Why don't I take a crack at that?
First off, cement is a powder. It's a finely ground powder, and cement only goes into concrete, which is sand, water, and gravel, at a 7% to 10% ratio. When we make cement, we produce approximately 750 kilograms of greenhouse gases per tonne of cement, but with only 7% tp 10% going into concrete, we're down to about 75 kilograms, which puts us very comparable to other building materials.
I would always say that you first have to understand what we're talking about: the difference between cement and concrete. There is no other market for cement other than concrete. You look at what it's going to be used for, and I would say that anything to do with having clean water would be worth the investment in concrete in order to treat that water. We shouldn't be having any sewage going into lakes and rivers that is untreated. I, like you, spent 10 years on city council so I have a very good understanding of that.