Global temperatures in 2021 were the sixth warmest on record, while the United States experienced its fourth warmest year and suffered 20 severe natural disasters that inflicted damage costing more than $ 145 billion, according to the United States National Oceanic and Atmospheric Administration (NOAA).
Even though 2021 temperatures were slightly cooler than the previous two years, the western United States was still devastated by a number of wildfires that caused damage costing more than $10 billion.
Other severe weather events include the winter storm in Texas in February, which caused $24 billion in damage, and Hurricane Ida in late August, which caused destruction costing $75 billion.
“Unfortunately, we expect to see more of these extremes in a warmer world,” said Russell Vose, head of climate monitoring for NOAA. “And some of those events have been much aggravated by global warming, like the heat wave in the Pacific Northwest.”
For other events, such as the Texas freeze, the role of climate was less clear, Vose added.
The past seven years have been the warmest on record, reflecting the impact of global warming caused by rising greenhouse gas emissions.
In 2022, global temperatures were very likely to be among the 10 hottest on record, Vose said. “This is all due to the increase in heat-trapping gases like carbon dioxide.”
Two factors have contributed to making 2021 slightly cooler than the previous two years: the La Niña weather pattern across the Pacific as well as the resumption of economic activity which is causing aerosols in the atmosphere.
Aerosols, which are small particles suspended in the atmosphere, can have a cooling effect because they reflect some of the sunlight.
“In 2020, we estimated that the closures had slightly raised the temperature of the planet, due to the removal of nitrates and other aerosols,” said Gavin Schmidt, director of the Goddard Institute for Space Studies at NASA. “So 2021 would have been a relatively cool year, even without La Niña.”
A similar NASA study, also published this week, found 2021 tied with 2018 for the world’s sixth hottest year, due to a different benchmark and methodology.
The NASA and NOAA temperature analysis closely followed a similar analysis from other institutions, including Europe’s Copernicus group, which calculated 2021 to be the fifth hottest on record.
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