International. Using atmospheric measurements, the authors of a recent study published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS), have discovered that the total CO2 equivalent emissions of the five most common HFCs from countries where it is required to provide detailed annual reports to the United Nations Framework Convention on Climate Change (UNFCCC), increased from 198 (175-221) Tg-CO2-eq⋅and-1 in 2007 to 275 (246-304) Tg-CO2-eq⋅ and-1 in 2012 (+39%).
These GWP emissions correspond to those reported in the Unfccc over this period, and indicate that the gap between reported emissions and global HFC emissions from atmospheric trends is almost entirely due to emissions from unreported countries.
However, their estimates based on the measurement of individual HFC species suggest that the most abundant HFC country emissions from reporting countries: HFC-134a, were only 79% of the unfccc's total inventory, while other HFC emissions were significantly higher than reported values. These results suggest inaccuracies in reporting methods for individual HFCs, which appear to cancel when added together.
The researchers also found the largest increases in emissions of HFC-32 and HFC-125, which – as components of the R410A and R407C – are increasingly used in air conditioning units. These two HFC emissions have increased by 63% and 44% in developed countries, and by 166% and 100% in developed countries during the same period.
