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Subject: Environment

  • Africa’s Great Green Wall (GGW) Program

    Africa’s Great Green Wall (GGW) program to combat desertification in the Sahel region is an important contribution towards combating climate change, Food and Agriculture Organization (FAO) said in a study.

    Note the countries swept by the GGW project on the African map.

    About GGW Program

    • The Great Green Wall project is conceived by 11 countries located along the southern border of the Sahara and their international partners, is aimed at limiting the desertification of the Sahel zone.
    • Led by the African Union, the initiative aims to transform the lives of millions of people by creating a mosaic of green and productive landscapes across North Africa.
    • The initial idea of the GGW was to develop a line of trees from east to the west bordering the Saharan Desert.
    • Its vision has evolved into that of a mosaic of interventions addressing the challenges facing the people in the Sahel and the Sahara.

    Why was such project incepted?

    • The project is a response to the combined effect of natural resources degradation and drought in rural areas.
    • It aimed to restore 100 million hectares of degraded land by 2030; only four million hectares had been restored between 2007 and 2019.
    • It is a partnership that supports communities working towards sustainable management and use of forests, rangelands and other natural resources.
    • It seeks to help communities mitigate and adapt to climate change, as well as improve food security.

     

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  • India, while moving to renewable energy needs to focus on sustainable well-being

    Context

    With current per capita emissions that are less than half the global average, India’s pledge to reach ‘net zero’ emissions by 2070 has cemented India’s credentials as a global leader.

    Implication of net-zero by 2070

    • The political implication of the date 2070 is that the world should get to ‘net-zero’ by 2050.
    • For that, the rich countries will need to do more and step up closer to their share of the carbon budget.
    • India’s stand also signals that it will not act under external pressure, as requiring equal treatment is the hallmark of a global power, and will have an impact on other issues.

    How focus on coal harms developing countries

    • The subject of oil was not touched at COP26, even as automobile emissions are the fastest growing emissions, because it is a defining feature of western civilisation.
    • Most abundant source of energy: Coal is the most abundant energy source, essential for base load in electrification, and the production of steel and cement.
    • Its use declines after the saturation level of infrastructure is reached.
    • Declining role of G-7 in rule setting: That India and China working together forced the G7 to make a retraction has signalled the coming of a world order in which the G7 no longer sets the rules.
    • Specific language on finance and adaptation: After 40 years there is more specific language on both finance and adaptation finally recognising that costs and near-term effects of climate change will hit the poorest countries hardest.

    Feasibility of the goal of ‘net-zero’ by 2070

    • Seeing the challenge in terms of the scale and the speed of the transformation of the energy system assumes that India will follow the pathway of western civilisation.
    • Transition to electrification: India is urbanising as it is industrialising, moving directly to electrification, renewable energy and electric vehicles, and a digital economy instead of a focus on the internal combustion engine.
    • Most of the infrastructure required has still to be built and automobiles are yet to be bought.
    • Investment vs. incurring cost: India will not be replacing current systems and will be making investments, not incurring costs.

    Challenge for the West

    • The consumption of affluent households both determines and accelerates an increase of emissions of carbon dioxide.
    • This is followed by socio-economic factors such as mobility and dwelling size.
    • In the West, these drivers have overridden the beneficial effects of changes in technology reflected in the material footprint and related greenhouse-gas emissions.
    • The West has yet to come out with a clear strategy of how it will remain within the broad contours of its carbon budget.
    • And increasing inequality and a rise of protectionism and trade barriers imposing new standards need to be anticipated.
    • This knowledge is essential for national policy as well as the next round of climate negotiations.

    Way forward for India

    • Climate change has to be addressed by the West by reducing consumption, not just greening it.
    • Shifting the consumption pattern: Consumption patterns need to be ‘shifted away from resource and carbon-intensive goods and services, e.g. mobility from cars and aircraft to buses and trains.
    • Reducing the carbon intensity: Along with’ reducing demand, resource and carbon intensity of consumption has to decrease, e.g. expanding renewable energy, electrifying cars and public transport and increasing energy and material efficiency’.
    • Equal distribution of wealth and affordable energy use: Equally important, will be achieving a’ more equal distribution of wealth with a minimum level of prosperity and affordable energy use for all’, e.g., housing and doing away with biomass for cooking.
    • Focused research group: The Government now needs to set up focused research groups for the conceptual frame of sustainable well-being.
    • It should analyse the drivers of affluent overconsumption and circulate synthesis of the literature identifying reforms of the economic systems as well as studies that show how much energy we really need for a decent level of well-being.

    Role for legislature

    • Fundamental duty: After the Stockholm Declaration on the Global Environment, the Constitution was amended in 1976 to include Protection and Improvement of Environment as a fundamental duty.
    • Use of provision under Article 253: Parliament used Article 253 to enact the Environment Protection Act to implement the decisions reached at the Stockholm Conference.
    • Enabling new set of legislation: The decisions at COP26 enable a new set of legislation around ecological limits, energy and land use, including the efficient distribution and use of electricity, urban design and a statistical system providing inputs for sustainable well-being.

    Consider the question “Examine the feasibility of India’s ‘net-zero’ target by 2070, also suggest the way forward for India to achieve the target by focusing on sustainable well being”

    Conclusion

    For India, in parallel with the infrastructure and clean technology thrust, the focus on a decent living standard leads to behavioural change in the end-use service, such as mobility, shelter and nutrition — for change modifying wasteful trends.

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  • Places in news: Majuli River Island

    Soil erosion, coupled with changing climatic conditions, has been writing a cruel destiny for the inhabitants of Majuli in Assam, the largest river island in the world.

    About Majuli Island

    • Majuli is a riverine island in the Brahmaputra River, Assam and in 2016 it became the first island to be made a district in India.
    • Majuli has shrunk as the river surrounding it has grown.
    • It had an area of 880 square kilometers (340 sq mi) at the beginning of the 20th century but having lost significantly to erosion it covers 553 square kilometers as at 2014.
    • It is the abode of the Assamese neo-Vaishnavite culture.

    Its formation

    • The island is formed by the Brahmaputra River in the south and the Kherkutia Xuti, an anabranch of the Brahmaputra, joined by the Subansiri River in the north.
    • It was formed due to course changes by the river Brahmaputra and its tributaries, mainly the Lohit.

     

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  • The heavy lifting on climate action must begin

    Context

    Glasgow’s success was that it finished building the scaffolding for climate action initiated through the Paris Agreement. But true success depends on whether countries are receptive to these nudges.

    What were the Glasgow climate meeting’s (COP26) successes and failures?

    • Strengthened Paris Agreement mechanism: Glasgow strengthened the Paris Agreement mechanism of eliciting pledges from countries and ratcheting them up over time.
    • It requested countries to update and strengthen 2030 emission targets in their NDCs by the end of 2022, earlier than previously expected.
    • Success at Glasgow was explicitly defined around ‘keeping 1.5 degrees alive’ through such pledges.
    • There are two problems with this interpretation.
    • First, the Paris, and Glasgow, approach focusing on target-setting gives insufficient importance to the challenge of implementing those targets.
    • A focus on shorter term targets and their implementation — which India to its credit has been highlighting — will be important.
    • Second, by calling on countries to strengthen targets to align with the Paris Agreement objectives without explicitly considering that countries have different roles and responsibilities in doing so risks side-stepping, again, the long-standing issue of climate equity.

    Phase-down clause for thermal power and implications for India

    • Phasing down coal power: A specific high profile clause calls for the ‘phase down of unabated coal power and phase out of inefficient fossil fuel subsidies’.
    • It was the Indian Minister who read out an amendment modifying ‘phase-out’ to ‘phase-down’ for coal.
    • India’s concerns: India’s real concerns included not precluding subsidies for social purposes, such as for cooking gas; querying whether from an equity point of view, all countries should be asked to limit coal use at the same time; and noting the lack of mention of oil and gas.
    • A positive for all from environmental point of view: From an environmental point of view, more explicit discussion of coal, but ideally all fossil fuels, is a positive, including for India.
    • Concerns on developmental view: From a developmental view, however, India is concerned that explicit mention of coal constrains us in our choice of fuel.
    • Way out for India: A possible way out is for India to explicitly seek global support for an accelerated transition away from coal, an approach taken by South Africa.

    Challenges and achievements at COP26

    [A] Measures for adaptations

    • Adaptation has long been neglected in global negotiations, reflecting a global power imbalance that places less weight on the concerns of vulnerable nations.
    • In this context, it was a partial win that Glasgow set up an explicit two year work programme for a ‘global goal’ on adaptation.
    • No development on agenda of loss and damage: The important complementary agenda of ‘loss and damage’ – compensating for unavoidable impacts that go beyond adaptation — received at most lip service.
    • Even though there was discussion of a specific mechanism, backed by funding, to the dismay of small, vulnerable nations, only a ‘dialogue’ was established.

    [B] Climate finance commitment issue not addressed

    • Commitment on climate finance not met: Climate finance promised to be the central issue of COP26, with considerable frustration from developing countries that the decade-long commitment of $100 billion had not been met.
    • Glasgow did no more than establish a work programme on post-2025 financing and continue tracking progress on the $100 billion.
    • The exception was a call to double adaptation finance by 2025.
    • Mobilising private finance: Former Bank of England Governor Mark Carney indicated that companies committed to net zero initiatives could marshal a scarcely believable $130 trillion, suggesting growing efforts to mobilise private finance.
    • Developing countries have long insisted that publicly funded climate finance is a right devolving from the ‘polluter pays’ principle rather than aid.

    [C] Paris rulebook

    • Completion of two elements of Paris Rulebook: There were two particularly important elements of what is called the ‘Paris Rulebook’ that were completed in Glasgow.
    • Transparency framework: First, the transparency framework was completed, which includes reporting rules and formats for emissions, progress on pledges and finance contributions.
    • Rules for carbon market: The second key was completion of agreed rules for carbon markets, the complexities of which had stymied agreement for four years.
    • Rules were put in place to limit the scope for ‘double-counting’ of credits by more than one country.

    Way forward for India

    • The real determinant of success or failure rests on national politics and popular support for climate change within countries — how countries use the scaffolding.
    • For India, these politics are complex because they revolve around simultaneously balancing concerns over whether our policy space will be limited by inequities embedded in the global mitigation efforts, and our own interests as a vulnerable country in enhancing and accelerating climate action.
    • A balanced view requires consideration of both objectives.

    Consider the question “Why climate finance continues to be a contentious issue in the negotiations over climate change? Suggest the way to balance the concerns over development with the efforts at climate action.”

    Conclusion

    The meeting hit many, but not all, of its procedural benchmarks by building scaffolding for the future. But the real determinant of success or failure rests on national politics and popular support for climate change within countries.

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  • Why Glasgow Climate Pact disappoints

    Context

    The Glasgow Climate Pact was adopted on Saturday and, as was to be expected, it is a mixed bag of modest achievements and disappointed expectations.

    Transition away from fossil fuel

    • The Pact is the first clear recognition of the need to transition away from fossil fuels, though the focus was on giving up coal-based power altogether.
    • India introduced an amendment at the last moment to replace this phrase with “phase down” and this played negatively with both the advanced as well as a large constituency of developing countries.
    • This amendment reportedly came as a result of consultations among India, China, the UK and the US.
    • As the largest producer and consumer of coal and coal-based thermal power, it is understandable that China would prefer a gradual reduction rather than total elimination.
    • India may have had similar concerns.

    Recognition of Adaptation

    • There is a welcome recognition of the importance of Adaptation and there is a commitment to double the current finance available for this to developing countries.
    • Since this amount is currently only $15 billion, doubling will mean $ 30 billion.
    • This remains grossly inadequate.
    • According to UNEP, adaptation costs for developing countries are currently estimated at $70 billion annually and will rise to an estimated $130-300 billion annually by 2030.
    • A start is being made in formulating an adaptation plan and this puts the issue firmly on the Climate agenda, balancing the overwhelming focus hitherto on mitigation.

    Disappointment on the issue of finance

    • The Paris Agreement target of $100 billion per annum between 2005-2020 was never met with the shortfall being more than half, according to some calculations.
    • There is now a renewed commitment to delivering on this pledge in the 2020-2025 period and there is a promise of an enhanced flow thereafter.
    • But in a post-pandemic global economic slowdown, it is unlikely these promises will be met.
    • In any event, it is unlikely that India will get even a small slice of the pie.
    • The same applies to the issue of compensation for loss and damage for developing countries who have suffered as a result of climate change for which they have not been responsible.

    Initiatives on methane and deforestation

    • Two important plurilateral outcomes could potentially develop into more substantial measures.
    • The most important is an agreement among 100 countries to cut methane emissions by 30 per cent by 2030.
    • India is not a part of this group.
    • Cutting methane emissions, which is generated mainly by livestock, is certainly useful but there is a much bigger methane emergency around the corner as the earth’s permafrost areas in Siberia, Greenland and the Arctic littoral begin to melt due to global warming that has already taken place and will continue to take place in the coming years.
    • Another group of 100 countries has agreed to begin to reverse deforestation by 2030.
    • India did not join the group due to concerns over a clause on possible trade measures related to forest products.

    Implications of US-China Joint Declaration on Climate Change for India

    • Declaration was a departure for China, which had held that bilateral cooperation on climate change could not be insulated from other aspects of their relations.
    • The declaration implies a shift in China’s hardline position.
    • It appears both countries are moving towards a less confrontational, more cooperative relationship overall.
    • This will have geopolitical implications, including for India, which may find its room for manoeuvre shrinking.

    Conclusion

    As in the past, the can has been kicked down the road, except that the climate road is fast approaching a dead-end. What provides a glimmer of light is the incredible and passionate advocacy of urgent action by young people across the world. This is putting enormous pressure on governments and leaders and if sustained, may become irresistible.

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  • Glasgow Climate Pact (COP26)

    The Glasgow Agreement was finally adopted after a last-minute intervention by India to water down language on “phasing out” coal to merely “phasing down”.

    Glasgow Agreement

    • The Glasgow meeting was the 26th session of the Conference of Parties to the UN Framework Convention on Climate Change, or COP26.
    • These meetings are held every year to construct a global response to climate change.
    • Each of these meetings produce a set of decisions which are given different names.
    • In the current case, this has been called the Glasgow Climate Pact.
    • Earlier, these meetings have also delivered two treaty-like international agreements, the Kyoto Protocol in 1997 and the Paris Agreement in 2015.

    What was achieved?

    [1] Mitigation:

    • The Glasgow agreement has emphasised that stronger action in the current decade was most critical to achieving the 1.5-degree target.
    • Accordingly, it has asked/decided:
    1. To strengthen their 2030 climate action plans, or NDCs (nationally-determined contributions), by next year
    2. Establish a work programme to urgently scale-up mitigation ambition and implementation
    3. To convene an annual meeting of ministers to raise ambition of 2030 climate actions
    4. Annual synthesis report on what countries were doing
    5. To convene a meeting of world leaders in 2023 to scale-up ambition of climate action
    6. Countries to make efforts to reduce usage of coal as a source of fuel, and abolish “inefficient” subsidies on fossil fuels
    7. Phase-down of coal, and phase-out of fossil fuels. This is the first time that coal has been explicitly mentioned in any COP decision.

    [2] Adaptation:

    • Most of the countries, especially the smaller and poorer ones, and the small island states, consider adaptation to be the most important component of climate action.
    • They have been demanding that at least half of all climate finance should be directed towards adaptation efforts.
    • As such, the Glasgow Climate Pact has:
    1. Asked the developed countries to at least double the money being provided for adaptation by 2025 from the 2019 levels.
    2. Created a two-year work programme to define a global goal on adaptation.

    [3] Finance:

    • Every climate action has financial implications. It is now estimated that trillions of dollars are required every year to fund all the actions necessary to achieve the climate targets.
    • Developed countries are under an obligation, due to their historical responsibility in emitting greenhouse gases.
    • They need to provide finance and technology to the developing nations to help them deal with climate change.
    • In 2009, developed countries had promised to mobilise at least $100 billion every year from 2020.
    • The 2020 deadline has long passed but the $100 billion promise has not been fulfilled.
    • The developed nations have now said that they will arrange this amount by 2023.

    [4] Accounting earlier failures

    The pact has:

    • Expressed “deep regrets” over the failure of the developed countries to deliver on their $100 billion promise.
    • It has asked them to arrange this money urgently and in every year till 2025
    • Initiated discussions on setting the new target for climate finance, beyond $100 billion for the post-2025 period
    • Asked the developed countries to provide transparent information about the money they plan to provide

    [5] Loss and Damage:

    The frequency of climate disasters has been rising rapidly, and many of these caused largescale devastation.

    • There is no institutional mechanism to compensate these nations for the losses, or provide them help in the form of relief and rehabilitation.
    • The loss and damage provision in the Paris Agreement seeks to address that.
    • Thanks to a push from many nations, substantive discussions on loss and damage could take place in Glasgow.
    • One of the earlier drafts included a provision for setting up of a facility to coordinate loss and damage activities.

    [6] Carbon Markets:

    • Carbon markets facilitate the trading of emission reductions.
    • They are considered a very important and effective instrument to reduce overall emissions.
    • A carbon market existed under Kyoto Protocol but is no longer there because the Protocol itself expired last year.
    • Developing countries like India, China or Brazil have large amounts of carbon credits left over because of the lack of demand as many countries abandoned their emission reduction targets.
    • The Glasgow Pact has offered some reprieve to the developing nations.
    • It has allowed these carbon credits to be used in meeting countries’ first NDC targets.

    Parallel Processes announced

    A lot of substantial action in Glasgow happened in parallel processes that were not a part of the official COP discussions.

    • India announced a Panchamrita (a mixture of five elements) of climate actions.
    • Brazil would advance its net-zero target year from 2060 to 2050.
    • China promised to come out with a detailed roadmap for its commitment to let emissions peak in 2030, and also for its 2060 net-zero target. Israel announced a net zero target for 2050.
    • Over 100 countries pledged to reduce methane emissions by at least 30 per cent from present levels by 2030.
    • Another set of over 100 countries promised to arrest and reverse deforestation by 2030.
    • Over 30 countries signed on to a declaration promising to work towards a transition to 100 percent zero-emission cars by the year 2040, at least in the leading car markets of the world.

     

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  • Kaiser-i-Hind is Arunachal’s State butterfly

    An elusive swallowtail butterfly carrying ‘India’ in its name and found in next-door China will become the State butterfly of Arunachal Pradesh.

    Kaiser-i-Hind

    Protection status: Schedule II of Wildlife (Protection) Act, 1972

    • Kaiser-i-Hind (Teinopalpus imperialis) literally means Emperor of India.
    • This butterfly with a 90-120 mm wingspan is found in six States along the Eastern Himalayas at elevations from 6,000-10,000 feet in well-wooded terrain.
    • The butterfly also flutters in Nepal, Bhutan, Myanmar, Laos, Vietnam and southern China.
    • The move was made with a view to boosting butterfly tourism and saving the species from extinction in the State.

    Other butterflies in news

    • The Malabar Banded Peacock or the Buddha Mayoori which was recently declared the ‘State Butterfly’ of Kerala will have a dedicated butterfly park in Kochi.
    • Tamil Nadu has also recently declared Tamil Yeoman (Cirrochroa Thais) as its state butterfly to symbolize its rich natural and cultural heritage.
    • Other states to have state butterflies are Maharashtra (Blue Mormon), Uttarakhand (Common peacock), Karnataka (Southern birdwings).

     

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  • Graded Response Action Plan (GRAP)

     

    States in the National Capital Region were directed to be ready to implement actions under the ‘emergency’ category of the Graded Response Action Plan (GRAP) to control air pollution, said an official order.

    Graded Response Action Plan (GRAP)

    • In 2014, when a study by the WHO found that Delhi was the most polluted city in the world, panic spread in the Centre and the state government.
    • Approved by the Supreme Court in 2016, the plan was formulated after several meetings that the Environment Pollution (Prevention and Control) Authority (EPCA) held with state government and experts.
    • The result was a plan that institutionalized measures to be taken when air quality deteriorates.
    • GRAP works only as an emergency measure.

    How does it work?

    • As such, the plan does not include action by various state governments to be taken throughout the year to tackle industrial, vehicular and combustion emissions.
    • When the air quality shifts from poor to very poor, the measures listed under both sections have to be followed since the plan is incremental in nature.
    • If air quality reaches the severe+ stage, GRAP talks about shutting down schools and implementing the odd-even road-space rationing scheme.

    Measures taken under GRAP

    1) Severe+ or Emergency

    (PM 2.5 over 300 ”g/cubic metre or PM10 over 500 ”g/cu. m. for 48+ hours)

    • Stop entry of trucks into Delhi (except essential commodities)
    • Stop construction work
    • Introduce odd/even scheme for private vehicles and minimise exemptions
    • Task Force to decide any additional steps including shutting of schools

    2) Severe

    (PM 2.5 over 250 ”g/cu. m. or PM10 over 430 ”g/cu. m.)

    • Close brick kilns, hot mix plants, stone crushers
    • Maximise power generation from natural gas to reduce generation from coal
    • Encourage public transport, with differential rates
    • More frequent mechanized cleaning of road and sprinkling of water

    3) Very Poor

    (PM2.5 121-250 ”g/cu. m. or PM10 351-430 ”g/cu. m.)

    • Stop use of diesel generator sets
    • Enhance parking fee by 3-4 times
    • Increase bus and Metro services
    • Apartment owners to discourage burning fires in winter by providing electric heaters during winter
    • Advisories to people with respiratory and cardiac conditions to restrict outdoor movement

    4) Moderate to poor

    (PM2.5 61-120 ”g/cu. m. or PM10 101-350 ”g/cu. m.)

    • Heavy fines for garbage burning
    • Close/enforce pollution control regulations in brick kilns and industries
    • Mechanized sweeping on roads with heavy traffic and water sprinkling
    • Strictly enforce a ban on firecrackers

    Has GRAP helped?

    • The biggest success of GRAP has been in fixing accountability and deadlines.
    • For each action to be taken under a particular air quality category, executing agencies are clearly marked.
    • In a territory like Delhi, where a multiplicity of authorities has been a long-standing impediment to effective governance, this step made a crucial difference.

     

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  • Recurring urban floods point to need for moving away from land-centric urbanism

    Context

    Flood in Chennai has revived memories of the devastating Chennai floods of 2015, a collective trauma that its residents are yet to outlive.

    Role of climate change

    • In August this year, as monsoon floods raged across the subcontinent, IPCC’s 6th Assessment Report (AR6) was published.
    • The report noted the increasing frequency of heavy precipitation events since the 1950s and inferred that they were being driven by human-induced climate change.
    • The climate crisis, is here.
    • It has made extreme rainfall events more severe and unpredictable than ever before.

    Role of poor planning and encroachment

    • In 2015, the National Green Tribunal in India formed a committee to report on the status of natural stormwater drains in Delhi.
    • On inspection, out of the 201 “drains” recorded in 1976, 44 were found to be “missing.
    • Geospatial imaging established that 376 km of natural storm drains — encroached on and paved over — had disappeared from Bengaluru.
    • In both cases, these “missing” waterways were either encroached and built over or connected to sewage drains.
    • Poor design and corruption significantly contribute to urban floods.
    • By violating environmental laws and municipal bye-laws, open spaces, wetlands and floodplains have been mercilessly built over, making cities impermeable and hostile to rainwater.

    Way forward

    • We need to move away from land-centric urbanisation and recognise cities as waterscapes.
    • We need to let urban rivers breathe by returning them to their floodplains.
    • The entire urban watershed needs to heal, and for that to happen, we need less concrete and more democracy and science at the grassroots.

    Conclusion

    Ever since concretisation became shorthand for urbanisation, rainfall in a changing climate no longer finds its way towards subterranean capillaries or surface water bodies.

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  • Earth’s first landmass emerged in Singhbhum: Study

    A new study has challenged the widely accepted view that the continents rose from the oceans about 2.5 billion years ago.

    About Singhbhum

    • Singhbhum district of Jharkhand is part of the Chhota Nagpur Division.
    • It is one of the leading producers of copper in India.

    First landmass to emerge

    • The study suggests that the earliest continental landmass to emerge may have been Jharkhand’s Singhbhum region.
    • Scientists have found sandstones in Singhbhum with geological signatures of ancient river channels, tidal plains and beaches over 3.2 billion years old.
    • They somewhat represent the earliest crust exposed to air.

    Studying the sandstones

    • The research studies a sedimentary rock, called granite. They tried to find their age and in which conditions they have formed.
    • They found the age by analysing the uranium and lead contents of tiny minerals.
    • These rocks are 3.1 billion years old, and were formed in ancient rivers, beaches, and shallow seas.
    • All these water bodies could have only existed if there was continental land.
    • Thus, they inferred that the Singhbhum region was above the ocean before 3.1 billion years ago.

    How did they analyse?

    • The researchers studied the granites that form the continental crust of Singhbhum region.
    • These granites are 3.5 to 3.1 billion years old and formed through extensive volcanism that happened about 35-45 km deep inside the Earth.
    • This process continued on-and-off for hundreds of millions of years until all the magma solidified to form a thick continental crust in the area.
    • Due to the thickness and less density, the continental crust emerged above surrounding oceanic crust owing to buoyancy.

    Back2Basics: Emergence of Landmass

    • In the beginning, more than 4.6-billion years ago, the world was a ball of burning gas, spinning through space.
    • It took hundreds of millions of years for the first land masses to emerge.
    • About 250-million years ago, long, long after the Earth had formed, all the continents of the time had joined together to form a super-continent called Pangaea.
    • This super-continent broke up about 200-million years ago to form two giant continents, Gondwana and Laurasia.
    • Gondwana comprised what is now Africa, South America, Australia, Antarctica and India.
    • The Indian sub-continent lay off the east coast of Africa, before it broke off and moved north rapidly.

    Isostacy

    • Huge plates of crustal and upper mantle material (lithosphere) “float” on more dense, plastically flowing rocks of the asthenosphere.
    • The “depth” to which a plate, or block of crust, sinks is a function of its weight and varies as the weight changes.
    • This equilibrium, or balance, between blocks of crust and the underlying mantle is called isostasy.
    • The taller a block of crust is, the deeper it penetrates into the mantle because of its greater mass and weight. Isostasy occurs when each block settles into an equilibrium with the underlying mantle.
    • Blocks of crust that are separated by faults will “settle” at different elevations according to their relative mass.

     

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