Saudi Arabia is highly dependent on oil exports, which account for most of the government’s budget. Last year, when prices peaked, the kingdom’s oil revenue swelled by 37 percent, to $281 billion, according to Jadwa Investment, a Saudi bank. That was more than four times the 2002 level. At one point in 2008, the average gasoline price in the United States surpassed $4 a gallon.

Saudi exports are expected to drop to $115 billion this year, after oil prices fell. American gasoline prices are hovering around $2.50 a gallon.

The one-year swing in the kingdom’s revenues shows that oil prices are likely to be a bigger factor in Saudi Arabia’s future that any restrictions on greenhouse gases, said David G. Victor, an energy expert at the University of California, San Diego.

Mr. Victor dismissed the Saudi stance as a stunt, saying that the real threat for petroleum exporters came from improvements in fuel economy and rising mandates for alternative fuels in the transportation sector, both of which would reduce the need for petroleum products. “Oil exporters have always, in my view, far overblown the near-term effects of carbon limits on demand for their products,” Mr. Victor said. “For the Saudis this may be a deal-breaker, but the Saudis are not essential players. In some sense, one sign that a climate agreement is effective is that big hydrocarbon exporters hate it.”

A recent study by the International Energy Agency, which advises industrialized nations, found that the cumulative revenue of the Organization of the Petroleum Exporting Countries would drop by 16 percent from 2008 to 2030 if the world agreed to slash emissions, as opposed to the projection if there were no treaty.

But with oil projected to average $100 a barrel, the energy agency estimated that OPEC members would still earn $23 trillion over that period.

Mr. Sabban, however, cited an older study by Charles River, a consulting firm, which found that the losses in revenue for Saudi Arabia alone would be $19 billion a year starting in 2012.