Geography: UPSC Previous Year Questions (Prelims)

Explanation

Statement 1 is correct: About 97.5% of Earth’s water is saltwater found in oceans. The remaining 2.5% is freshwater. Most of it is locked in glaciers, ice caps, or deep underground. Only about 0.3% of total freshwater is readily available in rivers, lakes, and accessible groundwater for human use. Since 0.3% of 2.5% is less than 1% of total water, this confirms that freshwater available for use is indeed less than 1%.

Statement 2 is incorrect: Around 68.7% of all freshwater is stored in ice caps and glaciers, primarily in the Antarctic and Greenland ice sheets. The remaining freshwater is found in groundwater, rivers, and lakes. The volume of water in rivers and lakes combined is only about 0.3% of the total freshwater available.

Explanation

Tropical rainforests, also known as Evergreen forests, thrive in regions receiving substantial rainfall, typically exceeding 150-200 cm annually. These forests maintain temperatures within the range of 15-30°C throughout the year, conditions that match the given data. They are found in India’s Western Ghats and Northeast, boasting diverse flora (rosewood, mahogany, rubber) and fauna (elephants, monkeys, sloths). This combination of factors creates a complex and thriving ecosystem.

Explanation

El Niño is a climate pattern characterized by unusually warm ocean temperatures in the eastern equatorial Pacific Ocean. El Niño Modoki is a distinct phase of El Niño with a different spatial pattern of warming in the Pacific Ocean.

Statement 1 is incorrect: Because it reverses the typical locations of El Niño and El Niño Modoki. Normal El Niño occurs in the Eastern Pacific Ocean, where sea surface temperatures be-come unusually warm, typically around the equator off the coast of South America. El Niño Modoki, on the other hand, forms in the Central Pacific Ocean, with warming concentrated between the dateline and the central Pacific, distinct from the usual location of normal El Niño.

Statement 2 is correct: During normal El Niño events, the atmospheric changes (increased wind shear and cooler waters in the Atlantic) tend to suppress hurricane formation in the Atlantic Ocean, leading to fewer hurricanes. In contrast, El Niño Modoki causes different atmospheric conditions that have been linked to a greater frequency and intensity of hurricanes in the Atlantic Ocean. The shift in warming in the Pacific Ocean results in a different pattern of atmospheric circulation that enhances hurricane formation in the Atlantic.

Explanation

The reflectivity of a surface, known as albedo, determines how much sunlight is reflected back. Surfaces with higher albedo reflect more sunlight, while those with lower albedo absorb more.

Option (c) is correct: Land covered with fresh snow has the highest albedo amongst the options given above. Snow reflects approximately 80-90% of the sunlight that strikes it. This makes snow-covered surfaces highly reflective compared to others. Options (a), (b) and (d) are incorrect:

Sand deserts have a lower albedo, generally ranging between 30-40%. This means they absorb more sunlight and reflect less compared to snow-covered land. Paddy crop land, similar to prairie land, has a lower albedo of 22-24% due to its vegetation, which absorbs more sunlight rather than reflecting it. The albedo of these areas can change based on vegetation type, moisture levels, and the season. Prairie land, like paddy crop land, typically has a lower albedo of 20-25 % as it is covered with grasses and other vegetation that absorb sunlight rather than reflecting it.

Explanation

Option (a) is correct: The Mediterranean region is characterized by a warm and dry climate with mild, wet winters and is home to evergreen oak trees. The region, including parts of Southern Europe, Northern Africa, and Western Asia (e.g., Spain, Italy, Greece, and Turkey), aligns with these climatic and vegetative features, making it distinct compared to other areas. The Mediterranean climate is marked by hot, dry summers and mild, rainy winters, supporting this unique vegetation. Options (b), (c) and (d) are incorrect:

Eastern China, including the Yangtze River Basin and Shanghai, has a humid subtropical climate with hot, humid summers and cold winters. It features deciduous forests and bamboo groves, with year-round rainfall, unlike the warm, dry Mediterranean climate with evergreen oaks. Central Asia, covering countries like Kazakhstan, Uzbekistan, and Turkmenistan, has a continental climate with hot summers and very cold winters. The region is dominated by grasslands (steppes) and desert vegetation, with minimal tree cover, and lacks the evergreen oak trees and mild, wet winters associated with Mediterranean climates. The Atlantic coast of North America, stretching from the Southeastern United States to the Mid-Atlantic states, features a humid subtropical climate with hot summers and mild to cool winters. Vegetation includes pine forests, deciduous trees, and wetlands, but it does not exhibit the evergreen oak trees or the warm, dry climate typical of Mediterranean regions.

Explanation

The Coriolis force, which is caused by the Earth’s rotation, is responsible for the deflection of wind patterns. This force influences moving objects, such as winds, and causes them to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. The Coriolis effect is strongest at the poles and diminishes towards the equator. In the Southern Hemisphere, the wind is deflected to the left due to the Earth’s rotation, which results in the clockwise movement of cyclones and alters global wind patterns like trade winds, westerlies, and polar easterlies.

Explanation

Tamil Nadu is a leading producer of mill-made cotton yarn in India due to the availability of a rich pool of skilled labor, which is crucial for operating the state’s large textile industry. The state has a long tradition of textile manufacturing, supported by well-developed infrastructure and favorable government policies.

Statement 1 is incorrect: Black cotton soil is often considered ideal for cultivating cotton because of its moisture-retaining properties. However, this soil type is not predominant in Tamil Nadu. Instead, black cotton soil is commonly found in states like Maharashtra, Gujarat, and Madhya Pradesh. The cotton used in Tamil Nadu’s mills is primarily sourced from these cotton-growing regions, rather than being grown locally on black cotton soil.

Statement 2 is correct: Tamil Nadu has a long-established tradition in textile manufacturing. The state is renowned for its skilled and semi-skilled workers who efficiently manage complex mill operations, machinery, and quality control. This expertise is one of the major reasons behind its leading position in the cotton yarn industry.

Explanation

Statement 1 is correct: Coffee plant requires a hot and humid climate of tropical areas whereas tea can be cultivated in both tropical and subtropical areas. Coffee thrives in a hot and humid tropical climate, requiring temperatures between 15°C and 28°C with well-distributed rainfall. Traditional coffee producing regions include the southern states of Karnataka (largest producer), Kerala, and Tamil Nadu. Non-traditional regions consist of Andhra Pradesh and Odisha, located in the Eastern Ghats of India. Tea can grow in both tropical and subtropical with temperaturerange 20-30°C requiring high humidity and well-distributed rainfall (100-200 cm) areas. For example, it is cultivated in Assam (tropical) and Darjeeling (subtropical) regions. Assam is the largest producer of tea in the country.

Statement 2 is incorrect: Coffee is propagated by seeds but tea is not propagated by stem cuttings only. Coffee is primarily propagated by seeds, but vegetative propagation methods like cuttings and grafting are also used. Tea is propagated both by seeds and vegetative methods, including stem cuttings and grafting, depending on the desired plant characteristics. In tea cultivation, cuttings are planted either upright or at a slight angle, ensuring that the leaves do not come into contact with the soil. After developing roots, they are transferred to the field approximately 12 months later. Seeds, on the other hand, are sown at a depth of 1.5 to 2.5 cm.

Explanation

Soil conservation techniques aim to prevent soil erosion, improve soil fertility, and maintain ecological balance.

Option 1 is correct: Rotating crops helps maintain soil fertility by alternating nutrient-exhausting crops with nitrogen-fixing ones, reducing soil degradation and pest infestations. Legumes are rotated with cereals to fix nitrogen in the soil in states like Punjab and Haryana.

Option 2 is correct: Sand fences are barriers made of wood or other materials to trap sand and stabilize soil in areas prone to wind erosion, such as coastal or desert regions. It is practised in arid regions like Rajasthan, where wind erosion is a problem.

Option 3 is correct: Terracing involves creating step-like structures on slopes, which slows down water runoff, prevents soil erosion, and conserves moisture, making it highly effective in hilly areas.

Option 4 is correct: Wind breaks are rows of trees or shrubs planted to reduce wind speed and protect soil from erosion, especially in open fields. It is commonly used in hilly regions like the Himalayas and Western Ghats.

Explanation

The National Development Council (NDC) in 2007 adopted a resolution to launch a Food Security Mission comprising rice, wheat and pulses to increase the annual production of rice by 10 million tonnes, wheat by 8 million tonnes and pulses by 2 million tonnes by the end of the Eleventh Plan (2011-12). Accordingly, a Centrally Sponsored Scheme, ‘National Food Security Mission’ (NFSM), was launched in October 2007. Initially, NFSM (2007-08) focused on rice, wheat, and pulses only. The objectives of NFSM are:

Increase production of specific crops through area expansion and productivity enhancement. Ensure sustainability by focusing on improved technologies and efficient resource use. Enhance farm profitability and rural livelihoods.