A Solution for Climate Pollution?

Copenhagen used to be an industrial city. There were factories in the narrow streets and ships in the oil-stained harbor. Electricity came from smoke-emitting coal-fired power plants, and the air was smoggy.

Today, Denmark’s capital has been transformed into a much more environmentally friendly place. Offshore wind turbines generate much of the city’s electricity. Bicycle paths are three lanes wide on busy streets to accommodate the 43 percent of Copenhageners who regularly commute to work or school by bike. A new train line opening this year will put most residents within half a mile of a train station, reducing the need to drive.

To cut down on garbage, all apartment buildings now have eight different recycling bins so residents can recycle as much as possible. Nonrecyclable garbage goes to a high-tech incinerator, where it’s burned to generate heat for buildings.

Copenhagen used to be an industrial city. There were factories in the narrow streets and ships in the oil-stained harbor. Electricity came from smoke-emitting coal-fired power plants, and the air was smoggy.

But Denmark’s capital has been transformed. Today, it’s a much more environmentally friendly place. Offshore wind turbines generate much of the city’s electricity. Bicycle paths are three lanes wide on busy streets. The paths are big enough for the 43 percent of Copenhageners who regularly bike to work or school. A new train line opening this year will put most residents within half a mile of a train station. That’ll reduce the need to drive.

To cut down on trash, all apartment buildings now have eight different recycling bins. This helps residents recycle as much as possible. Nonrecyclable garbage goes to a high-tech incinerator. There, it’s burned to generate heat for buildings.

All these changes are part of Copenhagen’s ambitious plan to become carbon neutral: By 2025, the city intends to generate enough clean, renewable energy to offset the carbon it releases into the atmosphere from use of fossil fuels and other polluting energy sources. It aims to create so much renewable energy that it can export some of it and reduce the carbon emissions those other places would have generated. (Denmark is one of 19 countries that recently pledged to become carbon neutral by 2050.)   

Here’s why Copenhagen’s push for carbon neutrality matters to the rest of us: Half the people on Earth live in cities, and the vast share of the planet-warming gases such as carbon dioxide that scientists say cause climate change come from cities—from automobile tailpipes, power plants that supply electricity, and landfills. Cities are both a huge part of the problem and a potential source of solutions.

All these changes are part of Copenhagen’s bold plan to become carbon neutral. By 2025, the city aims to generate enough clean, renewable energy to offset the carbon it releases into the atmosphere. That carbon comes from its use of fossil fuels and other polluting energy sources. The city also expects to create so much renewable energy that it can export some of it. This will help reduce the carbon emissions those other places would have generated. Denmark is one of 19 countries that recently pledged to become carbon neutral by 2050.

Copenhagen’s push for carbon neutrality should matter to the rest of us. Half the people on Earth live in cities. A large share of the planet-warming gases that scientists say cause climate change stems from cities. Carbon dioxide is only one of these gases. These gases come from automobile tailpipes, power plants that supply electricity, and landfills. Cities are both a huge part of the problem and a potential source of solutions.

The experience of Copenhagen, home to 624,000 people, shows what’s possible—and where the challenges lie—for other urban governments hoping to take action against climate change.

Cities “can change the way we behave, the way we are living, and go more green,” says Copenhagen’s mayor, Frank Jensen. His city has some advantages in its quest to be carbon neutral: It’s small; it’s relatively wealthy, with a per capita income of more than $70,000 (compared with about $36,000 in New York City); and its people care a lot about climate change.

Copenhagen has already slashed its emissions by 42 percent from 2005 levels, mainly by moving away from fossil fuels to generate heat and electricity. But politics is making it hard to go further. That is one of the challenges a city faces when trying to tackle such a huge problem on its own. A municipal government can only do so much when it doesn’t have the full support of those who run the country.

Copenhagen is home to 624,000 people. Its experience shows what’s possible for other urban governments hoping to take action against climate change. It also shows where the challenges lie.

Cities “can change the way we behave, the way we are living, and go more green,” says Copenhagen’s mayor, Frank Jensen. His city has some advantages in its quest to be carbon neutral. For starters, it’s small. It’s also relatively wealthy. The city has a per capita income of more than $70,000, compared with about $36,000 in New York City. And its people care a lot about climate change.

Copenhagen has already cut its emissions by 42 percent from 2005 levels. That’s mainly a result of the city moving away from fossil fuels to generate heat and electricity. But politics is making it hard to go further. That is one of the challenges a city faces when trying to tackle such a huge problem on its own. A municipal government can only do so much when it doesn’t have the full support of those who run the country.

Mayor Jensen, a left-of-center Social Democrat, for instance, has failed to persuade the national government, led by a center-right party, to impose restrictions on diesel vehicles in the capital. Transportation accounts for a third of the city’s carbon footprint; it’s the largest single sector, and it’s growing.

“A lot of people living in the suburbs still have diesel cars,” Jensen says. “It’s a political challenge. It’s not a technological challenge.”

And so, Copenhagen’s goal of becoming carbon neutral faces a hurdle that is common around the world: a divide between the interests of people who live in cities and those who live outside them.

But Jensen is still optimistic about what he calls the city’s “green transformation.” Residents have embraced biking, which has surged in popularity. Even on wet, wintry days, bike lanes—elevated above the car lanes so they feel safer—are packed. And Copenhagen is changing the nature of trash. Every day, 300 truckloads of garbage are fed into its recently opened $660 million incinerator. Instead of going to a landfill, the waste is burned, and the heat is funneled through a vast network of pipes to warm the city’s buildings in the winter. High-tech scrubbers remove most chemical pollutants before releasing steam into the air.

For instance, a center-right party currently leads the national government. But Mayor Jensen is a left-of-center Social Democrat. And he’s failed to persuade the national government to put restrictions on diesel vehicles in the capital. Transportation accounts for a third of the city’s carbon footprint. It’s the largest single sector, and it’s growing.

“A lot of people living in the suburbs still have diesel cars,” Jensen says. “It’s a political challenge. It’s not a technological challenge.”

And so, Copenhagen’s goal of becoming carbon neutral faces a hurdle that is common around the world. There’s a divide between the interests of people who live in cities and those who live outside them.

But Jensen is still optimistic about what he calls the city’s “green transformation.” Consider Copenhagen’s recently opened $660 million incinerator. Every day, 300 truckloads of garbage are fed into it. Instead of going to a landfill, the trash is burned. That heat is then funneled through a vast network of pipes to warm the city’s buildings in the winter. High-tech scrubbers remove most chemical pollutants before releasing steam into the air.

Residents have embraced biking, which has surged in popularity. The city’s bike lanes are elevated above the car lanes so they feel safer. Even on wet, wintry days, the bike lanes are packed.

In addition to trying to prevent the worst effects of global warming, Copenhagen is preparing itself for the inevitable impact of climate change too. The rains are more intense, and the sea is rising. Copenhagen sits on the coast of the Baltic Sea. In the most vulnerable, low-lying neighborhoods, the city is creating new parks and ponds for water to collect before it can drain out. There are new dikes by the harbor and a proposal to build a new island in the northeast to block storm surges.

Many Danes welcome the city’s efforts. A 2018 survey by Concito, a Danish environmental think tank, found that addressing climate change was a top issue for Danish voters. Slightly more than half of those polled said they would need to change their way of life to tackle global warming.

Politically speaking, public unease about climate change may be the strongest wind in the mayor’s sails.

“People are honestly concerned about it,” says Klaus Bondam, a former politician and now head of a bicyclists’ group. “You are an extremely tone-deaf politician if you don’t hear that.”

Mariam Hleihel, a medical student from Copenhagen, is one of those who are worried. She says she supports the city’s carbon-neutral goal.

“If we don’t do anything about it now,” she says, “the consequences could be irreversible.”

Trying to prevent the worst effects of global warming is not Copenhagen’s only goal. The city is preparing itself for the inevitable impact of climate change too. The rains are more intense, and the sea is rising. Copenhagen sits on the coast of the Baltic Sea. In the most vulnerable, low-lying neighborhoods, the city is creating new parks and ponds for water to collect before it can drain out. There are new dikes by the harbor and a proposal to build a new island in the northeast to block storm surges.

Many Danes welcome the city’s efforts. A 2018 survey by Concito, a Danish environmental think tank, found that addressing climate change was a top issue for Danish voters. Slightly more than half of those polled said they would need to change their way of life to tackle global warming.

Politically speaking, public unease about climate change may be the strongest wind in the mayor’s sails.

“People are honestly concerned about it,” says Klaus Bondam, a former politician and now head of a bicyclists’ group. “You are an extremely tone-deaf politician if you don’t hear that.”

Mariam Hleihel, a medical student from Copenhagen, is one of those who are worried. She says she supports the city’s carbon-neutral goal.

“If we don’t do anything about it now,” she says, “the consequences could be irreversible.”

With reporting by Somini Sengupta of The Times.

With reporting by Somini Sengupta of The Times.