Biden will be doing what he can but without 60 votes in the sanate there is only so much he can do. For example Biden can get the EPA to push for better mileage on cars and get all new federal vehicles to be electric.
The biggest power Biden/dems have is budget reconciliation. He might be able to pass some big budget green infrastructure deal as stated in his policy platform but that is likely waiting at least until the covid relief bill and impeachment are over so at least a month.
I’m sure Biden has not forgotten about climate and as we move into summer&fall fire and hurricane seasons I anticipate a big push from Dems to get something substantial passed if it hasn’t been by then.
Once Biden has passed something substantial in the US he will use that achievement as an example to pressure other nations to do the same.
I understand every day counts but don’t assume Biden isn’t up to the task just because it isn’t announced yet, remember Bernie has already looked into Bidens green infrastructure proposal and you can be sure he is going to be looking at what he can legally push through the sanate in budget reconciliation.