5.4 Waste and climate change

Summary

This module discusses the significant link between waste management and climate change, emphasizing the role of methane and nitrous oxide emissions from landfills and wastewater. It highlights the underestimated impact of waste on global greenhouse gas emissions and explores potential reduction strategies, including landfill gas recovery, waste diversion, and recycling. The script also introduces carbon trading mechanisms like the Clean Development Mechanism (CDM) and the emerging Nationally Appropriate Mitigation Actions (NAMA), showcasing examples of successful waste management projects in reducing emissions.

Takeaways

• ♻️ Climate change is primarily caused by human activities that increase greenhouse gases, such as carbon dioxide, methane, and nitrous oxide.
• 🌡 Methane is 25 times more potent than CO2, and nitrous oxide is 298 times more potent in warming the Earth over a century.
• 🌐 Greenhouse gases are often measured in terms of CO2 equivalents to standardize their impact.
• 🌑 Black carbon, resulting from incomplete biomass combustion, is a significant but currently unquantified climate pollutant.
• 🔥 Burning waste is a typical source of black carbon, which is a topic of growing interest and research.
• 🗺️ The waste sector contributes 3-5% of global greenhouse gas emissions, mainly through methane from landfills and wastewater.
• 🌱 Waste management, including recycling and reducing waste transport, could potentially reduce global greenhouse gas emissions by 10-20%.
• 💡 Landfill gas recovery and electricity production are effective ways to mitigate greenhouse gas emissions.
• 🌿 Composting, anaerobic digestion, and thermal processes can reduce emissions and substitute other resource-intensive processes.
• 💼 Carbon trading mechanisms like the Clean Development Mechanism (CDM) allow countries to earn carbon credits for emission reductions, including waste management projects.
• 🌍 NAMAs (Nationally Appropriate Mitigation Actions) are voluntary commitments by countries to reduce emissions, with financial assistance from developed nations.

Q & A

What is the primary cause of global warming and climate change?

The primary cause of global warming and climate change is the increase in average global temperatures, mainly due to human activities that increase greenhouse gases such as carbon dioxide, methane, nitrous oxide, and other industrial gases.

How does methane compare to carbon dioxide in terms of its potency as a greenhouse gas?

Methane is 25 times more potent as a greenhouse gas than carbon dioxide over a 100-year period.

What is the role of black carbon in climate change?

Black carbon, resulting from incomplete combustion of biomass, is an important short-lived climate pollutant. It is typically produced by burning waste and contributes to climate change, although it is not yet included in the quantification of greenhouse gas emissions due to the lack of a standardized comparison metric.

How does the waste sector contribute to global greenhouse gas emissions?

The waste sector contributes to global greenhouse gas emissions primarily through methane emissions from landfills, methane and nitrous oxide from wastewater treatment, and minor CO2 and nitrous oxide emissions from the burning of fossil fuels.

What is the estimated percentage of global greenhouse gas emissions that could be reduced by the waste management sector?

It is estimated that around ten to twenty percent of global greenhouse gas emissions could potentially be reduced by the waste management sector through various measures.

What are some methods to reduce greenhouse gas emissions from waste management?

Some methods to reduce greenhouse gas emissions from waste management include landfill gas recovery, diversion from landfills through composting or anaerobic digestion, thermal processes, and waste minimization, recycling, and reuse.

How does carbon trading work in the context of waste management projects?

Carbon trading involves purchasing emission reduction credits or allowances from other sources, such as waste management projects in low and middle-income countries, which have mitigated emissions of CO2 equivalents. Mechanisms like the Clean Development Mechanism (CDM) allow projects in developing countries to earn carbon credits that can be used by industrialized countries to meet their emission reduction targets.

What is the significance of the Doña Juana landfill project in Bogota, Colombia?

The Doña Juana landfill project in Bogota, Colombia, is one of the largest Clean Development Mechanism projects in Latin America, which started in 2009 and was fully operational by the end of 2010. It has significantly reduced greenhouse gas emissions, with a total reduction estimated to be 14.8 million tonnes of CO2 equivalent over its 22-year lifespan.

What is NAMA and how does it relate to waste management?

NAMA stands for nationally appropriate mitigation action, which refers to a set of policies and actions that countries undertake voluntarily to reduce greenhouse gas emissions. It includes a wide range of actions such as policies, strategies, research, development, training, and capacity building, and can involve waste management projects as part of the efforts to reduce emissions.

Why is the contribution of the waste sector to greenhouse gas emissions considered to be underestimated?

The contribution of the waste sector to greenhouse gas emissions is considered to be underestimated because certain aspects of waste management, such as the benefits of recycling or reducing transport of waste, are not fully considered in the current quantification methods.

What is the global average contribution of the waste sector to greenhouse gas emissions?

The global average contribution of the waste sector, including wastewater, to greenhouse gas emissions is only 3-5%. However, this figure is believed to be an underestimate.