On this day, September 4 2006, the Royal Society (venerable Science outfit, 360ish years old) asked the American oil company Exxon to knock it off with the climate denial support.
https://royalsociety.org/policy/publications/2006/royal-society-exxonmobil/
On this day the atmospheric carbon dioxide level was 379.04 ppm Now it is 420ish- but see here for the latest.
Why this matters.
Exxon had been/has been an enormous source of climate denial, despite their own scientists saying in the 1970s that yes, indeed, global warming because of the burning of fossil fuels was going to be a serious thing. A bunch of scientists who don’t like hand-to-hand combat coming out and saying “stop right there thank you very much” was a big deal.
What happened next?
Exxon got sneakier about it, is all.