Waste and climate change

According to the Fourth IPCC Assessment Report (2007), one tonne of methane is 25 times more potent than carbon dioxide over 100 years.

The waste sector is responsible for about 3% of Australian and global greenhouse gas emissions. In Australia, 79% (of this 3% in waste emissions) is from landfill waste, with most of the remaining 21% coming from wastewater.

In Australia, the main sources of waste emissions are:

• Solid waste. 79% of emissions result from anaerobic decomposition of organic matter in landfills and generates methane
• Wastewater. 20.6% of emissions result from anaerobic decomposition of organic matter in sewerage facilities (including on-site systems such as septic tanks) during treatment and disposal of wastewater, generating mostly methane.
• Incineration. 0.4% of emissions (carbon dioxide) result from the incineration of solvents and clinical waste.

 

The problem with methane from landfill waste

The primary greenhouse gas produced by waste to landfill and wastewater is methane. Methane in the atmosphere can capture and retain about 21 times more heat than carbon dioxide. This means that while emissions from waste to landfill are relatively small, they cause more significant warming in the atmosphere than many times their amount of carbon dioxide. Other sources of methane contributing to global greenhouse emissions include cows, used in dairy and meat production.

The waste degradation process in landfills occurs slowly, and methane emissions continue long after waste is placed in landfill. Estimates in any year include a large component of emissions resulting from waste disposal over the preceding 50 years. This means that recent changes in waste management practices only impact reported methane emission levels over time.

 

How do greenhouse gas emissions cause global warming?

 

The problem with waste

Much of our rubbish is the result of wasteful consumption patterns and our heavy reliance on disposable and new items, with 90% of the products we buy being thrown away within the first six months of their life (including packaging). Most of these goods use a lot of energy and water to produce.

Further, our ever-increasing demand on and competition for natural resources only continues to increase with a growing global population and higher personal consumption and household debt levels in developed countries like Australia. As we respond to a changing climate with fewer available resources and growing demand for goods and services, the cost of making and buying the food and items we consume will increase. 

The leeching of landfill waste and wastewater (sewage) can also cause soil and water pollution. As our climate changes, we will face more extreme droughts and floods. In urban areas, heavy flooding will also cause an increase in water contamination from sewage and landfill waste.

To find out more about becoming waste-wise, visit the Waste-Wise Action Plan page. 

To find out more about climate change, visit the Climate Change section.