Mercury hits new highs as heat waves scorch the globe

Temperatures reached new highs on Monday as heatwaves and wildfires scorched swathes of the Northern Hemisphere, forcing the evacuation of 1,200 children close to a Greek seaside resort.

Health authorities have sounded alarms from North America to Europe and Asia, urging people to stay hydrated and shelter from the burning sun, in a stark reminder of the effects of global warming.

Near Athens, a forest fire flared in strong winds by the popular beach town of Loutraki where the mayor said holiday camps for youngsters had come under threat.

"We have saved 1,200 children who were in the holiday camps," said mayor Giorgos Gkionis.

Emergency services were also battling wildfires in Kouvaras and the resorts of Lagonissi, Anavyssos and Saronida near Athens. Several homes were burned in the area, according to footage from public broadcaster ERT.

"The extreme weather ... is having a major impact on human health, ecosystems, economies, agriculture, energy and water supplies," said World Meteorological Organization (WMO) Secretary-General Petteri Taalas.

"This underlines the increasing urgency of cutting greenhouse gas emissions as quickly and as deeply as possible."

In Rome, where temperatures hit a near-record 39C on Monday, American Colman Peavy could not believe the heat as he sipped a cappuccino at a cafe with his wife Ana at the start of a two-week vacation.

"We're from Texas and it's really hot there, we thought we would escape the heat but it's even hotter here," said the 30-year-old.

It was already the world's hottest June on record, according to the EU weather monitoring service, and July looks to be readying to challenge its own record.

China reported a new high for mid-July in the northwest of the country, where temperatures reached 52.2C in the Xinjiang region's village of Sanbao, breaking the previous high of 50.6C set six years ago.

Heatstroke alerts had been issued in 32 out of Japan's 47 prefectures, mainly in central and southwestern regions.

At least 60 people were treated for heatstroke, media reported, including 51 taken to hospital in Tokyo.

In Cyprus, where temperatures are expected to remain above 40C through Thursday, a 90-year-old man died as a result of heatstroke and three other seniors were hospitalised, health officials said.

In western and southern US states, which are used to high temperatures, more than 80 million people were under advisories as a "widespread and oppressive" heatwave roasted the region.

California's Death Valley, often among the hottest places on Earth, reached a near-record 52C Sunday afternoon.

In Arizona, state capital Phoenix tied its record of 18 consecutive days above 43C (109F), as temperatures hit 45C (113F) early Monday afternoon.

The US National Weather Service predicts similar highs at least through Sunday, while warning of overnight lows remaining dangerously elevated, above 32C (90F).

"We're used to 110, 112 (degrees Fahrenheit)... But not the streaks," Nancy Leonard, a 64-year-old retiree from the nearby suburb of Peoria, told AFP. "You just have to adapt."

In Southern California, several wildfires have ignited over the past few days in rural areas east of Los Angeles.

The biggest, named the Rabbit Fire, had burned nearly 8,000 acres and was 35 percent contained on Monday morning, according to authorities.

In neighbouring Canada, 882 wildfires were active on Monday, including 579 considered out of control, authorities said.

Smoke from the fires has descended on the United States again, prompting air quality alerts across much of the northeast.

In Europe, Italians were warned to prepare for "the most intense heatwave of the summer and also one of the most intense of all time", with a red alert issued for 16 cities including Rome, Bologna and Florence.

Spain enjoyed little reprieve with temperatures of 47C in the southern town of Villarrobledo.

Along with the heat, parts of Asia have also been battered by torrential rain.