Environment and Ecology: UPSC Previous Year Questions (Prelims)

Explanation

Biodiversity provides a number of natural services for human beings which are listed in the table below:

Ecosystem Services Protection of water resources Soil formation and protection Nutrient storage and recycling Pollution breakdown and absorption Contribution to climate stability Maintenance of ecosystems Recovery from unpredictable events Biological Services Food Medicinal resources and pharmaceutical drugs Wood products Ornamental plants Pollination of crops Breeding stocks Diversity in genes, species and ecosystems Social Services Research, education and monitoring Recreation and tourism Cultural values

Explanation

Being a confluence of different biogeographical zones Himalayan Range is very rich in species diversity. The Himalayas act as a natural transition zone between several major bio-geographical regions, leading to high species diversity and endemism. There are ten biogeographic zones in India:

1. Trans-Himalayan zone. 2. Himalayan zone

3. Desert zone. 4. Semi Arid zone.

5. Western ghat zone. 6. Deccan plateau zone.

7. Gangetic plain zone. 8. North east zone.

9. Coastal zone 10. Islands

Explanation

Micro-irrigation is the slow distribution of water to the soil using surface drip and micro-sprinkler systems in the form of discrete or continuous drips, tiny streams, or miniature spray. Benefits of micro irrigation systems: Helps in water-saving and checking further depletion, Increased irrigation efficiency, Higher yields, Less water loss, Energy efficient, Lower consumption of fertilizers, Weed and disease reduction, Cost savings, Precision farming.

Statement 1 is correct: An efficient drip irrigation system reduces the consumption of fertiliser through fertigation.

Statement 2 is incorrect: Dryland farming is defined as the production of crops without irrigation in regions that receive rainfall of less than 500mm annually. Crop selection, Microcatchments and Runoff farming are some other methods of irrigation in dry-land farming.

Statement 3 is correct: Micro-irrigation helps in water-saving and checking further groundwater depletion.

Explanation

A rapid rise in the population of algae in an aquatic system is known as an algal bloom, marine bloom, or water bloom. Algal blooms can appear in both marine and freshwater habitats. "Harmful algal blooms (HAB)" are blooms that can affect wildlife or the environment. Harmful Algal Bloom can lead to fish die-offs, cities cutting off water to residents, or states having to close fisheries.

Statement 1 is correct: Estuaries receive nutrient-rich water from rivers which can include agricultural runoff, sewage, and industrial effluents. These nutrients, particularly nitrogen and phosphorus promote the growth of algae causing algal blooms.

Statement 2 is correct: Heavy rainfall during the monsoon season can cause significant runoff from agricultural fields, urban areas, and other land surfaces. This runoff can carry fertilizers, pesticides, and other nutrients into the sea, providing the necessary conditions for algal blooms

Statement 3 is correct: Water that rises to the surface as a result of upwelling is typically colder and is rich in nutrients, which again leads to algal blooms.

Explanation

For slowing down global warming, carbon sequestration involves the capture and storage of CO₂. It is captured from the air, industries or power stations and stored permanently underground. This promotes Long-term reserve of CO₂ or forms of carbon to control temperatures. Carbon sequestration aids in lowering the amount of GHGs (due to combustion of fossil fuels) present in the air.

Statement 2 is correct: The photosynthesis by phytoplankton in the oceans is natural carbon sequestration and it is responsible for much of CO₂ being moved from lower atmosphere to oceans:

Statements 1 is incorrect: CO₂ is a heavy gas that primarily accumulates in the troposphere and lower stratosphere but does not escape into the outer stratosphere or space. The primary removal mechanisms of CO₂ involve absorption by oceans, photosynthesis by plants, and geological sequestration rather than atmospheric escape. Statements 3 is incorrect: Polar ice caps and glaciers are not a major active carbon sink. Ice trapping does not remove a significant amount of CO₂ from the atmosphere on short time scales. While some CO₂ gets sealed in glaciers but melting due to climate change can release CO₂ back into the atmosphere thereby making this process less effective in long-term carbon storage.

Explanation

Emissions of all the above-mentioned gases i.e. Carbon dioxide, Oxides of Nitrogen and Oxides of Sulphur take place from coal combustion at thermal power plants. Gas Sources Carbon dioxide (CO₂) Burning of fossil fuels, deforestation Oxides of Sulphur Burning fossil fuels, Smelting ores, Volcanic eruptions, Vehicles, etc Nitrogen oxides (N₂O) Burning of fossil fuels, fertilizers; burning of wood and crop residue. Carbon Monoxide (CO) Iron ore smelting, burning of fossil fuels, burning e-waste.

Explanation

Antarctic Ozone Hole was discovered by British Antarctic Survey scientists Farman, Gardiner and Shanklin in 1985. The formation of the ozone hole in the Antarctic has been an annual occurrence (in the months of September, October and November, due to a set of special meteorological and chemical conditions that arise at the South Pole, such as the presence of strong polar front, polar stratospheric clouds and increasing inflow of human-made chemicals like CFCs, etc.

Explanation

Carbon Credit is a permit that allows the company the right to emit 1 tonne of CO₂ or its equivalent. One credit permits the emission of a mass equal to one ton of carbon dioxide. Statement (a) is correct: The carbon credit system was established as part of the Kyoto Protocol (1997) to allow countries to meet their emission reduction targets via flexible mechanisms such as Carbon Trading, Clean Development Mechanism (CDM), etc. Statement (b) is correct: Under Kyoto mechanisms, countries or entities that emit less than their allowed quota can earn carbon credits, which they can then sell to others who are exceeding limits. Statement (c) is correct: The core objective is to create a market-based incentive to limit global greenhouse gas emissions, especially CO₂. Statement (d) is incorrect: Carbon credit prices are not fixed by UNEP (United Nations Environment Programme). They are determined by market forces in various carbon exchanges, such as the European Union Emission Trading Scheme (EU-ETS). UNEP does not set or fix prices.

Explanation

The Indian Forest Act, 1927 This Act provides the legal framework for the management and protection of forests in In-dia. By regulating the use of forest resources, it directly contributes to the conservation of biodiversity within forest ecosystems. In order to increase accountability for forest protection, this act lays out the steps that must be taken when designating a region as a Reserved Forest, Protected Forest, or Village Forest. Import and Ex-port (Control) Act, 1947 This Act regulates the import and export of goods, including wildlife and plant species. By controlling trade, it helps prevent the exploitation and illegal trafficking of endangered species, thereby contributing to biodiversity conservation. Mining and Mineral Development (Regulation) Act 1957 Mining activities, whether occurring within or near Protected Areas, cause a range of environmental consequences that can be severe and irreversible. Thus mining is restricted in reserved areas. Customs Act, 1962 Import and export of GMOs or exotic species are strictly regulated whereas certain medicinal plants are subjected to high customs duties to regulate their trade.

Explanation

The Indian wild ass also known as the Ghudkhur, is native to the Rann of Kutch in Gujarat, India. This region is characterized by sandy and saline desert conditions, which are the natural habitat of the Indian wild ass. The species has no natural predators in this area, but its survival is threatened due to habitat destruction, human encroachment, and competition for resources. It is listed under Schedule I of the Wildlife Protection Act of 1972. Listed as Near Threatened in the IUCN’s Red List of Threatened Species.