10 Cities Report 2021 as Hottest Year on Record; U.S. Sees Warmest December in History

The United States saw abnormally high temperatures and extreme weather events in 2021 as the nation experienced its warmest December in history and several cities reported last year as their hottest year yet.

Three different reports were released on Monday saying the U.S. is struggling with global warming and 2021 showed the effects of what's to come.

Last year was the fourth warmest year on record with an average temperature of 54.5 degrees, according to a report from the National Oceanic and Atmospheric Administration (NOAA). The United States also recorded the hottest December on record with an average temperature of 39.3 degrees, 6.7 degrees higher than average.

The warmer weather has been noticeable across the country as several cities reported 2021 as their hottest year on record. The 10 cities include Toledo, Ohio; Sault Ste. Marie, Michigan; Montpelier, Vermont; Milwaukee, Wisconsin, Erie, Pennsylvania; Buffalo, New York; Boston, Massachusetts; Bismarck, North Dakota; Baltimore, Maryland; and Akron, Ohio.

The country also saw a series of bizarre weather disasters last year. Portland reported temperatures reaching 116 degrees after an extreme heatwave hit the Pacific Northwest.

Texas reported deadly ice storms; the Midwest reported tornados for the first time in December; four hurricanes caused extensive damage; wildfires swept across part of the country; a derecho was reported; as well as extensive flooding, mudslides and droughts.

"It was a tough year. Climate change has taken a shotgun approach to hazards across the country," said Adam Smith a climatologist and economist for NOAA.

Hottest Year Ever For Some U.S. Cities
Last year was the fourth warmest year on record in the United States, according to a report from the National Oceanic and Atmospheric Administration. The U.S. also recorded the hottest December on record. The country endured a series of bizarre weather disasters as well. Above, a kayaker paddles in Lake Oroville as water levels remained low due to continuing droughts in Oroville, California, on Aug. 22, 2021. Ethan Swope/AP Photo

A report from the Rhodium Group, an independent research firm, on Monday said that in 2021, America's emissions of heat-trapping gas rebounded from the first year of the pandemic at a faster rate than the economy as a whole, making it harder to reach the country's pledge to the world to cut emissions in half compared to 2005 by 2030. And last year was the deadliest weather year for the contiguous United States since 2011, with 688 people dying in 20 different billion-dollar weather and climate disasters combining to cost at least $145 billion, the NOAA said Monday.

That was the second highest number of billion-dollar weather disasters — which are adjusted for inflation with records going back to 1980— and third costliest.

Scientists have long said human-caused climate change makes extreme weather nastier and more frequent, documenting numerous links to wild and deadly weather events. They say hotter air and oceans and melting sea ice alter the jet stream, which brings and stalls storm fronts, makes hurricanes wetter and stronger, and worsens western droughts and wildfires.

While 2020 set the record for the most billion-dollar disasters, in 2021, "the extremes seemed a bit more profound than in 2020," Smith said.

Last year, billion-dollar weather disasters were more than twice as deadly as in 2020, when those extremes killed 262 people. The last deadlier year was 2011. Hurricane Maria in 2017 killed nearly 3,000 people in Puerto Rico, which isn't part of the contiguous United States.

Changes in where people live and housing vulnerability were factors, Smith said, "but the 800-pound gorilla in the room is, of course, climate change, because that's accelerating all of these trends in regards to disaster potential for damage."

"We're having these compound cascading events one after another, after another," Smith said. "A lot of trends are going in the wrong direction."

The last five years have cost $742 billion in 86 separate billion-dollar weather disasters, an average of more than 17 a year, a new record. That's nearly $100 billion more than the combined total of all the billion-dollar disasters from 1980 to 2004, adjusted for inflation and far more the three billion-dollar disasters a year that the nation averaged in the 1980s.

"That's exactly what I'd expect with climate change because climate change is essentially supercharging many types of extreme weather, making heatwaves, droughts, wildfires, intense rainfall, flooding and storms more severe, destructive and deadly," said Jonathan Overpeck, dean of environmental studies at the University of Michigan, who wasn't part of the reports.

National temperature records go back 127 years and the 20th century average is 52 degrees.

Experts expected U.S. greenhouse emissions to increase from the steep 2020 pandemic dive, but the scope of the jumped worried them.

"What was dismaying was that emissions bounced back even faster than the economy as a whole," said Rhodium Group partner Kate Larsen, a co-author of the emissions report, which was based on daily and weekly government data.

Coal use increased for the first time since 2014, 17% from 2020, mostly because of spikes in natural gas prices, Larsen said.

"This is an example of how we've been riding on cheap natural gas to drive coal's decline over the last 15 years," Larsen said.

The other major factor was transportation emissions, mostly from long-haul diesel trucking, rising 10 percent, as freight nearly returned to pre-pandemic levels and is likely to continue to rise, Larsen said.

Over the long run, U.S. greenhouse gas emissions have been decreasing — even with 2021's jump from the sudden 2020 plunge. However, last year's emissions increases the difficulty in reaching the goal President Joe Biden set as part of the Paris and Glasgow climate agreements, Larsen said. She said to get to the 50 percent cut Biden pledged, the country needs to be reducing emissions 5 percent a year, not increasing.

"We are running out of time," she said.

Cornell University climate scientist Natalie Mahowald, who wasn't part of the reports, agreed.

"The radical changes in our economy that are required for reaching low climate goals have not been achieved," Mahowald said. "Unfortunately, what we are seeing today is just the tip of the iceberg in terms of what we will see unless substantial reductions in emissions are made and quickly."

The Associated Press contributed to this report.