The world’s population is expected to reach 9.7 billion in 2050, according to the United Nations Department of Economic and Social Affairs. Urban areas are already home to 55% of the world’s population and this number is expected to reach 68% by 2050. Rapid and unplanned urbanization, combined with the challenges of climate change, can lead to more polluting weather conditions and greater vulnerability to disasters. and problems related to resource management such as water, raw materials and energy.

To better understand current trends in global urbanization, the European Space Agency (ESA) and the German Aerospace Center (DLR), in collaboration with the Google Earth Engine team, are jointly developing the Global Settlement Footprint, the dataset around the world. More detailed human settlements.

The global settlement footprint consists of a combination of several different products, two of which were publicly launched during the recent United Nations Climate Change Conference (COP26): Impact of Global Settlement 2019 (WSF 2019). Effect of settlement (WSF evolution). These products are built using millions of hours of CPU time with Google Earth Engine, Google’s platform for analyzing geospatial data.

Providing information about global human settlements in unprecedented detail and accuracy, WSF 2019 presents data from the Copernicus Sentinel-1 and Sentinel-2 missions, while the WSF Evolution was created by processing seven million US satellite images acquired between 1985 and 2015. , shows the global growth of human settlements year by year.

This unprecedented compilation of global products related to human settlements has advanced our understanding of urbanization on a global scale.

The imprint of a human settlement in Barcelona. (Photo: DLR/ESA. CC BY-SA 3.0 IGO)

New products of the global settlements footprint will become an advantage for national statistical offices, local authorities, civil society and international organizations involved in the implementation of Sustainable Development Goal 11 of the 2030 Agenda for Sustainable Development and the New Urban Agenda. The WSF dataset has proven to be a key resource for analyzing urbanization in developing countries, where there is often little or no information.

Mattia Marconcini, who leads the global footprint of settlement at the DLR, explains that “knowing where humans live is seen as easy, with accessible web services displaying detailed charts on their platforms. If we start by focusing on low- and middle-income countries, particularly In rural and suburban areas, we immediately see clearly that there is a lack of information about the global scale of human settlements in many parts of the world.This is where the global settlement footprint comes in.

“The evolution of the global settlement footprint allows us to see how our cities have expanded in the past 30 years. The availability of satellite data sets allows us to build a knowledge base about the most pressing requirements to achieve the Sustainable Urban Development Goals and to make informed policy decisions.”

The availability of continuous high-quality data streams and free satellite observations such as those of the European Copernicus Sentinel and Landsat missions, along with the emergence of automated methods for big data processing and data analysis, as well as the democratization of computing costs, said Mark Paganini of the European Space Agency. , provides unprecedented opportunities to efficiently monitor changes and trends in global urban development. The global settlement footprint is a great example of how the data revolution can mobilize for the benefit of all countries and cities, leaving no one behind, and is one of the guiding strands of the 2030 Agenda for Sustainable Development.

The new WSF products have received positive feedback from many users, who have been granted initial access, namely the World Bank, Asian Development Bank, UN-Habitat and International Committee of the Red Cross.

Robert Ndugua, Head of the UN-Habitat Data Division, who heads global urban statistics at UN-Habitat, commented: “The evolution of the impact of global settlements has made it possible to analyze and compute spatial urbanization trends, not only for cities and urban areas, but also at the national and global level. We have to move towards building sustainable cities and human settlements, and that depends on whether we can measure these areas well and predict future growth in all of these cities.I think Earth observation and geospatial technologies provide us with the tools we need to grow in that direction.

Sameh Wahba, Director of Urban Practice, Disaster Risk, Resilience, and Land Management at the World Bank, added, “Data science is widely used to understand and analyze current development trends, key challenges, and future urbanization scenarios in all regions. Our partnership with ESA, DLR and other Organizations in recent years have pushed the boundaries of our knowledge and made data-driven decisions Using the evolution of the global settlement footprint, our team tracks flood risk exposure in developing cities around the world, such as Bangkok in Thailand The data suggests that we are facing a worrying trend: New and unplanned settlements have grown exponentially High-resolution data allows us to work with our partners around the world to determine how this risk is evolving and to identify the drivers of this high-risk urban growth.

The 2019 global settlement footprint can be checked at this link (Earth Observation Center DLR), while the development of the impact of global settlement can be seen on the site this link. (Source: European Space Agency)