Systems of ethics that address intergenerational issues should provide guidance on how to balance the interests of those people nearing the end of their lives, those just beginning, and those in between, and also on how to balance the interests of those people alive now and those who will be in the future (if those who are alive now don't mess things up too badly).
What are the current schools of thought on these issues? (Or, if giving a summary is difficult, where is a good place to learn about current thought on these issues?)
(Note that while this has always been an important part of ethics, it is particularly critical now that we are able to affect our environment in such dramatic ways; in previous centuries, the answer "act morally now, and the future will sort itself out" would sound plausible. This century, however, that sounds far too naive.)