The good news that Europe's economy grew at the modest rate of 0.3 percent in the final quarter of last year was reinforced by the U.S. Congress vote to avoid a default and raise the debt limit.

Despite the temporary disruptions of an unusually harsh winter, the world's two biggest economic blocks are helping rather than hindering the global economy.

That is a mercy since its other components aren't in good shape.

On Japan, the jury is out on the daring gamble of Prime Minister Shinzo Abe to print money and stimulate inflation to get Japan's economy moving again despite the horrendous levels of debt.

Japan's stock market has stumbled but exports have risen, advance orders and machinery orders are still rising and Japanese corporations are forecasting a rise in earnings much higher than those in Europe and the United States.

Japan's economy is still as big as those of France and Germany combined so a Japanese return to growth is unexpected good news. It is also worth noting that for the past seven years, measured by gross domestic product per person of working age, Japan has outperformed the United States, which is some compensation for its fast-aging population.

The big concern is that most other Asian countries, and particularly China, are slowing. Clearly Asia will to grow dramatically over the long term but the process now seems likely to be bumpy and uneven, marked by boom-bust cycles like 1998 and the bust that may be resuming currently, and by other less predictable setbacks as countries seek to avoid the middle-income trap.

India's growth is already down to just more than 4 percent, inflation at 11 percent and it faces a tricky election this year, with the populist new Common Man Party likely to deny the business-friendly and reform-minded Narendra Modi and his Bharatiya Janata Party a clear mandate.

China faces a series of fundamental challenges in demographics, pollution, water and energy supply. It must also control its overheated credit market and manage the great shift from an investment-led to a consumption-led economy. Each of these will tend to reduce current growth rates, even while Beijing navigates the socio-political tensions that come from a rising middle class that seems to want reforms of corruption and media/Internet controls.

With one-fifth of the world's population, China has only 7 percent of global water resources and those are unevenly divided between north and south. Each Chinese citizen has only one-quarter of the world's average share of fresh water per capita.

Afflicted by recurrent droughts, with the Yellow River repeatedly drying up, the Beijing water table has fallen drastically in recent years as artesian wells run dry.

The World Bank has forecast that by 2020 there will be 30 million water stress refugees in China. More than half of China's 660 cities suffer from water shortages, affecting 160 million people. The groundwater of 90 percent of cities and 75 percent of rivers are dangerously polluted. As a result, 700 million people drink contaminated water every day.

It will be very difficult for the Beijing leadership to manage all of these challenges successfully. At the same time growth has fallen from 11 percent at the height of the boom to the 7 percent range last year and 5 percent looks likely by 2016 and President Xi Jinping tries to shift the economy from investment-led to a great reliance on consumption. But even at that slower rate of growth, China's consumer spending by 2025 should be on a par with that of Europe.

The economies of the other two BRIC countries -- Brazil and Russia -- are stalled. Of the once-dynamic emergent markets, Turkey, Indonesia, Nigeria, Argentina and South Africa are all in difficulties.

As the International Monetary Fund predicted last year, with the winding-down of the U.S. Federal Reserve's quantitative easing Fed's program promising higher U.S. interest rates, money is returning to the United States and leaving emergent markets with a cash flow problem.

The IMF warned last October: "The prospect of reduced monetary accommodation in the U.S. may cause additional market adjustments and expose areas of financial excess and systemic vulnerability. In this setting, emerging market economies may face exchange rate and financial market overshooting as they also cope with weaker economic outlooks and rising domestic vulnerabilities; some could even face severe balance of payments disruptions."

So it has proved. So much now depends on the United States and Europe recovering fully.

The United States looks to be in good shape but outside of Britain and Germany the same can hardly be said of Europe.

France is still bumping along the bottom, despite President Francois Hollande's latest promises of structural reform. And Italy has just been plunged into a new political crisis with the resignation of Prime Minister Enrico Letta. A new euro crisis now is the last thing the world needs.