Climate and the Carbon Cycle

Gretchen Keppel-Aleks

California Institute of Technology

16 October 2010

(LeQuere 2009)

Land exchange ~120 Ocean exchange ~70

Fossil Fuel Source ~8

Land Uptake ~3Ocean Uptake ~2

fluxes [PgC yr-1]

Carbon is transported through natural reservoirs: the atmosphere, the biosphere, and the ocean

The Global Carbon Cycle

Atmosphere

OceanBiosphere

Earth’s Carbon Cycle

Respiration

Decomposition

Photosynthesis

NOAA ESRL

Fluxes between the biosphere and the atmosphere set the seasonal patterns in atmospheric CO2

Earth’s Carbon Cycle

Atmospheric CO2

Respiration Photosynthesis

Earth’s Carbon Cycle

Atmospheric CO2

Temperature

Respiration Photosynthesis

?

Feedbacks between climate and the carbon cycle affect natural fluxes of CO2

Terrestrial Carbon Cycle

Atmospheric CO2

Temperature

Respiration Photosynthesis

Humidity, Precipitation,Regional Climate

???

Feedbacks between climate and the carbon cycle affect natural fluxes of CO2

Changes in the concentration of atmospheric CO2 impact the ocean

(Hoegh-Guldberg et al., 2007 , Doney et al., 2009)

Ocean CO2 and Acidification

Changes in the concentration of atmospheric CO2 impact the ocean

(Hoegh-Guldberg et al., 2007 , Doney et al., 2009)

Ocean CO2 and Acidification

Climate - Carbon Cycle Links

Carbon is present in natural reservoirs (atmosphere, ocean, biosphere)

The growth of carbon in the atmospheric reservoir is the major contributor to climate change

Climate change will affect the cycling of carbon through natural reservoirs

Understanding carbon cycle feedbacks is crucial to predicting future climate