If we line up the baselines, we can see that these various services are roughly in agreement, but most of the differences are due to uncertainty in the measurements, with the rest just being how they handle things like areas with sparse data. This is due to different factors.
But even the details of 2024 don’t capture exactly how exceptional the warmth of the past two years has been. Since about 1970, greenhouse gas emissions have caused temperatures to rise almost linearly, even though many individual years have been warmer or colder than trend. The past two years have been extreme outliers from this trend. The last time there was a single year comparable to 2024 was in the 1940s. The last time there were two consecutive years like this was in 1878.
“These were during the ‘Great Drought’ of 1875-1878, which is estimated to have killed around 50 million people in India, China, parts of Africa and South America,” the EU’s Copernicus Service said. It is written down. Despite many climate disasters, the world avoided a similar experience at least until 2023-2024.
Berkeley Earth offers a slightly different way to compare each year since 1970 to the amount of warming expected from cumulative greenhouse gas emissions.
Compared to the expected warming caused by greenhouse gases, 2024 will be a significant deviation.
Credit: Berkeley Earth
These show that warming closely matches expectations over a 50-year period, taking into account year-to-year variations in the climate system. 2023 and 2024 mark the end of a decade in which most years were above the trend line, but mark a dramatic departure from that trajectory. Berkeley Earth estimates that the chance of such a thing happening is only 1 in 100, due to internal changes in the climate.
Is this a new trend?
The big question is whether 2024 is an anomaly and should we expect a return to the trends that have prevailed since the 1970s, or whether it marks a departure from recent climate trends. And we don’t have a big answer to that either.
