Changing land uses and greenhouse gas emissions: a case study of an ancient city in India

Abstract

The land-use change is a recognized contributor to the anthropogenic greenhouse gas (GHG) emissions. Rising population has forced conversion of natural land uses to agriculture and human settlements. Varanasi, an ancient city, is experiencing an urban sprawl, which is leading to expansion of city boundary. A large area under forests has already been converted into agriculture. Under increasing load of waste generation, some of these agricultural lands are getting converted into dumping sites. The present study is aimed at assessing the fluxes of CH4 and CO2 from different land uses in Varanasi city. Sites representing land uses under forest, agriculture and landfill were identified in and around Varanasi. Forest acted as the net sink for CO2, whereas agriculture and landfill were the net sources. All three sites, however, acted as net source for CH4. The emission rate was lowest in forest, which is the natural land-use type in the region. The land-use conversion also affected soil properties as reflected by the modification in physical properties and nutrient contents. The study clearly indicates significant GHGs emissions associated with the formation of man-made systems.