The numbers in climate science really are quite amazing
A couple of days back we noted that the WWF presented us all with some truly remarkable numbers. Or rather, in their report about the costs of climate change, didn’t present the numbers which mattered:
We’re fine so far. They also say that higher emissions will cause more damage than lower. We’re fine with that as a logical assumption, something internal to the case being built. Then they say that higher emissions will cause damage to ecosystem services, these damages will lead to a reduction of GDP from what it would be in the absence of those emissions/damages. All of this is equally fine as a chain of logic. Sure, it may or may not be true but it’s logically valid.
Then they do something absurd. Remember that SSP5 gives higher GDP growth in the first place. That’s the bit they don’t account for. The thing they never do tell us is whether that final, net, outcome of more growth and more emissions is higher or lower than the slower growth and no emissions damage pathway.
This intrigued sufficiently that we’ve carried on chasing them for an answer. Just to recapitulate what we’d all like to know. Faster economic growth, with emissions and damages, leaves us better off or not than slower economic growth without emissions and damages? That is, after all, the information we need to be able to make a decision - assuming that we’re using being better off economically as our tie breaker on the decision.
We’ve asked this in the following format:
1) Using SSP5, deducting the damages from emissions caused problems with ecosystem services, what is global GDP in 2050? Or, if you prefer, global per capita GDP?
2) Using SSP1, not suffering those damages to ecosystem services as a result of emissions, what is global GDP in 2050? Or, if you prefer, global per capita GDP?
Our own assumption is that this must already have been calculated. For how can anyone claim losses in GDP if it hasn’t been? After 72 hours since we first started asking the response is, so far, this:
This query is straightforward but is not trivial to calculate.
They don’t in fact know. Yet not knowing is good enough to claim damages? This is not a recommendation for how people do climate change science these days, is it?