2. About the Total Fertility Rate (TFR)

The Total Fertility Rate (TFR) is a key demographic indicator that helps us understand the average number of children a woman in a specific population will have during her lifetime, assuming current birth patterns persist. It's different from the crude birth rate, which simply measures the number of births per 1,000 people in a population in a given year. 

What it measures

• The average number of children a woman will have throughout her reproductive lifespan.
• It considers age-specific fertility rates, which means it takes into account the different birth rates at different ages within the population.
• Provides a longer-term perspective on population dynamics compared to the crude birth rate.

Significance

• Helps assess population growth trends and predict future population size.
• Informs policy decisions related to education, healthcare, social security, and economic development.
• Understanding TFR is crucial for analyzing the potential demographic dividend, which refers to the economic and social benefits that can arise from a large working-age population due to declining fertility rates.

Calculation

• Summing the age-specific fertility rates (ASFRs) for all fertile age groups (typically 15-49 years) and multiplying by five.
• ASFRs represent the average number of births per 1,000 women in a specific age group.

Key TFR levels

• Replacement fertility rate: Around 2.1 children per woman, ensures population stability without growth or decline due to births and deaths (excluding migration).
• TFR below replacement: Indicates a declining population, with potential implications for workforce size and economic growth.
• TFR above replacement: Leads to population growth, requiring investments in infrastructure and resources to support the growing population.

3. What does the Total Fertility Rate (TFR) of 2.0 mean?

A Total Fertility Rate (TFR) of 2.0 means that, on average, each woman in the population is expected to give birth to two children over her reproductive lifetime. This value represents the replacement level of fertility, where each generation replaces itself in the population. When the TFR is around 2.0, it indicates that the population is stable, with births balancing deaths over time.

A Total Fertility Rate (TFR) of 2.0 indicates several key things

• Average Children per Woman: In that specific population, on average, a woman will have two children during her lifetime, assuming current birth patterns remain unchanged. This means that each generation of women is replacing itself, without population growth or decline due solely to births and deaths (excluding migration).
• Replacement Fertility Rate: A TFR of 2.0 is often referred to as the replacement fertility rate. This is because it signifies the level of fertility needed to maintain a stable population size over time, considering only births and deaths. However, it's important to note that the exact replacement level can vary slightly depending on mortality rates, particularly child mortality.
• Demographic Transition: A TFR of 2.0 suggests that the population is likely in the later stages of the demographic transition. This transition involves a shift from high birth and death rates to low birth and death rates. In this stage, populations typically experience a decline in fertility, followed by a decline in mortality, leading to a stabilization of population size.
• Global Context: While 2.0 is the replacement fertility rate, the global average TFR is currently around 2.3, indicating slight population growth. However, many developed countries have TFRs below replacement level, which can lead to an ageing population and potential challenges for social security systems and workforce size.
• Policy Implications: Understanding the TFR is crucial for policymakers in various areas like education, healthcare, social security, and economic development. A TFR below replacement may necessitate policies encouraging childbirth or attracting immigration to address potential workforce shortages. Conversely, a high TFR might require investments in infrastructure and resources to support a growing population.

4. What is the Replacement Fertility Rate?

The Replacement Fertility Rate (RFR) is the level of fertility required to maintain a stable population size in a given area, considering only births and deaths (excluding migration). This means that each generation of women has just enough daughters to replace themselves and their mothers in the population.

Key Points about RFR

• Typically around 2.1 children per woman This number varies slightly depending on a country's mortality rates, especially child mortality rates. Higher child mortality necessitates slightly higher fertility to ensure replacement.
• When the TFR matches the RFR, the population neither grows nor declines due to births and deaths.
• Reaching RFR suggests a population in the later stages of the demographic transition, characterized by declining birth and death rates.
• Though the global average TFR is 2.3 (slightly above RFR), many developed countries have TFRs below RFR, leading to ageing populations.

Significance of RFR

• Understanding RFR helps policymakers formulate effective policies in areas like education, healthcare, social security, and economic development.
• TFR below RFR may require policies to encourage childbirth or attract immigration to address potential workforce shortages and support ageing populations. Conversely, a high TFR might necessitate investments in infrastructure and resources to sustain a growing population.
• Analyzing TFR about RFR offers insights into potential population growth or decline, aiding in planning and resource allocation.

5. How is the Total Fertility Rate calculated?

The Total Fertility Rate (TFR) is calculated by considering the age-specific fertility rates (ASFRs) of a population. 

1. Age-specific fertility Rates (ASFRs) represent the average number of births per 1,000 women within a specific age group. Typically, ASFRs are calculated for five-year age groups ranging from 15-49 years, covering the typical childbearing years for women. Data for calculating ASFRs usually comes from population censuses or demographic surveys.
2. Once you have the ASFRs for each age group, you need to sum them all up. This gives you the total number of births expected per 1,000 women across all fertile age groups.
3. Since age groups may have different sizes, simply summing ASFRs wouldn't be entirely accurate. To account for this, the sum is multiplied by the average number of women in each age group. This ensures the TFR reflects the fertility rates across all age groups proportionally.
4. Often, instead of using the actual number of women in each age group, a standard factor of "5" is used for convenience. This assumes that each age group has roughly the same number of women, which is a reasonable approximation for many populations.

Therefore, the TFR formula becomes: TFR = (Sum of ASFRs across all age groups) * 5

Example:

Imagine a hypothetical population with the following ASFRs:

• 15-19 years: 30 births per 1,000 women
• 20-24 years: 80 births per 1,000 women
• 25-29 years: 120 births per 1,000 women
• 30-34 years: 90 births per 1,000 women
• 35-39 years: 50 births per 1,000 women
• 40-44 years: 20 births per 1,000 women
• 45-49 years: 10 births per 1,000 women

Using the formula:

• TFR = (30 + 80 + 120 + 90 + 50 + 20 + 10) * 5
• TFR = 400 * 5
• TFR = 2000 births per 1,000 women

Therefore, in this example, the TFR is 2.0, indicating that on average, a woman in this population would have 2 children during her lifetime based on the current age-specific fertility rates.

6. The difference between birth rate and Total Fertility Rate (TFR)

While both birth rate and Total Fertility Rate (TFR) measure fertility within a population, they have key differences that offer distinct insights:

7. About demographic dividend

A demographic dividend refers to the potential economic and social benefits that can arise when a large share of the population is in the working-age (typically 15-64 years) compared to the dependent populations (children and elderly). This shift in population structure is often caused by a decline in fertility rates without a corresponding decline in mortality rates, leading to a "bulge" in the working-age population.

Key Features

• A larger working-age population translates to a larger pool of available labour, potentially boosting economic growth and productivity.
• The ratio of dependents (children and elderly) to the working-age population decreases, leading to increased savings and investment as fewer resources are needed to support dependents.
• The potential for increased investments in education and healthcare due to a smaller dependent population, leading to a more skilled and healthy workforce.

Conditions for a Dividend

• A significant and sustained decline in fertility rates is crucial for the demographic dividend to occur.
• The benefits of a demographic dividend can only be realized if the working-age population is adequately educated, skilled, and healthy.
• Expanding job opportunities is essential to absorb the growing workforce and prevent unemployment.

Challenges and Considerations

• The demographic dividend may not be evenly distributed across regions or social groups, potentially leading to inequalities.
• Governments and businesses need to adapt policies and infrastructure to accommodate the changing population structure.
• Ensuring social security and healthcare for the ageing population is crucial to sustain the benefits of the dividend.

Examples

• Several East Asian countries, like China and South Korea, experienced significant economic growth due to their demographic dividends in the latter half of the 20th century.
• India is currently experiencing a demographic transition with a declining fertility rate, creating the potential for a future dividend. However, realizing this potential requires investments in education, healthcare, and job creation.

 

 

BRAHMOS MISSILE

 

 

1. Context

 

The development of a new, compact air launched version of the BrahMos supersonic cruise missile, the BrahMos-NG (Next Generation), is at an advanced stage, while the range extension of the original BrahMos, much heavier than the air launched one, to 800 km is progressing well, defence sources said.

 

2. What are the BrahMos Missile?

 

• The BrahMos missile is a supersonic cruise missile jointly developed by India's Defence Research and Development Organisation (DRDO) and Russia's NPO Mashinostroyeniya. Its name is a portmanteau of the Brahmaputra and Moskva rivers.
• BrahMos is known for its speed and versatility. It is the fastest cruise missile in the world, capable of reaching speeds of up to Mach 3 (three times the speed of sound). This makes it extremely difficult for enemy defenses to intercept.
• The missile has both land-attack and anti-ship capabilities, meaning it can target both land-based targets and naval vessels. Its precision and range make it a potent weapon for both offensive and defensive purposes. It's deployed across various platforms including land, sea, and air.
• The BrahMos missile has become a significant asset in the Indian military's arsenal, providing a formidable deterrent and offensive capability. It's continuously being upgraded to enhance its capabilities and adapt it to different platforms and operational requirements

3. Evolution of Brahmos

• During the early 1980s, Dr. A P J Abdul Kalam spearheaded the Integrated Guided Missile Development Programme, initiating the creation of various indigenous missiles such as Prithvi, Agni, Trishul, Akash, and Nag, each with diverse capabilities and operational ranges.
• In the early 1990s, India's strategic leadership recognized the necessity for cruise missiles—guided projectiles maintaining nearly constant speeds throughout their trajectories—to deliver sizable warheads with pinpoint accuracy over extensive distances.
• This requirement emerged prominently following the deployment of cruise missiles during the 1991 Gulf War.
• In 1998, an Inter-Governmental Agreement was formalized in Moscow between Dr. Kalam, then heading the DRDO, and N V Mikhailov, Russia's Deputy Defence Minister at the time.
• This agreement laid the foundation for BrahMos Aerospace, a collaborative venture between DRDO and the Russian space company NPO Mashinostroyenia (NPOM), with the Indian side holding 50.5% ownership and the Russians 49.5%. The venture derived its name from two rivers—Brahmaputra in India and Moskva in Russia.
• Subsequently, in 1999, the development of missiles commenced within the laboratories of DRDO and NPOM after BrahMos Aerospace secured funding from both governments. The first successful test launch occurred in 2001 from a specifically engineered land-based launcher

4.Significance of Brahmos

 

• The BrahMos missile is equipped with a solid propellant booster engine, comprising two stages. Initially, the first stage accelerates the missile to supersonic speeds, after which it detaches. Subsequently, the liquid ramjet, constituting the second stage, propels the missile to nearly three times the speed of sound during its cruise phase.
• Notably, the missile exhibits a minimal radar signature, enhancing its stealth capabilities, and can follow various trajectories.
• As a "fire and forget" weapon, it can maintain a cruising altitude of 15 km and descend to as low as 10 meters to effectively strike its target.
• Classified as "standoff range weapons," cruise missiles like BrahMos are launched from a distance substantial enough to evade defensive countermeasures, a feature common among the arsenals of major militaries worldwide.
• Compared to subsonic cruise missiles, BrahMos boasts three times the speed, 2.5 times the flight range, and extended operational capabilities. With export versions available, BrahMos serves as a crucial asset in defense diplomacy initiatives.
• In 2022, an air-launched variant of BrahMos underwent testing from a frontline SU-30MKI aircraft, while an advanced sea-to-sea variant was also tested from the INS Visakhapatnam during the same year.
• However, BrahMos was embroiled in controversy in 2022 when Pakistan alleged that an unarmed Indian missile had inadvertently landed within its territory on March 9, 2022. The Ministry of Defence attributed the incident to a technical malfunction resulting in accidental firing.
• Though the government initiated a high-level inquiry, the specific missile involved was not officially disclosed. Nonetheless, experts inferred from its trajectory that it bore the hallmarks of BrahMos

5. Types of  BrahMos

• The BrahMos missile system is strategically deployed across various fronts, encompassing land-based formations along border regions, BrahMos-equipped Sukhoi-30 aircraft stationed in both the Northern and Southern theaters, and ships and submarines fitted with BrahMos capabilities in naval operations. This integrated setup constitutes a formidable triad, adept at addressing evolving demands in multidimensional warfare scenarios.
• To adapt to dynamic warfare requirements, ongoing efforts are focused on upgrading the BrahMos system, with emphasis on enhancing range, maneuverability, and accuracy.
• Current development initiatives include testing versions with extended ranges of up to 350 km, surpassing the original's 290 km limit. Furthermore, plans are underway for versions with even greater ranges, potentially reaching up to 800 km, and featuring hypersonic speeds. Concurrently, endeavors are directed towards reducing the size and radar signature of existing iterations while augmenting their overall capabilities.
• Across all three branches of the Armed Forces, BrahMos variants are subject to regular testing, including those presently in development.
• Land-Based: The land-based BrahMos setup comprises mobile autonomous launchers, typically housing four to six launchers, each armed with three missiles capable of near-simultaneous firing.
• These batteries are strategically deployed along India's land borders in various theaters. Upgraded versions of the land attack variant, capable of cruising at 2.8 Mach, boast precision striking capabilities with ranges of up to 400 km.
• Advanced iterations with enhanced range and speeds of up to 5 Mach are reportedly in the developmental pipeline. Notably, the ground systems of BrahMos are lauded for their streamlined design and minimal componentry.
• Ship-Based: Since 2005, the Navy has been inducting BrahMos missiles on its frontline warships, enhancing their ability to engage sea-based targets beyond the radar horizon. The naval variant has demonstrated efficacy in both sea-to-sea and sea-to-land engagements.
• These missiles can be deployed individually or in salvos of up to eight, with staggered firing intervals. This capability enables them to effectively target groups of frigates equipped with modern missile defense systems.
• Air-Launched: The successful flight testing of BrahMos from a Sukhoi-30MKI against a sea-based target in the Bay of Bengal on November 22, 2017, marked a significant milestone. Subsequent tests have validated its effectiveness.
• The BrahMos-equipped Sukhoi-30 aircraft, boasting a range of 1,500 km without mid-air refueling, serve as a pivotal strategic deterrent along both land borders and the strategically vital Indian Ocean Region. The Indian Air Force is actively integrating BrahMos with 40 Sukhoi-30 fighter jets across various airbases.
• Submarine-Launched: This variant can be launched from depths of approximately 50 meters below the water surface. The missile, stored in a canister, is vertically launched from the pressure hull of the submarine, employing distinct configurations for underwater and surface flights. Successful testing of this version was first conducted in March 2013 from a submerged platform off the coast of Visakhapatnam

6. Brahmos Missile Series

 

The BrahMos missile series is a family of supersonic cruise missiles developed jointly by India and Russia. Named after the Brahmaputra River in India and the Moskva River in Russia, the BrahMos series is renowned for its speed, precision, and versatility.

Here are some key variants within the BrahMos missile series:

• BrahMos Block-I: The initial variant of the BrahMos missile, featuring a range of approximately 290 km. It is capable of striking both land-based and naval targets with high accuracy.

• BrahMos Block-II: An upgraded version with enhanced capabilities, including improved range and accuracy. It incorporates advanced technologies to further enhance its effectiveness in various operational scenarios.

• BrahMos Block-III: This variant features additional upgrades aimed at improving its range, maneuverability, and stealth capabilities. It is designed to overcome evolving threats and maintain its position as a potent deterrent.

• BrahMos-A: The air-launched variant of the BrahMos missile, integrated onto Sukhoi Su-30MKI fighter aircraft of the Indian Air Force. It significantly extends the reach of the missile, allowing for precision strikes against ground and naval targets.

• BrahMos-N: The naval variant of the BrahMos missile, deployed on Indian Navy warships. It provides a formidable anti-ship and land-attack capability, enhancing the offensive capabilities of naval fleets.

• BrahMos-ER: The extended-range variant of the BrahMos missile, currently under development, aimed at achieving ranges beyond the existing capabilities. It will further enhance the strategic reach of the BrahMos series, allowing for precision strikes at longer distances.

• BrahMos-NG: A next-generation variant of the BrahMos missile, featuring reduced size and weight while maintaining high performance. It is designed for compatibility with a wider range of platforms, including aircraft, submarines, and surface vessels

7.Way Forward

 

BrahMos missile series represents a significant technological achievement in the field of missile development, providing India with a potent and versatile deterrent against various threats. Its continuous evolution and upgrades ensure that it remains at the forefront of modern warfare capabilities

 

 

 

Previous Year Questions 1.Consider the following statements: (UPSC CSE Prelims 2023) Ballistic missiles are jet-propelled at subsonic speeds throughout their flights, while cruise missiles are rocket-powered only in the initial phase of flight. Agni-V is a medium-range supersonic cruise missile, while BrahMos is a solid-fuelled intercontinental ballistic missile. Which of the statements given above is/are correct? 1 only 2 only Both 1 and 2 Neither 1 nor 2 Answer: (d)

Source: Indianexpress

 

 

MARINE HEATWAVES

 

 

 

1. Context

 

In 2023-2024, the world suffered a devastating coral bleaching event during which 84% of the world’s reefs spanning 83 countries and territories were affected. Scientists have since linked the event to ocean warming and marine heatwaves — extended periods of high sea surface temperature than usual.

 

 

2. About marine heat waves

A marine heat wave is an extreme weather event. It occurs when the surface
temperature of a particular region of the sea rises to 3 or 4 degrees Celsius above the
average temperature for at least five days. MHWs can last for weeks, months or
even years. 

 

The impact of marine heat waves on ocean life

• Marine heatwaves (MHWs) have significant and often devastating impacts on ocean life. Despite seemingly minor temperature increases of 3 or 4 degrees Celsius, these events can have catastrophic consequences for marine ecosystems.
• For example, along the Western Australian coast in the summers of 2010 and 2011, MHWs resulted in devastating fish kills, where large numbers of fish and aquatic animals died suddenly and unexpectedly within a short period and were confined to specific areas.
• Moreover, studies have shown that MHWs can lead to the destruction of kelp forests, which play a crucial role in marine ecosystems by providing habitat and food for many marine animals. The increased water temperatures associated with MHWs are detrimental to kelp, which typically thrive in cooler waters.
• Another significant impact of MHWs is coral bleaching, as seen in the tropical Atlantic and Caribbean in 2005.
• During this event, high ocean temperatures caused more than 80 per cent of surveyed corals to bleach, with over 40 per cent ultimately dying.
• Coral bleaching occurs when corals expel the algae living in their tissues, turning them completely white. This phenomenon severely stresses corals, reducing their reproductive capacity and increasing their vulnerability to fatal diseases.
• Since many marine animals rely on coral reefs for survival, damage to corals threatens their existence as well.
• MHWs also contribute to the growth of invasive alien species, which can disrupt marine food webs.
• Additionally, these events force species to alter their behaviour in ways that increase their risk of harm.
• For instance, MHWs have been linked to incidents of whale entanglements in fishing gear, further highlighting the far-reaching consequences of these heatwaves on marine wildlife.

 

 

3. How do Marine Heat Waves Impact Humans?

• Marine heatwaves (MHWs) not only affect marine life but also have significant impacts on humans.
• As ocean temperatures rise during MHWs, storms such as hurricanes and tropical cyclones can become more intense.
• Warmer temperatures lead to increased evaporation and heat transfer from the oceans to the air.
• Consequently, storms travelling across warm oceans gather more water vapour and heat, resulting in stronger winds, heavier rainfall, and more flooding when these storms make landfall.
• This heightened intensity of storms can lead to devastating consequences for human communities in affected areas.
• Furthermore, coral reefs, which are adversely affected by MHWs, are not only essential for marine wildlife but also for human populations.
• According to NOAA, approximately half a billion people rely on reefs for food, income, and protection. When MHWs destroy coral reefs, these human populations are also significantly impacted, facing disruptions to their food sources, livelihoods, and coastal protection.
• The socio-economic impacts of MHWs extend to coastal communities as well. For instance, an MHW over the northwest Atlantic Ocean in 2012 caused marine species accustomed to warmer waters to migrate northward and alter their migration patterns earlier than usual.
• This shift affected fisheries targeting these species in the United States, resulting in economic losses and disruptions to local communities.
• As global temperatures continue to rise, MHWs are projected to become more frequent, intense, and prolonged, exacerbating their adverse effects on both marine ecosystems and human societies.

 

4. Global warming affecting marine heat waves and oceans

• Global warming, driven by the increase in greenhouse gas emissions, is profoundly affecting marine heatwaves (MHWs) and the overall health of oceans. Studies, including one published in the journal Nature in 2018 titled 'Marine heatwaves under global warming,' reveal alarming trends.
• Over recent decades, MHWs have become longer-lasting, more frequent, and more intense due to soaring global temperatures. Between 1982 and 2016, the study found a doubling in the number of MHW days, with projections indicating a further increase by a significant factor under various warming scenarios.
• Crucially, the study attributes 87 per cent of MHWs to human-induced warming, emphasizing the direct link between anthropogenic activities and the intensification of marine heatwaves. This intensification is exacerbated by the oceans' role in absorbing approximately 90 per cent of the additional heat generated by greenhouse gas emissions since the Industrial Revolution.
• As a result, global mean sea surface temperatures have risen by nearly 0.9 degrees Celsius since 1850, with a notable increase of around 0.6 degrees Celsius over the last four decades alone.
• With global air temperatures on the rise, ocean temperatures are also increasing, leading to the escalation of MHWs. Compounding this issue, the onset of El Nino conditions, characterized by abnormal warming of surface waters in the equatorial Pacific Ocean, is further exacerbating heat extremes.
• Scientists warn that El Nino events are likely to intensify extreme heat events and could potentially break temperature records in various regions worldwide.
• The unprecedented impact of concurrent phenomena such as soaring global air and ocean temperatures, increased MHWs, and record-low Antarctic sea ice levels. The uncertainties regarding the future consequences of these trends, emphasise the urgent need for proactive measures to mitigate the escalating risks posed by climate change on marine ecosystems and human societies.

 

5. The Way Forward

 

Marine heatwaves are a serious threat to both marine ecosystems and human societies. Understanding the causes and consequences of MHWs is crucial for taking proactive measures to address climate change and protect our oceans and ourselves.

 

 

For Prelims: Marine Heatwaves, Coral Reefs, El Nino, Climate Change,  For Mains:  1. Explain the relationship between global warming and the increasing frequency and intensity of  Marine heat waves (MHWs). Assess the potential socio-economic and ecological repercussions of this phenomenon in the Arctic region. (250 words) 2.  Discuss the ethical implications of human activities contributing to Marine heat waves (MHWs) and the disproportionate impact they have on vulnerable coastal communities. (250 words) 3.  Imagine you are heading a national task force responsible for developing a comprehensive strategy to address Marine heat waves (MHWs). Outline your key priorities and action plan, taking into account scientific evidence, public participation, and sustainable solutions. (250 words)

 

Previous Year Questions   1. Consider the following statements: (UPSC 2022) 1. High clouds primarily reflect solar radiation and cool the surface of the Earth. 2. Low clouds have a high absorption of infrared radiation emanating from the Earth's surface and thus cause a warming effect. 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     2. What are the possible limitations of India in mitigating global warming at present and in the immediate future? (UPSC 2010) 1. Appropriate alternate technologies are not sufficiently available. 2. India cannot invest huge funds in research and development. 3. Many developed countries have already set up their polluting industries in India. Which of the statements given above is/are correct? A. 1 and 2 only            B. 2 only              C. 1 and 3 only                  D. 1, 2 and 3   Answers: 1-D, 2-A

 

 Source: The Indian Express

 

GREENHOUSE GASES(GHGs)

 

 

1. Context

 

Everybody has their favorite way of travelling. Usually, the choice of the mode of transport is driven by convenience, comfort, and cost. But things are changing around the world for a completely different reason. There is growing interest in what experts call a “modal shift” — moving people and goods from roads and flights to railways — that could have a big impact on the environment, traffic, and even the economy

 

2.What are greenhouse gases?

 

Greenhouse gases are gases that trap heat in the Earth's atmosphere, leading to the greenhouse effect and contributing to global warming. These gases include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ozone (O3), and fluorinated gases (such as hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, and nitrogen trifluoride).

These gases allow sunlight to enter the Earth's atmosphere freely. Once absorbed, the Earth's surface emits infrared radiation, but instead of allowing this radiation to escape back into space, greenhouse gases trap and re-radiate some of it back towards the Earth's surface. This process warms the Earth's surface and lower atmosphere, leading to the greenhouse effect.

Human activities, such as the burning of fossil fuels, deforestation, and industrial processes, have significantly increased the concentration of greenhouse gases in the atmosphere, amplifying the greenhouse effect and contributing to global climate change

Here are the major greenhouse gases:

• Carbon dioxide (CO2): The most abundant greenhouse gas emitted through human activities. It is released when fossil fuels like coal, oil and natural gas are burned
• Methane (CH4): Methane is emitted from agriculture, waste decomposition, and fossil fuel production. It is a more potent greenhouse gas than CO2, but it breaks down in the atmosphere more quickly
• Nitrous oxide (N2O): Nitrous oxide is emitted from agriculture, industrial processes, and burning fossil fuels. It is a long-lived greenhouse gas that can stay in the atmosphere for centuries
• Fluorinated gases These are man-made chemicals used in refrigerants, air conditioners, and fire extinguishers. They are very potent greenhouse gases, but they are emitted in much smaller quantities than other greenhouse gases
• Water vapor (H2O): The most abundant greenhouse gas in the atmosphere. Water vapor plays an important role in the natural greenhouse effect, but human activities do not significantly affect the amount of water vapor in the atmosphere

3. What is the Greenhouse gas effect?

The greenhouse effect is a natural process that occurs when certain gases in the Earth's atmosphere trap heat from the sun. This process is essential for maintaining the Earth's temperature within a range suitable for life. Without the greenhouse effect, the Earth would be much colder, and life as we know it would not exist.

Here's how the greenhouse effect works:

• Solar radiation: Sunlight reaches the Earth's atmosphere and passes through it, warming the Earth's surface.

• Absorption and re-radiation: The Earth's surface absorbs some of this solar energy and then emits it as infrared radiation (heat). Greenhouse gases in the atmosphere, such as carbon dioxide (CO2), methane (CH4), water vapor (H2O), and others, absorb some of this infrared radiation.

• Re-emission: The absorbed energy is re-radiated in all directions, including back toward the Earth's surface. This trapped heat warms the lower atmosphere and the Earth's surface, similar to how a greenhouse traps heat.

• Balance: The greenhouse effect helps maintain the Earth's temperature in a range suitable for life. However, human activities, such as burning fossil fuels and deforestation, have significantly increased the concentration of greenhouse gases in the atmosphere, leading to enhanced greenhouse effect or global warming

 

4. What are hydrofluorocarbons?

 

• Hydrofluorocarbons (HFCs) are a class of synthetic greenhouse gases commonly used in refrigeration, air conditioning, foam blowing agents, aerosol propellants, and other industrial applications. They are composed of hydrogen, fluorine, and carbon atoms.
• HFCs were developed as alternatives to chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), which were phased out due to their significant ozone-depleting potential. Unlike CFCs and HCFCs, HFCs do not contain chlorine atoms, so they do not contribute to ozone depletion.
• However, they are potent greenhouse gases, with high global warming potentials (GWPs), meaning they trap heat in the atmosphere at a much higher rate than carbon dioxide (CO2).
• Due to their role in contributing to climate change, efforts have been made internationally to regulate and phase out the use of HFCs. The Kigali Amendment to the Montreal Protocol, adopted in 2016, aims to gradually reduce the production and consumption of HFCs globally.
• Many countries are transitioning to alternative refrigerants with lower global warming potentials, such as hydrofluoroolefins (HFOs) and natural refrigerants like ammonia and carbon dioxide. These efforts are essential for mitigating climate change by reducing the emissions of potent greenhouse gases like HFC

5. What are the adverse effects?

 

The greenhouse gas effect, when intensified beyond natural levels due to human activities, leads to a range of adverse effects on the environment, ecosystems, and human societies.

 

Some of these effects include:

• The primary consequence of intensified greenhouse gas effect is global warming. Increased concentrations of greenhouse gases in the atmosphere trap more heat, leading to a rise in average global temperatures
• Global warming alters weather patterns and climatic conditions worldwide, leading to changes such as more frequent and intense heatwaves, storms, droughts, and floods. These changes can disrupt ecosystems, agriculture, and water supplies, leading to ecological imbalances and economic losses
• Warmer temperatures cause polar ice caps and glaciers to melt, contributing to rising sea levels. This phenomenon threatens coastal communities, low-lying islands, and habitats, increasing the risk of flooding and erosion
•  Increased atmospheric CO2 levels lead to higher levels of carbon dioxide dissolving into oceans, resulting in ocean acidification. This harms marine life, particularly organisms with calcium carbonate shells or skeletons, such as corals, mollusks, and certain plankton species
• Climate change disrupts ecosystems and habitats, forcing species to migrate, adapt, or face extinction. The rapid pace of climate change often outpaces the ability of many species to adapt, leading to biodiversity loss and ecosystem degradation
• Climate change exacerbates health risks, including heat-related illnesses, respiratory problems from poor air quality, increased prevalence of infectious diseases, and food and water insecurity due to changing agricultural conditions
• Climate change can lead to displacement of populations due to extreme weather events, loss of livelihoods in sectors such as agriculture and fishing, and increased conflicts over resources like water and arable land. These disruptions can strain social systems and economies, particularly in vulnerable regions

6.What is Montreal Protocol?

 

The Montreal Protocol is an international environmental agreement aimed at protecting the Earth's ozone layer by phasing out the production and consumption of ozone-depleting substances (ODS). It was negotiated in 1987 and entered into force in 1989. The protocol is regarded as one of the most successful international environmental treaties.

Key points about the Montreal Protocol include:

• Objective: The primary goal of the Montreal Protocol is to phase out the production and consumption of ODS, which are substances that contain chlorine and bromine atoms and are responsible for ozone depletion in the stratosphere.

• Ozone Layer: The ozone layer is a region of the Earth's stratosphere that contains a high concentration of ozone molecules (O3). This layer plays a crucial role in absorbing and filtering out harmful ultraviolet (UV) radiation from the sun, protecting life on Earth from its harmful effects.

• Ozone-Depleting Substances: The Montreal Protocol targets several categories of ODS, including chlorofluorocarbons (CFCs), halons, carbon tetrachloride, and methyl chloroform, among others. These substances were commonly used in refrigeration, air conditioning, foam blowing agents, fire extinguishers, and other industrial applications.

• Phasing Out: The protocol established a timetable for phasing out the production and consumption of ODS, with developed countries committing to earlier phase-out schedules and developing countries given more time to comply. Amendments to the protocol tightened regulations and accelerated the phase-out schedules over time.

• Success: The Montreal Protocol is widely regarded as successful in achieving its objectives. By reducing the production and consumption of ODS, the protocol has led to a gradual recovery of the ozone layer. Scientific assessments have confirmed a decrease in the atmospheric concentrations of ODS and a healing of the ozone layer.

• International Cooperation: The Montreal Protocol exemplifies successful international cooperation in addressing global environmental challenges. It has been ratified by almost every country in the world, demonstrating a shared commitment to protecting the ozone layer and mitigating climate change (as many ODS are also potent greenhouse gases)

7.Way Forward

 

Since 2020, the US has banned the import of HCFC 22 for any purpose other than in a process which results in its transformation or destruction. The American Innovation and Manufacturing (AIM) Act, passed by Congress in December 2020, authorised the US Environmental Protection Agency (EPA) to phase down the production and consumption of numerous forms of HFCs

 

 

For Prelims: General issues on Environmental ecology, Bio-diversity and Climate Change – that do not require subject specialization For Mains: General Studies III: Conservation, environmental pollution and degradation, environmental impact assessment

 

 

Previous Year Questions   1.Global warming is attributed to the presence of the following gases in the atmosphere : (UGC NET 2022) (A) Methane (B) Sulphur dioxide (C) Surface Ozone (D) Nitrogen dioxide (E) Carbon dioxide Choose the correct answer from the options given below : 1.(A), (B), (C), (E) only 2.(A), (C), (E) only 3.(A), (C), (D), (E) only 4.(A), (B), (D), (E) only Answer (2)

Source: Indianexpress