The tropical carbon cycle has become doubly sensitive to temperature variations over the past 50 years, University of Exeter researchers find.
According to a press release, a one degree rise in temperature now results in the release of more than two billion extra tones of carbon into the atmosphere. Many Earth System Model stimulations have stated that the tropical land ecosystems' ability to store carbon will decline over the 21st century but have failed to capture the speed at which these ecosystems are rapidly becoming extremely sensitive to rising temperatures.
Researchers from the University of Exeter found that if existing stimulations could capture this sensitivity, it would be easier to predict future climate change.
"The increase in carbon dioxide variability in the last few decades suggests that tropical ecosystems have become more vulnerable to warming," Professor Peter Cox, from the University of Exeter said in the statement. "Current land carbon cycle models do not show this increase over the last 50 years, perhaps because these models underestimate emerging drought effects on tropical ecosystems. This enhancement is very unlikely to have resulted from chance, and may provide a new perspective on a possible shift in the terrestrial carbon cycle over the past five decades."
Carbon is present in all living things, carbon dioxide in the atmosphere and dissolved in water, fossil fuels and dead organic matter. Through the natural course of life and death this carbon moves through the environment in a process known as the carbon cycle. The carbon cycle circulates relatively quickly and released carbon is easily reabsorbed by the earth's environment, leaving the process in a state of equilibrium. However, burning of fossil fuels unbalances this.
Fossil fuels are formed from animals and plants that died millions of years ago. When they are extracted and burned they release carbon atoms that were absorbed in ancient times, adding volumes of carbon that would not naturally be present in the atmosphere today. The environment is unable to absorb this excess carbon, which subsequently builds up, contributing to climate change.
Findings of the study were published in the leading academic journal Nature.
