Our Planet is changing every day. Rising local temperatures, melting glaciers and unexpected natural calamities are the proof of it. These changes are seen in terms of Ground water resources too.
Ground water accounts for a smaller percentage of total earth’s water. But it is important to bring to notice that the ground water contributes to thirty percent of total fresh water that is available. Thus, it is an important source of fresh water on earth. It plays a crucial role in sustaining the ecosystems and making life possible. Over 1.5 billion people depend on ground water even today for their primary needs especially in countries of the Global South.
What Is Ground water?
Ground water is a component of water resources that is extracted from aquifers through artificial methods like pumping wells. It is found under the ground in the cracks and spaces of rock, sand and soil. It is used for various purposes like drinking, irrigation, industrial processing, etc.
Impacts of climate change on ground water:
1.Sea level rise: Sea Level rise is a secondary impact of climate change due to thermal expansion and glacier melting. There is significant & consistent available data, about immense rise in the sea level along the Indian coast. A rise of about 1.33mm/year is observed. Sea level rise leads to leakage into ground water aquifers (mostly in coastal areas). The balance of salt content in the freshwater gets disturbed due to the water ingress. This impacts and threatens the freshwater resources with salinization leading to non-potable water. This - contaminates freshwater ecosystems - effects the available quantity and quality of ground water - Affects the soil quality of agricultural land due to high saline content of water
Sea Level Rise — A threat to all Coastal Regions & Small Islands (https://www.earth.com/news/sea-levels-are-rising-at-an-alarming-rate/)
It is estimated that by 2025, 75% of the world’s population is going to stay in coastal areas. Hence, undoubtedly, this is going to challenge the entire world. By 2050, the gross per capita water availability will decrease from 1820 m3/year to 1140 m3/year in India itself. Climate change will alter the future of freshwater resources at an alarming rate.
2.Excessive consumption of groundwater: Rise in temperatures escalates the evaporation and transpiration rates. These rates consequently influence the time and intensity of precipitation thereby creating a variation in overall rainfall pattern. This also means that groundwater levels are going to fluctuate very frequently. This fluctuation affects the crop production as well as agriculture that is rain fed.
Drought Conditions — Already being experienced in areas of Africa and Madagascar (https://www.preventionweb.net/news/13-year-drought-creates-frightening-new-normal-south-america)
Secondly, drought-conditions and heated regions require higher water quantity for usage. To compensate this, ground water is drawn in excessive quantities leading to a point of scarcity for current and future generations.
So, altered precipitation rates and extreme weather conditions could potentially lead to prolonged period of droughts where a higher risk of depletion of water resources is likely to be observed.
3.Ground water recharge: Ground water recharge primarily depends on precipitation and other climatic factors. Unpredictable precipitation rates and intensities result in low or no amounts of ground water recharge in fewer months and concentrated recharge in other months. Thus, creating a tragic imbalance in recharge of ground water.
An illustration of Ground water recharge (https://en.wikipedia.org/wiki/Groundwater_recharge)
4.Ground water contamination: Climatic change and sea level rise causes salt water intrusion leading to brackish water. The reversing process of salt intruded water is difficult. Therefore, huge amounts of fresh water gets polluted reducing the percentage of fresh water reserves.
An illustration of Ground water recharge (https://en.wikipedia.org/wiki/Groundwater_recharge)
5.Change in runoff pattern: Climate change affects the ice caps and glacier melting rates. It also alters and reduces the snow cover area that is present. So, this changes the overall runoff pattern thereby affecting ground water quantity.
With the changing climatic conditions there will be impacts on the amount of recharge, discharge, storage, quality and quantity of ground water, directly or indirectly.
Although climate change is recognised widely, its impacts on ground water have often been neglected. This creates a need for ground water to have a more prominent role in climate change discussions and mitigation action. With the increased level of exploitation and deterioration of groundwater it is important to understand and create awareness in regards to protect and safeguard the available ground water.
To make the invisible, visible.
References: Wu, WY., Lo, MH., Wada, Y. et al. Divergent effects of climate change on future groundwater availability in key mid-latitude aquifers. Nat Commun 11, 3710 (2020). https://doi.org/10.1038/s41467-020-17581-y
Green T.R. (2016) Linking Climate Change and Groundwater. In: Jakeman A.J., Barreteau O., Hunt R.J., Rinaudo JD., Ross A. (eds) Integrated Groundwater Management. Springer, Cham. https://doi.org/10.1007/978-3-319-23576-9_5