CO2 value collapse hits trading scheme Governments must act to save the clean development mechanism (CDM), a UN panel has reported. Under the CDM projects such as wind farms and the distribution of efficient cookers and lights, countries earn carbon credits for CO2 emissions avoided. The scheme, created by the UN after Kyoto, has been undermined by the global recession and eurozone crisis so that the credits have fallen in value from $20 (£12.30, €15.50) a tonne in 2008 to $3 today. In addition, over-supply has devalued surplus credits to €1 ($1.30, £0.80) a tonne under another UN scheme permitting credit trading. As a result, many potential projects are not commercially viable and financiers and developers have shied away.