Planet likely to warm by ‘catastrophic’ 4C by 2100

Global temperature increases, caused by climate change, are likely to be nearer to the worst case scenario than has previously been suggested, a new study has claimed.

Researchers from the Centre for Excellence for Climate System Science at the University of New South Wales and the Pierre and Marie Curie University in Paris have found that if global carbon emissions are not reduced, temperatures across the world will increase by around 4C by 2100.

Their study, published in the journal Nature, says that our climate is more sensitive to carbon dioxide than climate models have suggested, adding that temperatures could even rise by more than 8C by 2200. 

In September, the Intergovernmental Panel on Climate Change (IPCC) set a 2C warming threshold, which could be realistically achieved if sufficient emission reductions are made, and above which global warming will seriously alter the planet’s environment.

However, the new research finds that as the planet warms, fewer clouds will form, meaning temperatures will rise further as less sunlight is reflected back into space.

“This study breaks new ground twice: first by identifying what is controlling the cloud changes and second by strongly discounting the lowest estimates of future global warming in favour of the higher and more damaging estimates”, explained Prof Steven Sherwood, lead author of the study.

He told the Guardian, “4C would likely be catastrophic rather than simply dangerous. For example, it would make life difficult, if not impossible, in much of the tropics, and would guarantee the eventual melting of the Greenland ice sheet and some of the Antarctic ice sheet. 

“Rises in global average temperatures of this magnitude will have profound impacts on the world and the economies of many countries if we don’t urgently start to curb our emissions.”

Sherwood said that he could not rule out that future temperature rises will follow more optimistic projections. However, for that to be the case, he said, “One would need to invoke some new dimension to the problem involving a major missing ingredient for which we currently have no evidence. Such a thing is not out of the question but requires a lot of faith.”

Further reading:

World experiences warmest November in 134 years

Global warming has not paused since 1998, says study

World on track to see temperatures increase by 3.6C

World on track to use up entire 21st century carbon budget by 2034

IPCC climate report: global temperatures likely to exceed 2C this century