Some of the world's leading scientists say technology can help in the fight against climate change. If global temperatures continue to rise, we might need their solutions. They include mechanical trees that absorb carbon, machines that brighten clouds and a solar reactor that makes fuel from fresh air. The scientists say their inventions have been shown to work at small scale but would need massive investment to reduce the effect of our greenhouse gas emissions. Richard Bilton meets the scientists trying to save the world and investigates whether they can really make a difference. (Senderinfo)
