NASA and NOAA have officially declared 2023 as the hottest year on record, marking a concerning trend in global temperatures. The data presented by climate scientists indicates a consistent rise in temperatures, leading to extreme climate-driven weather events worldwide.
The analysis by NOAA and NASA utilized surface data that included sea surface temperatures from ships and buoys, as well as air temperatures from terrestrial weather stations, providing a comprehensive view of climate change.
NASA, NOAA Declares 2023 Hottest Year Since 1880
In a statement, NASA's Goddard Institute for Space Studies confirmed that 2023 was the hottest year on record, surpassing previous records dating back to 1880.
The analysis involves calculating annual global average temperatures and comparing temperature changes from 1951 to 1980. NASA said each month from June to December 2023 came in as the hottest month on record, with July ranking as the hottest month ever recorded.
Scientists examined the primary factors contributing to the unprecedented heat in 2023, focusing on the long-term increase in greenhouse gases. Human activities like burning fossil fuels for over a century have significantly elevated greenhouse gas levels in the atmosphere.
In May 2023, carbon dioxide concentrations peaked at 424 parts per million at NOAA's Mauna Loa Observatory in Hawaii, marking a steady increase since measurements began in 1958.
NASA noted that extending the record even further with ice cores, carbon dioxide concentrations are the highest they have been in at least 800,000 years.
Driven by Human-Induced Greenhouse Gases
Gavin Schmidt, director of NASA's Goddard Institute for Space Studies, noted that the warming trend over the past 50 to 60 years was primarily driven by "our changes to greenhouse gases, particularly carbon dioxide and methane."
The return of El Niño also contributed to the hot temperatures. El Niño, a natural climate variation, involves the weakening of trade winds and warmer sea surface temperatures in the tropical Pacific.
While the recent El Niño was not as strong as those in 2015-2016 or 1997-1998, both of which caused huge global average temperature spikes. Global ocean warming, the long-term warming trend from greenhouse gases, and the start of El Niño played a crucial role in creating a new record for heat.
"For the most part, it's us and El Niño... At the end of the day, humans are heating the planet, and El Niño is dancing on our heads," said Josh Willis, a climate scientist at NASA's Jet Propulsion Laboratory.
The entire tropical Pacific, North Atlantic, and other parts of the ocean experienced hotter-than-normal temperatures this year. According to NASA, the ocean absorbs around 90% of the heat trapped by rising greenhouse gases, leading to a continuous increase in ocean temperatures, eventually raising global temperatures.
Aerosols, which can impact climate by reflecting or absorbing sunlight, exhibited a global decreasing trend. Reductions in aerosols due to regulations aimed at improving air quality contribute to a slight warming effect. However, this effect is minor compared to the significant warming caused by rising greenhouse gases.
Scientists also investigated the impact of the Hunga Tonga-Hunga Ha'apai volcanic eruption in January 2022 on global temperatures. While the eruption released water vapor, a greenhouse gas, into the stratosphere and sulfate aerosols that can lead to cooling events, its overall impact on the record heat of 2023 was found to be limited.
"We are very interested in the weather and extremes of any particular year because those are the things that impact us," said Schmidt. "But the key difference between this decade and the ones before is that the temperatures keep rising because of our activities, principally the burning of fossil fuels."
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