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 two papers have been submitted as evidence to the IPCC sixth assessment study due to be published in 2021.

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.
A short article reporting this research appeared in the September/October 2019 issue of CIWM’s new, award-winning magazine Circular.

DCW looks back on his CIWM Presidential year

Professor David C. Wilson’s final contribution to the CIWM Journal took the form of an interview in which he looked back on his Presidential year. This web-posting also includes an index of and links to his monthly columns for the CIWM journal, many of which were ‘think-pieces’ on issues in which he has been involved for years or even decades. Among the questions covered in the final interview were: has any topic dominated the year (yes, plastics – both marine plastics and the ‘China ban’); and what would be your advice to Enda Kiernan and future CIWM Presidents (‘Be true to yourself’ – which the editor also used as this month’s headline).
Interviews and DCW’s theme for the year:

  • Dec 2018: ‘Be true to yourself’. DCW looks back on his year as president. PDF attached at end of post.
  • Dec 2017: A key utility service. DCW revisited his Presidential address to further explain his key themes for the year ahead. The overarching theme was to have solid waste management recognised as an essential utility service.
  • Nov 2017: One small step. The editor Ben Wood introduced DCW, his story in waste and his hopes for his Presidential year. PDF attached at end of post.


  • Oct 2018: Plastics – diabolic or fantastic? How to respond to the crisis of plastics entering our oceans? Which plastic uses are diabolic and which fantastic?
  • Jun 2018: How to influence people. DCW reported on CIWM’s role in influencing the UK’s initiative on marine plastics which was announced at the Commonwealth Heads of Government Meeting in London in April 2018.
  • Apr 2018: China – coming full circle. In the wake of the current China-induced recycling crisis in the West, DCW gave his personal perspective on China’s journey in waste management and recycling over the last 30-40 years and moving forward…
  • Feb 2018: Turning the tide. Where do plastics entering the ocean come from, and how do we turn the tide?

Promoting waste reduction and recycling:

  • Sep 2018: Charge! DCW reflected on the challenges of devising the right policies to charge households for solid waste management services
  • May 2018: Revaluing recycling. DCW argued that we need to rethink recycling if it is to become sustainable and proposed a framework for doing so, by considering the embodied social, environmental and technical values alongside the market price.
  • Jan 2018: Inspiring reuse. DCW showcased the five inspiring projects shortlisted for Best Reuse or Waste Prevention Project at the CIWM Sustainability and Resource Awards 2017.

Waste and climate

  • Jul 2018: Don’t waste our climate. DCW made the case for resource and waste management as an entry point to achieve significant climate mitigation. The article was subsequently re-published by the National Solid Waste  Association of India (NSWAI) in their member journal Waste Monitor in July 2019.
  • Website May 2018: Uncontrolled burning of solid waste as a significant contributor to climate change. DCW reported on current research at Imperial College London.

Tackling the global waste crisis

  • Website Nov 2018: DCW awards his Presidential Medal to Mike Webster, Founder and CEO of the charity Wasteaid.
  • Website Oct 2018: Tackling the global waste crisis through community waste management. DCW reported on two papers in the peer-reviewed literature, which follow-up on the CIWM-Waste aid toolkit Making Waste Work.
  • Dec 2017: A key utility service. A key theme for DCW’s Presidential year was to highlight the global waste crisis, the 3 billion people who lack access to basic SWM services.
  • Website Nov 2017: DCW launches toolkit for community waste management. Introducing DCW’s Presidential Report, the CIWM-Wasteaid Toolkit Making Waste Work. The Toolkit includes a dozen How-to-do-it Guides to enable local entrepreneurs to implement simple technologies using organics and low-value plastics in the waste.

Other DCW areas of interest or ‘hobby horses’:

  • Aug 2018: Hazardous waste – plus ça change. DCW reflected on 40 years of involvement with hazardous waste policy, and concluded that the current and future challenges identified by CIWM’s Hazardous Waste Special Interest Group have changed relatively little over the years.
  • Mar 2018: Let’s skip “the tip”. DCW argued that terms such as “the tip”, “rubbish”, “refuse” and arguably “tipping”, have no place in the vocabulary of the professional waste and resource manager.

Don’t waste our climate

In his July column, CIWM President David C Wilson makes the case for more investment in resource and waste management as an ‘entry point’ to achieve significant climate mitigation. The sector already has a track record in developed countries, with methane mitigation from landfill since the 1970s, and both methane mitigation and recycling making a major contribution to meeting Kyoto Convention greenhouse gas (GHG) reduction targets between 1990 and 2010. But that early success also means that the IPCC’s 2010 assessment is that the ‘waste’ sector only contributes 3-5% to current GHG emissions. DCW argues that this is a gross underestimate which fails to consider: the current emissions from uncontrolled burning; historical reductions; contributions across the economy from recycling; and waste prevention (particularly food waste).  The results suggest that better resource and waste management has the potential for reducing GHG emissions across the World economy by 15, 20 or 25% or even more. Such numbers may be guesstimates, but whatever number we choose to use, the message is still the same. Further investment in this sector, in both developing and developed countries, is a major political priority in order to meet our climate targets.

This article was subsequently re-published by the National Solid Waste  Association of India (NSWAI) in their member journal Waste Monitor in July 2019.

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.