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Subject: Climate Change

1. Global Warming and Issues
2. All about Pollution

  • What is Carbon Border Adjustment Mechanism (CBAM)?

    carbon

    The Indian government will be analyzing how the European Union’s (EU’s) proposed carbon border adjustment mechanism (CBAM) will affect the Indian industry. The CBAM is set to start from October this year.

    Carbon Border Adjustment Mechanism (CBAM)

    Proposed by European Union (EU)
    Purpose To reduce carbon emissions from imported goods and prevent competitive disadvantage against countries with weaker environmental regulations
    Objectives Reduce carbon emissions from imported goods

    Promote a level playing field between the EU and its trading partners

    Protect EU companies that have invested in green technologies

     

    How does CBAM work?

    Coverage Applies to imported goods that are carbon-intensive
    Integration Covered by the EU’s Emissions Trading System (ETS), which currently covers industries like power generation, steel, and cement
    Implementation CBAM taxes would be imposed on the carbon content of imported goods at the border, and the tax rates would be based on the carbon price in the EU ETS
    Exemptions Possible exemptions for countries that have implemented comparable carbon pricing systems
    Revenue Use Revenue generated from CBAM taxes could be used to fund the EU’s climate objectives, such as financing climate-friendly investments and supporting developing countries’ climate efforts

     

    Who will be affected by CBAM?

    Details
    Countries Non-EU countries, including India, that export carbon-intensive goods to the EU
    Items Initially covers iron and steel, cement, aluminium, fertilisers, and electric energy production
    Expansion The scope of the CBAM may expand to other sectors in the future

    Advantages of CBAM

    • Encourages non-EU countries to adopt more stringent environmental regulations, reducing global carbon emissions.
    • Prevents carbon leakage by discouraging companies from relocating to countries with weaker environmental regulations.
    • Generates revenue that could be used to support EU climate policies.

    Challenges with CBAM

    • Difficulty in accurately measuring the carbon emissions of imported goods, especially for countries without comprehensive carbon accounting systems.
    • Potential for trade tensions with the EU’s trading partners, especially if other countries implement retaliatory measures.

    Conclusion

    • The CBAM is a proposed policy by the EU to reduce carbon emissions from imported goods and to promote a level playing field between the EU and its trading partners.
    • Although the CBAM has its challenges, it has the potential to incentivize non-EU countries to adopt more stringent environmental regulations and reduce global carbon emissions.

     

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  • Oceans absorb 90% of human-induced planet warming: Study

    ocean

    The study published in the journal Earth System Science Data estimates that almost 90% of the warming that has occurred in the last 50 years has been absorbed by the ocean, with the remaining heat absorbed by the land, cryosphere and atmosphere.

    Earth’s energy balance: A quick recap

    ocean

    • It is the balance between the amount of energy that Earth receives from the Sun and the amount of energy that Earth radiates back into space.
    • It is also known as the radiation budget.
    • The energy from the Sun that Earth receives is mainly in the form of visible light and ultraviolet radiation.
    • This energy is absorbed by the Earth’s surface and atmosphere, which then radiate it back into space in the form of infrared radiation.
    • The balance between incoming and outgoing radiation is crucial for maintaining the Earth’s temperature and climate.
    • Any imbalance between the two can lead to global warming and climate change.
    Description
    Total incoming solar radiation Approximately 342 W/m² reaches Earth’s atmosphere
    Albedo About 30% of incoming solar radiation is reflected back to space
    Greenhouse effect Remaining 70% of incoming solar radiation is absorbed by Earth’s surface and atmosphere, creating the greenhouse effect
    Atmospheric heat Atmosphere contains only 0.001% of Earth’s heat energy, but is crucial in regulating heat budget

     

    Key highlights of the Study: Heat Accumulation

    heat

    • The study estimates that approximately 381 zettajoules (ZJ) of heat accumulated on the planet from 1971-2020 due to anthropogenic emissions.
    • This roughly equals a heating rate of approximately 0.48 watts per square metre (Earth Energy Imbalance or EEI). EEI is the difference between incoming and outgoing solar radiation.
    • According to the study, about 89% of the accumulated heat is stored in the ocean, 6% on land, a percent in the atmosphere, and about 4% available for melting the cryosphere.

    Implications

    (1) Land Heat Accumulation

    • Heat accumulated on land drives up ground surface temperatures, which may increase soil respiration, releasing carbon dioxide in the process.
    • Higher soil respiration will likely decrease soil water, depending on climatic and meteorological conditions and factors.

    (2) Inland Water Bodies and Permafrost Thawing

    • Heat storage within inland water bodies has increased to roughly 0.2 ZJ since 1960. For permafrost thawing, it was about 2 ZJ.
    • The accumulation of heat in inland water increases lake water temperatures, making conditions ripe for algal blooms.
    • Permafrost heat content could inject methane and carbon dioxide into the atmosphere, the researchers warned.

    (3) Ocean and Troposphere heating

    • The upper ocean (0-300 and 0-700 meters depth) has taken up a major fraction of heat, according to the new estimates.
    • During 2006-2020, ocean warming rates for the 0-2,000 meters depth reached record rates of roughly 1.03 watts per square meter.
    • The troposphere is also warming up due to increased heat accumulation.

    (4) Cryosphere heating

    • The cryosphere – the frozen water part of the Earth system – gained roughly 14 ZJ of heat from 1971-2020.
    • Half of the uptake triggered the melting of grounded ice, while the remaining half is linked to the melting of floating ice.
    • The Antarctic Ice Sheet contributed about 33% to the total cryosphere heat gain, while Arctic sea ice stood second, having contributed 26%.

     

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  • Bioluminescence observed at Visakhapatnam beach

    bio

    The blooms of Noctiluca Scintillans, commonly known as “sea sparkle or bioluminescence” are being witnessed along the coasts of Visakhapatnam, AP.

    Noctiluca Scintillans

    • Scintillans is a bioluminescent specie that brightens the seawater during the night.
    • It grazes on other micro-organisms such as larvae, fish eggs, and diatoms. But the unicellular phytoplankton that lives inside it can photosynthesize, turning sunlight into energy.
    • They help their host cell survive even when food was scarce.
    • Thus, N. Scintillans acts as both a plant and an animal

    Threats posed

    • According to marine experts, the phenomenon is an indicator of climate change.
    • While smaller blooms may be harmless, slow-moving larger blooms may have an impact on deep-sea fishes.
    • The toxic blooms of N. Scintillans were linked to massive fish and marine invertebrate kills.
    • Though the species does not produce a toxin, it was found to accumulate toxic levels of ammonia, which is then excreted into the surrounding waters, possibly acting as the killing agent in blooms.
    • They have displaced microscopic algae called diatoms, which form the basis of the marine food chain. This has deprived food for the planktivorous fish.

    Back2Basics: Bioluminescence

    • It is the property of a living organism to produce and emit light.
    • Animals, plants, fungi and bacteria show bioluminescence. A remarkable diversity of marine animals and microbes are able to produce their own light.
    • It is found in many marine organisms such as bacteria, algae, jellyfish, worms, crustaceans, sea stars, fish and sharks.
    • Luminescence is generally higher in deep-living and planktonic organisms than in shallow species.

     

  • IMD predicts normal monsoon despite El Nino effect

    nino

    Central idea

    • India’s four-year run of abundant summer monsoon rainfall is likely to end this year, with the India Meteorological Department (IMD) forecasting a 4% shortfall in the coming season.
    • The monsoon forecast for 2022 is still categorized as “normal” but at 96% of the long-period average (LPA), it is at the lowest end of the range.
    • El Nino, a cyclical phenomenon of warming in the central Pacific, is believed to be the key factor responsible for the below-normal forecast.

    Factors affecting the forecast

    • El Nino: It has been linked to diminished rainfall in six out of 10 years in India, and 2022 is expected to see its development.
    • La Nina: It has been influencing the rainfall in India since 2019 and is expected to end this year.
    • Reduced snow cover in Eurasia: It can have a positive impact on the monsoon forecast, and this year’s snow cover in Eurasia was below normal.
    • Positive phase of the Indian Ocean Dipole (IOD): IOD could result in more moisture and rainfall over India during August and September, and therefore, have a reduced impact of the El Nino.
    • IMD’s dynamical monsoon forecast techniques: It involves the simulation of global atmospheric and ocean conditions to forecast climate conditions, which the IMD has started to rely on more heavily in recent years.

    What is El Nino and La Nina?

    • El Nino and La Nina are two opposite phases of the El Nino-Southern Oscillation (ENSO) cycle.
    • ENSO is a naturally occurring phenomenon that involves the interaction between the ocean and atmosphere in the equatorial Pacific.

    Here is a detailed comparison of El Nino and La Nina

    El Nino La Nina
    Definition Warmer-than-normal sea surface temperatures Cooler-than-normal sea surface temperatures
    Frequency Every two to seven years Every two to seven years
    Duration Several months to a year or more Several months to a year or more
    Impact on winds Weakens trade winds, leading to changes in patterns Strengthens trade winds, leading to changes in patterns
    Impact on rains Reduces rainfall and can cause droughts Increases rainfall and can cause flooding
    Impact on temp. Warmer-than-average temperatures Colder-than-average temperatures
    Global effects Droughts in Asia and Africa, floods in Americas Floods in Asia and Africa, droughts in South America

     

    Impacts on India

    El Nino La Nina
    Associated with weak monsoons and drought-like conditions in India Associated with above-normal rainfall and floods in India
    Sea surface temperature in the equatorial Pacific Ocean rises above normal levels Sea surface temperature in the equatorial Pacific Ocean drops below normal levels
    Changes in the atmospheric circulation patterns Changes in the atmospheric circulation patterns
    Shift in the location of the jet stream, affecting the strength and direction of the monsoon winds Increase in the strength of the monsoon winds, bringing more moisture and rainfall to India
    Results in reduced rainfall, dry spells, and heatwaves, leading to crop failures and water scarcity Excessive rainfall can also lead to floods and landslides, causing damage to crops and infrastructure

     

    Back2Basics: Long Period Average (LPA) study of Monsoon

    • The IMD predicts a “normal”, “below normal”, or “above normal” monsoon in relation to a benchmark “long period average” (LPA).
    • The LPA of rainfall is the rainfall recorded over a particular region for a given interval (like month or season) average over a long period like 30 years, 50 years, etc.
    • LPA refers to the average rainfall recorded from June to September for the entire country, the amount of rain that falls every year varies from region to region and from month to month.
    • The IMD’s prediction of a normal monsoon is based on the LPA of the 1971-2020 period, during which India received 87 cm of rain for the entire country on average.
    • It has in the past calculated the LPA at 88 cm for the 1961-2010 period, and at 89 cm for the period 1951-2000.

    IMD Rainfall Distribution Categories

    Rainfall Distribution Categories Percentage Departure of Actual Rainfall from LPA
    Normal or Near Normal +/- 10% of LPA (between 96-104% of LPA)
    Below Normal Less than 10% of LPA (90-96% of LPA)
    Above Normal 104-110% of LPA
    Deficient Less than 90% of LPA
    Excess More than 110% of LPA

     

  • Arctic scientists race to preserve ‘Ice Memory’

    snap

    Scientists from Italy, France, and Norway have set up camp in Norway’s Svalbard archipelago to extract samples of ancient ice for analysis before the frozen layers melt away due to climate change.

    ‘Ice Memory’ Project

    • Scientists will drill a series of tubes as far as 125 meters (137 yards) below the surface, which contains frozen geochemical traces dating back three centuries.
    • The scientists will work for three weeks in temperatures as low as -25 degrees Celsius (-13 Fahrenheit) to extract ice.
    • The Ice Memory foundation is running the operation.
    • The ice cores will provide scientists with valuable data about past environmental conditions.

    Analysis and storage

    • One set of ice tubes will be used for immediate analysis, while a second set will be sent to Antarctica for storage in an “ice memory sanctuary” under the snow.
    • The samples will be preserved for future generations of scientists.

    Reason for drilling

    • The Arctic is warming between two and four times faster than the global average, and water from melting ice is altering the geochemical records preserved in ancient ice beneath.
    • Hence, scientists are in a race against time to preserve crucial ice records before it disappears forever from the surface of the planet.

  • ICJ and Climate Justice

    Central idea: On March 29, the United Nations General Assembly passed a resolution that requested an advisory opinion from the International Court of Justice (ICJ) regarding the obligations countries have towards climate change reduction.

    Facts for prelims: International Court of Justice (ICJ)

    • The ICJ is the principal judicial organ of the United Nations (UN).
    • It was established in June 1945 by the Charter of the United Nations and began work in April 1946.
    • The court is the successor to the Permanent Court of International Justice (PCIJ), which was brought into being through, and by, the League of Nations.
    • It held its inaugural sitting at the Peace Palace in The Hague, Netherlands, in February 1922.
    • After World War II, the League of Nations and PCIJ were replaced by the United Nations and ICJ respectively.
    • The PCIJ was formally dissolved in April 1946, and its last president, Judge José Gustavo Guerrero of El Salvador, became the first president of the ICJ.
    • Four Indians have been members of the ICJ so far.
    • Justice Dalveer Bhandari, former judge of the Supreme Court, has been serving at the ICJ since 2012.

     

    Vanuatu seeks climate reparations

    • The resolution, which was passed by consensus, was pushed through by the Pacific Island of Vanuatu, which was devastated by Cyclone Pam in 2015.
    • This resolution is significant because it invokes article 96 of the U.N. Charter and seeks to clarify the legal obligations of states to protect the climate system.

    Resolution A/77/L.58: What does it seek?

    The draft resolution (A/77/L.58) asks the ICJ to deliberate on two questions:

    1. Obligations of states: Under international law to ensure the protection of the climate system for present and future generations
    2. Legal consequences: For states that have caused significant harm to the climate system, particularly for Small Island Developing States (SIDS) and for people who are harmed?

    Frameworks invoked by Vanuatu

    The resolution refers to several international protocols, including the-

    1. Paris Agreement
    2. United Nations Convention on the Law of the Sea and
    3. Universal Declaration of Human Rights

    What do sponsors of the resolution want?

    • The sponsors of the resolution expect an advisory opinion from the ICJ to bolster the efforts under the global climate pledge.
    • The opinion is also expected to clarify more contentious issues, such as-
    1. Climate reparations by the developed world,
    2. Legal culpability for countries that don’t achieve their NDC promises
    3. Climate support to the most vulnerable parts of the world

    Where does India stand over this?

    • India has been silent about the resolution, although it is generally supportive of climate justice and holding the developed world accountable for global warming.
    • India did not co-sponsor the draft resolution, unlike its neighbors Bangladesh, Maldives, Nepal, and Sri Lanka.

    If ICJ intervenes, what would change?

    • Only advisory opinion: The ICJ is being asked for an advisory opinion, which would not be legally binding as an ICJ judgment.
    • Puts moral obligation: The ICJ carries “legal weight and moral authority”.
    • Symbolic significance: ICJ’s clarification of international environmental laws would make the process more streamlined, particularly as the COP process looks at various issues like climate finance, climate justice, and the most recently agreed to “loss and damages” etc.

    Conclusion

    • The resolution passed by the UNGA requesting an advisory opinion from the ICJ is a step in the right direction towards clarifying the legal obligations of states to mitigate climate change and protect the environment for future generations.
    • To ensure the success of this effort, countries need to continue to engage in diplomatic efforts and work towards shared goals.
    • Countries should also actively participate in the ICJ process and respect the advisory opinion it delivers.

  • Key takeaway of the IPCC Synthesis Report

    ipcc

    The IPCC Synthesis Report warns that the world is on track to breach the 1.5-degree Celsius global warming limit by the 2030s, which would cause irrevocable damage to the planet’s ecosystem and severely impact humans and other living beings.

    What is IPCC Synthesis Report?

    • The IPCC Synthesis Report is a summary report produced by the Intergovernmental Panel on Climate Change (IPCC) that presents key findings and policy recommendations from the group’s previous assessment reports.
    • It aims to provide policymakers with a concise overview of the current state of knowledge on climate change, its impacts, and options for mitigation and adaptation.
    • The Synthesis Report is released at the end of each assessment cycle, which typically takes six to seven years, and is approved by representatives from the IPCC’s member governments.

    Intergovernmental Panel on Climate Change (IPCC)

    • The IPCC, an intergovernmental body was established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP).
    • It was later endorsed by the UN General Assembly. Membership is open to all members of the WMO and UN.
    • The IPCC produces reports that contribute to the work of the UN Framework Convention on Climate Change (UNFCCC), the main international treaty on climate change.

     

    Key highlights of the synthesis report

    • Climate extremes on rise: Due to the current global warming levels, almost every region across the planet is already experiencing climate extremes, an uptick in deaths due to heatwaves, reduced food and water security, and damage to ecosystems, causing mass extinction of species on land and in the ocean.
    • High vulnerability: More than three billion people live in areas that are “highly vulnerable” to climate change.
    • Boost up climate finance: The largest gaps in climate finance are in the developing world, but so too are the largest opportunities.

    Key concerns raised

    The report highlights the urgent need for-

    • Limiting the use of fossil fuels
    • Increasing finance to climate investments
    • Expanding the clean energy infrastructure,
    • Reducing nitrogen pollution from agriculture, curtail food waste, and
    • Adopting measures to make it easier for people to lead low-carbon lifestyles

    Conclusion

    • The report adds that there is still a chance to avert this mass-scale destruction, but it would require an enormous global effort to slash greenhouse gas emissions in half by 2030 and completely phase them out by 2050.
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  • Meeting India’s ‘Carbon Sink’ target

    carbon-sink

    Central idea: India’s commitment to reduce its carbon emissions and increase its carbon sink as part of the Paris Climate Agreement. The Agreement is a legally binding international treaty signed by 196 parties, including India, to limit global warming to well below 2°C.

    What is a carbon sink?

    • A carbon sink is a natural or artificial reservoir that absorbs and stores carbon dioxide (CO2) from the atmosphere.
    • It can be a natural ecosystem such as forests, oceans, or soil, or it can be an artificial system like carbon capture and storage (CCS) technology.
    • Carbon sinks help to reduce the amount of CO2 in the atmosphere and mitigate the negative effects of climate change.

    Methods of Carbon Sinks

    There are two types of carbon sinks:

    (A) Natural Carbon Sinks: These are ecosystems that naturally absorb and store carbon from the atmosphere. The most common natural carbon sinks are:

    • Forests: Trees absorb CO2 through photosynthesis and store it in their trunks, branches, and roots.
    • Oceans: The Ocean absorbs CO2 from the atmosphere, where it dissolves and forms carbonic acid.
    • Soil: Carbon can be stored in soil in the form of organic matter, such as dead plant and animal material, which is broken down by microorganisms.

    (B) Artificial Carbon Sinks: These are human-made technologies that capture and store carbon from the atmosphere. The most common artificial carbon sinks are:

    • Carbon Capture and Storage (CCS): CCS technology captures CO2 emissions from industrial processes, such as power plants, and stores it underground.
    • Direct Air Capture (DAC): DAC technology captures CO2 directly from the air and stores it underground or repurposes it for other uses.

    India’s carbon sink target

    • India has pledged to create an additional carbon sink of 2.5 to 3 billion tonnes of CO2 equivalent by 2030.
    • This will be achieved through afforestation, reforestation, and other land-use changes.

    India’s progress towards its carbon sink target

    • India has already achieved 24.6% of its carbon sink target as of 2017.
    • This was primarily due to afforestation and tree plantation programs, such as the Green India Mission and the National Afforestation Programme.

    Challenges in meeting India’s carbon sink target

    • Unavailability of accurate data: There is a lack of accurate data on the extent and health of India’s forests, which makes it difficult to measure the effectiveness of afforestation and reforestation programs.
    • Conversion of natural forests: The conversion of natural forests to monoculture plantations that have lower carbon sequestration potential can reduce the effectiveness of carbon sinks.
    • Pressure on land: The pressure on land for agriculture and other forms of development can lead to deforestation and the loss of carbon sinks.
    • Lack of funding: Afforestation and reforestation programs require significant funding, which can be a challenge for India.
    • Lack of awareness: Lack of awareness among the public and policymakers about the importance of carbon sinks and the need for their conservation and restoration can hinder efforts to meet India’s carbon sink targets.

    Conclusion

    • India’s commitment to increasing its carbon sink is crucial in mitigating the impacts of climate change.
    • More efforts are needed to ensure the success of afforestation and reforestation programs and to address the challenges facing India’s forests.
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  • UNEP pitches for Global Greenhouse Gas Monitoring Infrastructure

    greenhouse

    Central idea: The article discusses the United Nations’ development of a new system for tracking greenhouse gas emissions.

    Greenhouse Gases

    • Greenhouse gases are gases that trap heat in the Earth’s atmosphere and contribute to the greenhouse effect.
    • Examples of greenhouse gases include-
    1. Water vapor (H2O)
    2. Carbon dioxide (CO2)
    3. Methane (CH4)
    4. Nitrous oxide (N2O)
    5. Fluorinated gases, including hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6)
    6. Ozone (O3)
    • The greenhouse effect is a natural process that occurs when certain gases in the atmosphere absorb and re-emit infrared radiation from the sun, trapping heat and keeping the planet warm enough to sustain life.
    • Human activities such as burning fossil fuels, deforestation, and industrial processes have significantly increased the concentration of greenhouse gases in the atmosphere, leading to an enhanced greenhouse effect and causing global warming and climate change.

    Global Greenhouse Gas Monitoring Infrastructure

    • The new system, also known as the Common Global Standard for Sustainability, is being developed by the United Nations Environment Programme (UNEP).
    • It will provide a standardized framework for measuring and reporting greenhouse gas emissions across various sectors, including agriculture, transport, and energy.

    Need for the new system

    • The current system for tracking greenhouse gas emissions is fragmented and lacks standardization, making it difficult to compare emissions across different sectors and countries.
    • The new system aims to address this issue by providing a standardized framework for measuring and reporting emissions.

    Benefits offered

    • The new system will provide a more accurate and comprehensive picture of greenhouse gas emissions across different sectors and countries.
    • It will enable policymakers and businesses to develop more effective strategies for reducing emissions and mitigating the impacts of climate change.

    Challenges

    • The success of the new system will depend on the willingness of countries and businesses to adopt and implement it.
    • There may be resistance from some countries and businesses that are reluctant to disclose their emissions data or make changes to their current reporting practices.

     

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  • Heat Waves and the anatomy behind

    heat

    The Indian Meteorological Department (IMD) has already started sensing the first signs of heat waves for this summer season.

    What is the news?

    • The IMD warned that the maximum temperatures over northwest, west, and central India would be 3-5° C higher than the long-term average in this week.
    • If the heat waves had played out, they would have been the earliest these regions would have experienced this deadly phenomenon.

    What are Heat Waves?

    • Heatwaves generally occur over India between March and June.
    • IMD declares a heatwave event when the maximum (day) temperature for a location in the plains crosses 40 degrees Celsius.
    • Over the hills, the threshold temperature is 30 degrees Celsius.

    How are they formed?

    • Heatwaves form when high pressure aloft (3,000–7,600 metres) strengthens and remains over a region for several days up to several weeks.
    • This is common in summer (in both Northern and Southern Hemispheres) as the jet stream ‘follows the sun’.
    • On the equator side of the jet stream, in the upper layers of the atmosphere, is the high pressure area.
    • Summertime weather patterns are generally slower to change than in winter. As a result, this upper level high pressure also moves slowly.
    • Under high pressure, the air subsides (sinks) toward the surface, warming and drying adiabatically, inhibiting convection and preventing the formation of clouds.
    • Reduction of clouds increases shortwave radiation reaching the surface.
    • A low pressure at the surface leads to surface wind from lower latitudes that brings warm air, enhancing the warming.
    • Alternatively, the surface winds could blow from the hot continental interior towards the coastal zone, leading to heat waves.

    Following criteria are used to declare heatwave:

    To declare heatwave, the below criteria should be met at least in 2 stations in a Meteorological subdivision for at least two consecutive days and it will be declared on the second day.

    (a) Based on Departure from Normal

    • Heat Wave: Departure from normal is 4.5°C to 6.4°C
    • Severe Heat Wave: Departure from normal is >6.4°C

    (b) Based on Actual Maximum Temperature (for plains only)

    • Heat Wave: When actual maximum temperature ≥ 45°C
    • Severe Heat Wave: When actual maximum temperature ≥47°C

     

    Recent context: El Nino + heat waves

    • The last three years have been La Nina years, which has served as a precursor to 2023 likely being an El Nino
    • The El Nino is a complementary phenomenon in which warmer water spreads west-east across the equatorial Pacific Ocean.
    • As we eagerly await the likely birth of an El Nino this year, we have already had a heat wave occur over northwest India.
    • Heat waves tend to be confined to north and northwest India in El Nino years.

    Why do heat waves occur in the first place?

    • Heat waves are formed for one of two reasons: because warmer air is flowing in from elsewhere or because something is producing it locally.
    • Air is warmed locally when the air is warmed by higher land surface temperature or because the air sinking down from above is compressed along the way, producing hot air near the surface.

    How do different processes contribute to the formation of a heat wave?

    • The direction of air flowing in from the west-northwest, warming in the Middle East, and compression over mountains of Afghanistan and Pakistan cause warm air to enter India.
    • The warming Arabian Sea also contributes to the warming trend.
    • Upper atmospheric westerly winds control near-surface winds, which rotate faster than the planet itself.
    • Additionally, the lapse rate, or the rate at which temperatures cool from surface to upper atmosphere, is declining due to global warming.

    Regional occurrences

    • The other factors that affect the formation of heat waves are the age of the air mass and how far it has traveled.
    • The north-northwestern heatwaves are typically formed with air masses that come from 800-1,600 km away and are around two days old.
    • Heat waves over peninsular India on the other hand arrive from the oceans, which are closer (around 200-400 km) and are barely a day old.
    • As a result, they are on average less intense.