Net-Zero Cities: Local Approaches to a Global Problem

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At the start of every year, I find myself invested in a sustainability topic that reminds me of the progress we’ve made on global issues and offers some confidence in the progress we’ll make by the time New Year’s Eve rolls around again. Last year, I focused on promising developments in the rail industry. This year, I’m watching net-zero cities. 

Falling under a handful of different initiatives and names, including zero-carbon cities and carbon-free cities, the movement refers to the often collaborative effort to decarbonize the world’s urban areas. Cities of all sizes use various shared methods to create individual plans tailored to their needs. 

Though some major cities initially hoped to reach net zero as early as this year, most now plan to do so sometime between 2030 and 2050. That might seem far away, but the projects that will make it possible are happening now. Here are some worth watching. 

Reaching 100 percent renewable energy  

Chicago made headlines earlier this month for hitting a goal it set in 2017: powering all city-owned buildings with renewable energy by 2025. As of the first day of the year, everything from the O’Hare and Midway international airports to fire stations, water treatment plants, and public libraries receive 100 percent of their power from renewables. 

Most of the electricity comes from a new 593-megawatt solar farm south of the city. The rest is supplied by purchasing renewable energy credits. These certificates represent the environmental benefits of renewable energy generation and are sold separately from the electricity itself to help organizations meet their sustainability goals. 

Already, the city’s power purchasing agreement with the local solar farm adds more renewable power to the grid than most similar contracts in the United States — second only to Houston, Grist reports. But Chicago hopes its demand will continue to spur local clean energy development to replace the purchase of renewable energy credits.

The city expects this milestone to reduce its annual carbon emissions by 290,000 metric tons. That’s comparable to taking 62,000 cars off the street. It’s all part of a larger plan to reduce carbon dioxide emissions by 62 percent by 2040 and source all electricity consumed in the city from renewables by 2035. 

Reaching 100 percent renewable energy isn’t new. Aspen, Colorado, first adopted a plan to do so in 2004 and reached its goal a year early in 2014. But Chicago’s almost 2.7 million residents dwarf Aspen’s 6,600. It’s one of the biggest U.S. cities to take on the challenge yet. 

The road to fossil-fuel-free streets 

While they work to electrify municipal vehicle fleets, improve public transport, and increase walkability, cities are also trying to reduce greenhouse gas emissions on public roads. London stirred up a flurry of both support and protests when it first announced its Ultra Low Emission Zone in 2019, as have many other European cities. 

The zone is a congestion-pricing policy designed to improve air quality across the city by requiring high-polluting vehicles to pay a daily fee of £12.50, about $15.50 USD, to drive in select areas. After the policy was enacted, the percentage of vehicles in the city that met emission standards on an average day increased to 96 percent, prompting officials to expand the zone across all of London in 2023.

The Ultra Low Emission Zone helped reduce harmful nitrogen dioxide emissions by 53 percent in the city center and 21 percent in outer neighborhoods, according to the government agency Transport for London. Recently, researchers tracked another benefit: More children are walking, cycling, or using public transport to get to school than before the zone existed. Of the central London children surveyed, 42 percent made the switch from taking a car. Though students weren’t asked why they made the switch and complementary changes like safer bike lanes likely also play a role, it’s a promising development for public and environmental health. 

European cities already host over 300 low-emission zones, and over 500 more are in the works this year, according to research from the advocacy organization Transport and Environment. The trend extends past Europe to cities like Los Angeles, Cape Town, Mexico City, Tokyo and Vancouver. As cities like New York try to implement fees for driving in congested areas to improve air quality and fund public transportation — a policy London has successfully implemented since 2003 — I wouldn’t be surprised to see more major names taking steps toward low-emission zones this year. 

Cleaner construction 

Over half of the people on the planet live in cities, and that number is expected to reach two-thirds by 2050. As cities grow, they build, and the built environment is responsible for almost 40 percent of global carbon emissions. For a net-zero-focused city like Norway’s Oslo, which is also one of the fastest-growing cities in Europe, eliminating greenhouse gas emissions from local construction is crucial. 

Having already established itself as a city to watch with its zero-emission public transport efforts and bold emission reduction goals, in 2023 Oslo joined an initiative from C40 Cities focused on making the construction industry more sustainable. C40 is a coalition of mayors working together to cut their cities’ emissions in half. 

The Norwegian city began encouraging emission-free construction machinery in 2019. Since the city government accounts for a fifth of the local market’s construction contracts by value, industry-wide change happened relatively quickly from there. Now, 77 percent of building sites in Oslo are emission-free, according to C40. A current multi-purpose building renovation project, for example, is expected to produce just 17 tons of carbon thanks to zero-emission equipment. That’s compared to almost 250 tons with conventional equipment. 

Starting this year, zero-emission construction equipment is required for all public projects in Oslo.

London is also a part of the C40 construction initiative and recently implemented a new low-emission zone on construction sites. Called the Non-Road Mobile Machinery Low Emission Zone, it requires building sites to have only zero-emission machinery by 2040. 

Of course, the net-zero city movement isn’t perfect. It’s not particularly organized. Tracking and comparing progress between cities is difficult. There are no set standards for when a city can be declared carbon-free. And some methods of reaching that goal — like carbon offsets, renewable energy credits and low-emission zones — are contentious. 

Despite that, the movement demonstrates how a single city can create local changes with worldwide impacts, just as several cities can come together to do so. It’s a reminder that global collaboration, and progress, come in many different forms.