It was expected, but now its certain: the Earths surface was warmer than ever recorded in 2024. According to the European climate service Copernicus, it was even 1.6°C hotter than the late 19th century. All datasets released today confirm the previous year as record warm.
Record heat
Where 2023 already stood out with its temperatures, 2024 has surpassed it by over 0.1°C. Image 1 illustrates the measured warming. The last decade holds the ten hottest years on record. The long-term warming is caused by greenhouse gas emissions, mainly from burning fossil fuels at a large scale. However, temperatures can vary significantly from year to year due to a mix of natural and human factors.
Remarkable
Despite the well-understood long-term warming, its striking that the last two years have been significantly warmer than prior years. Several factors have contributed to this rise in temperature over the last year and a half. For example, El Niño, which causes ocean surface waters to warm, played a role. Additionally, the amount of reflective aerosol (particulate matter) has decreased due to reduced sulfur emissions from China and shipping in recent years. This has diminished the cooling effect of this reflective sulfur. Consequently, the warming from greenhouse gases, previously masked by aerosol cooling, has become evident.
A recent study concluded that cloud cover over the ocean has decreased, leading to less reflection of sunlight and thus contributing to warming. However, researchers are still uncertain about the reasons behind this reduction in cloud cover. In coming years, further research will be done to better understand the warming peak of 2023-2024, especially because a crucial question arises: is the warming accelerating? Satellite observations of the Earths radiation balance seem to indicate so.