Where does your mind go when you think about the causes of climate change? I usually picture the tree stumps left behind by deforestation, the shimmer of oil floating on seawater, or the gray clouds billowing from a factory smokestack–big, dramatic events created by immense, faceless entities that feel impossible to change.

What I didn’t always consider, however, was that a significant cause of climate change might be wilting in a forgotten corner of my refrigerator or growing overripe on my countertop. I’m talking about one of the top human-generated causes of climate change: food waste.

What is Food Waste?

The exact definition of food waste varies across governmental agencies and organizations. According to the Food and Agriculture Organization of the United Nations (FAO), food loss occurs due to issues along the supply chain, such as crops not being harvested or food spoiling during processing and transportation.

Food waste, on the other hand, occurs from a conscious decision to discard food that could have otherwise been consumed or recycled. The U.S. Environmental Protection Agency highlights that “food waste occurs at the retail, food service, and residential levels and is managed by landfill; controlled combustion; sewer; litter, discards and refuse; co/anaerobic digestion; compost/aerobic digestion; and land application.”

Estimates from the U.S. Department of Agriculture and Feeding America place the level of food loss and waste in the United States somewhere between 119 and 133 billion pounds of food, approximately 30-40% of our national food supply. The nonprofit organization ReFED estimates that residential food waste made up 48.4% of all food waste in the United States in 2021, with 68.9% being disposed of through landfills, sewers, or incineration.

What is the Environmental Impact of Food Waste?

Before food reaches our tables, there is already a significant ecological cost behind the manufacturing and transportation of food across the country. The EPA compared the level of greenhouse gases, such as carbon dioxide, emitted from our current food systems as being comparable to the emissions from “more than 42 coal-fired power plants.”

Most households are guaranteed access to garbage disposal services directed towards landfills, whereas access to recycling and composting services can be limited based on municipal resources and the ability for individuals to opt in. When cities direct food waste toward landfills, the decomposition process releases methane into the atmosphere, a major contributor to global warming.

When cities direct food waste toward landfills, the decomposition process releases methane into the atmosphere, a major contributor to global warming.

The EPA notes that municipal solid waste landfills make up approximately 14.3% of human-generated methane emissions, “approximately equivalent to the greenhouse gas (GHG) emissions from nearly 23.1 million gasoline-powered passenger vehicles driven for one year.”How big of an impact does this make on the environment? Globally, food waste contributes nearly 10% of greenhouse gas emissions. “If food wastage were a country,” writes the United Nations FAO, “it would be the third largest emitting country in the world.”

How Can We Decrease Our Impact?

Shopping With Intention

The Wisconsin Department of Natural Resources offers tips such as taking inventory of the food you already have at home, shopping with a grocery list, and auditing your grocery purchases over time to check if any food is regularly going to waste. 

When shopping and taking stock of what you already have, it’s important to note that most “expiration date” labels on packaged food are often indicative of food quality rather than food safety. According to the Harvard School of Public Health, the “use by” label is only federally regulated when used to indicate the safety of baby formula and foods. Otherwise, most dates on packages are simply recommendations from manufacturers of their products’ optimal freshness. The USDA notes that true spoilage can be determined when food undergoes “a change in color, a change in texture, an unpleasant odor, or an undesirable taste.”

Most dates on packages are simply recommendations from manufacturers of their products’ optimal freshness.

Finally, shopping from farmers’ markets and grocery co-operatives that source their products locally and regionally can reduce the volume of greenhouse gases emitted from the production and transportation of food, and ensure that we’re receiving the freshest produce possible.

Cooking Creatively

Wilted herbs, wrinkly vegetables, and slightly mushy fruits may look unappealing at first glance but still have quite a bit to offer! Cookbook writers such as Dana Gunders (Waste Free Kitchen Handbook), Tamar Adler (The Everlasting Meal Cookbook), and siblings Margaret and Irene Li (Perfectly Good Food) encourage home cooks to adopt more sustainable food storage habits and explore more flexible cooking strategies that can be adapted to any ingredients that are on hand. For example, ideas from Perfectly Good Food include “cream-of-anything soup,” “toss-in-any-vegetable stew,” and “an endlessly riffable fruit crisp.”


Composting is a natural process that turns your everyday kitchen food scraps and plant matter into a nutrient-rich soil-like material, which can then be repurposed in your garden. Composting offers the benefits of diverting food waste from landfills and improving the quality of the soil around you for future plants to thrive. For a primer on how to start composting, check out the Hummingbird composting guide.

Advocating for Change

Though there is a lot that can be done to prevent food waste at the individual level, it’s apparent that we need to build a post-consumer pipeline to divert food from landfills at a greater scale. The Milwaukee Climate and Equity Plan proposes the creation of a partnership between public government entities, nonprofit organizations, and private parties such as grocery stores and restaurants to ensure that excess food is diverted to communities experiencing food insecurity. The initiative also calls for improved municipal waste collection, including a more robust and easy-to-understand recycling program and increased access to organic waste collection.

Organizations such as the Our Future Milwaukee Coalition are on the frontlines of advocating for the adoption and implementation of the Milwaukee Climate and Equity Plan. You can sign up to receive more updates and learn how to get involved here.

Every Bit Counts

Many of the issues contributing to food loss and waste happen out of our direct control, long before an apple or a carrot even has the chance to cross our path. But there is still so much that we can do in our day-to-day lives to break the cycle of waste and reduce our climate footprint. What new action will you take to decrease food waste?