Geography - 1 | Current Affairs & Hindu Analysis: Daily, Weekly & Monthly - UPSC PDF Download

Cyclone Gabrielle

New Zealand has declared a National State of Emergency for just the third time in history as Cyclone Gabrielle causes wide spread flooding, landslides and huge ocean swells across the North Island.

• Origin: Gabrielle started late last week as a tropical cyclone in the Coral Sea and intensified very quickly to a category 3, fuelled by very warm oceans.
• Extra tropical transition (ET): The Cyclone Gabrielle has undergone a process called extra tropical transition, where a tropical cyclone moves out of the tropics to cooler waters, its characteristics began to change and interact with other weather factors that exist in the mid-latitudes.
  • Hybrid cyclones: When a cyclone undergoes ET, they are often termed as Hybrid cyclones as they exhibit characteristics of both tropical and extratropical cyclones.
  • What happens during the ET?
• During ET, the warm core of the tropical cyclone is replaced by a cold core as the system interacts with the colder environment.
• The energy source of the storm shifts from the latent heat of condensation in the tropical cyclone to the temperature contrasts in the extratropical environment.
• The cyclone also begins to take on characteristics of an extratropical cyclone, such as the development of frontal boundaries and a larger wind field.
  • Characteristics: Hybrid cyclones have a vertical structure showing features partially similar to both tropical cyclones and extratropical cyclones.
• In particular, they have a warm core in the lower part of the troposphere and a cold core in the upper part.
  • Impacts of ET: The impacts of ET can vary depending on the storm’s location, size, and intensity.
• In some cases, the transition can lead to a weakening of the storm and a reduction in the amount of rainfall.
• While in other cases, the storm can intensify and produce heavy rainfall and strong winds as an extratropical cyclone.

What are Cyclones?

• Cyclones are rapid inward air circulation around a low-pressure area whereas anti-cyclones are circulation of winds around a high-pressure area.
• Types: There are two types of cyclones.
  • Tropical cyclones (also called typhoon or hurricane, an intense circular storm that originates over warm tropical oceans).
  • Extra Tropical cyclones (also called temperate cyclones or middle latitude cyclones or Frontal cyclones or Wave Cyclones).

The Yellow River

Context

A recent study has noted that the Chinese practice of building embankments is one of the reasons to blame for the devastating floods occurring in the “Yellow river”. 

About Yellow River

• The Yellow River (Huang He) is the second longest river in China (after the Yangtze).
• It’s the fifth-longest river in the world.
• Source: The Bayankala Mountains on the Plateau of Tibet in western central China.
• Mouth: southern Bohai Sea
• Claims to fame: world’s muddiest major river, “China’s cradle (of civilization)”
• Provinces flowed through: Qinghai, Sichuan, Gansu, Ningxia, Inner Mongolia, Shaanxi, Shanxi, Henan, and Shandong
• Tributaries: Black River, White River, Tao River, Huangshui, Fen River, Luo River, Wei River.
• The name “Yellow River” comes from the huge amounts of “yellow” loess sediment it carries, which are eroded when it flows through the Loess Plateau.
• The Yellow River is not just an iconic river of China, but also the symbol of the Chinese spirit: bearing burdens (its sedimentation), adaptation (its course changes), and perseverance (its continual flow).
• Hukou Waterfall on it is the second-largest waterfall in China.
• Qinghai Lake on it is China’s biggest lake.

Zojila Pass and Razdan Pass Reopen After Short Winter Closure

About Zojila Pass

• Zojila Pass, also known as ‘The Mountain Pass of Blizzards’, is a strategic pass that connects Kashmir Valley to Ladakh.
• It is located on the Srinagar-Kargil-Leh highway (NH-1) at a height of 11,650 feet.
• The pass remains closed for almost half of the year due to heavy snowfall.
• History:
  • It was the site of the Indo-Pakistan War of 1947-48.
  • It was captured by militias aided by the Pakistan Army in 1848, with the ultimate aim of capturing Ladakh.
  • However, the pass itself was captured by the Indian Army on 1st November 1948 in an assault codenamed Operation Bison.

What is Zojila Tunnel?

• Location: It is an under-construction tunnel situated at an altitude of 11,578 ft (around 3,500 metres) on the Srinagar-Leh Highway in Jammu and Kashmir.
• The tunnel would provide all-weather connectivity between Srinagar and Leh on NH-1.
• Total Length: 14.15 km.
• It will be India’s longest road tunnel, and Asia’s longest bi-directional tunnel.
• It would be 9.5-meter wide and 7.57-meter high in the shape of a horseshoe.

International Day of Action for Rivers 2023

Context

Every year on March 14, the International Day of Action for Rivers (IDAR) is observed to promote awareness of the importance of the river systems on the planet earth.

• This year, the 25th anniversary of the day was observed. The day was earlier known as International Day against Dams, for Rivers, Water, and Life.

What are the Key Points Related to IDAR?

• Theme: Rights of Rivers.
  • It calls for the designation of rivers as a national treasure.
• History:
  • The participants of the First International Meeting of People Affected by Dams held in March 1997 in Curitiba Brazil adopted the International Day of Action Against Dams and For Rivers, Water, and Life.
  • 20 countries' representatives had decided that the International Day of Action would take place on 14 March Brazil's Day of Action Against Large Dams.
• Significance:
  • It demonstrates how crucial rivers are to sustaining human life.
    • Rivers and other freshwater environments are crucial sources of clean water for agriculture and drinking but are sadly being subjected to significant quantities of pollution and contamination by both the general people and industries.
  • The day tries to focus on the uneven access to clean water and the pollution occurring due to human activities. This is the reason behind the increase in the pollution of freshwater.

What are the Related Indian Initiatives?

• Namami Gange Programme: It is an Integrated Conservation Mission, approved as a ‘Flagship Programme’ by the Union Government in June 2014 to accomplish the twin objectives of effective abatement of pollution and conservation and rejuvenation of National River Ganga.
  • Ganga was declared as the ‘National River’ of India in 2008.
• Ganga Action Plan: It was the first River Action Plan that was taken up by the Ministry of Environment, Forest and Climate Change in 1985, to improve the water quality by the interception, diversion, and treatment of domestic sewage.
  • The National River Conservation Plan is an extension to the Ganga Action Plan.
• National River Conservation Plan (NRCP):
  • NRCP is the Centrally Sponsored Scheme implemented for abatement of pollution in identified stretches of rivers in the country, excluding those in Ganga basin, by providing financial and technical assistance to the States/Union Territories (UTs) on cost sharing basis.
• National River Rejuvenation Mechanism:
  • The National Green Tribunal (NGT) directed the Ministry of Jal Shakti to devise an appropriate National River Rejuvenation Mechanism for effective monitoring of steps to curb pollution and for rejuvenation of all polluted river stretches across the country.

Africa’s Rift Valleyand the Creation of a New Ocean Basin

Context

Scientists, in 2020, predicted a new ocean would be created as Africa gradually splits into two separate parts. 

• The division of the continent is connected to the East African Rift, which appeared in the desert of Ethiopia in 2005, triggering the formation of a new sea.

About rifting

• Rifting refers to the geological process in which a single tectonic plate is split into two or more plates separated by divergent plate boundaries.
• This process leads to the emergence of a lowland region known as a rift valley, which can occur either on land or at the bottom of the ocean. These rift valleys occur due to the movement of Earth’s tectonic plates.

What is happening in Africa?

• The three plates — the Nubian African Plate, Somalian African Plate and Arabian Plate — are separating at different speeds.
• The Arabian Plate is moving away from Africa at a rate of about an inch per year, while the two African plates are separating even slower.
• As the Somali and Nubian tectonic plates continue to pull apart from each other, a smaller continent will be created from the rift, which will include present-day Somalia and parts of Kenya, Ethiopia, and Tanzania.
• This new ocean will result in East Africa becoming a separate small continent with its own unique geographic and ecological characteristics.

Challenges and consequences of this rifting:

• Displacement of communities, settlements and various flora and fauna.
• Impact their habitats due to climate change, resulting in environmental degradation.
• Rapid urbanisation and increased settlements will put pressure on natural resources, leading to a scarcity of water, energy and food.
• Uncontrolled waste disposal.
• Some species will disappear, while others will become endangered due to habitat changes.