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Subject: Climate Change

1. Global Warming and Issues
2. All about Pollution

  • Does Tropical Ozone Hole exist?

    A new ozone hole has been detected over the tropics, at latitudes of 30 degrees South to 30 degrees North, a recent study claimed. But some experts are divided over this.

    Do you know?

    The Antarctic ozone hole — one of the deepest, largest gap in the ozone layer in the last 40 years — has closed, according to the World Meteorological Organization (WMO).

    What is Ozone and Ozone Layer?

    • An ozone molecule consists of three oxygen atoms instead of the usual two (the oxygen we breathe, O2, makes up 21% of the atmosphere).
    • It only exists in the atmosphere in trace quantities (less than 0.001%), but its effects are very important.
    • Ozone molecules are created by the interaction of ultra-violet (UV) radiation from the Sun with O2 molecules.
    • Because UV radiation is more intense at higher altitudes where the air is thinner, it is in the stratosphere where most of the ozone is produced, giving rise to what is called the ‘ozone layer’.
    • The ozone layer, containing over 90% of all atmospheric ozone, extends between about 10 and 40km altitude, peaking at about 25km in Stratosphere.

    Why need Ozone Layer?

    • The ozone layer is very important for life on Earth because it has the property of absorbing the most damaging form of UV radiation, UV-B radiation which has a wavelength of between 280 and 315 nanometres.
    • As UV radiation is absorbed by ozone in the stratosphere, it heats up the surrounding air to produce the stratospheric temperature inversion.

    What is Ozone Hole?

    • Each year for the past few decades during the Southern Hemisphere spring, chemical reactions involving chlorine and bromine cause ozone in the southern polar region to be destroyed rapidly and severely.
    • The Dobson Unit (DU) is the unit of measure for total ozone.
    • The chemicals involved ozone depletion are chlorofluorocarbons (CFCs for short), halons, and carbon tetrachloride.
    • They are used for a wide range of applications, including refrigeration, air conditioning, foam packaging, and making aerosol spray cans.
    • The ozone-depleted region is known as the “ozone hole”.

    Tropical Ozone Hole

    • According to the study, the ozone hole is located at altitudes of 10-25 km over the tropics.
    • This hole is about seven times larger than Antarctica, the study suggested.
    • It also appears across all seasons, unlike that of Antarctica, which is visible only in the spring.
    • The hole has become significant since the 1980s. But it was not discovered until this study.

    What caused an ozone hole in the tropics?

    • Studies suggested another mechanism of ozone depletion: Cosmic rays.
    • Chlorofluorocarbon’s (CFC) role in depleting the ozone layer is well-documented.
    • The tropical stratosphere recorded a low temperature of 190-200 Kelvin (K).
    • This can explain why the tropical ozone hole is constantly formed over the seasons.

    Significance of the finding

    • The tropical ozone hole, which makes up 50 percent of Earth’s surface, could cause a global concern due to the risks associated with it.
    • It is likely to cause skin cancer, cataracts and other negative effects on the health and ecosystems in tropical regions.

    Back2Basics: Antarctic Ozone Hole

    • The Antarctic “ozone hole” was discovered by British Antarctic Survey scientists Farman, Gardiner and Shanklin in 1985.
    • It was caused by the chemical reactions on polar stratospheric clouds (PSCs) in the cold Antarctic stratosphere caused a massive.
    • Though localized and seasonal, an increase in the amount of chlorine present in active, ozone-destroying forms.

    Role of PSCs

    • The polar stratospheric clouds in Antarctica are only formed when there are very low temperatures, as low as −80 °C, and early spring conditions.
    • In such conditions, the ice crystals of the cloud provide a suitable surface for the conversion of unreactive chlorine compounds into reactive chlorine compounds, which can deplete ozone easily.

     

    Try this PYQ

    Q.Consider the following statements:

    Chlorofluorocarbons, known as ozone-depleting substances are used:

    1. In the production of plastic foams
    2. In the production of tubeless tyres
    3. In cleaning certain electronic components
    4. As pressurizing agents in aerosol cans

    Which of the statements given above is/are correct?

    (a) 1, 2 and 3 only

    (b) 4 only

    (c) 1, 3 and 4 only

    (d) 1, 2, 3 and 4

     

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  • Bonn meet

    Context

    From June 6-16, representatives from more than 100 countries descended on Bonn to hold preliminary discussions on what could be the final communiqué at the conclusion of COP27, to be held at Sharm-el-Sheikh later this year.

    Key takeaways from the discussion

    • Centred on climate finance: Discussions were centred around climate finance and there was hardly any convergence of issues.
    • No convergence: The developed and developing countries or for that matter, big polluters and small polluters, were speaking from the ends of the spectrum with no meeting ground.
    • Focus on adaptation and mitigation: Much of the discussion was around “loss and damage”, which was being experienced by many of the smaller countries, especially with big coastlines, due to rising river levels, loss of agricultural productivity, loss of livelihoods, etc.
    • The idea to provide assistance for “loss and damage” was opposed by the US and the EU.
    • Need for alternative funding: The Green Climate Fund is considered too cumbersome and the process too lengthy.
    • Hence, the need for an alternate funding route was imperative.
    • It was argued that one needs to look into this issue right now and provide financial assistance to cope with it.
    • This brings into focus the debate between adaptation and mitigation.
    • The demand of the developing countries for a provision of climate finance at a scale much higher than $100 billion a year fell on deaf ears.
    • Incidentally, the figure of $100 billion was arrived at arbitrarily and that too way back in 2009.

    Mitigation Vs Adaptation debate

    • More funding directed toward mitigation: It is generally felt that whatever funding has come for climate change issues has mostly been directed towards mitigation.
    • This is primarily because mitigation projects have a cost-benefit analysis and, therefore, it is easy to lend money because you can get it back through interest payments.
    • Cost-benefit analysis: This is primarily because mitigation projects have a cost-benefit analysis and, therefore, it is easy to lend money because you can get it back through interest payments.
    • Mitigation would mean, for example, setting up solar generation units to avoid carbon footprint.
    • Cost-benefit analysis is difficult for adaptation projects, which would be in the form of grants.

    Actions needed to limit the temperature rise to 1.5 degree Celsius

    • 2.4°C by NDC: The Nationally Determined Contributions (NDCs), as on date, are good enough to limit temperature rise to 2.4 degrees centigrade, provided all the targets are met.
    • 1.8°C with net-zero commitment: In addition, if countries also meet their net-zero commitments by 2050, the temperature rise will still be around 1.8 degrees centigrade.
    • 1.5°C:  To limit the temperature rise to 1.5 degrees centigrade, emissions will have to be cut down by half by 2030.
    • The Alliance of Small Island States (AOSIS) expressed the view that to be more meaningful, the aim should be to reduce emissions by 20 per cent by 2025 itself.
    • The logic is that the next round of NDCs is due only in 2025 and by that time, it would be too late to formulate a plan that is achievable by 2030.

    Issue of using remaining carbon space

    • The use of the remaining carbon space available to limit temperature rise to 1.5 degrees centigrade, a highly contentious issue, was also discussed in Bonn.
    • The US resisted being labelled as a “big emitter” and was not willing to take responsibility for its historical emissions.
    • There is no single estimate of how much carbon space is really available as on date, but broad indications are that at the given emissions rate, it would be roughly 10 years.
    • The raging debate is how to distribute this available space equitably amongst countries, which would mean that someone has to take the burden of stiffer targets.
    • What the US wanted other big emitters like China and India take on greater responsibilities for cutting down emissions.
    • However, the like-minded group of developing countries (LMDCs) — which included China, India, Saudi Arabia and the Arab countries — were opposed to this.

    Conclusion

    If there was any hope that discussions at Bonn would provide an acceptable draft, which could be taken forward during COP27, it was misplaced.

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    Back2Basics: The Paris Agreement

    • The Paris Agreement is a legally binding international treaty on climate change. It was adopted by 196 Parties at COP 21 in Paris, on 12 December 2015 and entered into force on 4 November 2016.
    • Its goal is to limit global warming to well below 2, preferably to 1.5 degrees Celsius, compared to pre-industrial levels.
    • To achieve this long-term temperature goal, countries aim to reach global peaking of greenhouse gas emissions as soon as possible to achieve a climate-neutral world by mid-century.
    • It is a landmark process because, for the first time, a binding agreement brings all nations into a common cause to undertake ambitious efforts to combat climate change and adapt to its effects.
    • Implementation of the Paris Agreement requires economic and social transformation, based on the best available science.
    • The Agreement works on a 5- year cycle of increasingly ambitious climate action carried out by countries.
    • By 2020, countries submit their plans for climate action known as nationally determined contributions (NDCs).

    NDCs

    • In their NDCs, countries communicate actions they will take to reduce their Greenhouse Gas emissions in order to reach the goals of the Paris Agreement.
    • Countries also communicate in the NDCs actions they will take to build resilience to adapt to the impacts of rising temperatures.

  • What are Cloudbursts?

    At least eight people have died after a cloudburst occurred at the Amarnath Cave Shrine near Pahalgam in south Kashmir.

    What is a Cloudburst?

    • Cloudbursts are short-duration, intense rainfall events over a small area.
    • According to the IMD, it is a weather phenomenon with unexpected precipitation exceeding 100mm/h over a geographical region of approximately 20-30 square km.

    What causes Cloudburst?

    • A study published last year studied the meteorological factors behind the cloudburst over the Kedarnath region.
    • They analysed atmospheric pressure, temperature, rainfall, cloud water content, cloud fraction, cloud particle radius, cloud mixing ratio, total cloud cover, wind speed, wind direction, and relative humidity during the cloudburst, before as well as after the cloudburst.
    • The results showed that during the cloudburst, the relative humidity and cloud cover was at the maximum level with low temperature and slow winds.
    • It is expected that because of this situation a high amount of clouds may get condensed at a very rapid rate and result in a cloudburst.

    Impact of climate change

    • Several studies have shown that climate change will increase the frequency and intensity of cloudbursts in many cities across the globe.
    • As temperatures increase the atmosphere can hold more and more moisture and this moisture comes down as a short very intense rainfall for a short duration.
    • This results in flash floods in the mountainous areas and urban floods in the cities.
    • Also, there is evidence suggesting that globally short-duration rainfall extremes are going to become more intense and frequent.

    Try this PYQ

    Q.During a thunderstorm, the thunder in the skies is produced by the:

    1. meeting of cumulonimbus clouds in the sky
    2. lightning that separates the nimbus clouds
    3. violent upward movement of air and water particles

    Select the correct option using the codes given below:

    (a) 1 only

    (b) 2 and 3 only

    (c) 1 and 3 only

    (d) None of the above

     

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  • What is the EU’s Sustainable Finance Taxonomy?

    Activists have been widely criticizing the EU’s sustainable finance taxonomy as a “greenwashing” exercise that puts the European Union’s climate change targets at risk.

    What is the EU Taxonomy?

    • The EU taxonomy is a complex system to classify which parts of the economy may be marketed as sustainable investments.
    • It includes economic activities, as well as detailed environmental criteria that each economic activity must meet to earn a green label.

    Why in news now?

    • Rules for most sectors came into effect this year, covering investments including steel plants, electric cars and building renovations.
    • The rules for gas and nuclear energy, however, have been long delayed amid intense lobbying from governments who disagree on whether the fuels help fight climate change.

    What does it say about gas and nuclear energy?

    • The European Parliament supported that proposal in a vote paving the way for it to become law and apply from 2023.
    • Under the proposal, for a gas-fuelled power plant to be deemed green, it must emit no more than 270 grams of CO2 equivalent per kilowatt hour, or have average emissions of 550g CO2e/kW over 20 years.
    • It must also commit to switch to low-carbon gases by 2035.
    • Gas and nuclear power plants are classed as transitional activities.

    What’s the taxonomy for?

    • The taxonomy does not ban investments in activities not labelled “green”, but it limits which ones companies and investors can claim are climate-friendly.
    • The EU’s goal to eliminate its net emissions by 2050 will require huge investments, much of it private funding.
    • The rules also aim to stamp out green-washing, where organisations exaggerate their environmental credentials, among so-called eco-friendly investment products.

    Who does it apply to?

    • Providers of financial products – including pension providers – in the EU must disclose which investments comply with the taxonomy’s climate criteria.
    • For each investment, fund or portfolio, they must disclose what share of underlying investments comply with the rules.
    • Large companies and listed firms must also disclose what share of their turnover and capital expenditure complies.
    • That means polluting companies can get recognition for making green investments.
    • For example, if an oil company invested in a wind farm, it could label that expenditure as green.

    What makes a “green” investment?

    The rules classify three types of green investments.

    • First, those that substantially contribute to green goals, for example, wind power farms.
    • Second, those that enable other green activities, for example, facilities that can store renewable electricity or hydrogen.
    • Third, transitional activities that cannot be made fully sustainable, but which have emissions below industry average and do not lock in polluting assets or crowd out greener alternatives.

     

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  • Commonwealth adopts ‘Living Lands Charter’

    All 54 Commonwealth members have agreed to voluntarily dedicate a ‘living land’ in their respective countries to future generations, in line with the strategy set for the UN Decade on Ecosystem Restoration.

    Living Lands Charter

    • The non-binding mandates that member countries will safeguard global land resources and arrest land degradation while acting against climate change, biodiversity loss and sustainable management.
    • It helps to encapsulate the combined effort to hold the global average temperature increase to 1.5 degrees Celsius, said Commonwealth Secretary-General Patricia Scotland.
    • The document came after nearly two years of intense consultation, engagement and negotiation with member countries at UN Rio Convention.

    Key objectives

    • Leaders and their representatives noted with concern in the charter the alarming decline in the health and productivity of global land resources.
    • It aimed to support member countries to effectively deliver their commitments under the three Rio conventions:
    1. UN Convention on Biological Diversity
    2. UN Convention to Combat Desertification (UNCCD)
    3. UN Framework Convention on Climate Change

    Major outcomes

    • The attendees also underlined the principle of “critical guardianship” provided by indigenous peoples and local communities in protecting land and vital ecosystem services.
    • The agreement was released along with a final wide-ranging communiqué by leaders, including on specific items on climate change.
    • Country heads underscored in it that the “urgent threat of climate change” exacerbates existing vulnerabilities and presents a significant threat to COVID-19 recovery efforts.

     

    Try this PYQ from CSP 2012:

    Q.Consider the following statements:

    1. The Commonwealth has no charter, treaty or constitution
    2. All the territories/countries once under the British Empire (jurisdiction/rule/mandate) automatically joined the Commonwealth as its members

    Which of the statements given above is/are correct?

    (a) 1 only

    (b) 2 only

    (c) Both 1 and 2

    (d) Neither 1 nor 2

     

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    Back2Basics: Commonwealth of Nations

    • The Commonwealth of Nations is an intergovernmental organisation of 53 member states that are mostly former territories of the British Empire.
    • It dates back to the first half of the 20th century with the decolonization of the British Empire through increased self-governance of its territories.
    • It was originally created as the British Commonwealth of Nation through the Balfour Declaration at the 1926 Imperial Conference, and formalized by the UK through the Statute of Westminster in 1931.
    • The current body was formally constituted by the London Declaration in 1949, which modernized the community, and established the member states as “free and equal”.
    • The symbol of this free association is Queen Elizabeth II, who is the Head of the Commonwealth.
    • The Queen is head of state of 16 member states, known as the Commonwealth realms, while 32 other members are republics and five others have different monarchs.
    • Member has no legal obligations to one another. Instead, they are united by language, history, culture and their shared values of democracy, human rights and the rule of law.

     

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  • Odisha’s Mo Bus: Recipient of the UN’s prestigious public service award

    Mo Bus, the bus service of Odisha’s Capital Region Urban Transport (CRUT) authority, has been recognized by the United Nations as one of 10 global recipients of its annual Public Service Awards for 2022.

    Mo Bus service

    • The Mo Bus service was launched on November 6, 2018.
    • It aimed to ensure transformation of the urban public transport scenario in the city and its hinterland through use of smart technology, service benchmarking and customer satisfaction.
    • The buses are designed to integrate smart technologies such as free on-board Wi-Fi service, digital announcements, surveillance cameras, and electronic ticketing.
    • CRUT says that to increase women’s participation in the workforce, and to make women riders feel safer, it is committed to ensuring that 50% of Mo Bus Guides (conductors) are women.

    What is the recent award?

    • The public transport service has been recognised for its role in “promoting gender-responsive public services to achieve the SDGs (Sustainable Development Goals)”.
    • The “impact” is that 57 per cent of the city’s commuters now use the Mo Bus, the UN said.
    • Mo E-Ride is estimated to reduce pollution by 30-50 per cent.

    About UN Public Service Award

    • The UN describes its Public Service Awards as the “most prestigious international recognition of excellence in public service”.
    • The first Awards ceremony was held in 2003, and the UN has since received “an increasing number of submissions from all around the world”.
    • It is intended to reward the creative achievements and contributions of public service institutions that lead to a more effective and responsive public administration in countries worldwide.
    • Through an annual competition, the UN Public Service Awards promotes the role, professionalism and visibility of public service.

     

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  • How Marine Heatwave fuelled super cyclone Amphan

    The super-cyclone Amphan is said to have been triggered by Marine Heatwaves.

    What is the news?

    • A study has found the presence of a strong MHW beneath the track of the cyclone with an extremely high anomalous sea surface temperature of more than 2.5°C.
    • This coincided with the cyclone track and facilitated its rapid intensification in a short period.

    What are Marine Heatwaves?

    • We know that heatwaves occur in the atmosphere. We are all familiar with these extended periods of excessively hot weather.
    • However, heatwaves can also occur in the ocean and these are known as marine heatwaves, or MHWs.
    • These marine heatwaves, when ocean temperatures are extremely warm for an extended period of time can have significant impacts on marine ecosystems and industries.

    When do they occur?

    • Heatwaves can happen in summer and also in winter, where they are known as “winter warm-spells”.
    • These winter events can have important impacts, such as in the southeast of Australia where the spiny sea urchin can only colonize further south when winter temperatures are above 12 °C.

    What causes marine heatwaves?

    • Marine heatwaves can be caused by a whole range of factors, and not all factors are important for each event.
    • The most common drivers of marine heatwaves include ocean currents which can build up areas of warm water and air-sea heat flux, or warming through the ocean surface from the atmosphere.
    • Winds can enhance or suppress the warming in a marine heatwave, and climate modes like El Niño can change the likelihood of events occurring in certain regions.
    • MHWs can be caused due to large-scale drivers of the Earth’s climate like the El Niño Southern Oscillation (ENSO).

    Impacts of the MHWs

    • Marine heatwaves affect ecosystem structure, by supporting certain species and suppressing others.
    • For example, after the 2011 marine heatwave in Western Australia, the fish communities had a much more “tropical” nature than previously and switched from kelp forests to seaweed turfs.
    • Marine heatwaves can cause economic losses through impacts on fisheries and aquaculture.
    • Temperature-sensitive species such as corals are especially vulnerable to MHWs. In 2016, marine heatwaves across northern Australia led to severe bleaching of the Great Barrier Reef.

    How do we measure marine heatwaves?

    • A marine heatwave occurs when seawater temperatures exceed a seasonally-varying threshold (usually the 90th percentile) for at least 5 consecutive days.
    • Successive heatwaves with gaps of 2 days or less are considered part of the same event.

    Why study MHWs?

    • MHWs are increasing in frequency due to climate change. MHWs increased by 54 per cent in the last 30 years.
    • MHW has severe socio-economic consequences such as fish mortality, and coral bleaching, and also has the potential to interact and modify other extreme events such as tropical cyclones.

    Way Forward

    • Marine heatwaves clearly have the potential to devastate marine ecosystems and cause economic losses in fisheries, aquaculture, and ecotourism industries.
    • However, their effects are often hidden from view under the waves until it is too late.
    • By raising general awareness of these phenomena, and by improving our scientific understanding of their physical properties and ecological impacts, we can better predict future conditions and protect vulnerable marine habitats and resources.

     

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  • Issues with the Environmental Performance Index (EPI)

    Context

    The 2022 Environmental Performance Index (EPI) produced by Yale and Columbia Universities and released on World Environment Day (June 5) has triggered much consternation in India, as the country is ranked last (180th).

    Issues with EPI 2022

    • Ignoring the past effects: Indicators may focus on current rates of increase or decrease in environmental pressures (flows) — as the EPI does for carbon dioxide emissions and tree cover gains — but under-state the accumulated effect (stocks) that relates to actual harm, thereby ignoring past effects.
    • Same standard in different socio-ecological context: When ranking countries, one is essentially applying the same standard across vastly different socio-ecological contexts – this involves difficult choices.
    • For example, the EPI leaves out arsenic in water, which is a major threat in Bangladesh.
    • Difficulty in measurement of frogress on climate change: Climate change is a global environmental problem, and because its effects depend on the accumulation of greenhouse gases over time, measuring progress in a given country is challenging.
    • Climate change mitigation has to be measured against what it is reasonable and fair to expect from different countries, taking into account their past emissions as well as national contexts.
    • There has been an inconclusive 30-year debate on this question; any choice of benchmark involves major ethical choices.
    • EPI has given 38 per cent weight to the climate change in the index.
    • They assume that the world must reach net zero emissions by 2050, and so the appropriate benchmark is whether all countries are reducing emissions and reaching zero by 2050.
    • Against CBDR: This approach is contrary to widely accepted ethical principles, especially the global political agreement on common-but-differentiated-responsibility (CBDR).
    • The Yale-Columbia approach ignores the fact that countries have different responsibilities for past accumulations and are at different levels of emissions and energy use.
    • The inclusion of indicators on emissions intensity and emissions per capita partly addresses this issue, but these two account for 7 per cent of the weight, versus 89 per cent for indicators derived from current emission trends.

    Implications EPI’s approach

    • This approach is guaranteed to make richer countries look good, because they have accumulated emissions in the past, but these have started declining in the last decade.
    •  Meanwhile, poorer countries that have emitted comparatively little in the past, look bad.
    • The EPI’s flawed and biased approach distracts from a much-needed honest conversation about the environment in India.
    • India’s local environmental performance on air, water and forests is deeply problematic.
    • Air quality in India is now the second largest risk factor for public health in India, behind only child and maternal nutrition.
    • Rivers and lakes are increasingly polluted, rivers are drying, groundwater tables are rapidly declining, and gains in tree cover hide declining natural productivity and diversity of forests and grasslands.

    Conclusion

    While indices like these have a limited attention-grabbing purpose, they serve this purpose well only when they are focused, limited to easy-to-measure metrics, and consciously minimise value judgements. The EPI 2022 resoundingly fails this test.

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  • Environmental Performance Index (EPI), 2022

    India has objected to a report, called the EPI, 2022, that places the country last (along with Nigeria) on a list of 180 countries on managing climate change, environmental health, and ecosystem vitality.

    Environmental Performance Index

    • The report is prepared by researchers at the Yale and Columbia universities.
    • It provides a data-driven summary of the state of sustainability around the world.
    • Using 40 performance indicators across 11 issue categories, the EPI ranks 180 countries on climate change performance, environmental health, and ecosystem vitality.
    • These indicators provide a gauge at a national scale of how close countries are to established environmental policy targets.
    • The EPI offers a scorecard that highlights leaders and laggards in environmental performance and provides practical guidance for countries that aspire to move toward a sustainable future.

    Why the report is inherently biased?

    • The US placed itself at the 20th spot of the 22 wealthy democracies in the global west and 43rd overall.
    • The relatively low ranking has put all blame on the rollback policies during the Trump administration.
    • It goes on to preach that developing countries do not have to sacrifice sustainability for economic security.

  • Monsoon sets in over Kerala

    The monsoon has reached Kerala, the India Meteorological Department (IMD).

    What does the “Onset of Monsoon” mean?

    • The onset of the monsoon over Kerala marks the beginning of the four-month — June-September — southwest monsoon season over India.
    • It brings more than 70 per cent of the country’s annual rainfall. This marks a significant day in India’s economic calendar.
    • IMD announces it only after certain newly defined and measurable parameters, adopted in 2016, are met.
    • Broadly, the IMD checks for the consistency of rainfall over a defined geography, its intensity, and wind speed.

    (1) Rainfall

    • The IMD declares the onset of the monsoon if at least 60% of 14 designated meteorological stations in Kerala and Lakshadweep.
    • The 14 enlisted stations are: Minicoy, Amini, Thiruvananthapuram, Punalur, Kollam, Alappuzha, Kottayam, Kochi, Thrissur, Kozhikode, Thalassery, Kannur, Kasaragod, and Mangaluru.
    • It records at least 2.5 mm of rain for two consecutive days at any time after May 10.
    • In such a situation, the onset over Kerala is declared on the second day, provided specific wind and temperature criteria are also fulfilled.

    (2) Wind field

    • The depth of westerlies should be up to 600 hectopascal (1 hPa is equal to 1 millibar of pressure) in the area bound by the equator to 10ºN latitude, and from longitude 55ºE to 80ºE.
    • The zonal wind speed over the area bound by 5-10ºN latitude and 70-80ºE longitude should be of the order of 15-20 knots (28-37 kph) at 925 hPa.

    (3) Heat

    • According to IMD, the INSAT-derived Outgoing Longwave Radiation (OLR) value (a measure of the energy emitted to space by the Earth’s surface, oceans, and atmosphere) should be below 200 watt per sq m (wm2).
    • This is measured in the box confined by 5-10ºN latitude and 70-75ºE latitude.

    Is it unusual for the monsoon to hit the Kerala coast early?

    • Neither early nor late onset of the monsoon is unusual.
    • In 2018 and 2017, the onset over Kerala occurred on May 29 and May 30, respectively.
    • In 2010, onset was realised on May 31.
    • In 2020 and 2013, the monsoon was exactly on time, hitting the Kerala coast on June 1.

    Does an early onset foretell a good monsoon?

    • No, it does not — just as a delay does not foretell a poor monsoon.
    • The onset is just an event that happens during the progress of the monsoon over the Indian subcontinent.
    • A delay of a few days, or perhaps the monsoon arriving a few days early, has no bearing on the quality or amount of rainfall.

    How does the monsoon spread across the country after hitting Kerala coast?

    • The northward progression of the monsoon after it has hit the Kerala coast depends on a lot of local factors, including the creation of low pressure areas.
    • Though this year monsoon has arrived early, it is possible that despite a late onset over Kerala, other parts of the country start getting rain on time.
    • After its onset over Kerala, the monsoon spreads over the entire country by July 15.

    Back2Basics:

    Various terms related to Indian Monsoon

     

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