Heatwaves likely 'every other year' by 2030s, says Met Office study

Carbon emissions continuing at their current levels will lead to dramatic rise in severely hot weather patterns in central Europe and the Mediterranean
Arthur Neslen The Guardian 8 Dec 14;

Torrid European summers like the one in 2003 which claimed an estimated 70,000 lives are set to become a regular occurrence within two decades and the “new normal” by the end of the century, according to a new Met Office study.

The climate modelling, which was published in Nature Climate Change on Monday, foresees a dramatic rise in the chance of severely hot weather patterns in central Europe and the Mediterranean, if greenhouse gas emissions continue along their current path.

“Extremely warm summers that would occur twice a century in the early 2000s are now expected to happen twice a decade,” said Dr Nikos Christidis, the lead author of the new paper. “The chances of heatwaves as extreme as seen in 2003 have increased from about one-in-1,000 years to about one-in-100 years and are projected to occur once every other year by the 2030s-2040s under continuing greenhouse gas emissions.”

As well as the record-breaking European summer of 2003, severe heatwaves in the last decade have baked Moscow in 2010, Texas in 2011 and Australia, in its ‘angry summer’ of 2012-2013.

The odds of further extreme temperature events have already whittled rapidly since the last Met Office paper on climate change 10 years ago, Peter Stott, another of the paper’s authors, told the Guardian. “The predictions in that paper have been borne out by observations since,” he noted.

Between the Met’s 2004 climate change report looking at weather events in the 1990s and its new study, which covers the 2003-2012 period, temperatures in central Europe and the Mediterranean have risen by 0.81C.

As world leaders began arriving in Lima for talks on a new global climate treaty, the UK energy and climate change secretary, Ed Davey, said that the new research underscored the urgency of climate mitigation action.

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“This research by leading academics adds to the mounting scientific evidence that extremely damaging weather events will become more frequent and severe as a result of increasing climate change,” he said. “Time is running out and more needs to be done globally to preserve the quality of life we take for granted.”

The planetary warming trend poses a particular threat to life-sustaining infrastructure in the water-scarce Mediterranean, which is expected to be one of the regions worst-affected by climate change.

Under a business as usual scenario, the “new normal” by 2100 would be for summers 6C warmer than today across Europe, Stott said.

“By the end of the century, these sorts of changes would be threatening the ability to sustain agriculture in that part [the Mediterranean] of the world,” he said. “But for the UK too, when we get summers where we share continental weather patterns, which will still be pretty frequent, there will also be a greater risk of such heatwaves. Overall we are expecting drier, warmer summers in the UK.”

The Met Office is currently researching how jetstream variations and changes to the circulation characteristics of weather patterns may interact with climate change. These could, for instance, increase the risks of ‘blocking patterns’ that slow the movement of weather systems, allowing heatwaves to develop and intensify.