You can't tax carbon coming out of the ground in other countries. If I produce something and emit carbon in a foreign country, then import that thing into your

You can't tax carbon coming out of the ground in other countries. If I produce something and emit carbon in a foreign country, then import that thing into your country, you need to make sure that import gets taxed on the emitted carbon. So you need to estimate that emitted carbon. Your proposal only works if every single country worldwide agrees to tax carbon at the same rate, and effectively applies it.