At this point, I think we should be willing to call out these ideas for being unhelpful distractions from what will really be needed to combat climate change. A

At this point, I think we should be willing to call out these ideas for being unhelpful distractions from what will really be needed to combat climate change. As you point out, the math just doesn't add up. Photovoltaics on car roofs is just a dumb idea, beyond perhaps some novelty charging of accessories (e.g. running the A/C on hot, sunny days). There was a good article recently (maybe it was Washington Post, can't remember), about what will really be needed to combat climate change, and I thought it was pretty great. Did a great job of highlighting the things to focus on that can actually be built fast enough (e.g. overbuilding renewables generation, upgrading electrical grids, "electrify everything", etc.) vs what are just distractions that are too small (or slow to build out) to make a dent in what actually needs to happen. You could perhaps argue with the author on some of the details around the edges, but the main points were pretty unassailable in my opinion. These proposals that will never amount to more than a drop in the ocean aren't worth wasting time on, and worse than that, they can make people "feel" like they're doing something valuable when they really aren't (see: most plastics recycling).