Global temperatures, greenhouse gases hit record highs in 2023: report

National Oceanic and Atmospheric Administration – Greenhouse gas concentrations, the global temperature across land and oceans, global sea level and ocean heat content all reached record highs in 2023, according to the 34th annual State of the Climate report.

The international annual review of the world’s climate, led by scientists from NOAA’s National Centers for Environmental Information and published by the Bulletin of the American Meteorological Society (BAMS), is based on contributions from more than 590 scientists in nearly 60 countries.

Carbon dioxide (CO2), methane and nitrous oxide⁠—Earth’s major atmospheric greenhouse gases⁠—once again reached record high concentrations in 2023. Annual growth in global mean CO2 has increased from 0.6±0.1 parts per million (ppm) yr−1 in the early 1960s to an average of 2.5 ppm yr−1 during the last decade of 2014 to 2023. The growth from 2022 to 2023 was 2.8 ppm, the fourth highest in the record since the 1960s.

A range of scientific analyses indicate that the annual global surface temperature was 0.55 to 0.60 of a degree C above the 1991 to 2020 average. This makes 2023 the warmest year since records began in the mid to late 1800s, surpassing the previous record of 2016 by 0.13 to 0.17 C. The transition in the Pacific Ocean from La Niña at the beginning of the year to a strong El Niño by the end of the year contributed to the record warmth. All seven major global temperature datasets used for analysis in the report agree that the last nine years (2015 to 2023) were the nine warmest on record. The annual global mean surface temperature has increased at an average rate of 0.08 to 0.09 C per decade since 1880, and at a rate more than twice as high since 1981.

El Niño conditions in the equatorial Pacific Ocean emerged in boreal spring 2023 and strengthened throughout the year. The mean annual global sea-surface temperature in 2023 was record high, surpassing the previous record of 2016 by 0.13 C. Each month from June to December was record warm. On Aug. 22, an all-time high globally averaged daily sea-surface temperature of 18.99 C was recorded.

During late spring and a record-warm summer, approximately 37 million acres burned across Canada, an area more than twice the size of Ireland and more than double the previous record from 1989. Approximately 232,000 people were evacuated due to the threat of wildfires, and smoke from the wildfires impacted regions across Canada and also affected the heavily populated cities of New York City and Chicago, and even areas of western Europe.

The Arctic had its fourth-warmest year in the 124-year record, with summer (July to September) record warm. Below-ground, permafrost temperatures were the highest on record at over half of the reporting sites across the Arctic. Permafrost thaw disrupts Arctic communities and infrastructure and can also affect the rate of greenhouse gas release to the atmosphere, potentially accelerating global warming. The seasonal Arctic minimum sea-ice extent, typically reached in September, was the fifth-smallest in the 45-year record. The amount of multiyear ice—ice that survives at least one summer melt season in the Arctic—continued to decline. Since 2012, the Arctic has been nearly devoid of ice that is more than four years old.

Both the Northern Sea Route and Northwest Passage became accessible to non-ice-hardened marine traffic. The Northern Sea Route, connecting the European Arctic to the Pacific Ocean via the north coast of Russia and Bering Strait, saw 75 ship transits in the 2023 open season, the second-highest number of ships on record. The Northwest Passage, which connects the Atlantic Ocean to the Pacific via northern Canada and Alaska waters, saw a record number of ship passages. A total of 42 ships made the complete Northwest Passage transit, far surpassing the previous record of 33 ships in 2017.

There were 82 named tropical storms during the Northern and Southern Hemisphere storm seasons last year, which was below the 1991–2020 average of 87. Seven tropical cyclones reached Category 5 intensity on the Saffir–Simpson Hurricane Wind Scale. Globally, the accumulated cyclone energy—a combined measure of the strength, frequency, and duration of tropical storms and hurricanes—rebounded from the lowest in the 43-year record in 2022 to above average in 2023.