2025 is expected to rank as the third-hottest year ever recorded, reflecting an alarming trend in global temperature rise. Recent data and studies shed light on the causes and implications of this unprecedented heat. A peer-reviewed paper released in December 2023 highlighted the role of low-lying clouds in allowing more heat to reach the Earth's surface, further contributing to the warming trend.
Natural climate patterns such as El Niño typically influence global temperatures, but they cannot solely account for the current temperature surge. Notably, a shift in 2020 to cleaner shipping fuels, which reduced sulfur emissions, may have inadvertently accelerated warming by diminishing the cooling effect these emissions previously provided. In January 2024, the Copernicus Climate Change Service reported the warmest January on record, with surface-air temperatures 1.75°C above preindustrial levels.
The Arctic region is also experiencing dramatic changes, with sea ice hitting a record low in January 2024. This period is likely the warmest Earth has been in 125,000 years. Furthermore, global temperatures averaged across 2023 and 2024 exceeded 1.5°C above preindustrial levels for the first time, testing but not permanently breaching the Paris climate accord's target.
Climate scientists attribute long-term global heating primarily to the burning of fossil fuels. While natural climate variability can cause temperature fluctuations from year to year, it is insufficient to explain the persistent upward trend. Even La Niña, which is expected to be weak in 2024, has not provided the anticipated cooling effect. The equatorial Pacific Ocean shows signs of a slowing or stalling of its move towards cooling, further complicating climate predictions.
Julien Nicolas, a climate scientist at Copernicus, expressed his surprise at the current climate conditions.
“This is what makes it a bit of a surprise: you’re not seeing this cooling effect, or temporary brake at least, on the global temperature that we were expecting to see.” – Julien Nicolas, a climate scientist at Copernicus
January 2024 marked the 18th out of the past 19 months with global-average surface temperatures above the 1.5°C preindustrial level. This trend raises questions about why temperatures remain so high despite expectations.
“That is the thing that is a little puzzling – why they remain so warm,” – Julien Nicolas, a climate scientist at Copernicus
The scientific community continues to debate these findings, acknowledging that many factors contribute to climate dynamics.
“It’s really still a matter of debate,” – Julien Nicolas, a climate scientist at Copernicus