After two weeks of negotiation, the United Nations climate conference in Dubai agreed last week to “transition away” from fossil fuels. Left unanswered is whether governments are supposed to do that by reducing supply, reducing demand or both. A lot rides on the answer, but neither would affect the climate much.

In the demand-side scenario, technology saves the day with cost-competitive renewables. This is the vision of the International Energy Agency, according to which the more rapid the transition from fossil fuels, the more precipitous the decline in fossil-fuel prices. In its “Net Zero Emissions” scenario, oil demand drops faster than supply this decade, pushing oil prices below $30 a barrel soon after 2030, which corresponds to $1-a-gallon gasoline.

Yet even with fossil-fuel prices near historic highs, effective renewable substitutes are nowhere near cost-competitive. They’d have to get cheaper still to compete with $30-a-barrel oil. And in developed countries, especially the U.S., it’s impossible to get permits quickly enough for the staggering amount of renewable capacity that would be needed.

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In the supply-side approach, governments would slash oil production or impose rationing, hoping to make fossil fuels so expensive that renewables are the only option. This is the dark vision of “Stop Oil” and Greta Thunberg. But as long as renewable substitutes aren’t immediately available and oil and gas remain necessary, a small reduction in supply causes prices to soar. That means windfall profits for energy companies, scarcity for everyone else, and electoral danger for the governments responsible. Ms. Thunberg claims that climate change is a “death sentence” for the poor, but the poor are far more vulnerable to disruptions in energy supply. In the 1970s, an oil boycott aimed at the U.S. caused famines in Africa.

While the stop-oil view was popular at Dubai, there were enough adults in the room to keep the conference from committing to it. “There is no science out there, or no scenario out there, that says that the phaseout of fossil fuel is what’s going to achieve 1.5 C” (the Paris Agreement’s proposed limit on 21st-century temperature increases), said conference president Ahmed al Jaber, “unless you want to take the world back into caves.” Saudi Energy Minister Abdulaziz bin Salman dared countries to try to choke off the oil supply: “Let them do that themselves. And we will see how much they can deliver.”

Poor countries are clear-eyed about the danger of energy poverty. “We are not going to compromise with the availability of power for growth,” said India’s minister for power, R.K. Singh. China has more coal plants under construction than are in operation in the U.S. Few rich countries have announced plans to stop drilling for oil or gas, and none of those are major producers. Even President Biden ran away from increasing the gasoline tax as soon as prices went above $3 a gallon in the summer of 2021.

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The administration’s answer to this conundrum is to defer political consequences via the regulatory state. The Environmental Protection Agency has proposed to require that all coal and natural-gas plants shut down or adopt unproven zero-carbon technologies by 2038. Another EPA proposal would require 62% of all cars sold in America to be fully electric by 2032.

Assuming they survive court challenges and future administrations, they would impose soaring prices and reduced mobility on Americans. They would have almost no impact on global temperatures unless other countries, including China and India, also commit to energy poverty. The question is how much damage these policies will do before they’re abandoned.