"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."
Last year is currently the warmest year on record, itself beating a landmark set in 2014.
"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."
The increasing pace of warming means that the world will heat up at a rate "At least" 20 times faster than the historical average over the coming 100 years, according to Nasa.
While it's still difficult to compare a single year to another prior to the 19th century, a Nasa reconstruction shows that the pace of temperature increase over recent decades outstrips anything that has occurred since the year 500.