Professor Peter Thorne:

The warming impact, as assessed by the IPCC and as Dr. Rogelj and I said, is half a degree of the emissions. The methane is a flow. Therefore, if we were to reduce the methane burden by 20% across the board - the easier parts of methane are waste landfill and fossil fuels and we should be chasing those - after a period of time, about 20% of that half a degree would have gone.