Valuing the off-site effects of land degradation

The off-site economic impacts of land degradation are likely to be quite significant. Valuation theory and methodologies are far ahead of empirical application, which is greatly restricted by the lack of knowledge about biophysical processes within watersheds and relevant data of economy-environment interactions, especially extrapolation across scales. Most empirical studies have sought to estimate the impacts of hydrological changes and sedimentation. Other issues such as biodiversity and climate change have received less attention. Estimates for the global off-site costs of land degradation have reached hundreds of billions of dollars. Yet, upon closer scrutiny these figures can be easily challenged as they do not meet even minimal standards of scientific credibility.