China's green revolution
China's leaders say they want to clean up Chinese industry and invest in renewable low carbon technologies, but why? Is this about tackling global warming or does China just want to get a share of the booming clean energy market.
Justin Rowlatt talks Dr Shi Zhengrong founder of the world's biggest solar panel manufacturer, Suntech.
He also speaks to Daniel Foa, founder of FairKlima Capital who works with a local micro financing scheme to encourage investment in a novel low carbon technology - collecting bio-gas from pig waste which creates methane for a continuous supply of gas for home cooking.