Geography: August 2024 UPSC Current Affairs | Current Affairs & Hindu Analysis: Daily, Weekly & Monthly PDF Download

Climate Change Impacts on Panama Canal Operations

Why in News?

The Panama Canal, a vital global shipping route, is encountering serious difficulties due to extended drought conditions intensified by climate change. This has resulted in decreased water levels in Lake Gatun, sparking discussions on sustainable long-term solutions to maintain the canal's operations.

What is the Impact of Climate Change on the Panama Canal?

Drought and Reduced Passage of Ships:

• The Panama Canal has been undergoing a prolonged drought that commenced in early 2023.
• Rainfall in October 2023 was recorded at 43% below average, marking it as the driest October since the 1950s.
• Ship traffic through the canal fell to as few as 22 vessels per day in December 2023, significantly lower than the usual 36 to 38 ships, due to diminished water levels in Lake Gatun.

Restriction on Size of Ships:

• The lowered water levels impose restrictions on the size of vessels that can transit the canal, as larger ships face a greater risk of grounding in shallower waters.
• Heavier vessels require a more substantial volume of lake water for elevation in the locks.

Effect on Global Trade:

• The Panama Canal handles approximately 5% of global shipping, meaning disruptions in this area adversely impact the international supply chain.
• Consequences include delayed shipments, increased fuel consumption, and potential GDP losses.
• Ships are forced to take alternative routes, which involve longer travel distances to the southern points of South America.

What are Key Facts about the Panama Canal?

About Panama Canal:

• The Panama Canal is an artificial waterway stretching 82 kilometers, linking the Atlantic Ocean to the Pacific Ocean.
• It traverses the Isthmus of Panama and serves as a crucial conduit for maritime trade.
• The canal saves around 12,600 km in travel between New York and San Francisco.
• The first ship navigated through the Panama Canal on 15 August 1914.

Functioning of Panama Canal:

• The canal operates as a sophisticated, highly engineered system employing locks and elevators to transport ships from one ocean to another.
• This operation is necessary because the Pacific and Atlantic Oceans are at different elevations, with the Pacific being slightly higher.
• When a ship enters the canal from the Atlantic, it must ascend to reach the Pacific, facilitated by a lock system that raises and lowers vessels to the appropriate sea level at both ends of the canal.
• Locks function by either flooding (to elevate) or draining (to lower), acting as water elevators.
• The system features a total of 12 locks, which are supported by artificial lakes and channels.

Mains Question

Q: Discuss the impact of Climate Change on water channels? How canals are inevitable for the smooth flow of global trade?

Kosi-Mechi River Linking Project Faces Opposition in Bihar'

Why in News?

The Kosi-Mechi River Linking Project, part of India's ambitious National Perspective Plan (NPP) for interlinking rivers, has sparked controversy. Flood victims in Bihar have protested against its implementation. Although the project aims to enhance irrigation in the region, locals argue that it does not adequately address the pressing issue of flood control, which affects them each year.

What are the Key Facts About the Kosi-Mechi River Linking Project?

About:

• The project seeks to connect the Kosi River with the Mechi River, a tributary of the Mahananda River, impacting areas in Bihar and Nepal.
• It aims to provide irrigation to 4.74 lakh hectares (2.99 lakh hectares in Bihar) and supply 24 million cubic meters (MCM) of domestic and industrial water.
• Upon completion, it is expected to release an additional 5,247 cubic feet per second (cusecs) of water from the Kosi barrage.
• The project is managed by the National Water Development Agency (NWDA) under the Union Ministry of Jal Shakti (Water Resources).

Concerns:

• The primary design of the project focuses on irrigation, targeting 215,000 hectares of agricultural land in the Mahananda river basin during the Kharif season.
• Despite government claims, it lacks a significant flood control component, raising concerns for the flood-prone region.
• The additional water release of 5,247 cusecs is minimal compared to the barrage's capacity of 900,000 cusecs.
• Locals contend that this small increase in water flow will not effectively mitigate the annual flooding that devastates their communities.
• Flooding and land erosion have caused extensive damage to homes and crops, impacting local livelihoods.

What are the Key Facts About Kosi River and Mechi River?

Kosi River:

• Known as the "Sorrow of Bihar," the Kosi River originates over 7,000 meters above sea level in the Himalayas, within the catchment area of Mount Everest and Kanchenjunga.
• It flows through China, Nepal, and India, entering India near Hanuman Nagar and merging with the Ganga River near Kursela in Katihar district, Bihar.
• The Kosi River is formed by the confluence of three main streams: the Sun Kosi, Arun Kosi, and Tamur Kosi.
• Notably, the Kosi is known for its tendency to shift its course westward, having moved 112 km over the past 200 years, leading to devastation in agricultural lands in districts like Darbhanga, Saharsa, and Purnea.
• It has several important tributaries, including the Trijunga, Bhutahi Balan, Kamla Balan, and Bagmati, which join the Kosi during its journey through the plains.

Mechi River:

• A trans-boundary river flowing through Nepal and India, Mechi is a tributary of the Mahananda River.
• This perennial river originates in the inner valley of the Himalayas in the Mahabharat range of hills in Nepal and flows through Bihar to join the Mahananda in Kishanganj district.

What is the National Perspective Plan for Interlinking Rivers?

The National Perspective Plan (NPP) was formulated in 1980 by the Ministry of Irrigation (now Ministry of Jal Shakti) to develop water resources through inter-basin transfers.

Components:

• The plan is divided into two main components: the Himalayan Rivers Development Component and the Peninsular Rivers Development Component.

Projects Identified:

• Thirty link projects have been identified, with 16 under the Peninsular Component and 14 under the Himalayan Component.

Key Projects Under Peninsular Component:

• Mahanadi-Godavari Links, Godavari-Krishna Links, Par-Tapi-Narmada Link, and the Ken-Betwa Link (the first project under the NPP to begin implementation).

Key Projects Under Himalayan Component:

• Kosi-Ghaghra Link, Ganga (Farakka)-Damodar-Subernarekha Link, and Kosi-Mechi Link.

Significance:

• The NPP aims to manage flood risks in the Ganga-Brahmaputra-Meghna basin.
• It seeks to address water shortages in western and peninsular states such as Rajasthan, Gujarat, Andhra Pradesh, Karnataka, and Tamil Nadu.
• The plan aims to improve irrigation in water-scarce regions, boosting agricultural productivity and enhancing food security, potentially doubling farmers' incomes.
• It will facilitate the development of infrastructure for freight movement via environmentally friendly inland waterways.
• The NPP is designed to utilize surface water to alleviate groundwater depletion and reduce freshwater flow into the sea.

Challenges:

• Comprehensive feasibility studies assessing economic, social, and ecological impacts are often incomplete, leading to uncertainty about project effectiveness.
• Inadequate data can result in potential unintended consequences.
• Water being a state subject complicates agreements on water sharing, leading to disputes like those between Kerala and Tamil Nadu.
• Large-scale water transfers can exacerbate flooding, disrupt local ecosystems, and cause water logging and increased salinity in agricultural lands, adversely affecting soil quality and crop yields.
• The extensive financial burden for construction, maintenance, and operation of dams, canals, and infrastructure is significant.
• Climate change may alter rainfall patterns, impacting water availability and distribution, potentially undermining the project's benefits.

Way Forward

• Develop a comprehensive plan for floodplain zoning, restricting settlements and critical infrastructure in high-risk areas.
• Encourage flood-resistant housing and cropping patterns in designated zones.
• Invest in strengthening embankments along the Kosi River to prevent breaches and reduce flooding.
• Create a clear mechanism to ensure equitable distribution of project benefits.
• Flood-prone areas should receive significant investments in flood control measures, while water-scarce regions benefit from improved irrigation infrastructure.
• Considering the challenges of the Interlinking of Rivers plan, adopting the National Waterways Project (NWP) offers a promising alternative.
• The NWP utilizes excess floodwaters currently flowing into the sea, avoiding state disputes over water sharing and providing a more cost-effective solution for irrigation and power generation.

Mains Question

Q: Discuss the objectives and expected benefits of the Kosi-Mechi River Linking Project. How does it align with the broader goals of the National Perspective Plan for Interlinking Rivers?

Unprecedented Deep-Winter Heatwave Strikes Antarctica

Why in news?

Antarctica is currently facing its second severe winter heatwave within a span of two years, with ground temperatures averaging 10°C above the normal levels since mid-July. On certain days, temperatures have spiked as much as 28°C higher than usual.

Status of Temperatures in East Antarctica

• Current Temperature Levels: The temperatures in East Antarctica range between -25°C and -30°C.
• Typical Winter Temperatures: Normally, deep-winter temperatures in this region fluctuate between -50°C and -60°C.

About Heat Wave

• Heat Wave Definition: A heat wave is defined as a period of excessively high temperatures that surpass the normal maximum temperatures for the summer season.
• Timing: Heat waves typically occur from March to June and can occasionally extend into July.
• Trends: Due to global climate change, heat waves are becoming more frequent and intense, characterized by higher peak temperatures and prolonged durations.

Reasons for the Heatwave in Antarctica

• Weakening of the Polar Vortex: The primary factor contributing to the heatwave is the weakening of the polar vortex, which is a band of cold air and low-pressure systems circulating around the Earth’s poles in the stratosphere. This vortex usually traps cold air, preventing warm air from entering. However, this year, large-scale atmospheric waves disrupted the vortex, allowing warm air to infiltrate the region.
• Reduced Antarctic Sea Ice: Sea ice plays a crucial role in regulating temperatures in polar regions by reflecting sunlight back into space and serving as a barrier between frigid air and warmer water below. A significant reduction in the extent of Antarctic sea ice has contributed to the heatwave, as less sea ice means more sunlight is absorbed, resulting in higher temperatures.
• Accelerated Warming in Antarctica: Antarctica is warming at a rate of 0.22°C to 0.32°C per decade, which is nearly double the global average due to climate change. This rapid warming increases the likelihood of extreme weather events like heat waves, exacerbating the impact of other contributing factors.

Consequences of Antarctica’s Heatwave

• Ecosystem Disruption: The heatwave threatens Antarctic ecosystems, impacting species reliant on cold, stable conditions, potentially leading to alterations in the food chain and affecting global biodiversity.
• Habitat Loss: As ice continues to melt, habitats for cold-adapted species such as penguins and seals may diminish, risking their populations.
• Historical Ice Loss and Heat Wave Impact:

• Antarctic Ice Sheet Impact: The ongoing heatwave may accelerate the loss of the Antarctic Ice Sheet, which is crucial for global ice reserves. This ice sheet is essential for maintaining global ocean circulation, which distributes heat, carbon, nutrients, and freshwater.
• Global Sea Level Threat: If melted, the Antarctic Ice Sheet, which contains over 60% of the world's freshwater, could significantly elevate global sea levels, displacing millions of people living in coastal areas.
• Feedback Loops and Further Warming:
  • Albedo Effect: The reduction of ice decreases the Earth's albedo, or its ability to reflect sunlight. Reduced ice cover leads to increased sunlight absorption by the ocean, resulting in additional warming and accelerated ice melt.
  • Potential Runaway Warming: This process may initiate a feedback loop where warming causes more ice melt, which in turn leads to further warming, potentially pushing the Antarctic climate system towards irreversible changes.
• Global Climate Implications:
  • Extreme Weather: Changing conditions in Antarctica could affect global weather patterns, leading to an increase in extreme weather events such as heatwaves, storms, and floods in various regions worldwide.
  • Impact on Global Carbon Cycle: Disruption of the ocean circulation system may influence the global carbon cycle, potentially resulting in higher levels of carbon dioxide in the atmosphere and worsening global warming.
  • Slowing Circulation: The melting ice is decreasing surface water salinity and density, which is slowing down ocean circulation and affecting climate regulation.

Significance of Antarctica

• Climate Regulation: The Antarctic ice sheet reflects substantial solar energy, helping to control the Earth's temperature.
• Ocean Circulation: It plays a key role in ocean circulation, which influences climate patterns globally.
• Freshwater Storage: The Antarctic ice sheet is the largest reservoir of freshwater on Earth, holding approximately 60 meters of sea level equivalent.
• Biodiversity: Despite harsh climatic conditions, Antarctica supports a variety of wildlife, including penguins, seals, and various seabird species.
• Scientific Research: Ice cores from Antarctica provide valuable data on the Earth’s climate history spanning millions of years, serving as a natural laboratory for studying life in extreme environments and understanding entire ecosystems.

India’s Endeavour at Antarctica

• Initiation and Early Years: The Indian Antarctic Programme commenced in 1981 with its first expedition. India became a Consultative Member of the Antarctic Treaty in 1983.
• Research Stations:
  • Dakshin Gangotri: Established in 1984, this was India’s first research base, which now operates as a supply depot.
  • Maitri: This is India’s second permanent research station, established in 1989.
  • Bharati: The newest research base, commissioned in 2015.
• Scientific Expeditions: India has conducted 43 scientific expeditions focusing on various fields, including atmospheric science, biology, earth sciences, chemistry, and medical sciences. The 40th expedition in 2021 marked four decades of India’s contributions to Antarctic research.
• International Collaboration: The ongoing 43rd expedition, launched in 2023, emphasizes climate change research and promotes international scientific collaboration.

Criteria for Heat Waves

• General Criteria:
  • Plains: A heat wave is declared when the maximum temperature reaches at least 40°C.
  • Hilly Regions: A heat wave is declared when the maximum temperature reaches at least 30°C.
• Conditions Based on Normal Maximum Temperature:
  • Normal Maximum Temperature ≤ 40°C: An increase of 5°C to 6°C above the normal temperature indicates a heat wave.
  • Severe Heat Wave: An increase of 7°C or more above the normal temperature signifies a severe heat wave.
  • Normal Maximum Temperature > 40°C: An increase of 4°C to 5°C above normal temperature indicates a heat wave.
  • Increase of 6°C or more: This indicates an even more severe heat wave.
• Additional Criterion:
  • Actual Maximum Temperature: If the maximum temperature reaches 45°C or higher, a heat wave is declared, regardless of the normal maximum temperature.

Dark Oxygen

Overview

Scientists have recently identified a peculiar phenomenon named "dark oxygen" found in the deep ocean.

About

This oxygen is produced in total darkness, at depths thousands of feet beneath the ocean surface.

Why is the discovery important?

• Previously, it was believed that oxygen could only be produced via photosynthesis, a process reliant on sunlight.
• Primary contributors to oxygen production in oceans include oceanic plankton, plants, algae, and certain bacteria, all of which perform photosynthesis.
• It was assumed that oxygen generation at such profound depths was impossible due to insufficient sunlight for photosynthetic organisms.
• In this unique case, oxygen is not generated by plants but rather from polymetallic nodules, which resemble lumps of coal.
• These nodules consist of metals such as manganese, iron, cobalt, nickel, copper, and lithium, and can produce oxygen through electrochemical reactions even without light.
• This process involves splitting water (H2O) molecules into hydrogen and oxygen.

Key Facts about Polymetallic Nodules:

• Polymetallic nodules, often referred to as manganese nodules, are small, rounded formations located on the deep ocean floor.
• These nodules are made up of a blend of metals and minerals, including manganese, iron, nickel, copper, cobalt, and trace amounts of other valuable elements such as platinum and rare earth elements.
• The formation of these nodules occurs gradually over millions of years, developing concentric layers around a central core, which can be a shell fragment, shark tooth, or basaltic rock piece.
• The layers primarily consist of manganese and iron oxides, with other metals being deposited alongside them.
• These metals are crucial for the manufacturing of lithium-ion batteries utilized in electric vehicles, mobile phones, wind turbines, and solar panels.
• Locations rich in polymetallic nodules include the north-central Pacific Ocean, southeastern Pacific Ocean, and northern Indian Ocean.
• It is estimated that the Clarion-Clipperton Zone may contain sufficient polymetallic nodules to meet global energy needs for decades.

India Names Underwater Structures in the Indian Ocean

Why in news?

Recently, three underwater structures were designated as Ashoka, Chandragupt, and Kalpataru, highlighting India's expanding role in marine science and its dedication to exploring the Indian Ocean. This naming was suggested by India and endorsed by the International Hydrographic Organisation (IHO) and UNESCO's Intergovernmental Oceanographic Commission (IOC).

What are the Key Facts About the Underwater Structures?

• Background and Significance: The identification of these underwater structures is part of the Indian Southern Ocean Research Programme, which began in 2004, with the National Centre for Polar and Ocean Research (NCPOR) as the lead agency. The program's objective is to investigate various elements, including bio-geochemistry, biodiversity, and hydrodynamics.
• Total Structures: In total, seven structures have been named, including the recent additions in the Indian Ocean, primarily after Indian scientists or based on names proposed by India.
• Previously Named Structures:
  • Raman Ridge: Accepted in 1992, it was discovered in 1951 by a US oil vessel and named in honor of physicist Sir CV Raman, a Nobel Laureate.
  • Panikkar Seamount: Recognized in 1993, discovered in 1992 by the Indian research vessel Sagar Kanya, named after renowned oceanographer NK Panikkar.
  • Sagar Kanya Seamount: Accepted in 1991, named after the research vessel Sagar Kanya following its successful 22nd cruise in 1986.
  • DN Wadia Guyot: Named in 1993 after geologist DN Wadia, this underwater volcanic mountain was discovered in 1992 by Sagar Kanya.
• Recently Named Structures:
  • Ashoka Seamount: Discovered in 2012, this oval-shaped structure spans approximately 180 sq km and was identified using the Russian vessel Akademik Nikolay Strakhov.
  • Kalpataru Ridge: Also discovered in 2012, this elongated ridge covers an area of 430 sq km and is believed to be vital in supporting marine biodiversity by providing habitats and food for various species.
  • Chandragupt Ridge: Identified in 2020, this ridge extends over 675 sq km and was discovered by the Indian research vessel MGS Sagar.

What are the Different Underwater Structures/Relief on the Ocean Floor?

• About: The ocean floor, or seabed, constitutes the base of the water that covers over 70% of the Earth's surface, containing resources like phosphorus, gold, silver, copper, zinc, and nickel. The main factors shaping ocean relief include tectonic plate interactions and various geological processes such as erosion, deposition, and volcanic activity.
• Zones of Ocean Floor:
  • Continental Shelf: This is the shallowest and widest segment of the ocean floor, extending from the coast to the continental slope where it drops steeply. It is abundant in marine life and resources, including fish, oil, and gas.
  • Continental Slope: A steep area connecting the continental shelf to the abyssal plain, characterized by deep canyons and valleys formed by underwater landslides and sediment rivers. It is home to deep-sea creatures, such as octopuses and anglerfish.
  • Continental Rise: Composed of thick layers of continental material that accumulate between the continental slope and the abyssal plain, formed through sediment movement and settling from above.
  • Abyssal Plain: The flattest part of the ocean floor, lying between 4,000 and 6,000 meters below sea level, covered by fine sediment. It hosts some of the most peculiar marine animals, like giant tube worms and vampire squids.
  • Oceanic Deeps or Trenches: These are the deepest ocean regions, featuring steep-sided, narrow basins that can reach 3-5 km deeper than the surrounding areas, often associated with active volcanoes and earthquakes, making them crucial for studying plate movements.
• Minor Relief Features of Ocean Floor:
  • Submarine Canyons: Significant geological features on continental margins, acting as connections between the upper continental shelf. They are deep, narrow valleys with steep slopes.
  • Mid Oceanic Ridges: Located at diverging plate boundaries, these ridges are formed by magma filling gaps as tectonic plates separate, creating new oceanic crust.
  • Seamounts and Guyots: Seamounts are underwater mountains formed by volcanic activity, rising significantly from the ocean floor, while flat-topped seamounts that have submerged are termed guyots.
  • Atoll: A ring-shaped formation of coral reefs surrounding a lagoon, typically developing around seamounts, with low islands in tropical oceans.

Mains Question

Q: What are the different types of oceanic relief features found on the ocean floor?

Pyrocumulonimbus Clouds

Why in news?

Overview:

• Rising temperatures globally are contributing to more frequent and intense wildfires.
• These wildfires are linked to the increased formation of pyrocumulonimbus clouds.

What is a Cumulonimbus Cloud (Cb)?

A cumulonimbus cloud is a heavy, dense cloud with significant vertical development.

It typically resembles a towering mountain and is associated with:

• Heavy precipitation
• Lightning
• Thunder
• Commonly referred to as "thunderclouds."
• It is the only cloud type capable of producing hail, thunder, and lightning.
• The base of a cumulonimbus cloud is often flat with a dark, wall-like feature beneath it.
• Altitude ranges from 3 km to occasionally more than 15 km (10,000 to 50,000 ft).

Formation requires three conditions:

• A deep layer of unstable air
• The air must be warm and moist
• A trigger mechanism to cause the rise of warm, moist air
• Heating can occur due to:
• Warm air near the surface
• Orographic uplift (air forced upwards by terrain)
• A cold front pushing the air upwards

About Pyrocumulonimbus Clouds:

• Pyrocumulonimbus clouds are thunderclouds formed by intense heat from the Earth's surface.
• These clouds develop similarly to cumulonimbus clouds but are driven by:
  • Heat generated from large wildfires or volcanic eruptions.
• The prefix "pyro," meaning fire in Greek, indicates their fiery origin.
• These clouds appear darker than typical clouds due to the presence of smoke and ash.
• Pyrocumulonimbus clouds can trap various aerosol pollutants (like smoke and ash) in the stratosphere.
• They can also generate lightning strikes, which have the potential to ignite new fires.

Impact of Climate Change on Earth’s Rotational Dynamics

Why in news?

Recent research highlights that melting polar ice caps due to climate change are causing the Earth to spin more slowly, leading to minute changes in the duration of a day. This phenomenon, while not immediately noticeable in daily lives, could have significant implications for technology reliant on precise timekeeping.

How is Climate Change Affecting Earth's Rotation?

Melting Ice Caps:

• The melting of polar ice sheets leads to water flowing towards the equator, which increases the Earth's oblateness and moment of inertia.
• Studies indicate that over the past two decades, the Earth's rotation has slowed by approximately 1.3 milliseconds per century.
• The principle of angular momentum explains this effect: as polar ice melts and shifts towards the equator, the Earth's moment of inertia (mass distribution near the equator) rises, causing a decrease in rotational speed to conserve angular momentum.
• If high emission scenarios continue, projections suggest this slowdown could increase to 2.6 milliseconds per century, making climate change a major factor in the Earth's rotational slowdown.

Axis Shifts:

• The melting ice also affects the Earth's axis of rotation, leading to slight but measurable shifts.
• This small movement highlights how climate change is impacting essential Earth processes.
• The Earth's rotational axis is tilted in relation to its geographic axis, causing a phenomenon known as the Chandler wobble, which can influence rotational timing and stability.

What are the Implications of Slowdown of Earth's Rotation?

Leap Seconds:

• The Earth's rotation impacts the need for leap seconds to synchronize atomic clocks with solar time.
• A slowdown in rotation may require additional leap seconds, affecting systems that depend on precise timekeeping.
• This adjustment could lead to issues in technology, such as network outages or inaccuracies in data timestamps.

Global Positioning Systems (GPS):

• GPS satellites depend on precise time measurements, and variations in the Earth's rotation can affect their accuracy.
• This could result in minor errors in navigation and location services.

Sea Level Rise:

• The redistribution of mass from melting polar ice is contributing to changes in sea levels.
• A slowdown in the Earth's rotation can impact ocean currents, including the Global Mean Ocean Circulation (GMOC), which may influence regional climate patterns and exacerbate sea level rise issues.
• GMOC is crucial as it moves water, heat, and nutrients across the world's oceans, playing a key role in regulating the global climate.

Earthquakes and Volcanic Activity:

• Although indirectly, changes in the Earth's rotation and mass distribution can affect tectonic processes.
• Variations in rotation might alter stress distribution in the Earth's crust, potentially influencing seismic and volcanic activity.

Climate Change Evidence:

This phenomenon serves as a stark reminder of the broad impact of climate change, affecting not only weather patterns and sea levels but also the fundamental mechanics of our planet's rotation.

Mains Question:

Q: Discuss the implications of climate change on Earth's rotational dynamics.

Antarctica’s Deep Winter Heatwaves

Why in News?

Recently, Antarctica has been experiencing a significant deep-winter heatwave, marking the second instance of record-breaking temperatures in two years. Ground temperatures have risen by an average of 10 degrees Celsius above normal since mid-July 2024, with some areas experiencing increases of up to 28 degrees Celsius.

What are the Causes of Deep-Winter Heat Waves in Antarctica?

Weakening of the Polar Vortex:

• The polar vortex is a large area of low pressure and cold air surrounding the poles.
• This system weakens in summer and strengthens in winter, allowing cold air to escape and warm air to descend.
• Recent higher temperatures and powerful atmospheric waves have disrupted this vortex, leading to increased temperatures in the region.

Reduction of Antarctic Sea Ice:

• Sea ice levels are historically low, reducing its ability to reflect solar energy and acting as a barrier between cold air and warmer waters.
• This loss contributes to the overall increase in global temperatures.

High Rate of Global Warming:

• Antarctica is warming at a rate nearly double that of the global average, estimated at 0.22 to 0.32 degrees Celsius per decade.
• The Intergovernmental Panel on Climate Change (IPCC) estimates that the region is warming at a rate of 0.14-0.18 degrees Celsius per decade, primarily driven by human-induced climate change.

Impact of the Southern Ocean:

• The Southern Ocean absorbs more heat due to reduced sea ice, creating a feedback loop that raises air temperatures over Antarctica.
• This increase in temperature heightens the risk of extreme weather events in the region.

What are the Consequences of Heat Waves in Antarctica?

Accelerated Ice Melt:

• Rising winter temperatures in Antarctica are causing a significant increase in ice mass loss, with a reported 280% increase compared to the 1980s and 1990s.
• In March 2022, a heat wave led to the collapse of an ice section approximately 1300 square kilometers in size, raising concerns about rising global sea levels.

Global Sea Level Rise:

• The Antarctic ice sheet, covering 98% of Antarctica, contains over 60% of the world's freshwater.
• A slight increase in sea levels could displace around 230 million people living within 3 feet of current high tide lines, threatening coastal cities and ecosystems.

Disruption of Ocean Circulation:

• The influx of freshwater from melting ice alters the salinity and density of ocean waters, slowing down global ocean circulation.
• A study in 2023 indicated that this slowdown weakens the ocean's ability to store and transport heat, carbon, and nutrients, which are crucial for climate regulation.

Ecosystem Disruption:

• Changes in temperature and ice loss disrupt local ecosystems, threatening species that depend on stable ice, such as polar bears and penguins.
• This disruption can lead to biodiversity loss and alter global food webs.

Feedback Loops:

• Melting ice reduces sunlight reflection (the albedo effect), increasing heat absorption by oceans and land, which accelerates further ice melt.
• This creates a feedback loop that exacerbates climate change.

Tectonic Events Changed the Course of Ganga

Why in news?

Recently, researchers conducted a study on the river channels in the Ganges delta, specifically in Bangladesh. They identified a paleochannel, an ancient river channel, which indicates that the Ganga experienced a sudden shift in its course approximately 2,500 years ago due to an earthquake.

How Earthquakes Impact the Course of a River Ganga?

• Earthquake Origin: The researchers suggested that the earthquake may have originated from the Indo-Burma mountain ranges or the Shillong hills, where the Indian and Eurasian tectonic plates converge.
• Impact: This discovery emphasizes that significant earthquakes can lead to major river avulsions, which are abrupt changes in the flow of rivers. Such events can result in catastrophic floods, particularly in densely populated areas like the Ganges-Meghna-Brahmaputra delta.

Earthquake Evidence

• Seismite Formation: Seismites are sedimentary layers altered by seismic activity. They occur when seismic waves compress a layer of saturated sand, causing it to break through overlying mud layers.
• Sand Dikes: Researchers discovered two large sand dikes about one kilometer east of the paleochannel. Sand dikes are created when earthquakes disrupt the riverbed, resulting in sediment flow due to liquefaction.
• Dating Techniques: Using optically stimulated luminescence (OSL) dating, researchers estimated the timing of the river avulsion and the formation of the sand dikes to around 2,500 years ago, indicating that the earthquake was responsible for the river’s shift.

Future Hazards and Recommendations

• Potential Impact: A similar earthquake today could affect areas housing up to 170 million people in India and Bangladesh.
• Increased Risk: Factors such as rapid land subsidence and rising sea levels due to climate change heighten the risk of future river avulsions.
• Future Research: There should be a focus on understanding the frequency of earthquakes that lead to river avulsions and enhancing earthquake prediction methods.
• Preparedness: Collaboration between India, Bangladesh, and Myanmar is essential for research, monitoring, and preparedness to reduce the risks associated with these natural disasters.

What are Key Facts About the Ganga River System?

• The Ganga originates as the Bhagirathi from the Gangotri Glacier in Uttarakhand, at an elevation of 3,892 meters.
• Numerous small streams contribute to the Ganga's headwaters, with significant ones including Alaknanda, Dhauliganga, Pindar, Mandakini, and Bhilangana.
• At Devprayag, where the Alaknanda meets the Bhagirathi, the river is named Ganga. It flows a total of 2,525 kilometers before reaching the Bay of Bengal.
• The Ganga is formed from six headstreams and their five confluences:

Confluence of

• Bhagirathi river and Alaknanda river - Rudraprayag
• Mandakini river and Alaknanda - Nandaprayag
• Nandakini river and Alaknanda - Karnaprayag
• Pindar river and Alaknanda - Vishnuprayag
• Dhauliganga river and Alaknanda - Dhauliganga

The Bhagirathi, regarded as the source stream, rises at the Gangotri Glacier's base at Gaumukh. It eventually flows into the Bay of Bengal.

Major Tributaries of the Ganga River

• Left Bank Tributaries: Ramganga, Gomti, Ghaghara, Gandak, Burhi Gandak, Koshi, Mahananda.
• Right Bank Tributaries: Yamuna, Tons, Karamnasa, Sone, Punpun, Falgu, Kiul, Chandan, Ajoy, Damodar, Rupnarayan.
• The Ganga exits the hills and enters the plains where it meets the Yamuna in Allahabad.
• Delta and Outflow: After traveling approximately 2,510 kilometers, the Ganga merges with the Brahmaputra River in Bangladesh, forming the Padma River. The Padma then joins the Meghna River and flows into the Bay of Bengal through the Meghna Estuary.

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