Liz Truss, the new environment secretary has taken to the media to flaunt her green credentials.
Environment Secretary Elizabeth Truss “fully agrees that climate change is happening”, saying evidence on the issue – like the extreme weather events that battered the Westcountry last year – is very strong.
Ms Truss, whose department is responsible for ensuring the country adapts to the impacts of climate change, said she agreed with Prime Minister David Cameron in drawing a link between global warming and extreme weather events such as the winter storms that swamped the Somerset Levels, severed the main rail link at Dawlish and caused the region millions of pounds of damage in January and February 2014, from which many people are still recovering.
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In her interview with House magazine, Ms Truss said she was briefed by both the Environment Department’s (Defra) chief scientist Prof Ian Boyd and the Government’s chief scientist Sir Mark Walport shortly after taking the role.
She told the magazine: “I fully agree that climate change is happening. I think the evidence is very strong, but this department’s role is making sure we adapt to climate change and that’s taken into account in all our modelling.
This is worrying. Regarding "climate change", by which we must assume she means "manmade climate change", to demonstrate that this is happening it is necessary to show that the changes seen are out of the ordinary. Mark Walport agrees that this has not been shown for temperature changes - he conceded this point in answer to my question after his Glasgow lecture. I am reasonably sure that he would concede that we haven't demonstrated that any other features of the climate have changed in a statistically significant way either.
He does argue that the fact that several features of the climate have changed in a direction that suggests warming provides strong support for the idea of manmade climate change, but this seems wrong to me. For example, melting Arctic sea ice is supposedly a function of temperature, but we already know that the temperature rise is not significant, so demonstrating that Arctic sea ice is moving in a warming direction (with such a short record, showing it is in itself significant is out of the question) does not provide any extra evidence. And of course the fact that the Antarctic ice is growing points in the opposite direction anyway.
We can follow this same line of reasoning with, say, atmospheric water vapour. Yes this has gone up in response to higher temperatures (I believe), but no, not in a way that is out of the ordinary (I assume). Indeed it is interesting to consider the question of whether a non-statistically significant temperature rise could ever produce a statistically significant change in atmospheric water vapour.
When it comes to extreme weather it's the same thing. The Met Office report on the winter floods concluded that it was not possible to link them to mankind (Julia Slingo's attempts to misrepresent the report's contents notwithstanding). The storms, as far as we can see, were not very different to 1929/30.
So how is Truss coming away with an idea that there is "very strong" evidence that floods are being affected by climate change? What is she being told by Walport and Boyd?
We understand that carbon dioxide is a greenhouse gas, and might be expected to affect the climate, but this is not the same thing as saying that there is evidence that the climate has been affected by it. Does everybody concerned understand that there is no evidence that mankind is affecting the climate until we have demonstrated that the climate is is actually doing something out of the ordinary?