It’s official. 2024 was the hottest year in the instrumental record. How hot? Last year the global average temperature rose more than 1.5 degrees Celsius (2.7 degrees Fahrenheit) above the 19th century pre-industrial mean, according to most of the scientific organizations that track global temperature trends. This exceeds, for the first time, the aspirational goal set forth by the 2015 Paris Climate Change Agreement to limit the increase in global temperatures to 1.5 degrees Celsius above pre-industrial levels. Each of the 10 hottest years have come over the past decade.
Let’s look at what various research groups have reported.
The European Copernicus Climate Change Service calculates that the 2024 global average temperature was 1.6 degrees Celsius (2.9 degrees Fahrenheit) above the pre-industrial average. That is 0.12 degrees Celsius higher than the previous highest annual value in 2023.
However, as the Copernicus report notes: “One or two years that exceed 1.5°C above the pre-industrial level does not imply that the Paris Agreement has been breached. However, with the current rate of warming at more than 0.2°C per decade, the probability of breaching the 1.5°C target of the Paris Agreement within the 2030s is highly likely.” This rate of temperature increase is about ten times faster than the increase that ended the last ice age about 11,500 years ago.
The independent Berkeley Earth group similarly reports that the “global annual average for 2024 in our dataset is estimated as 1.62 ± 0.06 °C (2.91 ± 0.11 °F) above the average during the period 1850 to 1900, which is traditionally used a reference for the pre-industrial period.” They add that 2024 was the warmest year on land, reaching 2.28 degrees Celsius, or 4.11 degrees Fahrenheit, above the 1850 to 1900 average. That is sharply up from the previous record set in 2023 by 0.20 degrees Celsius (0.35 degrees Fahrenheit).
The United Kingdom’s Met Office affirms that 2024 is the hottest year in their records. The U.K. climatologists estimate that global average temperature for 2024 was 1.53±0.08 degrees Celsius above the 1850–1900 global average.
The National Oceanic and Atmospheric Administration also reports that 2024 is the hottest year, but its estimate of global average temperature in 2024 at 1.46 degrees Celsius (2.63 degrees Fahrenheit) was slightly lower than the European and Berkeley Earth calculations.
Even according to the shorter-term satellite measurements by the University of Alabama, Huntsville climate researchers John Christy and Roy Spencer, “2024 was by far the warmest in the 46-year satellite record averaging 0.77 deg. C above the 30-year mean, while the 2nd warmest year (2023) was +0.43 deg. C above the 30-year mean.”
The increase coincided with a strong El Niño in which hotter ocean surface waters periodically sloshing across the Eastern Pacific Ocean raise average global temperatures. Some research suggests that a 2020 rule mandating that the world’s fleet of nearly 100,000 ocean-going freighters cut the amount of sulfur in their fuels by 80 percent is partially to blame for higher temperatures in the last few years. Sulfur particles served as nuclei for the creation of bright low-level clouds that reflect heat back into space. The absence of sulfur particles formerly emitted along ship tracks correlated with a reduction in the formation of cooling clouds. This reduction in air pollution suggests that the recent jump might be a one-time spike rather than an acceleration of a rising temperature trend.
The Copernicus report notes: “One or two years that exceed 1.5°C above the pre-industrial level does not imply that the Paris Agreement has been breached. However, with the current rate of warming at more than 0.2°C per decade, the probability of breaching the 1.5°C target of the Paris Agreement within the 2030s is highly likely.”
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