A new study shows how circular waste management systems can help to curb emissions of greenhouse gases and air pollutants.
In the first global study of its kind, researchers from the International Institute for Applied Systems Analysis, University of Natural Resources and Applied Life Sciences examined the waste sector in 184 countries and regions.
The team translated the Shared Socioeconomic Pathways (SSPs) – a set of scenarios describing alternative socioeconomic developments up to 2100 – into waste narratives and evaluated the potentials to reduce greenhouse gas and air pollutant emissions by contrasting baseline and mitigation scenarios until 2050.
Adriana Gómez-Sanabria, lead author and a researcher in the IIASA Pollution Management Research Group said the study looks at future trends of municipal waste generation and analyses the impact on greenhouse gas emissions and air pollution if waste management systems were to be maintained at the current state until 2050.
The amount of municipal solid waste generated globally every year has grown exponentially over the last decades. A third of the global trash every year is generated by about one sixth of the population. However, only about 13 per cent is recycled and 5.5 per cent composted. The absence of suitable treatment facilities to cope with the quantities of waste often results in environmental and health impacts, including emissions of toxic pollutants and greenhouse gases.
“Subsequently, we evaluated to what extent it would be possible to reduce waste and associated emissions when implementing circular waste management systems under the different SSPs. This approach also helps us to understand how different world developments hinder or accelerate the level and pace of adoption of the circular waste management system and the implications on emissions,” Gomez-Sanabria said.
A circular waste management system is a sustainable system in which waste generation is minimised, waste collection schemes reach the entire population, open burning of waste and littering is eliminated, waste is diverted from landfills, materials are reused and recycled, and as a last resort, refuse is efficiently incinerated to generate energy.
Researchers found that the sustainability scenario (SSP1) – a scenario that envisions a world that emphasises more inclusive development that respects environmental boundaries – could bring major and earlier co-benefits compared to scenarios in which inequalities are reduced but pollution control measures focus on treating pollutants in a separate process after they are produced. In this scenario, the researchers estimate it would be possible to eliminate open burning of waste before 2050, thereby eradicating this source of air pollution.
While it will not be possible to completely eliminate methane and CO2 emissions from municipal solid waste, researchers point out that based on the fact that the maximum technical abatement potential globally is assessed at about 205 Tg of methane in 2050 – where 1 Tg = 1 million tons – the reduction of emissions from municipal solid waste could ultimately account for almost a quarter of this. This highlights the need for fast and bold action to reduce and divert waste from landfills, increase reuse and recycling, and to promote technologies with carbon capture and storage.
The researchers estimate that the lowest quantities of solid waste generation are expected in SSP3 where countries focus on achieving energy and food security goals within their own regions at the expense of broader-based development.
According to the authors, waste reduction together with the adoption of circular waste management systems will deliver a broad range of co-benefits including reduction of greenhouse gas emissions, air and water pollution, while also supporting the realisation of the Sustainable Development Goals (SDGs).
“We are confident that our detailed representation of the municipal solid waste sector and associated emissions and mitigation potentials can be applied to develop emission scenarios for the Intergovernmental Panel on Climate Change (IPCC),” Gomez-Sanabria said.
“Our work can also be used to support regional and local scale air- and water pollution studies, and inform local and national governments about the likely developments, environmental consequences, and mitigation opportunities in the municipal solid waste management sector.”
For more information, visit: iiasa.ac.at