Abstract

In this paper the main terrestrial ecosystem processes and related feedbacks with the climate system are reviewed and placed in a conceptual framework, used to explore the nature of potential bio geophysical feedbacks at the regional scale prior to executing complex and extensive numerical simulation of the coupled processes. We illustrate the framework for a limited number of regions where significant changes in climate and/or land use are expected. Where possible and appropriate, the quantitative effects of the feedbacks are presented, accompanied with a discussion of the drivers of these results. In Europe, under moisture-limited evapotranspiration conditions, heat waves are potentially amplified by a positive soil moisture-temperature feedback. Future warming and precipitation reduction in the Amazon can be amplified by forest dieback, pointing at a positive soil moistureprecipitation feedback. In India, irrigation may exert a positive soil moisture-precipitation feedback al local and regional scale, while a negative feedback occurs at larger spatial scales. The framework is designed to diagnose possible feedback loops that are worth exploring in further detail by dedicated (model) studies. Being a conceptual framework, complex Biogeophysical processes necessarily are simplified in straightforward process-response relationships. In some of the feedback loops explored, socio-economic dimensions need to be considered, particularly when these affect human decisions on land-use and land-cover change (LULCC). The framework can be used to design the necessary integration of Earth System (ES) and Integrated Assessment (IA) modeling systems.

Keywords: Feedbacks; Land-use change; Climate; Irrigation; Drought; Terrestrial ecosystems