Waterloo Region Record
Greg Mercer
Wednesday, August 31, 2011

WATERLOO — It sounds like something out of science fiction — shooting massive clouds of black carbon into the atmosphere to block out the sun and cool down the planet.

But the research behind so-called solar radiation management is very real, even if it may be many years before countries seriously consider slowing climate change by essentially mimicking volcanic eruptions.

That’s where scientists like Stanford University’s Ben Kravitz come in. He says it’s important we figure out now what manufactured sun shields would mean for the planet, because that kind of atmospheric tinkering had better be done right.

“We only have one atmosphere, and we don’t want to do this until we’re pretty sure we know what we’re doing,” he said. “We’re talking about a pretty big interference with the climate system … in terms of the science, there’s still plenty to do.”

Kravitz’s area of expertise is a field of study called geo-engineering, and specifically looking at aerosols that absorb or deflect the sun.

Although scientists have talked for decades about cooling down the planet using planes, artillery and balloons that inject materials like sulphur, dust or tiny metal flakes into the atmosphere, the science of geo-engineering is still in its infancy.

“In the very early days of this discussion at the international level, it’s already been very contentious.”

And it’s a highly contentious subject. Kravitz will speak about it at a lunch seminar Thursday at the University of Waterloo’s Interdisciplinary Centre on Climate Change.

Researchers like Kravitz have long looked at large volcanic eruptions to better understand how those historic events have changed our atmosphere and dropped temperatures around the planet.

“That’s where the idea comes from. We want to sort of mimic a sort of permanent volcanic eruption,” he said.

But deliberately changing our atmosphere by releasing tonnes of sunlight-shielding material would have its drawbacks — namely the potential for drought and rapid swings in the planet’s temperature. Kravitz says it’s not even clear at this point if we should do it, and scientists are limited to experimenting with digital climate change models.

“As of right now, we don’t know what it would do. There’s an ongoing debate about that,” he said. “But we need to study every available option.”

Kravitz has focused his recent work on whether black carbon, which is good at absorbing sunlight, could be suitable material for climate engineering. But he hasn’t studied the impact of what it would mean for people’s health, he said.

He admits climate engineering is, at first blush, a radical idea. But as a scientist on a warming planet, it needs to be studied as an option to counter the dangers of climate change, he said.

“It’s pretty scary. A lot of people have expressed that they hope we don’t have to use it,” he said. “But the climate change problem is pretty severe, and likely getting worse, so we may need some kind of emergency measure.”

Then there’s the big issue of who decides whether humans should try such a dramatic intervention in our climate, said Jason Blackstock, The Centre for International Governance Innovation senior fellow who organized the talk.

“We’re talking about something that could impact the lives of literally billions of people around the world. Who gets to make the decisions around these technologies?” he said.

Given all the discord around climate change itself, it’s certain we’re a long way from any sort of agreement on such a developing science as geo-engineering.

“These are very new ideas and questions of how they will get used are the more important ones for society,” Blackstock said. “In the very early days of this discussion at the international level, it’s already been very contentious.”