The fight against global warming is expensive - are we getting value for money?
It's a quarter of a century since the Intergovernmental Panel on Climate Change was formed. On Friday it will release its latest report. In this programme we discuss the efforts that have already been made to prevent global warming and look at what can be done to mitigate its effects. We ask, do they offer good value? With contributions from Prof. Dieter Helm of Oxford University, risk expert Trevor Maynard from Lloyds of London and Guy Shrubsole of Friends of the Earth. Plus - Apple's mapping app comes under fire again, after drivers using the software were guided onto the taxiway of an airport in Alaska.