Greenhouse emission ‘gap’ explained

Scientists at the University of Bristol say data on the five most abundant hydrofluorocarbons (HFCs) – used in refrigerators and air conditioners – show that almost half of the global emissions originate from non-reporting countries.

Professor Ron Prinn from the Massachusetts Institute of Technology, who leads the AGAGE network – which has been measuring the composition of the global atmosphere continuously since 1978 – said: “This study highlights the need to verify national reports of greenhouse gas emissions into the atmosphere. Given the level of scrutiny these reports are under at the moment, it is vitally important that we improve our ability to use air measurements to check that countries are actually emitting what they claim.”

In the study, published in the journal Proceedings of the National Academy of Sciences, the team used HFC measurements from the Advanced Global Atmospheric Gases Experiment (AGAGE) and gas transportation models to evaluate the total global emissions of five major HFCs.

The results showed that the total CO2-equivalent emissions – a standard unit for measuring carbon footprint – increased from 198 million metric tons per year in 2007 to 275 million metric tons per year in 2012. When the team compiled the HFC data for the five most abundant HFCs, they found that the reported emissions from developed countries are consistent with the atmospheric measurements.

Research leader Mark Lunt, postgraduate student at the University of Bristol, said: “Any phase-out mechanism would likely be more stringent for the developed countries, but these results show that emissions from non-reporting countries are also highly significant.”