Eastern China looks set to sizzle again

By 2024, more than half of the summers in eastern China will be as hot as in 2013, when the region was hit by a record-breaking heatwave and devastating drought, according to a study.

Based on current global warming trends, this will occur even if rising greenhouse gas emissions are slowed over the next decade, it said.

The summer of 2013 was the hottest on record in eastern China - 1.1 degrees C above the long-term average.

On 31 days, the temperature reached or exceeded the heatwave benchmark of 35 degrees - more than double the usual June to August tally.

Nine provinces, with half a billion inhabitants, were affected. Direct economic losses in China's most populated and economically developed region have been put at 59 billion yuan ($9.6 billion).

Reporting in the journal Nature Climate Change, scientists in Beijing, Canada and the United States said the probability of a 2013-like summer in eastern China has increased considerably since the early 1950s.

The region's rapid urbanization is adding to the risk, they said.

The scientists pointed to an effect called the urban heat island, in which buildings and roads store heat during the day but fail to shed it all at night, increasing the daytime temperature bit by bit.

The team, led by Zhang Xuebin of Environment Canada in Toronto, extrapolated temperatures on the basis of the region's weather from 1955 to 2013 and on internationally used simulations for global warming.

"By 2024, at least 50 percent of summers will be as hot as the 2013 summer," they wrote.

"The increase in summer heat will inevitably lead to more widespread, long-lasting and severe heatwaves in the region," the paper warned.

"Combined with the region's rising population and wealth, it will produce higher risks for human health, agricultural systems and energy production and distribution systems if sufficient adaptation measures are not in place."