Nothing can compete with renewable energy, says top climate scientist

Prof John Schellnhuber says that if countries implement their pledges made for Paris climate summit it will give huge boost to wind, tidal and solar power

Catastrophic global warming can be avoided with a deal at a crunch UN climate change summit in Paris this December because "ultimately nothing can compete with renewables", according to one of the world's most influential climate scientists.

Most countries have already made voluntary pledges to roll out clean energy and cut carbon emissions, and Prof John Schellnhuber said the best hope of making nations keep their promises was moral pressure.