Geography: August 2022 Current Affairs - UPSC PDF Download

Aridity Anomaly Outlook Index: IMD

Why in News?
Recently, Indian Meteorological Department (IMD) has released the Aridity Anomaly Outlook (AAO) Index of July 2022, which says at least 85% of districts face arid conditions across India.

What is the Aridity Anomaly Outlook Index?

• About:
  • The index monitors agricultural drought, a situation when rainfall and soil moisture are inadequate to support healthy crop growth till maturity, causing crop stress.
  • An anomaly from the normal value signifies a water shortage in these districts that could directly impact agricultural activity.
  • It is Developed by the India Meteorological Department (IMD).
• Characteristics:
  • A real-time drought index in which water balance is considered.
  • The Aridity Index (AI) is computed for weekly or two-week periods.
  • For each period, the actual aridity for the period is compared to the normal aridity for that period.
  • Negative values indicate a surplus of moisture while positive values indicate moisture stress.
• Parameters:
  • Actual evapotranspiration and calculated potential evapotranspiration, which require temperature, wind and solar radiation values.
  • Actual evapotranspiration is the quantity of water that is actually removed from a surface due to the processes of evaporation and transpiration.
  • Potential evapotranspiration is the maximum attainable or achievable evapotranspiration for a given crop due to evaporation and transpiration.
• Applications:
  • Impacts of drought in agriculture, especially in the tropics where defined wet and dry seasons are part of the climate regime.
  • Both winter and summer cropping seasons can be assessed using this method.

What are the Findings?

• Only 63 of 756 districts are non-arid, while 660 are facing different degrees of aridity — mild, moderate and severe.
• Some 196 districts are in the grip of a ‘severe’ degree of dryness and 65 of these are in Uttar Pradesh (highest).
  • Bihar had the second highest number of districts (33) experiencing arid conditions. The state also has a high rainfall deficit of 45%.
• Other districts facing ‘severe arid’ conditions are Jharkhand, Haryana, Madhya Pradesh, Delhi, Telangana, Maharashtra, Andhra Pradesh, Jammu and Kashmir, Punjab, West Bengal, Rajasthan, Karnataka and Tamil Nadu.
• The SPI on the DEWS platform also highlights a persisting rainfall deficit in these areas in the last six months.
• Arid conditions have impacted the ongoing kharif sowing, as the area sown under different kharif crops as of July, 2022, was less by 13.26 million hectares compared to the corresponding period in 2021.

What is the Standardised Precipitation Index (SPI)?

• The SPI is a widely used index to characterize meteorological drought on a range of timescales.
• On short timescales, the SPI is closely related to soil moisture, while at longer timescales, the SPI can be related to groundwater and reservoir storage.
• The SPI on the Drought Early Warning System (DEWS), a real-time drought monitoring platform managed by the Indian Institute of Technology, Gandhinagar (IIT-G) platform highlights a persisting rainfall deficit in these areas in the last six months.
• UP, Jharkhand, Bihar, West Bengal and some parts of the North East are under extreme drought situation and agriculture of these regions might be affected.

What is the India Meteorological Department (IMD)?

• IMD was established in 1875.
• It is an agency of the Ministry of Earth Sciences.
• It is the principal agency responsible for meteorological observations, weather forecasting and seismology.

How did Continents Form

Context: According to a new study published in Nature, Earth’s continents were formed by massive meteorite impacts that were prevalent during the first billion years of our planet’s four and a half billion-year history.
The theory that giant meteorite impacts formed continents had been around for decades, but until now, there was little solid evidence for its support. Meteorite impacts generated massive energy to form oceanic plates, which later evolved into continents.

• Current theory: The most commonly accepted theory in place attributes continent formation to the movement of tectonic plates (as per the theory of Plate Tectonics)

Evidence for Meteorite impact theory:

• Zircon crytals in Pilbara Craton: The researchers looked for evidence in zircon crystals embedded in rocks from the Pilbara Craton in Western Australia. This craton is the remnant of an ancient crust that began forming more than three billion years ago.
• Cratons: A craton is an old and stable part of the continental lithosphere, which consists of Earth’s two topmost layers, the crust and the uppermost mantle

• “Studying the composition of oxygen isotopes in these zircon crystals revealed a ‘top-down’ process starting with the melting of rocks near the surface and progressing deeper, consistent with the geological effect of giant meteorite impacts.
• Zircons are formed by the crystallisation of magma or are found in metamorphic rocks. They act as tiny time capsules, recording the period of geologic activity. Newer zircon adds to the original crystal as time progresses.

Need for understanding:

• Understanding the formation and evolution of continents is important, as it is the key to reserves of metals such as lithium, tin and nickel.
• Most of Earth’s biomass and most humans live on these landmasses, so understanding how continents form and evolve is crucial.

Theory of Plate Tectonics

Alfred Wegener in his paper in 1912 hypothesized that all of the modern-day continents had previously been clumped together in a supercontinent he called Pangaea. Over 200 million years, the continents had drifted apart. This was called continental drift theory. But it was widely ridiculed as a mere hypothesis. It was only in the 1960s, when technologies had developed that the validity of his theory was proved and further enhanced by McKenzie and Parker, through their theory of plate tectonics.

To read more information on continental drift theory :

• PPT: Continental Drift Theory

NASA highlights loss of mangrove cover on Katchal island in the Nicobars

Context
The United States National Aeronautics and Space Administration (NASA) recently highlighted the loss of mangrove cover on Katchal Island, a part of India’s Nicobar archipelago.

About

• The NASA Earth Observatory showed a map of the island August 8, 2022, shot from a satellite. It depicted tidal wetland loss from 1999 through 2019 in orange colour.

• The map above shows the real extent of tidal wetlands lost between 1992 and 2019 on Katchal Island in the Nicobar Islands in the eastern Indian Ocean.
• After the magnitude-9.2 Aceh-Andaman earthquake in December 2004, the islands experienced up to 3 meters (10 feet) of land subsidence.
• This submerged many mangrove ecosystems, resulting in a loss of more than 90 percent of mangrove extent in some areas.

Key Findings

Tidal wetlands

• High-resolution mapping of losses and gains of Earth’s tidal wetlands found that 4,000 square kilometres of tidal wetlands were lost between 1999 and 2019.
• Mangroves had the highest ratio of loss to gain among the three types of tidal wetlands it studied. The other two were tidal flats and marshes.
• Some 27 per cent of the losses and gains were directly caused by human activity.
• Humans can alter wetlands through development, water diversion projects, or by converting the land to agriculture or aquaculture. 
• Other causes of wetland change were sea level rise, shoreline erosion, storms, altered sediment flow and subsidence.
• These can be either indirectly caused by humans or the result of natural coastal processes.

Katchal Island

• The Island of Katchal, was earlier referred to as ‘Tihnyu’ in the local language.
• Katchal is home to both indigenous and non-indigenous people and comprises of the Nicobarese Tribes, which are the original inhabitants along with migrated Tamilians, who joined towards the end of the British rule.
• A special permission is required to visit to the Island and is not open to tourists or outsiders without the permission and supervision of the local administration.
• The Katchal Island is the largest Island among all the other Nicobar Islands and was comprised of 35 villages prior to the Tsunami.
• The highest peak within the Island of Katchal is around 835 feet high.
• There are about 5 different languages spoken within this Island, including Tamil, Telugu, Nicobari, Hindi and Santhali.
• The Government of India has declared the Nicobar Islands to be an Aboriginal Tribal Reserve Area, to protect the tribes and natives from any kind of outside exploitation or over modernization of the zone, restricting even tourists without permission.
• The small and large hills of the Katchal Island are made of Calcareous Sandstone and marble slates and in the beautiful tropical forest of Katchal one will find lots of Pythons, Black Monkeys and Pigs.
• The main source of earning and the base of their economy used to lie only in the trade of Coconut, Betelnut or Arecanut product and bi-products, especially for the natives and village dwellers.

NOAA predicts above-average Atlantic hurricane season

Context
The on-going North Atlantic Ocean hurricane season will be more active than normal from August to November, according to the latest update issued by the United States’ National Oceanic and Atmospheric Administration (NOAA), an American research Institute.

About

Key-highlights of the predictions

• NOAA predicted a 60 per cent chance of an above-normal Atlantic hurricane season.
• The researchers said that there would be 14-20 named storms in the remainder of the season, out of which 6-10 would likely become hurricanes and 3-5 could turn into major hurricanes.
• La Niña aids in the formation, intensification and propagation of hurricanes in the North Atlantic Ocean.
• Generally the season of hurricanes began in June but till July this year there had no hurricanes and only three named storms have formed in the North Atlantic basin.

 What are Hurricanes?

• Hurricanes are large, swirling storms.
• They can produce winds of 119 kilometres per hour (74 mph) or higher.
• An Atlantic hurricaneor tropical storm is a tropical cyclone that forms in the Atlantic Ocean, primarily between the months of June and November.

Why hurricanes are dangerous?

• Winds from a hurricane can damage buildings and trees. Hurricanes form over warm ocean waters. Sometimes they strike land.
• When a hurricane reaches land, it pushes a wall of ocean water ashore. This wall of water is called a storm surge.
• Heavy rain and storm surge from a hurricane can cause flooding in the nearby island regions.

Parts of a Hurricane

• Eye: The eye is the "hole" at the centre of the storm. Winds are light in this area. Skies are partly cloudy, and sometimes even clear.
• Eye wall: The eye wall is a ring of thunderstorms. These storms swirl around the eye. The wall is where winds are strongest and rain is heaviest.
• Rain bands: Bands of clouds and rain go far out from a hurricane's eye wall. These bands stretch for hundreds of miles. They contain thunderstorms and sometimes tornadoes.

How Does a Storm Become a Hurricane?

• A hurricane starts out as a tropical disturbance. This is an area over warm ocean waters where rain clouds are building.
• A tropical disturbance sometimes grows into a tropical depression. This is an area of rotating thunderstorms with winds of 62 km/hr (38 mph) or less.
• A tropical depression becomes a tropical storm if its winds reach 63 km/hr (39 mph).
• A tropical storm becomes a hurricane if its winds reach 119 km/hr (74 mph).

What are the Conditions in favour of hurricanes in North Atlantic Ocean?

• There are several atmospheric and oceanic conditions that are still in favour of an active hurricane season.
• La Nina: This includes La Niña conditions, which are favoured to remain in place for the rest of 2022 and could allow the on-going high-activity era conditions to dominate, or slightly enhance hurricane activity.
• Weaker Tropical Trade Winds: In addition to a continued La Niña, weaker tropical Atlantic trade winds, an active west African Monsoon and likely above-normal Atlantic sea-surface temperatures set the stage for an active hurricane season and are reflective of the on-going high-activity era for Atlantic hurricanes.

How Are Hurricanes Named?

• There can be more than one hurricane at a time. This is one reason hurricanes are named. Names make it easier to keep track of and talk about storms.
• Each year, tropical storms are named in alphabetical order. The names come from a list of names for that year.
• There are six lists of names. Lists are reused every six years. If a storm does a lot of damage, its name is sometimes taken off the list. It is then replaced by a new name that starts with the same letter.

Last major Hurricanes in the North Atlantic Ocean:
2005 Dennis Katrina Rita Stan Wilma
Hurricane Santa Ana , 1825

‘Nadis’ of Rajasthan

Context: Rajasthan’s nadis, an insurance against a dry summer.

Concept: Nadis or Talabs (ponds)

• These are shallow depressions strewn across the rural landscape in the arid regions of Jodhpur and Barmer districts.
• The water collected in these tanks will quench the thirst of cattle and human beings as well as wild animals during the dry months later in the year.
• The rural communities utilise these structures for storage of rain water with the application of traditional knowledge and locally available materials in view of the highly variable and scanty rainfall in the State.
• These will create micro-climates which will help improve local resilience against the vagaries of global warming and climate change.
• (i)The Ramrawas Kalan village, situated 49 km north-east of Jodhpur has two nadis. (ii)The two bigger structures called Deoli and Chan are in Orans (associated with local deities) or sacred forest groves 10 km away from the village.

Traditional Water Conservation Systems in India:

Rare Earth Minerals  

Context 

• The United States and key partner countries have announced the establishment of the Minerals Security Partnership (MSP), a new initiative to bolster critical mineral supply chains.
• It is an alternative to China to ensure key industrial supplies.
• India is not part of this arrangement.

Minerals Security Partnership (MSP):

• The US and 10 countries including Australia, France, Canada, Finland, Germany, Japan, South Korea, Sweden, the United Kingdom, and the European Commission have come together to form the MSP. 
• The goal of the MSP is to ensure that critical minerals are produced, processed, and recycled in a manner that supports the ability of countries to realise the full economic development benefit of their geological endowments. 
• The MSP will help catalyse investment from governments and the private sector for strategic opportunities across the full value chain that adhere to the highest environmental, social, and governance standards.
• The alliance is seen as an alternative to China, which has created processing infrastructure in rare earth minerals and has acquired mines in Africa for elements such as Cobalt. 

Rare Earth Minerals: 

• The 17 rare earth elements (REE). REEs are classified as light RE elements (LREE) and heavy RE elements (HREE). 
• India has the fifth-largest reserves of rare earth minerals in the world.
• Due to the radioactivity of monazite sands, Indian Rare Earths Ltd under the Department of Atomic Energy is the sole producer of rare earth compounds.
• Globally, China has a monopoly over rare earth, after the USA's retreat in this industry due to high environmental and health concerns. 

Why are these minerals important?

• Minerals like Cobalt, Nickel, and Lithium are required for batteries used in electric vehicles.
• REEs are an essential component of more than 200 consumer products, including mobile phones, computer hard drives, electric and hybrid vehicles, semiconductors, flatscreen TVs and monitors, and high-end electronics.
• Several potential improvements to the Li-ion battery technology has put the industry in advanced stages of commercialisation. 

Strategic Importance to India:

• Rare earth minerals are very crucial for India in order to reduce the energy burden. It is an important component in the manufacture of hybrid vehicles, fuel cells and LEDs. According to India's ambitious plan, 80 % of the country’s two- and threewheeler fleet, 40% of buses, and 30 to 70 % of cars will be EVs by 2030.
• It is indispensable in the manufacture of advanced defence equipment.
• Essential for purifying the rivers flowing across the country.
• It is used in the manufacture of electronic gadgets which would help in our Digital India programme. 

India’s major concern:

• India is seen as a late mover in attempts to enter the lithium value chain, coming at a time when EVs are predicted to be a sector ripe for disruption.
• India will have to depend on other countries, especially China to power its energy transition plans to electric vehicles, if it fails to explore and produce these minerals.

To read more about minerals:

• NCERT-Summary Mineral Energy Resources-1 
• NCERT-Summary Mineral Energy Resources-2