The world may be basking in the warm glow of economic recovery, but some observers are warning of an unseen spectre, lurking in the background.

Just as the global economy has strengthened in recent months, so has the price of oil.

The warning bells are sounding.

It's easy to forget the first global crisis of 2008, which took place just months before the October stock market crash.

In July 2008, it was oil prices - and subsequently the cost of petrol at the pump - which was front-page news.

At its worst, it reached about $US147 a barrel.

In some countries, governments wore the blame and in turn pointed the finger at producers and refiners.

In others (like India), government subsidies were increased at great cost to the budget bottom line.

Isolated island communities feared they'd not be able to afford to run their generators, and the worldwide poor suffered shocking food price inflation.

So in one sense, we were saved by the effects by the global financial crisis, which pushed oil demand lower and resulted in a drastic easing of prices.

Within months it plummeted to just over $US30 a barrel.

Problem, apparently, solved.

But in recent months the oil price has been slowly trending upwards again, and is now hovering at around $US85 a barrel.

A couple of weeks ago, oil futures got closer to $US90.

According to a member of the Infrastructure Australia Council, Curtin University's Professor Peter Newman, a further oil price rise is inevitable as increasing demand impacts upon dwindling supply.

"It dropped down very quickly after the global financial crash led to very little demand but its gone back to [more than $US80] because there just isn't the supply around," he said in an interview from Perth.

"The fact that now only 14 countries are exporting oil - Australia is depleting very rapidly at about 11 per cent a year - we are going down and so the major oil sources are running out apart from a few in the Middle East, we've got this major crunch that has been predicted for a long time beginning to unfold.

"We are seeing the reality of peak oil and the impact on the economy."

So-called peak oil theory emerged in the 1990s when a group of scientists predicted a massive price rise in the first decade of this century, simply because too many consumers would compete to buy a dwindling energy resource.

Professor Newman says that peak oil was reached in 2008, and that prices have been artificially suppressed since then.

He says the 2008 crunch contributed to the global financial crisis.

"Peak oil did happen, I believe, in 2008," he said, "140 dollars a barrel was a massive increase and it didn't happen because some oil exporting country had a revolution or something - it just happened because we couldn't produce enough to meet demand, and that's what peak oil is about.

"Subprime mortgages were largely out on the urban fringes miles away from work, and people had to drive and when the price of fuel tripled in American cities they couldn't pay their mortgages so that's what caused the damage to the economy and it just rippled around the world," he said.

"As the demand increases again the supply crunch will happen and the price will go up.

"The recovery would very quickly unravel, we'd go into the "W"[shaped recovery] rather than the "V" and that "W" would have a very shaky last part of the letter as well and coming out of it would be not as easy to predict as all of the old formulae would be unravelling."

Professor Kjell Aleklett is president of the Association for the Study of Peak Oil and Gas, which is also known as ASPO.

In an interview from Sweden, he said he agreed the world has reached its peak in oil production.

"The fact is we are producing less oil now than we did in 2008, so just now we have 2008 as the peak year for peak oil." Professor Aleklett said.

"Because oil is so related to the global economy and the global economy is just weak now and that is why the price of oil is not jumping high."

But Professor Aleklett isn't entirely pessimistic.

He says he has confidence that the market, and in the world's governments, will ensure that an oil-price-driven catastrophe will be avoided.

"I'm one of those people that believe that it's not very possible to have a high price of oil because that would mean the end of globalisation" he said.

"The fact is that [if the price hit] $200 a barrel then there an airline industry [would not exist] any longer."

The University of South Australia's Dr Vlado Vivoda also says a crunch can be avoided.

"What peak oil theorists miss out on is the fact that with improvements in our technologies and improvements in a drop in oil production costs what it is considered oil is changing," he said.

"I see the definition changing of what is exploitable oil [and] changes in levels in technological efficiency and with the changes in the exploration or the production of oil."

Dr Vivoda says that innovations like hybrid cars will also help suppress demand.

"[They are] right to point out that demand growth will return with the start of the economic recovery and I do not deny that," he said.

"What I see however happening is that the demand growth will actually flatten a bit."

"Before the recession we had demand growth of something like 1.5 to 2 per cent a year, and what I believe will happen following the recovery is demand growth in the area of 1 and 1.5 per cent a year, primarily because following each and every oil price spike - and this is in the last 60 years - the oil demand growth has slowed down following the recovery."

Whatever the truth, some governments - big and small - have started to prepare for the possibility of an oil crunch.

In the interests of energy security, US president Barack Obama recently opened up a large stretch of his country's coastline to oil drilling, angering his environmental support-base in the process.

In announcing his decision, president Obama justified his decision in the interests of his country's long-term security.

"We need to move beyond the debates of the left and the right, between business leaders and environmentalists, between those who claim drilling was a cure-all and those who claim it has no place," he said.

You can read more about that decision here.

Several municipal councils in Australia have also drawn up oil security strategies.

The mayor of Maribyrnong City Council in metropolitan Melbourne, Councillor Sel Sanli, says his local government is now prepared for an oil crunch thanks to a "Peak Oil Policy and Action Plan".

"This policy showed how dependent we are on oil," Mr Sanli said.

"It is pretty much scary to learn how much we are dependent on oil to provide your normal services ... just like we are dependent on water.

"Every day businesses, organisations go through and assess their risks out there and peak oil is one of these risks ... so if peak oil happens and that oil supply is cut out how can the organisation continue to deliver these services without being disrupted," he said.

Professor Peter Newman says it's cities in western countries - like Australia and the US - which have most to worry about if a new oil crunch happens.

He welcomes recent Australian government funding for rail infrastructure, but says a national plan of action needs to be drafted and implemented.

"We really do need a national peak oil strategy that can take us through the next two decades of change in our infrastructure requirements," he said.

"I think that's something Infrastructure Australia can do [but] it will need political assistance and so it needs the public to get behind it.

"Every city will have to adapt but the Asian cities will be a lot easier to adapt ... they are already going to electric cars and they are building metros in 89 cities in China; 14 cities in India are putting in new electric rail metros ... they are recognising the need as did Japan many years ago that they have to get off oil.

"They really are far less vulnerable to facing peak oil than are the American and Australian cities, but I do believe the American cities are highly vulnerable and will struggle to survive in many parts ... in this next decade."