ECONOMISTS are constantly urging governments to adopt policies that would reduce global imbalances—which, in crude terms, means that China should slash its current-account surplus and America its deficit. Yet they ignore the biggest imbalance of all: the current-account surplus that planet Earth appears to run with extraterrestrials. In theory, countries’ current-account balances should all sum to zero because one country’s export is another’s import. However, if you add up all countries’ reported current-account transactions (exports minus imports of goods and services, net investment income, workers’ remittances and other transfers), the world exported $331 billion more than it imported in 2010, according to the IMF’s World Economic Outlook. The fund forecasts that the global current-account surplus will rise to almost $700 billion by 2014.Are aliens buying Louis Vuitton handbags? Are little green men bagging the best sunbeds by the hotel pool? The more down-to-earth explanation is that the global surplus reflects statistical errors. Either the current-account deficits of countries such as America are being understated or the surpluses of countries like China are being overstated, and by a rising amount.