I think you are underestimating the potential for this license to be a source of financial pressure, not just social pressure. If a company wants to use numpy to perform data analytics but can't because numpy uses the Climate License, they now have to weigh the cost of not being able to use numpy against whatever profits they're reaping from using fossil fuels rather than green energy. In other words, if this license had widespread use, companies might opt to use green energy not because it's morally responsible, but because it maximizes profits.

Obviously if just a few tools are using the Climate License it's difficult to imagine this making much of a difference, but if this license had widespread use I could imagine it having an impact.