Originally Posted by dragonrider
Good idea for a story. Are you thinking about a short story or a novel-length book?
If the life expectancy were to rise suddenly, it would not take long at all for some very serious population problems to begin happening. The planet is already very overpopulated. We are already running low on fresh water, and water will be a big problem before food is. The oceans are overfished, so any more stress on those ocean ecosystems, and the major fisheries will completely collapse as they have already done in some areas.
Some other ideas: We already have some social problems because of longer life expectancies. In the US, when the Social Security system was estabilshed, most people didn't live to 65, and those who did, didn't live much longer than that. So setting 65 as the age when you could start collecting benefits did not put much of a burden on those working to support the system. And it just meant that the very oldest people did not have to work into their very last days. Now the life expectancy is over 80, and it goes up something like 3 months every year. People go on Social Security and live on it for years. It is beginining to cost huge amounts of money to support people on this porgam for so many years. If life expectancy suddenly jumped to 100, there would be some major disruption to programs of this sort.