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Thứ Năm, ngày 19/05/2022

Unsound management of chemicals and wastes underpins runaway climate change

08/01/2022

    With the eyes of the world on COP 26 on climate change, policymakers are urged to act in addressing “the elephant in the room” - pollution arising from emissions from combustion, chemical production and non-circular waste management.

    According to Mr. Rolph Payet - Executive Secretary of the Basel, Rotterdam and Stockholm (BRS) Conventions, the twin threats of climate change and biodiversity loss through increasing pollution from chemicals and wastes show no signs of slowing. COP 26 needs to address pollution reduction, including the life-cycle approach to the management of chemicals and waste, including plastic waste, to simultaneously slow the increase in greenhouse gases and lead to improvements in environmental quality and the recovery of nature. “Making peace with nature” is about stimulating and supporting the transition to a more sustainable global economy built upon circularity and a life-cycle approach to resource use. Since the sound management of chemicals and waste underpins all of the globally agreed Sustainable Development Goals (SDGs), it needs to also be addressed through strategies and policies addressing climate change as well”.

    A recent BRS Secretariat technical report, produced jointly with the Secretariat of the Minamata Convention on mercury, explores the profound interlinkages between climate change, chemicals and waste. Four main linkages are particularly pertinent to deliberations in Glasgow:

    First, petrochemical and chemical industries, with strong links to the fossil fuels sector, continue to be significant contributors to global greenhouse gas (GHG) emissions. Releases of GHG and hazardous chemicals happen at all stages in the life cycles of chemicals, including the production of input materials, primary and secondary production processes, chemical use and disposal. Hazardous chemicals and GHGs are release during everyday use of products including in agriculture through the application of pesticides, domestic refrigeration and air-conditioning, and specialist use in fire-fighting foams and explosion protection, to name just a few.

    Second, as we tackle issues of land degradation and food production as a result of climate change, adaption responses often lead to increasing use of chemical fertilizer, pesticides and plastics, to combat higher incidences of pest and disease outbreaks, as well as the need to create more micro-environments for agricultural production. Reports indicate increased distribution, growth and reproduction of pests at higher temperatures and in wetter conditions, which in turn leads to a reduction in the efficacy of pesticides. Pesticide usage as a result of both increased temperature and precipitation could rise by 1.1 - 2.5% by 2040 and by 2.4 - 9.1% by 2070 in China alone, despite current efforts to reduce pesticide usage. Robust strategies are thus required for pest and disease mitigation to avoid excessive growth in pesticide use.

    Third, climate change can lead to increased releases of hazardous chemicals into the environment. One example is that the melting of polar and alpine glaciers, permafrost and ocean ice induced by climate change results in releases of trapped hazardous chemicals, including persistent organic pollutants (POPs) and mercury. Projections suggest that under a high GHG emissions scenario, mercury emissions from permafrost could reach a peak of 1.9 ± 1.1 Gg Hg per year in 2200, the equivalent of current global atmospheric emissions. Furthermore, flooding and other hydrological impacts caused by the melting of sea ice and permafrost, sometimes compounded by increased precipitation, can lead to local contamination due to physical disruption and damage of pipelines and storage facilities, leading to oil and chemical spills.

    Fourth, increased mobilization and volatilization of chemicals from materials storage and stockpiles occurs as temperatures rise. An estimated that 240,000 tons of obsolete pesticides are stockpiled in Eastern Europe alone, and between 4 and 7 million tons of HCH isomers, generated as a by-product of the manufacture of the POP Lindane, have been stockpiled globally since the 1950s. Abandoned stockpiles of compounds containing heavy metals, which may include mercury, are also found in many parts of the world. Such stockpiles represent “ticking time-bombs” of chemical pollution in a world with rising temperatures.

    Regionally, such impacts are already beginning to be felt. In the Arctic, for example, trends of POPs have generally been decreasing due to measures introduced to reduce emissions and releases, both before and since the establishment of the Stockholm Convention. Now, however, some are levelling off, and even showing upward trends in air and biota in recent years, climate change being part of the reason. Some POPs, such as polychlorinated biphenyls (PCBs), are no longer declining in the Arctic to the extent that would be expected, given known decreases in their primary source emissions, possibly due to climate change. This would support model-based studies which suggest climate change will affect contaminant transport pathways to the Arctic.

Nam Hung

(Source: Vietnam Environment Administration Magazine, English Edition IV-2021)

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