Geo-engineering solutions like injecting dust into air are risky, but may become necessary if emissions cuts are insufficient to stave off catastrophic warming.

Climate scientist Ken Calderia of Carnegie Institution urged that research into the pros and cons of geo-engineering (climate change engineering) be prioritised.

"We need a climate engineering research and development plan, in addition to strong measures to reduce greenhouse gas emissions," said Caldeira, a faculty member of the Carnegie's Department of Global Ecology in Stanford, California.

He was testifying at an inquiry on geoengineering convened by the Innovation, Universities, Science and Skills Committee of the House of Commons.

"Prudence demands that 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," he said.

Climate engineering (or geoengineering) refers to controversial proposals to deliberately modify the Earth's environment on a large scale, primarily to counteract greenhouse warming, said a Carnegie release.

One scheme would cool the planet by injecting dust into the upper atmosphere to scatter incoming sunlight. Other possibilities include enhancing cloud cover over the oceans. Critics question the effectiveness of these schemes and worry that tampering with the Earth's systems would create as many problems as they solve.

But others warn that currently accelerating carbon emissions may push the planet's climate system to a tipping point, making drastic measures necessary to prevent an environmental calamity.