For decades, scientists have been trying to invent ways to reduce global warming, with both average and extreme temperatures constantly on the rise. On Wednesday, a study published in the Science Advances journal proposes how one of these ideas could potentially work – an idea called “marine cloud brightening” (MCB), according to the National Oceanic and Atmosphere Administration (NOAA) of the USA.
The idea itself is not new – it was first proposed around 30 years ago – but what is new is the proposal for how to turn this theoretical geoengineering technique into reality, with a program of laboratory studies, field research, and cloud modelling.
“Interest in MCB is growing, but policymakers currently don’t have the information they need to reach decisions about if and when MCB should be deployed,” said study lead author Graham Feingold, a researcher with NOAA’s Chemical Sciences Laboratory, in a statement.
Basically, the plan involves a fleet of ships traversing the oceans, spraying seawater into the air, with the aim of thickening the clouds. The theory contends that the result would be a cooler atmosphere underneath the clouds, as well as more heat being reflected back out to space rather than absorbed into Earth’s atmosphere.
Theoretically, according to NOAA, water vapour would collect on the salt particles contained in the seawater, thus making the clouds larger, and longer-lasting.
Scientists are under no illusions as to the complexity of the endeavour. “We would have to get the right-sized particles into receptive clouds at the right times of day and seasons, and over large enough areas to shade large areas of ocean,” said Feingold. “It’s a major challenge.”
Perhaps surprisingly, the process already exists and has been proven to work on a small scale. The challenge these scientists are proposing to take on is about supersizing it to a global scale.
But others concerned that it might not be such a good idea to start tinkering with the processes that sustain life on this planet.
Kevin Trenberth, a scientist at the US National Center for Atmospheric research – which was not involved in the study – warned that it could have terrible unforeseen circumstances, and did little to address the root cause of the problem.
“I believe that it is possible to brighten clouds but the consequences of that are far from clear,” he said, adding that it could “change the patterns of weather”.
He also suggested that time and money could perhaps be better spent on other ideas. “They do not address the problem of global warming. Even if the mechanism worked, it would not reduce carbon dioxide and the cause of global warming,” he said.
The study also didn’t address the social, ethical, ecological, or governance aspects of MCB, focusing only on the science. Feingold acknowledged this and stressed that decisions relating to deployment of MCB would rest with elected politicians.
“With MCB, some will benefit, while others will suffer.”
