Earth is heating up at a faster pace than it has in 1,000 years, according to the latest figures analysed by Nasa.
The finding makes it highly unlikely that nations will be able to cap the temperature rise at the levels agreed to in the historic Paris Climate Accord last December, scientists warn.
The average global temperature of 2016 has so far peaked at 1.38C above 19th century levels, close to the 1.5C (2.7F) limit agreed to in the Paris pact. July was the hottest month ever on record.
But it is the pace of temperature increases that is worrying scientists.
"In the last 30 years we've really moved into exceptional territory," Gavin Schmidt, director of Nasa's Goddard Institute for Space Studies, told the Guardian. "It's unprecedented in 1,000 years. There's no period that has the trend seen in the 20th century in terms of the inclination [of temperatures]."
Adhering to the climate change accord limits "requires significant and very rapid cuts in carbon dioxide emissions or coordinated geoengineering, Schmidt warned, adding: "That is very unlikely."
"There's no evidence" the problem is "going away and lots of reasons to think it's here to stay," Schmidt said. "There's no pause or hiatus in temperature increase. People who think this is over are viewing the world through rose-tinted spectacles. This is a chronic problem for society for the next 100 years."
Temperature analysis by Nasa, using data from the National Oceanic and Atmospheric Administration, found that the global temperature typically rose by between 4-7C over a period of 5,000 years as the world moved out of ice ages. The temperature rise over the past century is around 10 times faster than this previous rate.
The increasing warming rate means that the world will heat up at a level "at least" 20 times faster than the historical average over the coming 100 years, according to Nasa.