A prominent Canadian scientist says it's time for the international community to start studying the use of global "sun blocks" as a way to fight climate change.
Sending particles into the atmosphere to block some of the sun's rays and reduce global warming is fast and cheap, and it could just be a matter of time before some country tries it without regard for the rest of the planet, said David Keith in an opinion paper published Wednesday in the prestigious British journal Nature.
"The risks of not doing any serious research, not beginning to build the tools of governance, are bigger than the risks of doing it," he said.
"We should admit that at some level, we're in the gardening business with the planet and think about doing a good job and not a lousy job."
Proponents suggest so-called "geoengineering" would probably take effect much more quickly than cutting emissions and at a fraction of the price. They also point out that years of international debate on emissions has produced almost no results and opening a high-altitude chemical parasol may soon be the only way to keep global warming at manageable levels.
"Solar-radiation management may be the only human response that can fend off rapid and high-consequence climate impacts," wrote Keith, who holds the Canada Research Chair in Energy and the Environment at the University of Calgary.
Keith acknowledges the approach is no substitute for emissions cuts. It would also affect some countries differently than others, creating winners and losers.
"Some areas would be more protected from temperature changes."
Geoengineering would lead to less precipitation and less evaporation. It could also weaken monsoon rains and winds.
But he warns that geoengineering is so simple and inexpensive that unless countries start talking about it, someone's likely to go it alone. Any country, big or small, could simply contract the services needed to salt the air with any one of a number of sun-blocking chemicals that would change the entire globe.
"Like it or not, the power to do this exists," said Keith. "We need to think about how we manage that."
Keith compares geoengineering to nuclear weapons, another technology with potential global effects that has been managed through international agreements.
"It's not been pretty, there's been lots of uglinesses and lots of uncertainties, but the reality is we have more or less controlled those weapons so far."
Andrew Weaver, one of Canada's top climate scientists, called Keith's paper an important addition to the debate.
"The approach he's talking about is a very balanced approach that I think we need to explore," said Weaver, a University of Victoria professor and one of the authors of the UN's Intergovernmental Panel on Climate Change report.
Studying geoengineering would at least allow governments to judge its utility, Weaver said.
"It's really important to inform policy with sound science and right now, that science doesn't exist in this area."
Weaver agreed with Keith that geoengineering wouldn't solve all the problems with high atmospheric carbon, such as ocean acidification. And he echoes the point that it shouldn't reduce the urgency of cutting emissions.
"I'm absolutely dead opposed to going down that route unless it's coupled with a very strong mitigation strategy and a very strong adaptation strategy."
Keith said countries such as Germany and the United States are already looking into geoengineering, but Canada is nowhere to be found.