Since the summer of last year, the US dollar has appreciated nearly 20%, and the strong dollar has knocked down US exports and reduced US corporate profits, weakening one of the world's largest economies and two engines of economic growth.

In another growth engine, the emerging market, the sharp decline in commodity prices caused by the appreciation of the dollar has caused some economies to stagnate or shrink, and to increase the US dollar debt burden.

Even the Fed worried that the exchange rate effect was a factor in the decision to postpone interest rates last month.

The exchange rate may still play a key role in the Federal Reserve's decision this week.

But with the restatement of the currency war, it is hard to imagine that the dollar will weaken.

As the European and Japanese authorities are concerned about the impact of the appreciation of the euro and yen on their respective economies, they will try to avoid stronger currencies.

The general view of analysts in the foreign exchange market is that the US dollar will appreciate against the main currencies in the coming year.

Citigroup chief economist Butil said.

Weakness may help prevent the whole world from slipping into a new recession or falling into a situation where real growth is far below potential level.

He was a member of the Bank of England's Monetary Policy Committee (MPC).

"The global economy will benefit from faster growth in the US," he said.

"If this is achieved through joint stimulus of monetary and fiscal policy and implemented in an appropriate way, it will help the world economy obtain an important source of demand."

This puts an end to the possibility of depreciation of the US dollar for some worrying reasons, such as investor's lack of confidence in the United States and so on.

The US economy accounts for about 1/4 of global output. According to IMF, the contribution of emerging markets to global economic growth will exceed 70% in the 10 years to 2020, and the weakening of US dollar may have a strong stimulative effect.

The study of Deutsche Bank economists shows that this year's net export drag on US economic growth is about 0.7 percentage points, larger than the 0.5 percentage points they predicted in January.

Deutsche believes that the impact of the appreciation of the dollar will account for 0.5 percentage points, which will last until the beginning of next year.

JP Morgan analyst to past

The study of debt surging has found that the economic growth of these countries is always hit by the bursting of the debt bubble (basically US dollar borrowing).

Their conclusion is that in the next three years, the average growth rate of GDP in emerging markets will probably slow down from 5.5% in the past five years to 2.6%.

In the absence of a joint statement and joint intervention by the group of seven G7, it is not clear how to make the dollar depreciate because basically all the parties involved want the currency to depreciate.

The Fed could argue that it would not raise interest rates for a long period of time, basically the return of "forward-looking guidance", which would make the dollar inferior.

But in the United States so close to raising interest rates, the Fed's policy makers are unlikely to do so.

David Bloom, head of HSBC's foreign exchange strategy, believes that people are too focused on the US dollar and that governments, central banks, businesses and consumers can decide the trend of global growth.

"The bottom line is:

It can't save the whole world, "Bloom said. It is also optimistic that the euro will rise to 1.20 dollars next year.

From the international business machines (IBM) IBM.N to WAL-MART (WMT.N), the earnings season shows that the strong US dollar has depressed the profitability of US companies.

The profits of the S & P 500 constituent companies will drop by nearly 4% during the quarter.

Emerging market banks and businesses that borrow huge amounts of US dollar funds are also vulnerable to a stronger US dollar.

According to Charlie Robertson of Renaissance Capital, the scale of international bond issuance in emerging markets has increased two times over the past 10 years to 2 trillion (trillion) dollars.

Most of them are denominated in US dollars.

"The depreciation of the US dollar is quite beneficial to emerging markets, because its external debt burden will be better controlled and commodity price trends will be better," he said.

Emerging markets have long ago slowed down.

In January, the world bank estimated that the developing economies will expand by 4.8% this year, but it will be revised down to 4.4% in June.