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
Climate Change
After a week of plenty of activity and drama for Greenpeace at sea, I felt like writing to you on a much quieter theme…
Do you have a favourite book, poem or story about the ocean?
When I was very small, it was the TimeLife book of The Fishes, by F. D. Ommanney, which I remember endlessly poring over, my child’s mind gripped, in total fascination. The cover illustration showed a shoal of barracuda, mid-water and heading upwards, lit up as an iridescent blue by a column of sunlight. Oddly, it is only the cover and the illustrations of the deep sea creatures which I now remember—but I loved that book, as the weakened spine, blunted pages and dog-eared corners attested.
The Fishes has been on my mind recently, because I’ve been working with some dear friends on our own illustrated oceans book, to be published by Upswell Publishing. The book is called Scott Reef: Like Nowhere Else on Earth, and I want to share with you a bit of the story behind its creation.
Scott Reef is absolutely magnificent: Australia’s largest freestanding oceanic reef, brimming with life, including rare and threatened species such as a genetically distinct population of green sea turtles, pygmy blue whales and the wonderfully elegant dusky sea snake. But Scott Reef isn’t near our capital cities; it is way off the north-west coast of WA. And it is threatened with devastation by Woodside, which wants to drill up to 57 toxic wells at the Reef for its vast, dirty Browse gas project.
One of the main challenges in the fight to save Scott Reef from being turned into an industrialised gas zone by Woodside is bringing this incredible location to life for people who haven’t actually experienced it first hand. Because despite its ecological significance and dazzling beauty, ‘Scott Reef’ is also—at least not yet—exactly a household name.
To help get over this barrier, Greenpeace has enabled a number of photographers to travel to Scott Reef by boat (including the Rainbow Warrior) to document its astonishing diversity of colour and life. We then brought these images together in a remarkable photobook, produced by our talented in-house team, which we’ve been putting into the hands of as many leaders as possible—including the MPs whose decisions can determine the Reef’s future.
Back in June this year, I was sharing a copy of our in-house book at a business gathering in Perth when someone pulled me aside. Had we thought about publishing the book commercially? Apart from anything else, he wanted to buy a copy himself! He had a point. We were proud of what we’d created, but a commercially published version could reach a much wider audience and have even greater campaign impact. I immediately turned to my dear friend, Terri-ann White, who runs Upswell Publishing in WA, for advice.
Terri-ann has a huge heart and terrific vision. So many wonderful things in WA owe their existence to her doings, and, true to form, she was immediately encouraging and enthusiastic. “But,” she said, “it would add a whole new dimension if we had some words to accompany the incredible pictures.”
Fair enough, I thought. I could ask a few authors.
“And when would you like it published?” she asked.
“Ideally November,” I answered sheepishly.
Now, in publishing terms, nobody goes from idea to finished work, beautifully produced by a commercial publisher, in just four months. It. Just. Doesn’t. Happen. A book of this scale would ordinarily take nine months, I was told. But Terri-ann was undeterred. “If you can get a rapid turnaround on the writing, I will give it a shot.”
Over the following few days, I sent out 24 emails to prospective writers. To my joy and surprise 23 of them responded almost immediately with an enthusiastic yes!
Terri-ann was somewhat alarmed and perplexed when I told her the good news… we’d discussed a few authors, not more than twenty! “Impossible,” she texted. “Editing is important and you are talking about thousands of words!” But I also know Terri-ann. She does the impossible. And so, here we are… Terri-ann is going to hit that improbable deadline. Scott Reef: Like Nowhere Else on Earth will be on shelves in November.
The contributors are a wonderfully diverse bunch, united by their enthusiasm for Scott Reef — and their extraordinary speed!
It’s a brilliant mix. The book brings together national icons like Peter Garrett, Tim Winton, Mick Dodson, Janet Holmes à Court and Fiona Stanley; the intellectual heft of professors Frank Bongiorno, Jessica Meeuwig, Rick Steiner and Samantha Hepburn; the poetic vision of Prema Arasu, Berndt Sellheim and Saadiah Freeman; the field expertise and passionate first hand witnessing of Imogen Zethoven, Tooni Mahto, Ben Fitzpatrick, Geoff Bice, Olaf Meynecke, Paul Gamblin, Sarah Gittoes and Hayley Baillie; and the determination of emerging activist voices Jackson Reid and Emma Sangalli.
Their elegant words wrap themselves around the sheer wonder of the underwater world, brought to life by the work of the photographers — of whom one, Wendy Mitchell, has also contributed a wonderful essay.
Terri-ann showed me the full physical proofs this week and they are breathtaking. This book contains some of my absolute favourite images of wildlife beneath the waves -– and believe me, after almost 20 years at Greenpeace, I’ve been privileged enough to see some remarkable shots! The essays bring a whole new depth and richness to the story of Scott Reef.
If I am being honest, and maybe a bit sentimental, I hope that a four or five-year-old child somewhere in Australia will spend part of their summer holidays turning the pages of this book, wide-eyed with curiosity and awe at the beauty and strangeness of the creatures that call our oceans home.
Our shared commitment is to make sure that, as those children grow up, the wonders of Scott Reef will exist not just in the pages of the book, but out there in the wild waters off north-western Australia—alive, thriving, and every bit as extraordinary as they are today; a living wonder beneath the waves.
Pre-orders of Scott Reef: Like Nowhere Else on Earth are available here.
Q & A
Sometimes you get asked a question so often that you decide to produce a report to answer it!
We know there is strong public opposition to voter opposition to gas drilling at Scott Reef and fracking in the Kimberley in Western Australia. But I am frequently asked whether, even if people don’t want it, more gas drilling is a necessary evil to sustain WA’s prosperity?
The short answer is an unequivocal ‘No’. The longer answer is our new report, From Gas to Green: Building Western Australia’s Future State, which makes the comprehensive case that Asia’s gas market is declining — while WA has an enormous untapped opportunity to become a global leader in green industries and exports, helping drive the region’s shift away from fossil fuels. The faster that WA embarks on a decisive shift away from gas—and that includes no fracking in the Kimberley, or drilling at Scott Reef — so much the better for the state’s people, ecology and economy.