Yes, but that's kind of unavoidable. Regulations make things more expensive.

On the other hand, if those regulations are actually effective (which I don't have the expertise to judge) and, for example, manage to delay by a little bit some negative climate effects, then it can still be cost-effective.

Climate change and pollution are expensive to the society. From increased natural disasters to public health issues, or disruption to international diplomacy (hence military costs), we always pay for it one way or another.

(It's just that it's difficult to make the actual computations, since the pollution from a single public contract is quite negligible compared to total human pollution, but the increase in costs is also quite negligible compared to the total cost of climate change)