For these people, even if (a big if!) there would be a global consensus, then they would not approve significant cuts to the industry and consumption in order to prevent the limited effect that we're seeing now. The world was a much poorer place in absolute numbers, and wellbeing was directly linked to physical goods unlike the digital economy we have now, so even with perfect foresight, the big priorities of that era would still be increasing agriculture (through mass use of fossil fuels!) to feed people and increasing industry (through mass use of fossil fuels!) to reduce global poverty. The Green Revolution and economic changes of 1965-1985 were an enormous boon to humanity, and sacrificing THAT to slow down climate change would not be a good deal for us.
And of course, unilateral sacrifices make even less sense. At the height of the Cold war, neither the west nor the USSR could agree to simply restrict their industry while the other would do nothing, because then you suffer all the drawbacks and climate change doesn't get prevented anyway.