look at it — up eight fold, but the good news is the grey line is showing us the number of people who've died in those disasters has fallen threefold. that falling death rate shows warning people when bad weather is on the way can save lives. so, although we're seeing an increase in the number of disastrous events, the mortality rate is actually decreasing over the last five decades, and that's really down to the fact we've improved early warning systems, so we can notify people when an extreme event is about to happen, so that they can take contingency plans to save lives. but we need to go on improving those systems, because unless the world makes dramatic reductions to greenhouse gas emissions, scientists warn we can expect even more extreme weather events. justin rowlatt, bbc news.