Is it possible to quantify & cost the ideological obstruction to climate change?
Yes, it is possible to cost it. The range of costs could be estimated by taking the range of estimates of the marginal social cost of carbon (in €/tCO2e), and the range of estimates of the net excess amount of greenhouse gases [GHG] released due to delay (in tCO2e), and multiplying these together.

One starting point would be to ask how long it would have taken to get to zero net GHG if there had been international agreement in 1989, at the start of the IPCC, to put the world on track to tackle climate change (a deal that was killed by the USA, USSR, UK, Japan at the time), and what the total net emissions would have been on that trajectory, versus how they'll be if we achieve a 1.5&deg;C or 2&deg;C trajectory now.

I suspect no one's done it because it's not obvious what the value of the exercise would be: in the absence of a time machine, it doesn't really inform any decisions now.