In recent weeks, several of the largest and most profitable American companies have introduced elaborate plans to combat climate change. So why are they doing it now? And just how meaningful are their plans? Guest: Andrew Ross Sorkin, a financial columnist for The New York Times. For more information on today’s episode, visit nytimes.com/thedaily.  Background reading: Laurence D. Fink, the founder of the world’s largest asset management company, sparked the shift toward climate-focused corporate policies in his annual letter to C.E.O.’s. Here’s what the letter said, and why it matters.Protecting the environment and tackling climate change have climbed the list of Americans’ political priorities this year as economic concerns have faded. But the issue is as partisan as ever.