UPSC Geoscientist Archives

21. India has committed to reduce emission intensity of its GDP from 2005

India has committed to reduce emission intensity of its GDP from 2005 levels by 33-35 per cent by the year:

2022

2030

2032

2035

This question was previously asked in

UPSC Geoscientist – 2020

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The correct answer is 2030.

India’s first Nationally Determined Contribution (NDC) under the Paris Agreement included a commitment to reduce the emission intensity of its GDP by 33-35 per cent from 2005 levels by the year 2030.

In 2022, India updated its NDC, enhancing the emission intensity reduction target to 45 per cent from 2005 levels by 2030. However, the question refers to the initial 33-35 per cent commitment, which was set for 2030.

22. Pursuant to the ratification of Convention on Biological Diversity, In

Pursuant to the ratification of Convention on Biological Diversity, India legislated Biodiversity Act in the year:

1992

1994

2002

2014

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India ratified the Convention on Biological Diversity (CBD) in 1993. Following its commitments under the CBD, India enacted its own national legislation, the Biological Diversity Act, in the year 2002.

– The Biological Diversity Act, 2002, aims to conserve biological diversity, ensure sustainable use of its components, and facilitate fair and equitable sharing of benefits arising from the use of biological resources and associated knowledge.
– It established a three-tier structure: the National Biodiversity Authority (NBA) at the national level, State Biodiversity Boards (SBBs) at the state level, and Biodiversity Management Committees (BMCs) at the local level.
– The Act regulates access to biological resources and traditional knowledge by foreign nationals, companies, and Indian entities.

– The Convention on Biological Diversity (CBD) was opened for signature at the Earth Summit in Rio de Janeiro in 1992 and entered into force in December 1993.
– The Act reflects India’s sovereign rights over its biological resources and the principles of the CBD regarding conservation, sustainable use, and benefit-sharing.

23. Greenhouse gases are known so as:

Greenhouse gases are known so as:

they trap heat in the high altitudes.

they act like a greenhouse on the surface of the planet.

the colour of some of the gases emanating from industrial plants are green.

these gases are produced by agricultural crops.

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Greenhouse gases are so named because they trap heat in the Earth’s lower atmosphere in a manner analogous to how the glass walls and roof of a greenhouse trap heat.

– Greenhouse gases (such as CO₂, methane, water vapor) are transparent to incoming solar radiation (shortwave).
– The Earth’s surface absorbs this radiation and re-emits energy as infrared radiation (longwave heat).
– Greenhouse gases absorb this outgoing infrared radiation and re-emit it in all directions, including back towards the Earth’s surface, thus trapping heat and warming the planet.

– This process is known as the greenhouse effect, a natural phenomenon essential for maintaining a habitable temperature on Earth.
– An increase in the concentration of greenhouse gases due to human activities enhances this effect, leading to global warming and climate change.
– The analogy with a greenhouse is not perfect (a real greenhouse also traps heat by preventing convective heat loss), but it effectively describes the trapping of infrared radiation.

24. Farmers surround the fields with hedgerows during high insolation peri

Farmers surround the fields with hedgerows during high insolation period to:

prevent the reduction in photosynthetic activity.

reduce evapotranspiration.

create conditions for plants to close their stomata.

prevent wilting of plants.

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UPSC Geoscientist – 2020

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Farmers surround fields with hedgerows during high insolation periods (which often coincide with hot, dry, and potentially windy conditions) primarily to reduce evapotranspiration. Hedgerows act as windbreaks, lowering wind speed over the field, which in turn reduces both evaporation from the soil surface and transpiration from the plants.

– Evapotranspiration is the combined loss of water from the soil surface by evaporation and from plants by transpiration.
– High wind speed increases the rate of both evaporation and transpiration.
– By reducing wind speed, hedgerows decrease the rate of water loss from the field, helping to conserve soil moisture and reduce plant water stress.

– Reducing evapotranspiration is particularly important during periods of high insolation and temperature when water demand is high.
– While reducing water stress can indirectly help prevent wilting and support photosynthesis, the direct mechanism addressed by reduced wind speed is the reduction of water loss through evapotranspiration.
– Hedgerows also provide habitat for wildlife and can help prevent soil erosion.

25. Bog ecosystem wetland receives water only from:

Bog ecosystem wetland receives water only from:

Rain

Streams

Rivers

Groundwater

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Bog wetlands are characterized by receiving water and nutrients primarily, and often exclusively, from precipitation (rain). This makes them ombrotrophic ecosystems, meaning they are rain-fed and their chemistry is dictated by atmospheric inputs rather than groundwater or surface water.

– Bogs are typically acidic and nutrient-poor because rain is naturally acidic and low in nutrients compared to groundwater or surface water.
– They are dominated by Sphagnum moss, which contributes to the acidic conditions and peat formation.
– Unlike fens, marshes, or swamps, bogs are typically isolated from mineral-rich groundwater and surface water flow.

– Other types of wetlands like fens receive water from groundwater (minerotrophic), which results in less acidic and more nutrient-rich conditions.
– Swamps and marshes are often fed by surface water runoff or groundwater and can be dominated by trees, shrubs, or grasses.
– The hydrological source is a key factor distinguishing different types of wetlands.

26. Pneumatophores are specialized structures for:

Pneumatophores are specialized structures for:

maintaining turgor pressure in cells.

providing physical support to plants in marshy lands.

oxygen inhalation by plants.

carbon dioxide release during photosynthesis.

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Pneumatophores are specialized root structures that grow upwards from the soil in plants found in waterlogged or anaerobic conditions, such as mangrove swamps. Their primary function is to facilitate the diffusion of oxygen into the root system, essentially acting for oxygen inhalation by the plant roots in oxygen-poor soil.

– Pneumatophores are negative geotropic roots, growing vertically upwards out of the mud or water.
– They possess pores (lenticels) on their surface that allow for gas exchange.
– They contain spongy tissue (aerenchyma) that stores and transports air to the submerged roots.

– Examples of plants with pneumatophores include various mangrove species (like *Avicennia* and *Sonneratia*) and some other wetland plants.
– They are an adaptation to anaerobic conditions where oxygen is scarce in the soil due to waterlogging.
– Other specialized root structures in mangroves include prop roots and buttress roots, which provide physical support, but pneumatophores are specifically for gas exchange.

27. The biological oxygen demand (BOD) of unpolluted river water is:

The biological oxygen demand (BOD) of unpolluted river water is:

10 - 20 mg O₂/dm³/5 day.

5-10 mg O₂/dm³/5 day.

less than 5 mg O₂/dm³/5 day.

more than 20 mg O₂/dm³/5 day.

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UPSC Geoscientist – 2020

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The biological oxygen demand (BOD) is a measure of the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material present in a water sample. Unpolluted river water contains very little organic matter and thus requires very little oxygen for decomposition, resulting in a low BOD value, typically less than 5 mg O₂/dm³/5 day.

– BOD is a key indicator of water quality, reflecting the amount of biodegradable organic pollution.
– It is measured over a specific period, usually 5 days (BOD₅) at a standard temperature (20°C).
– Lower BOD values indicate better water quality with less organic pollution.

– Very clean water typically has a BOD of 1-2 mg/L.
– Moderately polluted water might have BOD values between 2 and 8 mg/L.
– Heavily polluted water can have BOD values exceeding 20 mg/L.
– The term dm³ is equivalent to a liter (1 dm³ = 1 L).

28. Thermal pollution which involves release of excessive amounts of heate

Thermal pollution which involves release of excessive amounts of heated water in aquatic systems is harmful. It is because hot water:

kills aquatic plants.

causes oxygen starvation.

kills aquatic microbes.

causes CO₂ depletion.

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The release of excessive heated water into aquatic systems causes thermal pollution, which is harmful because hot water holds less dissolved oxygen compared to cold water, leading to oxygen starvation for aquatic organisms.

– Solubility of gases in water decreases as temperature increases. Therefore, less oxygen can dissolve in hot water.
– Higher water temperatures increase the metabolic rates of fish and other aquatic organisms, which increases their demand for oxygen.
– The combined effect of reduced oxygen availability and increased oxygen demand can lead to stress, suffocation, and death of aquatic life.

– Thermal pollution can also affect the reproduction, growth, and behavior of aquatic species.
– It can alter species composition, favoring tolerant species and eliminating sensitive ones.
– Sources of thermal pollution often include cooling water discharges from power plants, industrial facilities, and urban runoff.

29. The broad estimates of sea level rise due to global warming by 2100 is

The broad estimates of sea level rise due to global warming by 2100 is approximately:

10 cm

20 cm

30 cm

40 cm

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Broad estimates of global mean sea level rise by the year 2100 due to global warming vary depending on emission scenarios and models. While projections range from about 30 cm to over 1 meter, 40 cm falls within the plausible range often cited as a lower-to-mid estimate in various assessments or as a rounded figure representative of a significant, yet not extreme, rise within the century.

– Sea level rise is caused primarily by the thermal expansion of seawater and the melting of glaciers and ice sheets.
– Projections for sea level rise are based on climate models and future greenhouse gas emission scenarios.
– The Intergovernmental Panel on Climate Change (IPCC) reports provide detailed projections with associated uncertainty ranges for different scenarios.

– The IPCC AR6 report (2021) projects a *likely* global mean sea level rise by 2100 (relative to 1995–2014) of 28–55 cm under a very low emissions scenario (SSP1-1.9) and 63–101 cm under a very high emissions scenario (SSP5-8.5).
– The options provided (10, 20, 30, 40 cm) are relatively low compared to the midpoints of even the lowest IPCC ranges, but 40 cm is the highest option and falls within the lower part of the range projected under moderate emission scenarios by earlier reports or as a rounded figure. Given the options, 40 cm is the most reasonable “broad estimate” among the choices.

30. Which of the following particulate matters (size based) are notified p

Which of the following particulate matters (size based) are notified pollutants in National Ambient Air Quality Standards (NAAQS)?

PM 10 and PM 3.5

PM 9 and PM 2.5

PM 10 and PM 2.5

PM 5 and PM 3.5

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India’s National Ambient Air Quality Standards (NAAQS), as revised in 2009, include standards for particulate matter based on size, specifically PM 10 and PM 2.5.

– Particulate matter is a mixture of solid particles and liquid droplets found in the air.
– PM10 refers to particles with a diameter of 10 micrometers or less.
– PM2.5 refers to fine particles with a diameter of 2.5 micrometers or less.
– Both PM10 and PM2.5 are regulated under NAAQS due to their significant health impacts.

– The NAAQS specify concentration limits for PM10 and PM2.5 over different averaging periods (e.g., 24-hour and annual mean).
– Other pollutants listed in NAAQS include Sulphur Dioxide (SO₂), Nitrogen Dioxide (NO₂), Carbon Monoxide (CO), Ozone (O₃), Lead (Pb), Ammonia (NH₃), Benzene (C₆H₆), Benzo(a)Pyrene (BaP), Arsenic (As), and Nickel (Ni).