OIL PRICES have risen by about 30% since January and remain well above the range of $22-$28 a barrel recommended by the Opec oil cartel.

Last week Brent crude hit a record $41.50 a barrel before easing back to $41.05. American light crude futures jumped to $44.77 — a 21-year high.

Here we answer your questions about the surge in prices.

Why have oil prices gone up?

Global economic expansion is behind much of the rise. Industrialised countries such as America, Britain and Japan have been enjoying a simultaneous recovery in growth.

Emerging markets such as China and India are also experiencing strong growth. Demand for oil has risen by 20% in China over the past year.

At the same time, oil supplies are low and at risk from terrorism in the Middle East.

Will prices go higher?

Barclays Capital, the investment bank, has increased its forecasts for Brent Crude to $41.10 for the fourth quarter. Kevin Norrish, the bank’s commodities analyst, thinks prices could go as high as $50 a barrel.

He said: “The risk to oil supplies among many producing nations remains high. The political situation in Iraq is not improving and there are potential supply problems in Russia, Nigeria and Indonesia.

“There is a lack of oil- refining capacity, and production by both Britain and the US is falling fast. Saudi Arabia has some spare capacity but not that much. This all points to higher oil prices for longer.”

What effect do high oil prices have on the economy?