The loss to them if they ignited the atmosphere would be another 30 or so years of life. The loss to them if they lost the war and/or were killed by their enemies would also be another 30 or so years of life.
This assumes they don’t care about their children and grandchildren after their death.
This assumes they don’t care about their children and grandchildren after their death.
...and the children and grandchildren of their enemies, and the millions of currently-living people not involved in the war, and etc.