Fresh water depletion and contamination: a real problem

When speaking about this blog, several people have questioned why water scarcity is an issue. The overall amount of water on the planet is not going to change any time soon and so why should we be worried about potential water shortages affecting two-thirds of the global population by 2030? 

To answer this, we can look at how water arrived on Earth, and what processes change it now that it's here. 

Water has accumulated on the surface of the Earth over the past 4.6 billion years from various sources: volcanism releasing water vapour into the atmosphere; hydrated minerals inside rocks and the deeper Earth releasing water; and a steady bombardment of extra-terrestrial missiles, some of which are carbonaceous chondrites (undifferentiated stony meteorites) containing water.

The following diagram explains the basic principles of the hydrological cycle. Water evaporates from the surface of the Earth, condensates to form clouds, falls as precipitation back to the Earth where it either infiltrates the land and goes into groundwater supply, or forms rivers and lakes of fresh water which eventually run into the sea.

Human activity interferes with this cycle in a number of ways. Firstly, increasing temperatures due to climate change means water cannot infiltrate the ground as much in arid regions as the ground is harder, increasing surface run off and consequently how much fresh water ends up in the sea instead of groundwater. The increased temperatures will also mean there is less surface water available in rivers and lakes for immediate use due to increased evaporation. Secondly, built up areas also increase the amount of surface run off as water is unable to penetrate hard concrete buildings and roads. Drainage is applied in many agricultural areas to prevent water build up, and this increases run off by 20-30% (Kuchment, 2007).

The quality of the fresh water reserves is also affected by human activity. 70% of fresh water withdrawn from the Earth goes towards agriculture where it is used to irrigate crops that are also sprayed with a wide range of fertilisers and chemicals that are then incorporated into rivers, lakes and the water table, sometimes in significant quantities. On top of this, sewage can leak into groundwater from septic tanks, and is also often deposited into rivers (in developing countries, 80% of sewage is dumped untreated) which can cause them to carry a wide variety of diseases. Lastly, a lot of industrial waste is also discarded into the water supply all over the globe, but more so in developing countries that may have fewer regulations. A UN estimate put this figure at 300-400 mega tonnes annually. A report by the USGS points out there is often interaction between surface and sub-surface flows, which would lead to the transfer of these chemicals between rivers, lakes and aquifers thus polluting all sources of freshwater, not just the one that the pollutants were deposited into.

Groundwater is especially polluted in some developing countries such as India, where high levels of fluoride, arsenic and salinity pose health problems (Kumar & Shah, no date). Future posts will discuss areas like this in more detail, as well as covering means of increasing the fresh water supply for countries located in arid regions.

       Two boys collect water from a leaking pipe, surrounded by 

       polluted and contaminated water in India.

       Photograph: Reuters

Water Wars... a thing of the past, present and future.

I was reading a 16 year old speech by Lester R. Brown from the Stockholm Water Conference in 2000 in which he stated that ‘It is now commonly said that future wars in the Middle East are more likely to be fought over water than over oil.’  Since then The Pacific Institute has compiled a list of conflicts related to water, some of them dating back to 3000BC. It is striking to see how many there have been, ranging from protests leading to violence, to all out military operations. Unerringly it also shows how frequently cutting off water supply to towns, cities and regions has been used as a military offensive tool, most recently in the Syrian civil war.

Water has been called the ‘forgotten cause of conflict in the Middle East.’ Wikileaks revealed cables sent by US ambassador Stephen Seche in 2009 which claimed 14 of Yemen’s 16 aquifers had run dry. He also said ‘70% of unofficial roadblocks stood up by angry citizens are due to water shortages’. In Taiz, the city where major protests played a large part in starting the uprising in Yemen in 2011, piped water flows through the pipes roughly once every 40 days.

Not only has water been used as military tool in the war in Syria, but there is evidence that the severe drought between 2007-2010 in Syria actually was a significant contributory factor to the war (Kelley et al., 2015). Low crop yields caused a displacement of many families to urban areas where there was a strain on resources, fuelling anger and resentment.

The conflicts mentioned so far have been internal ones within a country, caused by a general lack of water as a natural resource, and then poor allocation of it by an either inept or corrupt government.

But of course there are other types of conflict. The main problem with water is deciding who has the right to take what from the water supply. If a river runs through multiple countries, and the first country it runs through withdraws the majority of the water from it, then this will inevitably lead to water shortages in those downstream countries.

This article on the BBC discusses how tensions are rising in central Asia due to a gradual collapse in the system which saw five countries (Kazakhstan, Uzbekistan, Tajikistan, Turkmenistan and Kyrgyzstan) exchange water and energy, resources in which some countries were rich in whilst others weren’t. The fall of the USSR meant no one was regulating the exchanges between these countries. Therefore Uzbekistan (rich in natural resources which generated electricity) realised they could make more money selling electricity to richer neighbours, meaning less for Tajikistan and Kyrgyzstan. These countries in response needed to use more water to generate electricity. The result has been chronic water shortages leading to failure to grow crops in the downstream countries, and power shortages in the upstream countries. This has led to serious clashes between citizens of the affected countries.

A recent article in the NY Times raised the point in 2014 that ‘Syria’s government couldn’t respond to a prolonged drought when there was a Syrian Government. So imagine what could happen if Syria is faced by another drought after much of its infrastructure has been ravaged by civil war’. 4.8 million people have fled Syria since the civil war began, whilst another 6.6 million are internally displaced. The country currently is in disrepair with little hope of an end to the conflict coming soon. Kelley noted in his paper that droughts such as those experienced in Syria are now more than twice as likely in the Eastern Mediterranean due to human induced climate change. It does not seem that we will need to imagine much longer.

Where does it come from and where does it go?

 It takes 150 gallons of water to produce a single loaf of bread and almost 40,000 gallons to produce a car. In short, fresh water is essential to life on Earth, with agricultural, industrial and public use the three main areas of consumption. Looking at a simple map of the Earth it is clear that water is an abundant resource although only 2.5% of this is fresh water (fresh water is defined as water with less than 500 parts per million of dissolved salts) and fit for use in the previously mentioned activities. Most fresh water exists as glaciers and ice caps in the Antarctic and Arctic circles meaning it is unable to be exploited. Another 30% occurs as groundwater which is often hard to access. That means only roughly a quarter of fresh water used on Earth comes from groundwater sources. This leaves around 0.03% of the total global water supply available to humans at the surface. Of that number 69% of this exists as snow, ice and permafrost meaning only around 21% remains as lakes and rivers, the most obvious source of fresh water.

Currently, around 70% of globally accessible water is used for agriculture, although this increases in more arid areas, or countries where agriculture makes up a more significant proportion of the economy. The figure stands at around 20% for industry, although that rises to over 50% in industrialised nations.

The UN predicts a global population of 9.7 billion people by 2050. This, in turn will bring about a huge increase in demand for food, general products such as cars and clothes, and energy, all of which use vast amounts of water. However we are already exploiting our fresh water resources at a rate many may conceive as unsustainable, as it was shown in 2015 that 21 of the world’s largest 37 aquifers (a body of permeable rock that stores groundwater) were being depleted faster than they were naturally refilled by the hydrological cycle (Richey et al., 2015). Likewise, numerous large rivers such as the Colorado River and the Amu Darya (which used to feed the Aral Sea – now 10% of its original size) are no longer reaching the sea because their flow levels have been reduced so severely due to being over tapped.

Earth’s freshwater resources are unevenly distributed and currently almost one in 10 people ‘lack access to improved drinking water sources’. As the Earth's population increases and climate change continues to take effect, we can expect a growing challenge to humanity to ensure that developing countries and arid regions, where fresh water is economically and physically sparse, are able to access clean and safe water. 

This blog will aim to explore various issues regarding water scarcity, and the varying consequences of this problem as well as how it is tackled.