United Nations carbon offsets for December fell to a record as the European Union proposed a ban on carbon credits from emerging economies.

UN Certified Emission Reductions for December fell 4.2 percent to 1.36 euros a metric ton as of 2:02 p.m. on London’s ICE Futures Europe exchange. The futures contract for March also dropped to its lowest-ever price, declining 2.4 percent to 1.20 euros a ton, and the December 2013 contract weakened 1.9 percent to 1.55 euros, also a record.

Prices slid after the EU proposed to ban the use of UN Emission Reduction Units in its carbon market from April 2013, raising the possibility that countries would try to sell more offsets before the ban comes into effect.

To contact the reporter on this story: Alessandro Vitelli in London at avitelli1@bloomberg.net

To contact the editor responsible for this story: Rob Verdonck at rverdonck@bloomberg.net