The reason I said "net carbon captured" was to avoid the "cobra effect" of people releasing carbon deliberately so they can capture it, or of people using fossil fuel powered carbon capture that releases more than it captures. If they are paying high taxes on fossil fuels then it will quickly become unprofitable, so in that case it's not a serious problem.
Assuming they are not later burnt, growing trees qualifies as carbon capture. I now realize the tax would have to be on all forms of CO2 emissions, not just fossil fuels, otherwise the captured carbon would be re-burned.
But so far without a carbon tax there hasn't been much incentive to reduce CO2 release in absolute levels.
A gram of carbon saved is equivalent to a gram of carbon captured.
> This problem could be avoided by limiting applicants to countries with the fossil fuel tax + import tariffs, and judging purely on carbon recovered.
I am not sure how that's avoiding the problem at all?
Btw, how would you judge the brilliant idea of growing trees?