When world leaders arrive in London for an economic crunch summit on Thursday, they will find themselves inundated by hectic media coverage and the global hopes for a panacea for the economic woes.

But those hopes will be chilled if the Group of 20 economies fail to have a clear picture of their policy and system pitfalls before they hustle to find solutions.

Despite the fact that the financial crisis originated from the burst of the US housing bubble, authorities and economists have differed on the causes of the crisis. One of the most compelling arguments is that high savings by Asian countries like China helped fuel the US property boom.

The view was supported by prominent US figures, such as Federal Reserve Chairman Ben Bernanke. The Fed chief said in mid-March that, while the United States failed to effectively use massive capital inflows, its trading partners were also to blame for the global imbalances that were the fundamental causes of the financial crisis.

While Bernanke was brave enough to acknowledge the US and other industrial countries lacked risk management and oversight of the financial sectors, he should have equal courage in revealing the root causes of the crisis -- including drawbacks in the U.S. policy and the current US-dominated international financial system, instead of making wrong links between Asia's high savings and the US overspending.

As China's central bank governor Zhou Xiaochuan cited figures as saying last week: "this round of low savings and high consumption in the United States commenced in mid-1990s, while the savings ratio of east Asian countries only surged after the 1997-1998 Asian financial crisis and China's savings ratios did not begin to increase until 2002. The difference in time distribution indicates there is no significant causal relationship between the two."

The Fed pursued a low-interest rate policy to save the US economy from a contraction in the 1990s, which encouraged excessive spending and was widely accepted as the root cause of the sub-prime crisis.

As Bernanke tried to get other countries to share the duty, he seemed to have neglected another thing: Since the US dollar is the dominant international reserve currency, capital inflows to the United States is inevitable when other countries turned excessive savings into foreign reserves.

In fact, Washington is more than happy to maintain the dominance of the greenback. After China's Zhou called for the establishment of a new international reserve currency that is disconnected from any individual countries last week, the US President Obama and Treasury Secretary Timothy Geithner quickly defended the dollar's position as the top reserve currency.

Although even Zhou acknowledged it will take a very long period to set up a new global reserve currency, the United States and the international community should at least conduct serious introspection on the current system's flaws.