HPAS 2014 Environment & Ecology Solutions

India has a total of 18 officially notified Biosphere Reserves under the National Programme. Out of these, exactly 13 Biosphere Reserves are internationally recognized under UNESCO’s Man and the Biosphere (MAB) Programme (with the Cold Desert Biosphere Reserve being the latest inclusion).

Complete List of India’s 18 Biosphere Reserves & Their UNESCO MAB Status

1. Nilgiri (1986) – Tamil Nadu, Kerala, Karnataka (India’s First BR; UNESCO MAB since 2000)
2. Nanda Devi (1988) – Uttarakhand (UNESCO MAB since 2004)
3. Nokrek (1988) – Meghalaya (UNESCO MAB since 2009)
4. Gulf of Mannar (1989) – Tamil Nadu (UNESCO MAB since 2001)
5. Sundarbans (1989) – West Bengal (UNESCO MAB since 2001)
6. Manas (1989) – Assam (Not in UNESCO MAB)
7. Great Nicobar (1989) – Andaman & Nicobar Islands (UNESCO MAB since 2013)
8. Similipal (1994) – Odisha (UNESCO MAB since 2009)
9. Dibru-Saikhowa (1997) – Assam (Smallest BR; Not in UNESCO MAB)
10. Dehang-Dibang (1998) – Arunachal Pradesh (Not in UNESCO MAB)
11. Pachmarhi (1999) – Madhya Pradesh (UNESCO MAB since 2009)
12. Khangchendzonga (2000) – Sikkim (UNESCO MAB since 2018)
13. Agasthyamalai (2001) – Kerala, Tamil Nadu (UNESCO MAB since 2016)
14. Achanakmar-Amarkantak (2005) – Madhya Pradesh, Chhattisgarh (UNESCO MAB since 2012)
15. Great Rann of Kutch (2008) – Gujarat (Largest BR; Not in UNESCO MAB)
16. Cold Desert (2009) – Himachal Pradesh (UNESCO MAB since 2025)
17. Seshachalam Hills (2010) – Andhra Pradesh (Not in UNESCO MAB)
18. Panna (2011) – Madhya Pradesh (UNESCO MAB since 2020)

Summary for Exams:

• Total Nationally Notified: 18
• Total in UNESCO MAB Network: 13
  (Nilgiri, Gulf of Mannar, Sundarbans, Nanda Devi, Nokrek, Pachmarhi, Simlipal, Achanakmar-Amarkantak, Great Nicobar, Agasthyamalai, Khangchendzonga, Panna, and Cold Desert)
• The 5 Reserves NOT part of UNESCO MAB: Manas, Dibru-Saikhowa, Dihang-Dibang, Great Rann of Kutch, and Seshachalam Hills.

The correct answer is (c) 1994. While opened for signature at the 1992 Rio Earth Summit, India officially ratified the treaty on February 18, 1994.

The provided answer is correct. While Carbon Dioxide (CO₂) is the most abundant anthropogenic greenhouse gas, Methane is the second most significant contributor to global climate change. Here is the targeted breakdown for your preliminary exams:

Relevance for Prelims: Methane (The Correct Answer)

• Global Warming Potential (GWP): Methane (CH₄) is an extremely potent greenhouse gas. Over a 20-year period, it is roughly 80 times more effective at trapping heat in the atmosphere than CO₂, though it has a much shorter atmospheric lifespan (around 12 years).
• Major Anthropogenic Sources (Highly Tested): The most frequently asked sources in exams are paddy fields (rice cultivation), enteric fermentation in ruminant livestock (cattle/sheep belching), landfills, and the extraction/transport of fossil fuels (natural gas leaks).
• Natural Sources: Wetlands are the largest natural source of atmospheric methane globally.
• Current Affairs Link: The Global Methane Pledge (launched at COP26) aims to reduce global methane emissions by at least 30% from 2020 levels by 2030. Key Fact: India is currently not a signatory to this pledge, citing concerns over impacts on its agricultural sector.

Relevance for Prelims: Analysis of Other Options (Exam Traps)

• (b) Nitrogen dioxide (NO₂): Exam Trap! The major greenhouse gas is Nitrous Oxide (N₂O), commonly known as laughing gas. Nitrogen dioxide (NO₂) is primarily a local air pollutant responsible for photochemical smog and acid rain, though it is not classified as a primary greenhouse gas.
• (c) Sulphur dioxide (SO₂): This gas actually has a cooling effect on the climate. In the atmosphere, SO₂ forms sulphate aerosols that reflect incoming solar radiation back into space (increasing Earth’s albedo). However, it is a major pollutant because it mixes with water vapor to form Acid Rain (sulfuric acid).
• (d) Helium: A noble, inert gas. It does not absorb infrared radiation and therefore plays absolutely no role in the greenhouse effect or climate change.

The provided answer is correct. China is currently the world’s largest annual emitter of Carbon Dioxide (CO₂), primarily due to its massive industrial base and reliance on coal for electricity generation. Here is the targeted breakdown of global emission data for your preliminary exams:

Relevance for Prelims: Annual vs. Per Capita vs. Historical Emissions (Highly Tested)

• Total Annual Emissions (Current): The top four emitters in absolute terms are 1. China, 2. USA, 3. India, 4. Russia. China alone accounts for roughly a third of all global annual CO₂ emissions.
• Per Capita Emissions (The Exam Trap): While China leads in total emissions, its per capita (per person) emissions are roughly half those of the USA. India’s per capita emissions remain significantly below the global average. This metric forms the bedrock of India’s stance in climate negotiations, emphasizing the principle of “Common but Differentiated Responsibilities” (CBDR).
• Historical/Cumulative Emissions: Since the onset of the Industrial Revolution (around 1850), the USA is by far the largest historical emitter, followed by the European Union and China. India is responsible for only about 4% of historical global emissions, meaning it has contributed very little to the cumulative atmospheric carbon budget.

Relevance for Prelims: Key Climate Targets (Net Zero)

• Divergent Net Zero Timelines: Civil service exams frequently test the different Net Zero target years declared by major emitters. The USA and EU have committed to Net Zero by 2050, China by 2060, and India (as announced under the Panchamrit strategy at COP26) by 2070.

The provided answer is correct. The Intergovernmental Panel on Climate Change (IPCC) 4th Assessment Report (AR4), published in 2007, confirmed this specific historical rate. Here is the targeted breakdown of sea-level rise mechanisms and IPCC facts for your preliminary exams:

Relevance for Prelims: Primary Drivers of Sea Level Rise

• Thermal Expansion: As the ocean absorbs excess atmospheric heat caused by greenhouse gases, the water warms and physically expands. For the period of 1961-2003, thermal expansion was responsible for the largest share of the observed sea-level rise.
• Melting of Land-Based Ice: The secondary major driver is the melting of mountain glaciers, ice caps, and the massive polar ice sheets (Greenland and Antarctica), which adds new water mass to the ocean basins. Note: Melting of sea ice (like in the Arctic Ocean) does not directly raise global sea levels, just as a melting ice cube does not overflow a glass of water.

Relevance for Prelims: IPCC Organization & Historical Facts

• Founding & Parent Bodies: The IPCC was established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP). It does not conduct its own original research; rather, it synthesizes published scientific literature.
• The Nobel Prize (Highly Tested): The IPCC was jointly awarded the 2007 Nobel Peace Prize (along with Al Gore) specifically for the global awareness generated by this exact 4th Assessment Report (AR4).

Relevance for Prelims: Updated Data from AR6 (The Current Trend)

• Accelerating Rates: Exams often test the trajectory of these changes. According to the most recent IPCC 6th Assessment Report (AR6), the rate of global mean sea level rise has significantly accelerated, reaching approximately 3.7 mm per year for the period of 2006–2018, more than double the historical rate asked in this question.

The provided answer is correct. Based on recent India State of Forest Reports (ISFR), the actual forest cover is approximately 21.71%, making 21% the most accurate option. Here is the highly targeted breakdown of forest data for your preliminary exams:

Relevance for Prelims: Forest vs. Tree Cover (ISFR 2021 Data)

• Forest Cover vs. Total Cover: Exams frequently test this distinction. The Forest Cover alone is 21.71%. However, if a question specifically asks for the Total Forest AND Tree Cover, the figure is 24.62%.
• The 33% Target: According to the National Forest Policy of 1988, the ideal target for environmental stability in India is to have at least one-third (33%) of the total geographical area under forest or tree cover (and 66% in hilly/mountainous regions).

Relevance for Prelims: State-Wise Rankings (Highly Tested)

• Largest by Total Area: Madhya Pradesh has the largest total forest cover in the country, followed by Arunachal Pradesh and Chhattisgarh.
• Largest by Percentage: When measured as a percentage of the state’s own geographical area, Mizoram leads the country (approx. 84.53%), followed by Arunachal Pradesh and Meghalaya.

Relevance for Prelims: HPAS Specific Forest Data

• Himachal Pradesh: The actual forest cover of Himachal Pradesh is approximately 27.73% of its total geographical area. Key distinction: The legally classified “Recorded Forest Area” is much higher (over 68%), but a significant portion of this consists of permanently snow-covered areas, cold deserts (Lahaul & Spiti), and alpine pastures above the tree line where forests cannot physically grow.

The provided answer is correct. Solar energy is the primary driving force and ultimate engine for all natural ecosystems on Earth, powering biogeochemical cycles and energy flow. Here is the targeted breakdown of these core ecological concepts for your preliminary exams:

Relevance for Prelims: Solar Energy (The Driving Force)

• Photosynthetically Active Radiation (PAR): Out of the total incident solar radiation reaching the Earth, less than 50% falls in the PAR wavelength range (400–700 nm). Plants capture only 2–10% of PAR (which translates to just 1–5% of total incident solar energy) to sustain all life on Earth.
• Unidirectional Flow: Energy enters an ecosystem strictly through solar radiation and flows sequentially up through trophic levels. Unlike nutrients (which cycle continuously through biogeochemical pathways), energy never recycles; it continuously degrades and dissipates as metabolic heat according to the Second Law of Thermodynamics.

Relevance for Prelims: Analysis of Other Options

• (b) Vegetation & (c) Producers: These autotrophs act as the biological converters that capture solar energy, but they are not the independent driving force itself. Key Exam Concepts:
  • Gross Primary Productivity (GPP): The total rate at which producers capture solar energy and synthesize organic matter.
  • Net Primary Productivity (NPP): The organic matter remaining after accounting for respiratory losses ($R$) by plants ($NPP = GPP – R$). This $NPP$ is the actual biomass available for consumption by herbivores.
• (d) Biomass: Refers to the total mass or dry weight of living organic material present in a specific trophic level at a given time (termed the Standing Crop). High-Yield Exam Trap: While the Pyramid of Biomass is upright in most terrestrial ecosystems, it is inverted in aquatic ecosystems (e.g., oceans/ponds) because a tiny standing crop of phytoplankton supports a much larger biomass of zooplankton and fish due to rapid turnover rates.

The provided answer is correct based on the principle of latitudinal biodiversity gradients. While coral reefs are the most diverse marine ecosystems, tropical regions as a whole (particularly tropical rainforests) harbor the absolute highest total global biodiversity. Here is the targeted breakdown for your preliminary exams:

Relevance for Prelims: Tropical Regions (The Correct Answer)

• Latitudinal Gradient: As a fundamental rule of ecology, biodiversity consistently increases as you move from the poles toward the equator. The tropics (between 23.5° N and 23.5° S) host significantly more species than temperate or polar zones.
• Why Maximum Diversity?: Tropical environments have remained relatively undisturbed by past historical glaciations, granting millions of years of evolutionary time for species diversification. Additionally, they receive more constant, direct solar energy and rainfall, resulting in massive primary productivity and complex food webs (e.g., the Amazon Rainforest).

Relevance for Prelims: Analysis of Other Highly Diverse Ecosystems

• (b) Coral Reefs (Frequent Exam Trap): Often termed the “Rainforests of the Sea.” They hold the maximum biodiversity among all marine ecosystems, despite covering less than 0.1% of the ocean floor. If a question specifically asks for the marine ecosystem with the highest diversity, the answer is coral reefs.
• (a) Mangroves: An extremely critical Ecotone (a transitional ecosystem between marine and terrestrial environments). Because of the Edge Effect, ecotones inherently support high biodiversity. They also serve as vital nurseries for coastal fish and protect shorelines from tsunamis.
• (c) Temperate Regions: These regions experience severe seasonal climatic changes and were subjected to historical glaciations (ice ages) in the past, which wiped out many species and limited their evolutionary diversification compared to the tropics.

The provided answer is correct. Despite the global push for renewable energy, fossil fuels (coal, petroleum oil, and natural gas) still dominate the world’s primary energy consumption, accounting for roughly 80% of the global energy mix. Here is the targeted breakdown for your preliminary exams:

Relevance for Prelims: Fossil Fuels (Global and Indian Context)

• India’s Power Sector: India’s energy security remains heavily reliant on Coal (Thermal Power). Coal alone accounts for roughly 50% of India’s total installed power generation capacity and an even higher percentage of actual electricity generated.
• Strategic Petroleum Reserves (SPR): Because India imports over 80% of its crude oil, it maintains underground SPR facilities at Visakhapatnam, Mangaluru, and Padur (with expansions planned at Chandikhol and Bikaner) to mitigate global supply shocks.
• The Transition Targets: Under its updated Nationally Determined Contributions (NDCs) and the Panchamrit strategy, India aims to achieve 500 GW of non-fossil fuel energy capacity by 2030 to gradually shift away from this fossil fuel dependence.

Relevance for Prelims: Analysis of Other Energy Sources (HPAS Specifics)

• (a) Hydropower (HPAS Favorite): While not the global primary source, hydropower is the absolute backbone of Himachal Pradesh’s economy. The state has an estimated hydel potential of over 27,000 MW (about 25% of India’s total potential). Major river basin projects on the Sutlej, Beas, and Ravi are guaranteed exam topics. Globally, it remains the largest source of renewable electricity.
• (c) Nuclear Power: Currently contributes under 3% to India’s energy mix. Exams often test India’s unique Three-Stage Nuclear Power Programme (envisioned by Homi Bhabha), which ultimately aims to bypass uranium shortages by utilizing India’s vast domestic Thorium reserves (found in the monazite sands of Kerala coastal regions).
• (d) Solar Power: The fastest-growing renewable source. For exam purposes, remember that India jointly launched the International Solar Alliance (ISA) with France (headquartered in Gurugram, Haryana). Massive installations like the Bhadla Solar Park (Rajasthan) and Rewa Ultra Mega Solar (Madhya Pradesh) are frequent current affairs questions.

The provided answer is correct. September 16 is designated by the United Nations as the International Day for the Preservation of the Ozone Layer. Here is the highly targeted breakdown of ozone chemistry and related treaties for your preliminary exams:

Relevance for Prelims: The Montreal Protocol (The September 16 Connection)

• Historical Significance: September 16 commemorates the exact date in 1987 when nations signed the Montreal Protocol on Substances that Deplete the Ozone Layer. It is widely considered the most successful multilateral environmental agreement in UN history, being the first treaty to achieve universal ratification.
• Targeted Substances (ODS): The protocol mandated the global phase-out of Ozone Depleting Substances, primarily Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, and carbon tetrachloride, which were once widely used in refrigeration, air conditioning, and aerosols.
• The Kigali Amendment (Highly Tested): Adopted in 2016 (and ratified by India), this crucial amendment to the Montreal Protocol aims to phase down Hydrofluorocarbons (HFCs). Exam Trap: HFCs do not actually deplete the ozone layer, but they were included under this treaty because they are extremely potent greenhouse gases that were introduced as replacements for CFCs.

Relevance for Prelims: Science of the Ozone Layer (Key Geographical Facts)

• “Good” vs. “Bad” Ozone: Exams frequently test atmospheric layers.
  • Stratospheric Ozone (“Good”): Found 10–50 km above the Earth’s surface. It protects terrestrial life by absorbing lethal Ultraviolet-B and C (UV-B and UV-C) solar radiation.
  • Tropospheric Ozone (“Bad”): Ground-level ozone is a toxic secondary pollutant formed by the reaction of sunlight with nitrogen oxides (NOx) and volatile organic compounds (VOCs). It is a primary component of dangerous photochemical smog.
• Measurement Unit: The total thickness of the ozone layer in a column of air is measured in Dobson Units (DU).
• The “Ozone Hole”: The severe depletion of the ozone layer is most prominent over Antarctica during the Southern Hemisphere’s spring (September to November). This unique geographical phenomenon is driven by the formation of Polar Stratospheric Clouds (PSCs) in extreme cold, which provide a surface for chlorine and bromine to rapidly destroy ozone molecules once sunlight returns.