World Cities Day: How urban centers are tackling climate change
The number of people living in cities is expected to balloon in the next few decades, adding to pressures on metropolises working to curb their carbon footprint. So how are they responding?
The challenge of growing sustainably
Cities guzzle more than two-thirds of the world's energy and are responsible for 70% of carbon emissions, according to the UN. They're also home to more than half of the people on the planet. With urban populations only expected to get bigger, how these centers deal with water, pollution, waste, transport and energy will be crucial for tackling climate change.
Copenhagen: Committing to climate neutrality
Copenhagen aims to become the world's first carbon-neutral city by 2025. To get there, the Danish capital wants 75% of all trips to be done on foot, by bike, or by public transport. It's hiked the price of car parking and invested in hundreds of kilometers of roads just for bicycles. The city's district heating system — serving 99% of the buildings — is also switching to sustainable biomass.
Bogota: Mobility for millions
The Colombian capital's bus rapid transit system has brought down CO2 emissions and improved air quality since it was launched in 2000, UN data shows. Bogota's TransMilenio network moves 2.4 million passengers a day and covers 85% of the city. The government also plans to open a metro in 2022 and replace diesel buses with hybrid and electric models by 2024.
Johannesburg: Farming in the city
Africa has the fastest urban growth in the world, adding to climate-related challenges such as food and water insecurity. In Johannesburg, South Africa, people like Lethabo Madela, 30, have started urban farms to grow herbs, vegetables and crops to feed their communities. Officials told Reuters there were 300 such farms in the city of 4.4 million — on rooftops, backyards and empty lots.
Singapore: Green spaces
Beyond providing food, gardens can also help cool cities down, absorb CO2 and prevent flooding. Business hub Singapore is known for its impressive network of green areas and parks, including its iconic Gardens by the Bay. All new buildings in the densely populated city-state must have some form of vegetation, such as hanging gardens or a green roof.
Oslo: Focus on air quality
Norway's capital wants to tackle air pollution by making all cars in the city emission-free by 2030. Oslo, home to some 690,000 people, currently has the highest number of electric vehicles per capita in the world. Drivers get perks like tax credits, access to bus lanes, and free travel on toll roads. During periods of high pollution, the city can also temporarily ban diesel cars from the center.
Seoul: Dealing with trash
Seoul has managed to reduce waste dramatically since the 1990s by introducing a "pay-as-you-throw" system. The densely populated South Korean city recycles 95% of its food waste, for example, with automated bins that weigh scraps and charge residents for what they discard using scannable ID cards. The food waste is then turned into compost, animal feed, or biofuel.
Rotterdam: Water and rising tides
Rotterdam is vulnerable to climate threats such as rising tides because most of the city is below sea level. In order to protect itself from flooding, the Dutch port has built rooftop gardens to absorb runoff, "water plazas" to catch rainwater and parking garages designed to serve as reservoirs. It's also building floating structures — including this dairy farm — to withstand encroaching waters.
Reykjavik: 100% renewable energy
Iceland can produce renewable energy fairly cheaply thanks to its abundance of hydro and geothermal resources. The capital Reykjavik was the first European city to be able to rely entirely on clean power for its electricity, as well to heat homes and swimming pools. Fossil fuels are still used in transport and fisheries, but the city is hoping to phase those emissions out by 2040.
Vancouver: Building green
Buildings are a major source of emissions in cities because of the power they use for lighting, cooling and heating. Vancouver aims to make all new buildings carbon neutral by 2030, and to retrofit old buildings by 2050. One example: The Vancouver Convention Centre (above) has a massive green roof with 400,000 plants that serves as insulation. It also uses seawater for heating and cooling.