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The
Circular
Cities
Barometer

Inside the
world's race to
net zero

If the planet is to achieve net zero carbon emissions, cities are where it will happen first. Cities produce more than 60% of the world's greenhouse gas emissions, according to the United Nations, but they are also laboratories and key actors for conquering climate change.

Using a proprietary algorithm, the Circular Cities Barometer created by Holcim and Bloomberg Media Studios measures how fast 25 global cities are transitioning from a linear economy—taking, making and wasting—to a circular economy of reducing, reusing and recycling.

We scored cities on a dozen circularity indicators in four categories:

  1. Buildings
  2. Systems
  3. Living
  4. Leadership
collage

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      • Indicators
      • Indicators
      • Indicators
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CATEGORIES

INDICATORS

City
Score
Category
Breakdown
? How much the city's performance in Circular Buildings, Systems, Living and Leadership contributed to its overall score.

Methodology

The Circular Cities Barometer scores cities based on the circularity of their buildings, systems, living and leadership.

Circular Buildings

With buildings generating nearly 40% of annual global CO2 emissions, according to the International Energy Agency, circular cities require circular construction.

Energy Efficiency

The intensity of energy use of a city's buildings.

Urban Temperature

How much higher a city's temperatures are compared to surrounding areas

Building Certification

How many of a city's buildings are certified as green.

Circular Systems

The U.S. recycling industry alone processes more than 130 million tons of recyclables each year, according to the Bureau of International Recycling.

Renewable Energy Consumption

How much of a city's energy is sourced from renewables.

Solid Waste Recycling

How much of a city's solid waste is diverted from landfills and incineration.

Water Recycling

How much of a city's wastewater is safely treated.

Circular Living

The amenities of urban life will attract 6.5 billion people - or 68% of the world's population - by 2050, up from the 4 billion who live in cities today, according to the United Nations.

Green Space

How much of a city is covered by trees and greenery.

Transport

How much of a city is within walking distance of public transit.

Sharing Economy

How many bike-, e-bike- and scooter-sharing programs exist in a city.

Circular Leadership

More than 1,000 cities worldwide have committed to reaching net zero by 2050.

The Paris Agreement

Whether a city committed to measures to limit warming to 1.5℃.

Policies and Roadmaps

How many commitments and achievements a city has made in the transition to a circular economy.

Investment

A city's financial incentives to adopt renewable energy for transport and buildings.

Methodology

1. Overview

The Circular Cities Barometer demonstrates how fast 25 global cities are transitioning from a linear economy—taking, making and wasting—to a circular economy of recycling, reducing and repairing.

Each city was scored based on its performance on 12 indicators of circularity, organized within four categories. Indicators and categories were weighted, as described below, to reflect their importance and the quality and quantity of data available.

2. City Selection

The 25 cities were selected from among the nearly 100 cities whose mayors participate in C40, a global network collaborating to address the climate crisis. C40 operates on performance-based requirements that set minimum standards of climate action that must be met for membership. C40 is funded in part by Bloomberg Philanthropies, the charitable organization of Michael R. Bloomberg, founder and majority owner of Bloomberg LP.

Cities were selected so that all global regions were represented, and to ensure that representative data was available.

3. Data Collection

We gathered data from secondary sources that were available through March 2022. For some indicators, a single data point is used, while for others, a tally of several data points was used. Whenever possible, we used a single source of data for each indicator, but some cities required the use of alternative data sources, such as estimates or national figures, noted below.

4. Data Sources

Circular Buildings

Energy Efficiency: Each city was scored on a scale of 1-6, depending on how many of the following commitments it has made:

  • CDP building energy efficiency ratings
  • CDP building performance and ratings
  • CDP new building standards
  • CDP efficiency and/or retrofit projects
  • Global Covenant of Mayors emissions data
  • UN Climate Change Global Climate Action zero-carbon buildings

Urban Temperature: The urban heat island effect—the higher temperatures cities experience versus their less urban surroundings, due partly to the concentration of building materials—was sourced from the Global Urban Heat Island Data Set from the Center for International Earth Science Network (CIESIN) at Columbia University. Dubai's urban heat island effect was estimated due to lack of city-specific data.

Building Certifications: The number of buildings (existing or under construction) that were either Gold or Platinum LEED-certified or BREEAM-certified

Circular Systems

Renewable Energy Consumption: The percentage of annual energy from renewable sources was sourced from REN21, a global renewable energy community of representatives from science, governments, NGOs and industry. Data for Nairobi was sourced from a periodical. Data for Beijing and Wuhan was based on national figures and sourced from a periodical.

Solid Waste Recycling: The percentage of municipal solid waste diverted from landfill or incineration was sourced from the United Nations. Data for Auckland, Lagos, Warsaw and Zurich was based on national figures from the Environmental Performance Index. Data for Beijing, Chicago, Copenhagen, Johannesburg, Montreal, New York, Seattle and Sydney was sourced from periodicals. Data for Wuhan was estimated based on a periodical.

Water Recycling: The percentage of wastewater that's safely treated was sourced from the Urban Environment & Social Inclusion (UESI) Index. Data for Auckland, Lagos, Quezon City, Sydney, Warsaw and Zurich was based on national figures from the Environmental Performance Index. Data for Bogota was sourced from the World Bank. Data for Milan was sourced from digital-water.city. Data for Nairobi was sourced from nairobiwater.co.ke. Data for Seattle was sourced from seattle.gov/utilities/your-services/water/water-system. Data for Wuhan was estimated based on a report from the Asian Development Bank.

Circular Living

Green Space: The percentage of city land defined as tree cover was sourced from the Urban Environment & Social Inclusion (UESI) Index. Data for Auckland was sourced from teara.govt.nz. Data for Dubai was sourced from a periodical. Data for Johannesburg was sourced from datadrivenlaw.org.

Transport: How much of a city is within walking distance of public transit—the definition of Public Transportation Coverage—was sourced from the Urban Environment & Social Inclusion (UESI) Index. Data for Auckland was sourced from at.govt.nz. Data for Dubai and Johannesburg was sourced from periodicals

Sharing Economy: The number of bike-, e-bike- and scooter-sharing programs was sourced from the New Urban Mobility Alliance (NUMO). Data for Auckland was not available because bike sharing had only been piloted there, according to a periodical. Data for Quezon City was sourced from the Asian Development Bank. Data for Beijing, Johannesburg, Montreal, Nairobi and Wuhan was sourced from a periodical. Data for Lagos was estimated based on a periodical.

Circular Leadership

The Paris Agreement: For each city, its alignment was sourced from the CDP (formerly the Carbon Disclosure Project). If CDP ranked the city as an A List City—which means it has publicly disclosed its citywide emissions inventory, set an emissions reduction target and a renewable energy target and published a climate action plan, among other indicators—it scored a 2. If it has committed to limiting warming to 1.5 to 2 degrees Celsius compared to pre-industrial levels, but is not an A List City, it scored a 1. If the city has not committed to a warming limit or is precluded from doing so by its national government, it scored a 0.

Policies and Roadmaps: The number of mitigation memberships, commitments or achievements was sourced from the partnership of the CDP (formerly Carbon Disclosure Project) and ICLEI—Local Governments for Sustainability (formerly the International Council for Local Environmental Initiatives). For Beijing, data was sourced from china.org.cn.

Investment: The following fiscal incentives were sourced from REN21, a global renewable energy community of representatives from science, governments, NGOs and industry. If a city provided fiscal incentives for renewable energy for transport, it scored a 1. If it provided fiscal incentives for renewable energy for buildings, it scored a 2. If it provided fiscal incentives for renewable energy for both transport and buildings, it scored a 3.

5. Scoring Process

The data collected for each indicator was normalized around a mean of 0 to make the data “apples to apples.” These normalized figures were added together to get the normalized figure for each category, as well as the normalized figure for overall circularity. The normalized figures were then used to give each city a score between 0 and 100 for each indicator, each category and overall circularity. In the case of a tie, cities are listed in alphabetical order.

6. Weighting Process

The data was weighted based on:

  • The impact a category or indicator has on the circularity of a city
  • The number of cities reporting data for a given indicator
  • The number of cities participating in a given indicator

Coming Soon

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