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Subject: Climate Change

1. Global Warming and Issues
2. All about Pollution

  • What are Marine Heat Waves (MHWs)?

    heat wave

    Central Idea

    • MHWs have engulfed regions like the northeast Pacific, southern Indian Ocean, the Atlantic, and the Mediterranean, as reported by Mercator Ocean International.
    • In April, the Sea Surface Temperature (SST) peaked at 21.1 degrees Celsius, breaking the previous record set in 2016.

    What are Marine Heat Waves (MHWs)?

    • While we often associate heatwaves with the atmosphere, they can also occur in the ocean, known as Marine Heatwaves (MHWs).
    • These prolonged periods of excessively warm sea surface temperatures (SST) can have significant consequences for marine ecosystems and industries.

      • SST is the temperature of the top layer of the ocean, typically measured at a depth of 1 millimeter to a few meters using buoys.

    • MHWs can happen in both summer and winter, with “winter warm-spells” affecting specific regions and species.

    How are MHWs measured?

    • Threshold Criteria: A marine heatwave is characterized by seawater temperatures exceeding a seasonally-varying threshold (often the 90th percentile) for at least 5 consecutive days.
    • Continuity of Events: Successive heatwaves with gaps of 2 days or less are considered part of the same MHW event.

    heat wave

    Causes of Marine Heatwaves

    • Air-sea heat flux: Ocean currents and air-sea heat flux are common drivers of MHWs, leading to the build-up of warm water in specific areas.
    • Influences of Wind and Climate Modes: Wind patterns can enhance or suppress MHWs. They influence the likelihood of events occurring in certain regions.
    • Large-Scale Climate Drivers: Events like the El Nino Southern Oscillation (ENSO) can also contribute to the formation of MHWs.
    • Intensification with Global Warming: Rising global temperatures have resulted in longer-lasting, more frequent, and intense MHWs in recent decades.
    • Human Influence: 87% of MHWs can be attributed to human-induced warming, with the oceans absorbing significant amounts of heat due to greenhouse gas emissions.
    • Oceans as Heat Sink: Oceans have absorbed 90% of the additional heat caused by greenhouse gas emissions, increasing global mean sea surface temperature by nearly 0.9 degrees Celsius since 1850.

    Impacts of Marine Heatwaves

    • Ecosystem Structure: MHWs can disrupt ecosystem structure, supporting certain species while suppressing others.
    • Kelp Forest Destruction: MHWs along the Western Australian coast in 2010-2011 devastated kelp forests and fundamentally altered the ecosystem of the coast.
    • Economic Losses: MHWs can cause economic losses, particularly in fisheries and aquaculture industries.
    • Vulnerability of Temperature-Sensitive Species: Species such as corals are highly vulnerable to MHWs. The 2016 marine heatwaves in northern Australia caused severe bleaching of the Great Barrier Reef.

    Impact on Marine Ecosystems

    • Catastrophic Effects: MHWs have led to the death of numerous marine species, altered migration patterns, and caused coral bleaching, endangering coral reefs.
    • Coral Bleaching: High ocean temperatures in the tropical Atlantic and Caribbean in 2005 led to a massive coral bleaching event, impacting over 80% of surveyed corals, with severe consequences for marine life.
    • Invasive Species and Ecological Imbalance: MHWs fuel the growth of invasive alien species, disrupting marine food webs and posing threats to wildlife. Ex. Whale entanglements in fishing gear.

    Consequences for Humans

    • Amplifying Storms: Higher ocean temperatures associated with MHWs make storms like hurricanes and cyclones stronger, leading to severe weather events and flooding.
    • Threat to Coral Reefs: Half a billion people depend on coral reefs for food, income, and protection, but MHWs pose a grave threat to these ecosystems, impacting human livelihoods.
    • Socio-Economic Impact: Coastal communities are particularly vulnerable to the socio-economic impacts of MHWs, affecting fisheries and tourism.

  • [pib] IMD launches Heat Index

    heat index

    Central Idea

    • Union Ministry of Earth Sciences informed that the India Meteorological Department (IMD) has introduced the Heat Index on an experimental basis.

    IMD Heat Index

    • The Heat Index aims to provide general guidance for regions in India where the combination of temperature and humidity leads to higher apparent temperatures, causing discomfort for people.
    • It is derived using an equation similar to the one used by the National Weather Service, National Oceanic and Atmospheric Administration (NOAA) in the USA.
    • It considers the impact of humidity on high temperatures, providing a “feel-like” temperature for human beings and indicating the level of discomfort.

    Color Codes for Experimental Heat Index

    The Heat Index is represented with different color codes to signify the varying levels of heat impact and discomfort:

    1. Green: Below 35°C
    2. Yellow: Range of 36-45°C
    3. Orange: Range of 46-55°C
    4. Red: Above 55°C

    Mitigating heat impact in India

    • The Heat Index is currently being implemented on an experimental basis across India, including Andhra Pradesh.
    • Under the Heat Action Plan, the National Disaster Management Authority (NDMA) collaborates with local agencies such as the Indian Institute of Public Health (IIPH) to implement the Heat Index project for Bhubaneshwar and Ahmedabad.

  • Places in news: Iriomote Island

    Central Idea

    • A notable example of colony resilience during a bleaching event is found near Japan’s Iriomote Island, where a colony bleached in 2016 exhibited signs of recovery by 2020.

    About Iriomote Island

    • Iriomote Island is a picturesque island located in the Yaeyama Islands, part of Okinawa Prefecture in Japan.
    • It is the largest and southernmost inhabited island in the Yaeyama archipelago.
    • With its lush jungles, mangrove forests, and diverse wildlife, Iriomote Island is often referred to as the “Galapagos of the East.”
    • It is home to the Iriomote Yamaneko, or Iriomote cat, which is a critically endangered species of wildcat found only on this island.
    • The dense mangrove forests along the island’s rivers and estuaries serve as an important habitat for numerous species of birds, fish, and other wildlife.
    • To preserve the island’s unique ecosystem and cultural heritage, Iriomote Island is part of the Iriomote-Ishigaki National Park.

    Back2Basics: Coral Reefs and Coral Bleaching

    coral

    • Corals are marine invertebrates that form colonies of polyps, which multiply and create reef structures.
    • Hard corals extract calcium carbonate to build hard exoskeletons, while soft corals add their skeletons to create coral reefs.
    • Corals have a mutually beneficial relationship with single-celled algae called zooxanthellae.
    • The zooxanthellae provide food and nutrients through photosynthesis, while corals provide a home and essential nutrients.
    • The zooxanthellae give corals their vibrant colors.

    Understanding Coral Bleaching

    • Causes of Bleaching: Environmental stressors like temperature changes, pollution, and high ocean acidity lead to coral bleaching.
    • Bleaching Process: Stressed corals expel the zooxanthellae, revealing their pale exoskeletons and disrupting the symbiotic relationship.
    • Impacts of Bleaching: Severe and prolonged bleaching events can result in coral death and the loss of biodiversity.

    Climate Change’s Impact on Coral Reefs

    • Warming Seas: Rising carbon emissions and greenhouse gases have caused increased global warming, resulting in warmer ocean temperatures.
    • Mass Bleaching: The frequency and intensity of mass bleaching events have risen in recent decades due to climate change.
    • Projections: Even with greenhouse gas reduction efforts, temperatures are expected to rise by 1.5°C to 2°C by the end of the century.

    Significance of Coral Reefs

    • Biodiversity Hotspots: Coral reefs support over 25% of marine biodiversity despite covering only 1% of the seafloor.
    • Economic Value: Reefs contribute $2.7 trillion annually through trade, tourism, and employment opportunities.
    • Environmental Protection: Coral reefs provide habitat and serve as a natural defense against storm waves.
    • Regeneration Potential: Dead reefs can recover if sufficient fish species graze on the weeds that settle on dead corals, although the process takes several years.

  • EV Tires: A lesser-known Pollution Headache

    tyre

    Central Idea: Tire Pollution

    • Meeting EVs’ Needs: Tire manufacturers strive to develop the perfect tire that balances performance and durability for electric vehicles (EVs).
    • Weight and Torque Considerations: EVs’ increased weight and torque require sturdier tires to handle the load and efficiently transfer power to the road.
    • Leading Manufacturers’ Efforts: Tire companies are improving designs and developing chemical formulas to meet the demands of EVs.

    Environmental Impact of Tires

    • Beyond Tailpipe Emissions: Tires significantly contribute to environmental degradation beyond exhaust emissions.
    • Tire Wear and Particle Shedding: Worn tires release tiny particles, which can become airborne or settle on soil, posing risks to air and land quality.
    • Microplastic Pollution: Tire particles entering waterways contribute to the growing problem of microplastic pollution.
    • VOCs and Smog: Tires contain volatile organic compounds (VOCs) that react in the atmosphere, contributing to smog formation and air pollution.

    Tire Emissions and Electric Vehicles

    • Surpassing Tailpipe Emissions: Tire particulate pollution has exceeded emissions from vehicle tailpipes.
    • EVs’ Weight Impact: EVs’ additional weight results in higher tire wear emissions compared to traditional vehicles.
    • Tesla Model Y vs. Kia Niro: A study showed that the Tesla Model Y exhibited 26% greater tire wear emissions than the Kia Niro.

    Environmental Hazards and Solutions

    • Water Pollution and Microplastics: Tire particulate pollution contributes to water pollution and the accumulation of microplastics.
    • Health Hazards and 6PPD: The chemical 6PPD in tires poses risks to aquatic life, edible plants, and human health.
    • Balancing Climate Goals and Tire Emissions: Addressing tire emissions is crucial when transitioning to electric vehicles to mitigate overall pollution levels.
    • Reducing Car Use vs. Economic Activity: Balancing environmental concerns and economic activity while reducing car usage is essential for sustainable mobility.

    Market Mechanisms and Individual Actions

    • Incentivizing Innovation: Market mechanisms can encourage tire companies to invest in developing low-emission tire formulations.
    • VOC Toxicity Variations: Stricter industry standards are needed to regulate volatile organic compound (VOC) toxicity levels in tires.
    • Individual Actions for Tire Wear Reduction: Responsible driving habits can reduce tire wear and particulate emissions.
    • Maximizing Lifespan: Using tires to their full lifespan minimizes particulate emissions during the initial usage period.

    Conclusion

    • Innovating for a Sustainable Future: Tire design and manufacturing must balance EV performance and pollution reduction.
    • Collaborative Efforts Needed: Market, industry, and individual actions are crucial to address tire and EV-related challenges.
    • Striving for Sustainable Mobility: Comprehensive solutions integrating technology, environmental considerations, and responsible behavior can mitigate the environmental impact of tires.

  • EU Nature Restoration Law faces backlash from Farmers

    eu nature restoration

    Central Idea

    • The EU Parliament’s approval of a nature restoration law has sparked backlash and debate over plans to protect endangered ecosystems.
    • The law is a crucial part of the European Green Deal and aims to address the extinction of species and restore damaged habitats.

    Nature Restoration Law: Why in news?

    • Objectives: The law aims to restore 30% of terrestrial, coastal, freshwater, and marine habitats by 2030, which are currently in poor condition.
    • Resistance: Farmers and conservative lawmakers strongly oppose the legislation, particularly concerning plans to restore drained peatlands. They argue that valuable agricultural land may be lost, leading to economic and social consequences and potential food security risks.

    Importance of Peatlands and Environmental Impact

    • Peatland Carbon Storage: Peatlands, wetland ecosystems formed over thousands of years, store more carbon than any other ecosystem. They absorb nearly twice as much carbon dioxide as all of the Earth’s forests combined.
    • Drained Peatlands: When peatlands are drained for agriculture or other purposes, they transition from being carbon sinks to significant greenhouse gas sources, contributing to emissions.
    • European Peatlands: More than half of Europe’s peatlands have been permanently damaged, leading to approximately 7% of the continent’s greenhouse gas emissions.

    Calls for Rewetting and Paradigm Shift

    • Rewetting Peatlands: The proposed legislation includes plans to rewet 50% of former peatlands in Europe, aiming to restore their environmental functions and mitigate climate change.
    • Paradigm Shift in Agriculture: Experts advocate for a paradigm shift in agriculture, moving away from farming on drained peatlands and investing in paludiculture (farming on wetlands), which is agriculture on rewetted peat soil. This approach would stop carbon emissions while improving soil and water quality.

    Political Challenges and Compromises

    • Opposition by Conservative Groups: Conservative groups, including the European People’s Party, seek to reduce the scope of wetland restoration plans and oppose the conversion of agricultural land.
    • Concerns and Dissemination of Misinformation: Critics claim that villages could be cleared for wetland restoration, leading to economic and social fallout. However, these claims have been labeled as misinformation and populist.

    Economic and Environmental Benefits

    • Long-Term Economic Return: The European Commission estimates that every euro invested in restoring natural resources would yield at least eight times the economic return over the long term.
    • Sustainable Land Use: While rewetted land may not support traditional monocultures, it could enable the growth of other crops, such as timber, grasses, and reeds for insulation materials and organic plastic substitutes. Revitalized areas could also become grazing grounds for alternative livestock.

    Conclusion

    • The approval of the EU nature restoration law has sparked a debate between environmental conservation and agricultural interests.
    • While farmers express concerns over the potential loss of agricultural land and economic impact, environmentalists argue for the restoration of threatened ecosystems and the long-term benefits of sustainable land use.
    • The implementation of the law will play a crucial role in achieving the ambitious climate and biodiversity targets set by the European Green Deal.

     

  • Just Energy Transition Partnership (JETP)

    just energy

    Central Idea

    • Senegal has joined the Just Energy Transition Partnership (JETP) deal, becoming the fourth country to sign after South Africa, Indonesia, and Vietnam.
    • The deal aims to mobilize 5 billion euros in new financing for Senegal.

    What is Just Energy Transition Partnership (JETP)?

    • JETP is a financing mechanism that aims to support developing countries in their transition from fossil fuel-based energy systems to clean and renewable energy sources.
    • JETP is designed to bridge the gap between wealthier nations and coal-dependent developing nations, addressing both the environmental and social aspects of the energy transition.

    JETP Mechanism and Social Considerations

    • JETPs provide financing to developing countries to phase out coal and transition to clean energy.
    • Social aspects, such as protecting affected communities and providing job opportunities, are crucial in JETP plans.
    • Reskilling, upskilling, and creating new jobs are essential components of a just energy transition.

    Funding Sources and Donor Pool

    • JETP funding can be provided through grants, loans, or investments.
    • The International Partners Group (IPG) and the Glasgow Financial Alliance for Net Zero (GFANZ) Working Group are key contributors.
    • The IPG includes countries such as Japan, the USA, Canada, Denmark, France, Germany, Italy, Norway, the EU, and the UK.
    • The GFANZ Working Group comprises multilateral and national development banks and finance agencies.

    JETP Success Stories

    • South Africa was the first country to enter into a JETP at COP 26 Glasgow, with a pledge of 8.5 billion USD in financing.
    • Indonesia announced its JETP at the G20 Bali Summit, receiving an initial 20 billion USD in public and private financing.
    • Vietnam joined the JETP initiative, securing an initial fund of 15.5 billion USD over the next three to five years.

    Prospects for India’s Participation

    • Talks of a JET-P deal with India are ongoing but have not reached a final conclusion.
    • Challenges include the complexity of India’s coal-based power sector and financing in the form of loans.
    • India seeks favorable conditions and no compromise on energy security and development.

  • New Collective Quantified Goal (NCQG) in Climate Financing

    bonn climate

    Central Idea

    • The New Collective Quantified Goal (NCQG) has emerged as a significant commitment in global climate financing at the recently-concluded Bonn climate conference in Germany.
    • The conference, which sets the stage for the upcoming Conference of Parties-28 (COP28) in Dubai, has exposed significant gaps in funding for climate action.

    Conference of Parties (COP)

    • The Conference of Parties (COP) is a key international event where countries come together to address the urgent challenges posed by climate change.
    • It is the supreme decision-making body of the United Nations Framework Convention on Climate Change (UNFCCC).
    • The COP brings together representatives from various countries to assess progress, negotiate agreements, and establish international climate policies and commitments.
    • The first COP took place in 1995 in Berlin, Germany, following the adoption of the UNFCCC in 1992.
    • Since then, the COP has been held annually, with each event designated by a specific number (e.g., COP21, COP22) indicating the sequential order.

     

    What is New Collective Quantified Goal (NCQG)?

    • The commitment of $100 billion per year till 2020 to developing nations by developed countries was set at the 2009 COP.
    • The cost estimates for addressing climate change indicate that billions, and possibly trillions, of dollars are required.
    • The 2015 Paris Climate Agreement emphasized the need for a NCQG for climate financing before 2025.
    • The NCGQ aims to account for the needs and priorities of developing nations and has been termed the “most important climate goal.”
    • It should reflect scientific evidence, respond to increased funding requirements for Loss and Damage, and involve developed countries increasing their commitments.

    Need for NCQG

    • Developed countries provided $83.3 billion in 2020 out of the promised $100 billion per year.
    • However, an analysis by Oxfam suggests that these figures may be inflated by as much as 225% due to misleading and dishonest reporting.
    • The $100 billion target set in 2009 lacked clarity in terms of the definition and source of ‘climate finance.’

    Challenges and Concerns

    (A) Accessibility and Sustainability of Climate Finance

    • While the funds for climate finance have increased, they remain largely inaccessible to developing countries.
    • The majority of climate finance comes in the form of loans and equity, burdening developing nations with a debilitating debt crisis.
    • Only around 5% of climate finance is provided as grants, which severely limits the capacity of countries in need.

    (B) Developed Countries’ Perspective

    • Developed countries argue that the NCQG should be seen as a collective goal for all countries.
    • This perspective places the burden of mitigation, adaptation, and loss and damage on developing countries.
    • Experts raise concerns that developing nations may struggle to bear the costs while also ensuring sustainable infrastructure development.
    • Developed countries advocate for mobilizing private-sector investments and loans as a critical component of climate finance.

    Future roadmap

    • A deadline looms for countries to agree on the NCQG before 2024.
    • While there is no official figure yet, estimates suggest that transitioning to a low-carbon economy requires annual investments of $4 trillion to $6 trillion.
    • Some propose setting separate targets or sub-goals for focus areas like mitigation, adaptation, and loss and damage instead of a single aggregate figure.
    • The focus should be on scaling up concessional financing, halting debt creation, and transforming the NCQG into an equitable and people-led transition process.

  • Blue Ocean Event: Arctic Ocean to be Ice-Free by 2030s

    blue ocean

    Central Idea

    • A new study published in Nature Communications warns that the Arctic Ocean could be ice-free in summer by the 2030s, even with significant emission reduction efforts.
    • This alarming conclusion challenges previous predictions and highlights the global, damaging, and dangerous consequences of such a scenario.

    Accelerated Climate Heating in the Arctic

    • Fastest Heating: The Arctic region has been experiencing climate heating at a faster rate than any other part of the planet, making it a frontline area for climate change.
    • Focus on Sea Ice: Scientists and local indigenous communities closely monitor the sea ice that covers much of the Arctic Ocean during winter, as it is a critical indicator of climate change.
    • Diminishing Sea Ice: Over the past 40 years, multiyear sea ice, which remains at the end of summer, has reduced from approximately 7 million sq. km to 4 million sq. km, representing a significant loss.

    Predicting an Ice-Free Arctic: Blue Ocean Event

    • What is it: Scientists have been studying when the Arctic Ocean might become ice-free in summer, known as a “blue ocean event,” defined by the sea ice area dropping below 1 million sq. km.
    • Complex Modeling: Sea ice is challenging to model accurately due to its sensitivity to atmospheric and oceanic circulation and heat transfer. Previous climate models underestimated the loss of sea ice compared to actual observations.
    • Observationally Constrained Projections: The latest study takes a calibrated approach, using observational data to refine the models and project sea ice decline. It suggests the Arctic could become ice-free in summer as early as the 2030s, even with emission reductions.

    Implications of an Ice-Free Arctic:

    • Climate Feedback: The loss of Arctic sea ice amplifies warming through positive feedback, as it reduces sunlight absorption by the ocean, potentially accelerating the melting of the Greenland ice sheet and contributing to sea-level rise.
    • Environmental Shifts: An ice-free Arctic would lead to changes in atmospheric circulation, storm tracks, and ocean biological activity, with far-reaching and undesirable consequences.
    • Slender Benefits: While there may be some perceived benefits, such as shorter shipping routes, they pale in comparison to the negative impacts on the climate system and global ecosystems.

    Conclusion

    • The potential ice-free Arctic Ocean by the 2030s, as indicated by the study, underscores the urgent need for climate action.
    • The consequences of such a scenario extend far beyond.
    • The study highlights the imperative of mitigating climate change to avoid further damage to the Arctic and the planet as a whole.

  • Bonn Climate Conference: Key Takeaways

    bonn climate

    Central Idea

    • The Bonn Climate Change Conference was held from 5 to 15 June 2023.
    • Building on the mandates that emerged from COP 27 in Egypt last year, the conference hosted a large number of mandated events and continue discussions on issues of critical importance.
    • It is expected to make progress on these and other important issues and prepare draft decisions for adoption at COP 28 / CMP 18 / CMA 5 in the UAE in December 2023.

    Key ideas discussed

    • Some progress was made on the global stocktake (GST) discussions.
    • However, the issues of historical responsibility and finance remained contentious, hindering the strengthening of climate actions.

    climate

    What is Global Stocktake (GST)?

    • GST is a process established under the 2015 Paris Agreement on climate change.
    • It serves as a mechanism to assess global progress in addressing climate change and to enhance collective climate action.
    • The GST aims to review the implementation of the Paris Agreement’s goals and targets and identify areas where additional efforts are needed to meet those objectives.

    Key aspects of the Global Stocktake include:

    1. Timing: The Paris Agreement mandates that the GST be conducted every five years, starting in 2023. This regular assessment allows for tracking progress and adjusting strategies accordingly.
    2. Assessment of Collective Efforts: GST evaluates the collective efforts of all countries in reducing greenhouse gas emissions, adapting to the impacts of climate change, and providing support to developing nations.
    3. Review of Goals and Targets: It assesses the effectiveness of countries’ actions in meeting the long-term temperature goals outlined in the Paris Agreement, primarily the goal to limit global warming to well below 2 degrees Celsius above pre-industrial levels, and to pursue efforts to limit the temperature increase to 1.5 degrees Celsius.
    4. Transparency and Accountability: The GST promotes transparency and accountability by encouraging countries to report on their progress and actions taken toward achieving their climate goals. This allows for a comprehensive and objective assessment of global climate action.
    5. Identification of Gaps and Opportunities: The stocktake identifies gaps in collective efforts, including finance, technology transfer, and capacity-building support, and explores opportunities for enhanced actions to bridge those gaps.
    6. Decision-Making: The findings and recommendations from the GST inform future decision-making, including the setting of new targets and the adjustment of national climate plans, known as Nationally Determined Contributions (NDCs).

    Challenges in Climate Negotiations

    • Disputes and Delayed Agendas: Developed and developing countries engaged in disagreements, leading to delays in agreeing on meeting agendas.
    • Historical Responsibility Debate: Australia’s attempt to diminish the historical responsibility of developed nations in causing global warming sparked controversy.
    • Developing Countries’ Perspective: Developing nations emphasized the importance of acknowledging historical responsibility in addressing climate change.
    • Potential Conflict at COP28: The issue of historical responsibility is expected to resurface at COP28, posing challenges to reaching consensus.

    Finance and Technology Transfer

    • Disparity in Support: Developing countries expressed concerns about inadequate financial and technological support from developed nations.
    • Burden of Implementation: Insufficient funds hinder the ability of developing countries to implement robust climate action plans.

    Future Outlook

    (1) Bridging Adequacy Gap:

    • Developed Nations’ Perspective: Australia and the United States questioned the sole responsibility of developed countries in bridging the adequacy gap.
    • Developing Nations’ Concerns: Developing countries emphasized the need for financial support and technology transfers to enhance their climate actions.
    • Value Addition: Bridging the adequacy gap requires global cooperation, equitable burden-sharing, and increased financial assistance for developing countries.

    (2) Financing Climate Action:

    • Insufficient Funds: Current financial commitments fall short of the required resources for implementing climate action plans.
    • Summit for a New Global Financial Pact: A Paris summit aims to redirect global financial flows and raise new funds for climate change initiatives.

  • Groundwater Extraction Shifts Earth’s Tilt Axis

    earth tilt

    Central Ideas

    • A recent study conducted by scientists at Seoul National University has revealed that the extraction of groundwater from the earth has caused a shift in the planet’s axis, tilting it nearly 80 cm to the east.
    • This phenomenon, along with the movement of water through melting ice caps and glaciers, has implications for both the earth’s rotation, sea-level rise, and the distribution of water resources.

    Earth’s Axis and Rotation

    • The Earth’s axis and rotation play significant roles in shaping our planet’s climate, seasons, and day-night cycles.
    • Here are some key points about Earth’s axis and rotation:
    1. Axis: The axis is an imaginary line that extends between the North Pole and the South Pole and is tilted at an angle of approximately 23.5 degrees relative to its orbital plane around the Sun. This tilt is responsible for Earth’s seasons.
    2. Rotation: Earth rotates on its axis from west to east, completing one full rotation in approximately 24 hours. This rotation is what gives us the cycle of day and night. The side of the Earth facing the Sun experiences daylight, while the opposite side experiences darkness, resulting in day and night.
    3. Polar Regions: The axis of the Earth is inclined with respect to its orbital plane. This inclination causes the Polar Regions to experience variations in daylight throughout the year. During the summer solstice (around June 21), the North Pole is tilted towards the Sun, resulting in 24 hours of continuous daylight in the Arctic Circle and 24 hours of darkness in the Antarctic Circle. The opposite occurs during the winter solstice (around December 21).
    4. Equator: The equator is an imaginary line equidistant from the poles and divides the Earth into the Northern Hemisphere and the Southern Hemisphere. The equator experiences relatively consistent day and night lengths throughout the year, with two equinoxes occurring when the Sun is directly above the equator. During the equinoxes (around March 21 and September 21), day and night are approximately equal in length worldwide.
    5. Precession (Cyclic Wobble): In addition to its axial tilt, Earth experiences a slow, cyclic wobble called precession. This wobble causes the orientation of Earth’s axis to change slightly over a period of approximately 26,000 years. Precession does not affect the tilt or the length of the seasons but does influence the positions of the celestial poles and the timing of Earth’s closest approach to the Sun (perihelion) and farthest point (aphelion).

    Why in news?

    • Unlike a stable rotating globe, the earth’s axis experiences a wobble due to various factors such as weather, seasonal changes, the molten core, and natural events like hurricanes.
    • Scientists track this motion relative to astronomical phenomena, but the role of water movement, including groundwater extraction, had not been fully considered until now.
    • The earth’s axis wobbles in a circular pattern several meters wide every year.

    Study Findings

    • Researchers at Seoul National University built a climate model linking the earth’s axis shift with water movement, including the melting of ice caps and glaciers.
    • Initially, the model did not match the observed drift of the axis until groundwater extraction was added to the equation.
    • Groundwater pumping accounted for the unexplained cause of the rotation pole drift.
    • The shift in the earth’s axis due to groundwater extraction was measured at nearly 80 cm tilt to the east.

    Implications for Sea-Level Rise

    • The study revealed that approximately 2,150 billion tonnes of groundwater were pumped and drained into the oceans between 1993 and 2010, contributing to a sea-level rise of 6.24 mm.
    • Groundwater depletion plays a significant role in the location and magnitude of the axis drift.
    • Mid-latitude regions, particularly northwest India and western North America, showed the most significant groundwater redistribution effects.

    Impact on Water Resources

    • Groundwater extraction for human activities, including irrigation, is affecting the distribution and availability of water resources.
    • Excessive groundwater pumping has led to a significant redistribution of water, altering the balance between surface water and groundwater reserves.