The UN-backed Science Based Targets initiative (SBTi), whichcertifies whether a company is on track to help limit global heatingto under 1.5°C, has bought into the idea that "carbon offsets" arevalid methods for curbing global heating.

The organization's staff condemn the plan and say it is not in factbased on science.

I've said for many years that we cannot trust a company to achieve thegoal, because it is easy to set upbogus offsets that won't really reduce emissions but only pretend to.

For similar reasons, a "carbon market" would be easy to game andtherefore to render ineffective. It appeals to the worshipers of theInvisible Hand.

By contrast, a carbon tax really would pressure companies to emit less greenhouse gas.