Picture this: You live in Signal Hill, California, an 11,000-person suburb just south of Los Angeles. You moved there because the homes are more affordable than elsewhere in the region, buying a single-family home in a neighborhood of single-family homes. As a result, you have to travel to the grocery store, the doctor, and your kids’ school, so you bought a used 2015 Chevrolet Suburban, which gets about 18 miles per gallon—not too bad when gas was cheap. You drive 30 miles each way to your office in Santa Monica because the trip by bus and train takes far longer.
For your life and your resources, these purchases are necessities, but you can’t help but wonder whether your lifestyle—your house and your driving—has something to do with climate change. You know climate change is ravaging your area because your county recently experienced a five-year drought. And local and national news outlets treat rain in Los Angeles as a news-worthy event.
It’s a fair question: What, exactly, is the relationship between land use and greenhouse-gas emissions? What can policymakers do to maintain your quality of life and address climate change? And what can you do, if anything at all?
How does land use influence greenhouse-gas emissions?
Thanks to the rise of renewable energy sources and more-efficient end users (like household appliances), the electricity sector’s greenhouse gas emissions—the pollutants that contribute to climate change and warming planet—declined by 33 percent across the United States between 2005 and 2019.
That’s a positive trend that could help meet the nation’s goal of a 50 percent reduction in greenhouse gas pollution from 2005 levels by 2030.
Unfortunately, in the sectors most closely related to land use, the story isn’t nearly as positive. Between 2005 and 2019, transportation-related emissions decreased by just 5 percent, and the direct emissions from commercial and residential buildings increased by 8 percent. In 1990, 36 percent of the nation’s emissions were derived from those sources. In 2019, 41 percent of emissions were.
The increasing relative contributions of the transportation and buildings sectors to greenhouse gas emissions raise questions about how we plan our cities.
Although surveys suggest most people think densely populated areas emit more, neighborhoods and cities that are more densely populated actually produce fewer per capita carbon emissions than sprawling, spread-out communities. This phenomenon occurs because of several interrelated factors, including building design, regional distribution of land uses, and transportation mode choices. Each factor is influenced by land-use regulations deployed by local and state governments.
Buildings themselves contribute significantly to greenhouse gas emissions because of how they are designed. Housing units that share walls, like townhouses or apartments, tend to use less energy because they can better retain heat. But many localities allow only single-family homes to be built in many neighborhoods, and these homes tend to have a difficult time conserving heat. Homes that rely on natural gas for heat and cooking release greenhouse gases directly into the atmosphere.
Our communities’ layouts, shaped by land-use policies like zoning codes and often designed primarily around cars, inform our travel behaviors. Areas with only single-family homes—where day-care centers and groceries are prohibited by the land-use code—likely require a car to get around. People travel more miles by car in places that are less densely populated.
Personal automobiles are the largest contributor to transport-sector emissions overall, and they emit far more emissions per mile than buses, light rail, or bikes, even when accounting for infrastructure construction and maintenance.
Leveraging land-use regulations to reduce greenhouse gas emissions
So you have your single-family home, your Suburban, and your long commute, not to mention all of those errands. Although swapping out the Suburban for a more gas-efficient car, taking fewer car trips, or moving into a more conveniently located home might eliminate some pollutants, you probably have little choice in the matter.
The average home in Signal Hill is about one-third of the price as one closer to jobs, work, and good public transportation options. Living in Santa Monica could mean 15,000 fewer commuting miles per year, 7.4 fewer metric tons of carbon dioxide released into the air, and a much more walkable lifestyle—but, with the average home valued at about $1.5 million, it’s just not in the budget.
Reducing transportation and building emissions for everyone requires political and policymaking action. Policymakers can leverage reforms to improve constituents’ quality of life while mitigating human contributions to climate change.
Many cities are already making strides on reducing emissions through land use. Minneapolis’s 2040 Comprehensive Plan explicitly centers mitigating climate change and making community facilities transit accessible. But state and federal governments can also lead, particularly in the context of the 2021 Infrastructure Investment and Jobs Act, a trillion-dollar law that will fund transportation and energy projects nationwide.
Several best practices for federal, state, and local policymakers stand out:
- The federal government and states can encourage or require local governments to develop zoning codes that allow the construction of more neighborhoods with higher-density housing. This change can reduce building and transportation emissions by bringing people closer to daily necessities, like employment, grocery stores, schools, and recreation. The Biden administration has recently noted that it will leverage transportation grants to reward communities that achieve these goals. A more ambitious approach would mandate that localities receiving transportation funds show progress in this direction.
- States can require even the wealthiest municipalities to take on their fair share of affordable housing, making it more feasible for families to live in communities with easier access to daily needs. And states can require that any new transportation infrastructure is designed to reduce emissions.
- Local governments can alter their zoning codes by eliminating or reducing parking requirements, which have been shown to encourage car ownership and personal automobile travel. They can also require all-electric cooking and heating in new buildings, which reduces emissions from natural gas.
- Regional governments can institute growth boundaries that facilitate increases in development density while reducing construction on land previously used for agriculture or natural preserves. The Portland, Oregon, regional urban growth boundary curbs sprawl and lowers greenhouse gas emissions.
Any effort to promote climate-friendly land uses must consider broadening equity as a primary goal. Dense new developments around public transportation may attract more high-income families. Although these families may be less car dependent than if they lived elsewhere, they still travel more by car than households with lower incomes who have access to transit. Evidence shows income is the greatest correlate with emissions—so a dense suburb filled with wealthy people isn’t necessarily a clean one. Land-use planning should include provisions for affordable housing linked with transit services so greenhouse gas emissions can be minimized.
There are no easy answers for our friend in Signal Hill. Policymakers who care about people like her can work to ensure she has the ability—if she wants—to move to places like Santa Monica, where she’d have the option of walking more. And she can fight for land-use changes in her community that allow her to move to a more energy-efficient home or take more trips without a car.