We don't doubt this could be true, it's not important though

We’re not vouching for the truth of this but that it could be true is obvious enough:

The climate crisis will wipe at least 1% a year off the UK’s economy by 2045 if global temperatures are allowed to rise by 2C, the government has said.

It’s also not important even if it is true.

Or, to be entirely accurate, even if it is true it’s by no means the end of the matter. A change in the surrounding environment will reduce GDP. Seems a fair enough claim.

But what is the cost to GDP of not changing the surrounding environment? It is the balance of those two which determines what GDP will be as a result of climate change.

Of course, it’s entirely possible - wrong, but possible - to insist that we shouldn't consider GDP at all when deciding whether to ravage nature or not. But if that’s so then losing 1% of GDP isn’t a problem either.

All of the standard models of the economy used in climate change research assume, at the start, that the global economy will grow, from 1990 to 2100, by between 5 and 11 times as measured by GDP. That’s 500% to 1,100%. The difference between the extremes of those assumptions is that the higher growth comes from a globalised, largely capitalist and free market economy. The lower growth from a regionalised, more heavily regulated and, perhaps extreme, social democratic one. In the parlance of the SRES models, the difference between the A1 and B2 families of scenarios.

As it happens, the A1 with renewables (what is called A1T) produces that wondrous increase in wealth, the abolition globally of absolute poverty and also less climate change and emissions than that B2, a very much poorer future world.

It should be obvious that the difference between 500 and 1,100 is larger than 1%. Which is where the real calculations about the effects of climate change on and about GDP should be concentrated. Our very models which tell us that climate change is something we might want to turn our attention to also tell us what should be our underlying approach to matters economic as a whole. If we’re going to believe the models about climate change then we should also believe them about those matters economic as a whole.

So, globalised free market capitalism it is then and we continue the work on renewables alongside it. That way we get the richest projected future plus also deal with climate change - for yes, A1T does in fact deal with it.

This is also what we can call the no regrets policy. Even if climate change turns out to be a chimera we’ve still produced that as rich as possible world to leave to our descendants. So, why wouldn't we do this?