Many scientists think his goal of zeroing out greenhouse gas emissions by 2050 is technically possible and economically affordable. The politics are another story.
With Democrats poised to take control of both houses of Congress, Biden's opportunities to tackle climate change and other major environmental problems have greatly expanded. But given the closely divided Senate, the question is by how much.
Even if Democrats win the White House and the Senate in 2020, effectively combating climate change might require the elimination of the Senate filibuster.
