Here’s how city dwellers can reduce greenhouse gas emissions and limit global warming

Shoppers check out clothing for sale in downtown Los Angeles. Reducing the number of new clothing items to eight or even three per person per year would help reduce greenhouse gas emissions tied to urban consumption.
(Ana Venegas / For The Times)

It’s no secret that city folk like to eat, shop and travel. But all that consumption adds up to a hefty climate bill.

On the flip side, that means urbanites have a lot of power to rein in greenhouse gas emissions. By changing their diets, their purchasing habits and how they get around, city dwellers can help avert the worst effects of warming.

A new report from the C40 Cities network — a coalition of nearly 100 local governments committed to addressing climate change — offers a sweeping action plan for city leaders and residents to reduce the emissions associated with their consumption. Together with other urban climate initiatives, these measures would allow C40 cities to achieve 35% of the emissions cuts the world needs from them to meet international climate targets.


“Cities can do a massive amount,” said Tom Bailey, head of research at C40 and a lead author of the report. “It’s actually quite a wonderful opportunity.”

The reason cities have so much sway is that they are responsible for up to 70% of the greenhouse gases that are pumped into the atmosphere, according to the United Nations.

Some of those emissions come from the tailpipes of cars stuck in bumper-to-bumper traffic and the power plants that keep our iPhones charged. Others are released in distant lands where our shoes, medicines and computers are made.

Until recently, these consumption-related emissions weren’t included in most cities’ accounting, since they occur outside city limits. Adding them up makes urban carbon footprints even bigger — and uncovers new avenues for city leaders and residents to combat climate change.

The new report, jointly produced by C40, the consulting firm Arup, and researchers at the University of Leeds in England, focused on cities in the C40 network. They include Los Angeles, San Francisco and New York (former mayor Michael R. Bloomberg is president of C40’s board) as well as international hubs like Beijing, Moscow, Dubai and Sao Paolo, Brazil.

Together, consumption in these cities accounts for more than 10% of the world’s total greenhouse gas emissions.


Cities are increasingly home to the wealthiest people, who tend to consume more, and thus have bigger carbon footprints, Bailey said. By 2050, consumption-related emissions are projected to nearly double as cities grow even bigger and more affluent.

That’s why dealing with climate change will require getting a handle on urban consumption, said John Barrett, an economist at the University of Leeds who contributed to the report.

“We can’t ignore demand,” he said.

Wealthy cities in the Northern Hemisphere have to take the most dramatic action. Already, the consumption habits of a C40 resident in a rich country like the United States or Japan give her a carbon footprint more than four times bigger than her counterpart in a C40 city in Africa or Southeast Asia.

These well-off urban dwellers will have to eliminate two-thirds of their consumption-related emissions by 2030 to stay on track to limit global warming to 1.5 degrees Celsius above preindustrial temperatures, the most ambitious goal of the Paris climate accord. (At the same time, low-income residents of cities like Nairobi, Kenya, and Delhi, India, actually have to increase consumption to meet their basic needs.)

It sounds like a tall order, but the report lays out a few key steps that, together, could deliver 20% of cities’ necessary emissions cuts. And the good news is that many are things that individuals can do right now.

For instance, eating less meat and dairy and reducing food waste would cut cities’ food-related emissions in half. (Local governments could encourage these changes by launching Meatless Monday campaigns in public schools and creating community gardens, the report authors suggested.)

No one has to go vegan, although that couldn’t hurt. The report found that cities would be off to a good start if residents reduce meat consumption to 35 pounds per year (compared to the current U.S. average of 222 pounds) and cut their annual dairy consumption to 200 pounds (down from nearly 650 pounds).

Such changes would produce significant health benefits too; the authors estimated that shifting toward a plant-based diet would prevent 170,000 deaths due to heart disease, cancer and other ailments in C40 cities each year.

The report also recommended changes to our shopping habits, like extending the lifetime of computers and other electronic devices, and buying fewer clothes (the authors suggest no more than eight items per person per year as a progressive target and three items as an aggressive goal).

That can be a challenge, since many people want to keep up with ever-changing trends, said Stephanie Pincetl, director of the California Center for Sustainable Communities at UCLA, who was not involved in the report.

Pincetl recommends buying high-quality items that will last a long time. “It sounds like deprivation, but it’s also a way to make your consumption much more thoughtful.”

Other measures listed in the report will fall on city governments more than individual residents, like incentivizing better building practices.

By using materials more efficiently, substituting green alternatives like sustainable timber or low-carbon cement, and ensuring that buildings are fully occupied, cities could reduce construction-related emissions 44% by 2050, according to the analysis.

As a bonus, these measures would also lower the cost of a new apartment by $10,000 in New York and by $15,000 in London, the report found.

“That makes construction and infrastructure a really exciting opportunity,” Barrett said. “It ticks all the boxes.”

Reducing car ownership would help shrink cities’ emissions as well. Not only does burning gasoline produce carbon dioxide, just building a car racks up a big carbon footprint due to the impact of mining and manufacturing its components.

Convincing urbanites to abandon their cars will likely require government policies to promote alternative modes of transportation. And it’s particularly important in a city like Los Angeles, Pincetl said. “We can create a totally transit-viable region. But we have to be willing to combat the car.”

The report also singles out flying as a major source of urban emissions, and one that won’t get greener anytime soon. Air travel is growing far faster than progress on electric planes and low-carbon jet fuel, Bailey said.

So the authors recommend that city dwellers cut back on the number of short flights covering less than 1,000 miles (think L.A. to Portland, Ore.) to one every two years, and to choose options like trains instead.

Although these measures would go a long way, they are not enough to bring urban emissions in line with global climate targets, the report found.

Customers enjoy lunch at a restaurant in Venice. Cutting back on meat and dairy consumption would help cities reduce greenhouse gas emissions associated with food, according to the report.
(Gary Friedman / Los Angeles Times)

Cities still have to transition to renewable energy, make buildings more efficient and build low-carbon transportation options. Along with changes in consumption habits, these kinds of efforts would get C40 cities one-third of the way toward their emissions targets.

Beyond that, cities will need help from national governments, which are responsible for things like moving power grids to clean energy sources. That would reduce the carbon footprint of the things city-dwellers consume, no matter where they’re made.

If countries follow through with the commitments they’ve already made under the Paris agreement, C40 cities could accomplish 70% of their needed emissions reductions. Closing the rest of that gap — something that must happen by 2050 to hit the 1.5-degree Celsius temperature target — would require even more aggressive actions across the board.

Cutting consumption-related emissions may ultimately mean rethinking the growth-oriented nature of our modern economies, Pincetl said.

“What reducing consumption implies is a reduction of economic activity,” she said. “And in a capitalist economic system, it’s a little scary for people to think about that kind of change.”

Cities have their work cut out for them but many show encouraging signs. Already, 27 of the C40 cities have seen the emissions produced within their boundaries begin to drop. San Francisco has reduced its carbon footprint by 36% since 1990 and aims to be carbon-neutral by 2050. In April, Mayor Eric Garcetti unrolled his version of the Green New Deal, which would put Los Angeles on the same path.

Bailey said he hopes the new report will give city leaders and residents even more ideas for addressing climate change, and help them see just how much they can do.

“This is a conversation starter,” he said.