CRUNCH time for the Kyoto protocol is fast approaching. 2012 marks the end of the two-year period during which rich nations must prove that they have cut emissions from 1990 levels. That may be an impossible task.
The problem lies with error bars. Matthias Jonas at the International Institute for Applied Systems Analysis in Laxenburg, Austria, has calculated that countries can only report their emissions to within 5 to 10 per cent of what they actually emitted (Climatic Change, DOI: 10.1007/s10584-010-9914-6). This is because there is no direct way of measuring how much carbon dioxide, say, a country emits.…
