Landfills are not just a resting place for waste; they're active bio-chemical reactors that significantly contribute to global greenhouse gas emissions, especially methane. When we underestimate these emissions, we risk formulating policies that fall short of addressing a key driver of climate change.
How Methane is Produced in Anaerobic Conditions
The generation of methane in landfills occurs under anaerobic conditions when organic waste decomposes without the presence of oxygen. Microbial activity in waste layers produces methane as a byproduct, which, if not managed properly, escapes into the atmosphere, exacerbating the greenhouse effect.
The Scholl-Canyon Model for Methane Generation
For years, the Scholl-Canyon model has been the gold standard for predicting methane emissions from landfills. It has shaped policy decisions by providing a framework to estimate methane production over the lifespan of a landfill. This model accounts for the rate of waste decomposition and the methane generation potential, forming the backbone of many environmental impact assessments. Image depicts a time in the future where people visit landfill museums to learn about the time when resources were squandered in landfills where the resources decomposed to methane pollution a major contributor to climate change.
Shortcomings of the Scholl-Canyon Model
Despite its widespread use, the Scholl-Canyon model has its limitations. It spreads methane emissions linearly over 40 years. However, evidence suggests that as much as 40% of methane emissions occur within the first five years post-deposition. This time discrepancy leads to an underestimation of the immediate impact of landfills on climate change, pointing to the urgent need for revised models that consider the early peaks in methane release.
The Real Global Warming Potential of Methane
While traditionally scientists have used a global warming potential (GWP) of methane being 28 times that of carbon dioxide over a hundred years, recent evidence indicates that methane is 87 times more potent over a 20-year period. This new understanding calls for an urgent reevaluation of climate change models to reflect methane's more immediate and intense impact on global warming.
The Need for Updated Modelling
Updating the Scholl-Canyon model to reflect the true short-term impact of methane would reveal a more daunting picture of its contribution to global warming. By recognizing the disproportionate effect methane has in the initial years, we can steer policy towards more aggressive landfill avoidance strategies.
Real World Example: Hotel Blackfoot's Landfill Initiative
In a notable real-world application of sustainable practices, Hotel Blackfoot in Calgary, Alberta, has collaborated with Emissions Reduction Alberta (ERA) to tackle its waste management. The project has highlighted a significant landfill waste stream from the hotel, amounting to 262 metric tonnes annually. Utilizing the Scholl-Canyon model to estimate the potential greenhouse gas (GHG) emissions from this volume of waste, the findings are 502 metric tonnes per year for 40 years equaling 502 x 40 =20,080 metric tonnes of CO2e GHG emissions over 40 years.
Accounting for the non-linear rate of decay and using the 87x GWP of methane over 20 years, the landfill GHG emissions from this single 262 metric tonnes in landfill will generate an incredible 24,899 metric tonnes of CO2e pollution over the first 5-years. This calculation represents an astonishing emission factor of 95 times the original waste amount. Such a high emission factor underscores the critical need for immediate effective waste management strategies and the importance of adopting landfill avoidance technologies.
In conclusion, while the Scholl-Canyon model has served us well, it's time for an update. It's crucial that our policies reflect the latest scientific understanding of methane's impact, to catalyze immediate action for climate mitigation. Only then can we hope to craft policies that truly address the scale of the challenge posed by landfill methane emissions.
This blog serves as a clarion call for policymakers, scientists, and environmental advocates to acknowledge the urgency of updating our emission models. The stakes are high, and the time to act is now.
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