2024 Record Global Warming

Sources: BBC , NASA , United Nations , WMO , NOAA , CNN , Ars Technica , The Hill and The Weather Channel

United Nations weather experts from the World Meteorological Organization (WMO) confirmed on 10 January 2025 that 2024 was the hottest year on record, at 1.55 degrees Celsius (C) above pre-industrial temperatures (1850-1900 average). It was the second year in a row the planet set a yearly warm temperature record. The past ten years 2015-2024 are the ten warmest years on record.

The datasets used by WMO are from:

  1. the European Center for Medium Range Weather Forecasts (ECMWF - Copernicus - ERA5),
  2. the Japan Meteorological Agency (JRA-3Q),
  3. the National Aeronautics and Space Administration (NASA - GISTEMP),
  4. the US National Oceanic and Atmospheric Administration (NOAA - NOAA_v6),
  5. the UK Met Office in collaboration with the Climatic Research Unit at the University of East Anglia (HadCRUT5) and
  6. Berkeley Earth (Berkely_Earth).

Four of the six international datasets crunched by WMO indicated a higher than 1.5°C global average increase for the whole of last year, marking the first time that the Paris Agreement goal of limiting warming to 1.5°C has been exceeded. Two of the organizations, the European Union's Copernicus and Berkeley Earth, place the year at about 1.6°C above pre-industrial temperatures (1850-1900 average). NASA and NOAA both place the mark at slightly below 1.5°C over pre-industrial temperatures. However, the NASA and NOAA differences largely reflect the uncertainties in measuring temperatures during that period rather than disagreement over 2024.

In 2024, the world saw blistering temperatures in west Africa, prolonged drought in parts of South America, intense rainfall in central Europe and some particularly strong tropical storms hitting north America and south Asia. These events were just some of those made more intense by climate change over the last year, according to the World Weather Attribution group.

The average annual temperature across the contiguous U.S. was 55.5°F - 3.5° above the 20th-century average - ranking as the nation's warmest year in NOAA's 130-year climate record. Seventeen states - Indiana, Kentucky, Maine, Maryland, Michigan, Minnesota, New Hampshire, New York, Ohio, Oklahoma, Pennsylvania, Tennessee, Texas, Vermont, Virginia, West Virginia and Wisconsin - had their warmest year on record.

Image produced by Climate Central.

Temp Precip

The 1.5°C marker is significant because it was a key goal of the 2015 Paris Agreement to try to ensure that global temperature change does not rise more than this above pre-industrial levels, while striving to hold the overall increase to well below 2°C. Scientists are much more concerned about breaches over decades, rather than single years - as above that threshold humans and ecosystems may struggle to adapt - but 2024's record "does mean we're getting dangerously close," said Joeri Rogelj, a climate professor at Imperial College London. While these markers are based on a 20-year average, not a single year, the trend is worrisome.

One reason scientists are urging the global community to try to limit warming is to avoid crossing "tipping points" - extreme environmental damage caused by climate change that is difficult to reverse. This includes the potential for the Greenland ice sheet to melt, the Amazon rainforest to decline significantly and the collapse of Atlantic Ocean currents that help regulate global temperature.

Alex Ruane, co-director of the climate impacts group at NASA's Goddard Institute for Space Studies, pointed out that in general, the years have been getting warmer, not cooler. "We keep having 10-year periods that are much warmer than the previous 10-year periods. So we don't really see a lot of room for temperature to come back down unless policies change," said Ruane, who is also a research scientist at Columbia University and has worked on the United Nations's latest climate report.

A separate study published in Advances in Atmospheric Sciences found that ocean warming in 2024 played a key role in the record high temperatures. About 90% of the excess heat from global warming is stored in the ocean, making ocean heat content a critical indicator of climate change. The ocean is the warmest it has ever been as recorded by humans, not only at the surface but also for the upper 2000 meters, according to the study led by Prof. Lijing Cheng with the Institute of Atmospheric Physics at the Chinese Academy of Sciences. It involved a team of 54 scientists from seven countries and 31 institutes. Sea Surface Temperature Anomalies for the North Atlantic are available on this website at this LINK.