Each of the last five major downturns in global economic activity has been immediately preceded by a major spike in oil prices. Sometimes (e.g. in the 1970s and in 1990), the surge in oil prices has been due to supply restrictions, triggered by Opec or by war in the Middle East. Other times (e.g. in 2008), it has been due to rapid growth in the demand for oil.

But in both cases the contractionary effects of higher energy prices have eventually proven too much for the world economy to shrug off. With the global average price of oil having moved above $100 per barrel in recent days – about 33 per cent higher than the price last summer – it is natural to fear that this latest oil shock may be enough to kill the global economic recovery. But oil prices would have to rise much further, and persist for much longer, for these fears to be justified.

With global oil supply already impacted by Libyan shut-downs, the threat of an oil shock has moved well beyond the realms of the theoretical. According to recent reports, about half of Libya’s 1.6m barrels per day of oil output have been knocked out, and this has been enough to trigger a rise of about $14 per barrel in the spot price of oil in the past week.

Total Libyan oil production is less than 2 per cent of the world total, and it is of course most unlikely to be lost on a permanent basis. According to