but they can't rule out a far bigger rise approaching two metres if the polar ice sheets collapse. the great ice sheets are already adding to the level of the sea, but this process may suddenly accelerate. scientists aren't sure, but the implications would be disastrous. india is now in the grip of flooding. higher seas would make it worse. the science has never been so clear that we can head off the worst of climate change, but not all of it, so we urgently need to get ready. let's speak now to dr greg flato, who is the vice chair of the ipcc group that authored the report. thank you forjoining us. just looking to the summary, the