WATER CYCLE
1. Context
Climate change has been “wreaking havoc” on Earth’s water cycle by disrupting how water circulates between the ground, oceans and atmosphere, according to a new report. This has led to extreme precipitation, ferocious floods and droughts, which affected billions of people across the world in 2024.
2. What is a Water Cycle?
- The freshwater cycle, also known as the hydrological cycle, is the continuous movement and recycling of freshwater within the Earth's atmosphere, surface, and underground systems. It ensures that water is distributed across various ecosystems and supports life on Earth
- The water cycle refers to the continuous circulation of water in its three states—solid, liquid, and gas—on the Earth's surface, beneath it, and in the atmosphere.
- The cycle is primarily driven by solar energy and temperature changes. For example, water from surfaces such as land or bodies of water turns into water vapor through evaporation.
- Plants also play a role by absorbing water from the soil and releasing it into the atmosphere as water vapor through transpiration.
- This vapor eventually condenses to form clouds, which later release water back to Earth as precipitation, such as rain or snow.
- Once precipitation occurs, water can accumulate in ice caps, oceans, lakes, rivers, or glaciers, be absorbed by plants, or infiltrate the soil and move deeper underground. The process then repeats itself
3. 2024 Global Water Monitor Report highlights
The 2024 Global Water Monitor Report highlights significant disruptions in the global water cycle due to escalating climate extremes.
The report, ‘2024 Global Water Monitor Report’, was produced by an international team of researchers from universities in Australia, Saudi Arabia, China, Germany, and elsewhere. For their analysis, the researchers used data from ground stations and satellites to access water variables such as soil moisture, rainfall etc
Key findings from the report include:
- Record-Breaking Temperatures: The year 2024 experienced unprecedented global temperatures, intensifying the water cycle and leading to severe weather events
- Increased Water-Related Disasters: There was a notable rise in the frequency and severity of water-related disasters, including flash floods, river floods, droughts, tropical cyclones, and landslides. These events resulted in over 8,700 fatalities, displaced 40 million people, and caused economic losses exceeding US $550 billion
- Impact of Climate Change: The report underscores that climate change is exacerbating water-related disasters. Rising temperatures, driven by fossil fuel consumption, are intensifying monsoons, cyclones, and other storm systems, leading to increased rainfall intensity and flooding
- Terrestrial Water Storage Variations: Dry regions worldwide continued to experience low terrestrial water storage levels. Conversely, areas in western, central, and eastern Africa saw significant increases in water storage
- Call to Action: The findings emphasize the urgent need for global leaders to prioritize addressing the water crisis. The report calls for transformative changes in water consumption practices, substantial investments in infrastructure, and the implementation of appropriate water pricing mechanisms to mitigate the escalating crisis
4. How is climate change impacting the water cycle?
- Climate change is profoundly altering the water cycle, intensifying its processes and causing significant disruptions to natural water patterns worldwide. These changes are manifesting in various ways, leading to more extreme and unpredictable weather events that directly impact ecosystems, water availability, and human livelihoods.
- One of the most noticeable effects of climate change is the increase in global temperatures, which accelerates evaporation. As the planet warms, water from oceans, rivers, lakes, and soil evaporates at a faster rate.
- This results in higher levels of moisture in the atmosphere, which can fuel heavier and more intense precipitation events. Consequently, regions already prone to rainfall may experience severe flooding due to this intensified cycle.
- At the same time, the warming climate is causing glaciers, ice caps, and snowpacks to melt more rapidly. These frozen reserves of freshwater are critical for many regions, as they provide water for agriculture, drinking, and hydroelectric power during warmer months.
- As these ice reserves diminish, not only does this threaten seasonal water availability, but it also contributes to rising sea levels. This, in turn, leads to saltwater intrusion into freshwater aquifers, particularly in coastal areas, further reducing the availability of drinkable water.
- In other parts of the world, climate change is leading to prolonged periods of drought. High temperatures and reduced rainfall are intensifying dry conditions, particularly in arid and semi-arid regions.
- These droughts disrupt agriculture, deplete drinking water supplies, and contribute to desertification, where fertile lands gradually transform into barren deserts. Such conditions are made worse by the over-extraction of groundwater during droughts, as aquifers are unable to recharge adequately due to the lack of consistent precipitation.
- River systems are also undergoing significant changes. In some areas, reduced rainfall and increased evaporation are leading to lower river flows, while in others, glacial melt and heavy rains are causing excessive flows and frequent flooding. These altered patterns disrupt ecosystems that rely on consistent water availability and create challenges for human infrastructure, such as dams and irrigation systems.
- Moreover, the warming atmosphere can hold more water vapor, which intensifies the power of storms and cyclones. As a result, extreme weather events like hurricanes, typhoons, and monsoons are becoming more severe, leading to catastrophic damage in affected regions. These intensified storms also create feedback loops, where the water cycle's acceleration perpetuates even more extreme conditions.
- In essence, climate change is amplifying the natural variability of the water cycle. It is making wet regions wetter, dry regions drier, and weather patterns less predictable. This imbalance has far-reaching consequences, highlighting the urgent need for adaptation strategies, sustainable water management, and global efforts to mitigate climate change’s effects.
- Protecting water resources and ensuring their equitable distribution are critical to safeguarding the well-being of both people and ecosystems in the face of a rapidly changing climate
For Prelims: General issues on Environmental ecology, Bio-diversity and Climate Change – that do not require subject specialization
For Mains: General Studies III: Conservation, environmental pollution and degradation, environmental impact assessment
|
Source: Indianexpress