Tropical ecosystems regulate variations in Earth's carbon dioxide levels

Space Daily via SPX: The study, published in the journal Proceedings of the National Academy of Sciences, found that a temperature anomaly of just 1+ C (in near surface air temperatures in the tropics) leads to a 3.5-Petagram (billion tonnes of carbon) anomaly in the annual CO2 growth rate, on average. This is the equivalent of 1/3 of the annual global emissions from the combustion of fossil fuels and deforestation together.

Importantly, the NASA Earth Exchange (NEX) study results provide scientists with a new diagnostic tool to understand the global carbon cycle as it undergoes major changes due to the influences of human activities.

NASA study co-author, CSIRO's Dr Pep Canadell, said that the study's 50-year analysis centred on temperature and rainfall patterns during El Nino years, when temperatures increase in tropical regions and rainfall decreases. An accompanying analysis assessed the effects of volcanic eruptions, which lead to decreased temperatures due to volcanic aerosols in the atmosphere.

"Our study indicates that carbon exchanges in tropical ecosystems are extremely sensitive to temperature, and they respond with the release of emissions when warmer temperatures occur".

..."Warming is the one thing that we know with most certainty will occur under climate change in the tropics, but there are still large uncertainties about the future precipitation in tropical regions," says Dr Canadell, who is also Executive Director of the Canberra-based Global Carbon Project....

Amazon deforestation, via NASA