The problem is that they can’t just talk about climate problems they need to take action. And since the Democratic party isn’t going to support mass-executions of industry executives and billionaires, they’d have to talk about incremental changes. I’m not sure how they sell something like “we forecast that these new regulations will result in a 1 degree average temperature reduction over the next 4 years” (which would be huge). And that’s imagining that the party as a whole is able to agree on something hard enough to shove it past the Republicans.