There most paramount footprints of the mankind are greenhouse gas emissions and urbanization. Down in the Southern China one can clap eyes on one of the most impressive evidences of urbanization, arguably the largest built-up area in the world Pearl, River Delta Metropolitan Area. Just imagine, 39,3980 square kilometers, more than 120 million population, around 10 settlements, at 3 megacities with more than 10 million people within (Hong Kong, Shenzhen, Guangzhou). Its overall population exceeds the number of citizens in any European country. Once we became capable to develop such vast built-up areas, we also must be sure that we know how to track the changes of built-up areas with high accuracy. Administrative divisions of cities just can't keep up with the explosive pace of urbanization of such mega-megacities. Luckily, remote sensing can once again help to reach our most promising aspiration. Night-lights observations from NOAA Defensive Meteorological Satellite Program allow quantifying the strength of night-lights at a district level.
Moreover, an every single step of the Pearl River Delta Urbanization can be tracked in the recent 25 years (see the snapshot above). This knowledge is extremely valuable and already helps scientists to proxy urban emissions, to support composing demographic statistics, capturing "hotspots" of urban emissions and assessing the electricity consumption. We can further hope that night-lights datasets will support transition of these huge built-up areas to become sustainable.
Source: DMSP/OLS satellite observations 1992-203
Data Description: 0 - No light, 64 - Max intensity Data link: NOAA EOS website