Earth's average surface temperature in 2023 was the warmest ever recorded, according to NASA analysis
Global temperatures in 2023 will be about 1.2 degrees Celsius above the average for the NASA reference period (1951-1980), according to scientists at NASA's Goddard Institute for Space Studies (GISS) in New York.
“The global temperature report from NASA and NOAA confirms what billions of people around the world experienced last year: We are facing a climate crisis,” said NASA Administrator Bill Nelson. “From extreme heat to wildfires to sea level rise, we can see our Earth changing. There is still much work to be done, but President Biden and communities across America are taking more steps than ever to reduce climate risks and help communities become more resilient, and NASA will continue to use our view of space to make important Bringing climate data to earth in a way that is understandable and accessible to all people. “NASA and the Biden-Harris Administration are working to protect our planet and its people for this generation and the next.”
In 2023, hundreds of millions of people around the world experienced extreme heat, with each month from June to December setting a world record for that month. July was the hottest month ever recorded. Overall, Earth was about 1.4 degrees Celsius warmer in 2023 than average at the end of the 19th century, when modern records began.
“The extraordinary warming we are experiencing is something we have never experienced in human history,” said Gavin Schmidt, director of GISS. “This is largely due to our fossil fuel emissions, and we are seeing the impacts in heatwaves, heavy rainfall and coastal flooding.”
Although scientists have conclusive evidence that the planet's long-term warming trend is being driven by human activity, they continue to study other phenomena that may influence annual or multiannual climate changes, such as El Niño, aerosols and pollution, and volcanic eruptions.
Typically, the largest source of interannual variability is the El Niño-Southern Oscillation oceanic climate pattern in the Pacific Ocean. This pattern consists of two phases – El Niño and La Niña – during which sea surface temperatures fluctuate between warmer, average and colder temperatures along the equator. Between 2020 and 2022, three consecutive La Niña events occurred in the Pacific Ocean, which tend to cause global temperatures to cool. In May 2023, the ocean transitioned from La Niña to El Niño, which typically coincides with the warmest years on record.
However, the record temperatures of the second half of 2023 occurred before the peak of the current El Niño phenomenon. Scientists expect El Niño's greatest impacts to occur in February, March and April.
Scientists have also been studying the possible effects of the January 2022 eruption of the underwater volcano Hunga Tonga-Hunga Ha'apai, which ejected water vapor and fine particles, or aerosols, into the stratosphere. A recent study found that volcanic aerosols, by reflecting sunlight away from Earth's surface, caused a slight overall cooling of less than 0.1 degrees Celsius in the Southern Hemisphere after the eruption.
“Even with occasional cooling factors like volcanoes or aerosols, we will continue to break records as long as greenhouse gas emissions continue to rise,” Schmidt said. “And unfortunately, we just broke another record for greenhouse gas emissions last year.”
“The record year of 2023 underscores the importance of taking urgent and continued action to combat climate change,” said NASA Deputy Administrator Pam Melroy. “Recent legislation committed the U.S. government’s largest climate investment, including billions to strengthen America’s resilience to the growing impacts of the climate crisis.” “As an agency focused on studying our changing climate, the fleet of Earth observation satellites “We continue to provide NASA with important data about our planet at scale to help everyone make informed decisions.”
Open science in action
NASA creates its temperature records from surface air temperature data collected at tens of thousands of weather stations, as well as sea surface temperature data collected from ship- and buoy-based instruments. This data is analyzed using methods that take into account the varying distances of temperature stations around the world and the effects of urban warming, which could distort the calculations.
Independent analyzes by NOAA and the Hadley Center (part of the UK Met Office) concluded that the planet's surface temperatures in 2023 were the highest since modern records began. These scientists use much of the same temperature data in their analyses, but use different methods. Although the classifications may differ slightly between records, they are broadly consistent and show the same sustained long-term warming over the past few decades.
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NASA analysis confirms 2023 is the warmest year on record