The world system is at an uncertain branch point from which a wide range of possible, qualitatively different, futures could unfold before the end of the Century. Two decades ago, the Global Scenario Group (GSG) published three archetypical sets of scenarios of the future of the planet. These are revisited in the light of the changes and developments that happened since then, plus the emerging new trends, looking for meaningful early warning signals and potential strategic causal nodes that could help steering towards a sustainable global future.