In charts we live... and in charts we delight.
Here is a neat summary of global current account balances (horizontal axis) against the rate of change in the current account over 12 months through 2Q 2015.
Source: @NickatFP
6th largest surplus: Russia. Fastest growth in surplus: Russia. So that petrodollar economy, then... like, say Saudi Arabia?..
Now, think of the favourite theory of 'sustainability' advanced by the likes of the Euro-centric Bruegel and its followers. The said theory rests on sustainability being equivalent to medium-term or long-term external balances... either that theory (underpinning most of the official EU economic mantra) off the rocker or... take a look at the chart again.
No comment beyond.