Suppose a totally new chemical compound is invented. Call it Pl.
The use of Pl generates no additional greenhouse gases. Quite the contrary. Adding Pl to power sources doubles the fuel efficiency of factories, air conditioners, heaters, and cars, trucks, boats and airplanes. Pl is priced low enough to make worthwhile its widespread use both commercially and residentially. As a result of the near-universal use of Pl, greenhouse-gas emissions plummet.
FYI, these emissions don’t fall fully to half of their pre-Pl levels, because the lower cost of powering factories, automobiles, etc., will lead to greater use than before of these things. But fall these emissions nevertheless do – and significantly, we can legitimately assume. Therefore, Pl‘s use means that we humans have even more factory outputs and greater access to other goods and services that, without Pl, would have been too costly to produce.
But there’s a downside: breathing in Pl in concentrations generated by its widespread use entails a 0.01-percent risk of contracting a previously non-existent and usually fatal lung disease. If contracted, this lung disease shaves, on average, five years off of each of its victims’ lives.
Here are some non-rhetorical questions:
(1) Is Pl a pollutant?
(2) Should Pl‘s use be prohibited, or at least taxed so that its use is dramatically reduced?
(3) Should Pl‘s inventors, producers, and promoters be criticized as enemies of humanity and despoilers of the earth?
(4 – and most importantly) Is Pl‘s use (as described above) excessive?