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
- Live news updates from July 29: Musk countersues Twitter, ExxonMobil and Chevron hit record profitson July 28, 2022 at 3:54 pm
Elon Musk has countersued Twitter, the latest salvo in the row over whether or not the billionaire entrepreneur should be allowed to walk away from his $44bn deal to buy the social network. Details of ...
- What are the promises and perils of geoengineering?on July 27, 2022 at 5:00 pm
Cloud brightening, which could involve spraying salt into the air from ships to make reflective marine clouds, also has potential. “I’m certainly hoping that the world can ramp up climate action and ...
- Blocking Out The Sun: Viable Climate Countermeasure Or Absolute Madness?on July 26, 2022 at 5:00 pm
Other geoengineering techniques aim to help cool the Earth, too. Marine cloud brightening aims to also reflect more sunlight, but from a lower level of the atmosphere, while cloud thinning aims to ...
- Climate scientists have lost their mindson July 21, 2022 at 5:00 pm
Forget about rescuing the medical profession. Australia has a generation of chief health officers and doctors who can’t bring themselves to define a ‘woman’ for fear of the activist pitch-fork mob.
- Hercules Electric Marine Signs Agreement With Coach Marine Group to Supply Electric Propulsion Systems for Pontoon Boatson July 20, 2022 at 5:15 am
Hercules Electric Marine has reached an agreement with Coach Marine Group (CMG) to supply electric propulsion systems for pontoon boats.
- Using AI and machine learning to kickstart climate change fightbackon July 19, 2022 at 12:00 am
Fighting climate change with carbon capture or geoengineering means harnessing the power of AI and sophisticated data modelling ...
- A glimpse into Singapore’s sustainable light festival brightening Marina Bayon June 22, 2022 at 9:47 pm
An inflatable whale filled with recyclable plastic bottles and scraps highlights the plight of marine creatures that are struggling to survive in their increasingly polluted homes. An imaginary ...
- What is solar geoengineering?on December 5, 2021 at 12:38 am
The second, ‘marine cloud brightening’, would add aerosols—most often proposed are sea salts—to low-level clouds over ocean waters to increase their reflectivity. The report also said that ...
- Scientists Reveal Plan to Cool the World Through Geoengineeringon September 14, 2021 at 8:30 am
The project, first spotted by Interesting Engineering, focuses on a theoretical method of geoengineering known as "marine cloud brightening." The way it works is fairly straightforward ...
- Cost of cloud brightening for cooler planet revealedon December 16, 2014 at 5:35 am
Marine Cloud Brightening is a reversible geoengineering method proposed to mitigate rising global temperatures. It relies on propelling a fine mist of salt particles high into the atmosphere to ...
via Google News and Bing News