Watching the developments in the currency markets feels very similar to reading Agatha Christie’s “Murder on the Orient Express”. <br /><br />Penned in the 1930s in Istanbul, Christie’s thriller has you on the edge of your seat with every twist and turn of the plot. <br /><br />It was therefore appropriate that last week’s meeting of the World Bank and IMF was located on the banks of the Bosporus. Where better to discuss the issue of the demise of the world’s reserve currency than at the point where east meets west? <br /><br />But to determine the future health of the dollar, those attending, like detectives, had to read between the lines and pick up on the clues. <br /><br />That’s because none of the policy makers present were willing to openly say that the future of the greenback is in question. Christine Lagarde, France’s Finance Minister, told me that she firmly believes in a “strong dollar”. Yet she quickly went on to say that Europe should not shoulder the burden associated with rebalancing the global economy. The implication being that as the world seeks a new equilibrium it will be inevitable that we will see big shifts in the value of various currencies. <br /><br />And it was a similar theme when it came to the views of the Governor of Saudi Arabia’s central bank. Speaking to CNBC, he strongly denied that there was any move to price oil in anything other than dollars. Yet when asked if it would be a good idea, he replied “not now”. The response, once again, implying that things could be very different in the future for the US currency.<br /><br />Now none of our economic leaders anticipate that the status quo is going to change any time soon. But the once absolute certainty that the greenback will remain the world’s reserve currency is starting to fray. <br /><br />The dollar’s ultimate decline is, however, only a symptom of a wider move that is happening in the world economy. The planet’s economic growth engine is now no longer to be found in America – it is instead located in the emerging markets of Asia. <br /><br />This is the world’s new Orient Express and if Christie had been writing her books now she may well have sent Poirot east rather than west. <br /><br />Whether he would have been able to discover the ultimate cause of the dollar’s demise is another question. Guy Johnson co-anchors European Closing Bell and Europe Tonight weekdays on CNBC.