I’m curious as to why you think it’s a catastrophic mistake.
The Paris agreements were heavily criticized by many climate scientists when signed; they were called “kicking the can down the road” because they did so little to address the actual problem of climate change.
But for some climate activists, the accord was an exercise in empty, feel-good promise making. For example, a group of climate scientists recently submitted a letter to The Independent calling the agreement “false hope” and full of “deadly flaws.” They cited the fact that the CO2 reduction commitments in the agreement don’t kick in until 2020. By that time, the scientists argue, so much more CO2 will have been pumped into the atmosphere that we may already be locked into warming pushing us above the 2 degree line.
So, the agreement (nor the US disavowal) does not seem to change the risk the world is exposed to vis a vis climate change. And to my knowledge, no pro-Agreement individual has been able to articulate HOW Paris actually addresses climate change directly. (There are lots of indirect statements floating around, but as soon as a politicians starts bemoaning a “lack of leadership”, it generally means that they don’t have a better answer to the question.)
So, how is it a mistake, especially considering that there’s nothing the prevents any nation, in or out of the agreement, from perusing renewables?