Driving forces cited in the study include increasing life expectancy, elimination of pensions,
economic uncertainy and re-visioning of later life towards purpose and social engagement.
Variability (
uncertainy) is the big challenge for these kinds of approaches.»
Note that part of
the uncertainy in all this is the time uncertainty — from the ice core records, we can pick a rather precise time and look at a rather precise number for greenhouse gas concentrations, but pinning down the magnitude albedo change at exactly the same time (since albedo is not globally uniform, obviously) is impossible.