Another El Nino problem: More carbon dioxide in air

The OCO-2 satellite can measure photosynthesis, as well as the amount of CO2 in the atmosphere, and so will shed new light on the carbon cycle. The Orbiting Carbon Observatory-2 (OCO-2) mission was created to circumvent those limitations by providing a platform with which atmospheric CO2 can be measured spectrally from space over large geographic areas, thereby offering an unprecedented capability to study, in great detail, the processes that affect the concentration of the gas over a variety of spatial and temporal scales.

In this issue, a collection of Research Articles presents the initial results from OCO-2, covering the detection of Carbon dioxide emissions from specific point sources; measurements of Carbon dioxide variations associated with El Niño, on land and at sea; and solar-induced fluorescence measurements of photosynthesis for determining gross primary production by plants.

"But during the winter, the production of Carbon dioxide by plants is minimal, and the decomposition of plant fuels the production of Carbon dioxide when the temperatures heat up".

This cycle, coupled with the continual emissions from fossil fuel burning over China, Europe and the southeast United States, means carbon levels reach a seasonal high in April in the northern hemisphere, it said.

In Africa, hotter-than-normal temperatures led to faster decomposition of dead trees and plants, releasing more carbon into the atmosphere.

Annmarie Eldering, who is the OCO-2 deputy project scientist at JPL, said, "The team's findings imply that if future climate brings more or longer droughts, as the last El Nino did, more carbon dioxide may remain in the atmosphere, leading to a tendency to further warm Earth".

According to the researchers, this change is mainly explained by a decrease of precipitation in South America and an increase in temperatures in Africa, a phenomenon that is expected to worsen by the end of the century with global warming.

Then, as spring gets under way and summer approaches, plants begin to soak up more carbon again.

In tropical Asia, the seasonal increase in Carbon dioxide emissions is explained mostly by the combustion of bio-mass.