Less than a month ago, a UN report came out saying we need to reduce our emissions by 7.6% per year on average beginning in 2020 to meet the 1.5 degrees Celsius warming limit. 

Meanwhile, our greenhouse gas emissions have RISEN by 1.5% over the past decade.

Just this past week, the 25th United Nations Climate Change conference concluded by postponing major decisions on carbon markets because of opposition from countries like the United States.  More locally, NorthWestern Energy is proposing to build four new fracked gas plants and no new renewable energy.

The state of the climate certainly is bleak.  It’s time we move beyond just commitments to reduce our contribution to climate change and start acting, and mandatory composting is one of the low-hanging fruits we can turn to.

About 30% of our municipal solid waste comes from organic material like food waste and yard trimmings.  Nationwide, over 40.6 million tons of food waste went to the landfill in 2017, nearly all of which could have been composted. 

That organic material creates methane when it breaks down anaerobically at a landfill, and methane is a potent greenhouse gas.  Methane has a global warming potential that is 72 to 105 times greater than carbon dioxide (CO2) over a 20-year period. 

According to the EPA, landfills are the third-largest human-made source of methane emissions in the country and account for about 14% of American methane emissions.  Locally, Missoula’s landfill accounts for about 9% of our community’s emissions, and emitted 26,644 metric tons of CO2 equivalent in 2018.  

Normally, methane is collected and flared to control odor, mitigate human and environmental health risks, and to more or less safely dispose of flammable constituents and prevent landfills from exploding.  However, a significant amount of methane escapes as fugitive emissions.  

Some landfills utilize landfill gas to energy technology to convert the methane from landfills into energy.  However, there will always be fugitive methane emissions, whether flaring methane or converting it to energy, and there’s conflicting data out there about how much methane is actually captured. 

The EPA says the Missoula landfill has a collection efficiency of about 75%, although based on the inputs and modeling that could be as low as 20% to 35% or 54%.  It’s difficult to accurately calculate how much methane is collected from landfills.

But one way to know for sure that your food and yard waste isn’t producing methane is to compost it.  Because composting is an aerobic process, it doesn’t produce methane. Composting not only avoids methane emissions but actually reduces emissions, even when taking into account transportation emissions (of course even more emissions can be reduced if you compost in your backyard). 

Over the course of a nine-year study, the Rodale Institute has found that applying compost to cropland can sequester as much as 10,802 pounds more carbon dioxide per hectare each year than farming with conventional manure fertilizer and can also reduce nitrate leaching by 600%.

Composting also has the added benefit of slowing the rate at which our landfill fills up.  The estimated closure date for the Missoula landfill is 2069, and if we’re not zero waste by then, we’re going to need another landfill — that's less land for the environment, less land for recreation, less land for all of us.  So, let’s make significant progress toward our zero waste goals and toward reducing our greenhouse gas emissions and start composting.

Eliot Thompson is a volunteer with the Montana Chapter of the Sierra Club.

This Sustainable Missoula column is brought to you – via the Missoula Current – every Friday by Climate Smart Missoula and Home ReSource.

Upcoming Sustainability Events

Now through January. Dear Tomorrow Missoula letter writing project, sponsored by Climate Smart Missoula and Families for a Livable Climate. Dear Tomorrow is a global storytelling project focused on sharing personal messages about climate change to inspire action. Details here.

Sunday, January 12. Fixit Clinic. Coaching & tools for sewing/mending, 3-D printing, soldering & more. Registration encouraged here. Home Resource Community Room, 1515 Wyoming St. 11 a.m. – 3 p.m. Free event. More info here.

January 13. City Club Missoula forum: Making Missoula County Climate Ready. Climate Smart Missoula, Missoula County, and City of Missoula will release Missoula’s climate resiliency plan and discuss insights. 11:30am, DoubleTree Hotel conference room. 

January 13. Climate Change and how it affects our native plants and animals. Free talk by Kelsey Jencso, MT state climatologist & lead author of Montana’s Climate Assessment. 7 pm, UM’s Gallagher Business Building room 123.

January 16. UM’s Seeking Sustainability Lecture Series kicks off. Meets Thursdays from 7 to 8:30 pm Jan 16 through May 7 in Gallagher Business Building room 122. Open to the public. Learn how UM and Missoula city/county government, nonprofits and businesses are working together to create a more sustainable society and how you can help. For schedule and/or syllabus, email vicki.watson@umontana.edu.

February 19. The Big Climate Change Event. Join us at the Wilma. 7pm. Save the date and stay tuned.