LONDON - Western governments are proving astonishingly slow to face up to the four-pronged energy crisis that lies ahead and which could in due course engulf them:

World consumption of fossil fuels is soaring when it should be falling.

Dependence on supplies from politically unreliable and unstable regions is increasing when it was meant to be diminishing.

Carbon emissions from burning fossil fuels are expanding worldwide when they should be shrinking.

Investment in alternative energy sources is at best marginal, with the one really major source of clean energy, nuclear power, being held back in most countries by political pressures.

All these trends are heading the wrong way, and their effects may unfold on different (and maybe quite unexpected) time scales. World oil consumption is officially 80 million barrels a day, compared with 60 million in 1980. But the real figure could well be higher, some say as much as 84 million barrels a day. Without radical policy changes, world consumption will be 122 million barrels a day within two decades, the International Energy Agency says.

The second crisis springs from the first. By 2030, the energy agency estimates, more than half the world's supplies will originate from shaky and troubled regions. But events will not wait until then.

Two decades ago Margaret Thatcher was dismayed to learn that 14 percent of Western Europe's gas imports were from the Soviet Union. Today, 40 percent comes from those regions, and the upheavals in Ukraine, which is crossed by pipelines carrying much of this huge volume, give a whiff of what is to come.

As for oil, consider the sources of what are supposed to be huge future supplies. Iraq sees its pipelines blown up almost every day. Iran may yet be the scene of another war. Saudi Arabia is under attack and wobbly, and unease runs through most of the other Gulf states. The Russian oil industry is in turmoil, and in other Central Asian producers and the various pipeline transit states like Georgia and Ukraine, the political landscape is generally volcanic.

Nigeria has strikes and sabotage, Sudan is at war, Venezuela is politically unsettled and Algeria still has a bad dose of Islamic fanaticism. Libya may be on the path of virtue, but it is too early to be confident. The golden age of North Sea oil and gas is drawing to an end, and Britain will shortly become a net importer once again.

The prospect might be manageable if governments were all set firmly on the path to a cleaner and greener energy future.

Europe has tried, with high taxes and the new system of carbon emissions "trading" - though even in Britain, carbon emissions rose last year, when they should have been falling, and the government now reluctantly concedes that its goals for emissions reductions are being missed.

But these noble efforts are dwarfed by opposite pressures elsewhere. China is building 60 new coal-fired stations a year. America is still relying on coal for over half its electric power while drinking more oil than ever, helped by gas-guzzling SUV's. Energy issues received hardly a mention in the recent elections.

Acres of giant wind pylons, the current Great Green Hope, cannot conceivably fill the gap.

The one obvious alternative, nuclear power, remains largely stymied by politics. China may have bold longer-term plans for new plants. But elsewhere, nuclear programs have been in limbo for years. In Britain, a pioneer in civil nuclear power, the policy is to phase out nuclear capacity altogether, though the nuclear option is still claimed to be "open."

Yet the plain truth about the world's energy future is that the massive electric power that industry and 21st-century life need will have to come increasingly from nuclear energy if it is not to come from coal, oil and gas. The experts know this, as do the technicians. But do the politicians dare to break the news to a still nervous public, or will they wait until the lights go out, industry seizes up and governments are bundled from office by angry and frightened voters?

Advisers to President George W. Bush are said to be warning him that America needs a radically new energy policy. They are right. So do we all.

Lord Howell, a former British energy secretary and president of the British Institute of Energy Economists, is Conservative spokesman on foreign affairs in the House of Lords.