Watching the Planet Breathe: Global CO2 Monitoring from Space
CO2 can enter the atmosphere from a variety of sources, which can be natural or anthropogenic. For example, some natural sources are rotting plants, forest fires and ordinary breathing. Automobiles, factories and home heating units burn fossil fuels such as oil, coal and natural gas. Burning these fossil fuels releases CO2 into the atmosphere. These activities add to the emission of CO2 into the atmosphere.
Processes that absorb CO2 from the atmosphere are often referred to as sinks. Several natural processes remove CO2 from the atmosphere. Plants, for example, use sunlight to photosynthesize CO2 and water into sugar and other carbohydrates. Oceans also absorb atmospheric CO2, whereafter, sea creatures incorporate the dissolved CO2 into their shells. After these creatures die, their shells fall to the bottom of the ocean and eventually form carbonate rocks. The complete process of CO2 exchange (taking into account both sources and sinks) is known as the carbon cycle.
in 2009, the Japanese satellite Greenhouse Gases Observing Satellite
(GOSAT) has the ability to pick up this glow. Using GOSAT data, JPL
scientist Christian Frankenberg and colleagues have shown that it is
possible to pick up this fluorescent glow from space over the entire
planet, and thereby infer details about the health and activity of
vegetation on the ground.
(A) Global map of plant chlorophyll fluorescence as measured by the GOSAT satellite from June 2009 to May 2010. The fluorescence is measured at a spectral wavelength of 757 nanometers and superimposed on a 2°x 2° grid. Areas of higher and lower plant activity can be seen in different parts of the world. (B) Time variations in the fluorescence signal given off by vegetation, from June 2009 to August 2010. A pronounced seasonal variation can be seen that reflects the growing season in the northern hemisphere and seasonal vegetation shifts in the tropics.
GOSAT and OCO-2 will provide an unprecedented amount of information on
the health of plants and carbon dioxide levels of our planet. The hope
is that this will give us a much better grip on the Earth’s carbon cycle
-- and therefore climate change.