Newer categories of interest, sadly, include renewable water resources, major infectious diseases and people trafficking.
Others say the amount of accessible, renewable water for mankind is just 15,000,000bn litres.
Brazil alone (population: 190m) has as much renewable water as the whole of Asia (population: 4 billion).
"Europe and some of the countries with shale potential have significantly less renewable water resources than the U.S.," the report warned.
It is the least irrigated and electrified, yet it uses only 3% of its renewable water, against 52% in South Asia.
This problem is particularly relevant in semi-arid regions, where urban storm runoff is considered a renewable water resource.
The higher the proportion of its renewable water resource that a country uses, the more exposed it is to water stress.
Kuwait, for example, has no internal renewable water resources (FAO 2008 ).
Very minimal rainfall compounded with high evapotranspiration rates in this region causes limited availability of renewable water.
According to the IPCC (2014), climate change in most dry subtropical regions will reduce renewable water resources greatly.
The groundwater in these shallow aquifers is the only renewable water sources for the Arabian Peninsula region (FAO 2008).
