BEIJING, April 11 (Xinhua) -- Global urban expansion has been continuously accelerating since 2000, according to a recent research article published in the journal Science Bulletin. The research, conducted by teams from the Institute of Geographic Sciences and Natural Resources Research of the Chinese Academy of Sciences, Northeast Agricultural University and Fujian Normal University, showed that the global urban land area expanded from 239,000 square km in 2000 to 519,800 square km in 2020. Using big data obtained through satellites, the researchers developed 30-meter-resolution data products of global urban expansion, urban impervious surfaces, green spaces and water areas for every five years from 2000 to 2020.