Cities are not just where 3.5 billion of us live—they are where more than half of humanity uses electricity, drives cars, and throws out garbage, among myriad other activities that emit greenhouse gases. Now, a global coalition has released the first standardized method for measuring and reporting a given city’s greenhouse gas emissions. Called the Global Protocol for Community-Scale Greenhouse Gas Emission Inventories (GPC), the new standards were unveiled today at the United Nations’ ongoing climate negotiations in Lima.
Cities are responsible for 70% of global carbon dioxide emissions, says Wee Kean Fong, who led development of the GPC at the World Resources Institute—a nonprofit based in Washington, D.C.—in partnership with the C40 Cities Climate Leadership Group and Local Governments for Sustainability (ICLEI). But there has been no standardized way to measure and report an individual city’s emissions. That has impeded plans to reduce urban climate footprints and track the effectiveness of local policies designed to reduce emissions. “You can’t manage what you can’t measure,” Fong says.
A key element of the GPC is its recognition that a city may be responsible for gases emitted far outside its borders. Take power plants that burn fossil fuels to generate electricity, or landfills that receive solid waste, Fong says. Those can be located outside of a city, but their emissions are directly tied to urban activity. Holding cities accountable for such emissions may lead to some pushback when it comes to convincing them to adopt the GPC protocol, but it’s important for making sure measurements are accurate as possible, Fong says.
A key selling point is that 35 cities have already benefited from implementing the GPC during its pilot phase in 2012. In the months since, other cities have been test-driving the new standards. David Maleki, a climate change analyst with the Inter-American Development Bank’s Emerging and Sustainable Cities Initiative, helps cities in Latin America and the Caribbean use the protocol to figure out which sectors are responsible for most of their greenhouse gas emissions. These “[greenhouse gas] inventories are a very basic building block for taking climate action in cities,” he says. Rio de Janeiro, for example, used a draft of the GPC to determine that transportation was responsible for a whopping 39% of the city’s total emissions; that led the government to focus on expanding public transit to more efficiently shrink its carbon footprint. “Building a greenhouse gas emissions inventory enables city leaders to manage their emissions reduction efforts, allocate resources and develop comprehensive climate action plans,” said Rio de Janeiro mayor and C40 Chair Eduardo Paes said in a statement.
One lesson Fong and his team learned during the pilot program is that not every city is starting from the same place when it comes to measuring greenhouse gas emissions. Some cities, especially in the developing world, simply don’t have access to the kind of data needed for a comprehensive inventory; Maleki says he often works in places where the only emissions data available are on a national scale.
To try to make the GPC accessible to cities that may not have all the right data, Fong’s team designed two tiers of reporting. Both incorporate transportation within the city, stationary burning of fossil fuels, consumption of electricity, and emissions related to waste. The more advanced tier adds data about industrial processes, land use change, transportation that brings people into the city, and other indirect sources of emissions. “The GPC is a very inclusive protocol,” says Ana Marques, project coordinator of ICLEI’s Urban-LEDS project, which will help cities in developing countries apply the GPC. “It enables all cities to participate.”