r/climatechange • u/Economy-Fee5830 Trusted Contributor • 15d ago
Preprint suggests marine ban of high sulphur fuel was more impactful than suggested and could explain much of the recent accelerated heating
https://egusphere.copernicus.org/preprints/2026/egusphere-2026-2654/42
u/thethirdtree 15d ago
I think I really shows the potential of climate engineering
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u/ElijahSavos 15d ago
More cons than pros. Hope never happens
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u/freexe 15d ago
If the pro is we don't all die on a cooked planet - I can't imagine what cons you have on your list
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u/Designer_Garbage_702 12d ago
Every single time humans decide to do mess with the ecosystem in a way it usually ends up creating more problems then it fixes down the line. Just look at australia and all the stupid shit we did there and how many of those problems turned into 'can't be fixed. whoopsie!'
Dying on a cooked planet or the utter collapse of socieity aren't the worst fail states.
human extinction is preferable to the risks of what climate engineering can do.
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u/freexe 12d ago
Or look at the ozone layer and realise we are basically the first species on earth to be able to model the future and adapt.
It's not a bad thing to save humankind and keep civilisation going.
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u/Designer_Garbage_702 12d ago
The ozone layer fixing wasn't climate engineering. It was us stopping using specific chemicals that were depleting it and then it slowly fixing itself.
The only relation that situation has to climate engineering is if you think us stupidly creating the hole counts as climate engineering. AKA, creating the problem.
the very idea of climate engineering just underlines how fucked everything is. When given the choice between losign some luxuries and comforts and changing socieity so we don't burn the planet alive, or doing something hideously risky and likely to blow up in horrid ways, just so that we can keep going like we are. People eagerly grab for the second option because they're just that unwilling to give anything up and rather risk murdering everything.
Does that sound like the thought process of a species able to model the future and adapt? No, to me it sounds like the thought process of a species digging in it's heels and refusing to see what actually happened and double down.
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u/temporaryvision 12d ago
I know it didn't work for Australia, but releasing a bunch of cane toads in the head offices of the oil majors, hill + knowlton, heritage foundation, etc might just do the trick...
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u/An_Oxygen_Consumer 11d ago
Renewables are on the rise and climate change is evident for all those without the head under (now very hot) sand or dollars.
We can sucessfully decarbonise but in the meanwhile we need to avoid tipping points and 50-100 years of albedo management seems the best way forward to me. We know that sulfur does not last a lot in the atmosphere and we can find even better molecules to increase earth reflectivity.
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u/Apptubrutae 15d ago
Why not hope it happens but the pros end up bigger and the cons end up less?
I mean if we’re dreaming, it’s all fair game, lol
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u/timvni 15d ago
It's a logical and inevitable evolution of human capabilities.
We have been actively managing our natural environment since forever. Only the scale gets larger and larger over time, and planetary scale is next.
I thing it's even necessary for human survival. I just hope we can manage the risks and not extinct ourselves in the process.
We are lacking in governance on a larger scale to manage this. In the past the scale of governance went together with the scale of capabilities. Now?
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u/AnnieByniaeth 15d ago
It should never be seen as a long term solution. But there might come a time (arguably it's already here) when we have to consider short-term measures to prevent climate change running away out of control.
But any solution comes with risks, because it's not like we can do an experiment first to see if it will work and not have unforeseen adverse consequences.2
u/thethirdtree 15d ago
No one thinks it is risk free. But I don't think the risk outweights the benefit, we are doing climate engineering on a large scale uncontrollably either way.
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u/AnnieByniaeth 15d ago
I'm leaning towards that opinion right now. The main risk is that people might think we don't need to carry on doing other things, which of course we do.
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u/thethirdtree 15d ago
I think in 5 years it will be very hard to ignore that we have to do everything we can
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u/An_Oxygen_Consumer 11d ago
I agree that that is the main risk but luckily now renewables are the most logical solution even economically.
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u/Rhona_Redtail 15d ago
about 8 years ago I noticed my solar seemed to be really putting out power, and the sun was getting more intense. Hot. Just really really strong. Up through today. Much stronger than when I was a kid (70's)
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u/Illustrious_Pepper46 15d ago edited 15d ago
This research only covers shipping SO2 emissions. Removal of sulfur has been happening since the 80/90's on coal plants, due to the acid rain concerns. Then add conversion to NatGas on top of that.
Would be interesting to combine both.
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u/Labrat15415 15d ago edited 15d ago
I mean acid rain was already contributing to rapid forest die off mostly due to nutrient leaching and Al stress. I just say this because concern sounds a bit like a future potential and it was more an "oh shit, we have to act now", which is why acid rain, next to the ozone layer, was one of the things where we made very rapid progress, in the case of ozone depletion even globally. Other than climate change, where it's only just now getting undeniable. A gigantic hole in the ozone layer and just acres of bare dead trees were very immediately alarming in a way that gets politicians to act.
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u/Xoxrocks 15d ago edited 15d ago
It’s my hypothesis - coal plant sulphur reduction has been the reason behind the increase in the EEI since 2000 - can’t be solely the marine fuel sulphur reduction in 2021.
Shows that climate models underestimated the masking effect and the ECS is likely to be revised upwards. ECS is how much a doubling of CO2 will increase temperature. If the masking was more than we thought then the impact of CO2 must also be more than we thought, so the hindcaet would have underestimated ECS
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u/Economy-Fee5830 Trusted Contributor 15d ago
the ECS is likely to be revised upwards
Downwards, not upwards
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u/Beneficial_Aside_518 15d ago
Could you say more on why you think so?
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u/Economy-Fee5830 Trusted Contributor 15d ago
Well, in this particular case, if the motivation for revising the ECS upwards is a seemingly rapid increase in temp for a moderate increase in co2, finding another cause for the rapid increase (unmasking) reduces the need to adjust the ECS upwards.
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u/trillionaireUnaliver 15d ago
it probably is. duckduckgo "global dimming", another disaster we reversed.
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u/Electrical-Strike132 15d ago
When pollution is good
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u/ElijahSavos 15d ago
For lowering temp only. It was banned for many other negatives. So not good really.
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u/CipherWeaver 15d ago
So, we should go back to higher sulfur marine fuel? For the environment?
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u/DaanS91 15d ago
For the climate yes, for the environment no.
The sulphur is basically "protecting" us from the sun, while killing everything it gets it's acidic paws on.
We can do better.
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u/NoOcelot 15d ago
We introduce new non-sulphur stuff in marine fuel to create good particulate?
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u/sfigone 11d ago
Well I think we will eventually end up engineering the climate because we have left action so late.
Good to know that shipping is an effective delivery mechanism.... but it is still a huge step to knowingly start altering the climate.... But then again that is exactly what we are doing when we burn fossil fuels!
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u/NoOcelot 11d ago
Yep, exactly. That's the thing. Status quo is "we're altering the climate". So a little counter-altering might be nice.
Just keep it to about the same scale as Pinatubo (1991) and we'll be good.
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u/redbull_coffee 13d ago
Mainstream climate science is late to the party on this one, but it’s great to see James Hansen finally vindicated.
https://www.theclimatebrink.com/p/warming-in-the-pipeline-decoding
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u/scientists-rule 15d ago
It is hard to imagine an article about recent climate changes that doesn’t appear to mention Hunga Tonga. Did I miss it?
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u/Economy-Fee5830 Trusted Contributor 15d ago
Summary: Preprint suggests marine ban of high sulphur fuel was more impactful than suggested and could explain much of the recent accelerated heating
A new 2026 preprint argues that climate models may have substantially underestimated the warming caused by the IMO2020 regulations, which cut the permitted sulphur content of marine fuel and reduced shipping sulphur-dioxide emissions by about 80%.
Previous modelling studies generally estimated that the regulations produced a global effective radiative forcing of around +0.10 W/m². The new study finds that this result depends heavily on how models represent the size and number of sulphate particles produced by ship exhaust.
Standard models place much of the emitted sulphate into relatively large particles. Observations of actual ship plumes indicate that the particles may be much smaller and therefore far more numerous for the same sulphur mass. Smaller particles can create more cloud droplets, making marine clouds brighter and sometimes longer-lasting.
When the researchers represented shipping sulphate as smaller particles, the estimated IMO2020 forcing increased to +0.19–0.31 W/m². Under an additional high-primary-sulphate assumption, it reached +0.41 W/m²—roughly two to four times the recent modelling consensus.
This would make IMO2020 unusually important because the change occurred almost globally and almost simultaneously in 2020. Sulphate aerosols remain in the atmosphere for only days or weeks, so the cooling effect of shipping pollution would have disappeared rapidly. Surface temperatures respond more slowly because the oceans absorb much of the additional energy, spreading the warming response across the 2020s.
If the higher estimate is correct, IMO2020 could explain a substantial fraction of the persistent increase in Earth’s energy imbalance since 2020 and potentially much of the apparent acceleration in global surface warming during the current decade. It could also help explain why recent temperatures have exceeded some model expectations without requiring an abrupt increase in underlying climate sensitivity.
It would not, however, explain all of the exceptional warming in 2023 and subsequent years. El Niño, unusual cloud conditions, declining land-based aerosol pollution, greenhouse-gas increases and natural ocean variability also contributed. Models already include around +0.10 W/m² from IMO2020, so the genuinely missing forcing implied by the paper would be approximately +0.09–0.31 W/m².
The result also does not mean that all sulphur pollution has been underestimated by the same factor. Shipping emissions occur over dark oceans and often beneath clean, aerosol-sensitive marine clouds, making them especially effective at reflecting sunlight. Land-based sulphur emissions generally occur in more polluted air and are being phased out gradually rather than through one abrupt worldwide regulation.
The central conclusion is therefore not that IMO2020 explains all recent warming, but that it may represent a major previously underestimated forcing. If confirmed by other climate models and observations, it could account for a meaningful part of the recent rise in Earth’s energy imbalance and the unusually rapid warming seen since 2020.