Technologies designed to control climate change by actively altering natural processes such as the Earth's absorption of solar radiation are generating a heated debate among scientists, environmentalists and policy makers.

Geoengineering to reduce global warming involves two main approaches:

  • Sucking carbon out of the atmosphere.
  • Blocking sunlight from reaching the Earth.

But the actual methods proposed for carrying those out can carry risks, says Eli Kintisch, author of Hack the Planet, a book about the technologies released last year.

"I felt that it was important not to try to sugar-coat how extreme some of these techniques are," he said to explain his choice of title.

CBC's The Current unpacked the debate from a variety of angles by speaking to:

  • Kintisch, who outlined the types of technologies being proposed.
  • Richard Owen, a business professor at the University of Exeter, who oversaw the governance of SPICE (stratospheric particle injection for climate engineering) – a geoengineering project designed to send particles high into the Earth's atmosphere, as volcanic eruptions do, scattering solar energy away from the surface.
  • Mike Childs, campaigns director for the environmental group Friends of the Earth, which petitioned against the SPICE project. He argues the technology could have "disastrous consequences on weather patterns around the world," risking people's lives and livelihoods. He said the technology is moving ahead without enough debate.
  • David Keith, a former University of Calgary researcher who is now a professor of public policy at Harvard University. He argues that geoengineering, by promising short-term climate results, should benefit the world's poorest, who are impacted first. Cutting carbon won't deliver such immediate results, he said, due to its long-lasting effects on the atmosphere. He added, "Just because something is a band-aid doesn't mean we shouldn't use it when there are people in trouble."