"Unless we price carbon predictably on a trajectory that gets us at least to [a] $75 average price per ton of carbon in 2030, we simply don't create the incentive for businesses and consumers to shift," she said. The world's second biggest emitter, the United States, for example is unlikely to establish a national price on carbon given stiff political opposition to carbon taxes and 'cap-and-trade' systems. Whether the U.S. opts to impose a carbon cost through regulation and rebates rather than through tax or trade, that should not matter. She cited the IMF's proposal for a carbon price floor and the proposal floated by Germany of a 'carbon club' of the world's biggest economies, which would coordinate how members measure and price carbon emissions and enable cooperation in slashing emissions in the largest industrial sectors. Reporting by Simon Jessop, Seham Eloraby, Valerie Volcovici; Editing by Katy Daigle and Toby ChopraOur Standards: The Thomson Reuters Trust Principles.

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