Even with Clinton as President, there will be no movement with climate change legislation, because at best the Senate will be controlled by a small majority of Democrats and the House will remain in the hands of the Republicans.
Because the Republicans are still a force to be reckoned with, it is likely the Senate will have a Republican majority in two years. With Clinton as President, the Democrats will have twelve consecutive years in the white house and as a result, are likely to lose the white house to the Republicans in 2020.
Meanwhile, Clinton will be investigated for various and sundry reasons which will distract from her agenda. Because of all of the aforementioned, I don't believe Clinton will be in a position to help with climate change or any other progressive cause.
OTOH, if Trump gets elected President this year, we are likely to see a Democrat controlled House and Senate in 2018. We are also likely to see a Democrat get elected President in 2020, and hopefully that individual will have a lot fewer skeletons in the closet. There are no guarantees of course, but given the scenario I've just laid out, this country will be in the best possible position to enact climate change and other legislation after the 2020 election.
This doesn't mean that I'm advocating voting for Trump and not voting for Clinton, but at this point, I just don't see how under the circumstances a Clinton presidency will advance the cause we hold dear. It is also why I'm finding it harder to pull the lever for Clinton on Tuesday, even though I probably will anyway.