Compost is King When it Comes to Climate Change

Food waste is one of the top bananas in global emissions.

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By: Dana Hoffman

What images come to mind when you think about climate change and its impacts? Belching smokestacks, perhaps? Polluting car tailpipes, maybe? Flooded out seaside towns?

Or rather, that banana that was on your counter for several weeks before you got around to eating it, turned brown and limp, and ended up in the trash. (We’ve all done it one time or another!)

That banana in the trash is as big a part of climate change as that coal plant. The World Wildlife Foundation estimates that in the US alone, the production of lost or wasted food generates the equivalent of 37 million cars’ worth of greenhouse gas emissions. And the World Resource Institute has this devastating figure: if food waste were a country, it would be the third-largest emitter of greenhouse gases behind China and the U.S. So while a staggering 1/3 of food goes to waste globally, the problem is even bigger here in the US, with the best estimates indicating that 40% of food produced for US consumption goes to waste.

Organic waste, and specifically food waste, is therefore one of the areas where the greatest impact can be had in cutting back our climate emissions. In fact, Project Drawdown, a coalition of experts focused on climate change solutions, ranks reducing food waste as the №3 action item out of 80 — to the tune of more than 70 gigatons of carbon reduction.

Core Matter wants to focus on solving the largest-scale climate changes issues affected by human systems and behavior, and municipal composting fits that bill. After Project Drawdown helped us hone in on food waste, we consulted the research of ReFED, a coalition focused on food waste. They’ve identified 27 solutions specifically focused on food waste. When looking at emissions reduced, centralized composting was at the top of that list. Since we believe local problem-solving often leads to the best global solutions, we’ll be focusing our research, ideation, and prototyping in our hometown of Oakland, CA in the East Bay. And while we have respect for the worm whisperers in their backyards, we wanted solutions that can be easily scaled, so we focused on municipal composting.


We have spent the last several months learning about Oakland’s municipal composting through reviewing municipal waste contracts, city ordinances, studies, and interviews. The solid waste system is complex on many levels, including (but not really limited to) transportation logistics, public behavior influencing, and facilitating safe chemical breakdown of compost materials.

Here are just a few components of the big picture:

  1. Ambitious Zero Waste Goals

In 2006, the City of Oakland set a Zero Waste Goal, which called for cutting the amount headed to landfill each year to 40,000 tons per year (near zero) by 2020. This was highly ambitious for the time. Likely overly ambitious. Over the last several decades Oakland and its Alameda County neighbors have made big strides, successfully achieving the 50% waste reduction goal mandated by state law (AB 939). The City of Oakland tracks all waste that goes through the municipal collection system and shared the last four years of that data with our team via public information request. That data tells us that while there continue to be dedicated resources and policy to waste reduction by the City, Alameda County, and the State of California, progress toward reaching zero waste going to landfill has largely come to a standstill. Oakland has sent roughly the same amount to landfill each year for the last four years, as shown in the bar chart below. Oakland will not reach its goal of reaching zero waste by 2020.

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Source: Waste Management Annual Tonnage, procured through public information request

2. A League of their Own — Oakland’s Compost System has Several Big Players

The Environmental Services Division is the small but mighty section of the City of Oakland’s own Public Works Department that runs its Recycling and Solid Waste Program. Understanding the solid waste picture for Oakland though, requires getting to know several other big players. Waste Management Inc. (WM), the exclusive provider of compost and trash collection services for Oakland, is one of the biggest waste disposal companies in the world. After much controversy, in 2015, WM secured a 15-year contract with the City, and in doing so committed to a series of goals to divert waste from landfill. Also on the field is StopWaste, a unique independent government agency that oversees waste management goals for all of Alameda County and its city members. StopWaste is the author of the County’s and member jurisdictions’ Integrated Waste Management Plan, which serves as the state-mandated roadmap documenting how the county will go about achieving local solid waste management and recycling mandates from the state and local goals as well.

3. Carrot or Stick? How about both?

In Oakland, unlike much of the rest of the country¹, composting is required, not only for single-family homes, but for apartment dwellers and businesses as well. In fact, you can even be fined if you throw out too much that could be composted.² Oakland also provides financial incentives, as paying for landfill bins or tonnage (depending on the type of customer) costs more than composting, according to the City’s designed rate structure. These two policies — on the one hand a cost, and the other hand, an incentive — can operate powerfully together. But the question remains whether they go far enough. Should the incentive be greater? Should the fines be higher? If the fines are higher, will it hurt small businesses or vulnerable populations?

4. For Composting Follow the Yellow Brick Road? Try the 580.

Composting in Oakland takes a three-part journey in its cycle of use. The map below from StopWaste shows this journey, a screenshot of a dynamic online map that shows the waste materials flow for every jurisdiction in Alameda. First, food waste and other organic matter placed in the green bins by Oakland residences and businesses are collected by the contracted waste hauler, Waste Management, and taken to the Davis Streets Transfer Station in San Leandro. Second, the compost is hauled roughly 40 miles to the Altamont Compost Facility in Livermore, which processes up to 500 tons per day of residential green waste co-collected with food waste from around the region. After being processed into composting, it’s bagged up and sold to farmers, gardeners, and landscapers under the brand WM EarthCare™.

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Source: Alameda County Materials Flow Map from Stop Waste,

Key Takeaways from our Research

A first takeaway from the municipal waste data collected by the City of Oakland is that the recent trend shows landfill rates and compost rates have been stagnant. Oaklanders are not composting more than they were four years ago, despite ongoing efforts. Why are Oaklanders still throwing out their old bananas instead of composting? Composting is a difficult issue to tackle with lots of obstacles. Objectively speaking, Oakland and Alameda County’s StopWaste have together already implemented just about all the practices and policies that are considered best practices nationally.

Which leads us nicely to the next takeaway, which is that Oakland may need to revisit its waste goals. In 2012, Oakland’s then city council set an aspiring and bold goal when they passed the Zero Waste ordinance. Boldness and aspiration are great, and indeed necessary given the scope of the climate crisis we face, but need to be paired with realism. Oakland has not and cannot reach 100% diversion of waste by 2020. Oakland’s mechanisms to keep making progress on improving composting rates are actually tied up in solid waste contracts and sector fee charts. These are hardly aspiring or inspiring. In fact, even if the average person were to track down this document, it’d be a feat of commitment to read it all the way through.

One simple, powerful tool to implement could be tracking progress and sharing it, in an easy-to-read, hopefully graphically appealing way, with the world. Having an accountability buddy helps with making progress. As any public agency staff may think from time to time, that public documents create too many accountability buddies, in the end, tracking info and sharing trends in a clear and cohesive way with the community is a powerful tool for progress (political will, problem identification). This kind of tracking will highlight what the biggest barriers are and then hopefully lead to ways around them. Tracking can also help inform more realistic goals for the future.

In fact, pulling the data into a bar chart helped us identify a big weak link for Oakland’s composting progress: multi-family (MF) residents produce, by far, the least tonnage of composting.

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Source: Source: Waste Management Annual Tonnage, procured through public information request. Multi-family properties (5+ units) are required to have recycling and composting collection service for their residents. Effective January 1, 2017 the compost/organics provision of the Alameda County Mandatory Recycling Ordinance (MRO) is being enforced by the Alameda County Waste Management Authority. Multi-family properties are also subject to mandatory organics by the State of California under AB 1826.

We can expect somewhat lower tons of compost compared to single family, since, by and large, MF residents don’t have yards and therefore don’t produce all yard waste, but that wouldn’t account for how low these numbers are. Especially given that Alameda county took the bold step of requiring composting in multi-family in 2017, we might have expected to see some kind of jump in tonnage since then. But we don’t. So, what’s going on? Well, turns out MF is especially tricky from a composting perspective for lots of jurisdictions. But that doesn’t mean it isn’t worth tackling, especially when you consider that the majority of Oaklanders live in multi-family housing.

So we’ll be exploring apartment dwellers’ experience with composting as well as continuing research towards human-centered solutions. We’ll share what we find with you in our next blog.


[1] Organic and food waste requirements are becoming more common. In fact, at least five states, including California, Vermont, Connecticut, Massachusets, and Rhode Island mandate composting for at least some sectors. However, this is still relatively uncommon. In fact, according to a report by Biocycle in 2014, only 198 communities in the US provide curbside collection of composting, although many others to have some form of centralized composting occurring.

[2] Alameda County has several ordinances, including the Mandatory Recycling Ordinance 2012–01 and the Plant Debris Landfill Ban Ordinance 2008–01, which collectively require both composting and recycling by all users, whether they be homes or businesses. Profligate transgressors risk fines. Oaklanders also pay more for landfill bound waste compared to recycled or composted.

[3] Reviews of trends should generally extend more than 4 years since a single year outlier can drastically skew data. However, with science telling us we have just 9 years left to tackle climate change, we must evaluate whether we have turned the corner over short time scales.

Aligning climate solutions with human systems.

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