CERNOBBIO, Italy (AP) — Experts and leaders gathered in Italy may disagree on the cure, but the malady seems clear: the world economy faces a "perfect storm" of risks that include prolonged crisis in a structurally flawed Europe, political paralysis pushing America off a "fiscal cliff," a slowdown in the emerging economies drying up the last of global growth, and the spectacularly destabilising prospect of war over Iran's nuclear programme.

A world of such unpredictable peril is also one in which jitters suppress the appetite for private and corporate risk, yielding meagre investment and low consumption and prolonging the woes that snuck up on a booming world in the summer of 2007 as a "credit crunch", mushrooming a year later into the Great Recession.

Many attendees at the annual Ambrosetti Forum at Lake Como on Friday fretted about mounting US debt and the Europe's inability to balance electorates' apparent insistence on national sovereignty with the need for regional coherence to salvage the teetering euro.

But economist Nouriel Roubini predicted years of gloom almost regardless of what is decided.

That analysis is rooted in the specific nature of this crisis, a downward spiral in which a financial meltdown largely caused by excess credit was defused by a blast of public spending; that 2009 stimulus, widely credited with avoiding a global depression, pushed some governments too far into the red for the markets' liking — a "sovereign debt crisis"; and this is turn was attacked through severe austerity measures that suppressed spending to the point that countries cannot grow their way back to prosperity.

"History suggests that whenever (there is) a crisis with too much private debt first and public debt second you have a painful process of deleveraging," said the famously apocalyptic New York University professor, a glowering fixture at such international talk-shops.

"That would imply many years, up to a decade, of low economic growth. And guess what? Economic recovery in the US has been unending and in the eurozone and UK there's outright economic contraction right now, and that's not going to change unfortunately in the next few years."

The grim prognosis was consistent with new figures released a day earlier by the OECD, a club of the world's richest nations. Its report found that the global economy is slowing and that the G7 economies would grow at an annualised rate of just 0.3 per cent in the third quarter of 2012. Furthermore, the OECD found, the continuing eurozone crisis "is dampening global confidence, weakening trade and employment and slowing economic growth" worldwide.

Ali Babican, Turkey's deputy prime minister for economic and financial affairs, bemoaned the lack of a sense of common European interest — alluding to the lack of sympathy in places like Germany for the woes of an economically hammered eurozone colleague like Greece.

Increasingly popular is the argument that it is fundamentally illogical to allow a country to blunder into massive debt if it doesn't have the monetary tools to diminish its debt — lacking a currency to devalue.

Roubini said that the only solution was to extend the euro's monetary union in the direction of a banking, fiscal or even political union, at least to the point of having a single eurozone finance minister empowered to veto individual countries' budgets for exceeding a given deficit limit. "Today the eurozone is disintegrating ... either move forward or you're going to fall off a cliff."