Key Takeaway: Science for 1.5C Cities, a side-event held in UN’s basement last week, showcased the potential of new approach to climate change: letting cities take the lead.


Inside of a rock underneath Turku, a city of 330,000 in Finland, lies a wastewater treatment plant and heat-pump system that turns rubbish into energy. It generates ten times more power than it consumes. 

Half a world away in Mexico City, one of the world’s most polluted places, more than 20 million people anxiously hope for cleaner air while the government struggles to obtain electric buses.

These contrasts illustrate the opportunities and obstacles to a movement that environmentalists say may offer the best hope to reverse climate change: attacking climate change at a local level.

“Cities are going to be the implementers of a lot of the nationally determined commitments,” Cynthia Rosenzweig, co-director of Urban Climate Change Research Network and researcher with Columbia University’s Earth Institute, two of the event’s sponsors, told Karma. Cities’ willingness to experiment and practical forms of government put them in unique positions to fight climate change. They also play roles in overseeing their citizens’ health, and generate about 70% of the earth’s emissions, she said.

“They have this tremendous leadership potential,” she said, adding that their proximity to rising oceans also puts them at the cutting edge of making changes.

The debates were at the center of Science for 1.5C Cities, a meeting held during last week’s UN General Assembly. The Science 1.5 session, which drew scientists and politicians from around the world, addressed effects of climate change on metropolitan areas and the role cities might play in cutting greenhouse gas emissions. 

The session’s title comes from “Global Warming of 1.5C,” a report released last year by the Intergovernmental Panel on Climate Change that argued hundreds of millions of people could be spared the worst effects of climate change if temperature increases were kept under 1.5C.

“Cities are going to be the implementers of a lot of the nationally determined commitments.”

Despite the ideas shared and debated, the General Assembly ended without China, the U.S., Brazil or other major contributors to CO2 emissions committing to new clean-air initiatives. 

The 1.5C event was held in a UN basement, and covered topics such as sustainable agriculture in Nakuru County, Kenya to the need for social science to buttress ecologically conscious investments in infrastructure by Victoria, Canada.

Turku’s mayor, Minna Arve, said the city had made significant progress toward achieving its goal of carbon neutrality by 2029. Thanks in part to a close relationship between its public and private sector as well as a number of innovative initiatives, the city intends to be fully carbon neutral in 10 years. 

Diana Alarcón González, chief advisor to the government of Mexico City, sounded the meeting’s most urgent note of alarm when she described the challenges of purchasing electric buses. 

Mayor Arve’s and González’s comments illustrated how international funding, domestic politics, and local governance may enable or obstruct locally driven climate action.

Turku’s Virtues

In an interview after the event, Arve told Karma that Turku’s early success has stemmed largely from its control of many city-owned companies. “We have a lot of tools,” she said. Having municipal firms make it “easier to set the goals.”

Heating provider Turku Energia, the city’s largest source of emissions, has cut its noxious gases by replacing coal with wind and solar and overhauling its wastewater treatment. According to Risto Veivo, Turku’s development manager, the city’s underground wastewater plant.

Turku is also experimenting with a two-way heating process, which would allow consumers to sell unused energy back to the city for distribution or storage. A study by Turku University’s economics department found that the city now sends between 1% and 2% of waste to a landfill, with the rest recycled or used as energy, such as biogas.

Meanwhile, industrial and machinery emissions have declined 68% since 1990. Among the biggest contributors to this change has been Turku’s billion-dollar ship-building industry, whose newer vessels now use liquid natural gas, generating about half the emissions of traditional fuels. 

Risto Veivo, Turku’s development manager, said shipbuilders were simply responding to market forces. Some of their biggest customers are German cruise operators “who are serving the environmentally-conscious elderly German cruise customers,” he said.

Turku has also benefited from a $165 million loan it received in January from the European Investment Bank. The city used the money to create bicycle lines, support bike-to-work programs and implement new environmental standards for buildings.

But Arve rated politics as “the biggest issue” enabling sustainable development. Before Finland’s general election in April, parties from across the aisle announced a broad consensus on climate policy.

“Our politicians and parties have been very unanimously, all the time supporting this work,” Arve said.

Is the Market Enough?

Alarcón González was not as optimistic. She said Mexico City had not been able to find a way to reconcile environmental and socioeconomic concerns.

Also, the expense of some new programs has been prohibitive. The cost of one electric bus, according to Alarcón González, equals what the city spends on three to five diesel buses, which are the city’s largest source of emissions.

“We have major problems with inequality,” she said. “There are people in the periphery, the most vulnerable, who take about at least two hours to get to their jobs.”

Alarcón Gonzalez’s pointed call for funding at the end of her remarks appeared to go unheeded.  

In an interview afterward, Alarcón González told Karma how market-based solutions did not seem adequate. Other cities with electric bus systems, such as Frankfurt, have received substantial funding from their federal governments, said Alarcón González. Mexico City’s conversations with auto manufacturers have not been fruitful. 

“Money the Mexico City government does have, ”we are spending on repairing schools, reconstructing thousands of households affected by the earthquake,” she said.

Accounting for the Changes

Turku’s and Mexico City’s different experiences also reflect broader challenges and advantages. Mexico’s economy has been struggling and its credit rating was downgraded this year by Moody’s, Fitch, and Standard & Poor. That may have a trickle down effect on its largest city.

“You have to have the motivation for those people who are not driving with the passion of tackling climate change, but are more worried about their everyday life.”

But Turku’s credit rating is “very good,” said Veivo, helping the city get needed loans.  

Turku’s government has the luxury of taking a longer view with its policies. A report by the city’s “climate team” talks about climate investments being repaid within five to 15 years and generating profits after 10 or 20 years.

Still, Arve emphasized that good climate politics emphasize pragmatic gains. Climate initiatives can lead to greater efficiency, which saves money, Arve said. 

“You have to have the motivation for those people who are not driving with the passion of tackling climate change, but are more worried about their everyday life,” she said.