The world experienced its second-warmest May since records began this year, a month in which climate change fueled a record-breaking heatwave in Greenland, scientists said on Wednesday.
Last month was Earth's second-warmest May on record - exceeded only by May 2024 - rounding out the northern hemisphere's second-hottest March-May spring on record, the EU's Copernicus Climate Change Service (C3S) said in a monthly bulletin.
Global surface temperatures last month averaged 1.4 degrees Celsius higher than in the 1850-1900 pre-industrial period, when humans began burning fossil fuels on an industrial scale, C3S said.
That broke a run of extraordinary heat, in which 21 of the last 22 months had an average global temperature exceeding 1.5C above pre-industrial times - although scientists warned this break was unlikely to last.
"Whilst this may offer a brief respite for the planet, we do expect the 1.5C threshold to be exceeded again in the near future due to the continued warming of the climate system," said C3S director Carlo Buontempo.
The main cause of climate change is greenhouse gas emissions from burning fossil fuels. Last year was the planet's hottest on record.
A separate study, published by the World Weather Attribution group of climate scientists on Wednesday, found that human-caused climate change made a record-breaking heatwave in Iceland and Greenland last month about 3C hotter than it otherwise would have been - contributing to a huge additional melting of Greenland's ice sheet.
"Even cold-climate countries are experiencing unprecedented temperatures," said Sarah Kew, study co-author and researcher at the Royal Netherlands Meteorological Institute.
The global threshold of 1.5C is the limit of warming which countries vowed under the Paris climate agreement to try to prevent, to avoid the worst consequences of warming.
The world has not yet technically breached that target - which refers to an average global temperature of 1.5C over decades.
However, some scientists have said it can no longer realistically be met, and have urged governments to cut CO2 emissions faster, to limit the overshoot and the fueling of extreme weather.
C3S's records go back to 1940, and are cross-checked with global temperature records going back to 1850.
© Thomson Reuters 2025.
24 Comments
Blacklabel
except for,,,..last year?
so this year was cooler.
virusrex
Which is still a clear, unequivocal trend towards higher and higher temperatures exactly as predicted by the scientists, nobody (at least nobody rational) expect a homogeneous and precise elevation of the temperature equal every year, global climate is not such a simple system.
Blacklabel
So last year being hotter than this year is a trend.
a downward one.
Sven Asai
That all efforts and data squeezing didn't succeed in coming up with the hottest May ever surely soon will have some consequences and vacant positions among them. lol
therougou
I'm not denying global warming, but that is still one misleading title...
virusrex
No, that is not a trend in the context of the global changes being experienced currently thanks to human activity, the overall trend is still towards higher temperatures even if (as expected) not every measurement results in precise and homogeneous increase. I guess you also think people with hypertension are continuously improving because their diastolic pressure always is lower than their systolic, even if the mean pressure is higher and higher.
This only betrays a deep lack of scientific literacy, absolutely none of the predictions and models about climate change depend on measurements always being higher as you apparently think, this is exactly what the data suggest and what scientists expect.
virusrex
What is misleading about it? It is what is recorded and there is no controversy about it, it is also completely congruent with climate change.
plasticmonkey
Once again you've smashed through the facade of scientific empiricism!
Bravo, sir!
Desert Tortoise
42 c today where I live. Ooof. 11:00 pm and still 36 c.
Underworld
Blacklabel
Nope. It show that the upward trend isn't a rogue case, because this year is hotter than any other year before last year.
iraira
Seriously? You can't be serious! Climate change is a trend over a long period of time. Looking at a one or two year span tells you nothing about the ultimate changes occurring. You knew this already. Stop acting ignorant.
Blacklabel
all that and I am also correct too!
True or False: last year was warmer than this year.
answer? True.
Blacklabel
If you refuse to allow to compare any one year to any other year, you can’t say anything has a “trend”.
Jimizo
No. This year may be hotter. We don’t know yet.
The comparison is the month of May, not the year.
Please pay attention to important things like this. It isn’t a minor detail.
Tokyo Guy
This thread is why the US is going to be considered a joke in the scientific world in a few years from now. This proud flaunting of ignorance.
Blackstar
@Blacklabel
If you refuse to allow to compare any one year to any other year, you can’t say anything has a “trend”.
Obviously most people, even children from around 10 years old, would understand that you need to look at a more complete set of data than 2 years. As you surely know, the trend over the past 10-15 years is stunning and totally unmistakable when (if) you look at it. Barring some kind of miraculous tech innovation, and/or the arrival of a couple of great world leaders, we're almost certainly ....ed, in other words.
ian
1.5 threshold already exceeded.
Emissions are continuing to be added to the atmosphere nonstop, what causes the average global temp to go down if the emissions is the main cause of the temp going up?
Ah_so
You obviously know that this is not a serious argument, given that you obviously are aware that trends form over decades, not a couple of years.
Blacklabel
so compared “this year” (just May, really) to every other year BUT last year (the hottest one)
why did you exclude one specific data point?
The only reason to do that is if last year (the hottest one) is an obvious “outlier” and needs to be thrown out.
was last year an “outlier” that is not aligned with all other years?
ian
There's no reason for the may of this year to have a lower average temp than the may of last year if the main driver is the amount of emissions in the atmosphere.
that a whole years worth of emissions
virusrex
Not if you want to use the word "correct" in its valid meaning.
Pretending that normal variations conform a trend while ignoring what is actually conforming a trend only betray a deep ignorance of how the word is used. The hypertension example is clear enough.
Trends are defined over as much data points as possible for a given scale. Not two points.
The one trying to exclude all the data points that conform a trend is you, pretending that climate change is the only thing that could have an effect on a two year period is also invalid.
virusrex
No, it is part of the expected variation from many different factors, all perfectly congruent with what climate change produces.
Blacklabel
Oh a “variation”, I see.
“Variation: “a change or difference in condition, amount, or level, typically with certain limits.”
something has changed since last year. Something is…different.
That would be the previous trend, changing from “hotter”to….not hotter.
thank you for your attention to this matter!
plasticmonkey
I definitely believe this guy’s claim that he holds multiple postgrad degrees in the sciences.