What If the Allies Tried to Disrupt the Holocaust - through bombing the railways to the death camps, or through Covert Sabotage Tactics?
What if the huge financial backing that has gone to nuclear power since World War Two had gone mostly to renewables instead?
What If The Koch Brothers Were Pro-Eco?
What if Stanislav Petrov had launched a USSR nuclear retaliation to the received reports of incoming US missiles, at the height of 1980s Cold War mutual mistrust?