There is a finite quantity of fresh water on earth, and a quantifiable amount available for use by humans. Dr Anjani Ganase looks at the challenge of maintaining water supplies at satisfactory quality levels in all habitats.
Heavy rainfall over the last few weeks, and more recently last Friday in Tobago and Saturday in Trinidad, filled our rainwater tanks – all 1,800 gallons – in less than ten minutes, the same time it took to flood the rivers, cascade onto streets, and cause a three-hour traffic jam on major highways. The future projection for water distribution with the changing climate sees some places getting wetter (tropical zones), while other places will get drier (temperate zones). It also predicts more intense rainfall and periods of drought.
On a daily basis, we are flooded with reports of both wildfires and devastating floods. Areas that are wetter and more prone to flooding include the Amazon and the Orinoco basins. It is unclear where Trinidad and Tobago falls along the spectrum of shifting rainfall, we are expected to experience more intense bouts of rainfall along with hotter and drier dry seasons in the future. While global impacts are largely the results of climate change, the threat of water shortages and scarcity around the world is largely driven by our current unsustainable relationship with water. The world is nearing a water crisis that will only be exacerbated by climate change. Let’s look at our current relationship with water and how we might circumvent the impending crisis.
All the water we need
Of all the water present on the planet, less than one per cent of the water is accessible via freshwater systems (aquifers, rivers, lakes etc). This small portion is what supports most terrestrial ecosystems, and all seven billion people living on the planet. Over the last century, we have improved water extraction processes by piping, damming and pumping water away from natural ecosystems. At the same time, we inject polluted water waste back to nature without understanding the consequences on the water cycle. We will not run out of water but are likely to run out of supplies of clean water. Groundwater supply accounts for most of the water around the world and many places are on overdraft.
Seventy per cent of the freshwater goes to agriculture: water not just for crops through irrigation, but also for the crops used in feeding livestock. The second largest consumers of water are production and processing industries (20 per cent). This leaves ten per cent of the water for domestic consumption. It is expected that domestic and industry water demands will increase rapidly by 2050 as the global population increases to over nine billion people. While agriculture will not increase as intensely, it will continue to be the largest component of water use. Geographically, the areas where water demands will increase the most include Africa and Asia as livelihoods improve. However, while parts of Africa have become wetter, large sections of Asia, including China, India and the Middle East, are already suffering from more droughts that are likely to be worse in the future.
Industrial and agricultural water
All the water used by us becomes significantly reduced in quality and is not treated for recirculation back into nature. Currently, 80 per cent of industrial and municipal wastewater globally is discharged without treatment. The contamination of river and ground water supplies includes worst of all, the nutrient loading from agriculture where nitrogen and phosphorus drive pathogens that result in disease outbreaks in humans and nature, as well as in algae blooms in river and coastal ecosystems that devastate the local habitats. Globally, the use of fertilizers is expected to increase by nearly 1.6 times with significant consequences to downstream waterways. Apart from nutrients, other agricultural chemical loading includes pesticides, fungicides and weedicides that leech into water pathways. At home and from our businesses, we discharge domestic cleaning products as well as hormones, pharmaceuticals, fragrances, body products daily. In many cases sewage is also discharged without treatment. There are serious consequences to biodiversity and downstream habitats. Particular to coastal cities and islands is the over extraction from coastal aquifers, which can result in land subsidence or compaction along with saltwater intrusion as a result of sea-level rise.
Loss of biodiversity
Arguably, the agricultural sector has had the biggest impact on biodiversity of habitats, directly, from the conversion of our forests to grasslands and the relocation of water to irrigation for crop production and grazing. Mass monocultures have also reduced the quality of the soil and result in a heavier dependency on fertilizers that pollute downstream habitats. Currently the world’s forested areas make up about 30 per cent of the land; and about 65 per cent of the forests are degraded. Other major habitats that depend on a stable supply of water in our coastal areas, are wetlands. The influx of freshwater and nutrient-rich sediments into wetlands (mangroves, deltas and estuaries) create a unique habitat to support wildlife nurseries. Over the last 300 years, we have lost 87 per cent of wetlands and delta ecosystems, most from the clearing of areas but many have dried up because of piping and damming. The loss of these natural coastal absorbers of water, and at the same time, the increase in the development of coastal cities largely constructed with impermeable hard structures have fast tracked the polluted runoff into surrounding marine ecosystems.
Cities and built environment
The city of Port of Spain is five square miles, the majority of which is covered in hard surfaces. This means that all the water and sediments from the hills no longer settle in the low-lying coasts but gets flushed directly and immediately into the ocean. Most of the flushed water carries pollutants, sediment, chemicals and garbage. This trend is common for most coastal cities worldwide. Water pollution has claimed about 30 per cent of the global biodiversity because of degraded water ways. By 2050, while the demand for water will be higher, the availability and quality of water will be reduced, Soil quality and biodiversity in all ecosystems will be more degraded.
Strategies for improvement require more regulations, nature-based solutions, and eco- engineering to resolve issues in the short and long-term. Agriculture is the primary concern, and improvements of irrigation are necessary. Simple management of irrigated water to balance farms and natural habitats has resulted in rebounding lakes and river ecosystems. Downstream pollution should also be regulated and treated. Research into trees and plants bred to tolerate less water and poor soil conditions is important.
Whether we live in a drought or flood prone area the conservation of clean water is of paramount importance. All water is connected. An example of smart water management and recycling includes a sewer mining operation where a golf club in Sydney Australia decided to tap into the city sewer lines to nourish their golf course and gardens. This reduced the nutrient loads of the city’s wastewater and reduced the discharge quantities. China embarked on making their major cities more spongey to absorb and capture water runoff.
What I can do
Personal conservation of water does matter, and most effective would be the selection of meat products that have lower water demands: beef requires four times the water to produce over chicken; the high maintenance of beef also relates to the high carbon footprint and forest loss. The conversation about smarter and sustainable food choices is essential. Unsustainable water usage and waste removal are driving the water crisis. The solution must be to re-insert ourselves into nature’s water cycle. Remember that in nature there is no waste.
Boretti, Alberto, and Lorenzo Rosa. "Reassessing the projections of the world water development report." NPJ Clean Water 2.1 (2019): 1-6.
World Water Assessment Programme (Nations Unies), The United Nations World Water Development Report 2018 (United Nations Educational, Scientific and Cultural Organization, New York, United States)
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