Food Waste is a Major Contributor to Climate Change. What Are the Solutions?

What drew you to study food waste?

Reducing food waste is pretty much the most actionable measure humanity can take to mitigate greenhouse gas emissions in the short and medium term. It’s easy to find policymakers, consumers, and business leaders with strong opinions on how to mitigate food-waste emissions, but when I started my career, there was amazingly little empirical, scientific research on the topic.

For example, policymakers and scholars have a hypothesis that 7–10% of all food waste stems from confusion about the meaning of expiration-date-label formats (e.g., “best by” vs. “use by”). California even passed a law (AB 660) on the basis of these claims about these date labels, hoping to motivate people to not dispose of food that’s safe to eat, but there’s still no scientific evidence of how these date-label formats actually affect purchases and waste in the field—that is, when real choices are made.

Broadly speaking, I am motivated to find out what policies actually work to reduce greenhouse gas emissions from food waste. That’s where I think the scientific approach is important, because, as a researcher, I don’t have any stake in my findings going one way or the other. If a policy doesn’t work, but society thinks it does, that’s just as important as confirming that the policy does indeed work. And as a scientist, it’s also my job to investigate why a policy is or is not working. I want to find the truth of how we can address this problem that is a major contributor to the climate crisis.

What are some of the most effective ways to reduce food waste?

In 2023, the total emissions from food waste was 5.4 billion metric tons, and food waste also costs the grocery retail industry about $27 billion every year. So what can we do about this problem? My research in this space focuses on two potential solutions: food-waste landfill bans and dynamic pricing.

So let’s take these solutions one at a time. First, food-waste landfill bans are a way for the government to directly regulate food waste by imposing a penalty on retailers who try to send their food waste to landfills. The problem is food waste bans don’t work all that well for a couple of reasons. So first, these penalties aren’t typically large enough to get retailers to really change their behavior. Also, it turns out governments aren’t all that great at enforcing these bans. My coauthors and I investigated the efficacy of the first five food-waste bans in the United States, and we found that only one state, Massachusetts, has been successful at diverting food waste away from landfills. The data suggest that the success is likely because the state enforces its ban, the ban is the easiest to understand of the five, and the state has a superior composting network.

The other solution I investigate is dynamic pricing. More than 10% of food waste comes from grocery retailers that throw out surplus perishables past their expiration date. Dynamic pricing spurs retailers to throw out less food by applying an algorithm that determines when grocery stores should reduce the price of perishables depending on their inventory and expiration date. This way, vendors can change the price of food multiple times a day, compared to static pricing in which products have the same price all day. It also makes perishables, which are less processed and generally healthier, more affordable. In most cases, it saves grocers money, consumers money and creates less food waste. To an economist, it’s actually really weird that grocery stores don’t dynamically price their perishables. Why should you, the consumer, be paying the same price for milk that will expire one week from now as you would for milk expiring three weeks from now?  Not only is it unfair, it’s inefficient.