LONDON — In 2008, at a time of financial peril, the world united to restructure the global banking system. In 2009, as trade collapsed and unemployment rose dramatically, the world came together for the first time in the Group of 20 to prevent a great recession from spiraling into a great depression.

Now, facing a low-growth austerity decade with no national exits from long-term unemployment and diminished living standards, the world needs to come together in 2011 to agree on a financial and economic strategy for prosperity far bolder than the 1940s' Marshall Plan.

Time is running out on the West, because Europe and America have yet to digest the fact that all the individual crises of the last few years — from the subprime crisis and the collapse of Lehman Brothers to Greek austerity and Ireland's near-bankruptcy — are symptoms of a deeper problem: a world undergoing a far-reaching restructuring of economic power.