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.’”
The Latest on: Marine cloud brightening
- Could marine cloud brightening help combat climate change?on September 14, 2019 at 10:04 pm
King opposes the release of stratospheric sulphates as anything but a last resort, because they might damage the tentative recovery of the ozone layer, but he is keener on a similar alternative: ...
- Scientists Suggest ‘Cloud Brightening’ To Halt Hurricaneson August 28, 2019 at 5:00 pm
Known as marine cloud brightening, or MCB, it’s one of many versions of geoengineering — the idea of counteracting global warming with some sort of technological counter-measure to cool the planet, ...
- Scientists ready to test cloud theoryon July 25, 2019 at 5:00 pm
The men – retired physicists, engineers, chemists and computer experts from some of Silicon Valley’s top tech companies – have been meeting four days a week for seven years in the Sunnyvale lab of the ...
- The desperate race to cool the ocean before it’s too lateon April 28, 2019 at 3:32 am
Instead the researchers homed in on the idea of marine cloud brightening—a form of solar geoengineering, in that it increases the planet’s reflectivity. Spraying tiny salt particles from seawater up ...
- How artificially brightened clouds could stop climate changeon February 26, 2019 at 6:18 am
Stratocumulus clouds also cool the ocean surface directly below. Proposals to make these clouds whiter – or “marine cloud brightening” – are amongst the more serious projects now being considered by ...
- How artificially brightened clouds could stop climate changeon February 25, 2019 at 4:00 pm
Hurricane seasons and El Niño, exacerbated by high sea temperatures, could be tamed by targeted cooling via marine cloud brightening. A PhD thesis from the University of Leeds in 2012 stated that ...
- To Have a Hope of Mitigating Climate Change, We'll Need to Tap the Oceanon October 6, 2018 at 11:09 am
Cloud brightening stays true to its name. In a feat of geoengineering, atmospheric scientists would spray water into clouds in hope of making clouds whiter, according to the Marine Cloud Brightening ...
- Scientist aims at ‘brightening clouds’ to protect Great Barrier Reefon July 16, 2018 at 6:11 am
However, an Australian oceanographer Daniel Harrison is developing a technology to protect it by ‘marine cloud brightening', as per the Chinese news agency Xinhua. Coral bleaching occurs when the ...
- Tech Industry Vets Fight Effects of Climate Changeon December 17, 2017 at 9:04 am
Photo: Marine Cloud Brightening Project Armand Neukermans (left) and Jack Foster (right) at work in the lab of the Marine Cloud Brightening Project Clouds, by reflecting sunlight, cool the land or sea ...
- Brightening clouds eyed as quick fix for global warmingon November 12, 2017 at 4:51 am
Harvard University is also conducting research, using philanthropic donations. At the University of Washington, a team of scientists has formed the Marine Cloud Brightening Project, which aims to drum ...
via Google News and Bing News