Greta Jimenez
Cities are major contributors to climate change and air pollution, which is one of the world's largest health and environmental problems. Urban areas account for less than 2% of the Earth's surface, yet they consume 78% of the world's energy and produce over 60% of greenhouse gas emissions. While it is challenging to track emissions, researchers have found that the 100 highest-emitting cities account for 18-20% of the global carbon footprint. Wealth and population size are significant factors, with the cities with the largest per-person footprints being exceptionally wealthy. The burning of fossil fuels, which is still the primary source of electricity, is a major contributor to CO2 emissions and global warming. The transition to renewable energy sources is crucial, as they emit little to no greenhouse gases or pollutants and are becoming increasingly affordable.
| Characteristics | Values |
|---|---|
| Number of cities analysed for carbon footprint | 13,000 |
| Residents of these cities accounting for 20% of humanity's carbon footprint | 100 |
| Residents of these cities accounting for 18% of the global carbon footprint | 100 highest-emitting cities |
| Cities with the largest per-person footprint | Hong Kong, Abu Dhabi, Dubai, Singapore, and Hulun Buir |
| Cities with the largest carbon footprint | Seoul, Guangzhou, New York, Hong Kong, and Los Angeles |
| Wealthier people's carbon footprint | Higher |
| Cities' contribution to world's carbon footprint | 60%+ of greenhouse gas emissions |
| Cities' consumption of world's energy | 78% |
| Cities' land coverage | <2% of Earth's surface |
| Urban areas population projection by 2050 | 2.5 billion people |
| Percentage of the above in cities in Asia and Africa | 90% |
| Percentage of children breathing toxic air daily | 93% |
| Number of children breathing toxic air | 1.8 billion |
| Number of people living in counties that received an F for ozone or particle pollution in "State of the Air" 2025 | 156 million |
| Number of people living in counties that got an F for all three air pollution measures in "State of the Air" 2025 | 42 million |
| Total emissions in 2022 | 6,343.2 Million Metric Tons of CO₂ |
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What You'll Learn
Wealthier people, larger carbon footprint
Cities are major contributors to climate change. Urban areas consume 78% of the world's energy and produce over 60% of greenhouse gas emissions, yet they only account for less than 2% of the Earth's surface. The burning of fossil fuels for electricity generation is a significant contributor to this, with about 29% of electricity currently coming from renewable sources.
The correlation between wealth and carbon emissions is evident when examining the carbon footprints of cities. The cities with the largest per-person footprints tend to be exceptionally wealthy, including Hong Kong, Abu Dhabi, Dubai, Singapore, and Hulun Buir. The emissions of these cities exceed 150 million tons, despite having populations of fewer than 20 million people.
The impact of wealth on carbon emissions is further highlighted when comparing households within the same country. In the United States, the highest-earning 10% of households were linked to 40% of total national emissions in 2019. This disparity is also observed in other countries, with the top 10% of earners in Europe and East Asia releasing 29 tons and 39 tons of carbon dioxide per person annually, respectively.
The choices and consumption patterns of individuals play a significant role in their carbon footprints. Wealthier people generally consume more goods, live and work in larger buildings, travel more widely, and eat more meat, all of which contribute to a higher carbon footprint. Additionally, investments and the industries in which people work can also significantly impact their carbon footprint.
Addressing the carbon emissions of the wealthy is crucial in the fight against climate change. While individual action alone is not sufficient, it is important to recognize that the choices people make influence their carbon footprints. Policies that incentivize decarbonization, such as taxing investments based on their carbon intensity, can encourage individuals with the most economic power to reduce their carbon footprint.
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Cities with the largest carbon footprints
A study by the Norwegian University of Science and Technology found that emissions are highly concentrated in a small number of crowded, high-income cities and affluent suburbs. The study, which analysed the carbon footprints of 13,000 cities, found that the 100 highest-emitting cities accounted for 18% of the global carbon footprint.
According to the research, Seoul in South Korea has the largest carbon footprint, followed by Guangzhou in China, and New York City. Other cities that featured in the top 20 include Los Angeles, Singapore, Chicago, London, and Dubai. These cities tend to be exceptionally wealthy, with emissions exceeding 150 million tons, despite having relatively small populations of fewer than 20 million people.
The high carbon footprint of these cities is often attributed to factors such as the availability of renewable energy sources, the quality of buildings, the dietary patterns of residents, and transportation options. For example, New York City continues to struggle with air pollution due to fossil fuels released from motor vehicles, factories, and other sources, despite efforts to reduce greenhouse gas emissions. Similarly, Guangzhou, the second-largest carbon emitter, faces serious public health concerns due to air pollution.
To combat these issues, cities have started implementing various measures to reduce their carbon footprint and improve air quality. For instance, Seoul has begun using drones to crack down on illegal incineration and has implemented fines and bans on some diesel-powered vehicles. New York City's Mayor Bill de Blasio has also pledged to uphold the goals of the Paris Agreement, aiming to reduce greenhouse gas emissions and achieve zero waste by 2030.
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Energy production and industry
Energy production and industrial processes are major contributors to pollution in cities. The burning of fossil fuels for energy production is a significant source of greenhouse gas emissions, particularly carbon dioxide (CO2). In 2023, US net electricity generation from utility-scale electric power plants resulted in about 1.53 billion metric tons of CO2 emissions. The generation of electricity is responsible for a large proportion of energy-related emissions, with about 60% of electricity still being produced by burning fossil fuels. Worldwide emissions of CO2 from burning fossil fuels total approximately 34 billion tons per year, with coal, oil, and gas being the main contributors.
The industrial sector is another major source of pollution. Greenhouse gas emissions from industry primarily arise from burning fossil fuels for energy and specific chemical reactions necessary for producing goods from raw materials. Industrial emissions are the third-largest source of direct emissions. When indirect emissions from electricity use are included, the industrial sector's emissions increase substantially. Certain industrial processes, such as iron and steel production, have high emissions intensity, but efforts to adopt more efficient technologies have led to reductions in direct emissions and emissions intensity.
The manufacturing sector, a subset of the industrial sector, emits CO2 and other greenhouse gases by burning fossil fuels and through industrial processes. Some manufacturing processes use fossil fuels as raw materials, and emissions from these energy feedstocks are included in industrial process emissions estimates. In 2021, the United States emitted approximately 6.4 billion metric tons of greenhouse gases, with nearly 80% being CO2.
To address pollution from energy production and industry, there is a growing focus on decarbonizing the electricity sector and promoting renewable energy sources. Cleaner sources of energy, such as wind and solar, are gaining ground and now account for about 29% of electricity generation. These sources emit little to no greenhouse gases or pollutants and are the most affordable power option today. Additionally, initiatives like bike-sharing programs and encouraging walking and cycling aim to reduce air pollution and greenhouse gas emissions associated with transportation in urban areas.
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Transportation and traffic congestion
Traffic congestion increases fuel consumption, leading to higher carbon dioxide emissions and outdoor air pollution. Additionally, congestion increases exposure time for passengers, further exacerbating the health impacts. Studies have found that traffic congestion aggravates air pollution and health risks in urban areas, with higher pollutant concentrations observed during peak hours due to frequent low and idle speeds.
Initiatives to reduce traffic congestion and encourage alternative modes of transportation can significantly improve air quality. For example, the bike-sharing scheme in Hangzhou, China, has not only alleviated traffic congestion but also drastically improved air quality. Similarly, congestion charging zones in London and Stockholm have been predicted to result in health benefits and reduced traffic-related deaths by decreasing the number of vehicles entering congested areas.
Addressing transportation and traffic congestion is crucial in the transition towards more sustainable and resilient cities. With urban areas consuming a significant proportion of the world's energy and producing a large share of greenhouse gas emissions, promoting active transportation options and reducing vehicle emissions can have a substantial impact on mitigating climate change and improving public health.
To achieve this, cities can implement a range of measures such as improving public transport systems, investing in cycling and pedestrian infrastructure, and encouraging the adoption of electric vehicles. Policy interventions like congestion charging and emissions regulations can also play a vital role in reducing traffic congestion and its associated environmental and health impacts.
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Fossil fuels and renewable energy sources
Fossil fuels are the dirtiest and most dangerous sources of energy, contributing to air pollution and climate change. The burning of fossil fuels increases CO2 emissions, causing global warming. In 2018, air pollution from fossil fuels caused $2.9 trillion in health and economic costs, approximately $8 billion per day. According to the World Health Organization (WHO), 93% of children worldwide breathe toxic air daily, with 1.8 billion at serious risk due to the air's pollution level.
Fossil fuels still account for over 80% of global energy production, but renewable energy sources are gaining traction. About 29% of electricity currently comes from renewable sources such as wind, solar, water, waste, and geothermal heat, which emit little to no greenhouse gases or pollutants. Renewable energy technologies are becoming more affordable and efficient, with costs declining over time.
Cities play a significant role in climate change, consuming 78% of the world's energy and producing over 60% of greenhouse gas emissions, despite occupying less than 2% of the Earth's surface. Wealthier cities tend to have larger carbon footprints due to higher consumption, larger built environments, increased travel, and dietary patterns that include more meat. The top five cities with the largest per-person carbon footprints are Hong Kong, Abu Dhabi, Dubai, Singapore, and Hulun Buir.
To reduce pollution and climate change, cities must transition from fossil fuels to renewable energy sources. This transition will also create more jobs in the energy sector, with an estimated net gain of 9 million jobs by 2030. Additionally, renewable energy facilities can be constructed more rapidly than fossil fuel plants, and advancements in battery energy storage systems can help integrate more renewable energy into electric grids.
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Frequently asked questions
Cities are major contributors to climate change. Urban areas consume 78% of the world's energy and produce over 60% of greenhouse gas emissions, despite occupying less than 2% of the Earth's surface. Wealth generally correlates with a higher carbon footprint, as wealthy people tend to consume more goods, live and work in larger buildings, travel widely, and eat more meat.
The cities with the largest carbon footprints in the world are Seoul, Guangzhou, New York, Hong Kong, and Los Angeles. However, when adjusted for population, the highest per-person footprint cities are Hong Kong, Abu Dhabi, Dubai, Singapore, and Hulun Buir.
Greenhouse gas emissions are often measured in carbon dioxide (CO2) equivalent. To convert emissions of a gas into CO2 equivalent, its emissions are multiplied by the gas's Global Warming Potential (GWP). The GWP accounts for the fact that many gases are more effective at warming the Earth than CO2 per unit of mass. For reference, a million metric tons of CO2 are roughly the same mass as 1 million small cars.
Air pollution is one of the world's largest health and environmental problems. It is a risk factor for many leading causes of death, including heart disease, stroke, lower respiratory infections, lung cancer, diabetes, and chronic obstructive pulmonary disease (COPD). Ozone and particle pollution are linked to an increased risk of premature birth and lower birth weight in newborns. Air pollution can also trigger asthma attacks and harm lung development in children.
