A Problem for Sun-Blocking Cloud Geoengineering? Clouds Dissipate (eos.org) 57
Slashdot reader christoban writes:
In what may be an issue for Sun-obscuring strategies to combat global warming, it turns out that during solar eclipses, low level cumulus clouds rapidly disappear, reducing by a factor of 4, researchers have found.
The news comes from the science magazine Eos (published by the nonprofit organization of atmosphere/ocean/space scientists, the American Geophysical Union).
Victor J. H. Trees, a geoscientist at Delft University of Technology in the Netherlands, and his colleagues recently analyzed cloud cover data obtained during an annular eclipse in 2005, visible in parts of Europe and Africa. They mined visible and infrared imagery collected by two geostationary satellites operated by the European Organisation for the Exploitation of Meteorological Satellites. Going to space was key, Trees said. "If you really want to quantify how clouds behave and how they react to a solar eclipse, it helps to study a large area. That's why we want to look from space...." [T]hey tracked cloud evolution for several hours leading up to the eclipse, during the eclipse, and for several hours afterward.
Low-level cumulus clouds — which tend to top out at altitudes around 2 kilometers (1.2 miles) — were strongly affected by the degree of solar obscuration. Cloud cover started to decrease when about 15% of the Sun's face was covered, about 30 minutes after the start of the eclipse. The clouds started to return only about 50 minutes after maximum obscuration. And whereas typical cloud cover hovered around 40% in noneclipse conditions, less than 10% of the sky was covered with clouds during maximum obscuration, the team noted. "On a large scale, the cumulus clouds started to disappear," Trees said... The temperature of the ground matters when it comes to cumulus clouds, Trees said, because they are low enough to be significantly affected by whatever is happening on Earth's surface...
Beyond shedding light on the physics of cloud dissipation during solar eclipses, these new findings also have implications for future geoengineering efforts, Trees and his collaborators suggested. Discussions are underway to mitigate the effects of climate change by, for instance, seeding the atmosphere with aerosols or launching solar reflectors into space to prevent some of the Sun's light from reaching Earth. Such geoengineering holds promise for cooling our planet, researchers agree, but its repercussions are largely unexplored and could be widespread and irreversible.
These new results suggest that cloud cover could decrease with geoengineering efforts involving solar obscuration. And because clouds reflect sunlight, the efficacy of any effort might correspondingly decrease, Trees said. That's an effect that needs to be taken into account when considering different options, the researchers concluded.
Another article on the site warns that "Planting Trees May Not Be as Good for the Climate as Previously Believed."
"The climate benefits of trees storing carbon dioxide is partially offset by dark forests' absorption of more heat from the Sun, and compounds they release that slow the destruction of methane in the atmosphere."
Low-level cumulus clouds — which tend to top out at altitudes around 2 kilometers (1.2 miles) — were strongly affected by the degree of solar obscuration. Cloud cover started to decrease when about 15% of the Sun's face was covered, about 30 minutes after the start of the eclipse. The clouds started to return only about 50 minutes after maximum obscuration. And whereas typical cloud cover hovered around 40% in noneclipse conditions, less than 10% of the sky was covered with clouds during maximum obscuration, the team noted. "On a large scale, the cumulus clouds started to disappear," Trees said... The temperature of the ground matters when it comes to cumulus clouds, Trees said, because they are low enough to be significantly affected by whatever is happening on Earth's surface...
Beyond shedding light on the physics of cloud dissipation during solar eclipses, these new findings also have implications for future geoengineering efforts, Trees and his collaborators suggested. Discussions are underway to mitigate the effects of climate change by, for instance, seeding the atmosphere with aerosols or launching solar reflectors into space to prevent some of the Sun's light from reaching Earth. Such geoengineering holds promise for cooling our planet, researchers agree, but its repercussions are largely unexplored and could be widespread and irreversible.
These new results suggest that cloud cover could decrease with geoengineering efforts involving solar obscuration. And because clouds reflect sunlight, the efficacy of any effort might correspondingly decrease, Trees said. That's an effect that needs to be taken into account when considering different options, the researchers concluded.
Another article on the site warns that "Planting Trees May Not Be as Good for the Climate as Previously Believed."
"The climate benefits of trees storing carbon dioxide is partially offset by dark forests' absorption of more heat from the Sun, and compounds they release that slow the destruction of methane in the atmosphere."
If we get to 15% we're screwed (Score:2)
Our current energy imbalance looks like about 0.9 W/m^2, which is about a quarter of a percent of the 340 W/m^2 solar energy received. A bit to go before we get near 15%.
Re: If we get to 15% we're screwed (Score:2)
Wrong denominator. That 340 w/m2 is only what you get on the ground. Sunlight is 1367 w/m2 and about 400 is reflected back to space. The balance is absorbed by the atmosphere before it gets to the surface.
average versus peak [Re: If we get to 15% we...] (Score:2)
1361 W/m^2 is the direct normal extrasolar insolation, that is, what hits the top of the atmosphere at the subsolar point.
But not all the planet is noon. Half the surface area is on the night side, and of the illuminated part, cosine loss means the average insolation is half the direct normal. So the average flux hitting the top of the atmosphere is 1361/4 = 340 W/m^2.
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The 340 w/m2 is the average top of atmosphere solar irradiance, where the area is the surface area of the *whole* Earth. The entire planet isn't at noon on the equator at an equinox all the time. That's the correct denominator to go with the 0.9 W/m^2 numerator, where the area is also the whole surface area.
Your number uses the area of the disc obtained by projecting the Earth onto a plane with its normal connecting the centre of the Earth to the centre of the sun. If you could find the energy surplus with
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https://twitter.com/tonyezw1/status/1770039249921798313/photo/1
If the W/m^2 is closer to 1.4C as I believe Hansen suggests then we've theoretically got 3C of warming "locked in." Even if it's just 1C it's, well, borderline unthinkable.
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Still only 0.5%, which is a long way away from 15%. Run the calculation for temperature increase at 50 W/m^2 surplus if you disagree with my assertion that we'd be screwed at 15%.
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The article is about a study that observed clouds start disappearing when solar insolation is reduced by 15%. It's in the summary.
Well damnit (Score:3)
No shit (Score:2)
Clouds melt away at night too as the airmasses lose heat to space and sink down to where the air has a higher saturation pressure and all that condensation evaporates.
Not sure how geoengineering of this kind would fail during a once every few years eclipse but survive a daily day/night cycle. Or more precisely, I'm not sure how an analysis of geoengineering only falls apart when considering eclipses but holds up when considering the diurnal heating and cooling of the atmosphere.
Unless, of course, this geoen
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Clouds melt away at night too as the airmasses lose heat to space and sink down to where the air has a higher saturation pressure and all that condensation evaporates.
Not necessarily. Cumulus clouds tend to go away at night (they're fed by vapor-laden hot air rising due to the fact that the ground is heated) but the nocturnal decrease in temperature also means that water vapor will condense, and thus (other types of) clouds form at night. So, it depends on type of cloud, and thus on latitude and time of year.
Not sure how geoengineering of this kind would fail during a once every few years eclipse but survive a daily day/night cycle.
It's a little hard to follow their reasoning, but it seems to be that geoengineering would decrease incident flux just like a solar eclipse, and therefore there woul
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Luckily we have a full solar eclipse next month that stretches from the middle Pacific, across Mexico, US, and Canada, then out into the northern Atlantic.
That should give scientists plenty of new data to correlate or correct the hypothesis from the EOS researchers.
https://science.nasa.gov/eclip... [nasa.gov]
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Clouds melt away at night too as the airmasses lose heat to space and sink down to where the air has a higher saturation pressure and all that condensation evaporates.
That hasn't been my experience here in the Pacific Northwest... but then I do suspect some evil mastermind has a secret cloud generator hidden somewhere in the Cascades or Olympics.
Re: No shit (Score:2)
Not every time obviously, but next time the forecast calls for a clear night, pretty good chance you'll see some patches of cloud in the sky around sunset that magically disappear right around when it's possible to do any kind of astronomy.
We need to listen to scientists, not biased flora! (Score:2)
These new results suggest that cloud cover could decrease with geoengineering efforts involving solar obscuration. And because clouds reflect sunlight, the efficacy of any effort might correspondingly decrease, Trees said. That's an effect that needs to be taken into account when considering different options, the researchers concluded.
Is anyone else seeing this?! Trees want MORE sunlight, not less!! What a scandal!!! I'm literally shaking!!!
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Trees want MORE sunlight, not less!!
Let's not rush to any conclusions.
Playing with insolation is a bad idea (Score:3)
Reducing solar input reduces heat... which allows us to ignore increasing CO2 and ocean acidity. We will not use it as a respite to reduce atmospheric CO2, we'll use it as an excuse to continue making the underlying problem worse (at a faster rate, we're already continuing to make it worse).
Given the scale of such projects, we're also slaving ourselves to a massive maintenance budget (forever) that you know is going to get slashed as soon as someone doesn't feel like carrying the expense.
There are only two things we should be targeting right now - constantly and consistently working towards a carbon-neutral economy, and using any and all excess energy whenever and wherever to remove CO2 from the atmosphere and permanently sequester it until we're back to 1800s levels.
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I have to unfortunately largely agree with this. There's an illusion that technology and remedial actions will help here. Unfortunately none of these things are tested and, as we know from nuclear power, things which work great in theory always end up being more complex than expected. We should keep developing them (just like nuclear) but we have to build plans out of here that don't rely on any form of magic. Any extra we do get from geoengineering and new technologies will be more than welcome by our desc
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Until we master energy storage at large scales, we're going to have to have nuclear power OR a drastic drop in energy reliability in most places. I'm not keen on that because the idea of a expecting a technological civilization that's barely held together for 250 years so far (bits of it keep blowing up other bits of it) to a reliable custodian of nuclear waste for thousands of years seems very suspect.
On the other hand, I'm not philosophically opposed to using excess renewable energy to generate artificia
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Until we master energy storage at large scales, we're going to have to have nuclear power OR ...
Both. We're going to improve energy storage and have nuclear power.
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Nuclear - at least uranium-based nuclear plants - are a VERY short term solution. We more or less know where most accessible uranium is, and it's anticipated we'll run out of viable supplies by the end of the century. That means people born now will see it run out before they die of old age.
If we can get thorium working for us, we might have enough to go tens of thousands of years. Still not a 'forever' fuel, but I think that's probably long enough to justify kicking that can down the road and letting th
Uranium & Thorium [Re:Playing with insolation. (Score:2)
Nuclear - at least uranium-based nuclear plants - are a VERY short term solution. We more or less know where most accessible uranium is, and it's anticipated we'll run out of viable supplies by the end of the century.
Yep. In the very near term, we'll need spent fuel reprocessing, but in the longer term we'll need breeder reactors.
Both have problems which need to be dealt with.
That means people born now will see it run out before they die of old age.
If we can get thorium working for us, we might have enough to go tens of thousands of years. Still not a 'forever' fuel, but I think that's probably long enough to justify kicking that can down the road and letting the future deal with the problem.
Thorium does sound good.
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Until we master energy storage at large scales, we're going to have to have nuclear power OR a drastic drop in energy reliability in most places.
I used to argue like this. Then I didn't, but I kept hearing this, and I almost started "getting used to the fact".
But it's BS. Real facts tell a different story [www.br.de].
Germany is one of the countries that -- by some accident of politics -- rushed into abolishing nuclear power, and replaced it by coal and gas. Now that gas went mostly dry owing to geopolitics, we were told we can't stay warm without nuclear, even more coal, etc. But the facts: we've just had our first winter after the Russia's invasion of Ukraine
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Re: Playing with insolation is a bad idea (Score:2)
True. But the last winter was far from "hot, no heating necessary", and yet here we are. And there's a lot potential for improvement (I named some) that's nor related to nuclear or coal.
We have time to improve. The winters will get cooler, but we can also prepare better.
So, here we are: not at "no chance", not at "orders of magnitude apart", not at "ridiculous proposition", not at "summer child dreaming"-- we're at "if the winter is on the milder side of the spectrum, we're already doing it, with room to s
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Until we master energy storage at large scales, we're going to have to have nuclear power OR a drastic drop in energy reliability in most places.
Others said both, and I do think there's a space for nuclear. Much more important are fully interconnected grids. If the whole of America could be set up in one grid, a thing currently blocked mainly by politics, then times of low energy production would be much fewer and would have much greater availability during the dips.
Once we get to that level, I do think that having variability is actually important, at least expressed as variable pricing. There are lots of things ike air conditioning that could easi
Can we stop this nonsense? (Score:2)
Forget trying to block the Sun's rays or increasing cloud cover. There is a simple and easy way to combat this [youtube.com], but because it's so simple it won't be done.
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The real nonsense is that we are going to take control of the climate as well as every ecosystem and never again allow any change anywhere.
One small example,
https://www.opb.org/article/20... [opb.org]
The better owl must not win.
"Once And FOR ALL." (Score:2)
For a more practical take, try https://what-if.xkcd.com/162 [xkcd.com].
There are no easy solutions here (Score:2)
Looking for them only makes the catastrophe at the end worse and last longer.
WTF is this babbling about (Score:2)
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Clouds absorb infrared, this is true. But they absorb less than the ground, and they're better than the ground reflecting it as well as re-emitting more of what they do absorb to space. More clouds absolutely would mean a net reduction of heating for the planet.
Because of this, while it may be difficult to calculate the net effect precisely (and I suspect it's not)... it does not take a climatologist to understand that cloud cover is a good thing, at least for this simple part of the equation.
Where it gets
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Animal agriculture & fossil fuels (Score:3)
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I'm still not giving up meat, sorry dude.
Also, are you really sure that having fewer livestock around would lower temperatures? Has that been proved?
Re:Animal agriculture & fossil fuels (Score:4, Informative)
Cows fart, a LOT. And there's a lot of other negative ecological impacts from raising them, including but not limited to many farmers pumping them full of antibiotics and in turn breeding antibiotic-resistant bacteria. Beyond that, a lot of red meat in your diet is simply unhealthy for you.
I'm not giving up my filet mignon any time soon, but I was reducing beef consumption in my home even before the prices started to get ridiculous. My house is now responsible for a LOT more murdered chickens. 65 million years go, their ancestors were eating my ancestors, so I'm very OK with this outcome.
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You are 100% reasonable.
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Your argument is clearly false.
No one is asking for this, yet. (Score:2)
These things are in the first stage of being investigated, and we are still in the stage of asking, "Is this a good thing to do?". This research comes down on the 'possibly not' side, with a solid 'But more research' caveat.
We know what we should do, and that's to stop burning stuff. That isn't happening because burning stuff earns people money and makes people's lives more convenient.
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These things are in the first stage of being investigated, and we are still in the stage of asking, "Is this a good thing to do?".
Yeah, but how anyone thought that placing the most potent greenhouse gases in the atmosphere to cool things off is kind of odd.
This research comes down on the 'possibly not' side, with a solid 'But more research' caveat.
Always more research needed. Always.
We know what we should do, and that's to stop burning stuff. That isn't happening because burning stuff earns people money and makes people's lives more convenient.
People might consider also that "burning stuff" has a limited lifetime. We have to consider what happens after it becomes so expensive to extract and burn stuff that we either fold the tents and reduce the world to pre-industrial conditions, or further develop and deploy renewables like solar and wind.
slashdot is massively infiltrated by Davos (Score:2)
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I think you misspelled "Davros", because it would be extremely silly to accuse all of the ~11 000 citizens of a small town in Switzerland of duplicity.
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You don't know the Swiss, those devious central Europeans hiding in their mountaintop lairs above their chocolate mines.
Bastards, the lot of them!
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I think you misspelled "Davros", because it would be extremely silly to accuse all of the ~11 000 citizens of a small town in Switzerland of duplicity.
I've seen those bastards - they are sketchy AF.
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90% of the comments are dumb, but that means they're genuine.
What's sad is that the denialists have access to all the information they need to know they're being dumb, but they refuse to read it and claim it's all a globalist plot when the corporate globalists are the ones who created the fucking problem.
lol (Score:2)
So we can't do a technological solution because eclipses??
Oh well, I guess it's back to emoting and pretending that we are going to de-industrialize.
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So we can't do a technological solution because eclipses??
Oh well, I guess it's back to emoting and pretending that we are going to de-industrialize.
Pumping the most potent greenhouse gases into the atmosphere to cool off the earth is perhaps like having sex with your girlfriend so she stays a virgin. Might make you both feel good, but it did not work.
The problem with the technological solutions is threefold.
1. You have the denialists who say there isn't even a problem.
2. You have the Do something now, goddammit! people, who latch onto every proposal like manna from heaven.
3. You have people like me who know a little bit about the subject, the de
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Because: we. don't. know. enough. (Score:2)
Seriously. This kind of "oh, we discovered that ..." keeps coming out simply because someone finally gets around to asking the question.
Don't care why that is but it means Geo-engineering is foolish and dangerous.
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Seriously. This kind of "oh, we discovered that ..." keeps coming out simply because someone finally gets around to asking the question.
Don't care why that is but it means Geo-engineering is foolish and dangerous.
A thousand times this. We inadvertently geo-engineered the situation we are in now.
And the scope of the so called solutions will make things worse, as likely as not. What do we want - a thousand years of global acid rain? a runaway sequestration effect, combined with permanent red tides?
Umm... (Score:2)
Water vapor and clouds are the most potent greenhouse "gases" https://en.wikipedia.org/wiki/... [wikipedia.org]
So we are going to cool the earth by invoking more radiative forcing. Simply brilliant. Or simply idiotic.
It's not just about the greenhouse effect (Score:1)
Ocean acidification is a major problem as well, and simply blocking out sunlight without reducing atmospheric carbon will not help with that. (Well, it will help a bit because a warmer ocean dissolves more CO2, but the higher concentrations are what mostly drives it.) Indeed, if we start to think we can stop warming in such a way, and so reduce efforts to lower CO2 concentration, that would be a backward step.
Further, acidification is largely from dissolving CO2, so dealing with methane alone won't fix it.