The 1987 Montreal Protocol, widely regarded as the most successful international environmental accord, has been effective in phasing out chemicals that harm the ozone layer and lead to health issues like skin cancer. Studies led by MIT indicate that this reduction in harmful substances is aiding the recovery of the stratospheric ozone, potentially returning to 1980 levels by 2040. However, the Protocol allows the use of ozone-depleting substances as feedstocks for other materials, assuming minimal atmospheric leakage. Recent observations reveal higher-than-expected emissions, prompting scientists, including MIT researchers, to assess the impact of feedstock leakage on ozone recovery.
Researchers found that increased leakage rates, if unaddressed by the Montreal Protocol, could postpone ozone recovery by seven years. Susan Solomon, an MIT professor involved in the initial research linking chemicals to ozone depletion, noted that feedstock chemicals pose a significant issue. Although global production of ozone-depleting substances has nearly ceased, they are still used as feedstocks to create other chemicals. A recent paper in Nature Communications quantifies the impact of leaked feedstocks used in making plastics and nonstick chemicals, stressing the need to curb emissions as the production of end products is expected to rise.
Stefan Reimann from the Swiss Federal Laboratories for Materials Science and Technology emphasized the importance of tightening emissions from industrial processes to maintain the Protocol’s success. Susan Solomon questioned the necessity of the exemption for feedstocks, given the discontinuation of other harmful practices. The study included contributions from researchers across various institutions, highlighting the widespread concern over the issue.
The discovery of the ozone hole over Antarctica in 1985, which allowed increased ultraviolet radiation to reach Earth, spurred the creation of the Montreal Protocol. The treaty, involving 197 countries and the EU, restricted CFC use. Initially, emissions from feedstocks were thought to be minor, but recent findings suggest otherwise. The Advanced Global Atmospheric Gases Experiment (AGAGE), co-founded by MIT’s Ronald Prinn, has revised leakage estimates to 3.6 percent, higher than previously believed.
The study compared different scenarios of feedstock leakage, revealing that a 3.6 percent leakage rate would delay ozone recovery, with emissions leveling off by 2045 and only halving by 2100. If leakage is reduced to 0.5 percent or eliminated, recovery could occur by 2066 or 2065, respectively. The findings underscore the need to reduce emissions from feedstocks either by stopping their use, switching chemicals, or minimizing leakage.
Susan Solomon expressed confidence in the chemical industry’s ability to adapt to the findings, suggesting alternatives exist to current feedstocks. Raising awareness of the issue is crucial, as AGAGE’s ability to detect feedstock emissions highlights the progress made in curbing other sources. The Montreal Protocol members meet annually to discuss topics like feedstock emissions, with potential mitigation strategies on the agenda. “We wanted to raise the warning flag that something is wrong here,” Western said.
Original Source: news.mit.edu
