2023 Sets Record as Hottest Year Ever

Long-Term Rise in Greenhouse Gases and Return of El Niño Identified as Key Drivers

2023 was the hottest year on record, with every month from June through December setting new records for heat, according to NASA's Goddard Institute for Space Studies.
The primary driver of the record heat was the long-term rise in greenhouse gases, particularly carbon dioxide and methane, resulting from human activities such as burning fossil fuels and changes in land use.
The return of El Niño in May 2023 contributed to the record heat, as it coincided with the long-term global warming trend and resulted in warmer sea surface temperatures in the tropical Pacific.
Global sea surface temperatures also set new records in 2023, with the North Atlantic and other parts of the ocean experiencing several marine heat waves.
Decreasing aerosols in the atmosphere due to regulations reducing air pollution and the eruption of the Hunga Tonga-Hunga Ha‘apai undersea volcano in January 2022 had minor effects on the record heat.