Scorching summer heatwaves and downpours are set to become more extreme in the northern hemisphere as global warming makes weather patterns linger longer in the same place, scientists said last week in a new study.
They said there was a risk of "extreme extremes" affecting parts of Asia, North America, Europe as man-made greenhouse gas emissions seemed to be disrupting high-altitude winds that blow eastwards in vast, looping "planetary waves", reported Reuters.
"Summer weather is likely to become more persistent - more prolonged hot dry periods, possibly also more prolonged rainy periods," said Dr Dim Coumou, lead author of the study at the Potsdam Institute for Climate Impact Research (PIK) and Vrije Universiteit Amsterdam.
Both trends can lead to extremes like heat, drought, wildfires, or flooding, Dr Coumou told Reuters.
The findings were published in the journal Nature Communications.
Many parts of the northern hemisphere have experienced baking heat this summer, with wildfires from California to Greece. Even in the Arctic Circle in northern Europe, temperatures rose above 30 degrees Celsius.
Such stalling of weather patterns could threaten food production, said the study’s authors.
"Persistent hot and dry conditions in Western Europe, Russia and parts of the US threaten cereal yields in these breadbaskets," they wrote.
They linked the slowdown in weather patterns to the Arctic, which is heating at more than twice the global average amid climate change.
The difference in temperature between the chill Arctic and warmth further south is the main reason behind winds that blow weather systems around the globe, they wrote. With less contrast in temperatures, winds slow and heat or rain can linger longer.
PIK director Hans Joachim Schellnhuber, said that there is increasing evidence that humanity is messing with these enormous winds.
"Fuelled by human-made greenhouse-gas emissions, global warming is probably distorting the natural patterns," he wrote in a statement.
The extent of Arctic ice and snow has been shrinking in recent years, exposing ever more darker-coloured water and ground, which soaks up ever more heat and accelerates warming, according to the research.