Warming The Planet Plan B

Earth needs a "Plan B" in the fight against global warming, in case efforts to curb greenhouse emissions fail or are inadequate, said an American scientist in testimony Monday to the British government.

Such a backup plan would probably need to involve climate engineering projects to deliberately counteract the effects of global warming. The engineering ideas that have been floated in recent years include injecting sunlight-blocking compounds into the upper atmosphere or building a gigantic structure in space to filter sunlight reaching Earth.

"Everybody keeps talking about tipping points and climate catastrophes," Stanford University climate researcher Ken Caldeira told Discovery News. "If you take the risk seriously, then you want to do two things: Reduce the chances of it happening, and if it does happen, then know what to do."


Caldeira addressed the U.K. Parliament's Innovation, Universities, Science and Skills Committee.

"Only fools find joy in the prospect of climate engineering," Caldeira said in his prepared testimony. "It's also foolish to think that risk of significant climate damage can be denied or wished away. Perhaps we can depend on the transcendent human capacity for self-sacrifice when faced with unprecedented, shared, long-term risk, and therefore can depend on future reductions in greenhouse gas emissions. But just in case, we'd better have a plan."

For years the idea of engineering the climate has been approached with great caution, since it involves a gigantic expense with unknown benefits and risks.

"Climate engineering is a very risky thing," Caldeira told Discovery News. "But increasing greenhouse gas emissions is also very risky."

There are cases in which the effects of our accidental climate engineering, via greenhouse gases, can only be reversed by some kind of engineering.

The plight of polar bears is one example. Thick perennial Arctic sea ice is disappearing fast, taking with it polar bear habitat. No amount of carbon emission reductions today will change that trend for decades or even centuries to come. Engineering may be the polar bear's only hope, Caldeira explained.

That said, engineering is not really a solution, said climate scientist David Victor, also at Stanford University.

"It's a tourniquet," Victor told Discovery News. "It's not a substitute for fixing the original wound. It might be part of a suite of actions."

In the end, said Caldeira, humanity faces three options with regards to global warming: 1) Reduce greenhouse gases drastically and immediately, 2) Adapt to a warmer planet, and 3) engineer the climate.

"I think there is a good chance we're going to end up doing a bit of all three of them," Caldeira said.