Could spraying particles into marine clouds help cool the planet?

From Eurekalert

Public Release: 25-Jul-2017

University of Washington

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 climate 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 climate models.”

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.

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?”

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 aerosol particles 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 clouds (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 test 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?'”


For more information, contact Wood at or 206-543-1203 and Ackerman at or 206-221-2767.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

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July 25, 2017 2:27 pm

With sun cycles 24-27 ushering in a new grand minimum, why would you want to cool the planet?

Reply to  visionar2013
July 25, 2017 3:28 pm

Because by cooling it the government will pay you money. The Titanic hit an iceberg at slow speed (it was not trying for a records crossing on a maiden voyage) and the boat count was based on its tonnage draft by maritime law, not the number of passengers. Nothing has changed. The business iceberg, climate change, is destroying baseload electrical systems and everything that depends on them, everywhere. The need to do something is based on CO2 tonnage, not whether CO2 is good for the passengers.
Governments do stuff by the ton because they can clip the ticket, not by the need.

Reply to  Geoff
July 25, 2017 8:53 pm

The government won’t pay “you” money for cooling the planet–the government will TAKE your money and give it to some brainwashed geo-engineering company to cool the planet.
By doing so, the government has defrauded the taxpayer AND rendered the planet less productive.
Such a government should be eliminated by whatever legal means possible–and the sooner the better.

Reply to  Geoff
July 26, 2017 7:00 am

In Titanic’s day, the purpose of life boats was to ferry passengers from a sinking ship to rescue vessels.

Reply to  visionar2013
July 25, 2017 9:14 pm

Right. Let’s not and say we did. “Oh, look. It’s cooling!”

July 25, 2017 2:28 pm

Taking dinosaurs off this island Trying to geoengineer global cooling is the worst idea in the long, sad history of bad ideas.
H/T Jeff Goldblum as Dr. Ian Malcolm in Jurassic Park: The Lost World.
Leave geoengineering in the realm of bad sci-fi movies…

Reply to  David Middleton
July 25, 2017 2:38 pm

I think it’s just the universities/professors/scientists trying their hardest to remain relevant…
….they know this is a nonstarter, but it looks and feels so good
I blame it on estrogen in our water…and toxoplasmosis

I Came I Saw I Left
Reply to  Latitude
July 25, 2017 3:35 pm

…and toxoplasmosis pus.syhats

Gunga Din
July 25, 2017 2:29 pm

Spray something on a Marine?
Get ready some unpleasantness!

Bryan A
July 25, 2017 2:31 pm

Could this action possibly cause rainfall over land in the form of Salt Water Rain?
If so it could bespoil natural watershed areas and turn drinking water supplies unusable. Not to mention the effect the (as)Salting water supplies would have on animals dependant on Fresh Water

Reply to  Bryan A
July 25, 2017 9:39 pm

Yeah — instead of vegetation turning brown from acid rain, it will turn brown from salty rain.

July 25, 2017 2:31 pm

possible emergency measures…………The proposal is now waiting on funding

July 25, 2017 2:34 pm

These clowns won’t be happy until we are in the throes of another ice age.

Rhoda R
Reply to  Kamikazedave
July 26, 2017 5:27 pm

Agreed – especially since we really DO NOT know what drives the climate to the degree that playing with stuff like this is letting a kid do brain surgery.

July 25, 2017 2:36 pm

Spraying particles into marine clouds, -stupid idea, particles would be washed away by frequent tropical rains.
I’ve just received six figure grant for fusibility study: “Prevention of catastrophic global warming by high reflectivity umbrellas to be carried whenever exposed to sunshine”

Tom Halla
July 25, 2017 2:39 pm

Hully gee! I was of the impression that the computer climate models did not deal with clouds well, with clouds having to be inserted into the models as a specification, not something the models simulate from basic inputs, like sunlight and GHG’s. So the models have improved enough that the group is now able to do engineering of the climate?

July 25, 2017 2:41 pm

The conference is to be held in Newry, ME.
Population: 329 (That’s all, really)
Newry is also the home of the Sunday River Ski Resort.
Otherwise, it is the very picture of “The Middle Of Nowhere”.
How very interesting. Perhaps the true purpose of this research project of spraying huge quantities of water all around is really to develop a better snow making gun, and get the Global Warming people to pay for it.

July 25, 2017 2:44 pm

We can run the envisioned sprayers off big marine diesels. Just the ticket.

Steve Case
July 25, 2017 2:48 pm

Geoengineering schemes without exception are totally stupid and utterly devoid of merit.

Randy in Ridgecrest
July 25, 2017 2:49 pm

So, they want to make a fog machine and use it in places that are…foggy?
Trillions of aerosol particles per second. Roughly that’s a kg of water per second.
i spent many fine days measuring optical turbulence on a path across “Laser Bay” on San Nicolas Island (U.S. Navy controlled Channel Island), I understand the attraction of doing sciency things on the beach and being pay for it.

July 25, 2017 3:01 pm

The main article illustration has been around for some years – IIRC.
Not sure if it was always to do ‘marine cloud brightening’ – per second paragraph.
Will this not also bring greater precipitation, leading to lowering ocean density, leading to more evaporation, and more precipitation, more evaporation in a runaway cycle?
Build Arks.
Build Arks NOW.
Also send millions so I can investigate Ark-building, especially in the Bahamas, Tahiti, nicer parts of Southern France, and Las Vegas.
Mods – the above is /sarc – and deliberately alarmist.
[Is there any other sort of alarmist?]
Likely Willis’s cloud feedback will stop the runaway effect dead in its tracks.

Reply to  Auto
July 25, 2017 3:30 pm

You remember correctly. 😉

July 25, 2017 3:09 pm

I always love these ideas. Essentially this is their argument:
“Humans are destroying the environment. We will fix it by destroying the environment.”
These ideas really assume that the earth is not resilient. In fact, nothing could be further from the truth. Leave a house abandoned and in a few years or less, nature will ruin the house. The planet can heal from anything we throw at it and in short order. (Of course, common sense dictates that this is relative to the damage done.) But environs assume that nature is as fragile as they are and think it needs saving from uneducated peons. No, the earth doesn’t need saving. It just needs us be relatively good stewards.

Reply to  alexwade
July 25, 2017 7:40 pm

Better idea, instead of cleaning up the earth, move to Mars and clean that up. Many of the people on this planet are truly insane.

Mick In The Hills
July 25, 2017 3:20 pm

Sounds feasible.
However, what consideration has gone into the effects on clouds precipitating?
Will salt water saturation render them less or more likely to produce rain?

Roger Knights
Reply to  Mick In The Hills
July 25, 2017 5:49 pm

A few harmless experiments will clarify the matter.

Reply to  Roger Knights
July 25, 2017 9:46 pm

Use silver iodide.

July 25, 2017 3:20 pm

So at the time when human society has reached its highest level of achievement and wellbeing, we are to spend a bottomless pit of taxpayer money in a fruitless attempt to return to the depths of the ice age.

Mike Smith
July 25, 2017 3:21 pm

My models show that launching a large number of highly reflective helium-filled Mylar balloons would be much more effective at cooling the planet.

Reply to  Mike Smith
July 26, 2017 2:14 pm

My model – working somewhat obscured by my greeeeed – shows that giving me billions (Pounds – not mere dollars – although do send them, too!) will serve to slow whatever you disagree with, with a certainty exceeding 99.99%.
Now, I am aware that there is, in my model, which has a cartoon duck related to Donald D, rolling about in a large vault full of cash, a possibility of
– some confirmation bias, and – in the adjustocene
– a little first-mover enrichment, but, hey – you can’t make whatever it is you want without a spot of enrichment in South London, focussed on wine-imbibing elderly(ish) ex-seafarers . . .
Oh – Mods – this IS, indeed, /Sarc: big time.
I know that y o u realised that full well, but one or two of our ‘Don’t Feed the Troll’ visitors may – probably will – need the help I offer for free.

July 25, 2017 3:23 pm

Interesting concept, less artificially inject more of the most potent greenhouse gas into the atmosphere to help cool the planet.

July 25, 2017 3:26 pm

Considering you can use salt as a weed killer this sounds like it will work out well.

July 25, 2017 3:28 pm

The very fundamental problem here is that increaseing so called greenhouse gases in the Earth’s atmosphere will increase the warming of the Earth’s surface caused by the radiant greenhouse effect. But the reality is that the radiant greenhouse effect has not been observed anywehre in the solar system including the Earth. The radiant greenhouse effect is science fiction. Hence the basis for this study is science fiction.

Reply to  willhaas
July 25, 2017 3:32 pm

Expectation of funding, in the current environment, is fantasy.

Reply to  willhaas
July 25, 2017 4:30 pm

Well, actually what you are saying is not true. The high temperature versus the low temperature will have substantial deviation today in the Arizona desert compared to Houston Texas, primarily because of the difference in the amount of water vapor in the atmosphere at each location.

Reply to  LT
July 25, 2017 6:09 pm

You are talking about the wet lapse rate which has nothing to do with the LWIR absorption properties of H2O The lapse rate is a function of the heat capacity of the atmosphere and gravity and the wet lapse rate in considerably lower than the dry lapse rate which is evidence that H2O has a net cooling effect.

Reply to  LT
July 25, 2017 6:41 pm

It is a forgone conclusion that without water vapor in the atmosphere the planet would be over 30 degrees cooler, not warmer. Go back to High School.

Reply to  LT
July 26, 2017 7:05 am

LT, static vs dynamic.
Static: If there was no water vapor in the air, the planet would be cooler.
Dynamic: When water evaporates, it removes heat from the surface and then transfers that heat high into the atmosphere where it is released through condensation. This cools the planet.

Reply to  LT
July 26, 2017 1:15 pm

LT, removing all the H2O in the atmosphere would lower the albedo and increase the natural lapse rate, either of which would cause a warmer Earth’s surface.

July 25, 2017 3:33 pm

This reminds of the similar scientific studies, CIA involved, proposing to dust the snow on the poles with black coal particles to prevent the dreaded cooling scientists were predicting in the 60s/70s.

Reply to  jake
July 25, 2017 7:44 pm

China and India are contributing more particulate to the atmosphere than they did during the 70s. Where’s the cooling effect?

Reply to  Mick
July 26, 2017 7:06 am

The rest of the developed world is contributing less.

Owen in GA
July 25, 2017 3:44 pm

If you were to spray salt water into the atmosphere, wouldn’t most of the salt fall back to the ocean surface when the water evaporates as it will almost entirely do? Some salt should stay in the atmosphere as ions until rained out, but I doubt much would. I don’t think we would be in danger of causing salt poisoning on the land from rainfall.
That said, it is still a bad idea to try to start the next glacial cycle any sooner than the sun and orbital influences are set to bring it on.

Reply to  Owen in GA
July 25, 2017 9:52 pm

I can see it now — just as windmill farms sprung up like mushrooms on land, so will islands of salt foggers float like flotsam over the seven seas.

July 25, 2017 3:50 pm

Is space cold or hot? There are no molecules in space so our common definitions of hot/cold/heat/energy don’t apply.
The temperatures of objects in space, e.g. the earth, moon, space station, mars, Venus, etc. are determined by the radiation flowing past them. In the case of the earth, the solar irradiance of 1,368 W/m^2 has a Stefan Boltzmann black body equivalent temperature of 394 K. That’s hot. Sort of.
But an object’s albedo reflects away some of that energy and reduces that temperature.
The earth’s albedo reflects away 30% of the sun’s 1,368 W/m^2 energy leaving 70% or 958 W/m^2 to “warm” the earth and at an S-B BB equivalent temperature of 361 K, 33 C colder than the earth with no atmosphere or albedo.
The earth’s albedo/atmosphere doesn’t keep the earth warm, it keeps the earth cool.
“The first design consideration for thermal control is insulation — to keep
heat in for warmth and to keep it out for cooling.”
“Here on Earth, environmental heat is transferred in the air primarily by
conduction (collisions between individual air molecules) and convection
(the circulation or bulk motion of air).”
Oops! WHAT?! Did they forget to mention RGHE “theory?” Global warming? Climate change? Bad scientists!
Oh, wait. These must be engineers who actually USE science
“This is why you can insulate your house basically using the air trapped
inside your insulation,” said Andrew Hong, an engineer (See!!) and thermal
control specialist at NASA’s Johnson Space Center. “Air is a poor
conductor of heat, and the fibers of home insulation that hold the air still
minimize convection.”
“”In space there is no air for conduction or convection,” he added. Space
is a radiation-dominated environment. Objects heat up by absorbing
sunlight and they cool off by emitting infrared energy, a form of
radiation which is invisible to the human eye.”
Uhh, that’s in SPACE NOT on EARTH where radiation rules.
“Without thermal controls, the temperature of the orbiting Space
Station’s Sun-facing side would soar to 250 degrees F (121 C), while
thermometers on the dark side would plunge to minus 250 degrees F
(-157 C). There might be a comfortable spot somewhere in the middle of
the Station, but searching for it wouldn’t be much fun!”
121 C plus 273 C = 394 K Ta-dahhh!!!!!
Shiny insulation keeps the ISS COOL!!!! Just like the earth’s albedo/atmosphere keeps the earth COOL!!! NOT hot like RGHE’s BOGUS “Theory.”

Michael Jankowski
July 25, 2017 3:53 pm

…”We are altering the climate already. It’s now a case of ‘the lesser of two evils’”…
Oh puhleeze.

July 25, 2017 4:09 pm

I’m glad I live in the sub-tropics then. When things start getting too cool down south as a result of their geo-engineering I’ll still be comfortable. Unless of course the additional water vapour actually does cause a runaway greenhouse effect…… Wow, just think, I could become one of their climate change refugees.

July 25, 2017 4:16 pm

Just as the planet enjoys a CO2-driven upsurge in crop production along comes the dead hand of another rent seeking swampy with a bat crazy idea.

Joel Snider
July 25, 2017 4:20 pm

Jeez. These people need to stop helping.

July 25, 2017 4:52 pm

“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.”
Here they go, assuming facts not in evidence.
Please give an example of CO2-related human activity that is currently altering the climate. Just one would be enough.
Don’t hold your breath waiting for someone to provide an example because there are no examples. These people are blowing smoke when they claim humans are changing the climate in an obvious way.

July 25, 2017 5:25 pm

They should just go forward. What they would discover is that clouds are heating, not cooling the planet. The bad thing is just, that first they would probably fail to procude any significant impact, and if not so, their interpretation will rather point to an accelerated global warming incidentally taking place at the same time, only pushing their efforts. So we might be heading for climate disaster after all – this time truly man made..

July 25, 2017 6:31 pm

Ummmmm, No!

July 25, 2017 6:48 pm

Why would we want to cool the planet.

Roger Graves
July 25, 2017 6:53 pm

“Water droplets can only condense on airborne particles, such as smoke, salt or human pollution.”
Not so. Water droplets will condense on electrically charged particles. This was known to particle physicists in the 1920’s – they used cloud chambers to detect charged particles. From the relevant Wikipedia article:
“A cloud chamber is a detector of ionizing radiation consisting of a sealed environment containing a supersaturated vapor of water or alcohol. An energetic charged particle (for example, an alpha or beta particle) interacts with the gaseous mixture by knocking electrons off gas molecules via electrostatic forces during collisions, resulting in a trail of ionized gas particles. The resulting ions act as condensation centers around which a mist-like trail of small droplets form if the gas mixture is at the point of condensation. These droplets are visible as a “cloud” track that persist for several seconds while the droplets fall through the vapor.”

Reply to  Roger Graves
July 25, 2017 10:06 pm

… hence, Svensmark’s theory of cosmic ray-induced condensation as solar wind decreases, which supposedly increases the earth’s albedo.

July 25, 2017 7:13 pm

There serious right?

July 25, 2017 8:11 pm

Fools Rush In

Michael S. Kelly
July 25, 2017 8:28 pm

A much more effective approach would be to buy thousands of 4’x8’x 1/8″ foot styrofoam boards, cover them with aluminum foil, and set them out in the ocean near the equator. Ocean albedo is about 0.06, while the aluminum would have an albedo of about 0.95 or better. It would be wicked cheap, and an excellent way to test climate models. So it will never be done.

July 25, 2017 8:42 pm

Humankind has an absolutely abysmal record when we try to “help” the environment. It never ends well, As we head into a phase of low solar output, doing something stupid like this idea could plunge us into a new ice age. Please stop this eggheaded nonsense now.

John from Europe
July 25, 2017 9:26 pm

These people should be put in jail, key thrown away and be given physics classes.

Jaakko Kateenkorva
July 25, 2017 10:08 pm

From Arctic circle perspective:
Marine salts are mostly chlorine, which is claimed to destroy the ozone layer. If it’s no longer an issue, disband UN Montreal protocol first.
The local climate should first recover enough from the last glaciation to enable vegan food cultivation and transport without fossil fuel. Currently the growing season is too short for cultivating corn.
In the meanwhile the offer, for paying more taxes to starve blind in cold, is declined.

July 25, 2017 10:30 pm

July 25, 2017 11:43 pm

Let’s try it. I’m sure nothing could go wrong.

July 26, 2017 5:13 am

This sort of idea is the source of unintended consequences. Rather than ameliorating the original problem (which isn’t one in this case), do something presumably to counteract its effects. And never stop to think of all the other things that might result from an ill-thought out idea.

July 26, 2017 6:16 am

Even better idea. What if we built fleets of millions of cargo ships that burned cheap fossil fuel bunker oil and released its high sulfur content in the form of sulfur dioxide, the world’s most powerful cloud brightening agent ( )? We could do massive geoengineering to increase the Earth’s albedo, and also conduct $12 trillion in international seaborne commerce as a side benefit. Wait, we’re already doing this? Brilliant! But the USEPA and MARPOL 2005 want us to stop — Why? Acid rain. It’s so confusing when environmentalists love and hate the same inanimate chemical element beyond all reason and sense of proportion all at the same time.

Roger Knights
Reply to  Ike Kiefer
July 26, 2017 10:11 am

The flaw in that is that the particles wouldn’t get into the upper atmosphere where they would be needed for geoengineering..

Reply to  Roger Knights
July 29, 2017 6:02 pm

Increasing albedo of surface and of tropospheric clouds is also proposed for geoengineering surface temperatures, and lower surface and low cloud albedo are blamed for increasing temps. That is not to say that it is not more effective to reflect solar radiation higher in the atmosphere.

Reply to  Roger Knights
July 29, 2017 6:04 pm

And if the sarcasm wasn’t clear, I see no need for such geoengineering in the first place.

July 26, 2017 7:08 am

My favorite piece of geo-engineering is to paint all cars white, in order to cool off cities.

Charles Perry
July 26, 2017 9:24 am

Reminds me of the Imminent Ice Age scare of the Seventies. At the time there was a serious proposal to cover all glaciers with black ash to reduce the earth’s albedo. Sometimes I think climate scares are basically about flattering us that we human beings are all-powerful.

Ed I
July 26, 2017 10:55 am

A decade or so ago I was involved with funding and then advising on a experiment that would track pesticide spray clouds in the coastal zone. We were using what was then state of the art LIDAR. The first two attempts we could not find the pesticide cloud. Initially it was assumed that it fell quickly to the earth. But that made no sense considering the particle size we knew was there. Since the prevailing wind was from the SE crossing the Atlantic Ocean and even our peninsula before reaching our experimental site I guess that what was blocking our particles was salt spray. After a bit of literature research and droplet size analysis the LIDAR operators quickly developed a algorithm to subtract out salt spray. It worked and we found and tracked our pesticide cloud. What amazed everyone was just how much salt spray we were talking about even though the Trade Winds had been light and we were almost a hundred miles from the opposite coast. So why do we need to spray more salt spray?

July 26, 2017 6:27 pm

Why would some humans think it is their right to “cool the planet ?
The warmer the planet the better . Antarctica case in point . Larger than the continental USA with less people in it than a Vegas casino .
People who want a cooler planet just need to move north or south and leave the rest of nature alone .

wayne Job
July 27, 2017 4:01 am

The last thing our planet needs is for some huge engineering project to try and change our temp climate our weather. Total madness.

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