German Chancellor Angela Merkel called on Saturday for the European Union's Emissions Trading System (ETS), the bloc's flagship policy to cut greenhouse gas emissions, to become a global system. Thousands of power plants, factories and airlines in Europe have to surrender an allowance for every tonne of heat-trapping gas emitted. However, a surplus of allowances has depressed their price on the ETS and has made it cheaper to burn coal than to switch to greener fuels. "This instrument would of course be particularly effective if we could introduce it beyond Europe because then we'd have the s