Research points to long hot summers

Research undertaken by scientists at the Climate Change Research Centre at the University of New South Wales has warned that summer in some regions of the world will become one long heatwave even if global average temperatures rise only 2°C above pre-industrial levels, with some regions coming close to being unliveable if temperatures increase by 5°C.

Even with just a 1.5°C increase in global temperatures there are significant changes to the length, intensity and frequency of heatwaves in every part of the world.

The research, by Dr Sarah Perkins-Kirkpatrick and Peter Gibson and published in , divides the globe into 26 regions and looks at how heatwaves will change with every 1°C rise in global temperatures.

When all the regions are combined, for every 1°C of warming during summer the researchers found there would likely be:

  • An extra 14.8–28.2 heatwave days

  • Heatwaves would be 3.4–17.5 days longer

  • The peak intensity of heatwaves will increase 1.2°C–1.9°C

However, particularly fast increase in heatwave days would occur in the tropics, where some regions would experience a transition to an almost constant heatwave state with just a 2°C rise.

The research also found that with just a 1.5°C increase in global temperatures, almost all regions started to experience heatwave events every four years that once only occurred every 30 years. If global temperatures were to rise by 5°C such events would occur every year.

By dividing the globe into 26 distinct regions, the research highlighted the wide variation in heatwave responses across the world, showing there was a much sharper increase in peak temperatures of heatwaves over the Mediterranean and Central Asia.

Meanwhile, tropical regions saw many more additional heatwave days and longer continuous heatwaves than other parts of the world.

The only decline to appear across the research was the number of discrete heatwave events in two regions, Central America and Eastern Africa, although these regions also saw the greatest increase in heatwave days.

The full article, Changes in regional heatwave characteristics as a function of increasing global temperature, is available here.

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