Current conversations about urban sustainability are too narrowly focused, ignoring regional and global impacts and leaving out key grassroots groups with social justice agendas. That’s according to a new commentary published in Nature from Daniel Aldana Cohen of the University of Pennsylvania, along with David Wachsmuth of McGill University and Hillary Angelo of the University of California, Santa Cruz.

“We need to think about sustainability in a way that aligns with how the world really works right now,” said Cohen, an assistant professor in the Sociology Department of Penn’s School of Arts & Sciences. “The social and technical agendas really have to move hand in hand. A broader approach to sustainability policy would be both more effective and more equitable.”

With their varied backgrounds, the researchers saw a unique opportunity to frame the issue in a new way, particularly in light of the October United Nations Urban Habitat meeting, with its focus on incorporating sustainability into a “New Urban Agenda” for the next 20 years. The researchers presented two examples of key changes they feel would move urban sustainability forward.

The first deals with how we measure a city’s carbon footprint. Right now, a jurisdiction’s border determines its emission responsibilities, meaning what happens inside that arbitrary boundary gets counted but nothing more. Yet preliminary studies show that “the vast majority of emissions caused by local activity actually take place outside of city limits,” Cohen said.

For example, say someone who lives in Philadelphia owns a laptop computer. The emissions generated to power that device when it’s plugged in increase the city’s total, but factors that went into building it do not. On a large scale, that can add up, like it has in San Francisco, a city rare in that it has examined its global carbon footprint.

Nearly 80 percent of San Francisco’s total released greenhouse gas emissions come from beyond city limits. With the exception of vehicles/parts and appliances such as air conditioning, emissions derived from elsewhere far exceed those generated within. Yet urban climate policies focus almost exclusively on emissions that occur inside city limits.

Instead, the researchers argue, we should use what’s called a consumption-based footprint analysis. This analysis accounts for the emissions associated with airplane travel and energy used to produce goods and services, from food to iPhones, that urban consumers and organizations use.

“Urban low-carbon policies now need to go beyond just density and mobility issues and also include strategies to reduce consumption in wealthier communities,” Cohen said.

Second, the urban sustainability conversation needs to expand to include more voices and to incorporate a social agenda at its core.

“If you’re going to take equity seriously, you have to bring everyone to the table,” Cohen said. “That includes housing-oriented groups, other economic justice groups, who might not talk about climate change in every press release. You have to think about sustainability broadly, not just what environmentalists are saying.”

The key is to shift the focus from a few well-known areas of urban climate policy to an all-encompassing agenda. “Focusing on dense cities and their affluent areas ignores social movements and their advocacy for quality-of-life issues such as housing and commuting, which have direct ecological consequences,” the researchers wrote in the paper. “Targeting specific districts ignores the often negative regional and global impacts of local environmental, or ‘greening’ improvements.”

Instead of redistributing ecological pollution from prosperous to deprived parts of town, improving life for the well-off of a city and not its poor, it is now necessary to fold in social movements locally, while keeping tabs on global ecological impacts.

“We need to think more holistically, more intelligently about sustainability policy,” Cohen said. “That is really key to making sure that everyone benefits.”