A Transition to Zero Waste Unlocking the Climate, Economic, and Social Co-Benefits of Waste Sector Transformation
As the climate crisis intensifies, the urgency of reducing greenhouse gas (GHG) emissions has never been greater. Among the various sources of emissions, the waste sector often remains underestimated, despite being the third-largest source of anthropogenic methane emissions globally. Methane, a potent greenhouse gas with over 80 times the warming potential of carbon dioxide (CO₂) over a 20-year period, is largely generated in the waste sector from decomposing organic matter in oxygen-limited environments such as landfills. The methane mitigation potential within the waste sector is significant and can be deployed fast and with small investments compared to interventions in other sectors, and thus poses a unique opportunity for climate action in the short term.
The Role of the Waste Sector in Greenhouse Gas Emissions
The importance of the potential impact of methane abatement has been reflected in initiatives such as the Global Methane Pledge signed in 2021, the ROW (Reducing Organic Waste) Declaration launched at COP29 and many other regional and national policies. These instruments provide a positive framework to raise ambition in climate action, and need to be translated into practice. The waste sector contributes approximately 20% of anthropogenic methane emissions, making it a significant driver of near-term climate change (UNEP and CCAC; 2021). Municipal solid waste (MSW)—especially food scraps, garden clippings, and paper products—is the primary contributor. In some regions, landfills are even the leading source of methane emissions.
Food and green waste pose a unique accessible opportunity for methane mitigation globally. Diverting organic waste from landfills through source separation, separate collection and processing through any of the diverse techniques for this waste stream – such as animal feed, composting, anaerobic digestion, cultivation of black soldier fly- should thus be a priority in waste management planning. Studies show that composting alone could reduce MSW methane emissions by 78%. When combined with bio-stabilization of residuals and biologically active landfill cover, reductions can reach as high as 95% (Tangri, N. et al; 2022).
These impacts can also extend to others if connected to overall food systems transformation, by connecting urban discards with food production through agroecological practices. Preventing food waste avoids emissions not only from decomposition but also from the production, processing, and transport of food. Globally, one-third of food produced is wasted, accounting for up to 10% of GHG emissions (Gikandi; 2021).
As reducing methane emissions becomes a global priority and national and local governments enact policies to address this, and international financial institutions increase their support to methane mitigation in the waste sector, it becomes imperative to keep a perspective of the big picture and avoid trade-offs between methane and other GHG emissions. A recent study analyzes the long-term global warming effect of three waste management strategies -waste disposal in dumpsites and landfills, incineration and zero waste- in three cities: Lagos, Nigeria; Barueri, Brazil; and Quezon City in the Philippines. The three waste approaches are compared by modeling temperature outcomes by 2060. In the three cities, zero waste (including practices such as source separation, separate collection collection and treatment of organic discards and recyclables) outperforms waste disposal and incineration. In Lagos, Nigeria and Quezon City, Philippines, the avoided warming resulting from zero waste interventions is up to nine times bigger than incineration (Ribeiro-Broomhead, J. and Tangri, N; 2025).
Moreover, measures taken in the waste sector have an impact that extends to the overall material economy. Seventy percent of global GHG emissions stem from the lifecycle of material goods—from extraction and manufacturing to disposal (Fraser, M. et al; 2024). These emissions are often categorized under industrial, agricultural, and energy sectors, but waste generation and management decisions directly influence them. Strategies like waste prevention, reuse and recycling reduce the need for virgin material extraction and energy-intensive manufacturing. This has a ripple effect across multiple sectors, amplifying the mitigation potential of waste management well beyond its direct footprint. As calculations show, zero waste systems can lead the waste sector to become a net negative source of greenhouse gas emissions (Tangri et al; 2022).
Transitioning to a Zero Waste Approach
Zero waste is an approach to waste prevention and management that differs from linear waste management in its essence. Zero waste is both a vision and a strategy. Defined by the Zero Waste International Alliance as “the conservation of all resources by means of responsible production, consumption, reuse, and recovery of products, packaging, and materials without burning, and with no discharges to land, water, or air that threaten the environment or human health,” it emphasises systemic change away from disposal-dependent economies. As a vision, zero waste understands waste as a symptom of a broader systemic problem, and envisages a world where nothing and no one is wasted.
On a practical level, zero waste encompasses a combination of policies and programs that align with the waste hierarchy and can be organised by 5 overarching strategies:
Set the goal to end waste disposal in dumps, landfills, and incinerators. This provides a long-term vision and goal to direct policies and programs.
Industrial responsibility over production, accountability and redesign of products to minimise waste at source, design products for reusability, longevity, repairability, toxic-free, and alternative delivery systems.
Reorient consumption patterns around ecological limits. Promote values among society not based on material consumption but on solidarity, empathy and care for family, friends and the environment.
Develop systems and infrastructure to safely recover resources at their highest and best use, avoiding harmful and toxic processes. This includes setting up systems for separate collection, reuse, composting, anaerobic digestion, use of black soldier fly reuse, recycling discards.
Ensuring social and environmental justice by respecting and engaging all sectors on the frontlines of the resources ecosystem, with prioritisation of the sectors most impacted by waste generation, such as local communities, waste pickers, and other waste workers.
Zero Waste Around the World
Zero waste is not theoretical—it is a practical approach. Over 550 municipalities worldwide are taking steps to transition to zero waste across diverse economic, cultural, and climatic contexts.
Zero waste provides a framework that is suitable to be adapted to diverse contexts, as the experience from around the world shows. Thiruvananthapuram, the capital of the state of Kerala in India, with a population of almost a million, runs a highly successful decentralized zero waste system. The program includes an intensive program for organic waste, which represents 72% of the total municipal solid waste in Kerala. This includes promotion of source separation and separate collection of organic waste, extensive community outreach and education programs, and promotion of on-site treatment that greatly reduces waste collection. As part of this, the government provides subsidies to set up small-scale organic waste treatment units such as compost systems, micro-anaerobic digesters, bins, etc. These schemes achieved compliance rates for source separation of 80% in the residential sector and 88% in the commercial sector within five years (Ramachandran, K; 2019).
In Slovakia, the municipality of Partizánske has also implemented a decentralized system for organic waste which combines promotion of home composting for single-family households, and door-to-door separate collection of organic waste for apartment buildings. This program resulted in 95% of single-family households currently composting at home and a 18% city-wide reduction of residual waste since 2018. Moreover, this has had a positive impact on the public budget, bringing savings in waste management. (Moňok et al; 2024). 19 municipalities in Europe have been certified as Zero Waste Cities by Mission Zero Academy and dozens more are in the process to achieve the certificate.
In Tanzania, the organization Nipe Fagio has introduced the zero waste approach that is rapidly expanding throughout the country. Starting in 2019 in Bonyokwa ward in Dar es Salaam, the organization put in place a zero waste system that prioritizes community engagement, cooperative-led separate collection and decentralized waste management. The program has been instrumental to create a zero waste cooperative that handles separate waste collection, build a materials recovery facility to process dry-recyclables, composting of organics, cultivation of black soldier fly and a vegetable garden, develop a transparent fee payment system through an app that connects users and collectors, and intensive community awareness and engagement campaigns. The program has a source separation compliance rate of 95% and a composting, reuse and recycling rate of 85%. It is a hallmark of the implementation of context-grounded waste management system, and has not only expanded to other wards within Dar es Salaam but is also being replicated in Zanzibar and Arusha, with materials recovery rates of 82% in Zanzibar, and 75% in Arusha (Nipe Fagio, 2024).
Furthermore, the implementation of zero waste systems is faster than the processes to set up centralized technology such as landfills or incinerators. Based on their long-term experience, Zero Waste Europe estimates the average period for a municipality to implement a zero waste plan is between 2-3 years. In Dar es Salaam, the zero waste system implemented by Nipe Fagio in Bonyokwa achieved 95% compliance in source separation and reduced waste disposal by 75% in just two years. In San Fernando, Pampanga, Philippines, the zero waste plan boosted waste diversion from 12% to over 80% in six years. Sălacea, Romania went from near-zero recycling to 40% in only three months. Parma, Italy increased separate collection from 48.5% to 81% in seven years (Tangri et al, 2022, Nipe Fagio; 2024).
Co-Benefits of Zero Waste
Beyond reducing GHG emissions, zero waste generates a wide spectrum of environmental, social, and economic co-benefits. One of the most compelling co-benefits of zero waste systems lies in their potential for job creation and boosting local economies. The job creation hierarchy mirrors the environmental hierarchy: the strategies that are most beneficial for the environment also generate the most employment. According to a global study covering 16 countries, zero waste approaches—ranging from repair and reuse to composting and recycling—create significantly more jobs than disposal-based systems such as landfills and incinerators. For instance, repair activities generate an average of 404 jobs per 10,000 tonnes of waste managed, recycling creates 115 jobs, and remanufacturing generates 55. In stark contrast, incineration and landfilling produce only about 1–2 jobs for the same volume (Ribeiro-Broomhead, J. & Tangri, N.; 2021).
Moreover, zero waste jobs are often more diverse and higher quality than those in disposal systems. Employment opportunities range from technical roles in electronics repair and remanufacturing to community outreach, data analysis, and urban farming using compost. These jobs not only enhance local economic resilience but also support social equity by providing livelihoods to marginalized groups. Job creation opportunities in global south countries also mean possibilities to recognize the work of waste pickers and integrate them into formal waste management systems through contracts, provision of infrastructure, payment for their services and integration in the overall planning and implementation of waste management. This alignment of environmental and economic goals highlights zero waste as an ideal investment for building resilient local economies.
Conclusion
The waste sector’s role in methane and GHG emissions is both a challenge and an opportunity. Left unchecked, waste continues to fuel climate change and degrade ecosystems. Yet, with the adoption of zero waste strategies, the sector can become a net-negative source of emissions while generating substantial social and economic gains.
Zero waste is no longer an aspirational goal; it is a proven, scalable solution. As cities, governments, and industries grapple with the dual crises of climate change and unsustainable resource use, zero waste offers a transformative pathway—one that reduces emissions rapidly, enhances resilience, and creates thriving, just societies.
For environmental services professionals, business consultants, research organizations, community based organizations, and international development associations, the message is clear: zero waste is not simply about managing garbage—it is about rethinking systems, reclaiming resources, and redefining progress.
The stakes of inaction are too high to remain passive. It is time to bring commitments into action and to replicate successful systems that are operating across the world. The know-how is there, grounded in very diverse contexts, often lying in communities, waste pickers and zero waste champions. We encourage all waste management practitioners and governments to raise ambition and put zero waste at the center of climate action.
Global Zero Waste Cities
Program Lead (GAIA)