The beginning of July was the hottest week on record for the planet, according to the World Meteorological Organization.
The UN body said this year had already seen the hottest June on record, driven by climate change and the early stages of an El Niño weather pattern.
“The world just had the hottest week on record, according to preliminary data,” the WMO said in a statement.
The statement added that temperatures were breaking records on land and in the oceans, with 'potentially devastating impacts on ecosystems and the environment'.
“The exceptional warmth in June and at the start of July occurred at the onset of the development of El Niño, which is expected to further fuel the heat both on land and in the oceans and lead to more extreme temperatures and marine heatwaves,” said Christopher Hewitt, WMO director of climate services.
“We are in uncharted territory and we can expect more records to fall as El Niño develops further and these impacts will extend into 2024.
“This is worrying news for the planet.”
Hewitt said global sea surface temperatures were at record highs for this time of the year.
“It is not only the surface temperature, but the whole ocean is becoming warmer and absorbing energy that will remain there for hundreds of years," he said.
“If the oceans are warming considerably, that has a knock-on effect on the atmosphere, on sea ice and ice worldwide,” explained Michael Sparrow, chief of the world climate research program at the WMO.
The average global temperature on July 7 was 17.24 degrees Celsius, according to provisional analysis based on reanalysis data from Japan named JRA-3Q, This is 0.3°C above the previous record of 16.94 °C on August 16, 2016, which was a strong El Niño year.
According to the WMO, record June temperatures were experienced across northwest Europe.
Parts of Canada, the United States, Mexico, Asia, and eastern Australia were significantly warmer than normal.
However, June wasn't the hottest everywhere.
It was cooler than normal in a few places including Western Australia, the western United States, and western Russia.
Over the weekend, large parts of Europe and the United States sweltered through extreme heatwaves.
The weather centre in Italy warned Italians to prepare for 'the most intense heatwave of the summer and also one of the most intense of all time'.
The thermometer is likely to hit 40 degrees Celsius in Rome by Monday and even 43C on Tuesday, smashing the record of 40.5C set in August 2007.
A powerful heatwave stretching from California to Texas was expected to peak as the US National Weather Service warned of an 'extremely hot and dangerous weekend'.
Phoenix, Arizona, recorded 16 straight days above 43C, with temperatures hitting 43.9C on Saturday with a brutal 46C expected in the coming days.
Parts of eastern Japan are also expected to reach 38 to 39C on Sunday and Monday and monsoon rains have reportedly killed at least 90 people in northern India.
Sparrow said the effects of El Nino will be felt even more towards the end of the year.
“El Niño hasn’t really got going yet,” he said.