25 Jun 2019

How waste adds to our carbon footprint

Posted in: Reducing emissions

How waste contributes to our carbon footprint – within our businesses and at home

We all know waste is just waste-ful (pun intended). It fills our landfills, pollutes our environment, and uses up our finite natural resources. But what is not so well known is that what we stick in our rubbish bin contributes to our carbon footprint. (Editors technical aside: we will stick with the ‘bin’ focus so we’re referring to solid waste.)

How waste contributes to your carbon footprint

In 2017 the total emissions from the waste sector in NZ were 4124.7kt CO2e, and solid waste contributing the majority of that (about 90% or 3,724.5kt CO2e). The emissions from solid waste are equivalent to the emissions from powering over two million homes each year!

So, what exactly is solid waste?

Solid waste is usually what we think of in a landfill. Paper (recyclable and non-recyclable), nappies and sanitary products, plastics, organics (think food waste), metals, glass, construction and demolition waste, textiles, rubber and other potentially hazardous materials. There are three types of landfills. Currently, most of New Zealand’s household and commercial waste is placed into our managed municipal landfills. The other significant types are non-municipal (think industrial fills that dispose of construction and demolition waste) and farm fills (used for disposal of household and other on-farm waste to land).

Solid waste contributes to our collective carbon footprint through what happens once it gets to landfill. When breaking down with the help of microbes (specifically methanogenic bacteria) in the oxygen-free environment, solid waste releases methane, carbon dioxide and smaller amounts of nitrogen (all greenhouse gases). As these bacteria decompose the organic matter into smaller components, methane and carbon dioxide are released as by-products. Different types of waste create different amounts of greenhouse gases; paper, timber, organic waste and textiles are some of the highest contributors to emissions. (Geek fact: there’s quite a fascinating process of how the populations of different methanogens change over time in the landfill if you ever want to google it).

So, if you’re wanting to tackle carbon emissions in your home or work, where should you start?

Well, look in your bin! Gain an understanding of the types of materials that are being thrown away so you identify areas to work on.

At work, can you reduce the amount of products you buy in the first place, or re-use the waste instead of throwing it out? If you can’t reduce or reuse, can you recycle? Even better, can you use your influence to request less packaging from suppliers or partners? These are a few questions to ask both at work and at home to start setting some goals. They can be as simple as making sure you get the correct bins (if you do not have these already) and educating your team around how to use them best. Raising awareness of these issues with staff in your workplace can also make them more aware of waste they are producing at home – bonus!

At home, have you got a recycling bin? Is there an option for organics collection at your house, or in your community, through the council? Have you considered a compost bin or worm farm? Can you ask for less packaging when you buy something from the store (this sends a strong message back to the supplier and manufacturer)?

Mackenzie country Zero Waste Strategy

A more ambitious step could be to create an Impacts and Aspects Register where you consider what your organisation is bringing in and throwing out, in a systematic way. Having a waste audit performed by a third party can give you a strong baseline to work from, or there are also some great resources to help you complete a waste audit, like Recycle.co.nz.

Quick tip:

Use the three ‘R’ principles: Reduce, Re-use and Recycle. You can also add in the other ‘R’s; Refuse (do not accept the packaging in the first place) and Rot (compost where you can).

Some landfills are able to capture the greenhouse gases to use as an alternative energy source, rather than wasting it. Find out more in our Landfill Gas Energy Carbon Credit Projects summary.