Five per cent chance of global warming being kept below two degrees, study shows
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A University of Washington study has found that the chances of global warming being kept below two degrees Celsius – a prime target of the Paris Agreement – are vanishingly small.
The researchers used statistical projections based on the total population of the world, GDP per capita and carbon intensity - the amount of carbon emitted for each dollar of economic activity.
They found that there was only a five per cent chance that temperature increases over the next century could be kept to two degrees Celsius or below. The most likely scenario is a temperature increase of between two and 4.9 degrees, with an estimated 90 per cent probability.
“Our analysis shows that the goal of two degrees is very much a best-case scenario,” said Professor Adrian Raftery, a University of Washington Professor of Statistics and Sociology and lead author of the Nature Climate Change study.
“It is achievable, but only with major, sustained effort on all fronts over the next 80 years.”
A global increase of two degrees Celsius has been described as a “tipping point” to be avoided at almost any cost. The 2015 Paris Agreement – from which US President Donald Trump recently withdrew his country, in a blow to the rest of the world – aims to limit greenhouse gas emissions in order to keep warming “well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5°C” and reduce the impact of climate change.”
The chance of temperature rises remaining below 1.5 degrees, the study found, was just one per cent.
World greenhouse gas emissions are at approximately 54 billion tonnes per year, according to the UN Environment Programme, and must be cut to 42 billion tonnes – more than a fifth – by 2030 in order to retain a temperature rise in accordance with the Paris Agreement.
Limiting future warming must involve increased efforts to improve carbon efficiency, Professor Raftery told the Thomson Reuters Foundation.
“Countries need to change the economic incentives for producing carbon – for example, by introducing a carbon tax – and encourage innovation that would improve energy efficiency […] We should be learning more from countries that are particularly carbon-efficient, like France, which has a very low-carbon transport infrastructure.”
Missing this target, the study authors warn, will have enormous consequences for people and economies around the world. Rising sea levels could cause entire regions to be flooded or submerged, while prolonged periods of droughts and other extreme weather could cause widespread famine and human misery.
A different study published in the Proceedings of the National Academy of Sciences, for instance, has linked rising global temperatures with suicides of agriculturalists in developing countries.
The researchers behind the study found that seven per cent of suicides in India can be attributed to climate change, with unseasonal rains and droughts leading to crop failures. Most of these suicides were associated with bankruptcy and debt, the data showed.
More than half of all Indians depend on agriculture for their livelihoods, making the population particularly vulnerable to the impact of climate change. While the Indian Government has announced protections for farmers, such as crop insurance schemes, farmers’ unions are critical of these actions as insufficient.