The role of urbanisation in increasing atmospheric CO2 concentrations: Think globally, act locally

Abstract

Deforestation for economic development and urbanisation or urban sprawl as a result of human population growth is a common feature of land-use change and is an important source of increased atmospheric CO2. At the global level, carbon emissions from burning fossil fuels are two to three times higher than carbon sequestration by land systems, mainly forests and woody vegetation. Balancing the global carbon budget would require many approaches at local scales. We used remote sensing data to analyse land-use changes in north-central Indiana in the Midwestern USA between 1940 and 1998. The area is characterised by increases in forest and urban land and decreases in agricultural land and grassland. The rate of urban sprawl was much greater than that of forest expansion, and the increase in CO2 emissions over time was much greater than CO2 sequestration in the region. The overall effects of the land-use change have led to the region becoming an increasing source of CO2 in the past half-century. It is necessary to promote afforestation of marginal agricultural land, adopt improved soil/crop management practices, and use renewable energy in the region. If all these potential actions are taken, the gap between CO2 emissions and carbon sequestration could be narrowed from 214 to 71 t C/km2/y.