First of all, multinationals have complex schemes for deciding where to operate and carbon tax is only one -usually small, seldom significant- among many factors considered in business relocation. Political and macroeconomic stability, market size, ease of doing business, transport infrastructure... all these count more than a potential carbon tax on decisions to relocate.

Secondly, if you count and cap emissions of a business sector globally you actually encourage businesses to shift these global emissions to where it is cheapest to spew them. And, my argument goes, counting emissions at a business sector level creates dilemmas over, e.g. how much should shipping be allowed to emit globally compared to the beverage industry. Does that matter?

Moreover, establishing a global cap on emissions for each multinational is not practical because some companies grow naturally while others die out. Deciding on a global cap per unit of output/ value added for a category of goods or services (that is what a business sector ultimately is) puts poor and less technologically advanced countries at a disadvantage far beyond problems with relocation.

I have a different suggestion: China is the largest emitter of greenhouse gases in the world. Half of its emissions are related to exports. Now think about European importers fo Chinese goods. Establish a carbon tariff, increase the prices of goods made in China with the cost of their carbon footprint (global or EU price level) and charge this to the final European user -if final consumption picks up the tab, which is the case with carbon taxes.

Opinions?

Counting CO2 emissions globally is not enough, it could be considered a start but it really gets us no where. What is the use of simply counting the emissions of a business sector globally, it does nothing to reduce those emissions without something beyond the counting, either cost of CO2 credits or taxes on emissions.