A coordinated response is being prepared by climate researchers debunking the whole thing, but the news story has already passed so I don’t know whether it will matter.
This is part of the trend of "there needs to be room for opposing views". Similar to when JD Vance visited Europe in February and scolded the EU on not suppressing views from elements such as AfD, which is essentially East Germany in every demographic.
When asked about the Indian Removal Act, President Andrew Jackson stated that if he had not taken the action, the native peoples would have been wiped out. Effectively he was saving them from genocide.
"According to historian H. W. Brands, Jackson sincerely believed that his population transfer was a "wise and humane policy" that would save the Native Americans from "utter annihilation". Jackson portrayed the removal as a paternalistic act of mercy."
I would say we are largely past the second threshold too (that the warming is human caused). The last IPCC report had as the first statement in the summary for policymakers (from WG1 - the physical science group)
A.1 It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred.
The previous report (from 2013) only said (and much further in)
Human influence on the climate system is clear. This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system.
The equivalent statement from AR4 (2007) was
The understanding of anthropogenic warming and cooling influences on climate has improved since the TAR, leading to very high confidence that the global average net effect of human activities since 1750 has been one of warming, ...
You could argue there is more of a question about what to do about it (e.g. try and mitigate climate change or just pay for the damanges). There is pretty good evidence at this point that mitigating the change through reducing CO2 emissions is a lot cheaper and comes with a host of other benefits (energy security, improved public health), but I can see wherer there might be arguments to have about this.
Looking at Europe for the last decade (and a bit more), the questions has only been about what strategy should be used, whom deserve to pay for it and whom should be exempted. The left and right has enough combat ground to fight over those issues that any question around the existence of global change, or if it is human caused, is just unnecessary.
OP is talking about people who reject climate change. If you know many, youll likely note most do not deny climate change but instead deny that it is man made, which is an easier delusion to maintain.
It depends on which subset we're talking about though. Some are quite well educated and (IME) lately have taken the position that sure, it's happening and sure, it's human caused but that mitigation is far too expensive and economically disruptive to justify. Thus that we should simply let things run their course and deal with any fallout as necessary.
They are starting from the conclusion of "I'm not going to lift a finger to do anything related to the climate, and the society shouldn't, either," and then they're working backwards to find arguments that justify their position.
See how easily these people switch from "Nothing is happening" to "Oops it's too late to do anything."
Your vehicle is traveling straight and there's debris in the road in front of you. If you swerve left there's an oncoming vehicle. If you swerve right there's a ditch and a power poll. You're going to hit something no matter what you do. Which is the least bad option?
It's entirely possible some of them are merely paying lip service and don't really believe that it will ever affect them personally. But taking them at their word they accept that they will be impacted one way or another.
I don't happen to agree with them but I still think it's worthwhile to understand other's reasoning. The dismissiveness that's all too common drives dogmatic behavior and polarization.
It turns out that the previous 2015 regulations around the USA and Canada were also largely followed, even offshore - this is despite there being little monitoring capability away from ports (I worked on this study).
I am not an economist, but I suspect part of the compliance is a case of 'as long as everyone is forced to do it', we are okay with it as everyone can/has to raise prices.
One thing I found really interesting abou the Graphcast paper (I appreciate this is not graphcast, but I think it is still relevant) is that it doesn't understand climate change. The model requires the training data to be recent to get the best quality projections.
While there are some factors that influence predictability in the weather forecast, as the fortran code is based on physics (at least in a broad sense), it doesn't suffer from those issues in the same way.
This doesn't mean that the ML forecasts are wrong (obviously), just different. Given the relative computational simplicity of running them, I wonder if the issue is not just expertise, but also understanding how they can best be used to generate reliable weather forecasts?
I think the one time bump could be a fair description in that is doesn't add to the long term warming rate in the same way GHGs do. The cumulative effect here is pretty much all realised within about 20 years (so not an instantaneous effect, but it could be considered a one time one?)
There is heat being continually trapped by the SLCP, which analogous to a one-time (large) release of CO2. The earth will warm up in response, and will keep absorbing heat from the SLCP as long as the pollutant is being emitted.
As we heat up, though, we'll radiate more heat back into space (blackbody) leading to a new equilibrium temperature (the trapped flux and outgoing flux are now both larger, but balanced).
If you think about it as heat, it's cumulative. If you think about it as temperature, it'll effectively lead to a ~fixed bump (not quite a fixed one-time bump, as the effects are not linear, but one can think of it that way).
The wording of the article and the paper are a bit misleading here. It is definitely a one time even (although it plays out over 20 years)
The doubling of the rate of warming only applies for the first year or two. Based on this paper, over the period 2020-2030, the impact of ship fuel regulations is warming of about 0.12K. The long term temperature trend is around +0.19K over this 10 year period.
The mechanism is different from the impact of sulphur in the stratosphere (where there are no clouds), but it is the same as the mechanisms that have caused the majority of the aerosol cooling (a brightening of clouds).
The same ze of the cooling has long been uncertain though. It depends a lot on assumptions you make about the pre-industrial atmosphere,something that we don't have great observations of.
The numbers in this study need to be interpreted carefully, the way the authors presented them doesn't really help this.
The warming rate they quote (0.24K per decade) is the instantaneous warming, which decreases over time. The warming over 10 years is actually about half of this (0.12K). While still significant, it's not a doubling of the warming rate (which is around 0.19K per decade).
The forcing being equal to 80% of the heatuptake is also interesting, but we have not seen such a large step change in energy imbalance in the Earth system. This doesn't mean they are wrong about the forcing estimate, but it does not mean that 80% of the warming since 2020 has been due to ship fuel regulations either.
Water vapour is a very strong infrared absorber, so much so that it is more important for the greenhouse effect than CO2. However, it is usually very difficult to change the amount of water vapour in the atmosphere as a whole (it just rains out).
The stratosphere cycles through much slower than the troposphere (there are very few clouds, for example). That means that if you put water there, it can stay there for a lot longer, increasing the total amount of water in the atmosphere and warming the climate.
I'll also say that we expect water vapour to increase as temperature increases, which is a positive feedback in the climate system,increasing the warming beyond that of CO2.this is known as the water vapour feedback.
- "That means that if you put water there, it can stay there for a lot longer"
There's more to it than that. Large parts of the water bands in the troposphere are already saturated: adding more and more of the same absorbing material doesn't have a linear effect, but diminishing returns. But the stratosphere is completely dry. The marginal effect of a water unit is a lot greater.
The increase in humidity is actually a different effect - evapotranspiration from trees is included in climate models (along with their response to increasing CO2 concentrations) [0].
The effect in this article is more to do with the particulates that form from the chemical emitted from trees. The article doesn't make it clear, but an increase in tree particulates (known as aerosols) would actually cause less rain.
Almost all cloud droplets form on an aerosol particle, so the cloud droplets in a cloud with more aerosols are on average smaller (as the water is spread out over more droplets). These smaller droplets take longer to grow large enough to form rain, an effect which is thought to decrease the amount of precipitation in some regions (although by a small amount).
This effect is also included in climate models, but the sources of aerosol (such as from trees) are more uncertain [1], producing the uncertainty in future climate projections.
https://www.energy.gov/sites/default/files/2025-07/DOE_Criti...
It is really just a collection of 'skeptic' arguments form the last 20 years or so. Science magazie had an article about it
https://www.science.org/content/article/contrarian-climate-a...