TRONDHEIM, Norway, May 31, 2018 (ENS) – Seoul, South Korea, with its 21 million people, leads the world in its global carbon footprint, finds a new study that ranks 13,000 cities globally based on their carbon footprints. A city’s carbon footprint is the total amount of the heat-trapping greenhouse gas carbon dioxide it directly or indirectly produces.
The city of Guangzhou, China, with a population of 44 million, is number two on the list; and New York City, with its 13.6 million people, is number three on the list of cities with the largest carbon footprints.
Researchers from the Norwegian University of Science and Technology have surveyed the carbon footprints of 13,000 cities worldwide. This is the first time anyone has drawn a complete map of the potential for carbon footprint reductions from cities.
“The Gridded Global Model of City Footprints” downscales national carbon footprints into a gridded model using data from the year 2013 on population, purchasing power, and existing subnational carbon footprint studies from the United States, China, the European Union, and Japan and national data for other countries.
The paper’s lead author, Daniel Moran, says he was surprised at just how concentrated carbon footprints are.
“The top 100 highest-footprint cities worldwide drive roughly 20 percent of the global carbon footprint,” Moran said. “This means concerted action by a small number of local mayors and governments can significantly reduce national total carbon footprints.”
The results of their work have just been published in the journal “Environmental Research Letters.”
The researchers have also created a website, where users can check the carbon footprint of any large city in the world.
The study finds that the highest emitting 100 urban areas account for 18 percent of the global carbon footprint.
While many of the cities with the highest footprints are in countries with high carbon footprints, 41 of the top 200, such as Dhaka, Cairo, Lima, are in countries where total and per capita emissions are low, such as Senegal, Egypt, and Peru.
In these cities population and affluence combine to drive footprints at a scale similar to those of cities in high-income countries.
Here, Moran says, population and affluence in the urban areas combine to drive footprints at a similar scale as counterparts in the highest income countries.
“Downtown Dhaka is a bustling place. The decisions made there today lock in emissions for the next 50 years,” says Moran.
The researchers were also able to see the effect of wealthy enclaves, particularly in the United States and in China, Moran said.
“The fact that carbon footprints are highly concentrated in affluent cities means that targeted measures in a few places and by selected coalitions can have a large effect covering important consumption hotspots,” Moran said.
Mayors and citizens may also be willing to take more radical steps, such as switching the whole city over to green electricity, restricting private cars in the city center, or aggressively rewarding vehicle electrification, the researchers suggest.
Moran says that compared to countries, cities and local governments are often more nimble and can target the most effective solutions to carbon pollution in different districts and demographic segments.