Could spraying particles into marine clouds help cool the planet?

Could spraying particles into marine clouds help cool the planet?
Ships crossing the Pacific Ocean emit particles into the clean air that create a seed for marine clouds. Credit: NASA

The idea of geoengineering, also known as climate engineering, is very controversial. But as greenhouse gases continue to accumulate in our atmosphere, scientists are beginning to look at possible emergency measures.

A new University of Washington study looks at the idea of marine cloud brightening, which a UW group is investigating as a promising strategy to offset global warming. The strategy would spray saltwater into the air to make marine clouds reflect more incoming solar rays.Small-scale tests of marine cloud brightening would also help answer scientific questions about clouds and aerosols, two UW atmospheric scientists say in a paper published in July in the journal Earth's Future. This dual goal for early-stage geoengineering tests would follow the U.S. National Academies of Sciences' 2015 recommendation that any tests of geoengineering also yield a scientific benefit.

"A major, unsolved question in science is: How much do aerosol particles cool the planet?," said lead author Rob Wood, a UW professor of atmospheric sciences. "A controlled test would measure the extent to which we are able to alter clouds, and test an important component of ."

Other co-authors are Thomas Ackerman, a UW professor of atmospheric sciences, Philip Rasch at the Department of Energy's Pacific Northwest National Laboratory and Kelly Wanser at the Ocean Conservancy.

The authors are part of a group that is proposing to spray saltwater over oceans to cause a small increase in the brightness of marine clouds and boost their capacity to reflect sunlight. Doing so could be a short-term measure to offset global warming in a possible future emergency situation. In the meantime, it could also further understanding of the climate system.

One of the biggest uncertainties in climate models is the clouds, which reflect sunlight in unpredictable ways. Water droplets can only condense on airborne particles, such as smoke, salt or human pollution. When the air contains more particles the same amount of moisture can form smaller droplets, which creates whiter, brighter, more reflective clouds. Climate scientists believe pollution since the Industrial Revolution has created brighter clouds that reflect more sunlight, offsetting the warming from greenhouse gases, which trap long-wave radiation. But they can't pin down the size of the effect or predict how much it might change in the future.

"Testing out marine cloud brightening would actually have some major benefits for addressing both questions," Wood said. "Can we perturb the clouds in this way, and are the climate models correctly representing the relationship between clouds and aerosols?"

Could spraying particles into marine clouds help cool the planet?
A conceptualized image of an unmanned, wind-powered, remotely controlled ship that could be used to implement cloud brightening. Credit: John MacNeill

The proposal is now waiting on funding from government or private donors. For several years, UW researchers have been working with a group of engineers in California's Bay Area to develop a nozzle that turns saltwater into tiny particles that could be sprayed high into the marine cloud layer. It's the first in a series of steps needed to implement the roughly three-year plan. The researchers propose to:

  • Produce a sprayer that is able to eject trillions of per second
  • Conduct initial lab tests of the sprayer (UW research scientist Dave Covert helped conduct wind-tunnel testing of a prototype nozzle in 2015 in the Bay Area)
  • Do preliminary outdoor tests in a coastal area that is fairly flat, relatively free of air pollution and prone to marine (the group is currently seeking funding for proposed coastal tests in Monterey Bay)
  • Move to small-scale offshore tests If tests were successful, people might someday decide whether to use a scaled-up version to create a small increase in the reflection of sunlight over large swaths of the world's oceans.

"We're talking about some kind of new world in terms of the ethical issues," Ackerman said. "But for climate, we're no longer in an era of 'do no harm.' We are altering the climate already. It's now a case of 'the lesser of two evils.'"

Ackerman will speak July 27 in Newry, Maine, at the first Gordon Research Conference on Climate Engineering about the proposed testing plan. Another speaker is the leader of a Harvard University test of an alternate proposal to spray reflective particles high in the atmosphere.

In addition to the paper on the scientific benefits of testing marine cloud brightening, a group of UW graduate students and professors published a recent paper on what specific measures might be feasible, ethical and scientifically useful for evaluating a cloud-brightening test. Authors include UW graduate students and faculty in philosophy, atmospheric science and civil engineering who were part of an interdisciplinary UW graduate course on geoengineering—among the first of its kind.

The class was taught last winter by Ackerman and Stephen Gardiner, a UW philosophy professor who wrote a book on the ethics of deliberately tinkering with the planet's atmosphere. Ackerman has since written an essay about the teaching experience. He believes the interdisciplinary approach is the right way to proceed with geoengineering.

"There's a science question about can we do it, but there's also an ethical question about should we do it, and a policy question about how would we do it," Ackerman said. "I'm an agnostic on this. I want to geoengineering and see if it works. But the whole time we're working on this, I think we need to still be asking ourselves: 'Should we do it?'"


Explore further

Clouds' response to pollution clarified with new climate analysis

More information: Robert Wood et al, Could geoengineering research help answer one of the biggest questions in climate science?, Earth's Future (2017). DOI: 10.1002/2017EF000601
Citation: Could spraying particles into marine clouds help cool the planet? (2017, July 25) retrieved 21 September 2019 from https://phys.org/news/2017-07-particles-marine-clouds-cool-planet.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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Jul 25, 2017
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Jul 25, 2017
We just need a lot of dust in the air.... (no special chemicals necessary)
Water builds up into raindrops around dust particles. IOW - builds up rain clouds clouds. These collect CO2 and then comes down.
(maybe stir up the Sahara a little, send up a little steam downstream)
This doesn't seem like rocket science.
It's how the earth has done it for millions (if not billions) of years...

Jul 25, 2017
Could spraying particles into marine clouds help cool the planet?


I dunno but you'd sure scare the conspiracy crowd, what with chemtrails and all. You'd freak them right the frick out.

You want to cool the biosphere, change the planetary albedo by painting all sky facing artificial surfaces, roofs, roadways and such, white.

Jul 25, 2017
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Jul 25, 2017
Oddly cloud-seeding experiments have been going on for 71 years and yet it hasn't been banned.

Jul 26, 2017
Again, note that, in the beginning, those who sought to deny the reality of chemtrails insisted that it is impossible to alter weather worldwide by a method like that, since the amount of chemical involved would be too big. Now, they accept that a not unusual number of ships could do it. And, since chemtrails are spewing chemical, it's likely they can have more of an effect. The chemical they seem to be spraying appears to be a form of water that has unusual thermal properties, among other things, a high thermal inertia, allowing it to hold more heat while being in conventional equilibrium with the atmosphere, until it releases it. Phys Org itself ran an article about a week or so ago about a new form of water being discovered, that could stay liquid at cold temperatures.
But, then, too, get a view into the nature of "scientists" when, to answer a situation, they think nothing of ruining people's quality of life with endless cloud cover.

Jul 26, 2017
Again, note that, in the beginning, those who sought to deny the reality of chemtrails insisted that it is impossible to alter weather worldwide by a method like that, since the amount of chemical involved would be too big. Now, they accept that a not unusual number of ships could do it. And, since chemtrails are spewing chemical, it's likely they can have more of an effect. The chemical they seem to be spraying appears to be a form of water that has unusual thermal properties, among other things, a high thermal inertia, allowing it to hold more heat while being in conventional equilibrium with the atmosphere, until it releases it. ...

Done all the time. It's called jet engine exhaust condensation.
CONtrails, not chemtrails...

Jul 27, 2017
BubbaNicholson:
Large reflective balloons in orbit around the equator would accomplish the same object with orders of magnitude less mass. L1 Lagrange Point balloons would also work. Reflecting away 1.7% of the solar illumination would instantly remedy global warming.


How many times do you have to be told that 1.7 million square miles of balloons is far too much to be realistic? Are you just another troll so obsessed with your teapot fantasy that you have to blurt it every time the subject comes up? What does it take for you sad nerds to stop polluting these discussions with delusion?

Jul 27, 2017
Chris_Reeve:
You want to turn climate change science into an election issue, then by all means go ahead and start your experiments. But, realize that you WILL lose that election.


Geoengineering isn't climate change science. It's not even science, it's engineering - and not even that, it's theoretical engineering: science fiction. Industrial science fiction.

In fact climate change science was an election issue in the last two presidential elections (and in the concurrent 4 Congressional elections), and the science that says humans are changing the climate with pollution won by millions of votes every time. It's only science denier (and their industrial sponsors) gerrymandering and other voter suppression that still retains power despite democracy.

Jul 27, 2017
Shootist:
You want to cool the biosphere, change the planetary albedo by painting all sky facing artificial surfaces, roofs, roadways and such, white.


Better to paint them with solar transformers (into usable heat and electricity). That doesn't just divert the sunlight but uses it to replace the petrofuels that make the accumulated extra sunlight a problem.

Jul 28, 2017
Shootist:
You want to cool the biosphere, change the planetary albedo by painting all sky facing artificial surfaces, roofs, roadways and such, white.


Better to paint them with solar transformers (into usable heat and electricity). That doesn't just divert the sunlight but uses it to replace the petrofuels that make the accumulated extra sunlight a problem.

increasing the efficiency of a single component of a system, doesn't always increase the efficiency of the entire system. Best to keep it simple...

Jul 28, 2017
Widening Gyre:
increasing the efficiency of a single component of a system, doesn't always increase the efficiency of the entire system. Best to keep it simple...


Replacing the complex, wasteful and harmful component of the system, that is the constant manufacture, consumption and emissions of petrofuels, with a simple component, that is the single manufacture, installation and recycling after 2-3 decades of solar panels, simplifies the system. Once PV paints are as widely available as simple white roof paint, that's extreme simplification that can scale to nearly all horizontal built surfaces.

Oversimplifying to just white paint is a stopgap measure that doesn't reduce the complexity and pollution upstream.

Jul 28, 2017
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