The democratic party is a coalition party ranging from the neoliberals all the way to anarchists and everything in between. In general, the people that are nominated are controlled by the party establishment but the people that vote range from a variety of left biases. After all, the Democrats are the only decent conservative party left in this country.

The Democrat's establishment is what matters in these conversations, and yes they refuse to acknowledge that the root causes of climate change is late stage neoliberal capitalism.

What exactly is a solution to that?

They don't deny it but exaggerate how much they care in order to get that sweet, sweet social credit - much like conservatives and "traditional values". The ones that play this game the best are the ones that end up in power.