Climate change is a threat not just to the environment, but to people. And it's the poorest people who are most exposed. Tens of millions have been lifted out of poverty in the last 15 years, but more than one billion people still live in absolute poverty on less than $1.25 a day. Climate change also presents a growing danger to Britain. Flooding is the greatest threat to the UK from climate change, with up to 3.6 million people at risk by the middle of the century. The 2007 floods in Britain were a powerful reminder that, even in developed countries, climate change is national security issue. I agree with Pope Francis.