Hmm. Go read this (go quick, it'll be behind a paywall in the next 24 hours).
The sort of idle prognostications that I enjoy. Only one analyst talked about the energy crisis, and there clearly without a full appreciation of the implications. None of them talked about global warming.
I think by 2031 we will be in a radically different world. We'll either have sorted out the energy issues, powered down, and be on a sustainable path - or we won't, in which case we can expect increasing disorder, and probably an Islamic worldwide caliphate.
More likely, I think there will be several interlinked crises; nuclear war in the middle east (probably the end of Israel); a return to a multipolar world; hugely increased localism and regionalism; a drop of population (10% maybe); a lot of nervousness; a lot of human migration. Yet for the survivors, something positive to hope for.