CAMBRIDGE – With economic growth slowing significantly in many major middle-income countries and asset prices falling sharply across the board, is the inevitable "echo crisis” in emerging markets already upon us? After years of solid – and sometimes strong – output gains since the 2008 financial crisis, the combined effect of decelerating long-term growth in China and a potential end to ultra-easy monetary policies in advanced countries is exposing significant fragilities.The fact that relatively moderate shocks have caused such profound trauma in emerging markets makes one wonder what problems a more dramatic shift would trigger. Do emerging countries have the capacity to react, and what kind of policies would a new round of lending by the International Monetary Fund bring? Has the eurozone crisis finally taught the IMF that public and private debt overhangs are significant impediments to growth, and that it should place much greater emphasis on debt write-downs and restructuring than it has in the past?The market has been particularly brutal to countries that need to finance significant ongoing current-account deficits, such as Brazil, India, South Africa, and Indonesia. Fortunately, a combination of flexible exchange rates, strong international reserves, better monetary regimes, and a shift away from foreign-currency debt provides some measure of protection.Nonetheless, years of political paralysis and postponed structural reforms have created vulnerabilities. Of course, countries like Argentina and Venezuela were extreme in their dependence on favorable commodity prices and easy international financial conditions to generate growth. But the good times obscured weaknesses in many other countries as well.The growth slowdown is a much greater concern than the recent asset-price volatility, even if the latter grabs more headlines. Equity and bond markets in the developing world remain relatively illiquid, even after the long boom. Thus, even modest portfolio shifts can still lead to big price swings, perhaps even more so when traders are off on their August vacations.Until recently, international investors believed that expanding their portfolios in emerging markets was a no-brainer. The developing world was growing nicely, while the advanced countries were virtually stagnant. Businesses began to see a growing middle class that could potentially underpin not only economic growth but also political stability. Even countries ranked toward the bottom of global corruption indices – for example, Russia and Nigeria – boasted soaring middle-class populations and rising consumer demand.This basic storyline has not changed. But a narrowing of growth differentials has made emerging markets a bit less of a no-brainer for investors, and this is naturally producing sizable effects on these countries’ asset prices.A step toward normalization of interest-rate spreads – which quantitative easing has made exaggeratedly low – should not be cause for panic. The fallback in bond prices does not yet portend a repeat of the Latin American debt crisis of the 1980’s or the Asian financial crisis of the late 1990’s.Indeed, some emerging markets – for example, Colombia – had been issuing public debt at record-low interest-rate spreads over US treasuries. Their finance ministers, while euphoric at their countries’ record-low borrowing costs, must have understood that it might not last.Yes, there is ample reason for concern. For one thing, it is folly to think that more local-currency debt eliminates the possibility of a financial crisis. The fact that countries can resort to double-digit inflation rates and print their way out of a debt crisis is hardly reassuring. Decades of financial-market deepening would be undone, banks would fail, the poor would suffer disproportionately, and growth would falter.Alternatively, countries could impose stricter capital controls and financial-market regulations to lock in savers, as the advanced countries did after World War II. But financial repression is hardly painless and almost certainly reduces the allocative efficiency of credit markets, thereby impacting long-term growth.The emerging-market slowdown ought to be a warning shot that something much worse could happen. One can only hope that if that day should ever arrive, the world will be better prepared than it is right now.Kenneth Rogoff, Professor of Economics and Public Policy at Harvard UniversityCopyright: Project Syndicate