (ppm)
380
2007
1850
280
180

650 thousand years
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• Most urgent priorities for research
• quantify and understand the trends in the ocean
  and land sinks for CO2, particularly at high
  latitudes
• gain quantitative understanding of the complex
  interactions which regulate the activity of
  marine ecosystems

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