Thursday, December 08, 2016

"The climate has always changed"

The current stock response of the climate change denial lobby is this:

"We are not climate change deniers! Climate has always changed, it has been changing for billions of years! Therefore the current climate change that we are seeing has nothing to do with our CO2 emissions!"

This is one of their weakest arguments, refuted on two grounds.

First, they are saying that Earth average temperature is essentially unstable, and will vary greatly (chaotically even)  with any given natural input, be it large or small. In technical terms, they are saying that climate sensitivity is high. Their problem here is that in the technical debate about climate sensitivity, their advocates put an awful amount of effort into arguing that climate sensitivity is in fact low.

So they cannot have it both ways. Either climate sensitivity is high, or it is low. Either their technical experts are right, or their media mouthpieces are right. Which is it?

Secondly, they are also denying some or all of these facts: that the Earth has a greenhouse effect, or that CO2 is a greenhouse gas, or that we have changed the levels of CO2. All of which is to deny basic physical science.

So the argument "The climate has always changed" is an empty rhetorical device. It has no logical consistency, and no basis in science.

No comments: