SDG Goal 11: Make cities and human settlements inclusive, safe, resilient and sustainable
11.3.1 Ratio of land consumption rate to population growth rate and
11.7.1 Average share of the built-up area of cities that is open space for public use for all, by sex, age and persons with disabilities.
For a long time of human history, populations have lived in very sparsely populated rural areas - but if we look at the evolution of population densities over the last few decades, we realize that cities are the new preferred habitat for humans worldwide. Today, half of the world's population lives in cities and, according to current estimates, this figure will rise to two-thirds by the middle of this century. Half of the area for these now almost 6.5 billion people, has yet to be built.
(Figure: Tracking public (green) spaces in Medellin using data from Open Street Map)