Cars, trucks, and factories with smokestacks belching clouds of noxious gas – these are perhaps the most obvious culprits of climate change.
But consider banana peels, wilted lettuce and stale bread: as these organics break down they produce methane gas, “and methane is one of the worst greenhouse gasses,” Craig Scott, executive director of Ecology North, said Tuesday.
“Landfills around the world are releasing all this methane and it's mostly because of the organic material.”
A 2014 study of methane in the journal Nature states the gas has about 25 times the global warming potential of carbon dioxide, which is produced from burning of fossil fuels.
The city of Yellowknife estimates that organics account for about 30 to 40 per cent of household garbage.
In 2008, Ecology North started a five-year pilot project with the city to collect kitchen scraps and keep organics out of the solid waste heap.
By the project's end in 2013, says the city, 900 tonnes of organic material were diverted away from the landfill, which in turn reduced the city's greenhouse gas emissions by an estimated 870 tonnes. The project also produced more than 450 tonnes of garden-ready compost.
This project laid the groundwork for curbside compost collection in Yellowknife, which was made available to all single-family homes last October.
Ecology North continues to run Yellowknife's composting program, turning today's apple cores, egg shells and coffee grounds into tomorrow's marketable gardening material.
But mitigating methane gas emissions is just one piece of the solid waste management puzzle.
Expanding the landfill is costly, and the city is grappling with how to slow down the pace at which the dump fills up.
“Everything we add in there gets us closer to triggering this big payout to close and open a new landfill site,” said Scott.
The city hopes to eventually divert 40 per cent of waste away from the landfill and last year hired Sonnerva Inc. to do a waste audit and develop a waste management plan. The results of that audit and the city's response have yet to be released.
“Our landfill is actually full,” said Scott, but there's a quarry right next door that has been taking the overflow for a number of years.
“Now it's a question of whether we're filling up the landfill faster than the quarry is taking out the rock, and whether that quarry is going to continue to be operational,” he said.
City spokesperson Iman Kassam said the new landfill in the quarry has an area of about 2.9 hectares (larger than seven football fields).
The old landfill was 23 hectares – about eight times the size.
Kassam said the city is building landfill cells – areas designed to contain solid waste – that will last between five and 10 years. As one cell fills up, a new one will be built.
The city moved most of its solid waste operations in 2017 to a new cell that cost $3.7 million to build.
Another new cell is in the works for 2022, which will cost an estimated $4 million.
Kassam said the landfill will continue to grow “as space becomes available and the need arises.”
One item that takes up a lot of space and doesn't actually belong in the dump, said Scott, is cardboard.
He said cardboard, (which, it should go without saying, is recyclable,) accounts for about 30 to 35 per cent of the landfill's contents in terms of volume.
“There is no reason why anyone should be putting cardboard into a waste bin,” said Scott.
Recycling or reusing the stuff, he said, “is something that everyone can do to help the city save money and reduce our environmental footprint.”
According to the Corporate and Community Energy Action Plan: 2015-2025, the city is aiming to divert 80 per cent of organics and 100 per cent of cardboard away from the landfill by 2025.
In doing so, Yellowknife could cut GHG emissions by 9,185 tonnes, which is about 17 per cent of its overall emissions reduction target.
The city's forthcoming waste management plan could include new diversion and GHG reduction targets.
It's unclear when the landfill will stop taking trash for good, or how much it will cost to reclaim the site.
The city is currently working on a closure plan with the Mackenzie Valley Land and Water Board.