The world registered its hottest ever day on Monday as temperatures surged across the globe, according to data released by the US National Centers for Environmental Prediction (NCEP).

The United States governmental body, which delivers national and global climate guidance and forecasts from its headquarters in Maryland, said on Tuesday that it recorded an average global temperature of 17.01 degrees Celsius (62.62F) on Monday. This surpasses the previous high of 16.92 degrees Celsius (62.46F) from August 2016.

“This is not a milestone we should be celebrating,” climate scientist Friederike Otto said on Tuesday. “It’s a death sentence for people and ecosystems.”

The warning comes as many southern US states remain in the grips of extreme heat in recent days. Corpus Christi, a city in Texas, registered a record temperature in June of 51 degrees Celsius (125F). Similar temperatures have also been recorded in Oklahoma, Arkansas, Missouri and Louisiana.

China, meanwhile, has seen a prolonged heatwave, during which Beijing experienced almost ten days straight where temperatures exceeded 35 degrees Celsius (95F). Some regions in North Africa recorded temperatures approaching 50 degrees Celsius (122F).

Even Antarctica, which is currently in its winter, recently experienced relatively balmy temperatures of 8.7 degrees Celsius (47.6F), breaking its July record.

Climate scientists have said that climate change, coupled with a strong El Nino warm-weather pattern, are responsible for the unusually high temperatures – and that there is more to come.