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GS Paper: GS1-14.Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc.,

  • Climate Crisis, India’s Solution – Mission LiFE

    Mission LiFE

    Context

    • Prime Minister Narendra Modi on October 20 unveiled the action plan for Mission LiFE (Lifestyle for Environment), an India-led global mass movement that will nudge individuals and communities for action to protect and preserve the environment.

    What is LiFE?

    • Importance of individual efforts: Mission LiFE makes environmental protection and conservation a participative process and recognizes the importance of each effort no matter how small or big to save the environment both at the level of the individual and at the level of the community.
    • Chaning utilization attitude: The idea promotes an environmentally conscious lifestyle that focuses on ‘mindful and deliberate utilization’ instead of ‘mindless and wasteful consumption’.
    • Creating social networks: The LIFE Movement aims to utilize the power of collective action and nudge individuals across the world to undertake simple climate-friendly actions in their daily lives. The LIFE movement, additionally, also seeks to leverage the strength of social networks to influence social norms surrounding climate.
    • Creating Pro-planet people: The Mission plans to create and nurture a global network of individuals, namely ‘Pro-Planet People’ (P3), who will have a shared commitment to adopt and promote environmentally friendly lifestyles.
    • Seeks to behavioral change and individual actions: Through the P3 community, the Mission seeks to create an ecosystem that will reinforce and enable environmentally friendly behaviors to be self-sustainable. LIFE recognizes that small individual actions can tip the balance in the planet’s favour.

    Do you know pro-planet initiatives worldwide?

    • Denmark:  Denmark promotes the use of bicycles by limiting parking within the city Centre and providing exclusive bike lanes.
    • Japan: Japan has its unique “walk-to-school” mandate, which has been in practice since the early 1950s.

    Mission LiFE

    Why is the need for such movement?

    • Wrong perception about conservation: Environment protection, has for far too long been perceived as a policy issue by the general masses. There has been a perception that only national governments and international organizations can do something to protect the Earth and environment.

    How mission LiFE will be helpful?

    • Mindless consumption of resources: The human race is plundering Planet Earth at a pace that far outstrips its capacity and ability to support life. A recent study says that if the current rate of consumption were to continue, by 2050, humans would need two more planets, in addition to the Earth, to continue to exist.
    • Declining natural resources and beauty: This means that we could be staring at major climatic crises in the years to come and our future generations may never get to experience the beauty of nature, the glaciers, the oceans, the snow and the rivers, that we have been fortunate to see and experience.
    • Unsustainable consumption pattern: What threatens our existence more than anything else is the pace at which we are producing and consuming. The consumption pattern of the world is mindless and pays scant regard to the environment.
    • Attitude change through mission LiFE: Mission LiFE tries to remind the world that the mindset of “use and throw” must immediately be replaced by “reduce, reuse and recycle” so that our scarce resources are not overexploited, and the world doesn’t crumble under the weight of all the waste that it is generating by the second.
    • Small efforts big Impact: Mission LiFE is a philosophy which shows how this can be made possible. It shows the power of small efforts to make big impacts. It believes in the individual’s capacity to change the world. It is the mantra to reverse historical and cultural wrongs wrecked upon the environment. Mission LiFE is the call to action for citizens and governments to save the planet.

    Mission LiFE

    What are India’s efforts for LiFE?

    • Environment friendly culture: In India, the cultural ethos of limiting needs and treating the environment and its resources with reverence has produced very visible results. India constitutes 17 per cent of the world’s population, but our contribution to global carbon emissions is only four per cent.
    • Less carbon footprint per head: Against the developed world’s carbon footprint of four tonnes per head, the carbon footprint of an average Indian counts to only 1.5 tonnes.
    • Multiple global initiatives: Despite not being part of the problem, with numerous global initiatives such as the International Solar Alliance, the One Sun One World One Grid initiative, and the Coalition for Disaster Resilient Infrastructure, India has taken the lead in presenting and building solutions for the world by bringing the global community together.
    • Focus on collective actions of world community: The need to build these global alliances to fight climate change stems from the understanding that only collective action can save the world from the vagaries of climate change that are increasingly becoming a reality and are rising in ferocity.
    • Mindful utilization of resources: India offering knowledge from its religious and cultural ethos to the world, Mission LiFE aims to pull the world away from a “mindless and destructive” consumerist approach towards a “mindful and deliberate utilization” of resources. It is also, at the same time, an effort to prevent India from heading that way.
    • Shift towards sustainable policies: India is already working towards building a circular economy and moving towards a stage where all our energy requirements are met through the use of renewables. Our policies are all aligned towards ensuring sustainable development, where nature is not disregarded for development but where the most marginalized are not left to their destiny by denying them development.

    Mission LiFE

    Conclusion

    • Actions against climate change is not just a fervent hope but an emergent necessity. Through mission LiFE India is trying to portray climate crisis from individual perspective. Mission LiFE has a potential to transform climate change movement into the mass movement.

    Mains Question

    How Mission LiFE will help in conservation of Environment? Critically analyze the India’s efforts to make LiFE a successful mission?

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  • PM launches Mission LiFE

    Prime Minister, in the presence of UN Secretary-General Antonio Guterres, launched ‘Mission LiFE’ (Lifestyle For Environment).

    What is Mission LiFE?

    • NITI Aayog has conceptualized the idea of mission LiFE.
    • It states that the aim of the mission is to follow a three-pronged strategy for changing our collective approach toward sustainability.
    • PM elaborated that Mission LiFE emboldens the spirit of the P3 model i.e. Pro Planet People.
    • The approach of LiFe campaign includes:
    1. Focus on individual behaviours: To make life a mass movement (Jan Andolan).
    2. Co-create globally: Crowdsourcing empirical and scalable ideas
    3. Leverage Local Cultures: Leverage climate-friendly social norms and beliefs of different cultures worldwide to drive the campaign

    Understanding Sustainable living

    • United Nations Environment Programme (UNEP) is the global authority that sets environmental agenda and promotes the implementation of environmental dimension of sustainable development.
    • UNEP says that as the population of the world is increasing the demand for food, fashion, travel, housing, etc also increases.
    • Hence, a sustainable living approach is necessary to make a balance between the needs of the present generation with that of the future.
    • Sustainable living means acknowledging day-to-day life choices and reflecting if there can be alternatives that may impact the environment less.

     

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  • What is International Argo Program?

    argo

    The International Argo Program system to observe carbon concentration in the world’s oceans is extremely inadequate to meet the growing and urgent need for information on oceanic carbon, says a report.

    What is Argo?

    • Argo is an international program that uses profiling floats to observe temperature, salinity, currents, and, recently, bio-optical properties in the Earth’s oceans; it has been operational since the early 2000s.
    • The real-time data it provides is used in climate and oceanographic research.
    • A special research interest is to quantify the ocean heat content (OHC).
    • Each instrument (float) spends almost all its life below the surface.
    • The name Argo was chosen because the array of floats works in partnership with the Jason earth observing satellites that measure the shape of the ocean surface.
    • In Greek mythology Jason sailed on his ship the Argo in search of the Golden Fleece.

    What are its aims?

    • The data that Argo collects describes the temperature and salinity of the water and some of the floats measure other properties that describe the biology/chemistry of the ocean.
    • The main reason for collecting these data is to help us understand the oceans’ role in earth’s climate.
    • For example, the changes in sea level (once the tides are averaged out) depend partly on the melting of icecaps and partly on the amount of heat stored in the oceans.
    • Argo’s temperature measurements allow us to calculate how much heat is stored and to monitor from year to year how the distribution of heat changes with depth and from area to area.
    • As ocean heat content increases, sea level rises, just like the mercury in a thermometer.

    How does it work?

    • Each Argo float (costing between $20,000 and $150,000 depending on the individual float’s technical specification) is launched from a ship.
    • The float’s weight is carefully adjusted so that, as it sinks, it eventually stabilizes at a pre-set level, usually 1 km.
    • Ten days later, an internal battery-driven pump transfers oil between a reservoir inside the float and an external bladder.
    • This makes the float first descend to 2km and then return to the surface measuring ocean properties as it rises.
    • The data and the float position are relayed to satellites and then on to receiving stations on shore.
    • The float then sinks again to repeat the 10 day cycle until its batteries are exhausted.

     

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  • What is a Triple-Dip La Nina?

    nina

    Parts of the world are expected to experience severe weather for the rest of the year and into 2023, as part of a rare “triple dip La Nina” event, according to the World Meteorological Organization (WMO).

     What is the “Triple-Dip” La Nina?

    • A “triple-dip” La Nina is a multiyear cooling of the surface temperature of the equatorial Pacific Ocean, which can cause droughts, fierce winds and heavy rainfall.
    • According to WMO, the current La Nina is projected to span three consecutive northern hemisphere winters. It began in September 2020.
    • If it continues for the next six months, it will be the first “triple-dip” La Nina event of the 21st century, WMO says.

    How rare is this triple-dip?

    • It is exceptional to have three consecutive years with a la Nina event.
    • Its cooling influence is temporarily slowing the rise in global temperatures – but it will not halt or reverse the long-term warming trend.
    • La Nina’s are usually preceded by El Nino, a weather pattern that warms the surface of the eastern tropical Pacific Ocean.
    • However, an El Nino event did not occur before the current La Nina.

    Has it happened before? Will it happen again?

    • La Nina’s occurred several times between 1903 to 2010 and 2010 to 2012.
    • This would be the first “triple-dip” La Nina this century.
    • However, it is not unprecedented for the weather pattern to last more than nine months to a year, which is typical for a La Nina.

    Evaluating the likely impact

    • In the Indian context, La Nina is associated with good rainfall during the monsoon season.
    • This is the opposite of El Nino which is known to suppress monsoon rainfall.
    • Thus, a continued spell of La Nina could lead to expectation of another year of good, or normal, rainfall during the monsoon.
    • Until now, the monsoon season this year has produced 7% more rain compared to normal. Last year, the seasonal rainfall was almost 100%.
    • But, even though powerful, ENSO condition is only one of the several factors affecting monsoon rainfall in India.

    Impact on rainfall

    • There is no one-on-one correlation between the ENSO condition and the amount of rainfall.
    • Also, the influence of ENSO is at a macro level.
    • There are wide variations in rainfall at the local level, which are getting exacerbated by climate change.

    Differential impacts of this triple-dip event

    • The continuance of La Nina further into 2023 is not bad news from the Indian standpoint. But it is not the same for many other regions where La Nina has very different impacts.
    • In most parts of the United States, for example, La Nina is associated with very dry winters.
    • In Australia and Indonesia, and generally in the tropical region, La Nina is expected to bring more rainfall.
    • The excessive rainfall in Pakistan, which is experiencing its worst flooding disaster, can also be blamed in part on La Nina.
    • It said that the persistence of La Nina was most likely to result in a worsening of the drought in Africa.

    What is its climate change link?

    • Every unusual weather event these days is attributed to climate change, but science is not conclusive right now.
    • The occurrences of El Nino or La Nina are not very regular.
    • Sometimes they emerge every two years, at other times there has been a gap of even seven years.
    • Historical records do not go very far in the past.
    • As a result, the natural variability of ENSO is not understood very clearly.
    • And when the natural variability itself is not clear, the influence of global warming is difficult to quantify.
    • But there is clearer evidence of another kind of linkage with global warming.
    • During La Nina years, the colder surfaces allow the oceans to absorb more heat from the atmosphere.
    • Consequently, the air temperatures tend to go down, producing a cooling effect.

     

     

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  • UNEP launches Green Fins Hub

    fins

    The United Nations Environmental Programme (UNEP) has launched the Green Fins Hub, a global digital platform to give sustainable marine tourism a ‘major boost’.

    Green Fins Hub

    • The Green Fins Global Hub will be a first-of-its-kind online support system to motivate scuba operators to improve their daily environmental practices at scale.
    • It aims to help diving and snorkeling operators worldwide to make simple, cost-efficient changes to their daily practices by utilizing tried and tested solutions.
    • It would also help them keep track of their annual improvements and communicate with their communities and customers.

    Membership of Green Fins Hub

    • It will host two types of membership. One would be digital membership available for diving, snorkelling and liveaboard operations globally.
    • Throughout every year of membership, operators will receive environmental scores based on a detailed online self-evaluation and progress made on their action plans.
    • The Certified Members will continue to be assessed annually and trained in person at their operation.
    • The platform will be for operators around the world to raise industry needs, discuss environmental issues and share lessons and ideas with like-minded industry leaders, non-profits and governments.

     

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  • Why Cloudbursts forecast in India still remains elusive?

    cloudbursts

    The characteristics of cloud burst events remain elusive, and our efforts in monitoring and forecasting them is at an embryonic stage.

    Cyclones can be predicted about one week in advance. However, cloudburst forecasts still remain elusive.

    What is Cloudbursts?

    • A cloudburst is a localised but intense rainfall activity.
    • Short spells of very heavy rainfall over a small geographical area can cause widespread destruction, especially in hilly regions where this phenomenon is the most common.
    • Not all instances of very heavy rainfall, however, are cloudbursts.
    • A cloudburst has a very specific definition: Rainfall of 10 cm or more in an hour over a roughly 10 km x 10-km area is classified as a cloudburst event.
    • By this definition, 5 cm of rainfall in a half-hour period over the same area would also be categorized as a cloudburst.

    Which clouds do burst?

    • Cloudburst events are often associated with cumulonimbus clouds that cause thunderstorms and occasionally due to monsoon wind surges and other weather phenomena.
    • Cumulonimbus clouds can grow up to 12-15 km in height through the entire troposphere (occasionally up to 21 km) and can hold huge amounts of water.
    • Tall cumulonimbus clouds can develop in about half an hour as the moisture updraft happens rapidly, at a pace of 60 to 120 km/hr.
    • A single-cell cloud may last for an hour and dump all the rain in the last 20 to 30 minutes, while some of these clouds merge to form multi-cell storms and last for several hours.
    • However, cloudbursts are not defined based on cloud characteristics and do not indicate clouds exploding. Cloudbursts are defined by the amount of rainfall.

    How is it different from normal rainfall?

    • According to the India Meteorological Department (IMD), 100 mm of rain in an hour is called a cloudburst.
    • Usually, cloudbursts occur over a small geographical region of 20 to 30 sq. km.

    When do they occur?

    • In India, cloudbursts often occur during the monsoon season, when the southwesterly monsoon winds bring in copious amounts of moisture inland.
    • The moist air that converges over land gets lifted as they encounter the hills.
    • The moist air reaches an altitude and gets saturated, and the water starts condensing out of the air forming clouds.
    • This is how clouds usually form, but such an orographic lifting together with a strong moisture convergence can lead to intense cumulonimbus clouds taking in huge volumes of moisture that is dumped during cloudbursts.

    How common are cloudbursts?

    • Cloudbursts are not uncommon events, particularly during the monsoon months.
    • Most of these happen in the Himalayan states where the local topology, wind systems, and temperature gradients between the lower and upper atmosphere facilitate the occurrence of such events.
    • However, not every event that is described as a cloudburst is actually, by definition, a cloudburst.
    • That is because these events are highly localized.
    • They take place in very small areas which are often devoid of rainfall measuring instruments.

    Climate change and cloudbursts: How are they related?

    • Climate change is projected to increase the frequency and intensity of cloudbursts worldwide.
    • As the air gets warmer, it can hold more moisture and for a longer time. We call this the Clausius Clapeyron relationship.
    • A 1-degree Celsius rise in temperature may correspond to a 7-10% increase in moisture and rainfall.
    • This increase in rainfall amount does not get spread moderately throughout the season.
    • As the moisture holding capacity of air increases, it results in prolonged dry periods intermittent with short spells of extreme rains.
    • Deeper cumulonimbus clouds will form and the chances of cloudbursts also increase.

    Why are they so destructive?

    • The consequences of these events, however, are not confined to small areas.
    • Because of the nature of terrain, the heavy rainfall events often trigger landslides and flash floods, causing extensive destruction downstream.
    • This is the reason why every sudden downpour that leads to destruction of life and property in the hilly areas gets described as a “cloudburst”, irrespective of whether the amount of rainfall meets the defining criteria.
    • At the same time, it is also possible that actual cloudburst events in remote locations aren’t recorded.

    Detecting cloudbursts

    • Satellites are extensively useful in detecting large-scale monsoon weather systems.
    • However the resolution of the precipitation radars of these satellites can be much smaller than the area of individual cloudburst events, and hence they go undetected.
    • Weather forecast models also face a similar challenge in simulating the clouds at a high resolution.
    • The skillful forecasting of rainfall in hilly regions remains challenging due to the uncertainties in the interaction between the moisture convergence and the hilly terrain.
    • There also involves the cloud microphysics, and the heating-cooling mechanisms at different atmospheric levels.
    • Multiple radars can be a quick measure for providing warnings, but radars are an expensive affair, and installing them across the country may not be practically feasible.

    Solutions to cloudbursts forecast

    • Multiple doppler weather radars can be used to monitor moving cloud droplets and help to provide nowcasts (forecasts for the next three hours).
    • A long-term measure would be mapping the cloudburst-prone regions using automatic rain gauges.
    • If cloudburst-prone regions are co-located with landslide-prone regions, these locations can be designated as hazardous.

     

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  • What is the idea of Climate Reparation?

    Facing the worst flooding disaster in its history, Pakistan has begun demanding reparations, or compensation, from the rich countries that are mainly responsible for causing climate change.

    Why in news?

    • On the face of it, Pakistan’s demand for reparations appears to be a long shot, but the principles being invoked are fairly well-established in environmental jurisprudence.
    • In fact, Pakistan is not alone in making this demand.
    • Almost the entire developing world has for years been insisting on setting up an international mechanism for financial reparation for loss and damage caused by climate disasters.
    • The issue has come up repeatedly at international negotiations for climate change, and on other platforms.

    What is Climate Reparation?

    • At its heart, the demand for compensation for loss and damage from climate disasters is an extension of the universally acknowledged “Polluter Pays” principle.
    • This makes the polluter liable for paying not just for the cost of remedial action, but also for compensating the victims of environmental damage caused by their actions.
    • Climate justice is based on the notion of not being punished for someone else’s bad behaviour, but it does not sanction additional bad behaviour.

    Who are responsible for climate change?

    • In the climate change framework, the burden of responsibility falls on those rich countries that have contributed most of the greenhouse gas emissions since 1850, generally considered to be the beginning of the industrial age.
    • The United States and the European Union, including the UK, account for over 50% of all emissions during this time.
    • If Russia, Canada, Japan, and Australia too are included, the combined contribution goes past 65%, or almost two-thirds of all emissions.
    • Historical responsibility is important because carbon dioxide remains in the atmosphere for hundreds of years, and it is the cumulative accumulation of carbon dioxide that causes global warming.

    What about developing countries?

    • A country like India, currently the third largest emitter, accounts for only 3% of historical emissions.
    • China, which is the world’s biggest emitter for over 15 years now, has contributed about 11% to total emissions since 1850.

    Why need climate reparations?

    • While the impact of climate change is global, it is much more severe on the poorer nations because of their geographical locations and weaker capacity to cope.
    • Countries that have had negligible contributions to historical emissions and have severe limitations of resources are the ones that face the most devastating impacts of climate change.

    Institutional mechanism for Climate Reparations

    (1) United Nations

    • The UN Framework Convention on Climate Change (UNFCCC), the 1994 international agreement that lays down the broad principles of the global effort to fight climate change.
    • It explicitly acknowledges this differentiated responsibility of nations.
    • It makes it very clear that rich countries must provide both the finance and the technology to the developing nations to help them tackle climate change.
    • It is this mandate that later evolved into the $100 billion amount that the rich countries agreed to provide every year to the developing world.
    • While this promise is yet to be met, this $100 billion per year amount is not meant for loss and damage.
    • Climate disasters were not a regular occurrence in 1994, and as such the UNFCCC does not make a mention of loss and damage.
    • This particular demand emerged much later, and faced stiff resistance from the developed nations.

    (2) Warsaw International Mechanism (WIM)

    • The WIM for Loss and Damages, set up in 2013, was the first formal acknowledgment of the need to compensate developing countries struck by climate disasters.
    • However, the progress on this front has been painfully slow.
    • No funding mechanism, or even a promise to provide funds, has come about.

    Pushback from Developed Countries

    • It is not hard to understand why the developed countries are dead against compensation claims.
    • They are struggling to put together even the $100 billion per year flow that they had reluctantly agreed to provide.
    • Further, loss and damage claims can easily spiral into billions of dollars, or even more.
    • The report said that the United States alone is estimated to have “inflicted more than $1.9 trillion in damages to other countries” due to its emissions.

    Issues with loss assessment

    • There are practical difficulties in estimating how much a country has actually suffered due to the actions of others.
    • To begin with, it has to be established that the disaster was caused by climate change.
    • Then there are non-economic losses as well, including loss of lives, displacement and migration, health impacts, and damage to cultural heritage.
    • Then there is this other step about assessing how much of the losses are due to the event itself, and what could be attributed to misgovernance.

    Conclusion

    • A lot of background work is going on to create the framework in which it would be possible to quantify the compensation due to an affected country.
    • What Pakistan has done, through its demands for reparations, is to call attention to this often neglected aspect.

     

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  • Abnormal’ La Nina conditions impacting India’s monsoon

    In what may be termed as an uncommon ocean phenomenon, the prevailing La Nina conditions over the equatorial Pacific Ocean have entered the third consecutive year.

    What is the news?

    • The current La Nina phase has been prevailing since September 2020.
    • Since the 1950s, La Nina lasting for more than two years has been recorded only on six instances (see graph below), data by the India Meteorological Department (IMD) stated.
    • It confirmed that India’s La Nina conditions are here to stay till the end of 2022.

    What is El Nino and La Nina?

    • While El Nino (Spanish for ‘little boy’), the more common expression, is the abnormal surface warming observed along the eastern and central regions of the Pacific Ocean (the region between Peru and Papua New Guinea).
    • The La Nina (Spanish for ‘little girl’) is an abnormal cooling of these surface waters.
    • Together, the El Nino (Warm Phase) and La Nina (Cool Phase) phenomena are termed as El Nino Southern Oscillation (ENSO).
    • These are large-scale ocean phenomena that influence the global weather — winds, temperature and rainfall. They have the ability to trigger extreme weather events like droughts, floods, hot and cold conditions, globally.
    • Each cycle can last anywhere between 9 to 12 months, at times extendable to 18 months — and re-occur after every three to five years.
    • Meteorologists record the sea surface temperatures for four different regions, known as Nino regions, along this equatorial belt.
    • Depending on the temperatures, they forecast either as an El Nino, an ENSO neutral phase, or a La Nina.

    Why has La Nina conditions continued for 3 years?

    • It is surprising that it has continued for the last three years. It may be good for India but not for some other countries.
    • Under climate change conditions, one must expect more such instances. Climate change could be a factor driving such anomalous conditions.

    Issues with La Nina

    • La Nina years are infamous for frequent and intense hurricanes and cyclones in the Atlantic Ocean and the Bay of Bengal.
    • Chances of more cyclones are likely due to multiple aiding factors, including high relative moisture and relative low wind shear over the Bay of Bengal.

     

    Try this PYQ:

    Q. La Nina is suspected to have caused recent floods in Australia. How is La Nina different from El Nino?

    1. La Nina is characterized by unusually cold ocean temperature in equatorial Indian Ocean whereas El Nino is characterized by unusually warm ocean temperature in the equatorial Pacific Ocean.
    2. El Nino has an adverse effect on south-west monsoon of India, but La Nina has no effect on monsoon climate.

    Which of the statements given above is/are correct?

    (a) Only 1

    (b) Only 2

    (c) Both 1 and 2

    (d) Neither 1 nor 2

     

    [wpdiscuz-feedback id=”b6qp23xiv6″ question=”Please leave a feedback on this” opened=”1″]Post your answers here.[/wpdiscuz-feedback]

     

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  • Recovery of Ozone Layer achieves significant milestone

    The concentration of ozone-depleting substances in the atmosphere has reduced to reach a significant milestone this year.

    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.

    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

     

    [wpdiscuz-feedback id=”dl4j162prv” question=”Please leave a feedback on this” opened=”1″]Post your answers here[/wpdiscuz-feedback]

     

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  • What are Cloudbursts? Why are they rising across India?

    Over 20 people have been killed in destruction caused by cloudbursts and flash floods in different parts of Himachal Pradesh and Uttarakhand over the last three days.

    What are Cloudbursts?

    • A cloudburst is a localised but intense rainfall activity.
    • Short spells of very heavy rainfall over a small geographical area can cause widespread destruction, especially in hilly regions where this phenomenon is the most common.
    • Not all instances of very heavy rainfall, however, are cloudbursts.
    • A cloudburst has a very specific definition: Rainfall of 10 cm or more in an hour over a roughly 10 km x 10-km area is classified as a cloudburst event.
    • By this definition, 5 cm of rainfall in a half-hour period over the same area would also be categorized as a cloudburst.

    How is it different from normal rainfall?

    • To put this in perspective, in a normal year, India, as a whole, receives about 116 cm of rainfall over the entire year.
    • This means if the entire rainfall everywhere in India during a year was spread evenly over its area, the total accumulated water would be 116 cm high.
    • There are, of course, huge geographical variations in rainfall within the country, and some areas receive over 10 times more than that amount in a year.
    • But on average, any place in India can be expected to receive about 116 cm of rain in a year.
    • During a cloudburst event, a place receives about 10% of this annual rainfall within an hour.

    How common are cloudbursts?

    • Cloudbursts are not uncommon events, particularly during the monsoon months.
    • Most of these happen in the Himalayan states where the local topology, wind systems, and temperature gradients between the lower and upper atmosphere facilitate the occurrence of such events.
    • However, not every event that is described as a cloudburst is actually, by definition, a cloudburst.
    • That is because these events are highly localized.
    • They take place in very small areas which are often devoid of rainfall measuring instruments.

    Why are they so destructive?

    • The consequences of these events, however, are not confined to small areas.
    • Because of the nature of terrain, the heavy rainfall events often trigger landslides and flash floods, causing extensive destruction downstream.
    • This is the reason why every sudden downpour that leads to destruction of life and property in the hilly areas gets described as a “cloudburst”, irrespective of whether the amount of rainfall meets the defining criteria.
    • At the same time, it is also possible that actual cloudburst events in remote locations aren’t recorded.

    Can cloudbursts be forecasted?

    • The India Meteorological Department forecasts rainfall events well in advance, but it does not predict the quantum of rainfall — in fact, no meteorological agency does.
    • The forecasts can be about light, heavy, or very heavy rainfall, but weather scientists do not have the capability to predict exactly how much rain is likely to fall at any given place.
    • Additionally, the forecasts are for a relatively large geographical area, usually a region, a state, a meteorological sub-division, or at best a district.
    • As they zoom in over smaller areas, the forecasts get more and more uncertain.
    • Theoretically, it is not impossible to forecast rainfall over a very small area as well, but it requires a very dense network of weather instruments and computing capabilities that seem unfeasible with current technologies.
    • As a result, specific cloudburst events cannot be forecast. No forecast ever mentions a possibility of a cloudburst.
    • But there are warnings for heavy to very heavy rainfall events, and these are routinely forecast four to five days in advance.
    • Possibility of extremely heavy rainfall, which could result in cloudburst kind of situations, are forecast six to 12 hours in advance.

    Are cloudburst incidents increasing?

    • There is no long-term trend that suggests that cloudbursts, as defined by the IMD, are rising.
    • What is well established, however, is that incidents of extreme rainfall, as also other extreme weather events, are increasing — not just in India but across the world.
    • While the overall amount of rainfall in India has not changed substantially, an increasing proportion of rainfall is happening in a short span of time.
    • That means that the wet spells are very wet, and are interspersed with prolonged dry spells even in the rainy season.
    • This kind of pattern, attributed to climate change, does suggest that cloudburst events might also be on the rise.

     

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