For several decades now, urban environments, cities, have been one of the key concepts when it comes to the international sustainability agenda.

And it is not surprising that cities are becoming key players in the management of the challenges associated with the social, environmental, economic and good governance aspects of our societies. Half of humanity today - 3.5 billion people - live in them, and the data on the growth of the urban population at a global level is surprising. The United Nations indicates that almost 70% of the world's population will be urban by 2050, with an exponential growth forecast that does not seem to be slowing down.

Cities, precisely as a result of these demographic changes, are at the center of major challenges to sustainability on our planet. They are under pressure from urban sprawl, the consumption of natural resources and energy, new lifestyles, waste management and climate change, among many other aspects.

Cities are, without a doubt, important wheels of the great gear that means sustainability, and they have an essential role in achieving the goals of the 2030 Agenda. That is why the United Nations chose cities as one of the Sustainable Development Goals. Goal 11, "make cities and human settlements inclusive, safe, resilient and sustainable" lays the foundation for achieving the fulfillment of many other global sustainability goals. We are not only talking about environmental goals, but their link with the achievement of social or human development objectives, such as equality, poverty eradication or the reduction of inequalities, among other global challenges, is, if possible, even more evident. After all, we must not forget that urban areas account for 70% of the world's gross domestic product.

Beyond the SDGs, the United Nations established the New Urban Agenda at the end of 2016 at Habitat III, the world conference on sustainable urbanization. This document is intended to be the guide for States in terms of making cities more friendly, sustainable, safe, resilient, inclusive, compact and healthy environments. It again recognizes the global challenges and how cities can and should contribute to addressing them.

On the other hand, the recognition of both the effort made and the potential of the actions to be carried out by cities, as well as by other agents, is one of the key results of the Paris Agreement. It is estimated that, by 2030, 75% of energy consumption and nearly 75% of global greenhouse gas emissions will originate in urban centers, so it is logical that the Agreement recognizes their important role in achieving the established emissions targets.

But what do we mean when we talk about sustainable cities? The World Business Council for Sustainable Development (WBCSD), of which Forética is the representative in Spain, defines a sustainable city in a very simple way. To speak of sustainable cities is to speak of resilient cities, capable of adapting to economic, social or environmental changes, while maintaining a decent quality of life for their inhabitants. It also implies that the planning and development of the city occurs with these criteria in mind, allowing inhabitants to maintain a sustainable lifestyle.

Undoubtedly, it has never been more important than now to have a city model that takes into account this new approach. A model of a more compact city, with fewer trips and easier to supply. A city that fights against climate change, making a transition towards more efficient and safer transport models and opting for a reduction in the use of motorized vehicles. Making cities healthy centers, with greater access to green areas and public spaces, favoring the physical and psychological health of their inhabitants and bringing nature closer to the cities. Thanks to these and many other actions, we will also make cities more inclusive and egalitarian centers that can also contribute to education and the end of poverty.

Collaboration, an indispensable element for more sustainable cities

In order to change the way cities are planned and thought about, collaboration and international cooperation between governments, the private sector, civil society (NGOs, universities) and other stakeholders will be essential to achieve medium- and long-term objectives.

National and especially local governments are already working from this new perspective of cities, with a strong focus on mitigation and adaptation to the effects of climate change, waste management and improved mobility, among many other issues. Networks such as ICLEI (Local Governments for Sustainability), UCLG (the World Network of Cities and Local and Regional Governments), C40 (the Cities Climate Leadership Group) or Compact of Mayors are a good example of the positioning and progress that many city councils at international level are already implementing.

The business sector undoubtedly has a key position in contributing to more sustainable cities. It has the capacity to implement actions that not only facilitate the creation of more sustainable cities, but also take advantage of opportunities and synergies with local environments. From the consideration of its social and environmental impact in the surroundings of its operations, the improvement in the efficiency of its processes, the use of technology as a tool that facilitates the creation of smart cities or even favoring the work environment among its workers, promoting healthy living habits or reconciliation measures with multiple benefits.

This is why both business initiatives and public-private partnerships are essential to achieve the objectives of this new urban agenda faster and with better results.

Forética, an association of companies and professionals in the field of corporate social responsibility, has been working for several years from this dual perspective. On the one hand, we have launched the Sustainable Life in Cities Initiative, in which we have the support of Reale Seguros, the Spanish Climate Change Office and the FEMP, and which seeks examples of collaborative projects that companies, together with different stakeholders, are carrying out in Spain under this theme. Examples of social inclusion in cities, communication and public awareness, circular economy or health are just some of the lines of action on which the projects already received are based.

On the other hand, at the end of 2015, we created the Climate Change Cluster, a business meeting point for leadership, knowledge, exchange and dialogue on climate change, formed by 51 companies. During this year, and due to the opportunity that the concept of "sustainable city" means for all types of sectors, we are working around the issue of the impact of climate change in cities. The objective is to learn about international trends in this area and facilitate the exchange of experiences. In addition, we want to give visibility to the projects that companies are already carrying out through a publication that we will present at the Smart City Expo World Congress in Barcelona in November.

Among them, we can highlight projects linked to improving employee mobility, such as those of Endesa, Correos, Enagás or Aena; awareness-raising and sensitization of their customers and society as a whole, such as those of El Corte Inglés, Leroy Merlin or IKEA; biodiversity management, such as those of Solvay or Suez; those that consider the perspective of circular economy or waste management, such as those of Nestlé or Ecoembes; or those linked to the use of technology for the optimization of services, such as those of Indra or Vodafone. These are just some of the solutions that many companies are implementing to respond to the challenges of sustainability in cities.

Partnering and collaborating with other stakeholders makes even more sense in this particular area as the smartest way to contribute to solving urban sustainability challenges. The power of the private sector to bring about change, generate business opportunities and foster the sustainable prosperity of cities around the world is undeniable.

" The future of the planet is at stake in cities," said Nicholas Stern, the author of the famous report on the impact of climate change on the economy, a few years ago. We have the choice to change the type of environment in which we will live in the future. The opportunity to make cities not only more adaptable to change, but also places where it is more attractive and healthier to live, where all stakeholders are involved, where many of the world's most pressing social challenges are solved. Let's take advantage of it.

Published in the Sustainable City magazine (page 21)