I have the cover story this week in the dead-tree/living table TIME, on the future of oil (available here to subscribers). Gas prices have dominated the political conversation for weeks—at least until the Supreme Court started its health care hearings—and with the summer driving season just around the corner, the national obsession won’t be lift any time soon. Republicans and Democrats, oil executives and environmentalists have seized the opportunity to take potshots at each other, with one side claiming that more drilling will greatly ease the pain at the pump, and the other side arguing that energy efficiency and alternative energy are the only solutions. (I lean toward the latter.) The reason gas prices are so high, of course, is because oil itself is expensive, with Brent crude over $125 barrel. And that’s largely because oil markets are spooked over possible conflict with Iran, which could take one of the world’s major crude suppliers offline—and potentially block the Strait of Hormuz, through which 20% of the world’s oil flows.

Still, even fear of war in the Middle East doesn’t really explain why oil has remained so expensive as demand from the world’s biggest consumer—the U.S.—has been falling and the global economy remains sluggish. That fact—along with evidence that production of conventional oil seems to have plateaued a few years ago—has renewed fears that the world is approaching something like peak oil. The worry is that these high prices could just be the beginning, a signal that our thirst for oil is finally exceeding our supply. “The fact is that most of the world’s oil wells are in decline,” says David King, the former chief scientific adviser for the British government and the co-author of a recent Nature paper on oil supplies. “The only way to keep supply up is through the heroic discovery of new oil reserves.”

But as I write in my cover story, those heroic discoveries are occurring around the world, from the deepwater finds off Brazil to the North Dakota tight oil that has led to a resurgence of American crude production. There are oil sands in Canada and new resources in the melting waters of the Arctic. There will be oil—and that may be the problem.

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That’s because the new supplies are for the most part more expensive than traditional oil from places like the Middle East—sometimes significantly so. They are often dirtier, with a greater risk of more devastating spills and accidents. The decline of major conventional oil fields—coupled with the rapidly rising demand from countries like China and India—means the spare production capacity that once cushioned prices is melting away, ushering in an era of volatile market swings. And there’s climate change—burning all this leftover oil could lock the world into dangerous warming. “I’m less concerned about the absolute disappearance of fossil fuels than about the environmental consequences of pursuing what’s left,” says Michael Klare, an energy expert and the author of The Race for What’s Left.

It’s not all bad. Many of these new sources are found in the U.S. That’s already translated into an economic boom for oil producing states like Texas and especially North Dakota, where the unemployment rate is a miniscule 3.2%. As the U.S. pumps more oil at home and imports less foreign crude—down to 45% of liquid fuels—the country effectively saves money, keeping more of the billions we spend on gasoline here at home. It’s also good for energy security—the U.S. already imports less than 1.9 million barrels a day from the Persian Gulf, and new sources like the oil sands of Canada and deepwater in Brazil mean we’ll at least be importing crude from friendlier countries. Given the role that Mideast oil money has played in the spread of Islamic fundamentalism and in the power of authoritarian petrostates like Russia, a shift to new producers is largely a good thing. “We’re seeing rapid and major changes in the geopolitics of oil,” says Fatih Birol, the chief economist of the International Energy Agency.

But even significantly greater U.S. production won’t guarantee lower gas prices. Oil is a global commodity, and major demand from the developing world will likely keep prices high everywhere. And all this oil will come with a cost. Mining Canadian oil sands, for instance, can be extremely destructive to the local environment, causing deforestation that takes years to recover from. Oil sands crude is also more energy-intensive than conventional oil, with a greenhouse gas footprint that is 10 to 15% larger on a wells-to-wheels basis. And of course by effectively extending the age of oil, unconventional crude will cook the planet if we really do burn it all. “20th century oil is not 21st century oil,” says Deborah Gordon, an expert at the Carnegie Endowment for International Peace. “New unconventional oil is going to recarbonize global petroleum supplies.”

There’s more—but you have to subscribe. Read this week’s cover story on the future of oil here.