No country has yet declared that it is going to war over oil but the world has already seen altercations in which oil is the undeclared pretext for military action. Some are ongoing. Others are pending.

Oil, of course, is the energy that fuels modern civilization, and every industrialized nation is wholly dependent on it. Entire economies, material security and even military might are all founded on an adequate supply of oil. Indeed, a generous supply of oil has been the foundation of the industrializing process that constitutes our modern world. Constrict oil supplies and countries get nervous.

The formation of the OPEC cartel in the 1970s and its tightening of supplies motivated many industrialized nations to move for more control of supplies: some drilled for their own, others negotiated secure trading arrangements such as NAFTA. Now, as a rising global demand for oil comes closer to reaching global supply, the stakes of gaining or losing power are shifting countries toward the military option.

The American invasion of Iraq was never officially an oil war but nothing else explains the intervention. Iraq had no terrorists to threaten the West. Saddam Hussein was one of many dictators who might have been deposed using a humanitarian pretext. The country had no weapons of mass destruction. But it does have one of the largest untapped sources of oil in the world. As Alan Greenspan, the former chair of the US Federal Reserve said, the war in Iraq was "largely about oil". And Paul Wolfowitz, former deputy to the US Secretary of Defence, admitted the same in June, 2003 (Ronald Wright, What is America? A Short History of the New World Order ).

Oil is now implicated in the ongoing hostilities in Afghanistan, confirmed by the announcement that a proposed $8 billion, 1,680 km pipeline is to transect the country for the purpose of moving gas and later oil from vast supplies in Central Asia to Pakistan, India and then to tankers for shipment to thirsty Western countries. The stated purpose for fighting the Taliban now has a sub-plot – vital energy must move from Turkmenistan, Uzbekistan and Kzakhstan to provide oil security to the West. A secondary purpose is to undermine the growing strategic importance of Russia as a major supplier of energy to an increasingly vulnerable Europe.

The latest skirmish in this energy drama was Russia's invasion of Georgia. Military strategists refer to the incident as a "warlet". Warlet or otherwise, it was intense, bloody and destructive. Russia's stated justification for the invasion was to protect the citizens in the breakaway regions of South Ossetia and Abkhazia. But the real reason was geopolitical.

Three major pipelines run through Georgia, bringing energy from Azerbaijan to central Turkey. One of these pipelines was scheduled to be enlarged and extended in 2010. The Nabucco project was to connect westward to Austria, bypassing Russia and reducing its economic leverage on Europe. Russia's move in Georgia essentially ends the Nabucco project, curtails an extra million barrels per day of oil from reaching Europe, and solidifies Russia's Gazprom monopoly as the major provider of European energy ‹ the 40% proportion is expected to rise to 50% by 2020. The Russian move extends its sphere of influence and gives it enhanced energy control over the EU, one of the world's most powerful economic and military regions.

China is using the same strategy in Africa as it curries the favour of corrupt regimes in order to win oil rewards for its soaring demands. The rebels in Nigeria know they can exert huge political leverage by attacking oil installations and threatening tight international oil supplies. Al-Qaida would love a chance to disable any major oil or gas installation in the Middle East or elsewhere on the planet.

Geopolitical tension is also increased by the trend of countries ‹ Venezuela is a prime example ‹ to nationalize oil resources, thereby giving priority to their own interests rather than serving the international marketplace. This is disadvantageous to large, wealthy consumers of imported oil, such as the USA. The trend further politicizes oil and heightens the likelihood of conflict over shortages.

Meanwhile, as Arctic ice melts and hundreds of thousands of square kilometres become accessible for oil and gas extraction, tension is building between Canada, Russia, America and any northern country with possible claims to this new energy frontier. Russian submarines have flagged the North Pole. Canadian and American ice-breakers are under construction, Canada's aerial territorial patrols have increased and its official Northern presence is being enhanced. Any legitimate or dubious means of claiming territorial rights is warming up the North beyond mere climate change. Complex and tense diplomacy will rise as countries negotiate for critical new energy resources.

This is now the world in which we live. And it looks increasingly dangerous given the acute dependence of countries on tightening oil resources.

One of the important ways of defusing this danger is to lessen demand by reducing oil consumption. If the threats of climate change are not justification enough for becoming more energy efficient and for shifting to renewable sources, then consider the geopolitical incentive.

Geopolitical tensions will only increase as oil and gas supplies become more scarce in a world of rising demand, soaring population and expanding economic activity. If environmental reasons are not motivation enough for using less oil, then think peace.