UPSC CARE 10th September 2025 Current Affairs

Why in News?

International scientists recently confirmed the presence of a large offshore freshwater aquifer beneath the Atlantic Ocean, stretching from New Jersey to Maine, with potential significance for global freshwater resources.

Introduction

• Nearly 50 years ago, a U.S. government ship drilling off the northeastern coast of the United States accidentally encountered freshwater beneath the sea floor while searching for minerals and hydrocarbons.
• Recently, an international group of scientists revisited this surprising discovery and confirmed the presence of a vast offshore aquifer—a body of porous rock or sediment saturated with freshwater—stretching from New Jersey to Maine.
• In a landmark effort, the scientists drilled nearly 1,289 feet beneath the sea floor and extracted about 50,000 liters of freshwater for detailed analysis.
• Brandon Dugan, a geophysicist and hydrologist from the Colorado School of Mines, highlighted the unexpected nature of the discovery: “It’s one of the last places you would probably look for freshwater on Earth.”
• This discovery has significant implications amid growing concerns over global freshwater scarcity, making it crucial to understand the nature, origin, and potential of offshore aquifers.

(image Source: Indian Express)

What Are Offshore Aquifers?

• Offshore aquifers are analogous to terrestrial aquifers but located beneath the sea floor. These geological formations contain freshwater trapped within porous rocks or sediment layers.
• Unlike conventional aquifers on land, offshore aquifers can extend up to 90 kilometers off the coast, and astonishingly, studies estimate that they contain more freshwater than all groundwater ever extracted from terrestrial aquifers.
• A 2021 study published in Environmental Research Letters estimated that approximately one million cubic kilometers of freshwater—roughly 10% of all terrestrial freshwater—resides beneath the world’s ocean floors.
• Such aquifers have been identified in regions off the coasts of Australia, China, North America, and South Africa, though they remain largely unexplored due to the historical focus on land-based aquifers and technological constraints.
• The recent expedition marks the first systematic global attempt to drill specifically for undersea freshwater, and the scientists estimate that the northeastern U.S. aquifer contains enough freshwater to supply New York City for 800 years.

Origin of Freshwater in Offshore Aquifers

• Unlike onshore aquifers that primarily receive freshwater from precipitation (rainfall and snowmelt), the presence of freshwater beneath the sea floor is explained by competing theories:
• Ice Age Hypothesis:
  • During previous ice ages, sea levels were significantly lower, and large areas currently submerged under oceans were dry land. During this period:
  • Rainwater penetrated the soil and percolated deep into the ground.
  • The immense weight of growing ice sheets possibly forced freshwater into porous rocks extending beneath the continental shelf.
• Connection to Onshore Aquifers:
  • Another theory suggests that offshore aquifers remain connected to terrestrial aquifers, with periodic replenishment occurring through infiltration from rainfall and natural hydraulic gradients.
  • An important factor that preserves the freshwater within these offshore aquifers is the presence of a cap rock layer—compact clay-rich sediments. As noted by Scientific American, clay becomes almost impervious when compacted, effectively preventing the less dense freshwater from rising and mixing with the overlying salty seawater.
  • The current scientific mission involves extracting thousands of samples to ascertain whether the freshwater is non-renewable (from the Ice Age) or part of a renewable system connected to surface processes.

Significance of Offshore Aquifers

• The global freshwater crisis is one of the most pressing challenges of the 21st century. According to a 2023 United Nations report:
  • Global freshwater demand is projected to exceed supply by 40% by 2030.
  • Rising global temperatures have contributed to:
  • Increased frequency of droughts.
  • Altered rainfall and snowfall patterns, which reduce aquifer recharge.
  • Pollution and wasteful water practices.
• Johan Rockstrom, Director of the Potsdam Institute for Climate Impact Research, termed the situation a “triple crisis”—misuse, pollution, and climate-induced hydrological change.
• In this context, offshore aquifers represent a potentially vast and largely untapped freshwater resource.
• Their development could relieve pressure on land-based freshwater sources, providing an alternative solution to growing demands, especially in densely populated coastal regions.

Challenges in Exploiting Offshore Aquifers

Despite the potential, several challenges complicate the large-scale utilization of offshore aquifers:

• High Extraction Cost: Offshore drilling for freshwater is highly expensive. The recent project in the U.S. northeast cost around $25 million, posing significant economic challenges for scalability.
• Engineering Complexities: Extracting freshwater beneath the sea requires:
  • Designing specialized wells that operate under high pressure and prevent seawater intrusion.
  • Establishing safe and effective transport infrastructure to carry freshwater onshore.
  • Implementing advanced pumping mechanisms to avoid mixing freshwater with salty seawater.
• Environmental and Ecological Impacts: There is significant uncertainty about the ecological consequences of extracting freshwater from offshore aquifers. Impacts on marine ecosystems, sediment stability, and coastal hydrodynamics are largely unknown.
• Ownership and Governance Issues: The question of legal ownership and resource management arises:
  • Who will regulate and control the extraction?
  • How will indigenous communities, fishermen, and coastal populations be involved in the decision-making process?
• Rob Evans, a geophysicist, cautioned: “If we were to go out and start pumping these waters, there would almost certainly be unforeseen consequences.”

Conclusion

• Offshore aquifers hold immense potential as a freshwater reserve in a world facing growing water scarcity. However, they remain a largely untapped resource due to high costs, technological challenges, environmental concerns, and governance complexities.
• Scientific studies, like the recent drilling off the U.S. northeast coast, mark the beginning of a new phase of exploration and understanding.
• For sustainable development and efficient resource management, it is essential to balance technological advancement with environmental safeguards and equitable governance structures. Given the looming global water crisis, offshore aquifers could, in the near future, serve as a critical buffer for freshwater security.

CARE MCQ

Q6. Consider the following statements regarding Offshore Aquifers:

1. Offshore aquifers are bodies of freshwater trapped beneath the sea floor, typically within porous rocks or sediments.
2. Freshwater in offshore aquifers is primarily replenished by direct rainfall and snowmelt, similar to terrestrial aquifers.
3. The existence of offshore aquifers is significant as they can help mitigate the global freshwater scarcity exacerbated by climate change.

Which of the statements given above is/are correct?

A) 1 and 2 only
B) 1 and 3 only
C) 2 and 3 only
D) 1, 2, and 3

Answer 6- B

Explanation

• Statement 1 is correct: Offshore aquifers are bodies of freshwater trapped beneath the sea floor within porous rocks or sediments.
• Statement 2 is incorrect: Unlike terrestrial aquifers, offshore aquifers are not primarily replenished by direct rainfall or snowmelt. Their freshwater may have originated from ice-age periods or possibly through connections with onshore aquifers, but not through current precipitation.
• Statement 3 is correct: Offshore aquifers are significant as untapped freshwater reserves that can help mitigate global freshwater scarcity, which is worsening due to climate change, pollution, and rising demand.
• Therefore, option B is the correct answer.

UPSC PYQ

Q.    With reference to ‘Water Credit’, consider the following statements: (2021)

1. It puts microfinance tools to work in the water and sanitation sector.
2. It is a global initiative launched under the aegis of the World Health Organization and the World Bank.
3. It aims to enable the poor people to meet their water needs without depending on subsidies.

Which of the statements given above are correct? 

(a) 1 and 2 only

(b) 2 and 3 only

(c) 1 and 3 only

(d) 1, 2 and 3

Ans: (c)