* First, academic economists have basically ignored the topic. A survey of top economics journals found that, out of 77,000 total articles published, only 57 (0.074%) were about climate change.
* Many of the most cited papers have turned out to be crap, with basic calculation and data coding errors the authors have had to publish corrections for. Smith argues that this is partly because economists don't collaborate with other researchers much, especially natural sciences like climate change.
* The most important model for integrating climate change into macroeconomic analysis is the DICE model created by Richard Nordhaus. But the DICE model has big problems, the most important of which is that, due to discounting of future economic effects, it basically ignores the welfare of future generations. The DICE model also assumes that preventing climate change will be very expensive, and hasn't adjusted for recent technology advances on that front.
* Last, economists have been obsessed with carbon taxes, and haven't dealt with how politically unpopular they are, especially in international negotiations. This is, IMO, similar to how economists love to promote free trade, saying that the losers can be compensated via money from the overall economic gains, leaving everyone better off, and ignoring that this never, ever actually happens.
I'm in the camp that thinks that economists haven't earned a ton of credibility on the specific topic of climate change. Our best shot, IMO, is massive R&D efforts and CO2-removal geoengineering (especially wave-powered olivine weathering, as promoted by Project Vesta). Accompanied by crippling taxes on heavy emissions industries, but I think people will have an easier time accepting those if it's clear that governments are pursuing alternatives to taxes too.