Big cities are not always biggest polluters

Jan 26, 2011
The sun sets over the Manhattan skyline. Big cities like New York, London and Shanghai send less pollution into the atmosphere per capita than places like Denver and Rotterdam, said a study released Tuesday.

Big cities like New York, London and Shanghai send less pollution into the atmosphere per capita than places like Denver and Rotterdam, said a study released Tuesday.

Researchers examined data from 100 cities in 33 nations for clues about which were the biggest and why, according to the report in the peer-reviewed journal Environment and Urbanization.

While cities across the world were to blame for around 71 percent of the world's greenhouse gas emissions, urban dwellers who can use public transport rather than drive helped to lower per capita emissions in some cities.

For instance, the sprawling western US city of Denver's per capita emissions were nearly double those in New York City, home to eight million inhabitants and a gritty, heavily used subway system.

"This is mainly attributable to New York's greater density and much lower reliance on the automobile for commuting," said the study.

Even Denver's per capita emissions, at 21.5 tonnes of carbon dioxide equivalent, were sharply higher than Shanghai at 11.2 tCO2e, Paris (5.2) and Athens (10.4).

Chinese cities stood out from the rest of the world because their average emissions were far higher -- for instance with Beijing emitting 10.1 tonnes of equivalent -- than the country as a whole which emits 3.4 tCO2e.

"This reflects the high reliance on for , a significant industrial base within many cities and a relatively poor and large rural population," said the study.

Looking at greenhouse gas emissions per GDP, researchers found that "citizens of Tokyo are 5.6 times more efficient than Canadians."

The port city of Rotterdam in the Netherlands got a particularly bad rap because of its links to shipping and heavy industry.

"Rotterdam's per capita value of 29.8 tCO2e versus 12.67 tCO2e for the Netherlands reflects the large impact of the city's port in attracting industry, as well as fuelling of ships," said the study.

"This is similar to cities with busy airports and highlights the need to view the city-based GHG emissions cautiously and holistically."

Other trends included the tendency for cities in cold climates to have higher emissions, and for poor and middle income countries to have lower emissions per capita than wealthy countries.

When researchers looked at cities in Asia, Latin America and Africa, they found low emissions per person across the board.

"This paper reminds us that it is the world's wealthiest cities and their wealthiest inhabitants that cause unsustainable levels of , not cities in general," said editor David Satterthwaite, a senior fellow at the International Institute for Environment and Development.

"Most cities in Africa, Asia and Latin America have low emissions per person. The challenge for them is to keep these emissions low even as their wealth grows."

An analysis of three neighborhoods in Toronto found that the highest emissions came from the suburbs, where streets are lined with large single family homes that are far from commercial centers.

The lowest levels of emissions came from areas with apartment complexes in walking distance to shopping and transit.

Explore further: Study finds accelerated soil carbon loss, increasing the rate of climate change

add to favorites email to friend print save as pdf

Related Stories

Reducing CO2 through technology and smart growth

Feb 11, 2009

A Georgia Tech City and Regional Planning study on climate change, published February 10, 2009 online by Environmental Science and Technology, shows that "smart growth" combined with the use of hybrid vehicl ...

Recommended for you

Untangling Brazil's controversial new forest code

15 minutes ago

Approved in 2012, Brazil's new Forest Code has few admirers. Agricultural interests argue that it threatens the livelihoods of farmers. Environmentalists counter that it imperils millions of hectares of forest, ...

China toughens environment law to target polluters

15 minutes ago

China on Thursday passed the first amendment to its environment protection law in 25 years, imposing tougher penalties on polluters after the government called for a "war" on pollution.

Sea floor conditions mimicked for drilling platforms

4 hours ago

Mobile jack-up drilling platforms used in the oil and gas industry are at risk of rejection before installation due to their use in harsher environments and deeper waters—but University of WA scientists ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

Taubus
not rated yet Jan 26, 2011
The way they attributed per capita pollution seems quite unrelevant. I mean, fuelling ships is attributed to the inhabitants of Rotterdam?
It is quite likely that this fuel is used for/by people from elsewhere, to ship goods. Also, the actual pollution is unlikely to take place in Rotterdam, it will happen on sea. So why count it as city based pollution for Rotterdam?

JBaeckel
not rated yet Jan 28, 2011
@Taubus
I don't think the article mentioned how they got their numbers. If they got their numbers from testing the actual air in Rotterdam then where the fuel is combusted is a red herring and mentioning the fact that Rotterdam is a busy port is likely more of a "This is probably why the per capita pollution is worse here".

More news stories

Untangling Brazil's controversial new forest code

Approved in 2012, Brazil's new Forest Code has few admirers. Agricultural interests argue that it threatens the livelihoods of farmers. Environmentalists counter that it imperils millions of hectares of forest, ...

How productive are the ore factories in the deep sea?

About ten years after the first moon landing, scientists on earth made a discovery that proved that our home planet still holds a lot of surprises in store for us. Looking through the portholes of the submersible ...

Genetic code of the deadly tsetse fly unraveled

Mining the genome of the disease-transmitting tsetse fly, researchers have revealed the genetic adaptions that allow it to have such unique biology and transmit disease to both humans and animals.

Ocean microbes display remarkable genetic diversity

The smallest, most abundant marine microbe, Prochlorococcus, is a photosynthetic bacteria species essential to the marine ecosystem. An estimated billion billion billion of the single-cell creatures live i ...