I appreciate what you're saying -- that the end result of a Democratic majority Congress, in addition to a Democratic President -- is the same. However, I do think it's unfair not to acknowledge 2 points:

  - The executive isn't all-powerful
  - The Senate has the slimmest possible majority, with 2 caucusing members hesitant to do anything without the other party purely because of optics

Add to that:

  - Progressive wings of the Democratic party have come up with comprehensive climate plans
  - Democrats do tend to set emissions reductions goals, while Republican tend to undo those emission goals.

I think it's unfair to say that both sides are the same on this issue, basically because two members of the Senate Democratic caucus are indifferent on the issue, even though darn near 100% of the Republican party is opposed to any action on climate change.