Do you have strong feelings about zoning regulations?

Odds are, probably not. This area of public policy can be arcane. But that doesn’t make it any less consequential, as an ongoing lawsuit shows.

The centerpiece of this lawsuit is Minneapolis 2040, an update to the city’s Comprehensive Plan. According to a city website, the Comprehensive Plan is “an important citywide policy document that provides direction for Minneapolis’ built, economic and natural environment.” The plan is updated every 10 years.

In addition to many other changes, the centerpiece of the plan is the abolition of single-family zoning citywide. This means duplexes and triplexes can now be constructed anywhere in the city that was previously only zoned for single-family homes.

But, a coalition of groups—including the Audubon Chapter of Minneapolis, Minnesota Citizens for the Protection of Migratory Birds and Smart Growth Minneapolis—says this plan will be harmful to the environment. According to Smart Growth’s website, they sued the city under the Minnesota Environmental Rights Act. The suit alleges the plan has the potential to, among other things, cause pollution, flooding and erosion, and reduce air quality, habitat and biodiversity.

Supporters of the plan say this assessment is incorrect. David Zoll teaches at the University of Minnesota Law School. He is also an attorney at a private law firm and helped submit a brief supporting the 2040 Plan on behalf of the organization Neighbors for More Neighbors, which advocates for loosening zoning regulations.

According to Zoll, the organizations who filed the lawsuit “didn’t demonstrate that there was a likelihood that the alleged harms would occur because they didn’t demonstrate there was a likelihood that there would be full build-out of the multifamily development that’s ostensibly authorized under the new comprehensive plan.”

Although, to be honest, this argument doesn’t quite sit right with me. While I agree that it’s unlikely every single-family home in Minneapolis will be converted into a triplex, it’s also the case that, the closer we get to that point, the greater the potential benefits of the plan are. Isn’t building denser housing the whole point?

Zoll also said that should projects authorized under the plan require environmental review, this will occur on a per-project basis. He said this could include a stormwater discharge permit, for example. “So, there’s a variety of approvals that a project goes through that would address whatever the potential environmental impacts. And a big enough project might trigger its own deed for a separate environmental impact statement,” Zoll said.

The lawsuit has been met with mixed success by the courts. In June, a Hennepin County judge put the 2040 Plan on hold. However, in July, that same judge decided to allow the implementation of the plan to continue.

To be frank, I don’t know nearly enough about the applicable laws here to render a judgment on this suit. Even the judge appears to be confused.

But I do feel comfortable saying that adding more housing, if it happens, will be extremely good for helping people afford a place to live. According to a 2018 paper published by the Furman Center for Real Estate and Urban Policy at New York University, “adding new homes moderates price increases and therefore makes housing more affordable to low- and moderate-income families.” A 2021 paper published by the Lewis Center for Regional Policy Studies at UCLA found this holds true at the neighborhood level, but the evidence base is much smaller.

Single-family zoning also has a long history of exacerbating segregation. These rules were first developed as a way to get around the prohibition of explicitly racist zoning rules, and they have continued to serve a similar purpose. In the Twin Cities today, the “metro’s Black population is concentrated in these areas zoned for multifamily housing,” according to a 2021 article from the Star Tribune.

As for the environment, it’s not as clear-cut. And it’s important to differentiate between effects on climate change and effects on conservation – whether denser housing emits more greenhouse gasses is a different question from what impact it would have on the local ecosystem. For their part, the Minnesota chapter of the Sierra Club supports the 2040 Plan. The Minnesota Center for Environmental Advocacy, on the other hand, isn’t taking a public position on the lawsuit, climate policy analyst Melissa Partin told me in an email.

According to a 2021 study published in the journal Buildings & Cities, there is strong consensus that those who live in denser areas emit fewer greenhouse gasses per person from transportation, heating and cooling. However, overall emissions are higher because there are more people, and there can be less capacity to address those emissions thanks to lower carbon sequestration.

A 2021 study published in the journal npj Urban Sustainability cautions that, while building denser housing doesn’t increase greenhouse gas emissions, building taller buildings does. So, from a climate perspective, it could be best to prioritize building housing that is dense, but not tall. It is worth noting, however, the 2040 Plan also increased some height minimums.

And then there’s conservation. The Buildings & Cities paper found density harms biodiversity, the local climate and other “ecological conditions.”

But this isn’t the whole story. Conrad Zbikowski is a communications strategist who works with Democratic candidates and volunteers with Neighbors for More Neighbors. “Having denser housing in Minneapolis in the urban core helps reduce the number of green acres that are redeveloped into housing in places like, you know, Maple Grove and Rogers, places like that, that destroy habitat for animals,” Zbikowski said.

A 2010 study of beetles in Canada suggested “building at a high density over a small area, rather than at a low density over a large area, minimizes the impacts of a given human population on carabid beetles.” A 2018 study in Australia found the optimal distribution of people for preserving the diversity of native bird species was somewhere between high-density and low-density, but more similar to high-density.

Of course, this is all assuming people actually build the new, denser housing that’s allowed under the 2040 Plan. Zbikowski was quick to point out various new developments. However, according to the Minneapolis branch of the Federal Reserve, permits for new multifamily units are down in comparison to what would’ve happened without the 2040 Plan, which is based on data from other cities.

Ultimately, I still support eliminating single-family zoning. We need to make sure that denser housing actually gets built and that it’s as affordable and environmentally friendly as possible.