By Dr. Neil Tangri, Science and Policy Director, GAIA
Good news is hard to come by on the climate change front these days, but the massive new Global Methane Assessment has some, if you squint just right. As greenhouse gases go, methane doesn’t get as much attention as carbon dioxide or even refrigerants, but it’s extremely important — especially if we want to put the brakes on global heating in the next few decades. The reason is that, ton for ton, methane traps far more heat than carbon dioxide; but it also has a short lifespan. The carbon dioxide that we release into the atmosphere will be there for hundreds of years, but the methane will break down in a few decades. That means that, with concerted efforts, we could actually bring atmospheric methane concentrations down, centuries before carbon dioxide starts to dip. And that will be an important first step toward cooling off our overheating planet.
Bringing methane concentrations down is still a heavy lift, though — not only are concentrations rising but emissions continue to rise as well. The methane assessment spotlights the oil and gas industry as the primary culprit — methane leaks from wells, pipelines, and other infrastructure are the largest source of anthropogenic methane, and a strong argument (as if we needed more) to phase out natural gas as quickly as possible.
To bring down methane concentrations, we’ll have to go beyond the oil and gas companies and tackle all major sources. The second largest source of anthropogenic methane emissions is landfills. This is a different beast entirely — landfill methane is produced when food waste and other organic waste rots inside a sealed environment. Anaerobic microbes break down the organic matter and release methane, which finds its way to the atmosphere. Tackling landfill methane offers the promise of multiple wins — after all, food waste shouldn’t be thrown away in a landfill to begin with, and addressing that bad practice can unlock all sorts of solutions.
There is a waste management strategy that tackles methane emissions in a holistic way, while also minimizing other environmental impacts and maximizing social benefits, such as the integration of informal waste workers. This strategy is called zero waste — a comprehensive, practical and inexpensive approach to waste management. Zero waste tackles methane emissions through the following steps, in order of priority:
- Reduce food loss and waste. Reducing supply chain losses and consumer wastage means fewer emissions in food production and less food thrown away.
- Implement source separation. Collecting organic waste separately from garbage and recyclables is critical. It keeps food from emitting methane in landfills, and instead puts it to good use as compost. It also improves the recycling rate by preventing contamination.
- Use the organics. Organic discards are full of carbon and valuable nutrients. Composting (at home or in a municipal facility) returns these to the soil, improves soil fertility, improves water retention (reducing vulnerability to drought and floods), and reduces the use of synthetic fertilizers.
- Alternative uses for organics include animal feed and biogas (produced through anaerobic digestion). Both approaches have been widely successful.
- Stabilize the residual. Using Mechanical-Biological Recovery and Treatment (MBRT) to process the residual before landfilling reduces methane generation by 80-90%.
- Install methane capture at landfills. Old landfills will continue to produce methane for decades; landfill gas capture systems are effective at capturing this methane and can generate heat or power on site.
- Apply biologically active cover to landfills. Selected soil organisms break down up to 80% of fugitive methane emissions.
The genius of zero waste is that it turns a problem into a resource. Whether composted, fed to animals, or turned into biogas through anaerobic digestion, organic discards are too valuable to be sent to landfill. Capitalizing on this resource is inexpensive and generates new jobs and economic activity.
When tackling landfill methane, there is one important trap to avoid — the burner trap. The incinerator industry is eager to position itself as a solution to climate change. The facts, however, say otherwise. For one thing, incinerators are themselves major emitters of greenhouse gases (as well as a witches’ brew of other toxic and ecotoxic pollution). And since food waste is too wet to burn on its own, incinerators must also burn large quantities of fossil fuel — either plastic or coal — to burn the food waste. Incineration competes directly with recycling for burnable materials such as plastic, wood, cardboard, and paper. And, because incinerators must constantly be fed with waste, incineration discourages waste reduction. Of course, waste reduction and recycling are the two most effective ways to reduce emissions from waste. Incineration is by far the most expensive approach to zero waste management — any city contemplating an incinerator could save itself money and emissions by going zero waste instead.
For more, see our new factsheet on zero waste and landfill methane.