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Positive feedback
The findings are important because they point to the impacts of extensive heatwaves on grasslands and forests that together account for 20 per cent of Earth's land surface, said Arnone.
They also throw in a new factor for calculating the value of natural sinks, which play a critical role in offsetting man-made greenhouse gases.
Hot years or prolonged heatwaves, according to the IPCC, are likelier to become more frequent under climate change. In such a scenario, sinks will be less able to soak up CO2. In turn, the CO2 that is not absorbed will remain in the atmosphere rather than be sequestered in the ground, thus accelerating the greenhouse effect.
In scientific parlance, this is a 'positive feedback', or a vicious circle, likely to amplify climate damage.
