Context
More than half of the world’s large lakes and reservoirs have seen a reduction in size since the early 1990s, according to a recent research. Nearly 2,000 big lakes were examined as part of the study using satellite observations, climate models, and hydrological models.
Relevance:
GS Paper-3: Biodiversity and Environment
Mains Question
Examine critically how climate change has affected the disappearance of big lakes and reservoirs. Analyse the value of sustainable human use in resolving this problem. (250 Words).
Info
- Due to greenhouse gas emissions, lakes around the world will suffer a temperature change of up to 6.7°C by 2080.
- The Caspian Sea is notable for being the largest lake in the world.
- Chilika Lake was recognised as the first wetland of international significance in India in 1981.
- The Wular Lake in Jammu and Kashmir, India, bears the title of being the largest freshwater lake in the nation.
- The largest saltwater lake in India is Chilika Lake, which is found in the state of Odisha. Udaipur is known as the “City of Lakes” in India.
Key Findings:
- Over 50% decline: The study discovered that the water levels of more than half of the world’s large lakes and reservoirs had significantly decreased since the early 1990s. The availability and sustainability of water are severely threatened by this reduction.
- Impact of climate change: The fundamental cause of the reduction in these water bodies has been identified as climate change. The volume of lakes and reservoirs is declining as a result of increasing temperatures and shifting rainfall patterns.
- Human consumption: A big cause in the reduction is unsustainable human usage of water resources. Excessive extraction for home, industrial, and agricultural uses depletes water supplies, aggravating the issue.
- Modified rainfall and run-off: The replenishment of lakes and reservoirs is impacted by variations in rainfall patterns and increased run-off. Water levels decline as a result of decreased rainfall and increasing evaporation rates, which reduce the amount of water entering the system.
- Sedimentation: Lakes and reservoirs lose some of their ability to contain water as a result of the buildup of silt and other materials. The decrease in water levels is further exacerbated by this process.
- For nearly three decades, water has been lost from significant freshwater sources including the Caspian Sea and Lake Titicaca at a cumulative pace of around 22 mega tonnes per year.
- Positive Changes: The water levels in about 25% of the lakes under study have risen, frequently as a result of the construction of dams in distant regions like the Inner Tibetan Plateau.
Large Lakes and Reservoirs and Climate Change:
- Increased Evapotranspiration: o As temperatures rise, there is an increase in evapotranspiration, which is the total loss of water from plants and land surfaces.
- The water supply in lakes and reservoirs is further depleted as a result of this higher evapotranspiration rate.
- Melting glaciers and decreased snowfall: Mountainous regions are affected by climate change, which causes glaciers to melt and less snow to fall.
- These changes have an effect on the flow of freshwater into lakes and reservoirs, especially those that depend on snowmelt or glacier meltwater.
- Modified hydrological cycles: Climate change alters the time and length of the wet and dry seasons, among other aspects of the hydrological cycle.
- These changes have an impact on the water’s inflow and outflow, aggravating the depletion of sizable lakes and reservoirs.
- More frequent and severe extreme weather events: Droughts, heatwaves, and severe storms are just a few examples of the extreme weather events that are becoming more often as a result of climate change.
- These occurrences could result in a quick loss of water due to evaporation, increased runoff, or infrastructural damage, which would disrupt the overall water balance in lakes and reservoirs.
- Modifying rainfall patterns: Rainfall is distributed unevenly due to climate change.
- Changes in the timing and intensity of rainfall events or decreased precipitation in some locations have an effect on the amount of water entering lakes and reservoirs.
- Leads to a decline in water levels and a reduction in replenishment in the affected water bodies.
- Lake shrinkage and water scarcity are more likely to occur in areas with less rainfall.
Water scarcity:
- The dwindling of major lakes and reservoirs has serious ramifications for the world’s water supply.
- 0 Freshwater shortages affect a number of industries, including agriculture, energy, and human consumption.
- It makes the problem of water scarcity worse, which causes social unrest and economic problems.
- Food security: Irrigation in agriculture heavily depends on water supplies.
- As lakes and reservoirs get smaller, there is less water available for farming, which affects crop yields, food production, and food security.
- As a result, food shortages and price increases may occur.
- Energy production: The water supply for many hydroelectric plants is sourced from sizable lakes and reservoirs.
- Hydropower generation is impacted by the drop in water levels, which could have an influence on energy prices by causing energy shortages and a greater reliance on alternative energy sources.
- Disruption of ecosystems: Numerous ecosystems are supported by large lakes and reservoirs, and the extinction of these ecosystems poses a threat to aquatic life.
- It throws off the ecological equilibrium, which has an impact on ecosystem biodiversity and overall health.
- Socioeconomic effects: o Human populations are immediately impacted by the shrinkage of lakes and reservoirs. Communities that depend on these bodies of water for agriculture, drinking water, and their way of life suffer water shortages, increasing competition, and even migration.
- This presents serious socio-economic difficulties, especially in areas that rely largely on these water sources.
The importance of sustainable human use in solving the problem
- Reducing the demand for water: Unsustainable water use habits are a factor in the depletion of lakes and reservoirs.
- Excessive water extraction for domestic, industrial, and agricultural uses puts a strain on water supplies.
- By encouraging sustainable human usage, we can lessen the demand for water and ease the strain on these delicate water sources.
- Water management techniques that are effective include: o Putting water conservation measures in place to maximise water utilisation.
- Using prudent irrigation methods to reduce water waste.
- Water recycling and reuse to increase effectiveness.
- Reducing the amount of dangerous compounds introduced into lakes and reservoirs.
- Reducing pollution from untreated wastewater, agricultural runoff, and industrial discharge.
- The implementation of pollution prevention and wastewater treatment procedures.
- Long-term sustainability: o Sustainable human use practises guarantee the lakes’ and reservoirs’ long-term vitality.
- Balancing water extraction with these water bodies’ inherent capability for replenishing.
- Aiming to conserve the biodiversity and health of ecosystems by promoting responsible water management practises.
- The study’s findings highlight the urgent need for strategies to mitigate climate change and manage water resources sustainably.
- For global water security, food production, energy generation, and the welfare of human populations, it is imperative to address the reasons causing the loss of huge lakes and reservoirs.
- To reduce the effects and protect the world’s water supplies, effective regulations, conservation initiatives, and international cooperation are required.
