The Montreal Protocol agreement, established in 1987, played a crucial role in reducing the presence of harmful chemicals and pollutants that endanger the Earth's valuable ozone layer.
This reduction has allowed the restorative gas to replenish in the upper atmosphere. However, despite these efforts, Science Alert reported that there appears to be one detrimental chemical that has evaded regulation, potentially impeding the recovery of the ozone layer or posing a threat to its future well-being.
Bromoform Poses Threat to the Ozone Layer
Scientists from the University of Saskatchewan in Canada revealed that human activity is releasing a significantly higher amount of the organic solvent bromoform (CHBr3) than previously believed. While this compound is naturally produced by phytoplankton and algae, its regulation was never considered under the Montreal Protocol.
However, it is also a byproduct of chlorine used for water sterilization, highlighting the range of sources that humans can control. Accounting for these anthropogenic sources increases global levels of bromoform by nearly a third compared to previous estimates.
This rise in bromoform levels has implications for the ozone layer, which still requires utmost protection. When bromoform decomposes, it releases bromide, a substance that can contribute to ozone depletion in the lower stratosphere.
The published paper, titled "Anthropogenic Bromoform at the Extratropical Tropopause" published in the journal Geophysical Research Letters, states that bromoform has not been regulated under the Montreal Protocol due to its short lifespan and the large natural sources of the compound despite its ozone-depleting potential.
Identifying Anthropogenic Sources of Bromoform
Researchers highlight the significant contribution of anthropogenic sources to the transportation of the organic solvent bromoform (CHBr3) into the extratropical stratosphere of the Northern Hemisphere, Science Alert reported.
The concentration of these anthropogenic sources is primarily found along coastal areas due to industrial and energy production activities. The study suggests that emissions in the Northern Hemisphere could be increased by as much as 70.5% due to these sources.
The team combined existing data on emissions from ship ballast, power plants, and desalination plants and conducted simulations using various models, and found that the largest fraction of anthropogenic emissions come from global power plants, accounting for 10.3 to 25.9% of total CHBr3 emissions. Desalination and ship ballast water, on the other hand, contribute only small proportions.
The coastal regions of the Northern Hemisphere extratropics, particularly in Europe, North America, East Asia, and South Asia, are identified as the primary areas where anthropogenic CHBr3 emissions are concentrated.
Although emissions from oceanic sources like seaweed and phytoplankton still outweigh those from human activities, the study highlights the previously underestimated contribution of human-related sources and the absence of regulations to monitor bromoform emissions.
Due to limited field data and an understanding of the mechanisms of bromoform production, accurately estimating emissions from natural sources remains challenging. Nonetheless, the study underscores the significant role of human activity in bromoform emissions, which calls for further attention and potential regulatory measures.
Science Alert previously reported that the effectiveness of the Montreal Protocol in banning chemicals, like CFC's, and preserving the ozone layer as a crucial shield against harmful ultraviolet radiation from the Sun has been widely acknowledged. However, the findings of this study suggest that there may be a need to revise and update the agreement in light of new information.
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