Professor David C. Wilson
Waste & Resources Management Consultant
Visiting Professor in Waste Management
Imperial College, London

Measuring black carbon emissions from open burning of waste

Black carbon (BC) emissions from the open burning of municipal solid wastes (MSW) 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. Natalia Reyna has just completed her PhD thesis at Imperial College London, co-supervised by Professors David C Wilson and Stephen R. Smith, with the aim of generating reliable data to plug that gap. Our second and final paper was published last week in the leading journal Atmospheric Environment, providing a reliable methodology for measuring emission factors (EFs) for black carbon from waste burning. i.e. how much black carbon is produced by burning a kilogram of waste. The Atmospheric Environment paper is available to download free of charge until 24 August 2019; the long-term link has a paywall.

When the measured emission factors are combined with our earlier measurements of the extent of open burning of municipal solid wastes in Mexico; other published estimates of waste composition and activity levels around the world; and a range of estimates of the global warming potential of black carbon as compared to CO₂; our best estimate of the contribution of BC from the open burning of MSW to global heating is in the range 2-10% of global CO₂Eq emissions. 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.

Hazardous Waste – Plus ça Change

CIWM President, and Chair of CIWM’s Hazardous Waste Special Interest Group (SIG), David C Wilson reflects in his August CIWM column on the challenges facing hazardous waste management in the UK and Ireland – past, present and future. His review with the SIG of current challenges suggests that not much has changed over the 44 years of his involvement with the hazardous waste sector. In particular, the UK continues to lack the ‘regulatory certainty’ which is necessary to secure the investment required in hazardous waste management infrastructure if such investment is left entirely to ‘the market’. And looking at the island of Ireland in particular, the uncertainties around Brexit do not help.

 

CIWM success in influencing policy

DCW’s Presidential year at CIWM continues to be dominated by marine plastics. As part of our efforts to influence developing UK policy in this area, CIWM and Wasteaid published a report: ‘FROM THE LAND TO THE SEA: How better solid waste management can improve the lives of the world’s poorest and halve the quantity of plastic entering the oceans’. His June CIWM column reports success: the day before the biennial Commonwealth Heads of Government Meeting in London in April, Theresa May announced a new Commonwealth Clean Oceans Alliance (CCOA) backed by a £61.4 million funding package of funding to help tackle marine plastics, of which more than £20 million would help developing country members of the CCOA improve waste management at a national and city level.

Uncontrolled burning of solid waste as a significant contributor to climate change

To qualify for inclusion in the official (IPCC) inventory of greenhouse gases (GHGs), data for an emission source must meet a quality threshold. This currently excludes black carbon emissions from the open burning of wastes. The relative quantities may be small compared to carbon dioxide from fossil fuels or methane from landfill, but black carbon is around 2,000 more powerful than CO₂ as a GHG and has an even shorter half-life than methane. In the absence of real data, early modelling studies using broad assumptions suggested that black carbon from open burning contributes 5% of total global GHG emissions, causing 270,000 premature deaths a year. DCW’s PhD student at Imperial College London, Natalia Reyna, has been working for the last four years to provide real data which would meet the IPCC requirements. Our first paper, published this month in the leading journal Environmental Research, presents field data from Mexico on how much solid wastes are disposed of by open burning, either by households or at uncontrolled dumpsites. The results suggest a GHG contribution from uncontrolled burning in backyards in Mexico fifteen times larger compared to methane released from the decomposition of equivalent amounts of waste in a disposal site. This suggests that urgent action is needed to reduce domestic open burning of waste and that this would have a significant impact, both on improving local air quality and respiratory health, and on reducing climate change. A future paper will present data on emission factors, i.e. how much black carbon is produced by burning a kilogram of waste.

Let’s Skip ‘The Tip’

Language matters. DCW’s March column for the CIWM Journal celebrates the dramatic improvements in waste and resource management that have been achieved since he first entered the sector in 1974. This is largely due to changes in public behaviour, which have enabled the UK, for example, to increase recycling rates over the last 20 years from just 6% to 46%. However, he questions how we can expect people’s mind set to change permanently when some local authorities, and both professionals and politicians, continue to refer to modern recycling facilities as ‘the rubbish tip’.

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Turning the Tide

DCW’s February column for the CIWM Journal focused on the topical subject of marine plastics. He reported back on ‘Oceans 21’, the latest Development Finance Forum organised by the German Development Bank KfW, where he led a workshop on marine litter. The conclusions were clear: the amount of plastics entering the oceans is at least an order of magnitude greater than estimates of the visible quantities in the oceans or on beaches – so the first priority is to ‘turn off the tap’. And the most effective way to do that is to extend municipal solid waste collection in developing countries to all people and to eliminate uncontrolled dumping and burning; our best judgement was that this could reduce the weight of plastics entering the oceans by 50-70%.