What AGW damage curve do you prefer?
Attached is figure 9 from Keen (2023) "Loading the DICE Against Pensions".
This illustrates why there is so much to debate about future scenarios for AGW.
We know from the weight of scientific evidence that AGW is happening and is causing damage already, but there is much disagreement about how quickly the future damages from it will build up.
Much hangs on tipping points, estimates of when they will occur and how seriously the damages hit the global economy. The "logistic" curve example shown below anticipates tipping points having such impacts that total loss (ie nearly 100% of global GDP) occurs at some point in the next few decades, in the absence of sufficient actions to address AGW. But it's not the only curve in town ...
Most mainstream economists assume the gentle quadratic curve, which probably explains why many of them aren't overly worried about AGW. Some even suggest that AGW damage will only make a small dent in global GDP, so future generations can sort out AGW at some point in the future when they are richer than generations alive today.
But which curve do you think is the most plausible?
Personally, my view is the logistic (S-shaped) curve is the most plausible, based on tipping points being a real and dangerous threat. If tipping points are at all a meaningful concept, they have to follow a curve such as the logistic S-curve, despite the challenge of working out how to reflect probabilities of various timescales and steepness of accelerations.
In any case, as Ekins and Zenghelis point out, acting on sustainability (including AGW) might well be GDP-positive in itself. That makes acting a no-brainer in any case. The Precautionary Principle aligns with economically optimal pathways on this matter, as we try to prevent the rapid acceleration up the logistic curve.
FT "Lex in depth: how investors are underpricing climate risks" (17 Aug 2023):
Although it's quite old now, this video is still relevant and persuasive:
The Planetary CFO - working towards a sustainable World Balance Sheet.