Heatwave: is this climate change?

The Saharan Bubble is blasting hot air across the European continent, breaking temperature records all over the place. But scientists are reluctant to link specific weather events to climate change, saying we can only be certain about long term trends. So when can we say for sure? We hear from Clare Nasir, a meteorologist with the Met Office, and Nick Cox, who's been measuring the Arctic climate since 1978.