Well excuse me anonymous BarCap analysts, but you are pretending to be more stupid than you actually are. The carry trade everybody's talking about is more about capital gains than about pure yield carry, and your measures are not adapted to this. These measures were useful when the carry trade was about shorting yen and going long higher yielding currencies (notably as you mention, AUD) using enormous leverage, hence the need to monitor volatility. The topic du jour is about borrowing dollars and going long low- or zero-yielding things like commodities, stocks or other low-yielding bonds and currencies, presumably with a much lower leverage. Volatility has become less important, but more to the point, AUD volatility is pretty much irrelevent to the debate.
The size of carry traders is notoriously difficult to measure, and there is considerable speculation on their size based on very incomplete evidence. Consider, however, a measure of the classic incentive to put on carry trades — volatility-adjusted spreads. We use two such measures, the volatility-adjusted spread between AUD and JPY and the volatility-adjusted spread between AUD and USD. In each case, we divide the 10y yield differential between by one year implied volatility.
These measures do not encourage the view that carry trades would be put on in size . Whatever the incentives from the rate differentials, implied volatilities remain high enough to discourage carry trades. In both cases, the incentives are not only well below the peak, they are well below the average.
If anything, this suggests that the market may be overestimating the extent of carry trades now in place and underestimating the potential for carry trades to be instituted if implied volatilities pull closer toward historical norms and realized volatility.
A more interesting argument comes from David Rosenberg (I actually think he borrowed it, I saw that somewhere else recently):
Historically, there is no correlation at all between the DXY index (the U.S. dollar index) and the S&P 500. In the past eight months, that correlation is 90%. Ditto for credit spreads — zero correlation from 1995 to 2008, but now it has surged to 90% since April. There was historically a 70% inverse correlation between the U.S. dollar and emerging markets, such as the Brazilian Bovespa, and that correlation has also increased to 90% since the spring. Even the VIX index, which historically has had no better than a 20% correlation with the U.S. dollar, has now sent that correlation surge to 90%. Amazing. The inverse correlations between the U.S. dollar and gold and the U.S. dollar and commodities were always strong, but these too have strengthened and now stand at over 90%.