The UK government is set to give the green light for experiments to dim sunlight to fight global warming, the Daily Mail reported. The green light is expected to come within weeks. Scientists are considering various methods to prevent runaway climate change, such as outdoor field trials including injecting aerosols into the atmosphere, and brightening clouds to reflect sunshine.
£50 million has reportedly been set aside by Aria, the Government’s advanced research and invention funding agency, for the projects. Prof Mark Symes, the programme director for Aria (Advanced Research and Invention Agency), explained that there would be “small controlled outdoor experiments on particular approaches.”
“We will be announcing who we have given funding to in a few weeks and when we do so we will be making clear when any outdoor experiments might be taking place,” he said.
“One of the missing pieces in this debate was physical data from the real world. Models can only tell us so much,” Symes added. “Everything we do is going to be safe by design. We’re absolutely committed to responsible research, including responsible outdoor research. We have strong requirements around the length of time experiments can run for and their reversibility and we won’t be funding the release of any toxic substances to the environment.”
Geoengineering projects seeking to change the climate artificially have often been criticised. Many have argued that these experiments could bring dangerous knock-on effects, and be an unhelpful distraction from lowering emissions.
However, the fact that carbon dioxide levels are not falling fast enough has alarmed scientists. They believe further action is needed to stop catastrophic warming.
Sunlight Reflection Methods (SRM) is a major area of research. This includes Stratospheric Aerosol Injection (SAI), during which tiny particles are released into the stratosphere to reflect sunlight. Marine Cloud Brightening (MCB) is considered to be another potential solution, wherein ships would spray sea-salt particles into the sky in an attempt to enhance the reflectivity of low-lying clouds.
Geoengineering ideas
Experts have found that in recent years, the clouds above shipping routes were far brighter than usual. They become more reflective due to pollution, which ends up bringing an overall dimming effect.
“If you inject small particles into clouds you can brighten them hence reflecting more sunlight back out to space,” Prof Jim Haywood, of Atmospheric Science, at the University of Exeter, said. “How do we know this could work? Well there are a couple of very strong pieces of evidence.”
Haywood added, “Ship emissions from the smoke stack into the marine environment lead to bright lines in clouds over the ocean. Then there was a volcanic eruption in Iceland in 2014 which spilled out a lot of sulphur dioxide. What this does is it brightens clouds and cools the planet. What we need to do is some form of field experiments.”
Another idea is seeding cirrus clouds to let more heat escape into space. The wispy high-altitude clouds trap heat by acting as a blanket.
“Every time you fly, sulphur, which is naturally present in jet fuel, is emitted into the lower most stratosphere causing a small cooling effect,” said Dr Sebastian Eastham, a senior lecturer in Sustainable Aviation at Imperial College London. “Similarly, aircraft contrails cause accidental cirrus cloud modification but in this case accidentally causing, rather than preventing or thinning, cirrus clouds.”
Eastham added, “This points to the fact that it’s theoretically possible (to cool the planet) with current day technology but there are many practical questions that would need to be answered before they could be done at scale.”
Experts hope that if their experiments are successful, they would be scaled up and then implemented within 10 years. Besides outdoor experiments, Aria is also set to fund new modelling studies, indoor tests, and climate monitoring. It will also gauge public attitudes to geoengineering.
