- The dollar's dominance is being threatening by growing debt in the US, economist Barry Eichengreen said.
- High debt caused the downfall of the British sterling as a global currency in the early 1900s, scholars say.
- The US deficit could notch 181% of GDP over the next 30 years, according to a CBO estimate.
The dominance of the dollar depends on whether or not the US can get its debt problems under control, according to former International Monetary Fund official Barry Eichengreen.