The remaining sections of this chapter cover a range of broadFigure 1.1 - United Nations sustainable development – topics. First, we briefly discuss crises related to climate change, 17 goals to transform our world healthcare, and economics. We then define what a smart city is. Expanding on our definition, we then discuss six main points that help us to understand better the different dimensions of the smart and sustainable city. After that, we briefly discuss the difficulties that cities face and set out the main challenges facing cities that want to become sustainable. Climate change, health and economic crisis According to statistics from the United Nations Population Fund, since 2007, more than half the world’s population has been living in cities, and that share is projected to rise to 60Source: https://www.un.org/sustainabledevelopment/ percent by 2030, when around five billion people will be living in urban hubs. However, these areas and locations face seriousThe Sustainable Development Goals are the blueprint for danger because of the climate crisis and climate change. Twoachieving a better and more sustainable future for everyone numbers neatly sum up this danger: cities consume 75 percentaround the world. They address the seventeen global challenges of the world’s energy production and generate 80 percent ofEarth faces, including, for example, poverty, inequality, climate CO emissions. The planet is becoming increasingly urbanized.2 change, environmental degradation, peace, and justice. As a general long-term policy, the UN considers the Sustainable A- The United Nations’ sustainable development goalsDevelopment Goals to be essential for bringing about recovery after the COVID-19 pandemic in a way that “leads to greener, In 2015, the United Nations launched its 17 Goals to Transformmore inclusive economies, and stronger, more resilient Our World, which are also known as the Sustainable societies.”8 Development Goals (SDGs). According to the UN, “The goals are a call for all countries—poor, rich and middle-income alike—toAmong the seventeen goals, SDG 11 squarely focuses on cities take action, and they aim to promote prosperity while protectingand metropolitan areas.9It sets the following objective: “Make the planet.”6 The idea is to “recognize that ending poverty mustcities inclusive, safe, resilient and sustainable.”10Cities are go hand in hand” with strategies that “build economic growthspatial engines of economic growth, contributing about 60 and address a range of social needs including education,percent of global GDP.11However, urban areas also account health, social protection, and job opportunities, while tacklingfor about 70 percent of global carbon emissions and over 60 climate change and environmental protection.” In the UN’spercent of nonrenewable resource use.12“Rapid urbanization view, the time has come for change to be delivered through ais resulting in a growing number of slum dwellers, inadequate profound systemic shift to a more sustainable economy thatand overburdened infrastructure and services (such as works for both people and the planet. As UN Secretary-Generalwaste collection and water and sanitation systems, roads António Guterres puts it, “We need to turn the recovery into aand transport), worsening air pollution and unplanned urban real opportunity to do things right for the future.”7 sprawl.”13 (6) https://www.un.org/sustainabledevelopment/ (accessed on 19 February and 3 June 2021). (7) UN Secretary-General António Guterres. https://www.un.org/sustainabledevelopment/sdgs-framework-for-covid-19-recovery/ (accessed on 19 February 2021). (8) https://www.un.org/sustainabledevelopment/sdgs-framework-for-covid-19-recovery/ (accessed on 19 February and 3 June 2021). (9) https://www.un.org/sustainabledevelopment/cities/ (accessed on 19 February 2021). (10) 1/”Half of humanity – 3.5 billion people – lives in cities today and 5 billion people are projected to live in cities by 2030. 2/ 95 per cent of urban expansion in the next decades will take place in developing world. 3/ 828 million people live in slums today and most of them are found in Eastern and South-Eastern Asia. 4/ The world’s cities occupy just 3 per cent of the Earth’s land, but account for 60-80 per cent of energy consumption and 75 per cent of carbon emissions. 5/ Rapid urbanization is exerting pressure on fresh water supplies, sewage, the living environment, and public health. 6/ Cities account for between 60 and 80 per cent of energy consumption and generate as much as 70per cent of human-induced greenhouse gas emissions. 7/ 90 per cent of urban growth is forecasted to happen in Asia and Africa in the next 30 years. 8/ By 2050, 70 per cent of the world population is predicted to live in urban settlements.” https://www.un.org/sustainabledevelopment/cities/#tab- 2267862e52845f3d178 (accessed on 19 February 2021). (11) GDP is the Gross Domestic Product: the total value of goods and services produced in a country in a year. (12) https://www.un.org/development/desa/undesavoice/more-from-undesa/2020/02/48525.html (accessed on 19 February and 3 June 2021). (13) https://unstats.un.org/sdgs/report/2019/goal-11/ (accessed on 5 July 2021) 31 Quélin and Smadja | HEC PARIS | SMART CITIES | The sustainable program of six leading cities | 2021