How Do Recycling And Composting Fight Climate Change?

Although recycling and composting reduce the number of GHGs we put into the atmosphere, eliminating waste completely is even better. When we use reusable dishes, cutlery, etc. we eliminate the need to manufacture new stuff. The amount of energy required to wash a dish is much less than the energy required to make a dish, even if that dish is made of recycled materials.

Either "diversion" or "reduction" works here.

Although a lot of CO2 and even some CH4 are released in the composting process, scientists consider composting a good way to reduce GHGs. There are two main reasons for this: first, the most common alternative to composting -- landfill -- generates many times more CH4 (28 times as powerful a GHG as CO2); and second, the CO2 released in the composting process is not considered to be adding to the GHGs in the atmosphere, simply because it is part of the natural carbon cycle. With respect to that last point: all organic materials decay eventually, and the carbon they contain is released into the atmosphere as CO2. Fossil fuels are different, because they had been locked away underground for millions of years, so burning them releases "new" carbon, which increases CO2 levels in the atmosphere.

Methane (CH4) is produced when organic materials of any kind decay in a place where there is little or no oxygen (landfills contain very little oxygen). Methane can also be burned as a fuel, which is why anaerobic digestion (AD) facilities make sense in many circumstances. AD facilities take organic wastes like manure and food scraps and turn them into methane, which is then burned to produce energy. Burning the methane converts it back to CO2 and reduces the amount of fossil fuels we need to burn for our energy requrements. AD facilities also produce a "digestate" that can be used as a fertilizer on farm land (although here at the Compost Council we prefer that the digestate be composted prior to being applied to land, as this reduces both residual methane emissions and nutrient run-off from the fields).

Recycling in all its forms can reduce the amount of GHGs that we add to the atmosphere. The same goes for burning wood, or any other form of biomass, instead of fossil fuels. All of these things are essentially ways to make our products or make our energy with less GHG released to the atmosphere. However, the addition of compost to soil can actually pull existing carbon out of the atmosphere, reducing current GHG levels. How does it do this? The addition of compost increases the beneficial life in the soil -- microbes like bacteria and fungi. These microbes both help plants grow and also help trap the resulting carbon in the soil, where it increases the soil's fertility. So, plants use CO2 to make biological carbon, through photosynthesis, then when they die, that biological carbon gets turned into what we call soil humus -- the nice-smelling dark brown component of healthy soil. When you add compost to soil, you not only make the soil healthier and help your plants grow better, you also "sequester" carbon in the soil, helping to fight climate change.

In general, tipping fees for most recyclables is less than the tipping fees for waste. The secret to saving money is in having an efficient system for separating these materials at source, because contamination increases tipping fees and costs to the company. Organics are also often less expensive to tip than waste, but the collection of organics can be expensive. However, some of the new collection options are no more expensive for organics than for any other material. Where the real savings can be realized, however, is with the frequency of collection of waste. When organics are removed from the waste stream, waste containers can be stored longer on site, without fear of odours or pests. This allows for less frequent pick-up, which can generate substantial savings.

Carbon dioxide is the most common GHG. Even though, at 0.04%, it is a small percentage of the atmosphere, it traps the sun's heat, causing an overall rise in temperature, just like the windows of your car on a sunny day. Methane does the same thing, only about 28 times better. It's a good thing that methane is at even lower levels (about 0.0002%) in the atmosphere than CO2 (although our landfills are doing their best to change this -- more on that later). Neither oxygen (21% of atmosphere) nor nitrogen (78%) are GHGs.

The mining and processing of aluminum takes huge amounts of energy, most if not all of which comes from burning fossil fuels. Recycling saves 95 per cent of that energy, and thus up to 95 per cent of the CO2 that would have been released.

Composting programs accept food scraps and most also accept contaminated paper products, such as soiled food wrapping or cardboard with food stuck to it (e.g., pizza boxes). They also accept paper napkins, tissues, and soiled newspaper. Most recycling programs accept clean corrugated cardboard, but not boxboard (single-layer carboard, like cereal boxes), so put the boxboard in the organics bin unless otherwise informed by the collection company. Never put plastic of any kind in an organics collection container.

As you can see, aluminum is very energy-intensive to produce, so the savings are significant. With glass, at the other end of the spectrum, the only saving is that the furnace can run at a lower temperature when recycled glass is the main input, rather than raw materials.