A recent study challenges previous assumptions about the connection between CO₂ in the atmosphere and temperatures in the tropics.
A recent study challenges previous assumptions about the connection between CO₂ in the atmosphere and temperatures in the tropics. Between 1959 and 2011, the CO₂ content in the atmosphere responded twice as strongly to temperatures in the tropics than before. This has often been attributed to increasing droughts in the tropics and to changes in carbon cycle responses caused by climate change. However, the current study conducted by researchers from the Max Planck Institute for Biogeochemistry and Leipzig University suggests that a small number of particularly strong El Niño events could be responsible for this.
Both tropical and non-tropical ecosystems absorb large amounts of carbon that were previously released into the atmosphere through human CO₂ emissions. Globally, land surface ecosystems act as a carbon sink and absorb on average around a third of human CO₂ emissions. These ecosystems are therefore a natural buffer for climate change. In the 1980s and 1990s, however, researchers observed an increased fluctuation in global carbon storage on land, and it appeared that the CO₂ growth rate was particularly sensitive to temperatures in the tropics. In a recent study, researchers from Jena and Leipzig found that this “doubling” of sensitivity was caused by the increased occurrence of El Niño events in the 1980s and 1990s compared to 1960–1979. This also includes the extreme El Niño events of 1982/83 and 1997/98. El Niño events cause severe droughts and heat waves in the tropics, which affect plant growth and thus reduce carbon uptake. In times of El Niño, vegetation even releases large amounts of carbon that would therwise be sequestered in the soil or forests. This causes the CO₂ content in the atmosphere to increase.
Read more at: Universitat Leipzig
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