Regurgitating long debunked myths

IN his letter of November 16, Phillip Bratby regurgitates the longdebunked claim that water vapour is a far more important greenhouse gas than carbon dioxide (CO2). Briefly, water vapour amplifies the warming from CO2, acting in a positive feedback loop. CO2 causes the initial warming; warmer air holds more water vapour, which causes further warming and so on. But it’s CO2 that is the trigger for the water vapour feedback; without the initial warming from CO2, there’s no extra warming from water vapour.

Dr Bratby is also wrong when he claims that the IPCC says there is no evidence linking extreme weather events with a warming world.

In fact, the IPCC’s most recent Sixth Assessment Report contains a dedicated chapter on weather extremes and concludes: ‘It is an established fact that humaninduced greenhouse gas emissions have led to an increased frequency and/or intensity of some weather and climate extremes since preindustrial time, in particular for temperature extremes.’

Chris Snow Devon