Sequestering carbon in soils of arid ecosystems

Abstract

AbstractRecent increase in atmospheric concentration of CO2 and decrease in land‐based sink capacity are attributed to numerous anthropogenic activities including increase in severity and extent of soil degradation and desertification. There is a strong link between desertification and global warming with positive feedback of mutual reinforcement. The biophysical process is also driven by social, economic, political, and cultural factors such as overgrazing by local Bedouin population. Soil carbon (C) sequestration, through conversion to a restorative land use and adoption of recommended management practices, is more in cooler than warmer and higher in wetter than drier climates, and larger in clayey than sandy soils. It ranges from 0 to 200 kg C ha−1 y−1 in soils of semi‐arid climate to 200–500 kg ha−1 y−1 in those of sub‐humid climates. The rates may range from negative to a high of 1500 kg ha−1 y−1. In contrast, the rate of SIC sequestration as secondary carbonates are low and range from 1·5 to 15 kg C ha−1 y−1. In addition to proven technologies (e.g., low stocking rate, afforestaion, soil, and water conservation), there are numerous opportunities for using the modern innovations involving nanotechnology, biotechnology, and information technology. Trading of C credits, through Kyoto's CDM or World Bank's BioCarbon Fund and other mechanisms, opens new opportunities for promoting the use of terrestrial sinks. In this regards, desertified ecosystems in Africa/Asia and elsewhere may benefit through C‐sequestration programs because rehabilitation of degraded lands is an urgent matter of global importance. Copyright © 2009 John Wiley & Sons, Ltd.