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.
As a "cloud person", I just want to add a few things to the description of how clouds affect the climate (and why high clouds have a wamring effect).
All clouds are white, so they all reflect sunlight back into space (during the day), cooling the Earth.
All clouds are (almost) black in the infra-red, meaning the amount of energy they emit in the infra-red is determined by their temperature. Colder clouds emit less energy.
Almost all clouds are colder than the surface beneath them, which means they emit less infra-red energy to space than a clear day would. This reduces the amount of energy the Earth emits to space, so warming the climate.
High clouds are colder than low clouds, so have a stronger warming effect.
I have a question for a cloud person, maybe you can answer it.
When it rains, where does the latent heat go? The latent heat of evaporation (or condensation) is absolutely huge. Condensation means heat is released. I did a back of the envelope calculation. 2 mm daily rainfall x 500 million km2 = 10^15 kg; each kg of water holds 2.26 MJ of latent heat, and there are 86400 seconds in a day, so that's 26.15 W, so overall 26150 TW. The Earth receives about 173000 TW from the Sun, so this is about 15% of the energy received from the Sun. Obviously, not all the 15% goes out to space, but about how much does go to space?
It heats up the atmosphere and eventually gets emitted back into space!
For the Earth's temperature to remain approximately constant, the energy leaving the system (as infra-red) has to balance the energy entering the system (as sunlight).
The atmosphere is almost transparent to visible light, so sunlight doesn't really heat the atmosphere at all, it mostly heats the surface.
In contrast, the atmosphere is mostly opaque to infra-red (apart from the 'window region' at about 10um), which means energy is mostly emitted from higher levels in the atmosphere.
This means that you have to have a way of getting energy from the surface (were it effectively 'arrives') to higher levels in the atmosphere (where it can leave the Earth system again. Latent heat is an important way for this to happen - you can see it in this figure, showing how energy flows in the Earth system
I didn’t install the plug-in, but made a mental substitution and reread the thread. Now I am chuckling like a grade schooler over some madlibs and dribbled coffee down my shirt.
Cloud computing energy use appears to be on an exponential trend driven by general trends (all things automated), with new forms of automation compounding competitive pressures (deep learning models quickly getting larger, more powerful, more useful, and more versatile in a way erasing many lines holding back past competition.)
At some point, it seems inevitable that computing usage will be a first level climate driver, regardless of how green the energy is.
Harnessing orbital solar, fission and fusion power, may solve the CO2 energy problem, without requiring us to steal the biosphere's energy needs, but will eventually create a massive waste heat energy problem.
Unless we find someway to efficiently transfer mass amounts of heat energy off of Earth.
Or we eventually limit computing on Earth, and export that to the Moon and beyond.
Not all water vapor is clouds. Where relative humidity is too low it comes with all the warming but none of the cooling effect. A tiny change in humidity (cloud/no cloud) can change things significantly.
This IR satellite view of clouds and water vapor centered over N/S America is pretty nice. You can also see the daily pulse of cloud formation over the Amazon rainforest:
That's interesting. How relevant is energy transport in comparison to the optical effects?
Eg: my understanding is that hurricanes are net cooling because they transport heat from the ocean surface to the upper atmosphere. Presumably the same can be said for cumulonimbus/thunderheads? Or perhaps it is more relevant when they form in the day and when they dissipate at night?
This is related to my reply above, but clouds in general move heat upwards in the atmosphere through latent heating.
When you evaporate water from the surface, you cool it (like sweating keeps you cool). This water vapour is then lifted by convection until it cools enough to condense and form a cloud. As the water vapour condenses, the opposite happens and it heats the atmosphere locally (this further invigorates the convection)
Once you have condensed enough water (and the water droplets/crystals are large enough), you form precipitation. This falls back to the surface (some evaporates along the way), where the process starts again.
This transporting of energy through the water cycle is an important component of how energy moves in the Earth system - you can see it on this figure as 'latent heating', moving energy away from the surface at something like 80Wm^-2
I will give you the benefit of doubt given it's Hacker News you likely are an expert, but this feels like one of those "sounds too intuitive to be that simple" type complex factors. Any literature on the topic from which I can improve my understand?
What part of it do you doubt? It’s obvious that clouds are white, and it’s obvious that they are cooler than the earth and even colder higher up (clouds form because the adiabatic expansion of rising air cools it down and causes water to condense, and the higher up you go the colder the atmosphere due to greater expansion - anybody who has hiked the mountains has experienced this).
The only assertion here that one has to take on faith is that clouds are approximate black bodies at infrared wavelengths (which isn’t surprising - most things tend to be), and the relative magnitude of the cooling vs warming effects. Oh and there is an unstated dependency that the Earth is also an approximate black body at infrared wavelengths.
I think the concept of the albedo of the poles is another simple idea that explains why melting poles would be bad and accelerate global warming further, because by being white they reflect back sunlight for a huge area. Kinda intuitive if you have ever touched the black (opposite color) coolers on a desktop computer and felt your hand fry
Granting that the two effects counteract each other, it is surprising that the crossover point would happen within the range of variation of actual clouds on Earth. My uninformed guess would have been that nearly all clouds' effects are dominated by only one of the two effects—probably, by the cooling effect.
The PR part also applies to Earth Observation Satellites (ESA and EUMETSAT). (Almost) any time you see a wide area picture of the Earth from Space (particularly around a weather event), it comes from NASA's MODIS instrument [e.g. 0].
The European (approximate) equivalent, AATSR, had a lot of really nice scientific qualities, but it was missing a blue channel, meaning that the 'true-colour' images it produced always had a blue tint to the clouds. There was a similar problem with the European geostationary satellite imager (SEVIRI) [1].
Scientifically, SEVIRI was incredibly useful (and far in advance of the American equivalent at the time), but the lack of a blue channel meant that it was never really used for those shots that made it onto the news (and neither was AATSR). When you have spent multiple billions on a satellite programme, you generally want the public to see it.
I remember being told at one point that this was considered such an issue that the Europeans would 'never launch a satellite without a blue channel again' - although that might be overstating it a little.
It’s funny how well that fits in with cultural stereotypes. The US had an insane culture of self promotion and salesmanship. Europe has a culture of intense elitism. ESA designed an excellent satellite that focused on the “right” goals, and promptly forgot the dirty peasants whose money they were really spending.
Similarly, the Hubble Space Telescope has done more to raise and advance interest in space among the commons than anything else in unmanned space exploration.
It shouldn’t be surprising. Unless you’re operating outside of a regime of democracy, you have to convince the majority (i.e. very dumb people by academic standards) that it’s worth it.
https://www.theguardian.com/world/2018/nov/26/cruise-ship-ca...
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).
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/201...
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.