"What we have is a strong and robust coupling between seasonal variations in atmospheric CO2 growth and tropical temperatures over the past 50 years and this provides us with a key diagnostic tool to assist in our understanding of the global carbon cycle," he said.
The team, led by Dr Weile Wang, analysed widely available data on atmospheric carbon dioxide concentration and global air temperature between 1959 and 2011.
"What we learned is that in spite of droughts, floods, volcano eruptions, El Nio and other events, the Earth system has been remarkably consistent in regulating the inter-annual variations in atmospheric carbon dioxide levels," said Dr Weile Wang, lead author of the paper.
What they found was, unlike in other parts of the planet, year-to-year changes in temperature over the tropics act in concert on both photosynthesis (absorption of carbon dioxide) and respiration (release of carbon dioxide), the two important mechanisms that naturally regulate year-to-year changes in atmospheric carbon dioxide concentrations.
"For example, a rise in temperature over the tropical regions results in a decline in photosynthesis as well as an increase in carbon losses through respiration, amplifying the temperature effect on carbon cycling" says Rama Nemani, Principal scientist for the NEX project.
|Contact: Craig Macaulay|