According to the US National Oceanic and Atmospheric Administration(NOAA), the global temperatures in 2021 were sixth-warmest since records began. However, the US had its fourth-warmest decade and experienced 20 severe natural catastrophes that cost more than $145bn.
Despite 2021 temperatures being slightly cooler than in the previous two decades, the western US was still devastated from a series of wildfires that caused more than $10bn in damage.
Other severe weather events were the Texas winterstorm in February, which caused $24bn worth of damage, and Hurricane Ida in August, which caused destruction that cost $75bn.
“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 these events were made much worse by global warming, such as the heatwave in the Pacific Northwest.”
Vose said that climate played a less important role in other events, such Texas’ deep freeze.
The impact of global warming and rising greenhouse gas emissions has led to the highest temperatures in seven years.
Vose said that in 2022, global temperatures will be among the 10 warmest ever recorded. “All of this is driven by increases in heat-trapping gases like carbon dioxide.”
Two factors contributed to 2021 being slightly cooler than the previous year: La NiñaWeather patterns across the Pacific and the resumption economic activity that creates aerosols in atmosphere.
Aerosols, small particles suspended in the air, can cool off by reflecting back some sunlight.
“In 2020, we estimated that lockdowns had increased the temperature of the planet slightly, due to the clearing out of nitrates and other aerosols,” said Gavin Schmidt, director of Nasa’s Goddard Institute for Space Studies. “So 2021 would have been a relatively cool year, even without La Niña.”
A similar report from Nasa was also released this week. It found 2021 tied with 2018 as the sixth-warmest year globally due to a new baseline and methodology.
The temperature analysis from Nasa and NOAA closely tracked similar analysis from other institutions, including Europe’s Copernicus group, which calculated that 2021 was the fifth-warmestRecord.