Clouds cover about two-thirds of the planet at any moment, but as the Earth warms, they’re becoming scarcer. This risks a feedback loop of runaway warming which could push surface temperatures up by a further 8°C, according to new research.
The findings: Supercomputer simulations suggest that greenhouse gases are causing the disappearance of clouds over our oceans, and that could drastically speed up global warming over the next century, a paper in Nature Geoscience suggests. The tipping point is predicted to come once atmospheric carbon dioxide concentrations reach about 1,200 parts per million. It’s currently about 410ppm but could reach 1,200ppm within the next century.
Past disaster: This scenario would be similar to a mass extinction event that occurred about 56 million years ago during the Eocene period, according to the authors. During the so-called Paleocene–Eocene Thermal Maximum (PETM) a sudden release of carbon into the atmosphere saw temperatures suddenly leap by more than 5°C. It had catastrophic effects. It caused mass extinction in the seas and was hot enough for crocodiles to swim in the Arctic.
Time to worry? Yes, and no. The thought of life being unable to exist around the Equator is a scary prospect. It would also mean the end of human civilization, as we know it. But there are plenty of assumptions, and steps that would have to take place, before we reached that point. Your response to that might depend on how optimistic you are about the likelihood of humanity tackling climate change, before it inflicts further irreparable damage.