"Unfortunately for mankind, there are now far too many of Homo colossus in the global population. And the damage is done. NASA climatologist James Hanson [sic] has claimed that the concentration of CO2 in the atmosphere should not be over 350 parts per million (ppm) in order to avoid calamitous climate shifts. But we are already at 400ppm and climbing."
January 1, 1970
https://en.wikiquote.org/wiki/Global_warming