In the next thirty years, due to the greenhouse gases already in our atmosphere, more frequent and severe heat waves are essentially unavoidable for much of the world. The proportion of the earth subjected to extreme heat (defined as temperatures far beyond normal for summer at that latitude, currently 5% of the globe) will double by 2020, and quadruple by 2040 – regardless of immediate emissions action. We may, however, be able to mitigate the heat extremes expected in the second half of the century, if we curb our emissions acutely.
Another study released the same day reports that extreme weather events could make things worse, releasing more CO2 into the atmosphere, leading to a vicious cycle. Forest fires release huge volumes of CO2, drought restricts plant growth and therefore the planet’s vegetation’s ability to soak up CO2. In fact, because of extreme weather already occurring, our ecosystems take in about 11 billion tonnes of CO2 less than they would without the extremes.
- Climate News Network: More heatwaves by 2020 ‘almost certain’
- Environmental Research Letters: Historic and future increase in the global land area affected by monthly heat extremes
- Nature (subscription required): Climate extremes and the carbon cycle