There is no way to put a yen value on the loss of human life from last week’s earthquake and tsunami. Estimates of economic cost are possible, but should be treated with great caution.

The expense of rebuilding can be estimated. Barclays Capital gives a range of Y5,000bn-Y10,000bn ($60bn-$120bn). Barring further nuclear-related damage, the final count could well come at the lower end. The cost of reconstruction after the 1995 Kobe earthquake was Y10,000bn, but as of Thursday National Police Agency counts suggest far less damage this time: 12 per cent as many damaged or collapsed buildings.

The upper end of the BarCap range is the equivalent of 2 per cent of Japan’s annual gross domestic product. The two numbers, however, are not directly comparable. The reconstruction will take years and every expense is not a loss; the new structures should be safer and higher quality than the old. In any case, the right comparison is not with GDP – a crude measure of output – but with what the physical stock would have looked like a few years hence without this natural disaster. That, though, is hypothetical (just what would have been constructed?) and misleading (natural disasters are frequent in Japan).