From Watts Up With That?

By Charles Rotter

Abstract

Global mean sea surface temperature (GMSST) is a fundamental diagnostic of ongoing climate change, yet there is incomplete understanding of multi-decadal changes in warming rate and year-to-year variability. Exploiting satellite observations since 1985 and a statistical model incorporating drivers of variability and change, we identify an increasing rate of rise in GMSST. This accelerating ocean surface warming is physically linked to an upward trend in Earth’s energy imbalance (EEI). We quantify that GMSST has increased by 0.54 ± 0.07 K for each GJ m^–2 of accumulated energy, equivalent to 0.17 ± 0.02 K decade^‒1 (W m^‒2) ‒¹. Using the statistical model to isolate the trend from interannual variability, the underlying rate of change of GMSST rises in proportion with Earth’s energy accumulation from 0.06 K decade^–1 during 1985–89 to 0.27 K decade^–1 for 2019–23. While variability associated with the El Niño Southern Oscillation triggered the exceptionally high GMSSTs of 2023 and early 2024, 44% (90% confidence interval: 35%–52%) of the +0.22 K difference in GMSST between the peak of the 2023/24 event and that of the 2015/16 event is unexplained unless the acceleration of the GMSST trend is accounted for. Applying indicative future scenarios of EEI based on recent trends, GMSST increases are likely to be faster than would be expected from linear extrapolation of the past four decades. Our results provide observational evidence that the GMSST increase inferred over the past 40 years will likely be exceeded within the next 20 years. 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.

https://iopscience.iop.org/article/10.1088/1748-9326/adaa8a

Of course, the news stories were all teed up ready to publish the moment the embargo was lifted.

Ocean-surface warming four times faster now than late-1980s

Ocean temperature rise accelerating as greenhouse gas levels keep rising

The surface of our oceans is now warming four times faster than it was in the late 1980s

Another day, another climate “crisis” declared by scientists who seem more interested in pushing policy than in practicing rigorous, unbiased science. The latest entry in this parade of alarmism comes from Merchant et al., who claim to have proven that sea surface temperature (SST) is accelerating at an alarming rate due to Earth’s Energy Imbalance (EEI). Their solution? The usual—immediate and severe reductions in fossil fuel use. But before we surrender modern civilization to the dictates of climate activists, let’s take a closer look at this paper and see if its conclusions hold up.

Spoiler: They don’t.

The House of Cards Built on Uncertain Data

The foundation of Merchant et al.’s argument is that Earth’s oceans are warming faster than before, and this acceleration is due to a growing energy imbalance. The problem? The data they use to reach this conclusion is riddled with uncertainty.

They rely heavily on satellite observations to measure EEI, the supposed imbalance between incoming solar radiation and outgoing heat. However, they openly admit that the absolute accuracy of these measurements is not precise enough to detect imbalances as small as ~1 W/m² with confidence. In other words, they are trying to measure a trend that is smaller than the margin of error in the instruments they use. That alone should be enough to dismiss this study.

But it gets worse.

Because the data is unreliable, they supplement it with “reconstructed” EEI estimates before 2000 using a mix of proxy data and modeling. This means that nearly half their dataset is not even direct observation—it’s modeled guesswork. And yet, they use it to claim they can measure multi-decadal acceleration trends with certainty.

Acceleration? Or a Statistical Magic Trick?

If you go looking for acceleration, you’ll probably find it—especially if you design your statistical model to guarantee that outcome. That’s exactly what Merchant et al. have done.

They test three models to explain sea surface temperature trends:

1. Linear warming model – Predicts a steady, slow warming trend.
2. Quadratic model – Assumes an accelerating trend.
3. EEI-driven model – Uses their highly uncertain EEI data to “explain” why warming is accelerating.

Unsurprisingly, they find that the model assuming acceleration fits best, which is exactly what they wanted to prove in the first place. This is not science—it’s circular reasoning disguised as research.

What they don’t do is consider alternative explanations for the changes in sea surface temperature. Natural ocean cycles like the Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) can drive temperature fluctuations on multi-decadal timescales. These are well-documented, yet Merchant et al. ignore them entirely, preferring to attribute every fraction of a degree increase to human emissions.

Exaggerating Future Warming for Maximum Alarm

The authors then take their dubious acceleration trend and extrapolate it forward to claim that future ocean warming will far exceed previous estimates. They construct three scenarios:

1. On-trend – EEI continues rising, leading to catastrophic warming.
2. Moderate – Warming still accelerates but not as fast.
3. Mitigated – Even with severe emissions cuts, warming will still accelerate.

This is nothing but a glorified version of the climate doomsday scenario playbook—start with a model that assumes acceleration, plug in arbitrary assumptions about future emissions, and produce worst-case predictions that just happen to align perfectly with the climate policy agenda.

Ignoring Uncomfortable Contradictions

The study claims that EEI has been rising since around 2010 and that this is driving SST acceleration. But even they acknowledge that anthropogenic aerosol reductions (i.e., cleaner air) could be responsible for part of the observed trend. If less pollution is allowing more sunlight to reach the ocean, wouldn’t that mean past warming was suppressed by pollution, rather than proving CO₂-driven warming is out of control?

And if that’s true, wouldn’t this mean that climate models have been overestimating the role of CO₂ all along? Merchant et al. conveniently ignore these contradictions because they don’t support their acceleration narrative.

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.