For the workers in the Iraja district of Rio de JaneiroA seaside city in Brazil with a population of 6.7 million., it felt as if they were labouring in hell. "You sweat in the shade and, if you stay in the sun, you melt like an ice lolly," said Geraldo Lima as he loaded a truck. "Even LuciferIn Christianity, a name for the devil. was using a fan!" added musician Juninho Thybau. "He couldn't bear the heat either!" And, said 17-year-old Thiago dos Santos, "Each day's worse than the last."¹

Brazil's summer does not start for another month, but already the heat is horrifying. On Sunday it reached 42.5C - a record for November, and hot enough to fry an egg on the bonnet of a car. On Tuesday a high level of humidity meant that it felt like 58.5C.²

The National Institute of MeteorologyThe science dealing with the atmosphere and its phenomena, including both weather and climate. has issued red alerts for nearly 3,000 towns and cities, covering more than 100 million people. The alerts mean that the heat could pose a serious threat to health.

Research in the Brazilian Amazon³ has found that the mortality rate among people suffering from heart disease - particularly older ones - increases during heatwaves.

The current heatwave, which is expected to last until Friday, is partly attributed to El NinoA climate pattern that involves the unusual warming of surface waters in the tropical eastern Pacific ocean. . This phenomenon occurs at two-to-seven-year intervals and involves a rise in the temperature of the Pacific Ocean. But according to a Brazilian climate expert, Karina Bruno Lima: "The main factor truly is anthropogenicEnvironmental change caused by people. global heating."⁴

Other parts of South America are suffering too. In Paraguay the town of Filadelfia recorded a temperature of 44.4C. In Peru it reached 44.4C at Puerto Esperanza.

The northern hemisphere has also experienced extraordinary heat this year. The US saw terrible wildfires in Hawaii and California. The city of Phoenix endured several weeks of temperatures above 43C. In Death ValleyA valley in California in the Mojave Desert. It is the hottest place on Earth in the summer. the thermometer reached 52C - as it did in the Xinjiang region of China.

In Europe, there were terrifying wildfires in mainland Greece and on the island of Rhodes. Sicily recorded a temperature of 46.3C; Spain suffered what one expert called a "mega-drought". Red-alert health warnings were issued in parts of the BalkansA region of southern Europe, south of Austria and Hungary. It was traditionally seen as the meeting point between the Christian and Muslim worlds..

A new report⁵ warns that average global temperatures are likely to reach 1.5 degrees above pre-industrial levels by the mid-2030s. If that happens, parts of the planet will start to become uninhabitable - thanks not only to unbearable heat, but to flooding, sea-level rise and tropical cyclones.

"Even if we transition fairly quickly to clean energy," writes Jeff Goodell in his book The Heat Will Kill You, "half of the world's human population will be exposed to life-threatening combinations of heat and humidity by 2100."

But there are still things we can do to combat global warming. Pupils studying climate change at City of London School for Girls have launched a petition to make carbon take-out compulsory.

This would mean that companies releasing carbon into the atmosphere would have to take an equal amount out - something that would make a huge difference.

Yes: The new report warns of what could happen if global warming goes above 1.5C. But the technology exists to stop that happening - it is simply a matter of finding the political will.

No: According to the new report, at least 3.3 billion people's daily lives are "highly vulnerable" to climate change, meaning that they may well have to move to safer parts of the planet.

Or... They will, but it might not be on Earth. There is every chance that during the course of this century humans will succeed in establishing colonies on the Moon and Mars.