Critical zone: an emerging research area for sustainability

Abstract

In the era of Anthropocene, characterized by a dramatic increase in anthropogenic pressure, global changes are challenging the capacity of planet Earth to sustain the development of human societies in the long term. In the past two decades, this concern has fostered worldwide efforts to develop integrated studies of the ‘critical zone’ (CZ), the outer skin of the Earth, extending from the canopy top to the bottom of the aquifer, hosting the continental biosphere and providing basic human needs such as water, food, energy and ecosystem services1. Environmental processes within the CZ, such as energy and mass exchange, formation of soil, streamflow and evolution of landscape are critical to sustain biodiversity as well as humanity2,3. However, with rapid socio-economic development, the CZ is subjected to increasing stress from anthropogenic forcings such as the growth in human and livestock populations, increase in land use, global environmental changes, and expanding consumption patterns4.