US records hottest summer since the Dust Bowl, NOAA says

The United States has recorded its hottest summer on record this year narrowly surpassing the previous record set in 1936 during the Dust Bowl, according to a recent report from the National Oceanic and Atmospheric Administration (NOAA).

"Summer 2021 neck and neck with 1936 Dust Bowl summer for hottest on record in the U.S. Multiple deadly weather and climate disasters also struck the nation in August," the NOAA tweeted on Thursday. 

According to the NOAA, the average temperature this summer for the contiguous U.S. was 74 degrees Fahrenheit which NOAA says is 2.6 degrees above average. 

This beats the previous record set in 1936 by less than 0.01 degrees warmer than during the Dust Bowl, a period of severe drought impacting much of the American West. 

"Sixteen additional states had a top-five warmest summer on record. No state ranked below average for the summer season," NOAA officials wrote in its climate report.

RELATED: Pacific Northwest heat wave likely killed ‘billions’ of marine animals, experts say

The report follows news from U.S. weather officials who announced that July 2021 became the hottest month in 142 years of recordkeeping. 

As extreme heat waves struck parts of the U.S. and Europe, the globe averaged 62.07 degrees (16.73 degrees Celsius) last month, beating out the previous record set in July 2016 and tied again in 2019 and 2020, the NOAA said Friday. The margin was just .02 degrees (.01 Celsius),

The deadly heat wave had a particularly devastating impact on the Pacific Northwest likely resulting in the death of more than 1 billion marine animals, according to researchers analyzing the impacts of climate change on the area. 

While the official death toll on marine animals is still being tallied, Christopher Harley, a marine biologist at the University of British Columbia, says the numbers could be in the billions.

"I know that it’s a huge number, it’s hard to get your head around and people are skeptical about the number that is that big, and they should be, but you can fit 50 mussels into the palm of your hand because they’re not very big and you can fit a few thousand onto a stovetop," Harley said. 

The last seven Julys, from 2015 to 2021, have been the hottest seven Julys on record, said NOAA climatologist Ahira Sanchez-Lugo. June was 1.67 degrees (0.93 degrees Celsius) warmer than the 20th century average for the month.

"This is climate change," said Pennsylvania State University climate scientist Michael Mann. "It is an exclamation mark on a summer of unprecedented heat, drought, wildfires and flooding."

In July, a prestigious United Nations science panel warned of worsening climate change caused by the burning of coal, oil and natural gas and other human activity.

RELATED: Pacific Northwest heat wave may have killed hundreds, officials say

Warming on land in western North America and in parts of Europe and Asia really drove the record-setting heat, said NOAA climatologist Ahira Sanchez-Lugo. While the worldwide temperature was barely higher than the record, what shattered it was land temperature over the Northern Hemisphere, she said.

Northern Hemisphere temperatures were a third of a degree (.19 degrees Celsius) higher than the previous record set in July 2012, which for temperature records is "a wide margin," Sanchez-Lugo said.

July is the hottest month of the year for the globe, so this is also the hottest month on record.

One factor helping the world bake this summer is a natural weather cycle called the Arctic Oscillation, sort of a cousin to El Nino, which in its positive phase is associated with more warming, the NOAA climatologist said.

While the world set a record in July, the U.S. only tied for its 13th hottest July on record. Even though California, Nevada, Oregon and Washington had their hottest Julys, slightly cooler than normal months in Texas, Oklahoma, Kansas, Arkansas, Missouri, Alabama, Maine, Vermont and New Hampshire kept the nation from approaching record heat levels.

The last time the globe had a July cooler than the 20th century average was in 1976, which was also the last year the globe was cooler than normal.

"So if you’re younger than 45 you haven’t seen a year (or July) where the mean temperature of the planet was cooler than the 20th century average," said Princeton University climate scientist Gabriel Vecchi.