In submitted testimony, Caldeira said while steep cuts in carbon emissions are essential to stabilizing global climate, there also needs to be a backup plan should emissions cuts be insufficient to stave off catastrophic warming.
"Prudence demands we consider what we might do in the face of unacceptable climate damage, which could occur despite our best efforts to rein in greenhouse gas emissions," Caldeira said.
He said climate engineering, or geoengineering, refers to controversial proposals to deliberately modify the Earth's environment to counteract greenhouse warming. One plan would cool the planet by injecting dust into the upper atmosphere to scatter incoming sunlight. Other possibilities include enhancing cloud cover over the oceans.
"Science is needed to address critical questions, among them: How effective would various climate engineering proposals be at achieving their climate goals? What unintended outcomes might result? How might these unintended outcomes affect both human and natural systems?" Caldeira asked. "Engineering is needed both to build deployable systems and to keep the science focused on what's technically feasible."
His testimony was heard Tuesday in the House of Commons.