The need for green and atmospheric water governance

A review of the literature on water governance reveals that most studies focus on blue water governance; while there is some literature on green and atmospheric water, explicit literature on how to govern green and atmospheric water is lacking. Hence, this paper addresses the question: What are the arguments for governing green and atmospheric water? In order to address this question, we have undertaken a scoping analysis of the literature on green and atmospheric water. We conclude that water governance must proactively address green and atmospheric water since: (a) blue water represents only a part of the available fresh water; (b) blue river basins represent only a subset of the wider systemic nature of water; (c) land use change has significant impacts on various water flows, which all may need to be governed; (d) climate variability and change influences blue, green, and atmospheric water availability; (e) an understanding of the socio‐ecological uses of the different colors of water is critical for a more optimal and legitimate governance of water; (f) new water technologies make it increasingly possible to modify the use of green and atmospheric water; and (g) global trade infrastructures pressurize local green water resources. Neglecting the need for explicit governance of green and atmospheric water could create new forms of “water grabbing” that would impact water availability beyond the basin scale

Reviewing the Impact of Land Use and Land-Use Change on Moisture Recycling and Precipitation Patterns

Green water, or plant-available soil moisture, is a substantial subset of terrestrial fresh water. Land use change alters green water dynamics through interactions on the micro-level (i.e. between the soil and vegetation) and on the macro-level (i.e. between the land surface and atmosphere). Ongoing global deforestation, and growing interest in reforestation projects, begs the question whether such large-scale land use changes have major eco-hydrological impacts via the process of terrestrial moisture recycling (TMR). This requires a systematic, mechanistic understanding of green water dynamics in relation to land use change. Hence, this literature review addresses the above question via a scoping review that draws from papers covering empirical observations and simulated approximations on the hydrological effects of land use change from different parts of the world. The results show that some regions are more vulnerable to land use change than others and can affect local as well as distant hydrology of landscapes. Furthermore, we find that many studies focus on the global level or on tropical rainforests, through which we identify a knowledge gap for temperate regions and drylands. We derive analytical tools and directions for further research that can improve understanding of the effects of land use change on moisture recycling patterns in order to minimize unexpected hydrological impacts for nature and society