The Water Planetary Boundary: Interrogation and Revision

Integrating the Water Planetary Boundary With Water Management From Local to Global Scales

“…Regarding water, which is our focus here, the planetary boundary for freshwater use was originally based on the amount of freshwater that could be withdrawn while maintaining rivers' environmental flow requirements globally (Gerten et al, ; Steffen et al, ). Recently, Gleeson et al (, ) proposed to distinguish six water sub‐boundaries relating to the major stores of freshwater to more holistically represent the various functions of water in maintaining Earth System stability (Table ). Environmental flow requirements are retained in this approach as the surface water sub‐boundary, together with new water planetary sub‐boundaries for frozen water, groundwater, soil moisture, and two sub‐boundaries for different aspects of atmospheric water.…”

“…Environmental flow requirements are retained in this approach as the surface water sub‐boundary, together with new water planetary sub‐boundaries for frozen water, groundwater, soil moisture, and two sub‐boundaries for different aspects of atmospheric water. Gleeson et al (, ) suggested potential control and response variables for these new sub‐boundaries (Table ), but significant work remains to select and evaluate appropriate variables and boundary values. To provide a sound societal relevance for these efforts, it is necessary to first determine whether the water planetary boundary can be meaningfully integrated with existing water management approaches.…”

“…The first step in operationalizing the fair shares approach is defining the safe operating space by determining values for each of the water planetary sub‐boundaries. While recent work has proposed new planetary sub‐boundaries for different stores of water in the Earth System (Gleeson et al, , ), previous efforts to operationalize the planetary boundaries framework using the fair shares approach have all used the control variable and estimated boundary values from Rockström et al () and Steffen et al () (Table S1). In the case of water, this means that the planetary boundary is typically taken as 4,000 km 3 year −1 of consumptive blue water use.…”

Water resilience and human life support - global outlook for the next half century

“…The other is the limitations originating in the origin of the rainfall that feeds the river basin and therefore further threatens the water resource. The large rivers in north-east China are examples of vulnerable rivers in a sink region, with a high proportion of their precipitation originating in upwind terrestrial evaporation in Siberia (Keys et al, 2012) and vulnerable to upwind use change in inner Asia (Gleeson et al, 2019).…”

“…A recent upgrade towards a second generation (Gleeson et al, 2019) was based on considering freshwater core functions in search of a set of sub-boundaries, which are now open for quantification of six sub-boundaries. Human activities in the landscape involve unavoidable water partitioning alteration, which suggests the question of at what stage such alterations are too large to allow Holocene conditions.…”