The talk focused on the limited global freshwater supplies that are being drained dry through unsustainable use. Fred Pearce used many examples throughout the seminar of areas that have used freshwater unsustainably and highlighted how important it is to not waste the precious resource that is essential for life. Sustainable solutions were also discussed, with an underlying message about how people need to change the way they use water, on a day to day basis to prevent a future water crisis.
Blog Theme: The scarcity of freshwater resources and the unsustainable use of freshwater and how to combat this.
Ongoing Blog Theme: climate change on Earth: past and present – the things that have and will change and what we can do about it
Water is essential for life and yet is a dispensable resource for most humans – it is taken for granted. When you consider how often you use water in your daily life, and how vital it is for your quality of life, it is staggering.
Mekong River, an example of how important freshwater is for life
The Mekong is a huge river in Asia (see Figure 1, above) and flows for almost 5000 km, from China to the South China Sea, passing through Myanmar, Laos, Cambodia, Thailand and Vietnam on its journey to meet the sea. The river is a vital source of food and water for over 300 million people, providing a livelihood from fisheries for over 60 million people.
The river is the largest inland fishery in the world, the equivalent of a quarter of the world’s freshwater catch. 2/3 of the worlds largest fish are found here, namely the Mekong giant catfish, the biggest fish on the planet but all of this is going to change (WWF, 2011).
Between winter and summer every year the Mekong floods with flows increasing up to fifty times base rates and water levels rising up to 9 metres (see Figure 2). This process occurs yearly due to the monsoons melting snow from the mountains, sending water cascading down the river. Due to this huge increase in volume each year, water can actually flow uphill from June to November, flooding areas of forest forming a large lake that forms a spawning ground for 2/3 of the Mekong rivers fish.
However, dams being built in China to provide hydroelectric power for people will start to tap the yearly monsoon floods. One of the dams will be as high as the Eiffel towel and there will be eight of them in total. The dams will end up holding back half the flow from the monsoons and this will result in the loss of the forest lakes and inland fisheries (see Figure 3). It is estimated that when the dams are up and running, the Mekong river will lose 90% of its fish.
Even though the dams haven’t yet been finished, flood variability is already being affected and fishing is already being affected. The damages that will occur downstream and the loss of livelihood to so many people counterbalances the benefits of hydroelectric power. Effectively, the Mekong river is being tapped by man and taken from the people downstream so that the resource can be provided to a different group of people up stream.
The damming of many rivers has already happened across so many rivers throughout the world, with many consequences for the people and animals that rely on the river as a source of life and livelihood. For instance, the Columbia river in the United States of America used to be a great salmon fishing ground, but after it was dammed, the salmon population, and consequently the livelihoods of many people, were decimated.
Water Statistics
Fred worked out many statistics involving the amount of water that it takes to produce many commonplace things that we take for granted:
· 11,000 litres of water are needed to produce one hamburger (all the water it takes to grow the grain for the bun and the water to raise a cow for the meat).
· It takes between 2000 and 4000 litres of water to produce 1 litre of milk from a cow.
· Humans in developed countries, on average, consume a hundred times their weight in water every single day via showering, food, washing and drinking.
· In a year, a person will have used enough water to fill an Olympic sized swimming pool.
Given there are over 7 billion people on the planet, this figure is quite staggering.
Water used to be thought of as an unlimited resource, except the amount of freshwater available on the planet for consumption is actually a very small resource that is replenished by the water cycle (see Information Box 1) and there is only so much water available in the water cycle each year.
For a summary of the water cycle, watch this video from NASA (2019):
Fred calculated how much fresh water there is available each year – there is 9000 km³ of water available each year for all the people on the planet. This works out as 1200 m³ of water per person per year yet the demand for water is actually double this figure.
Unfortunately, if we continue to consume so much freshwater at our current pace then there is greater demand than there is supply. It is for this reason that the rivers are running dry and there is a global shortage of water.
It’s hard to believe that the rivers will run dry, but it is actually already happening – for parts of the year the Nile, the Rio Grande and the Colorado river all run dry.
Due to demand there is:
· less water reaching the ocean
· less water in the water cycle
· a deficit of freshwater
The rest of this blog will go into detail about some case studies of where demand outweighs the supply of freshwater. On a lighter note, I will also discuss some sustainable ways to collect freshwater and case studies of where this is being done.
The Aral Sea
Once the worlds fourth largest lake, the Aral Sea (a salt water lake), was surrounded by prosperous fishing villages and lush wetlands. The water from the lake was used to irrigate cotton crops in Uzbekistan which are very thirsty crops – the creation of one cotton t-shirt uses 2,700 litres of water (Hoskins, 2014). The sea is now almost completely dried up due to evaporation in the hot sun and a lack of water replenishing the sea. The sea used to be the size of Belgium and the Netherlands combined but it is now a dead desert full of rusting fishing boats. The coast has retreated 100km since 1960 (see Figure 4).
Once the lake bottom was exposed, salt and pesticides have been spread throughout the surrounding populations, poisoning the land and the people. Carcinogenic dust causes throat cancers and respiratory diseases (Hoskins, 2014). Average life expectancy in the region is now 51 years.
Bangladesh
Due to health problems with sewage infiltrating the surface water supplies, locals decided to pump up underground water. Within a decade of this change to using underground water, more than 2 Ma wells have been sunk. However, people started getting ill and there was an increase in cancer types and skin legions. Over twenty million people drink the contaminated water in Bangladesh and over 20% of deaths in the region are linked to the arsenic (UofE, 2019). Each year, an estimated 43,000 people die from arsenic poisoning in the country (Jahan, 2016) (see Figure 5). Upon eventual testing of the underground water it was found that the water contained arsenic at concentrations hundreds of times greater than the World Health Organisations (WHO) recommended levels. This is because natural arsenic is being pumped up for consumption, irrigation and bathing.
There is no government system to check the water quality and the creation of wells is unregulated and so almost every household has their own well that could be high in arsenic. Each well is a lottery for the people drinking the water – some wells are safe as the arsenic levels depend on the depth at which the water is pumped up from. Sadly, no one knows the depths at which the wells are dug – not even the owners. A small water testing station was set up temporarily in which locals brought water for arsenic testing. Wells which gave unsafe levels were painted red, so they are known to be dangerous to stop their use.
The WHO has called the issue the worst mass poisoning of a population and that as many people are at risk today as there were ten years ago. The University of Edinburgh has developed a biosensor that can be attached to a smartphone for onsite testing of arsenic water levels. They want the technology to become widely available for Bangladesh and other areas in the world with contaminated water problems and to replace the other, harder to use existing tests (UofE, 2019).
Northern Syria
The area is very short of water due to the arid conditions and so for more than 3,000 years, ancient channels called qanats have been used to channel water sustainably into villages for agricultural and domestic use (Taghavi-Jeloudar et al, 2013) (see Figure 6). Rainwater is tapped and channelled into the villages by gravity along the channels into storage tanks so that nothing is wasted. Villages receive a constant channel of water due to the angle at which the channels are dug. Without their channels, the villages wouldn’t have survived, and the area would have been abandoned (Word Bank , 2018).
Qanats offer a sustainable way to battle water scarcity in the coming years, especially in areas where water will become a rarity due to climate changes (Taghavi-Jeloudar et al, 2013).
India
The rivers and wells in India are running dry as the water table has been lowered significantly due to unsustainable use for crop irrigation. Farmers are now trying to use sustainable techniques to take advantage of the monsoon rains. Farmers construct shallow walls that channel water from the rains into storage areas. It was an old and traditional technique that has now come back into fashion and is very popular as people are struggling due to the water scarcity. Villages using these methods now get three harvests a year compared to one harvest in villages that don’t use the walls. There is no more or less rain in India, the rain is just utilised in a more efficient way than before.
Suitability of the techniques
There are several techniques that have been used throughout this post:
· App for water testing
· Monsoon walls
· Gravity channels
· Desalination of seawater
App for water testing
The technique is very new and still widely unavailable and expensive. In time it could become an invaluable resource for areas that suffer from poor water quality. Although it provides readings on levels of arsenic in water and will allow the user to check if they have safe levels, it is not a solution to the widespread problem. To combat arsenic poisoning, other ways to access uncontaminated freshwater must be found.
Monsoon walls
Constructing low walls to channel monsoon rainwater into storage ponds for domestic and agricultural use is a very inexpensive technique that is easy to use and build. The technique is able to effectively capture the excess rainwater so that the valuable freshwater is not wasted. The technique is very suitable and sustainable and so would be easily transferred to other countries with high rainfall and few freshwater sources.
Gravity channels
Gravity channels are an old technique and the infrastructure is already in place in certain places. Since qanats have been used for 3,000 years they can be created without modern technology or expense. They are very suitable for arid areas with surrounding hills or high areas and provide water constantly for areas once they are installed. For this reason, the technique is very suitable as it is a relatively inexpensive and sustainable method for combating water scarcity.
Desalination of Seawater
Although not mentioned as a technique in this blog, the technique was discussed during the seminar by Fred. It is commonly used throughout the Middle East in countries like Saudi Arabia, Kuwait, the United Arab Emirates and is extremely useful in areas where fresh water is scarce and sea water is readily available (USGS, 2018). The Thames estuary actually has a back-up desalination system in place to combat any future water scarcities that the South of England could face.
However, the technique is not very suitable as a solution to freshwater water scarcities as the technology is expensive and therefore not readily available for developing countries that require inexpensive and simple solutions that they can implement.
Although not suitable at the present time, the technology may improve to make it cheaper and more widely available. For now, only 3-4% of the worlds water supply comes from desalination.
How did the talk advance our knowledge?
The talk showed how important water is for our lifestyles, yet freshwater supplies are being drained through unsustainable practices that humans are using to tap into freshwater reserves. Through serious case studies, it became very clear how vital it is to find sustainable ways to supply freshwater for areas that are suffering from drought, contaminated water and dams. To really tackle this global problem, changes in the ways we use water as individuals and as a population must be made.
Thanks for reading!
My final blog will be about sea level changes that are being mapped in Greenland through salt marsh records and is related to climate changes and sea level rises.
References
African Water. (2003). Mekong River Basin. Available at: https://www.africanwater.org/mekong_river.htm [Accessed: 30/03/2019]
Hecht J.S, Lacombe G, Arias M. E, Dang T.D, Piman T. (2019). Hydropower dams of the Mekong River basin: A review of their hydrological impacts. Journal of Hydrology, 568, 285–300.
Hoskins, T. (2014). Cotton production linked to images of the dried-up Aral Sea basin. Available at: https://www.theguardian.com/sustainable-business/sustainable-fashion-blog/2014/oct/01/cotton-production-linked-to-images-of-the-dried-up-aral-sea-basin [Accessed: 31/03/2019]
Jahan, H. (2016). Arsenic in Bangladesh: how to protect 20 million from the world's largest poisoning. Available at: https://www.theguardian.com/global-development-professionals-network/2016/oct/18/arsenic-contamination-poisoning-bangladesh-solutions [Accessed: 31/03/2019]
LinkedIn. (2019). Fred Pearce. Available at: https://www.linkedin.com/in/fred-pearce-72567932 [Accessed: 30/03/2019]
Loewenberg S. (2017). The Poisoning of Bangladesh. Available at: https://undark.org/article/bangladesh-arsenic-poisoning-drinking-water/ [Accessed: 31/03/2019]
NASA. (2019). The Water Cycle. https://www.e-education.psu.edu/earth103/node/888 [Accessed: 30/03/2019]
Taghavi-Jeloudar, M., Han, M., Davoudi, M, Kim, M. (2013). Review of ancient wisdom of Qanat, and suggestions for future water management. Environmental Engineering Research, 18, 57-63.
UofE. (2019). Smartphone test spots poisoned water risk. Available at: https://www.ed.ac.uk/news/2019/smartphone-test-spots-poisoned-water-risk [Accessed: 31/03/2019]
USGS. (2018). Saline water: Desalination. Available at: https://water.usgs.gov/edu/drinkseawater.html [Accessed: 31/03/2019]
Word Bank. (2018). A New Irrigation Canal in Northern Afghanistan Boosts Farmers' Production. Available at: https://www.worldbank.org/en/news/feature/2018/11/22/irrigation-canal-rehabilitation-benefits-farmers-in-northern-afghanistan [Accessed: 31/03/2019]
WWF. (2011). Conserving the Mighty Mekong River. Available at: http://www.wwf.sg/?200000/conserving-the-mighty-mekong-river [Accessed: 30/03/2019]
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