The European Parliament on Tuesday approved a rescue plan for the European Union’s system for trading carbon-emission credits. The lawmakers hope to revive prices for carbon credits, which have been so low that the system is creating few incentives for smokestack industries to cut back on their emissions of greenhouse gases.

Although many experts see the plan as little more than a stopgap action, “today was extremely important to get the first emergency measures started,” said Marcus Ferdinand, an analyst at Thomson Reuters Point Carbon, a market research firm in Oslo. “This shows the European Union cares about its emissions trading scheme.”

The approval by the Parliament in Strasbourg, France, had been widely expected, and the carbon-credits market reacted only modestly. The price of a carbon allowance ticked up about 10 euro cents, to 4.90 euros, before settling back to about €4.80, or $6.60.

Europe’s Emissions Trading System, begun in 2005, is the largest and most ambitious effort yet to use markets to regulate greenhouse gases. Under the program, businesses like steel mills and coal-fired power plants are required to obtain permits for their allowable emissions of carbon dioxide — authorizations they can assemble either through allocations from regulators or through auctions. Each allowance permits a company to emit one metric ton of carbon dioxide.