Up in the air

摘要

It is hardly surprising that climate discussions tend to gloss over uncertainties in data on greenhouse-gas emissions. Governments are struggling towards an international agreement to reduce those emissions, and their focus is necessarily on coming up with specific, enforceable targets. But the fact is that scientists' ability to measure emissions and verify that countries are following through on their commitments is far from adequate. And that is unlikely to change without the full engagement of governments and scientists.rnThere are a number of reasons to be sceptical about current emissions data (see page 18). Some are a matter of human frailty: it is often in the best interests of both companies and governments to underestimate emissions, and thus to overstate the effectiveness of a given technology or policy in reducing them. That temptation will only increase as countries ramp up climate commitments. Other reasons, however, hinge on the uncertainties inherent in even the best emissions statistics.