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Subject: Geography

  • La Soufriere volcanic eruption

    Sulphur dioxide (SO2) emissions from La Soufriere volcano eruption in the Caribbean have reached all the way to India.

    Why in news?

    • Its eruption has sparked fear of increased pollution levels in the northern parts of India and acid rain.
    • Volcanic plumes can cause aviation and air quality hazards.

    La Soufriere

    • It is an active stratovolcano on the Caribbean island of Saint Vincent in Saint Vincent and the Grenadines.
    • It is the highest peak in Saint Vincent and has had five recorded explosive eruptions since 1718.

    Impact of such eruptions

    • Volcanic emissions reaching the stratosphere can have a cooling effect on global temperatures.
    • The most significant climate impacts from volcanic injections into the stratosphere come from the conversion of sulphur dioxide to sulphuric acid, which condenses rapidly in the stratosphere to form fine sulphate aerosols.
    • The aerosols increase the reflection of radiation from the Sun back into space, cooling the Earth’s lower atmosphere or troposphere.

    Try this PYQ:

    Q.Which of the following adds/add carbon dioxide to the carbon cycle on the planet Earth?

    1. Volcanic action
    2. Respiration
    3. Photosynthesis
    4. Decay of organic matter

    Select the correct answer using the code given below:

    (a) 1 and 3 only

    (b) 2 only

    (c) 1, 2 and 4 only

    (d) 1, 2, 3 and 4

  • How Asian desert dust enhances Indian summer monsoon?

    A new study has revealed how dust coming from the deserts in West, Central and East Asia plays an important role in the Indian Summer Monsoon.

    Try this PYQ:

    With reference to ‘Indian Ocean Dipole (IOD)’, sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct?

    1. IOD phenomenon is characterized by a difference in sea surface temperature between tropical Western Indian Ocean and tropical Eastern Pacific Ocean.
    2. An IOD phenomenon can influence an El Nino’s impact on the monsoon.

    Select the correct Option using the code given below:

    (a) Only 1

    (b) Only 2

    (c) Both 1 and 2

    (d) Neither 1 nor 2

    Why study dust?

    • Many studies have shown that the dust emission scheme is extremely sensitive to climate change.
    • Understanding these mechanisms and effects of dust will help us understand our monsoon systems in the face of global climate change.

    Impact of dust on Indian Monsoon

    • Dust swarms from the desert when lifted by strong winds can absorb solar radiation and become hot.
    • This can cause heating of the atmosphere, change the air pressure, wind circulation patterns, influence moisture transport and increase precipitation and rainfall.
    • A strong monsoon can also transport air to West Asia and again pick up a lot of dust.
    • The researchers say this is a positive feedback loop.

    Role of the Iranian plateau

    • Not just the dust from the Middle East, the Iranian Plateau also influences the Indian Summer Monsoon.
    • The hot air over the Iranian Plateau can heat the atmosphere over the plateau, strengthen the circulation over the deserts of the Arabian Peninsula and increase dust emission from the Middle East.
    • The researchers also explain how the Indian Summer Monsoon has a reverse effect and can increase the winds in West Asia to produce yet more dust.

    Transported aerosols

    • Deserts across the globe play important roles in monsoons.
    • The dust aerosols from deserts in West China such as the Taklamakan desert and the Gobi Desert can be transported eastward to eastern China and can influence the East Asia summer monsoon.
    • And in the southwest United States, we have some small deserts that influence the North African monsoon.

    Anthropogenic contributions

    • Some studies have found that the anthropogenic aerosols emitted from the Indian subcontinent can decrease summer monsoon precipitation.
    • However, some others found that absorbing aerosols such as dust can strengthen the monsoon circulation.

    Minor components

    • Earlier it was believed that dust from deserts across the globe will have the same components.
    • But it was found that different deserts have different chemical compositions and this can influence the dust’s properties.
    • For example, dust from the Middle East has the more absorbing ability of solar radiation than dust from North Africa and this difference in absorbing ability might influence monsoon systems.

  • Indian monsoon 25 million years ago resembled present day Australia’s

    Using leaf fossils, researchers have found that the Indian monsoon 25 million years ago resembled present-day Australia’s.

    Try this PYQ:

    Q.Which one of the following is the appropriate reason for considering the Gondwana rocks as the most important rock systems of India?

    (a) More than 90% of limestone reserves of India are found in them

    (b) More than 90% of India’s coal reserves are found in them

    (c) More than 90% of fertile black cotton soils are spread over them

    (d) None of the reasons given above is appropriate in this context

    India’s drift

    • About 180 million years ago, India separated from the ancient supercontinent Gondwana and took a long northward journey of about 9,000 km to join Eurasia.
    • During this journey, the subcontinent moved from the southern hemisphere, crossed the Equator to reach its current position in the northern hemisphere.
    • Due to these changing latitudes, it experienced different climatic conditions, and a new study has now tried to map these climatic variations using leaf fossils.

    Clueless over the evolution of monsoon

    • The evolution of the monsoonal climate in India is still debatable and not fully understood.
    • Though recent data indicates that the monsoon system we experience now dates back to about 25 million years, it is still unclear how the climate was during its long voyage.

    Indian research

    • The researchers analysed the morphological characters of fossil leaves collected from Deccan Volcanic Province, East Garo Hills of Meghalaya, Gurha mine in Rajasthan and Makum Coalfield in Assam.
    • The four fossil assemblages were found to be from four different geological ages.
    • It has been observed from across the globe that plant leaf morphological characters such as apex, base and shape are ecologically tuned with the prevailing climatic conditions.
    • The research applied this model to characterize the past monsoon from fossil leaves.

    It’s finding

    • The results indicated that the fossil leaves from India were adapted to an Australian type of monsoon and not the current Indian monsoon system during its voyage.
    • The reconstructed temperature data show that the climate was warm (tropical to subtropical) at all the studied fossil sites with temperatures varying from 16.3–21.3 degrees C.
    • All the fossil sites experienced high rainfall, which varied from 191.6 cm to 232 cm.

  • [pib] Coalition for Disaster resilient Infrastructure (CDRI)

    The Prime Minister has recently addressed the third edition of the annual conference of the Coalition for Disaster resilient Infrastructure (CDRI).

    What is CDRI?

    • The CDRI is an international coalition of countries, UN agencies, multilateral development banks, the private sector, and academic institutions that aim to promote disaster-resilient infrastructure.
    • Its objective is to promote research and knowledge sharing in the fields of infrastructure risk management, standards, financing, and recovery mechanisms.
    • It was launched by the Indian PM Narendra Modi at the 2019 UN Climate Action Summit in September 2019.
    • CDRI’s initial focus is on developing disaster-resilience in ecological, social, and economic infrastructure.
    • It aims to achieve substantial changes in member countries’ policy frameworks and future infrastructure investments, along with a major decrease in the economic losses suffered due to disasters.

    Try this PYQ:

    Q.Consider the following statements:

    1. Climate and Clean Air Coalition (CCAC) to Reduce Short Lived Climate Pollutants is a unique initiative of G20 group of countries
    2. The CCAC focuses on methane, black carbon and hydrofluorocarbons.

    Which of the above statements is/are correct?

    (a) 1 only

    (b) 2 only

    (c) Both 1 and 2

    (d) Neither 1 nor 2

    Its inception

    • PM Modi’s experience in dealing with the aftermath of the 2001 Gujarat earthquake” as the chief minister led him to the idea.
    • The CDRI was later conceptualized in the first and second edition of the International Workshop on Disaster Resilient Infrastructure (IWDRI) in 2018-19.
    • It was organized by the National Disaster Management Authority (NDMA), in partnership with the UN Office for Disaster Risk Reduction (UNDRR), the UN Development Programme, the World Bank, and the Global Commission on Adaptation.

    Its diplomatic significance

    • The CDRI is the second major coalition launched by India outside of the UN, the first being the International Solar Alliance.
    • Both of them are seen as India’s attempts to obtain a global leadership role in climate change matters and were termed as part of India’s stronger branding.
    • India can use the CDRI to provide a safer alternative to China’s Belt and Road Initiative (BRI) as well.

  • What is Rule Curve of a river?

    The Supreme Court has warned the Tamil Nadu Chief Secretary against the failure to give information on the rule curve for Mullaperiyar dam.

    Do you know?

    The Mullaperiyar dam is located in Kerala on the river Periyar but is operated and maintained by the neighbouring state of Tamil Nadu.

    What is the Rule Curve?

    • A rule curve or rule level specifies the storage or empty space to be maintained in a reservoir during different times of the year.
    • Here the implicit assumption is that a reservoir can best satisfy its purposes if the storage levels specified by the rule curve are maintained in the reservoir at different times.
    • It decides the fluctuating storage levels in a reservoir.
    • The gate opening schedule of a dam is based on the rule curve.
    • It is part of the “core safety” mechanism in a dam.

    Why such a move?

    • During the high-voltage hearing, the Tamil Nadu government blamed Kerala for delaying the finalization of the rule curve for the 123-year-old dam.
    • Kerala government has accused Tamil Nadu of adopting an “obsolete” gate operation schedule dating back to 1939.

    About Mullaperiyar Dam

    • Mullaperiyar Dam is a masonry gravity dam on the Periyar River in the Indian state of Kerala.
    • It is located on the Cardamom Hills of the Western Ghats in Thekkady, Idukki District of Kerala.
    • It was constructed between 1887 and 1895 by John Pennycuick and also reached an agreement to divert water eastwards to the Madras Presidency area (present-day Tamil Nadu).
    • It has a height of 53.6 m from the foundation, and a length of 365.7 m.
    • The Periyar National Park in Thekkady is located around the dam’s reservoir.
    • The dam is built at the confluence of Mullayar and Periyar rivers.

  • Places in news: Mount Sinabung

    Indonesia’s Mount Sinabung volcano sent a cloud of hot ash as high as 3 km today, in its first big eruption since August last year.

    Mount Sinabung

    • It is a Pleistocene-to-Holocene stratovolcano in the Karo plateau of Karo Regency, North Sumatra, Indonesia.
    • It is created by the subduction of the Indo-Australian Plate under the Eurasian Plate.
    • It erupted in 2010 after a 400-year-long hiatus and has been continuously active since September 2013.

    Why frequent eruptions?

    • Indonesia straddles the “Pacific ring of fire” with nearly130 active volcanoes, more than any other country.
    • Sinabung had been inactive for centuries before it erupted again in 2010.

    Try this PYQ:

    Q.Consider the following statements:

    1. The Barren Island volcano is an active volcano located in the Indian Territory.
    2. Barren Island lies about 140 km east of Great Nicobar
    3. The last time the Barren Island volcano erupted was in 1991 and it has remained inactive since then.

    Which of the statements given above is/are correct? (CSP 2018)

    (a) 1 only

    (b) 2 and 3 only

    (c) 3 only

    (d) 1 and 3

    What is the Pacific ring of fire?

    • The Pacific Ring of Fire is a region around much of the rim of the Pacific Ocean where many volcanic eruptions and earthquakes occur.
    • It includes the Pacific coasts of South America, North America and Kamchatka, and some islands in the western Pacific Ocean.
    • It is a direct result of plate tectonics: specifically the movement, collision and destruction of lithospheric plates under and around the Pacific Ocean.
    • The collisions have created a nearly continuous series of subduction zones, where volcanoes are created and earthquakes occur.

  • What is Laschamp Excursion?

    This newscard is an excerpt from the original article published in DownToEarth.

    The world experienced a few centuries of apocalyptic conditions 42,000 years ago, triggered by a reversal of the Earth’s magnetic poles combined with changes in the Sun’s behaviour. This event is called as Laschamps Excursion.

    Try this PYQ from CSP 2018:

    Q.The term “sixth mass extinction/sixth extinction” is often mentioned in the news in the context of the discussion of

    (a) Widespread monoculture Practices agriculture and large-scale commercial farming with indiscriminate use of chemicals in many parts of the world that may result in the loss of good native ecosystems.

    (b) Fears of a possible collision of a meteorite with the Earth in the near future in the manner it happened 65million years ago that caused the mass extinction of many species including those of dinosaurs.

    (c) Large scale cultivation of genetically modified crops in many parts of the world and promoting their cultivationin other Parts of the world which may cause the disappearance of good native crop plants and the loss offood biodiversity.

    (d) Mankind’s over-exploitation/misuse of natural resources, fragmentation/loss, natural habitats, destructionof ecosystems, pollution and global climate change.

    Laschamp Excursion

    • The Laschamp event was a geomagnetic excursion (a short reversal of the Earth’s magnetic field). It occurred 41,400 years ago, during the end of the Last Glacial Period.
    • This event is named after the village where it was discovered in the French Massif Central.
    • It led to series of catastrophic events like the ozone layer was destroyed, electrical storms raged across the tropics, solar winds generated spectacular light shows (auroras), Arctic air poured across North America, ice sheets and glaciers surged and weather patterns shifted violently.
    • During these events, life on earth was exposed to intense ultraviolet light, Neanderthals and giant animals known as megafauna went extinct, while modern humans sought protection in caves.

    The Adams Event

    • This last major geomagnetic reversal triggered a series of dramatic events that have far-reaching consequences for our planet.
    • Because of the coincidence of seemingly random cosmic events and the extreme environmental changes found around the world 42,000 years ago, researchers have called this period the “Adams Event”.

  • India and Australia were evolutionary neighbours

    Bhimbetka, which has yielded a fossil of Dickinsonia dating back about 550 million years, is the first time the particular fossilized organism has been recorded in India.

    Why does this fossil matter?

    • It dates back to an era regarded as the precursor to the explosion of life on earth during the Cambrian period.
    • Thus it puts India firmly on the map for studies of the Ediacaran era along with Australia and Russia.

    Here’s what makes the discovery a global milestone:

    (a) Ediacaran Period

    • The finding gives lead about the earliest living species during a period of the earth’s history known as the Ediacaran, named after the Ediacara Hills in South Australia.
    • This is the period in Earth’s history when Dickinsonia and several multicellular organisms existed.
    • It was approximately 635 million years ago (Ma) and 541 Ma, with the living creatures of the era, called vendobionts.

    Now take this opportunity to revise the Geological time scale from your NCERTs. Try differentiating between different era, periods and epoch.

    (b) India’s Proximity to Australia

    • Studies of the rock characteristics in and around Bhimbetka show that they share several characteristics with rocks in Australia.
    • Dickinsonia fossils from India were found by the scientists to be identical to the Rawnsley Quartzite in South Australia.
    • This provides evidence of their age and the proximity of the two landmasses in Gondwanaland in that era.
    • The evidence however did not support reconstructions adjusted for the polar wander phenomenon [which involves motion of continents over geologic time and its impacts].

     Use of Zircon dating

    • The age of fossil rock is determined using Zircon isotopes.
    • Zircon dating of the youngest Maihar sandstone in Madhya Pradesh puts its age at 548 Ma.
    • The lower Bhander group in the Son and Chambal valleys yielded an isotope-derived age for limestones ranging from 978 Ma to 1073 Ma, situating it in the older Tonian period.
    • The Ediacaran period was the precursor to the Cambrian (about 541 Ma to 485.4 Ma) when the earth witnessed an explosion of life forms and much of which makes up modern animal life today.

  • Cost of development in the fragile mountains

    The article explains the relationship between development activities in Uttarakhand and the devastating floods.

    Cause of recent flash flood in Uttarakhand

    • According to Planet Labs, ice along with frozen mud and rocks fell down from a high mountain inside the Nanda Devi Sanctuary, from a height of 5,600 m to 3,300 m.
    • This created an artificial lake within the sanctuary in Rontigad, a tributary of Rishi Ganga.
    • Within eight hours, this lake burst open and its water, laden with mud and stones, rushed through the Rishi Ganga gorge which opens near Reni.
    • Studies say that the current winter season has seen little rain and snow, with temperatures being highest in the last six decades.
    •  So, the effects of chemical weathering were much more active in the higher Himalayas.
    •  There is a possibility of more such events this year.

    Factors responsible

    1) Development with no regard for the environment

    • As a mountain system, the Himalayas have had earthquakes, avalanches, landslides, soil erosion, forest fires and floods, and these are its natural expressions, parts of its being.
    • Except for earthquakes, humans have directly contributed towards aggravating all the other phenomena.
    • The Ravi Chopra committee formed by the SC recommended closure of all the 24 hydro projects in question by Wildlife Institute of India.
    • The SC also formed another committee to look at the impact of the Chaardham road project.
    • Road and hydro projects are being operated in the Himalayas with practically no rigorous research on the ecological history of the area, cost-benefit analysis and many other aspects including displacement of communities, destruction of biodiversity, agricultural land, pastures as well as the cultural heritage of the area.

    Dilution of Environmental Impact Assessment rules

    • Earlier, while independent experts carried out the Environmental Impact Assessment (EIA), today it is assigned to a government agency, which does the work for other government departments.
    • Furthermore, during the lockdown, the government changed the EIA rules and diluted labour laws (most of the workers in both the affected projects belong to unorganised sector) in the name of pandemic measures.

    2) Climate change

    • Another factor which cannot be overlooked is that of climate change.
    • Studies have suggested that the pace of this change is faster in mountains and fastest in the Himalayas.
    • While earthquakes and weathering work at their own pace, climate change can contribute towards altering their natural speed.

    Need for studying the 2013 calamity

    •  We can look back at the terrible calamity of 2013, and see how it washed away the encroachments in river areas-dams, barrages, tunnels, buildings, roads.
    • The communities paid a much heavier price than what they received in compensation.
    • Further, the 2013 calamity has to be studied and understood in all the other regions and river valleys of Uttarakhand, Western Nepal and Himachal.
    • It was not specific to Kedarnath, although much of the focus was directed there.
    • Till date, we don’t have any white paper on this calamity.
    • The India Meteorological Department failed in its prediction and wrongly announced at the end of the first week of June that the monsoon will reach Uttarakhand by June 27-28.
    • It reached on June 16-17 with 300-400 per cent more rain, a record never heard of before.
    •  24 big and small hydro projects were destroyed.
    • The muck created by these projects was also the cause of their destruction.
    • The road debris, always dumped in rivers, was another cause.
    • The smaller rivers were more aggressive in 2013.

    Consider the question “What are the factors responsible for the devastating floods in the Uttarakhand? Suggest the measures for disaster mitigation.”

    Conclusion

    The Himalayas have been giving us life through water, fertile soil, biodiversity, wilderness and a feel of spirituality. We cannot and should not try to control or dictate the Himalayas.

  • A resilient future for Uttarakhand

    The article discusses the factors that could explain the cause of the recent flash floods in Uttarakhand and suggest the immediate steps to deal with such disasters.

    What makes Uttarakhand vulnerable

    • Days after a glacier burst in the Chamoli district of Uttarakhand caused flash floods, the scientific community is still struggling to understand what triggered the disaster.
    • Uttarakhand is located in the midst of young and unstable mountains and is subject to intense rainfall.
    • For years experts have voiced their fears about an impending disaster due to climate change, rapid and indiscriminate construction activities, and the subsequent ecological destruction in the region.
    • Studies have shown that widespread settlements, farming, cattle grazing and other anthropogenic activities could destroy the natural barriers that control avalanches and floods, thereby enhancing the possibilities of a glacial lake outburst flood.
    • The Hindu Kush Himalaya Assessment Report (2019) had pointed out that one-third of the Hindu Kush Himalaya’s glaciers would melt by 2100 and potentially destabilise the river regime in Asia, even if all the countries in the region fulfilled their commitments under the Paris Agreement.

    Possible causes of the current glacial outburst

    • The current glacier burst was loosely attributed to erosion, a build-up of water pressure, an avalanche of snow or rocks, landslides or an earthquake under the ice.
    • A rock mass, weakened from years of freezing and thawing of snow, may have led to the creation of a weak zone and fractures leading to a collapse that resulted in flash floods.

    Issue of construction activity

    • Experts and activists have incessantly asked for scrutiny into the construction of hydroelectric power projects in Uttarakhand.
    • There have also been allegations about the use of explosives in the construction of dams and other infrastructure.
    • In 2014, an expert committee led by Dr Ravi Chopra, instituted to assess the role of dams in exacerbating floods, provided hard evidence on how haphazard construction of dams was causing irreversible damage to the region.

    7 Immediate steps

    • 1) Investing in resilience planning, especially in flood prevention and rapid response.
    • 2) Climate proofing the infrastructure such as by applying road stabilisation technologies for fragile road networks and strengthening existing structures like bridges, culverts and tunnels.
    • 3) Strengthening embankments with adequate scientific know-how
    • 4) Reassessing development of hydropower and other public infrastructure.
    • 5) Investing in robust monitoring and early warning system.
    • 6) Establishing implementable policies and regulatory guidelines to restrict detrimental human activities, including responsible eco- and religious tourism policies.
    • 7) Investing in training and capacity building to educate and empower local communities to prevent and manage risks effectively.

    Consider the question “What are the factors that make Uttarakhand vulnerable to natural disasters? Suggest the measures to prevent and deal with the disasters” 

    Conclusion

    India needs to urgently rise up to the challenge by applying innovative and inclusive solutions that support nature and marginalised communities, to restore and rebuild a resilient future for Uttarakhand.