Prices in Europe’s carbon emissions trading scheme have collapsed this year, in part because there were too many allowances in the system starting off, threatening the future of the whole market.

“Without intervention … Europe’s climate policy is over,” one analyst said. Some of Europe’s biggest energy and manufacturing firms also wrote a letter to the European Commission that called for Europe to take “decisive action now” to raise the price of carbon and fix the scheme.

The European Parliament’s environment committee voted in favor of temporarily cutting the number of emissions permits to be issued.

This year, the price of permits has fallen about 50 percent. Emissions allowances are now about 6 euros per ton—a four-year low, and about