Although they are only a couple weeks old, two zoning bills are already getting significant attention. The legislation, submitted to Philadelphia City Council by Council President Darrell L. Clarke, has support from Council members Jannie Blackwell, Kenyatta Johnson, Curtis Jones Jr., Cherelle L. Parker, Brian O’Neill, and Maria Quiñones-Sánchez.

These bills take aim at 2011 zoning changes, that increased the types of buildings allowed in the city, and reduced the amount of parking required with each new development. The first proposed bill would establish a commission to reexamine the zoning code. The second proposed bill would limit the ability of the Zoning Board of Adjustment to grant variances specifically for multifamily housing in new, specifically designated “Single Family Preservation Districts.”

As covered in The Inquirer, this effort would have implications for Philadelphia’s affordability and urban design. Left unmentioned is the damage these changes would inflict on the climate.

Increasing urban density is a pivotal strategy in the fight against climate change. Dense cities produce less carbon emissions per person. Why is this? When more people, jobs, and activities concentrate in a smaller space, we use energy more efficiently to serve them.

Consider transportation, which is the leading cause of carbon emissions in the United States. The more people, jobs, and activities in one spot, the more sense it makes for SEPTA to provide better service to that area. The more people riding SEPTA, the fewer people who are driving. Per person, a train or bus emits far less carbon than a personal car.

Fundamentally, dense urban places make it less carbon-intensive to provide basic goods and services. Philadelphia’s moderately dense older neighborhoods on all sides of Center City support markets, barbers, tailors, locksmiths, and other useful businesses. Although, as he famously claimed, Clarke may drive to the corner store, for many Philadelphians, everyday essentials are a short walk away. In more sprawling places, like much of Philadelphia’s suburbs, completing these basic errands requires a car trip.

Density provides environmental benefits when you might not expect it. For example, take internet shopping. Package delivery trucks are everywhere in Philadelphia, driving circuitous routes and idling in the middle of streets. But in South Philadelphia, at the corner of South and 23rd, retail giant Amazon has recently opened up a storefront. Instead of a smog-puffing box truck taking every Amazon package to every door, orders are shipped to this one location for residents to collect. The density of people around this location within walking or bicycling distance is what makes this kind of efficient system possible.

Another major source of carbon emission is the need to heat and cool buildings. Here, too, urban density makes a difference. When we live in smaller spaces, it takes less energy to make them comfortable. Imagine a stand-alone building that is home to a single couple. Now imagine an identical building subdivided into a triplex, with a couple living in each unit. On a muggy Philadelphia summer day, the couple in the first building need just about as much energy to keep their building cool as the six people living in the triplex. Multiply this effect across an entire city, and the savings are substantial.

The well-publicized 2018 Intergovernmental Panel on Climate Change report, which warned that humanity had just 12 years to make fundamental changes to avert catastrophe, marshaled considerable evidence to argue that urban density is an essential tool for combating carbon emissions. In fact, a 2018 UC Berkeley study of 700 California cities found that increasing urban development could do more to reduce carbon emissions than any other common strategy.

Philadelphia’s leaders frequently talk about mitigating climate change. In fact, the proposed legislation to create a review board briefly mentions it. But the Council president’s companion bill, and his public statements, make clear that the motivation for these initiatives is to limit multifamily developments and mandate more parking. As a result, this legislation threatens to become a major step backward. There’s a reason why cities including Buffalo, Minneapolis, and San Diego, are eliminating minimum parking laws and significantly increasing the types of new buildings allowed in zoning.

If Philadelphia is serious about combating climate change, it will reject the bill to restrict multifamily development, and ensure that any zoning review committee is empowered to do its own research.

That doesn’t mean that anyone who is unsatisfied with the current pace, locations, and style of Philadelphia’s recent growth should hold their tongue. But it does mean that when we have a citywide conversation about land-use policy, we need to start from the position that we have a moral responsibility to add more density of homes, jobs, and activities — especially in our most walkable, bikeable, and transit-friendly neighborhoods — not less.

Alex Schieferdecker is an urban planner who lives and works in Philadelphia.