From the EU’s Joint Research Center (JRC):
The JRC has launched a new tool with data on all 10,000 urban centres scattered across the globe. It is the largest and most comprehensive database on cities ever published.
With data derived from the JRC’s Global Human Settlement Layer (GHSL), researchers have discovered that the world has become even more urbanised than previously thought.
Populations in urban areas doubled in Africa and grew by 1.1 billion in Asia between 1990 and 2015.
Globally, more than 400 cities have a population between 1 and 5 million. More than 40 cities have 5 to 10 million people, and there are 32 ‘megacities’ with above 10 million inhabitants.
There are some promising signs for the environment: Cities became 25% greener between 2000 and 2015. And although air pollution in urban centres was increasing from 1990, between 2000 and 2015 the trend was reversed.
With every high density area of at least 50,000 inhabitants covered, the city centres database shows growth in population and built-up areas over the past 40 years. Environmental factors tracked include:
- ‘Greenness’: the estimated amount of healthy vegetation in the city centre
- Soil sealing: the covering of the soil surface with materials like concrete and stone, as a result of new buildings, roads and other public and private spaces
- Air pollution: the level of polluting particles such as PM2.5 in the air
- Vicinity to protected areas: the percentage of natural protected space within 30 km distance from the city centre’s border
- Disaster risk-related exposure of population and buildings in low lying areas and on steep slopes.
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