In 2024, ocean temperatures reached record highs, worsening extreme weather and threatening ecosystems due to accelerating global warming.
A recent study published in Advances in Atmospheric Sciences reveals that ocean warming in 2024 has set new record-high temperatures. This marks the hottest conditions ever recorded by humans, affecting not only surface temperatures but also the upper 2,000 meters of the ocean.
“The broken records in the ocean have become a broken record,” said Prof. Lijing Cheng with the Institute of Atmospheric Physics at the Chinese Academy of Sciences. He led a team of 54 scientists from 7 countries and discussed how a hotter ocean affects our lives on land and what this means for our future.
Why is the ocean so important?
The ocean is a critical part of the Earth’s climate – most of the excess heat from global warming is stored in the ocean (90%) and the ocean covers 70% of the Earth’s surface. Because of this, the ocean dictates our weather patterns by transferring heat and moisture into the atmosphere. The ocean also controls how fast climate change happens.
“To know what is happening to the climate, the answer is in the ocean,” said Prof. John Abraham at the University of St. Thomas, coauthor of the study.
Results from three international teams who collaborated on this project were consistent – the ocean is warming, and 2024 was a record. The next image shows one set of results for the upper 2000 m ocean heat content (from the Institute of Atmospheric Physics). Blue and red colors refer, respectively, to whether a particular year was colder or hotter than the 1981-2010 period. This time period is used as a basis for scientists to compare against reference conditions. The central message is that the values have been increasing year after year after year.
From 2023 to 2024, the global upper 2000 m ocean heat content increase is 16 zettajoules (1021 Joules), ~140 times the world’s total electricity generation in 2023.
“OHC has increased steadily by 15~20 ZJ over the past five years despite the La Niña and El Niño cycles.” Said Prof. Michael Mann from the University of Pennsylvania.
The ocean surface temperature is also setting records. The surface temperature refers to temperatures just at the surface, where the ocean waters and atmosphere commute. Surface temperatures are important because they dictate how fast heat and moisture (humidity) can transfer from the ocean to the air and thus affect weather. The rise in surface temperatures since the late 1950s has been staggering.
Why does this matter?
The changes are not uniform; regional variations can be substantial. The Atlantic is warming along with the Mediterranean Sea, and across the mid-latitude Southern Ocean. While parts of the Northern Pacific Ocean have warmed very rapidly, other areas (the tropical region) have not, mostly due to the La Nina/El Nino cycle in that area. The heat has even accumulated near both the North and South Poles.
A warmer ocean affects marine life and results in huge damage in many ways.
“The main way the ocean continues to influence the climate is through accompanying increases in water vapor in the atmosphere that leads to the damaging increases in extremes in the hydrological cycle. Water vapor is also a powerful greenhouse gas and increased heating leads to drying and risk of drought and wildfire. But it also fuels storms of all sorts and leads to a risk of flooding. That includes hurricanes and typhoons.” Said Dr. Kevin Trenberth, a senior scientist at the National Center for Atmospheric Research, USA, another member of the team.
For example, over the past 12 months, a staggering 104 countries have recorded their hottest temperatures ever. Droughts, heat waves, floods, and wildfires have impacted Africa, Southern Asia, the Philippines, Brazil, Europe, the USA, Chile, and the Great Barrier Reef, as just but a few examples. Since 1980 for example, climate disasters have cost the USA nearly $3 trillion.
The heat in the ocean is the best measurement for monitoring the changing climate. “The ocean is our sentinel for planetary warming, acting as the major sink of surplus heat accumulating in Earth’s climate system as a result of anthropogenic emissions,” said Dr. Karina von Schuckmann at Mercator Ocean International, coauthor of the study. If there continues to be a failure to take action to slow climate change, the disruption, unprecedented change and its implications, costs and loss, and damages will continue to increase.
Reference: “Record High Temperatures in the Ocean in 2024” by Lijing Cheng, John Abraham, Kevin E. Trenberth, James Reagan, Huai-Min Zhang, Andrea Storto, Karina Von Schuckmann, Yuying Pan, Yujing Zhu, Michael E. Mann, Jiang Zhu, Fan Wang, Fujiang Yu, Ricardo Locarnini, John Fasullo, Boyin Huang, Garrett Graham, Xungang Yin, Viktor Gouretski, Fei Zheng, Yuanlong Li, Bin Zhang, Liying Wan, Xingrong Chen, Dakui Wang, Licheng Feng, Xiangzhou Song, Yulong Liu, Franco Reseghetti, Simona Simoncelli, Gengxin Chen, Rongwang Zhang, Alexey Mishonov, Zhetao Tan, Wangxu Wei, Huifeng Yuan, Guancheng Li, Qiuping Ren, Lijuan Cao, Yayang Lu, Juan Du, Kewei Lyu, Albertus Sulaiman, Michael Mayer, Huizan Wang, Zhanhong Ma, Senliang Bao, Henqian Yan, Zenghong Liu, Chunxue Yang, Xu Liu, Zeke Hausfather, Tanguy Szekely and Flora Gues, 10 January 2025, Advances in Atmospheric Sciences.
DOI: 10.1007/s00376-025-4541-3
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15 Comments
“Green bars indicate the measurement accuracy.”
That is not an accurate statement. The range of the ‘95% probability’ indicates the probability that additional monthly samples (say from a different database) would fall within that range. Unless there is a standard reference to compare to, one cannot be certain that the displayed monthly ‘average’ is accurate. There could be systematic errors that bias the average. The green bars are a reflection of variance of the sampled population, and the precision and accuracy of individual measurements. The sampling protocol also plays a role in the calculated results.
Furthermore, at least in meteorological temperature measurements, there is a definitional issue that is usually glossed over. That is, what is typically called the ‘average’ temperature is derived from the two daily extremes and is a special case of a median that is properly called the “mid-range” value, NOT an arithmetic mean of many samples, which is what most people associate with ‘average.’ The green ‘error bars’ are really a measure of uncertainty of the accuracy and precision (precision also rarely gets the attention it deserves, as in formal propagation of error analyses), and are strongly influenced by the variance and particularly the range. That is, an outlier in the daily high or low (two samples) will have a much greater influence on the calculated value than it would if it were one out of at least 20 or 30 samples. Yet, that mid-range value is rarely acknowledged and is almost always referred to as the “average.” Strictly speaking, it is a kind of ‘average’, but one that is NOT amenable to being characterized by the statistical descriptor parameters of mean, standard deviation, and kurtosis. Kurtosis is important because air temperatures in particular are typically highly skewed, with the daytime temperatures approximating a sinusoid, while the nighttime temperatures approximate an exponential decay curve. Furthermore, the time of sampling for Tmax and Tmin are not the same every day, and if a cold front should move through after a morning reading, the timing of the two readings could be reversed. Fundamentally, the reliance on mid-range values is unsuitable for the high-precision necessary for climatology.
The article categorically states, “… the ocean is warming, and 2024 was a record.” They don’t explain what they mean by that! Is it daytime highs that they are referring to? The mid-range values at the same location? Or, random samples day and night? Those are not trivial points when attempting to do high precision work, which is necessary with water because it warms and cools more slowly than air. However, the abstract for the peer-reviewed article claims an increase in heat content of approximately 16 ± 8 ZJ. That means there is 95% probability that even the lowest probable value (8) is positive. Although, another way of looking at this is that the estimate is 16 ± 50% ZJ . That doesn’t suggest that the results are highly accurate or precise. Another cited study has a result of 40 ± 31 ZJ or 40 ± 78% ZJ; they barely ovelap at the low end. These are hardly what I would characterize as highly precise estimates that justify radical changes in energy policy and elimination of the use of fossil fuels.
“The ocean surface temperature is also setting records. … The rise in surface temperatures since the late 1950s has been staggering.”
This article doesn’t actually give us any numbers to compare, or define “staggering.” There is a graph above, but not everyone is facile at interpreting graphical data, so I’ll give you some numbers from their actual paper and the graph above. First off, the graph clearly shows that 2024 sea surface temperatures only exceeded 2023 temperatures for the first six months of of the year; after that, 2024 temperatures were lower than in 2023. One can attribute this to the transition from El Nino to La Nina conditions, possibly augmented by the Hunga Tonga–Hunga Haʻapai eruption in 2022. However, the published journal article states the following: “The global SST continued its record-high values from 2023 …, resulting in an annual mean of 0.61°C ± 0.02°C (IAP/CAS data) above the 1981–2010 baseline, slightly higher than the 2023 annual-mean value (by 0.07°C ± 0.02°C for IAP/CAS, …” I find it questionable whether we can rely on claims of determining average SSTs to an uncertainty of ± 0.02°C. Even the journal article doesn’t go into enough detail to validate the protocol and procedures to validate the claim. In other words, 2024 may NOT have been warmer than 2023, but in any event, has been declining since July 2024. Which leads me to the conclusion that by “staggering” they mean a temperature change of about 1°C., 1% of the range from boiling to freezing. I find that remarkably stable, not “staggering.”
“1% of the range from boiling to freezing. ”
That remark is utterly irrelevant. Parts of the ocean may freeze but it ain’t anywhere near boiling. “Staggering” is also a wee bit superfluous. Although the rise in temperature may indeed induce someone to stagger, although I can’t see why.
“Parts of the ocean may freeze but it ain’t anywhere near boiling.”
Not so. The contact with submarine lava causes the water to boil. It was an attempt to provide some context to the claim about the “staggering” change. Would you have preferred my using absolute temperature (Kelvins) to calculate the percentage? Even being generous, using the coldest that ice can get on Earth, and the temperature of lava, the percentage would have been even much smaller. How would you suggest creating ‘context’ other than supplying a subjective, ambiguous modifier like “wee bit?”
You may use whatever thermometric scale you wish. Indeed I had forgotten that lavas ooze there wicked way out onto the se floor and things such as Surtsey happen from time to time, not to mention assorted smokers. So yes; you are correct; bits of ocean may indeed boil or become superheated if the pressure water is large enough.
However that part of your erudite comment was still irrelevant to the tenor of the AGH discussion in the article. The limits of those little green error bars would suggest that a warming ocean is indeed occurring, although the sampling issues to which you refer are food for thought.
Alas that some scientists lack a sense of humour.
If you are suggesting that I lack a sense of humor, you would very wrong. I can have a wicked sense of humor. However, I’m not going to excuse someone for being wrong with the excuse that they were just joking. The point that I’m generally making is that poorly supported claims are made that are presented in the imprecise language of lawyers (whether they be tenors or sopranos), rather than the precise, numerate language of physical scientists.
Those “little green error bars” reflect the variance in data, not a trend. While I agree that the oceans probably have been warming, it is ironic that to establish the tenor of their claims they chose a year (2024) when the trend apparently reversed, compared to the previous year. See, especially, the top left corner of the third graphic in the article, showing the last half 2023 and first half 2024 being unusually warm; the tenor of the last half of 2024 is cooling, rather than runaway warming as suggested by the authors.
Thank you so much for your comment. I am reading a book called the Bernoulli ‘ s Fallacy , statistical illogic and the crisis of the modern science. Your article just illustrates the misleading conclusions reached when statistics not properly used. True for the average earth temperature absolutely meaning less. Back to the oceans a common sense question: how north atlantic ocean temperature can raise when zillions of tons of arctic ice melting and being mixed with the ocean. There must be some kind of impact.
“For example, over the past 12 months, a staggering 104 countries have recorded their hottest temperatures ever.”
It would actually be surprising if new records weren’t being set with global warming. The questions is by how much have these countries increased their “staggering” hottest temperatures? Again, the claims are ambiguous. Are they peak temperatures that are being cited, or average high temperatures, or average mid-range temperatures? When claims are being made about temperature records calculated to the nearest 0.01 °C, these definitions can be important. What IS perhaps surprising is all these attempts at ‘snow jobs,’ and the temperature isn’t declining.
Thank you Clyde Spencer for again commenting on, yet another article, demonstrating the limitations/bias/pseudoscience allowed to be published by “SciTechDaily”, particularly when it comes to climate science.
Seems to be a continuing occurrence for most editions!
In my view, SciTechDaily do not pay much attention to part of its stated objectives, of a:
” … link to the most thought-provoking, well researched online items in the world of science and technology…”
What is your real aim?
Is it to unnecessarily scare the bejesus out of people -which then helps promote further junk climate science and funding …? It certainly looks that way to me.
Round and round we go …
I don’t blame ‘SciTechDaily’ for the slant the articles usually have. They work with what they are supplied with, which appears to be mostly press releases, and it doesn’t have a staff large enough to re-write all the articles. Besides, that would open them to accusations of bias if they made significant changes. While it has technical staff, they don’t make any claims to be doing original research. It only claims to provide a “link” to research. Choosing to not publish articles would defeat their purpose of aggregating current science news and make some money while doing so. Besides, the staff probably would would not agree on what to change or how.
Personally, I’m content as long as they don’t censor me and others (like Yahoo and MSN do) and allow us to point out unsupported claims and logical fallacies such as contradictory statements. I think what is unfortunate is that so many young researchers have bought into the current paradigm and rarely even acknowledge alternative interpretations, let alone discuss them and provide information to try to falsify out-of-the-box thinking. I just wish there were more people joining me with factual criticisms instead of personal insults.
Yes, thanks, noted Mr Spencer.
What I dislike the most, is the term used “well researched”, when your comments also show that this is not the case?
So I presume the prime reason for the predominant publishing of these slanted/poorly-researched articles is that there are many more of them available.
We then continue to entertain the AGW scam and its majority support, by weight of numbers and not based on facts.
As you say many more voices then, need to be heard (and not be censored), speak out publicly, publish and repeat the well-researched facts more often.
Seems like there are few volunteer experts at the moment to start the paradigm shift; perhaps the start of of an extended period of global cooling could help … 8-)).
More likely, I suggest, western economies continuing to go backwords due to over spending on green-dreams and the public revolting may finally have the desired result (of a epiphany).
It is my impression that most of the recent research in ‘climate science’ is NOT well-researched and the experiments are often not well designed. The researchers often have a cavalier attitude towards measurement statistics, often omitting uncertainty (and propagation of error) and ignoring the constraints on statistics, such as normalcy and stationarity, and the fact that mid-range medians are not as informative as arithmetic means. Considering the percentage of published medical research claims that cannot be replicated, it is not a problem unique to climatology. In contrast, I think that tremendous progress is being made in Materials Science, probably because the metric is, “Does it solve the problem we set out to solve?” and is easily verifiable. They don’t have to wait two or three decades to find out if they were wrong. While I’d like to blame our modern educational system, the success in materials science suggests that it isn’t that simple.
There have been many reasons suggested as to why poorly supported claims are made routinely, ranging from the ‘Band Wagon’ effect of researchers unwilling to stand against the majority, to simple pragmatism of academics who live and work under the requirement to “publish or perish,” and are under the (probably correct) assumption that it is easier to get published (or funded) if they carry water for the prevailing paradigm. It is my impression that one is more likely to encounter push back from retired researchers than from ‘young Turks’ who are trying to make a name for themselves. Something of an aside, when geologists were first making attempts to make numeric estimates of the age of the Earth, few were willing to bet against Lord Kelvin, whose credentials cowed most of his peers. Yet, Lord Kelvin was wrong because he didn’t know about radioactive decay.
I don’t have all the answers, therefore, I frequently ask questions here. I rarely receive acceptable answers, let alone answers that close the debate. Instead, I receive dogmatic assertions that are little more than someone parroting back the essence of the weakly-supported paradigm. It is a little surprising how indignant some become at me asking inconvenient questions for which they don’t seem to have answers.
And again Michael Mann mentionned …enough to arise some doubts
I noticed recently that Wikipedia is not up to date on the status of Mann’s legal troubles. It leaves the casual reader with the impression that Mann has been exonerated. Far from it!
See also link below, which also disputes this article’s claims:
https://wattsupwiththat.com/2025/01/28/the-ocean-warming-scare-bad-models-bad-data-and-a-clear-agenda/
It concludes:
(quote)
The Real Purpose of This Study: Climate Policy, Not Science
The biggest red flag in this paper is the authors’ final conclusion:
“Policy makers and wider society should be aware that the rate of global warming over recent decades is a poor guide to the faster change that is likely over the decades to come, underscoring the urgency of deep reductions in fossil-fuel burning.”
Notice how they jump from a scientific claim to a policy demand without hesitation? This is the true goal of the paper: to manufacture an urgent climate crisis that justifies drastic intervention.
No mention of alternative explanations for the observed warming.
No discussion of uncertainties in their methods.
No consideration of the costs or consequences of their proposed policies.
Just a predetermined conclusion wrapped in the appearance of scientific rigor.
Final Verdict: Junk Science in Service of Activism
This paper is not an objective scientific analysis—it is an advocacy document masquerading as research. It relies on uncertain data, manipulates statistical models to reinforce a preferred narrative, and exaggerates future warming to scare policymakers into action.
The truth is, given the uncertainties involved, nothing we are seeing is cause for concern. The climate has always fluctuated, and minor changes in sea surface temperature are entirely within natural variability. The only thing accelerating here is the desperation of climate activists to keep their funding and political influence intact.
The next time you see a breathless headline about “accelerating ocean warming”, remember: bad models, biased assumptions, and agenda-driven science are the real drivers behind these claims—not reality.
(end quote)