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Earth

Pollution Cuts Have Diminished 'Ship Track' Clouds, Adding To Global Warming (science.org) 134

Paul Voosen writes via Science: Regulations imposed in 2020 by the United Nations's International Maritime Organization (IMO) have cut ships' sulfur pollution by more than 80% and improved air quality worldwide. The reduction has also lessened the effect of sulfate particles in seeding and brightening the distinctive low-lying, reflective clouds that follow in the wake of ships and help cool the planet. The 2020 IMO rule "is a big natural experiment," says Duncan Watson-Parris, an atmospheric physicist at the Scripps Institution of Oceanography. "We're changing the clouds."

By dramatically reducing the number of ship tracks, the planet has warmed up faster, several new studies have found. That trend is magnified in the Atlantic, where maritime traffic is particularly dense. In the shipping corridors, the increased light represents a 50% boost to the warming effect of human carbon emissions. It's as if the world suddenly lost the cooling effect from a fairly large volcanic eruption each year, says Michael Diamond, an atmospheric scientist at Florida State University.

The natural experiment created by the IMO rules is providing a rare opportunity for climate scientists to study a geoengineering scheme in action -- although it is one that is working in the wrong direction. Indeed, one such strategy to slow global warming, called marine cloud brightening, would see ships inject salt particles back into the air, to make clouds more reflective. In Diamond's view, the dramatic decline in ship tracks is clear evidence that humanity could cool off the planet significantly by brightening the clouds. "It suggests pretty strongly that if you wanted to do it on purpose, you could," he says.
The findings are available in a new preprint in Atmospheric Chemistry and Physics (ACP).
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Pollution Cuts Have Diminished 'Ship Track' Clouds, Adding To Global Warming

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  • What has actually happened is the the short-term effects of sulfates has dissipated and as a result, we are experiencing the full impact of our atmosphere. Ships generate and incredible amount of CO2 (one ship can emit the same as millions of cars) so this is an improvement. So yes, in the short-term it's warmer but CO2 it's not emitting will make it even hotter in the long-term.

    You still amputate an arm because while it may be painful in the short-term, the alternative is worse in the long-term.

    • by gweihir ( 88907 )

      You still amputate an arm because while it may be painful in the short-term, the alternative is worse in the long-term.

      Indeed. We can forget about those 1.5C though, as the calculations that still see us making them do not really include that effect. On track for 2C now. That will get really uncomfortable.

    • What makes you think that removing sulphur dioxide from marine diesel emissions reduces the CO2 emitted?
    • Sounds like we need to speed up the process on getting nuclear powered ships to move cargo.

      Here's one example of this process moving along: https://www.maritime-executive... [maritime-executive.com]

      Another example out of the UK: https://www.seatrade-maritime.... [seatrade-maritime.com]

      As we work out the legal issues and infrastructure for civilian ships running on nuclear power we should get more military vessels running on nuclear power. We used to have nuclear powered frigates, destroyers, and cruisers in the US Navy, we can do that again. The US Coas

  • There will be technological solutions ... all the hot air (badum ching) from politicians and obsessives is not going to solve it. Technological solutions will.
  • Which is why 1.5C is long past. We will get about 0.5C (the estimates I have seen) in addition from less pollution. As pollution kills people (fine dust does a lot of horrible things including reducing the intelligence of children and adults), this is probably still better than the alternatives, but realistically we have 2C "locked in" at this time, i.e. _nothing_ will prevent that anymore. Civilization survival is still possible if we make a real effort. Species survival is only threatened if we do not mak

  • by Baron_Yam ( 643147 ) on Thursday August 03, 2023 @06:32AM (#63736836)

    Blowing sulphur particulates into the atmosphere causes 'global dimming', which reduces the energy input into the system, keeping temperatures down despite the increasing levels of greenhouse gasses. However, the entire process and its results are bad for the environment in ways other than mere temperature.

    The simple answer appears to be 'throw something else up there that is not bad for us that will still block some sunlight', but the problem is this is too simple an answer.

    I can't see that doing anything but allowing the short-sighted to continue pumping CO2 into the air and heating up the planet, which means the aerosol injection becomes permanent if we want to have comfortable temperatures. And CO2 does more than heat us up - it is acidifying the oceans and I'm going to make a wild-ass guess that there are other less well-known effects we should also be concerned about.

    We may well need to do some solar shielding as a stop gap measure, but if we're not sucking the last 140 years of CO2 production out of the atmosphere and sequestering it (and cease to keep adding more, of course), we're delaying the inevitable and making it worse at the same time.

    • Is that they don't stay up for long. So spraying salt or something else to seed maritime clouds gives us fairly quick feedback, great localized control and if we screw it up we can stop and the aerosols will dissipate in weeks. The major disadvantage is if it works we constantly have to be doing it.
    • Neal Stephenson's Termination Shock [wikipedia.org] is a thought experiment on a massive effort to put sulfur into the upper atmosphere and some of the potential outcomes

    • by nasch ( 598556 )

      I can't see that doing anything but allowing the short-sighted to continue pumping CO2 into the air and heating up the planet

      It seems to me we're doing that anyway. If we were clearly on track to go carbon neutral in the next few decades I would agree, but it looks to me like the choice is between continuing to spew CO2 and not mitigating it, or continuing to spew CO2 and mitigating it with aerosols or something. I think at some point the situation will get so bad that it will become clear we have no choice but to try remedial geoengineering of some kind.

  • In order for sulfur compounds to cool the Earth, they have to reach the stratosphere so that's already incorrect. Also, do you know why it gets so cold in the desert? No clouds to reflect infrared. So saying sulfur-based cloud seeding causes clouds which causes cooling it completely false.
    • by XXongo ( 3986865 )

      In order for sulfur compounds to cool the Earth, they have to reach the stratosphere

      No, they are effective regardless of altitude. However lower altitude aerosols get washed out of the atmosphere quickly, so in essence you are right.

      so that's already incorrect. Also, do you know why it gets so cold in the desert?

      Actually I do. Deserts have low humidity, and water vapor is a potent greenhouse gas, so without the greenhouse gas re-emitting infrared, the surface cools rapidly.

      No clouds to reflect infrared. So saying sulfur-based cloud seeding causes clouds which causes cooling it completely false.

      Deserts may or may not have clouds. You're right, however, the net effect of clouds tends to be to cool daytime temperatures and increase nighttime temperatures. Which one wins depends a lot on deta

  • Fit the ships with giant misters and have them spray sea water into the air as they go, presumably behind the ship or in the down-wind direction.

    • Better to let the cargo ships handle cargo and built dedicated autonomous misters. The misters can run on solar and/or wind ... they don't have to get anywhere in a hurry.

  • "The Case for Climate Engineering", by Keith, is a short, digestible read on the ups and downs of spraying sulfur into the stratosphere. Frankly, it's very compelling that we already are experimenting with climate engineering - the ship fuels were an experiment to apply them, another to remove the sulfur.

    Pretending that "climate engineering" is not just *another* experiment, like every single tonne of CO2 is already an experiment, is just silly.

  • If the ocean carrier sulfur emissions were masking what should have been warming (shipping booming really since the 1960s) and since the environmental movement has had major success in removing/scrubbing widespread particulates from the atmosphere as well....then what we SHOULD have been seeing is a gradual slope general systemic warming really since the latter industrial revolution to now, right?

    Since this was masked until recently, it makes sense that "suddenly" temperatures spike upwards, say, in the las

  • Anyone interested in this might enjoy the novel "Termination Shock" by Stephenson.
    https://www.amazon.com/dp/0063... [amazon.com]
    Lots of interesting speculation on geoengineering, wrapped in a good story. A very plausible future.

  • Some of us had predicted pretty much that result.

Isn't it interesting that the same people who laugh at science fiction listen to weather forecasts and economists? -- Kelvin Throop III

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