The 2015 United Nations Climate Change Conference, kicking off Monday in Paris, may well be the most consequential climate summit in history.
While previous climate summits in Kyoto and Copenhagen buckled under the weight of binding, universal agreements, the Paris talks are largely built around what countries and other actors are willing to pledge on their own. Such voluntary commitments differ from government to government, but together may represent the biggest global response to climate change to date.
Importantly, a big part of that response will come from cities. Alongside the 190 or so world leaders, hundreds of mayors from around the world will also gather in Paris to pledge dramatic reductions in greenhouse gases at the local level. This is thanks to the Compact of Mayors, a global network of cities launched last year by UN General-Secretary Ban-Ki Moon in partnership with former New York City Mayor Michael Bloomberg.
The participating cities, which include New York, London, and Tokyo, represent more than 550 million people and a full quarter of the world's economy. And while each city’s plan is little different, in many cases they far exceed the intended nationally determined contributions made by individual nations.
For example, both New York and San Francisco have vowed to cut their emissions to 80 percent below 1990 levels by 2050. That’s a far cry from the U.S. government’s commitment to slash emissions to 26-to-28 percent below 2005 levels by 2025.
“We’re in better shape going into Paris than we were going into Copenhagen largely because of the progress cities have made,” declared Bloomberg in a November report by the C40 Cities Climate Leadership Group, one of the three groups that founded the Compact of Mayors. (The others include the International Council for Environmental Initiatives and United Cities and Local Governments.) “In many ways, the Paris summit has already succeeded, I think, where others have failed.”
But beyond such lofty rhetoric, exactly what impact will cities have on climate change is hard to know. As with the promises made by nations, pledges made through the Compact of Mayors differ widely in scope, goals, and how they will measure progress. Cities even differ on such questions as what kinds of emissions should be counted within a municipality. And because many of the stated targets are not legally binding, it’s an open question how they will be implemented and enforced over the long term.
“Accountability has been a big challenge,” says Angel Hsu, a professor at the Yale School of Forestry & Environmental Studies. Since cities will define their own standards for measuring emissions, making cuts, documenting improvements, and reporting the results, it’s not clear how they’ll follow through on their ambitious goals.
“In the absence of a binding treaty,” says Hsu, “how can we be assured that these actors will fulfill these pledges?”
In June, Hsu and her colleagues at the Yale School took a hard look at the feasabiliy of the climate plans proposed by cities. The results were less than encouraging. Of the more than 2,000 cities planning to cut emissions through networks like the Compact of Mayors, only 200 have spelled out specific mitigation plans and targets. Moreover, out of the 29 action statements made by such non-state networks like the Compact of Mayors, only eight had tied specific emission reduction targets to a particular year. Only two had identified specific funding sources.
A similar analysis of city-level plans by the International Governmental Panel on Climate Change (IPCC) last year concluded that “targets are often arbitrary and aspirational, neither reflecting mitigation potential nor implementation.” With little enforcement, cities may have comparably little incentive to make sure their ambitious goals are actually realized.
“I think the overall message was the need for additional data and additional reporting,” says Amy Weinfurter, another Yale School researcher who worked on the study with Hsu. And while Weinfurter expects that more data will become available as the plans are put into action, it’s unclear what they will show. “It’s a balancing act,” she adds. “You also don’t want to make the process so onerous that it discourages people; but accountability has been an issue.”
One of the issues that both the researchers at the Yale School and the IPCC pointed to is how such long-term commitments would fare as current mayors finish their terms and are replaced following elections. Right now, mayors in cities like Seattle, Minneapolis, and San Francisco are among the most progressive political leaders in the country. Spurred by profound demographic transitions throughout urban America, cities have in many ways become laboratories for progressive initiatives on wages, housing, and of course, climate. Given these trends, it may be unlikely that future mayors will disregard climate action plans hammered out now.
But Hsu remains skeptical. “I have very little faith in cities who say we’re going to reduce emissions by 2050,” she warns. “These commitments far outlast mayoral term limits.”
It’s not a new problem. As Hsu noted in a study earlier this year, negotiators at the 2002 World Sustainable Development Summit in Rio de Janeiro committed to more than 300 partnerships between states and such non-state actors as companies and cities. But by 2012, nearly two-thirds of those agreements had not yet been implemented. That same year, the Rio+20 Summit generated some 700-odd voluntary commitments that featured little in the way of accountability or common standards. “There was a lot of empty talk,” says Hsu, “but it was not paired with any implementation or action.”
Another problem is the wide variation in how cities measure carbon emissions. For example, many cities participating in the Compact of Mayors count only production-based emissions—that is, greenhouse gases that are generated within the city. Left out of these counts are activities taking place outside municipalities to serve city residents, such as fuel processing and supply chains to produce tennis shoes or smartphones. And the differences between what’s produced inside the city and outside it are not small. In San Francisco’s case, emissions total 5.3 million metric tons annually inside the city, compared with 21 million metric tons produced in the process of providing the goods and services that city residents depend on.
“You have two different viewpoints on what it means to have responsibility for greenhouse gas emissions,” says Elizabeth Stanton, who worked on numerous emissions inventories while serving as an analyst at Stockholm Environment Institute. While a production-based report will give you an idea of a place’s carbon footprint, Stanton explains, looking at consumption-based emissions offers a broader picture of that places’s position within the global economy. “In an area that’s affluent you should expect a consumption-based inventory to be far higher than production,” she notes.
There are good reasons, however, why cities shy away from consumption-based accounting. Doing an emissions inventory is difficult and costly, Stanton notes, and may yield unflattering results. “There’s a strategic element: Who wants to do a greenhouse inventory?” she says. “It’s a wonderful exercise, but it’s a little bit tricky because by doing that one’s perception of being green may be dented a little bit.”
Choosing between consumption- or production-based emissions also has policy implications. “The different methods will provide you with a different set of mitigation options,” says Christopher Jones, Program Director of the CoolClimate Network, a climate research program at the University of California, Berkeley. A production-based inventory, for instance, tends to give cities much more power to regulate and reduce greenhouse gases. After all, it’s much easier for a city to reduce emissions at a local power plant than to address the climate impact of a global supply chain.
But a consumption-based inventory also gives cities powerful tools to reduce their carbon footprint, says Jones. Focusing on consumption lets you explore a city’s broader pattern of consumer behavior, its impact, and how it might change through incentives or other programs. It can also highlight the impact of eating and buying local. “A consumption-based inventory sends a different message: Consumer demand drives emissions,” says Jones.
For instance, according to a 2010 study, as much as 23 percent of carbon emissions are traded internationally through global production and supply chains, a large share of them originating in China. As the study’s authors note, “the geographical separation of production and consumption complicates the fundamental questions of who is responsible for emissions and how the burden of mitigation ought to be shared.”
Focusing on one type of emissions over another also can have unintended consequences. “Very often what happens is that when you reduce production-based emissions, consumption-based emissions go up,” says Jones. “Ideally, it would be appropriate to have two lenses to evaluate your impact on climate change and then separate targets.” Although consumption-based inventories are gaining traction among local governments, only a handful of cities pledging to cut emissions have done one.
Not to mention the problem of overlap between city-level pledges to cut emissions and the national commitments already on the table. A study by the United Nations Environment Programme earlier this year found that, taken together, the overlap between the emissions cuts pledged by national and non-state players could total as much as 900 million metric tons. That comes to as much as one third of total non-state actions, and just over half of what UNEP estimated city-level commitments could contribute. Similarly, according to the World Resources Institute, the 176 or so country-level pledges are set to impact more than 95 percent of global emissions, potentially leaving little room for city-level action without significant overlap.
Cities and national governments are not always on the same page, moreover. In California, for one, governments at the city and state level have made commitments that go way beyond the U.S. target of a 26-to-28 percent emissions cut. But U.S. government officials have a tendency to subsume such cuts in their overall accounting of projected greenhouse gas reductions, says Hsu, as opposed to counting cities’ pledges as additional and complementary.
All that being said, cities are still uniquely positioned to confront the crisis of climate change. According to the United Nations Development Programme, more than 70 percent of global climate change prevention measures are undertaken by local governments. “There are real limitations in terms of what national-scale policy can do,” says Jones. “A top-down approach isn’t going to get us there fast enough. There’s a need for local engagement. Really what we’re talking about is culture change.”
As climate negotiators flock to Paris, the role of cities will be front and center. The nations convening in the City of Light, still recovering from the horrific terrorist attacks of November 13, have drafted some of the strongest climate plans on record. But the proposals still fall short of what’s needed to avert the most catastrophic impacts of climate change. Cities have taken an ambitious step toward slashing emissions further. But just how far non-state actors like cities can go in closing that gap remains to be seen.