On global average, human addition is dwarfed by the natural and its variation.

With the caveat that open-air nuke tests are dirty. Back in the bad old days before the 1963 test ban treaty, background from nuke tests hit 7 % of natural background (and climbing - meaning that if we'd kept up atmospheric nuke tests at the same rate it would have stabilised considerably above 7 % of natural background).

- Jake

Friends come and go. Enemies accumulate.