Reducing climate change impacts on waste systems

In response to the climate emergency, cities around the world are already implementing ambitious actions to reduce emissions (mitigation), alongside efforts to increase their climate resilience (adaptation). These measures are put in place to protect citizens and infrastructure against current and future extreme weather events. Of C40 cities, 97% are already experiencing the effects of climate breakdown. The main climate hazards cities are reporting include storm and wind, flooding, sea level rise, extreme heat, drought and landslide.

It is crucial that the investments cities make in the transition towards zero carbon are resilient to the current and future climate and extreme weather events. Cities failing to integrate climate change adaptation into investments in clean energy, buildings, transport, waste and other key sectors risk mal-investment and missed opportunities. Early consideration of climate hazards and potential responses can therefore reduce risk for building owners and does not necessarily need to add cost to projects.

How does climate change impact waste management?

Waste management is one of the key services every city government provides, and climate change can impact waste facilities both directly and indirectly. At the same time, improper waste management – e.g. waste blocking drainage exacerbating flooding during rainfall events can reduce the ability of a city to cope with extreme climate events. All new and existing waste management systems therefore need to be designed to be resilient to climate change. The following table demonstrates the impacts climate change brings on the collection, processing and disposal stages of waste management systems.

Examples of climate change adaptation measures integrated in waste management systems

Extreme weather events

• Frequent collection at scheduled times (based on extreme weather forecasts) reduces risk of waste bags sitting at the curbside for too long and being carried away into streets or waterways by heavy rainfall, heavy wind, landslides or snow.
• Frequent collection is possible when shorter routes are designed making use of multiple decentralised transfer stations.
• Covered collection trucks and underground waste containers prevent waste from drifting away with extreme wind.
• Disposal sites must be compacted each day to force waste disposed to settle, preventing deadly landfill slides (most dangerous for communities living off waste salvaged in or around dump sites).
• Emergency recovery plans in place and up to date to cover a full range of weather events projected over the lifetime of the specific waste infrastructure.
• Landfill leachate collection system planned with enough capacity for heavy rainfall events.
• Extreme weather events generate a lot of waste from single use emergency equipment (water bottles, tents, plastic sheets, etc). Adapting these materials to be biodegradable or easily reusable and recyclable means lowering the impact of such disasters in a city’s systems.
• Extreme weather events often generate immense amounts of debris waste from buildings as well as other destroyed materials and landscapes. Establishing a disaster waste management plan helps prepare cities for these extreme waste loads and better plan for recycling materials.
   

Drought

• Diverting organic waste from landfill through segregated organics collection contributes to preventing landfill fire outbursts.
• Fire-safety structures for landfills, including periodical cover with dry material.
   

Sea level rise

• Ensure the location of new waste disposal sites – historically close to rivers – is not vulnerable to sea level rise projected over the lifetime of the site.
   

Extreme heat

• Decentralised organic waste treatment plants (such as composting and anaerobic digestion) to reduce transporting distances, increase organic waste recovery and reduce risk of dumpsite fire.
• Decentralised waste transfer stations to allow for smaller waste collection vehicles and shorter trips for each worker, especially when the city relies on a labour-intensive system.
• Implement frequent organic waste segregate collection, distributing food waste caddies (reduces odours, pest and insects from rapidly degrading material) and promoting home composting where collection is not present.
• Scheduled collection: waste can be put outside only in a 2 hour buffer from the scheduled time of collection to avoid insects, pests (as well as risk of waste bags being carried away by extreme events).
• Protected and well aerated sorting facilities for resource salvagers/waste pickers to sort waste.
• Install water fountains across the city to reduce consumption of disposable bottles that steeply increase during heat waves.
   

Flooding

• Prevent waste blocking the drainage system by achieving universal waste collection and reducing litter by placing segregate street bins and promoting educational campaigns.
• Ensure landfill has more than one access route and effective drainage systems.
• Ensure waste transfer stations, disposal sites and storage areas are elevated and safe from floods, for example avoiding flood plains (low-lying near rivers or coastal areas) and develop adaptation plans for established sites located in flood areas.
• Aerated elevated or closed curbside collection containers.
• Adopt a post-flood action plan: floods will carry large quantities of waste that will end up in the open once the water level lowers down; cities should have a plan in order to quickly collect it and divert as much as possible, and to safely dispose of the residual waste.

C40’s Adaptation and Mitigation Interaction Assessment (AMIA) tool

To help cities understand the interactions and interdependencies associated with climate change adaptation and mitigation actions, C40 Cities produced the AMIA tool. The tool is designed to support city practitioners in climate action planning by mapping the synergy potential, trade-off potential, mal-investment risk and piggybacking opportunities of a wide range of actions, such as switching to electric buses and investing in building-scale solar energy. It also includes 60 case studies and examples of city initiatives that have aimed to maximise synergies and address interdependencies. You can download it and find out more about how it works here.

COVID-19 and municipal solid waste systems

The COVID-19 health crisis has placed immense stress on municipal solid waste systems worldwide, from dramatically changing waste generation patterns, to requiring new collection and recycling protocols to ensure worker safety, particularly for informal waste pickers who saw income disappear with enforced lockdowns. The pandemic has reinforced how critical it is to make municipal systems resilient to the stressors and shocks caused by external events such as a global pandemic or the climate crisis. Solid waste systems and Zero Waste efforts are resilient when mature markets for secondary resources, reusable products and repair services are ensured, strengthened by risk assessments, adaptation plans, and the inclusion of the informal and private sectors as central components. Read more about COVID-19 and waste systems here.

City Case Studies

Waste Management to prepare for and prevent flooding

Durban (South Africa): The City has evaluated the interdependence of flooding events with different urban sectors and implemented an early warning food forecast system. In the event of a potential flood, settlements and infrastructures along the river, such as wastewater works, pump stations, substations and road crossings, are notified. Additionally, in Durban’s stream management programme in townships, the city has worked with local cooperatives to clear out rivers, by removing waste and alien vegetation. Left unattended, these blockages cause significant cascading impacts to adjacent communities during periods of increased rainfall and flooding. The City is now also looking to quantify the impacts of these interventions and to formulate a business case for similar programmes for all of its streams and rivers.

Social inclusion of waste collectors to reduce flooding

Accra (Ghana): The City of Accra won The Future We Want Engages All Citizens award at the 2019 C40 World Mayors Summit for this project, and is inspiring other African cities looking to follow this example. The city developed a policy to recognise waste pickers as active players in waste collection, assigning them with collection in low income areas, where private companies do not collect waste. As a direct result, in a little over six months the city improved collection rates by about 10%, increased recycling three-fold and is saving approximately US$ 5 million per year compared to what it would cost to collect and dispose of the waste by a private company. Accra is a city prone to flooding which is often even worsened due to uncollected waste blocking urban drainage systems. This project contributes to removing waste from blocked drainage systems by waste pickers and reducing flood risk.

Organic waste as reforestation fertilizer

Rio de Janeiro (Brazil): The City’s long standing hillside reforestation programme, has planted over six million seedlings on 2,200 hectares of land within the city limits since the 80’s. Reforestation aims to reduce landslides and the impacts of flooding, creating local job opportunities as well as lowering urban temperatures. Through an internal cooperation with the City’s sanitation department, the City has been using the mixed solid waste collection stream as source of compost fertilizer for the reforestation projects. Under this cooperation, a minimum of 1.100 m³ of compost is to be sourced from solid waste annually.

Climate-ready waste collection

Washington D.C. (United States): Washington D.C.’s Department of Public Works announced the changing of waste collection times during heatwaves, and encourages people to only leave trash and recycling outside after 6.30pm. Starting waste collection earlier in the mornings or later in the evenings not only reduces the exposure of workers to heat, but also avoids waste being stored too long outside during hot temperatures.

Sources:

https://www.c40knowledgehub.org/s/article/Reducing-climate-change-impacts-on-waste-systems?language=en_US