China has logged its hottest August since records began, state media reported Tuesday, following an unusually intense summer heat wave that parched rivers, scorched crops and triggered isolated blackouts.

Southern China last month sweltered under what experts said may have been one of the worst heat waves in global history, with parts of Sichuan province and the megacity of Chongqing clocking a string of days well over 40 degrees Celsius (104 Fahrenheit).

The average temperature nationwide was 22.4C in August, exceeding the norm by 1.2C, state broadcaster CCTV reported, citing the country's weather service.

Some 267 weather stations across the country matched or broke temperature records last month, the report said.

It was also China's third-driest August on record, with average rainfall 23.1 percent lower than average.

"The average number of high-temperature days was abnormally high, and regional high-temperature processes are continuing to impact our country," CCTV reported the weather service as saying.

Scientists say extreme weather like heat waves, droughts and flash floods is becoming more frequent and intense due to human-induced climate change.

Last month, temperatures as high as 45C prompted multiple Chinese provinces to impose power cuts as cities battled to cope with a surge in electricity demand partly driven by people cranking up the air conditioning.

Images from Chongqing showed a tributary of the mighty Yangtze river had almost run dry, a scene echoed further east where the waters of China's largest freshwater lake also receded extensively.

- 'Severe threat' -

Chongqing and the eastern megacity of Shanghai switched off outdoor decorative lighting to mitigate the power crunch, while authorities in Sichuan imposed industrial power cuts as water levels dwindled at major hydroelectric plants.

As local authorities warned that the drought posed a "severe threat" to this year's harvest, the central government approved billions of yuan in subsidies to support rice farmers.

"This is a warning for us, reminding us to have a deeper understanding of climate change and improve our ability to adapt to it in all respects," said Zhang Daquan, a senior official at China's National Climate Centre, in comments carried Monday by the state-run People's Daily newspaper.

"It is also necessary to raise awareness across all of society to adapt to climate change... and strive to minimise social and economic impacts and losses," Zhang said.

Higher-than-usual temperatures are also expected across China throughout September, CCTV cited the weather service's deputy director Xiao Chan as saying.

- Coal boost -

Scientists have said a rapid reduction in global carbon dioxide emissions is needed to avert potentially disastrous global heating and its associated climate impacts.

China, the world's largest greenhouse gas emitter, has pledged to bring its carbon emissions to a peak by 2030 and cut them to zero by 2060.

But the record-busting summer heat and drought, combined with a power crunch last year, have pushed authorities to pivot back towards carbon-rich coal use in what they have portrayed as a bump on the road towards a more sustainable future.

Beijing said earlier this year it would raise coal mining capacity by 300 million tonnes and has stepped up approvals of coal plants and related infrastructure.