Climate change, water, and drought! Directly related terms! Climate change makes water-scarce, leading to drought: No drinking water on Earth! Scary but a fact!
As the term itself indicates, climate change refers to changes in climate that take place across the planet and have effects that can already be seen in many of its parts.
Water is one of the natural resources adversely affected by climate change, considering changes in precipitation patterns and the availability and distribution of river flow.
Climate change also alters the rainfall regime that can increase the occurrence of extreme hydrological events, such as long periods of drought and flood. These events affect the supply of water, threatening the supply of water resources for all.
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UN report on World Water Day, 2020
“Water and climate change” was the theme shared this year by the United Nations (UN) and the World Meteorological Organization (WMO) on the occasion of World Water Day (March 22) and World Meteorological Day (March 23).
The report states that the hydrological alterations caused by climate change constitute a challenge added to the sustainable management of water resources.
Climate change manifests itself in different ways: heat waves, heavy rainfall, storms, and storm surges.
The increase in the temperature of the water resource affects the quality of the water itself, reducing dissolved oxygen with a consequent reduction in the self-purification capacity of water bodies.
It is estimated that for every degree of global warming, approximately 7% of the world’s population will be exposed to a decrease of at least 20% in renewable water resources, according to the UN-Water Policy Report on Climate Change and the Water of the UN-Water organization.
According to the same report, the impact is differentiated and uneven by type of region, since while some regions go through extraordinary periods of drought, others suffer increasingly severe and frequent floods and storms, and others face both extremes.
Coastal areas, for example, face accelerated sea-level rise, threatening the lives of nearby communities.
The danger of rising sea levels is expected to increase in parts of South Asia, Southeast Asia, Northeast Asia, tropical Africa, and South America. Climate change is expected to increase the droughts frequency in many of the already dry regions in the coming decades.
However, the climate change impacts disproportionately affect the poorest and most vulnerable communities, compounded by other factors, such as population growth, migration, changes in land use, accelerated extraction of groundwater, and the loss of biodiversity.
UNICEF Report
According to UNICEF, at least 60 million girls and boys live in areas with low access to clean water and are at risk of droughts or floods. Few families can afford to migrate during droughts, forcing them to depend on contaminated water supplies.
UNICEF assures that more than 300 million girls and boys live in areas with high flood risk. Flood water can contaminate water supplies, spreading disease and increasing poverty.
When they lack clean water, says UNICEF, children are exposed to the danger of diseases such as diarrhea. More than 800 children worldwide die every day from diarrhea caused by unsafe water, poor sanitation services, and inadequate hygiene practices.
IPCC Report
In the Fourth Scientific Report of the IPCC AR4, there is evidence that climate changes can significantly affect the planet, especially concerning climate extremes, with greater intensity in less developed countries in the tropical region.
Over the years, it has been proven that most of the less developed countries are already facing uncertain and irregular periods of rain, and forecasts for the future indicate that climate change will make the water supply less and less predictable and reliable.
Water scarcity, aggravated by climate change, can cost some regions up to 6% of their GDP, stimulate migration, and generate conflicts, according to the World Bank 2016 report.
The overexploitation, degradation, and contamination of surface and underground water have reached alarming proportions and may compromise the water supply at present if no action is taken.
Impact of Climate Change on Drinking Water Sources
Rising temperatures, rainfall extremes in frequency and intensity, an anticipated rise in sea levels, an increase in forest fires, and droughts are just some manifestations of climate change that could affect the drinking water sources.
The impact could be particularly significant on surface water, which provides 80% of all drinking water.
- A strengthening of the drought/re-humidification cycle could be particularly worrying since it is known that it promotes organic matter decomposition and allows greater leaching into surface water during re-humidification episodes.
Here are the major impacts climate change can have on drinking water sources.
1. Change in Hydrological Cycle
The earth’s hydrological cycle is directly associated with atmospheric temperature and radiation balance changes. It continuously distributes water from the oceans to the atmosphere and rivers and lakes.
Changes in this cycle increase water vapor levels in the atmosphere and make the availability of this resource less predictable.
It means that evaporation increases, altering soil moisture, rainfall, and, consequently, water availability for human consumption.
The world is already experiencing large-scale changes in places like the Andes and the Himalayas, where glaciers are disappearing and taking the source of drinking water and irrigation for thousands of people.
Kathmandu or La Paz depend on the glaciers of the Himalayas and the Andes, respectively, so they can be seen without the necessary water.
In addition, it can cause, among other factors, torrential rains in some regions, while others may face severe drought conditions, especially during the summer.
As a result of global warming and the increase in the emission of greenhouse gases, the heat trapped in the atmosphere ends up being stored in the oceans, affecting the temperature and circulation of water and accelerating the melting process of the polar ice caps.
This situation results in freshwater entry into the oceans, altering marine currents and the hydrological cycle, and increasing sea levels in coastal regions.
In addition, rising water temperatures because of climate change contribute to the expansion of dead zones — regions poor in oxygen and uninhabitable for marine life within the oceans.
For society, the problems directly impact the availability of water to supply the population.
As a result, the problems of lack of resources for health and quality of life of people and the social context stand out; after all, a large part of economic activities depends on water.
2. Acidification of Ocean water
Rainwater, drinking water, the climate, the coastal environment, much of the food, and half of the amount of oxygen we breathe are regulated by the oceans.
Today their balance is in danger due to climate change, overfishing, and pollution, especially that caused by plastic.
Oceans are warming faster than expected. Their levels are rising due to melting glaciers, carbon dioxide makes the water more acidic, resulting in damage to coral reefs, and many marine species are at risk of extinction.
The oceans mitigate the impacts of atmospheric pollution because they absorb about 30% of the CO₂ produced by human activities.
But the price we pay for this carbon dioxide storage is the acidification of the water. When CO₂ is absorbed, a series of chemical reactions are triggered that modify the pH of the oceans.
Over the past 200 years, water basicity has dropped by 0.1 units, going from 8.2 to less than 8.1 pH, resulting in a 30% increase in acidity.
If greenhouse gas emissions continue at current levels, the oceans will become 150% more acidic over the next century, reaching a pH level never seen in 20 million years.
3. Degradation of water sources
In recent times, the global concern is increasing that droughts could become more frequent and prolonged due to climate variability and change and cover areas that have not yet been affected.
It is one of the harshest consequences of climate change, being increasingly severe and frequent. In addition, the historical series confirms that they increasingly affect the driest geographical areas, thus increasing their extension in time and quantity.
Responses and reactions to droughts in most parts of the globe tend to be related to crisis management and are known to be delayed, poorly coordinated, and fragmented.
As a result, the economic, social, and environmental impacts of droughts have increased significantly worldwide. Of all types of natural disasters, due to their long-term socioeconomic impacts, droughts are by far the most damaging natural disaster.
Rising water temperatures and low runoff conditions resulting from drought are projected to degrade water quality.
As a result, groundwater sources near coastal areas may be dwindled, leading to saltwater intrusion into groundwater-based water supplies.
4. Change in behavior of oceans and water cycle
The upsurge in global temperature modifies the behavior of the oceans and water cycles. According to the United Nations Office for Disaster Risk Reduction, floods, storms, heatwaves, droughts, and other meteorological phenomena caused more than 90% of major natural disasters in the last decade.
These weather events wash away entire water supplies or contaminate them with loads of sediment, nutrients, and pollutants. It affects freshwater ecosystems and consequently their human consumption.
5. Increased Water Evaporation
Warmer air can hold more moisture and humidity than cold air. As a result, the air will absorb more water from the oceans, lakes, soil, and plants in a warmer world.
The drier conditions that this air leaves behind could negatively affect drinking water supplies and agriculture.
On the other hand, warmer and more humid air could also endanger human lives.
A study by the Lamont-Doherty Earth Observatory at Columbia University found that higher humidity will make future temperatures unbearable in some places by blocking the cooling effects of our sweat.
6. Unpredictability of Precipitation
Climate change will make it even more problematic to predict the amount of precipitation that may fall from the sky.
In addition, the nature of this will be more irregular, with a familiar scenario marked by unusual torrential rains, followed by long periods of drought. But it is not only a question of water scarcity: the impact will also be remarkable in its quality.
This quality can be diminished by intense rainfall since it will increase runoff from rivers and streams that carry pesticides, herbicides, and other chemical products of agricultural and urban origin.
At the same time, increasing the air temperature will also increase that of the water.
This situation, among other things, will increase evaporation, simultaneously reduce oxygen levels and deteriorate its quality.
The list of changes is extended since heating the planet’s water implies a significant environmental transformation.
When extra warm and humid air cools down, extra rain or snow falls on the ground. So a warmer world means we are hit with heavier rains and snowstorms.
The warmest areas of the planet are experiencing a tremendous increase in the intensity and frequency of heavy rainfall events so far.
Another consequence of warmer water is the proliferation of algae, which complicates and makes its treatment more expensive. In the long run, many regions do not have the necessary water quality.
7. Modification of incoming and outgoing flows
The water recharge of underground aquifers, particularly free aquifers, is done through the infiltration of rainwater. This recharge, therefore, depends on precipitation.
The various studies on climate change show, as a general rule, a decrease in precipitation, especially for the summer period. To this would be added an increase in evapotranspiration, further reducing the water actually infiltrated.
The decrease in the flow entering the system would change the recharge conditions of hydrogeological systems.
Concerning outflows, there is a close relationship between watercourses and underground aquifers. Generally, the rivers feed the water tables in winter and are fed by the latter in summer.
If the watercourses are brought to experience more extended periods of low water, then the groundwater would play a more critical role in supplying the watercourses.
The volume of water from the groundwater would then be greater and spread over a longer period.
In winter or when there is high water, the watercourses feed the water tables. Thus, a decrease in the flow of watercourses would lead to lower groundwater recharge in winter.
8. Scarcity in resources and expensive water
Climate change causes greater fluctuations in groundwater levels. On some days, drinking water will become scarce in some regions.
More user groups, communities, and nations will compete for a resource becoming more and more scarce. The focus is on the dry and hot summer days, when the water demand is high and which the water supply industry calls peak load periods.
According to meteorologists and climate researchers, water demand will increase in the future. It has negative consequences for the drinking water supply.
Some nations have already banned drinking water usage in filling up swimming pools, washing cars, or sprinkling the lawn.
After all, the water suppliers and the government cannot simply expand their subsidies on critical days when water consumption is high.
To deliver enough drinking water to the population in the long term, the supplier relies on a more extensive pipeline system.
They need the finance to build new wells and reservoirs, find new drinking water sources, new pipelines, do more extensive environmental monitoring, and expand plants and elevated tanks for water storage.
It all costs money, and ultimately it is the consumers who have to pay these additional expenses.
9. Absence of Water circulation in winter
Most of the year, the water in the lake, rivers, and reservoirs is stratified according to its temperature, i.e., warm water is in the upper layers, cold water in the lake’s depths.
In winter, the water cools down, and when the entire body of water is roughly the same temperature, the water is mixed from top to bottom: the circulation.
Should this circulation fail for a longer period, deep layers will not receive any more oxygen, and oxygen-free conditions could arise at the bottom of the lake and river.
These would set chemical processes in motion to release various substances (e.g., phosphate) from the sediment. The result would be pollution of the lake and river.
Conclusion
It is not just about turning on the tap and being able to drink water, take a shower, or cook. The essentiality of water as a resource is fundamental and is highly linked to the behavior of the earth’s climate system.
The solution to the problem of quality and supply of water is not new, but it is increasingly evident. If we want to prevent environmental change from further reducing our accessibility to drinking water, we need to reduce something else first, the consumption of fossil fuels.
In 2020 we fought against a severe pandemic, and we are still fighting. At the time, without realizing it, we have also temporarily fought against another that has been occurring for a long time, called anthropogenic climate change.
It may be a suitable time to bet on energy alternatives and, at the same time, look for new ways to exploit the increasingly limited resources that the earth provides us.
(Last Updated on April 11, 2022 by Sadrish Dabadi)
