��ѿ��ý

Available for over a year

With all the bad news related to the climate is there actually some good news? Worldwide renewable capacity has now passed coal capacity for the first time. The story was reported across the world but is it the good news it first appears? What does the term ‘capacity’ actually mean? We've been speaking to the International Energy Agency to find out. Last week we looked at how good we are at spotting earth-bound asteroids but listeners were a bit puzzled by NASA’s claim that they had found 95% of all the asteroids over a kilometre. If they don’t know how many there are how can they have found 95% of them? Simon Maybin has been back to NASA for clarification. Tim Harford presents. Image credit: Shutterstock - solar panels and wind turbines