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July was so hot that scientists think it has already been the hottest month ever

The announcement from the World Meteorological Organization came the same day that President Joe Biden took steps intended to protect workers from extreme heat.
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The first three weeks of July have been so warm that it’s almost certain the month will become the hottest ever recorded, the World Meteorological Organization announced Thursday.

Last month was the hottest June ever. 

“Record-breaking temperatures are part of the trend of drastic increases in global temperatures,” Carlo Buontempo, the director of the Copernicus Climate Change Service, said in a news release, adding that human-caused emissions are the “main driver” of rising temperatures. 

Copernicus, part of the European Union’s space program, performs satellite observations of Earth. The new monthly record is based on climate reanalysis data, which combines on-the-ground observations, satellite data and climate modeling to produce estimates of temperatures across the Earth that date back decades. The approach fills gaps in the observational record, and it is used by scientists worldwide to evaluate the impacts of climate change.

Global daily surface air temperature (°C) from January 1940 to July 2023, plotted as time series for each year. 2023 and 2016 are shown with thick lines shaded in bright red and dark red, respectively.
Global daily surface air temperature (°C) from January 1940 to July 2023, plotted as time series for each year. 2023 and 2016 are shown with thick lines shaded in bright red and dark red, respectively.World Meteorological Organization

The data says global mean temperatures on Earth’s surface were just above 62.5 degrees Fahrenheit through Sunday, exceeding the previous high of 61.9 degrees from July 2019. 

The Biden administration announced Thursday that it had directed the Department of Labor to focus on heat injuries in the workplace. The department issued a heat hazard alert Thursday to remind employers of their obligations.

"We wanted to make sure that all workers understood the dangers of extreme heat, and that employers understood their obligations to help prevent injury, illness and fatalities," Acting Secretary of Labor Julie Su told NBC News.

Su said she was hopeful the alert would prompt employers to collaborate with workers on better heat policies and also encourage workers to report violations.

The department plans to accelerate its enforcement of heat-safety violations in American workplaces and to perform more inspections in industries like construction and agriculture.

The Occupational Safety and Health Administration, or OSHA, which is part of the Labor Department, began developing new heat standards in 2022.

"We believe that a clear standard on heat is very, very important, given climate change. And given the realities that workers face, and that's why we're working on that process," Su said.

The new heat rule could take years to finalize and implement, experts have said. Congressional Democrats called for interim regulations on Thursday as a prolonged heat wave continues across the south.

Employees have a general duty to protect employees from known hazards, including heat. Su said OSHA has completed more than 2,600 investigations on heat in the workplace since April 2022.

"The dangers of extreme heat are not just for outdoor workers," Su said. "There's also indoor heat hazards. We see them in warehouses we see them for janitors who are cleaning in hot buildings, even the inside of airplanes can become over 100 degrees given the temperatures that we have right now."

The Southwest U.S. and southern Europe have experienced concurrent, historic heat waves this July that would have been “virtually impossible” if not for climate change, according to a recent attribution study led by scientists who study the probability of extreme weather events. A third heat wave in China would have been an extremely unlikely event if not for global warming, the group found. 

Extreme weather has made headlines all summer in the U.S. The country has endured a summer of smoke from record-setting Canadian wildfires, flood-causing bouts of extreme precipitation in the Northeast and hot tub temperatures along the Florida coastline.

“The extreme weather which has affected many millions of people in July is unfortunately the harsh reality of climate change and a foretaste of the future,” World Meteorological Organization Secretary-General Petteri Taalas said in a news release.

CORRECTION (July 27, 2023, 3:21 p.m. ET): A previous version of this article misstated the name of the group behind Thursday’s announcement. It is the World Meteorological Organization, not the World Meteorological Association.