China's Greenest Cities, and Its Brownest: No Match for San Diego

In a new working paper called “The Greenness of China: Household Carbon Dioxide Emissions and Urban Development,” Siqi Zheng, Rui Wang, Edward L. Glaeser, and Matthew E. Kahn rank 74 Chinese cities in terms of their household carbon footprints (abstract here; pdf here).

Here are the “greenest”: Huanian, Suqian, Haikou, Nantong, Nanchang, Taizhou, Zhengjian, Shaoxing, Xining, and Xuzhou.

And here are the “brownest”: Daqing, Mudanjiang, Beijing, Qiqihaer, Yingchuan, Shenyang, Haerbin, Dalian, Baotou, and Liaoyang.

Along the way, the researchers make a lot of important points — that the Chinese proportion of emissions from residential and transportation, e.g., is far lower than the proportion in the U.S. And of course that carbon emissions in the U.S. are roughly 5 times per capita the current rate in China (although that ratio is expected to shrink, and hard).

So just how far apart are residential emissions in the U.S. and China? As the authors write:

Even in the dirtiest city (Daqing), a standardized household produces only one-fifth of that in America’s greenest city (San Diego).

Samurai Scientist

What I want to know is how much of the pollution 'coming out of China' is from smokestacks belonging to U.S.-owned factories. My guess is 60-70%.


How does it work that per household the lowest in the US is 5x the highest in china, yet the ratio of the total averages are also 5x?


I live in San Diego, and it's news to me that it is the "greenest" city. Anyone know where that designation comes from? Sounds very dubious.

Hong Zhou

@ninth: if you have read Mr. Dubner's text more carefully you would know why. The "residential" emission is what you emit by virtue of doing what you do around your household. There are of course non-residential components to a country's emission: industry for example, or public transportation.

What the data shows is what we already know for a long time: China emits disproportionally more CO2 from its industry, a large part of which works to produce goods for the USA, rather than for the benefit of its own people. Put it another way, the emission that directly goes to the _benefit_ of its people is way _lower_ than 1/5 of the emission in the US going to the benefit of _its_ people, per capita.

Given that this is so, I wonder if the "re-balancing" of the global economy - that china consumes more of its own products and exports less - could offset the speed at which chinese per capita emission catches up with the US?



San Diego is Americas Greenest city ..?
Have been in SanDiego for quite a while .. havent heard of this before.. source of this info please..


The PDF link is dead. Try this link (MS Word .doc):


Samurai - U.S. owned factories??? Did I just nod out and wake up in 1910?


San Diego is not surprising as the greenest. A large proportion of household energy use is spent on heating and cooling. As San Diego is blessed with a near perfect year-round climate, heating and cooling is minimal.

matthew e. kahn

Here is the current version of the paper.

Our measure of "a green city" is based on a household's carbon dioxide emissions from transport, electricity, and heating. San Diego's temperate climate and clean electric utilities help it to excel in relative terms as a "green city".

On an aesthetics front, San Diego looks pretty green to me. My son enjoyed his 8th birthday at Seaworld.


There's more to pollution than just carbon dioxide. My friends in Macau (not a particularly polluted place by Chinese standards) need to sweep their floors twice a day because of all the grit and grime in the air. Beijing is so hazy that you often go weeks without seeing your shadow.

In the US, we don't think about visible pollution much any more, instead focusing on the chemical compounds that are poisoning us or heating the planet, but it's a very real problem in China.


It'd be interesting to map those cities. Seems the brownest ones concentrate in the NE...


With climate change now such a popular issue, "pollution" no longer refers to things that are unhealthy to breathe/ingest (toxic chemicals like lead, or particulate matter), but instead refers simply to carbon dioxide. Who cares if people are dying of asthma or lead poisoning? What matters is climate change!!

David Hodgkinson

How is CO2 "dirty"?

As the olympics in Beijing proved, shutting down truly dirty industry improved the quality of life no end.

And as other commenters pointed out, this is a somwhat disingenuous compariston.


I don't know exactly what is the household carbon footprints used in the study.
I do know the air quality in any city in US is a lot cleaner than the greenest in China. I was in six cities in China last year. I rarely saw clear blue sky over there during a 15 days trip.


'dirty' is a purposely misleading and counterproductive word to be using here. I have never been to a city in the US (no, not even Detroit, Pittsburgh, or Houston) that was anywhere near as filthy as industrial Chinese cities (and the air quality, oh my god, just step outside for a minute and you'll be hacking up crap for days).

I know the study says carbon footprint clearly, but from the comments (and from my own reaction), using 'dirty' just confuses things and mentally disposes me to poo poo the whole thing EVEN when I know better.

Stephen Keith

Having lived in Dalian, China for the past three years, I can attest a bit as to why the per capita Chinese carbon footprint is five times less than the U.S. First, almost no one has a clothes dryer or dishwasher. A building must be at least seven stories tall to have an elevator. The heat in most buildings comes on Nov. 15 and is shut off on March 15. Buildings south of the Yangtze River have no heat at all. Of my 420 university students, not one has an automobile and only 8 have driver's licenses. University students may not bring TVs, hair dryers, microwaves, or mini-refrigerators to their dorm rooms and they have no hot water in their dorm rooms. The electricity to dorm rooms is cut every night at 11 and If students use more than their allocation of electricity per month, it is shut off. Nearly everyone in China wears long underwear in the winter because buildings are minimally heated. People are expected to dress accordingly.

All of this is going to change as China becomes more "western-like".

BTW, I was surprised to read that Dalian is on the list of brownest cities because it doesn't seem polluted at all to me.



I'm sorry, but how can we write anything in good faith about China without mentioning 1 billion people living without human rights, enduring atrocities, and horrendous working conditions?

Greener China

Interesting piece of research that would come as no real surprise to those of us from the US and living in China

Where I disagree on some levels is that while the authors move past residential buildings as a source of emissions, they fail to address the fact that while they are not the "emitter", it is the energy demand from these buildings that creates the emissions, and while personal transportation is not the leading transport emitter today, China is on the path to that becoming a real problem that only adds to the existing systemic issues that the economy faces.

@samurai - there were 3 studies published on the link between exports from China and emissions. Ranges were 40-60% depending on several constraints



How can you call a place "green" that is literally brown half the year (when it's not on fire)? And San Diego's vaunted mild climate only applies in the narrow swath next to the ocean. Inland, where most of the population lives, you'll want A/C from June to October, and a bit of heat in winter.

Winter here is actually nice, btw; you can see more than a mile and even breathe the air some days.

Sunny Kalsi

Wondering if Chinese society is fragmented into the "haves" and "have-nots", with the former actually spending western equivalent amounts, and the latter bringing the average down. Alternately, is it some aspect of their society which makes them naturally greener (e.g. maybe they live closer together or something, which allows them to share heating costs? Cooking different kinds of food, etc?)

Unfortunately "transport represents a smaller share of [chinese household] emissions" does not answer the question in any absolute way.