Water, it's the very stuff of life, and a high-resolution analysis of the most water-stressed places on Earth reveals anew a stark reality. The Middle East and north Africa (Mena), currently in the middle of a historic wave of unrest, is by far the worst affected region.

Of the 16 nations suffering extreme water stress, according to risk analysts Maplecroft, every single one is in the Mena region. Bahrain tops the list of those using far more water than they sustainably receive. Other crisis-hit countries, including Libya, Yemen, Egypt and Tunisia, are not far behind. Syria tops the next category: high stress. (The full top 20 is in a table below, with a bit on the methodology).

The obvious question is to what extent this severe lack of water underlies the troubles affecting these nations? The obvious response is that only a fool would wade into political and historical waters so deep and try to divine the role of a single factor, amid poverty, unemployment, repression and more.

But reassured by a middle east expert here at the Guardian that water is indeed a major underlying issue in many Mena nations, and John Vidal's article from February, I'm going to dip my toe in as far as following the chain of events that starts with scarce water. Why? Because it powerfully demonstrates how the world's biggest environmental problems link together with profound effect.

First, the Mena region has seen rapid and ongoing population growth, from 127m in 1970 to 305m in 2005. That's a lot more people to feed, and to grow food you need water. But there isn't enough water any more.

That problem was solved by simply throwing money at it: many of the Mena states are rich in oil. Water could be produced by desalination, virtually non-existent in 1970, or, more commonly, food could be bought in from wetter places, importing water in effect.

But when oil and food prices rise, the money-throwing solution becomes harder to sustain. And food prices in particular have certainly been a contributing factor to the so-called Arab spring.

The next solution is to cut out the middle men and buy or lease land in wetter places in order to grow food for export back to the dry Mena countries. Saudi Arabia has done so in Ethiopia, and Qatar in Kenya. Along with other countries including China and South Korea, the Mena countries are leading the "land grab" to alleviate their water woes.

It's a compelling, sweeping (and simplistic?) narrative. It encompasses water, population, food, energy, land grabs and civil unrest. It could, I think, be the start of the first large scale example of the "perfect storm" predicted by the UK's chief scientific advisor, Professor John Beddington, and 20 years sooner than he foretold.

But more than anything, as we nervously watch the Middle East, it shows how environmental problems in one region send waves around our globalised world.

Top 20 water stressed nations Country Water Stress 2011 category Water Stress 2011 rank Bahrain Extreme 1 Qatar Extreme 2 Kuwait Extreme 3 Saudi Arabia Extreme 4 Libya Extreme 5 Western Sahara Extreme 6 Yemen Extreme 7 Israel Extreme 8 Egypt Extreme 9 Djibouti Extreme 10 Jordan Extreme 11 Morocco Extreme 12 Algeria Extreme 13 Oman Extreme 14 Tunisia Extreme 15 Malta Extreme 16 Syria High 17 Mauritania High 18 United Arab Emirates High 19

Methodology: Maplecroft give this definition of their water stress index:

The Water Stress Index evaluates the ratio of total water use (sum of domestic, industrial and agricultural demand) to renewable water supply, which is the available local run off (precipitation less evaporation) as delivered through streams, rivers and shallow groundwater. It does not include access to deep subterranean aquifers of water accumulated over centuries and millennia [as these are not renewable].

It also excludes fresh water produced by desalination, as almost all of this is powered by oil and is hence not renewable.

All the nations in the extreme category use more water than they naturally receive, which in some cases is virtually none.