We Just Lived Through the Hottest September Ever Recorded

The heat has fueled fires, one of the most active Atlantic hurricane seasons and melting Arctic sea ice

The Glass Fire burns behind Merus Wines vineyards in Napa Valley, California on September 27, 2020
Fires scorched the West in last month, the hottest September on record. Photo by SAMUEL CORUM/AFP via Getty Images

Last month was the hottest September ever recorded on Earth, according to data released by Europe’s Copernicus Climate Change Service.

The global average temperature exceeded the previous record, which was set in 2019, by 0.09 degrees Fahrenheit (0.05 degrees Celsius), and was 1.13 degrees Fahrenheit (0.63 degrees Celsius) warmer than the average September based on data spanning 1979 to 2010, reports Veronica Penney for the New York Times.

That extra heat fueled wildfires in California, one of the most active Atlantic hurricane seasons on record, and heatwaves in Europe, Australia and the Middle East, writes Rob Picheta for CNN. So far, three of the nine elapsed months of 2020 have broken global records for average temperature, per CNN, marking a clear and undeniable warming trend driven by greenhouse gas emissions stemming from human activities.

Arctic sea ice also reflected the unprecedented warmth, melting back to its second lowest extent since satellite records began, reports Roger Harrabin for BBC News. Climate research suggests that as soon as 2050, Arctic ice may melt away completely during summer, according to the Times.

The United States’ National Oceanic and Atmospheric Administration (NOAA) is expected to publish its own monthly assessment in a week or so, and though the methodologies used by the two agencies differ their results typically agree. “Even though the details of the report are different, they all come to the same conclusion that the global temperatures are increasing,” Ahira Sánchez-Lugo, a physical scientist for NOAA’s National Centers for Environmental Information, tells the Times.

NOAA’s predictions suggest, with 99.9 percent certainty, that 2020 is going to be one of the five hottest years ever recorded, reports Emma Newburger for CNBC. If this prediction comes true, 2020 will maintain the veracity of a sobering factoid for another year: each of the last five years has been one of the five hottest years ever recorded globally, per Climate Central.

“We have been saying this for decades–more and more greenhouse gases will lead to more and more warming,” Ed Hawkins, a climate scientist from Reading University, tells BBC News.

Hawkins adds that 2020’s extremes, from blistering heat to hurricanes and torrential downpours, have emerged with just one degree Celsius of warming (1.8 degrees Fahrenheit) above long-term global averages. If current greenhouse gas emission trends continue, the world is on pace for three degrees Celsius (5.4 degrees Fahrenheit) of warming, Hawkins tells BBC News.

“One degree of heating is dangerous for some people, as we've seen,” Hawkins says. “Two degrees is more dangerous still, and three degrees even more dangerous. We really don’t want to find out what that’ll be like.”

Get the latest stories in your inbox every weekday.