> "Exxon knew of climate change in 1981, email says

Of course they new. Even if we exclude what Joseph Fourier (in 1824) [1] and Svante Arrhenius (in 1896) [2] wrote about carbon dioxide and the greenhouse effect, after [3] in 1967 and [4] in 1979, everybody who followed this branch of science, knew.

[1] https://en.wikipedia.org/wiki/Joseph_Fourier#Discovery_of_th...

[2] https://en.wikipedia.org/wiki/Svante_Arrhenius#Greenhouse_ef...

[3] https://en.wikipedia.org/wiki/Thermal_Equilibrium_of_the_Atm...

[4] https://en.wikipedia.org/wiki/Charney_Report