One of the most compelling virtues of the recent 2219: Futures Imagined exhibit at the ArtScience Museum was that it made a radical scenario - Singapore as a high-rise Venice, with canals, hanging gardens and vertical farming - appear entirely plausible. But 2219 could well be 2119, or even sooner.

I have frequently noticed this paradox in scenario-planning exercises. A decade ago, while advising the US National Intelligence Council's Global Trends 2030 programme, the team posited a future in which urbanisation, technology and capital accumulation had brought about a landscape in which cities, federal governments, provincial authorities and corporate supply chains compete for influence across various enclaves and legal zones. My response: This is the world of 2013, not 2030.