Black carbon from burning waste has “significant climate impact”

picture credit: WasteAid UK

Carbon emissions resulting from the black carbon produced by open burning of waste has a “significant climate impact”, new research finds.

Research undertaken by Imperial College suggest black carbon emissions from open burning of waste has a climate impact equivalent to 2–10% of global CO2Eq emissions.

Global black carbon CO2Eq emissions from burning waste are 2-8 times larger compared to methane (CH4) CO2Eq emissions arising from the decomposition of equivalent amounts of combustible biodegradable waste disposed at dumpsites, the research found.

Black carbon is a particularly serious air pollutant emitted from the uncontrolled burning of waste in open fires because it has a global warming potential up to 5,000 times greater than carbon dioxide (CO2) and is also linked to detrimental health impacts.

The research suggests action to reduce open burning of waste would have a “significant and immediate benefit to improving air quality and reducing the potential impact on climate change”.

Open burning

Open burning is a widely practiced method of solid waste disposal in many regions of the world and represents a significant source of air pollution.

However, few quantitative measurements of black carbon from open burning have been completed to establish the extent and impacts of this emission source on the environment.

Emission factors for black carbon from burning mixed solid waste samples were measured in the laboratory based on waste compositions in a representative developing country (Mexico).

Black carbon emission factors were also derived for individual waste types, including: green waste, different types of plastics, textiles and paper and cardboard.

“Given the associated air pollution and health impacts, urgent global action is essential to eliminate open burning of waste; this will provide a relatively ‘quick win’ in tackling the global climate emergency.”

Individual waste black carbon emission factors were combined using waste composition data from different areas of the world to estimate regional and global black carbon emissions from this source.

Currently, two billion people globally have no waste collection at all and the waste of over three billion people is either dumped or subject to uncontrolled burning.

Uncollected waste and open dumping in the coastal towns and cities of developing countries could also be contributing more than half of the plastics entering the oceans.

Co-supervisor of the paper and CIWM past president Professor David C Wilson said in a blog post on the topic: “Black carbon emissions from the open burning of municipal solid wastes and other waste types contribute significantly to global heating but are not yet included in the official IPCC inventory of greenhouse gases (GHGs) due to poor data availability.

“Given the associated air pollution and health impacts, urgent global action is essential to eliminate open burning of waste; this will provide a relatively ‘quick win’ in tackling the global climate emergency.”

Black carbon

Chemically, black carbon is a component of fine particulate matter. Black carbon consists of pure carbon in several linked forms.

It is formed through the incomplete combustion of fossil fuels, biofuel, and biomass, and is emitted in both anthropogenic and naturally occurring soot.

Black carbon has recently emerged as a major contributor to global climate change, possibly second only to CO2 as the main driver of change. Black carbon particles strongly absorb sunlight and give soot its black colour.

Primary sources include emissions from diesel engines, cook stoves, wood burning and forest fires.

Reducing CO2 emissions is essential to avert the worst impacts of future climate change, but CO2 has such a long atmospheric lifetime that it will take several decades for CO2 concentrations to begin to stabilise after emissions reductions begin.

In contrast, black carbon remains in the atmosphere for only a few weeks, so cutting its emissions would immediately reduce the rate of warming, particularly in the rapidly changing Arctic, according to the Centre for Climate and Energy Solutions.

The paper, which was published in the journal Atmospheric Environment, is available to download free of charge until 24 August 2019.

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