Reconstruction of cropland areas for South Asia from AD 640 to 2016

Much attention was paid to reconstructing historical land use to reveal the impact of anthropogenic activities on the environment. Great significance but relatively weak progress was detected in present reconstructions of historical land use for South Asia. First, we estimated the historical population of South Asia (India, Pakistan, and Bangladesh); then, we calculated its per capita cropland areas for AD 640–1871 when reliable historical archives were available. By multiplying them with the population estimates and combining them with the official land use census, we got the cropland areas of South Asia from AD 640 to 2016. The population of South Asia increased from 58.1 million in AD 640 to 1686.1 million in AD 2016, presenting a slow growth trend pre-1801 and an exponential growth trend post-1801. The cropland area increased from 42.89 Mha in AD 640 to 185.69 Mha in AD 2016, showing a slow growth trend before AD 1801 and an accelerated growth trend from AD 1901 to 1990, followed by a slight decline. The provincial cropland area showed a considerable increase from AD 1901 to 2016. The provinces with the greatest intensification were Bengal of British Raj for AD 1901–1941 and Punjab Province of Pakistan for AD 1950–2016.