UNEP’s GRID Arendal web page that “collect[s] and catalogue[s] all graphic products that have been prepared for publications and web-sites from the last 15 years in a wide range of themes related to environment and sustainable development.” It has mainly maps and infographics. Not that many Sankey diagrams, but one I found this one interesting:

It is titled ‘Nigeria and the Freswater Challenge’, originally from a 2005 study by the Stockholm Environment Institute (SEI).

The description says:

Out of the total precipitation reaching Nigeria, it can be separated into green and blue water. Green water (79% of the precipitation) represents the fraction of rainfall that generates soil moisture and which supports terrestrial ecosystems. It is not returned to groundwater and rivers, but will eventually evaporate or transpire through plants. Blue water, on the other hand, represents the fraction (21%) of the precipitation that runs into rivers and aquifers, and that has a potential for withdrawal for societal use. Out of this, the environmental water flow is the amount of water needed to sustain ecosystem services. In the case of Nigeria, there is a huge potential to increase the withdrawal for irrigation and food production to meet current and future needs.

Flows display percentages rather than absolute values. The green water arrow representing 79% is broken down further and reveals the contributions, but only on one segment. Nice idea!

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