> All the?

All the.

> We barely regulate CO2 at all.

Not sure who the "we" is, but many jurisdictions do regulate CO2 heavily. Not only immediate direct taxes, but subsidies to competitors, increased regulatory impositions and effective moratoriums on approvals, sovereign risk factors with many countries legislating and committing to CO2 phase out.

> If we started charging $100 per ton we'd see some massive changes.

Again not sure which we you are talking about, but lots of places have carbon taxes. They do make massive changes when they are priced to do so -- see, the EU. That was the point of my comment. I didn't argue markets don't respond to economic incentives, I clearly was agreeing they do. The effect has not been to solve climate change, it has been to move production offshore to markets that have much higher carbon emission intensity of production!

> And it's not hard to stop those loopholes.

And the fact that these not-hard-to-stop loopholes are not stopped still doesn't make you stop to think? The taxes aren't going to solve problems or pay for externalities, they are funding graft and corruption and stifling competition.