Apologies to cloud purists. While geoengineering the environment remains a controversial and hotly debated topic among climate scientists, a new tactic involving adding particles to marine clouds may be a promising strategy to fight global warming.
The idea, called “marine cloud brightening”, involves spraying saltwater into the air to make the clouds over the ocean brighter, enabling them to reflect more solar rays.
While still in the initial stages of testing, scientists hope that this tactic may serve as an effective, short-term measure to offset rising global temperatures. In addition, the further research into geoengineering—particularly involving aerosol manipulation—could help inform different and other successful methods to address climate change.
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,” Professor Thomas 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.’”
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.
“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?’”
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