The mathematicians, physicists, and chemists working for these companies are the smartest in the world. Of course they knew. Odds are, they were the first to know, long, long before anyone even thought to be concerned.

And, frankly, when they first figured it out, back in 18whenever, it might not have been a big deal, considering the scale of things— until it really did start becoming a problem with urban air becoming unbreathable due to factory pollution from coal burning. Tech improvements staved these concerns off. Fuel your factory with oil instead! With electricity! But it all still required coal or oil at the power plant until we invented nuclear power.

Then the mass-produced ICE came along and the explosion of car ownership, and that really changed everything. And city planners like Robert Moses and his acolytes. Visions of distant cities connected by vast highway systems and cities themselves, intertwined with spaghetti-like structures invading once densely-populated, walkable cities, displacing and alienating everyone living there— all built on and fueled by a dizzying array of environmentally-devastating petrochemicals.

Oh, they certainly knew all along. They just believed that they could outlive the consequences and live fat cat lives off of the profits for generations. And for the most part, they were right.