Biden will do what he can, but without 60 votes in the sanat, he can only do so much. For example, Biden can get the EPA to push for better mileage for cars and make all new federal vehicles electric.
The greatest power that Biden / Dems have is budget voting. He might be able to get a bug-budget deal on green infrastructure as stated on his policy platform, but that will likely wait at least as long as the bill and impeachment are over for at least a month.
I'm sure Biden hasn't forgotten the climate, and as we head into the summer and fall fire and hurricane seasons, I expect a lot of pressure from Dems to accomplish something substantial if it hasn't happened by then.
Once Biden has achieved something substantial in the US, he will use that achievement as an example to pressure other nations to do the same.
I understand that every day counts, but I don't assume Biden isn't up to the task just because it's not announced yet. Remember, Bernie has already looked at the Bidens green infrastructure proposal and you can be sure that he will check out what he can legally enforce the Sanat on the budget vote.