I dare say the IPCC knows better than both Econlib and Nordhaus. There isn't much of an analysis here. They ignore the most obvious huge cost: the risk of reaching the tipping-point after which global warming would be unstoppable. They ignore the positive externalities of climate action, which are plenty in themselves. They ignore the fact that it is not possible to not act now and then suddenly put on the brakes on warming when we reach whatever target they deem appropriate.
1. https://foreignpolicy.com/2018/12/06/the-nobel-prize-for-cli...