We’re now beginning to see government agencies put figures on the oil supply deficit in coming years.

The US Department of Energy information agency say that current data points to a supply deficit of 5 million barrels a day by 2015, rising to 20 million barrels a day in 2020. This estimate, calculated in April 2009 after the economic crash in western countries, is based on slowly rising global demand, largely on foot of increased consumption in China and India.

But rather than translating into queues at petrol pumps, the deficit is expected to prompt price increases over time as demand runs ahead of supply.

Fatih Birol of the International Energy Agency advises that “we have to leave oil before oil leaves us”. Signs of that remain thin on the ground, the car park of Leinster House being a case in point.

And the ill-fated attempt to drill for oil one mile below the ocean surface off the coast of Louisiana is testament to the complexity, even desperation, brought on by peak oil. It’s not easy to manage oil exploration 1,500 metres underwater where divers can only operate locked inside submarines.

What’s more, gaining a picture of just how much oil is escaping every day in the gulf is very difficult. In a ‘worse-case’ scenario, the spill could rise to 100,000 barrels a day, according to BP. The current estimate is 60,000 barrels a day, according to the US government. Let’s take the lower figure.

Some 60,000 barrels converts to 9.6 million litres. What would that be in terms of Irish dairy production, for example? To produce 9.6m litres of milk a day would take a staggering 420,000 cows. Or put it another way, the standard home delivery oil truck carries 20,000. Now picture 480 of these trucks circled on the beaches of a small island spilling their contents into the sea every day.