Weather experts at the United Nations just said that the highest April temperature ever may have just been recorded—an ominous sign that comes on the heels of the monthly average concentration of carbon dioxide in the atmosphere hitting the highest level on the books.

Speaking to press at the UN headquarters in Geneva, Clare Nullis from the World Meteorological Organization (WMO) referenced the extreme heat in the Pakistani city of Nawabshah, which reportedly reached 50.2°C (122.36°F) on Monday.

"This is April—it's not June or July—it's April," Nullis said Friday. "We don't normally see temperatures above 50 degrees C. In fact, as far as we're aware, we've never seen a temperature of above 50 degrees C in April."

#Heatwave in #Pakistan Sindh province spiked 30 April with new national temperature record of 50.2°C in Sh Benazirabad (Nawabshah), says @pmdgov. #Climatechange is expected to lead to an increase in the frequency and intensity of extreme heat. pic.twitter.com/CQLzPVJB1Z — WMO | OMM (@WMO) May 3, 2018

SCROLL TO CONTINUE WITH CONTENT Never Miss a Beat. Get our best delivered to your inbox.







Earlier in the week, the Keeling Curve, which charts the daily measurement of atmospheric carbon dioxide levels taken at the Mauna Loa Observatory in Hawaii, said that April's monthly average was 410.31 parts per million (ppm). That marks the first time in recorded history that a monthly average has been above 410 ppm.

"We keep burning fossil fuels. Carbon dioxide keeps building up in the air," said Ralph Keeling, a geochemist who runs the Scripps CO2 Program and whose father created the Keeling Curve. "It's essentially as simple as that."