Global temperatures in the first quarter of 2025 were the second warmest on record, extending a remarkable run of exceptional warmth that began in July 2023.
This is despite weak La Niña conditions during the first two months of the year – which typically result in cooler temperatures.
With temperature data for the first three months of the year now available, Carbon Brief finds that 2025 is very likely to be one of the three warmest years on record.
However, it currently remains unlikely that temperatures in 2025 will set a new annual record.
In addition to near-record warmth, the start of 2025 has seen record-low sea ice cover in the Arctic between January and March – and the second-lowest minimum sea ice extent on record for Antarctica.
Second-warmest start to the year
In this quarterly state of the climate assessment, Carbon Brief analyses records from five different research groups that report global surface temperature records: NASA, NOAA, Met Office Hadley Centre/UEA, Berkeley Earth and Copernicus/ECMWF.
The figure below shows the annual temperatures from each of these groups since 1970, along with the average over the first three months of 2025.
(It is worth noting that the first three months may not be representative of the year as a whole, as greater historical warming rates mean that temperatures relative to pre-industrial levels tend to be larger in the northern hemispheric winter months of December, January and February.)
Annual global average surface temperatures from NASA GISTEMP, NOAA GlobalTemp, Hadley/UEA HadCRUT5, Berkeley Earth and Copernicus/ECMWF (lines), along with 2025 temperatures so far (January-March, coloured dots). Anomalies plotted with respect to the 1981-2010 period, and shown relative to pre-industrial based on the average pre-industrial temperatures in the Hadley/UEA, NOAA and Berkeley datasets that extend back to 1850. Chart by Carbon Brief.
Starting with this state of the climate update, Carbon Brief will be showing a World Meteorological Organization (WMO) aggregate of the five surface temperature records, rather than highlighting any particular one, reflecting a single best-estimate across the different groups.
The WMO aggregate is calculated by averaging the different records using a common 1981-2010 baseline period, before adding in the average warming since the pre-industrial period (1850-1900) across the datasets – NOAA, Hadley, and Berkeley – that extend back to 1850.
The figure below shows how global temperature so far in 2025 (black line) compares to each month in different years since 1940 (with lines coloured by the decade in which they occurred) in the WMO aggregate of surface temperature dataset.
Temperatures for each month from 1940 to 2025 from the WMO aggregate of temperature records. Anomalies plotted with respect to a 1850-1900 baseline. Chart by Carbon Brief.
The first three months of 2025 have been unusually warm, coming in in the top-three warmest on record across all the different scientific groups that report on global surface temperatures. This is despite the presence of moderate La Niña conditions in the tropical Pacific, which typically suppress global temperatures.
January 2025 was the warmest January on record in the WMO aggregate, February was the third warmest and March was tied with 2016 as the second warmest.
When combined, the first three months of the year in 2025 were the second-warmest Q1 period in the historical record, just 0.035C below the record set in 2024 after the peak of a strong El Niño event, as shown in the figure below.
Q1 temperature anomalies from 1850 through 2025 from the WMO aggregate of temperature records. Anomalies plotted with respect to a 1850-1900 baseline. Chart by Carbon Brief.
The persistence of warmth after the end of the 2023-24 El Niño event – and through a weak La Niña – has been highly unusual by historical standards. In most prior cases, global temperatures returned closer to the long-term temperature trend following the return to neutral El Niño Southern Oscillation (ENSO) conditions in the tropical Pacific.
Weak La Niña conditions have faded over the past month, with ENSO-neutral conditions returning and expected to persist for most models through the remainder of the year. However, predictions of ENSO status are particularly uncertain at this time of year due to a phenomenon known as the “spring predictability barrier”.
The figure below shows a range of different forecast models for the ENSO for the rest of this year, produced by different scientific groups. The values shown are sea surface temperature variations in the tropical Pacific – known as the El Niño 3.4 region – for overlapping three-month periods.
ENSO forecast models for overlapping three-month periods in the Niño3.4 region (January, February, March – JFM – and so on) for the remainder of 2025. Credit: Image provided by the International Research Institute for Climate and Society at Columbia Climate School.
On track to be a top-three warmest year
By looking at the relationship between the first three months and the annual temperatures for every year since 1970 – as well as ENSO conditions for the first three months of the year and the projected development of El Niño conditions for the remaining nine months – Carbon Brief has created a projection of what the final global average temperature for 2025 will likely be.
The analysis includes the estimated uncertainty in 2025 outcomes, given that temperatures from only the first quarter of the year are available so far.
The chart below shows the expected range of 2025 temperatures using the WMO aggregate – including a best-estimate (red) and year-to-date value (yellow). Temperatures are shown with respect to the pre-industrial baseline period (1850-1900).
Annual global average surface temperature anomalies from the WMO aggregate plotted with respect to a 1850-1900 baseline. To-date 2025 values include January-March. The estimated 2025 annual value is based on the relationship between the January-March temperatures and annual temperatures between 1970 and 2024. Chart by Carbon Brief.
Carbon Brief’s projection suggests that 2025 is virtually certain to be one of the top-three warmest years, with a best-estimate approximately equal to global temperatures in 2023.
However, this model assumes that 2025 follows the type of climate patterns seen in the past – patterns that were notably broken in 2023 – and to a lesser extent in 2024. Other recent estimates – such as one published by Berkeley Earth – give a higher probability of around 34% that 2025 will set a new temperature record.
The figure below shows Carbon Brief’s estimate of 2025 temperatures using the WMO aggregate, both at the beginning of the year and once each month’s data has come in. The estimate jumped notably after t2025 saw the warmest January on record, but has been relatively stable over the past three months.
Record-low Antarctic and Arctic sea ice
Both Arctic and Antarctic sea ice extent spent much of early 2025 at record, or near-record, lows.
The figure below shows both Arctic and Antarctic sea ice extent in 2025 (solid red and blue lines), the historical range in the record between 1979 and 2010 (shaded areas) and the record lows (dotted black line).
(Unlike global temperature records, which only report monthly averages, sea ice data is collected and updated on a daily basis, allowing sea ice extent to be viewed up to the present.)
Arctic and Antarctic daily sea ice extent from the US National Snow and Ice Data Center (NSIDC). The bold lines show daily 2025 values, the shaded area indicates the two standard deviation range in historical values between 1979 and 2010. The dotted black lines show the record lows for each pole. Chart by Carbon Brief.
Arctic sea ice saw a new record low nearly each day between January and March, recording a record-low winter peak extent in late March. Ice extent subsequently moved out of record-low territory in April.
It is worth noting that, as northern hemisphere winter conditions remain cold enough to refreeze sea ice, there tends to be less variability in extent year-to-year in the winter than in the summer, as the chart below illustrates.
Antarctic sea ice started the year within the historical range (1979-2010), before plunging to tie for the second-lowest minimum on record in late February. It has since recovered in April, and is currently on the low end of the historical range.
The post State of the climate: 2025 close behind 2024 as the hottest start to a year appeared first on Carbon Brief.
State of the climate: 2025 close behind 2024 as the hottest start to a year
Jackie Chesnutt, who lives outside San Angelo, is tired of pollution from wells she says should have been plugged years ago. Experts say Texas rules allow companies to defer plugging wells for far too long.
Reporting for this story was supported by a grant from the Fund for Investigative Journalism.
Low-Producing Oil Wells in Texas Cause Headaches for Landowners
An interview with author Catherine Coleman Flowers.
The fourth installment in our special Earth Day series
When the sciences and the humanities; democracy and ecology, are all under common and increasing attack, the efforts of independent experts and researchers matter more than ever.
David Ritter
So often in life, our most authentic moments of joy are the result of years of shared effort, and the culmination of a kind of deep faith in what is possible.
A few weeks ago, I had the honour of being in Canberra, along with some fellow environmentalists and scientists, to witness the enactment of the High Seas Biodiversity Bill 2026 by our federal parliament.
This was the moment that the Global Ocean Treaty—one of the most significant environmental agreements of our time—was given force through a domestic Australian law.
If you are part of the great Greenpeace family, you will know exactly why this was such a huge deal. The high seas make up around 60 per cent of the Earth’s surface and for too long, they have been subjected to open plunder. Now, for the first time in human history, there is an international instrument that enables the creation of massive high seas sanctuaries within which the ocean can be protected. This is a monumental collective achievement by Greenpeace and all the other groups who have campaigned for high seas marine sanctuaries for many years.
But as momentous as the ratification was, the parliamentary proceedings were distinctly lacking in drama or fanfare–so much so, that Labor MP backbencher Renee Coffey felt the need to gesture to those of us in the gallery with a grin, to indicate that the process was over and done.
The modesty of the moment had me thinking about the decades of quiet dedication by many hands that are invariably required to achieve great social change. In particular, I found myself thinking about researchers. So much of the expert academic work that underpins achievements like the Global Ocean Treaty is slow, painstaking, solitary—and often out of sight.
I think of the persistence and tenacity of researchers as an expression of love, founded in an authentic sense of wonder and curiosity about the world—and frequently linked to a deep ethical desire to protect that source of wonderment.
In 2007, one of the very first things I was given to read after starting with Greenpeace as an oceans campaigner in London was a report entitled Roadmap to Recovery: A global network of marine reserves. Specific physical sensations can tend to stick in the mind from periods of personally significant transitions, and the tactile reminiscence of holding the thin cardboard of the modest grey cover of that report is deeply embedded in my memory. I suspect I still even have that original copy in a box somewhere.
Written by a team of scientists led by Professor Callum Roberts, a marine conservation biologist from the University of York, the Roadmap provided the first scientifically informed vision of a large-scale global network of high seas marine sanctuaries, protecting the world’s oceans at scale. Of course, twenty years ago, this idea felt more like utopian science fiction, because there was no Global Oceans Treaty. But what seemed fanciful at the start of this century is now possible-–and I have every confidence the creation of large scale high seas marine sanctuaries will now happen through the application of ongoing campaigning effort—but we would never have gotten this far without the dedication of researchers, driven by their love of the oceans. And now here we are, with the ability for humanity to legally protect the high seas for the first time.
Campaigning and research so often work hand in hand like this: the one identifying the need and the solutions; the other driving the change. Because in a world of powerful vested interests, good science alone doesn’t shift decision makers—that takes activism and campaigning—but equally, there must be a basis of evidence and reason on which to build our public advocacy.
So, I want to take a moment to think with love and appreciation for everyone who has contributed to making this possible. I’ve never met the team of scientists who authored the original Roadmap, so belatedly but sincerely, then, to Leanne Mason, Julie P. Hawkins, Elizabeth Masden, Gwilym Rowlands, Jenny Storey and Anna Swift—and to every other researcher and scientist who has been involved in demonstrating why the Global Oceans Treaty has been so badly needed over the years—thank you for your commitment and devotion.
And to everyone out there who continues to believe that evidence and truth matter, and that our magnificent, fragile world deserves our respectful curiosity and study as an expression of our awe and enchantment, thank you for your conscientiousness.
When the sciences and the humanities; democracy and ecology, are all under common and increasing attack, the efforts of independent experts and researchers matter more than ever. You have Greenpeace’s deepest gratitude. Every day, we build on the foundations of your work and dedication. Thank you.
Q & A
I have been asked several times in recent weeks what the ongoing war means for the renewable energy transition in Australia.
While some corners of the fossil fuel lobby and the politicians captured by these vested interests have been very quick to use this crisis to call for more oil exploration and gas pipelines, the reality is that the current energy crisis has revealed the commonsense case for renewable energy.
As many, including climate and energy minister Chris Bowen have noted, renewable energy is affordable, inexhaustible, and sovereign—its supply cannot be blocked by warmongers or conflict. People intuitively know this; it’s why sales of electric cars have climbed to an all-time high, it’s why interest in rooftop solar and batteries has skyrocketed in recent months.
The reality is that oil and gas are to blame for much of the cost-of-living pain we’re feeling right now; fossil fuels are the disease, not the cure. If Australia were further along in our renewable energy transition and EV uptake, we would be much better insulated from petrol and gas price shocks and supply chain disruptions.
Yes, we need short-term solutions to ease the very real cost-of-living pressures that Australian communities and workers are facing as a result of fuel shortages. While replacement supplies is no doubt a valid step for now—Greenpeace is also backing taxes on the war profits of gas corporations to fund relief measures for Australians—in the long term, we will only get off the rollercoaster of fossil fuel dependency and price volatility if we break free from fossil fuels and accelerate progress towards an energy system built on 100% renewable energy, backed by storage.
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