CAMBRIDGE – After nine dreary years of downgrading their GDP forecasts, macroeconomic policymakers around the world are shaking their heads in disbelief: Despite a populist-propelled wave of political tumult, global growth is actually set to outperform expectations in 2017.

It’s not just American exceptionalism. Although US growth is very strong, Europe has been outperforming expectations by more. There is even happy news for emerging markets, which are still bracing for US Federal Reserve interest-rate hikes but have gained a better backdrop against which to adjust.

The broad story behind the global reflation is easy enough to understand. Deep, systemic financial crises lead to deep, prolonged recessions. As Carmen Reinhart and I predicted a decade ago (and as numerous other scholars have since corroborated using our data), periods of 6-8 years of very slow growth are not at all unusual in such circumstances. True, many problems remain, including weak banks in Europe, over-leveraged local governments in China, and needlessly complicated financial regulation in the United States. Nonetheless, the seeds of a sustained period of more solid growth have been planted.

But will the populist tide surging across the advanced economies drown the accelerating recovery? Or will the recovery stifle leaders who confidently espouse seductively simple solutions to genuinely complex problems?

With the International Monetary Fund/World Bank meetings coming up later this month in Washington, DC, leading central bankers and finance ministers will have ringside seats at Ground Zero. Who can doubt that US President Donald Trump will make a Twitter punching bag out of any of them who dares criticize his administration’s planned retreat from open trade and leadership in multilateral financial institutions?

Before then, Trump will host Chinese President Xi Jinping at Mar-a-Lago, his "winter White House.” It is hard to overstate how much rides on the Sino-US relationship, and how damaging it would be if the two sides could not find a way to work together constructively. The Trump administration believes that it has the bargaining tools to recalibrate the relationship to America’s advantage, including a tariff on Chinese imports or even selectively defaulting on the more than $1 trillion the US owes to China. But a tariff would eventually be overturned by the World Trade Organization, and a default on US debt would be even more reckless.

If Trump can persuade China to open up its economy more to US exports, and to help rein in North Korea, he will have achieved something. But if his plan is for the US to retreat unilaterally from global trade, the outcome is likely to hurt many US workers for the benefit of a few.

The threat to globalism seems to have waned in Europe, with populist candidates having lost elections in Austria, the Netherlands, and now Germany. But a populist turn in upcoming elections in either France or Italy could still tear apart the European Union, causing massive collateral damage to the rest of the world.

French Presidential candidate Marine Le Pen wants to kill off the EU because, she says, "the people of Europe do not want it anymore.” And while opinion polls have the pro-EU Emmanuel Macron beating Le Pen decisively in the election’s second-round runoff on May 7, it is hard to be confident in the outcome of a two-person race, especially given Russian President Vladimir Putin’s support for Le Pen. Given the unpredictability of an angry electorate, and Russia’s proven capacity to manipulate news and social media, it would be folly to think that Macron is a lock.

Italy’s election is not for another year, but the situation is even worse. There, populist candidate Beppe Grillo is leading polls and is expected to pull in about a third of the popular vote. Like Le Pen, Grillo wants to pull the plug on the euro. And, while it is hard to imagine a more chaotic event for the global economy, it is also hard to know the way forward for Italy, where per capita income has actually fallen slightly during the euro era. With flat population growth and swelling debt (over 140% of GDP), Italy’s economic prospects appear bleak. Though most economists still think exiting the euro would be profoundly self-destructive, a growing number have come to believe that the euro will never work for Italy, and that the sooner it leaves the better.

Kenneth Rogoff, Professor of Economics and Public Policy at Harvard University

Copyright: Project syndicate