The world has had its hottest week on record according to preliminary figures, the World Meteorological Organisation (WMO) has said.
It is the latest in a string of records that has concerned scientists about how quickly the planet is heating up on the back of human-driven climate change.
Last month was the hottest June on record, globally and for the UK, while ocean temperatures have been at their highest ever recorded since March, driven by El Nino in the Pacific and a severe marine heatwave in the North Atlantic.
Canada has been suffering from its worst ever wildfire season which has poured toxic smoke into US cities, while punishing heatwaves have swept over India, China and southern Europe, with temperatures predicted to rise to 44C in southern Spain this week.
Professor Christopher Hewitt, WMO director of climate services, said: “The exceptional warmth in June and at the start of July occurred at the onset of the development of El Nino, which is expected to further fuel the heat both on land and in the oceans and lead to more extreme temperatures and marine heatwaves.
“We are in uncharted territory and we can expect more records to fall as El Nino develops further and these impacts will extend into 2024. This is worrying news for the planet.”
Provisional assessments, based on reanalysis data from Japan known as JRA-3Q, shows the global average temperature on July 7 was 17.24C, which is 0.3C above the previous record set on August 16 2016 – the last time El Nino was present.
A reanalysis is a combination of data from satellites and computer model simulations and is typically the only available way of seeing daily global mean temperatures.
The WMO said it had not yet confirmed the Japanese reanalysis data but said it was consistent with the European Union’s climate observation satellite programme Copernicus.
Scientists from Copernicus said the North Atlantic temperature had been “off the charts”, with the Met Office saying the marine heatwave around the UK had “amplified” land temperatures to create the record-breaking June.
The Met Office also calculated that the chance of beating the previous June record had at least doubled since the 1940s and that the record could end up surpassing itself every other year by the 2050s.
Dr Michael Sparrow, head of WMO’s World Climate Research Department, said: “The temperatures in the North Atlantic are unprecedented and of great concern.
“They are much higher than anything the models predicted. This will have a knock-on effect on ecosystems and fisheries and on our weather.”
Antarctic sea ice is also at a record low, 17% below average, which has broken the previous June record by a “substantial margin”, the WMO said.
There was 2.6 million km2 of ice lost compared to the long-term average since 1979 and almost 1.2 million km2 less than the previous record set last year.
This is thought to be partly down to unusually low atmospheric pressure and El Nino combining with another meteorological effect, the Southern Annular Mode, which both exert strong influence on Antarctic sea ice extent via surface winds and sea surface temperatures, the Met Office has said.