Emission profiles from the foam and refrigeration sectors comparison with atmospheric concentrations. Part 2: results and discussion

The modelling of consumption and emissions of ozone depleting chemicals and greenhouse gases has been a challenge for the communities of both the Montreal and Kyoto Protocols. One of the particular challenges has been the representative modelling of consumption in sectors with substantial delays in emission and the resulting accumulation of ‘banks’. Several experts, including the authors of this paper, have been active in building databases of sources over the last 5 years and have continued to refine estimates as new information has come to light. The decision of the Inter-Governmental Panel on Climate Change to commission a Special Report on factors influencing the interface between the two Protocols has acted as a stimulus to draw conclusions from the current state of knowledge. This paper is the product of this initiative as it relates to two key sectors of delayed emission: refrigeration equipment and insulating foams. As the title indicates, the paper documents the development of consumption, banks and emissions for both sectors and uses these to develop estimates of anticipated atmospheric concentration. These estimates are then compared with measured atmospheric concentrations in order to evaluate the appropriateness of the modelling approaches used and to identify areas where discrepancies remain. Efforts have been made to explain these discrepancies wherever possible, but it is recognised that the process remains one of continuous refinement. The major findings of the work are that emissions of refrigerants and foam blowing agents will continue well beyond the scope of the current study (1990–2015), with banks of 2.5 and 3 million tonnes, respectively, remaining at 2015. However, the composition of each bank is very different because of the more rapid turnover in the refrigeration sector led by higher emission rates and shorter product lifetimes. This means that the CFC component of some blowing agent banks may provide a significant target for reducing climate change impact of future emissions where technical and economic criteria are met. For the refrigeration sector better containment, recovery at end of life, re-use or destruction, but also change of refrigerant are the key options. There is clear evidence that the atmospheric concentration predictions for those fluorinated compounds predominantly used as blowing agents are less certain. This is partially because of the high dependence of the prediction on the emission functions assumed during the long use phase. A small variance can have a significant impact on the outcome. There are also continuing uncertainties about end-of-life scenarios for major market sectors such as the US domestic refrigerator sector. These areas are the focus of continuing study.