Congratulations to Edgar Hertwich, Glen Peters and the  NTNU team for presenting the ‘Carbon Footprint of Nations’ as a  politically relevant way of accounting for greenhouse gas emissions,  based on a sound methodology.

The publication and website comes at an important time – the decisive  climate policy negotiations in Copenhagen are only half a year away –  and it will be a useful input to this process. For both, producers and  consumers, as individuals, companies and nations are responsible for  emissions and both have a joint responsibility to address the problem  with determination. The burden of this responsibility must be shared,  only then can a meaningful and comprehensive deal to cut global  emissions be achieved. The exact nature of this sharing is yet to be  determined in negotiations but it is certainly useful to provide the  viewpoint of both, production-based and consumption-based emission  inventories.

The work is also important from a methodological point of view.  Whilst it is, of course, not the first publication to present findings  from an environmentally extended multi-region input-output (EE-MRIO)  model (numerous other researchers and the authors themselves have driven  forward this field of research), it clearly emphasises the  applicability and usefulness of this method. The consistent combination  of existing, mostly standardised, environmental and economic accounts  and the unambiguous allocation of impacts to consumption categories are  the strengths of EE-MRIO. It is also an acknowledgement that  international trade is the key element in separating production from  consumption in a globalised world and that the complex trade  relationships need to be addressed in a methodological sound manner.  Clearly, much more needs to be done to make the method robust enough for  political target setting. An upcoming report from the recent European  EIPOT project makes suggestions on methods, data and institutions to  develop EE-MRIO in that direction (www.eipot.eu).

Looking at greenhouse gas emissions from a consumption perspective is  politically significant and addresses arguably the most important  environmental challenge faced to date. But it cannot provide the full  picture of relevant impacts and it will be necessary to monitor other  indicators alongside the carbon footprint, such as the ecological  footprint, water footprint and results from more specialised ecological  impact models, informing about biodiversity, ecosystem health and other  categories.

I wish the ‘Carbon Footprint of Nations’ website plenty of attention  and hope it helps in conveying the message of consumption-based  accounting.