2°C global warming target will mean much higher temperatures in many regions
Global temperature targets need to be renegotiated if significant regional climate impacts are to be avoided.
At November’s COP21 climate conference in Paris, world leaders agreed plans to limit global warming to "well below" 2°C.
But a study by climate experts at ETH Zurich (Switzerland), University of New South Wales (Australia) and Loughborough University published in Nature this month shows a 2°C increase in global temperature could result in regional increases of as much as 6°C.
The impact has been illustrated by new graphical depictions of regional ‘hot spots’ in a 2°C world.
For Mediterranean countries, a global average temperature increase of 2°C could produce local temperature increases of around 3.4°C. To limit warming in this region to 2°C, the global temperature must rise by no more than 1.4°C (bearing in mind that in 2015 global warming set a new record of 1°C).
The most extreme changes may be seen in the Arctic where global warming of 2°C could see night temperatures in the far north increase by 6°C. Regions around the Arctic may have passed a 2°C temperature rise as far back as 2000 and, if emissions of greenhouse gases are not cut dramatically, areas around the Mediterranean, central Brazil and the contiguous United States could see 4°C of warming by mid-century.
The paper also highlights the impact of global temperature rises on heavy rainfall, with the majority of land areas predicted to increase.
Rob Wilby, Professor of Hydroclimatic Modelling in Loughborough University’s Geography Department helped interpret the model findings and regional consequences. He says the new figures provide policy makers with some stark messages about life in a 2°C world.
“These results show how a 2°C world might translate into regional changes in extreme temperatures and rainfall. Some countries are much more exposed than others,” he said.
“Recent flooding episodes in the UK give us an insight into just how vulnerable we are, and events like these are expected to become more frequent as the global temperature rises.
“To reduce regional impacts Governments need to set an even more ambitious target for global temperature.”
The paper Allowable CO2 emissions based on regional and impact-related climate targets was led by Prof Sonia Seneviratne from ETH Zurich with researchers from Australia's ARC Centre of Excellence for Climate System Science (ARCCSS) and Professor Rob Wilby at Loughborough University.
The above map shows coldest night temperature changes if global average temperature increases by 2°C.
Here is the key in °C: