Tropical forests absorb more Carbon Dioxide than thought: NASA

A new study of NASA highlighted that tropical forests may absorb more carbon dioxide (CO2) in response to rising atmospheric levels of the greenhouse gases than earlier thought by scientists.

The new research was published online on 28 December 2014 in the Proceedings of National Academy of Sciences. Lead author of the paper of the research is David Schimel.

Main Finding of the Study
The study suggests that the tropical forests absorb 1.4 billion metric tons of carbon dioxide out of a total global absorption of 2.5 billion, which is more than that absorbed by forests in Canada, Siberia and other northern regions, called boreal forests.

In other words, carbon absorption by boreal forests has slowed down, while in case of tropical forests, it may continue to take up carbon for many years.

What’s New in the Study
The new study is the first to devise a way to make head-to-head comparison of carbon dioxide estimates from many sources at different scales.

It reconciles results at every scale from the pores of a single leaf, where photosynthesis takes place, to the whole Earth, as air moves carbon dioxide around the globe.

The findings are advancement over the theory of carbon fertilization which says that as human-caused emissions add more carbon dioxide to the atmosphere, forests worldwide use it to grow faster, reducing the amount that stays airborne.

All else being equal, the carbon fertilization effect is stronger at higher temperatures, meaning it will be higher in the tropics than in the boreal forest.

Comment
Forests and other land vegetation currently remove up to 30 percent of human carbon dioxide emissions from the atmosphere during photosynthesis. If the rate of absorption were to slow down, the rate of global warming would speed up in return.

The findings have big implications for understanding whether global terrestrial ecosystems might continue to offset carbon dioxide emissions or might begin to exacerbate climate change.