A recent World Bank report on waste management and climate change co-authored by our moderator Perinaz Bhada-Tata estimates that current waste management methods, specifically emissions from landfill, account for almost five per cent of total global greenhouse gas emissions and 12 per cent of the world’s emissions of methane (CO4), a greenhouse gas with an impact more than 20 times that of carbon dioxide (CO2).

According to the Clean Development Mechanism (CDM) and Joint Implementation (JI) of the Kyoto protocol, there is a great potential for addressing methane emissions by reducing the amount of waste that ends up in a landfill. Globally nearly 70% of our solid waste is landfilled, a meagre 19% is recovered through composting or recycling, the remaining 11% is converted to energy through incineration or other waste-to-energy technologies.

With aggressive measures for reducing landfilling put into place more than 1000 Mt of CO2-eq could be averted by 2030, costing less than $100 per ton of CO2-eq per year.

There are multiple technological options to reduce GHG emissions from post-consumer waste. Composting can eliminate greenhouse gas emissions from landfill, and reduce overall GHGs from solid waste. It is the organic material in landfill that produces methane. Contrary to the decomposition that happens in a landfill which emits methane, composting is aerobic, which emits carbon dioxide which has comparatively lesser green house gas potential per atom of carbon emitted. Offsetting this, the use of compost in agriculture increases carbon sequestration, decreases the need for irrigation by as much as 70%, and also reduces the need for chemical fertilizers. We will discuss composting in depth in a future panel.

Waste-to-energy via combustion is another option with potential for climate change mitigation. There are over 800 of these plants worldwide, producing electricity and district heating for the community by incinerating waste. For example, Switzerland, Japan, France, Germany, Sweden and Denmark are countries in which 50% or more of the waste that is not recycled is sent to an incinerator, reducing the amount of waste that is disposed of in landfills to as little as 4% of the overall waste generated. Some of these countries have passed legislation to prohibit future landfilling of combustible waste.

While there is wide consensus about the waste hierarchy, which positions waste-to-energy at just one step above landfill in relation to sustainable long-term options, waste-to-energy is often promoted as the primary option for reducing post-recycled waste landfilling. Post-recycled waste is the residue after all possible formal and informal recycling has been carried out.
This panel will discuss the following questions:

  1. Renewability of waste-to-energy and its climate change mitigation potential
  2. Is there a need for the rest of the world to focus on waste management as a climate change mitigation method as it is a low hanging fruit. Technologies which can help mitigate climate change due to waste management already exist.
  3. Highest potential for climate change mitigation within waste management – recycling, composting, waste-to-energy or landfill? (not getting into the reuse-reduce discussion, that will be a different panel)
  • Perinaz Bhada-Tata

    Co-author of World Bank’s What a Waste

    Perinaz Bhada-Tata is the Co-author of World Bank’s What a Waste – A Global Review of Solid Wast...
  • Nickolas Themelis

    Prof. Nickolas Themelis is the Founder and Director of the Earth Engineering Center at Columbia Univ...
  • Paul Brunner

    father of material flow analysis methodology in urban metabolism

    Prof. Paul H. Brunner is considered to be the father of material flow analysis methodology in urban ...
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