Heat record despite La Niña: is global warming accelerating?
It's all over the media today: January 2025 was the warmest January ever recorded worldwide and was 1.75 °C above pre-industrial levels. And this despite the normally cooling effect of La Niña. It was the 18th month with over 1.5 °C above pre-industrial levels and thus also above the 1.5 °C target of the Paris Agreement. Climate researchers are discussing the possibility that global warming has accelerated and that we will reach a point sooner than previously thought where processes are set in motion that can no longer be reversed.
Global temperatures for January 2025
- January 2025 was the warmest January worldwide with an average ERA5 surface temperature of 13.23°C, 0.79°C above the January average from 1991-2020.
- January 2025 was 1.75 °C above pre-industrial levels and was the 18th month in the last 19 months in which the global average surface air temperature was more than 1.5 °C above pre-industrial levels.
- The last 12-month period (February 2024 - January 2025) was 0.73°C above the 1991-2020 average and 1.61°C above the estimated 1850-1900 average used to define the pre-industrial level.
Monthly anomalies of global surface air temperature (°C) compared to 1850-1900 from January 1940 to January 2025, plotted as time series for each year. The year 2025 is shown with a thick red line, the year 2024 with a thick orange line, the year 2023 with a thick yellow line and all other years with thin gray lines. Data source: ERA5. Credit: Copernicus Climate Change Service /ECMWF.
Hydrological features of January 2025
- In January 2025, it was mostly wetter than average in the Western European regions and in parts of Italy, Scandinavia and the Baltic states; heavy rainfall led to flooding in some regions.
- Conversely, the north of the United Kingdom and Ireland, eastern Spain and north of the Black Sea experienced above-average dry weather.
- Outside Europe, it was wetter than average in Alaska, Canada, central and eastern Russia, eastern Australia, south-east Africa and southern Brazil, with flooding and associated damage occurring in some regions.
- The southwest of the United States and northern Mexico, North Africa, the Middle East, Central Asia and eastern China as well as large parts of southern Africa, southern South America and Australia experienced above-average drought conditions.
This was announced by the Climate Change Service of the EU Copernicus program in a press release on 6 February.
Lack of cooling due to La Niña particularly surprising
The extreme January value surprised the experts because we are currently in a phase of the La Niña weather phenomenon. This is the cooler flip side of El Niño, which is normally associated with lower global temperatures. "January 2025 is another surprising month, continuing the record temperatures observed over the past two years, despite the development of La Niña conditions in the tropical Pacific and their temporary cooling effect on global temperatures," explained Samantha Burgess from the European Centre for Medium-Range Weather Forecasts (ECMWF).
"Unfortunately, we have turned back the planet's geological clock in terms of global average temperatures by as much as 125,000 years in just one generation," says expert Diana Ürge-Vorsatz, Professor of Environmental Sciences at the Central European University (CEU) and Vice Chair of the Intergovernmental Panel on Climate Change (IPCC), according to STANDARD.
We need to stay as far below 2 degrees as possible
"What is really amazing is the huge difference between the temperatures of the last 13 months and the previous records. We are now in truly uncharted territory and the more the climate warms, the more records will be broken in the coming months and years," explains Carlo Buontempo, Director of Copernicus.
To date, models have assumed that we will permanently exceed the 1.5 °C mark in less than ten years. The rapid rise to 1.61 °C in the last 12 months has led many climate researchers to doubt these models. "But it could happen sooner, because experts are debating whether warming is accelerating," says physicist Ürge-Vorsatz, and the strategic head of climate at ECMWF, Burgess, takes a similar view: "We are now on the verge of exceeding the limit of 1.5 degrees Celsius set out in the Paris Agreement, and the average of the last two years is already above this value," explains the researcher. In her view, only the goal of staying as far below two degrees as possible is still achievable.
A new study by former leading NASA scientist James Hansen and other researchers also assumes that global warming is accelerating. The result of this publication has led to heated debate and is dividing the research community.
"The persistence of record warmth through 2023, 2024 and now into the first month of 2025 is staggering, to say the least," said Jonathan Overpeck, environmental dean at the University of Michigan, who was not involved in the Hansen study. "There is little doubt that global warming and the effects of climate change are accelerating." However, not all climate researchers share this view.
"If there is a possibility that global warming will accelerate, we should do our best to prevent it."
Diana Ürge-Vorsatz, Vice Chair of the Intergovernmental Panel on Climate Change (IPCC)
Every tenth of a degree counts
From the point of view of climate researchers, it is important to keep the rise in temperature as low as possible, "because every tenth of a degree makes a big difference," says the physicist, who has a degree in physics, adding that when we reach the tipping points defined by research, we set processes in motion that have irreversible consequences for us humans.
"The earth is becoming more dangerous for everyone. Extreme heat is the new abnormal. As long as the world continues to burn fossil fuels at a high rate, the earth will get hotter and hotter"
UN Secretary Antonio Guterres
Costs of climate change significantly higher than investments in transformation
Andreas Fink from the Karlsruhe Institute of Technology emphasizes that "the costs of escalating climate change will be significantly higher than the transformation to a decarbonized economy," says the meteorologist. "Not to mention the consequences of potential mass migrations from tropical regions, which will fall out of the so-called climate niche due to global warming. In other words, life here will simply become unbearable due to the hot and humid climate." For this reason, we must make a concerted effort to radically reduce greenhouse gas emissions and stay as far below 2 degrees as possible.
Phenomena such as extreme heat and drought, increased and more intense fires such as in Los Angeles, heavy rainfall and associated flooding such as in Spain, more severe and more frequent hurricanes - all of these are caused by climate change, with unforeseeable consequences for humanity.
"Extreme temperatures are no longer a phenomenon limited to one day, one week or one month. What unites our divided world is that we are all increasingly feeling the heat. The planet is becoming more dangerous for everyone," said UN Secretary Antonio Guterres, a staunch critic of the oil, coal and gas industry, leaving no doubt as to the cause: "We know what's driving it: fossil-fueled, man-made climate change. And we know it's getting worse," he continued.
"Tackling the symptoms of the climate crisis is important, but to tackle the problem we need to protect our only home from the destruction caused by fossil fuels. The disease is inaction on climate action."
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