Circular File: Leaving Only Footprints

We Americans don’t make garbage like we used to. But we still make a lot; probably more than 250 million tons in 2011 and twice as much if construction and demolition debris and non-hazardous industrial waste are included. Private and public sector operations collect this material and then process it for recycling, put it in compost piles or send it to landfills or waste-to-energy facilities for disposal. In doing so, we provide an essential public health and environmental service.

Yet, even as we do well, our greenhouse gas emissions leave a carbon footprint on the environment. The good news is that we emit only a very small part of America’s greenhouse gases. According to EPA’s draft estimates for 2011, our country emitted 6708.3 teragrams of carbon dioxide equivalent (TgCO2E). Of this, 121.5, or 1.81 percent, were produced by the solid waste and recycling industry.

Methane is our primary contribution to greenhouse gas emissions, with 104.5 TgCO2E in 2011. Landfills produce virtually all of this methane. Compost facilities produce a very small, but increasing, amount. Again, the good news is that landfill emissions have been reduced by a whopping 30 percent since 1990. We accomplished this by continued advances in our ability to convert landfill gas into energy. We also capture and destroy methane through flaring and oxidation. Perhaps the best way to note our progress in reducing methane emissions is that landfills were the second largest methane producer when EPA began tracking greenhouse gases in 1990. Now they are the third. Natural gas systems and “enteric fermentation” (the digestive process used by ruminant animals such as cows), each produce more methane than landfills.

By far, carbon dioxide is the most emitted greenhouse gas in our country. Burning fossil fuels creates most of these emissions. Our industry produces less than one half of one percent of America’s carbon dioxide emissions. Most is produced by waste-to-energy facilities. Yet, the energy produced by these facilities and by landfill gas recovery efforts means that less elec- tricity needs to be produced by coal or oil-fired plants. Collection trucks and energy used at processing facilities also produce a small amount of carbon dioxide. Finally, both composting and waste-to-energy facilities produce a small amount of nitrous oxide.

Our industry has a good track record in reducing emissions and creating environmental benefits. Without energy recovery, flaring and oxidation, methane emissions would have been well over twice as high. The Nobel- Prize winning Intergovernmental Panel on Climate Change (IPCC) cites landfill gas recovery for its ability to reduce greenhouse gas emissions. And both the EPA and the IPCC credit landfills with “sequestering” (storing) carbon due to incomplete degradation of organic materials such as wood products and yard waste. The IPCC estimates that half of the “organic” fraction in a landfill does not degrade because lignin is “recalcitrant” and the cellulosic portion degrades slowly. This is a sequestration that anyone can support!

Recycling offers another climate change success story. By avoiding the far greater amount of energy needed to transform virgin materials into new, recycling has reduced America’s total greenhouse gas emissions. Recycling paper also increases carbon storage
in trees by easing the pressure to cut down our forests.

Climate change is not the political issue it once was. But sooner or later, Congress will return its attention to climate change. When the issue heats up again, our industry has a good story to tell.