I would be really grateful if someone can summarize the details of how people project $12b in costs and explain the modeling. I know that a lot of work has bee

I would be really grateful if someone can summarize the details of how people project $12b in costs and explain the modeling. I know that a lot of work has been done into economic impacts of climate change / air quality, and I've been interested in knowing how people make, project and test these models for some time.