Daily Quiz: UPSC Prelims Marathon (Geography) – July 10, 2020

According to the scientists, including those from NASA’s Jet Propulsion Laboratory in the US, a sea-water current called the Beaufort Gyre keeps the polar environment in balance by storing fresh water near the surface of the Arctic Ocean.

• Wind blows the gyre in a clockwise direction around the western Arctic Ocean, north of Canada, where it naturally collects fresh water from the melting of glaciers, and river runoff.
• The researchers said this fresh water is important in the Arctic since it floats above the warmer, salty water, and helps protect the sea ice from melting – in turn regulating the Earth’s climate.
• As the fresh water is slowly released by the gyre into the Atlantic Ocean over a period of decades, it allows the Atlantic Ocean currents to carry it away in small amounts.
• However, since the 1990s, the researchers said, the gyre has accumulated a large amount of fresh water – 8,000 cubic kilometres – or almost twice the volume of Lake Michigan in the US.
• According to the new study, the cause of this gain in freshwater concentration is the loss of sea ice in summer and autumn.
• Due to this decades-long decline of the Arctic’s summertime ice cover, the Beaufort Gyre is more exposed to the wind, which has spun the gyre faster, trapping the fresh water in its current.

The Atlantic Meridional Overturning Circulation (AMOC) is a large system of ocean currents that carry warm water from the tropics northwards into the North Atlantic.

• The AMOC is a large system of ocean currents, like a conveyor belt, driven by differences in temperature and salt content – the water’s density.
• As warm water flows northwards it cools and some evaporation occurs, which increases the amount of salt.
• Low temperature and a high salt content make the water denser, and this dense water sinks deep into the ocean.
• The cold, dense water slowly spreads southwards, several kilometres below the surface (As that water cools and sinks it drives a slow circulation of the oceans that is critical to global climate, affecting the location of droughts and frequency of hurricanes).
• Eventually, it gets pulled back to the surface and warms in a process called “upwelling” and the circulation is complete.
• This global process makes sure that the world’s oceans are continually mixed, and that heat and energy are distributed around the earth. This, in turn, contributes to the climate we experience today.
• As that water cools and sinks it drives a slow circulation of the oceans that is critical to global climate, affecting the location of droughts and frequency of hurricanes.
• It also stores heat-trapping carbon dioxide deep in the ocean.

THE KUROSHIO IS a warm northeasterly ocean current off the coast of Japan. This current is also called the gulf stream of the Pacific or Japan Current.

• Kuroshio means “the black stream” in Japanese, named after the deep ultramarine color of the high salinity water, which is found flowing north of the current’s axis.
• The system includes the following branches: Kuroshio, up to 35 degrees N; Kuroshio extension, extending eastward into two branches up to 160 degrees E longitude;
• North Pacific current, a further eastward continuation, which throws branches to the south as far as 150 degrees W;
• Tsushima current, branches of the main current that run into the Japan Sea, along the west coast of JAPAN;
• And Kuroshio counter-current, the large swirl or eddy on the east and south east of the Kuroshio.

The German icebreaker RV Polarstern, a hulking ship will set out for the Arctic packed with supplies and scientific equipment for a year-long mission to explore the planet’s frigid far north.

• The icebreaker will be the base for scientists from 17 nations studying the impact of climate change on the Arctic and how it could affect the rest of the world.
• Spearheaded by the Alfred Wegener Institute in Germany, MOSAiC (multidisciplinary drifting observatory for the Study of Arctic Climate expedition), the largest ever Arctic expedition in history, will be the first to conduct a study of this scale at the North Pole for an entire year.

Latosols are soils found under tropical rainforests which have a relatively high content of iron and aluminum oxides. They are typically classified as oxisols or ferralsols.

Demographic transition theory can be used to describe and predict the future population of any area.

• The theory tells us that population of any region changes from high births and high deaths to low births and low deaths as society progresses from rural agrarian and illiterate to urban industrial and literate society. These changes occur in stages which are collectively known as the demographic cycle.
• The first stage has high fertility and high mortality because people reproduce more to compensate for the deaths due to epidemics and variable food supply.
• Fertility remains high in the beginning of second stage but it declines with time. This is accompanied by reduced mortality rate. Improvements in sanitation and health conditions lead to decline in mortality. Because of this gap the net addition to population is high.

In the last stage, both fertility and mortality decline considerably. The population is either stable or grows slowly. The population becomes urbanized, literate and has high technical knowhow and deliberately controls the family size.

There is a clear demographic divergence between north-central and south-western regions; one is a young hinterland with vast labour force and the other ones are ageing with decreasing working age population.

• Most of the current and future demographic potential is locked in the north-central States, and largely located in Bihar, Jharkhand, Madhya Pradesh, Rajasthan, and Uttar Pradesh.
• As per population projections by UNFPA, these five States will account for more than half of the growth in the labour force in India.
• Those who are under 15 years of age today will become India’s working population in coming decades. Almost every second person in this age group resides in these five States.
• The accompanying figure shows that there is a gap of almost 20 years between the northern hinterland and southern States in terms of the peak of the working age ratios in these regions.

There are many ways of looking at the problem of human development. Some of the important approaches are: (a) The income approach; (b) The welfare approach; (c) Minimum needs approach; and (d) Capabilities approach.

The regions where farmers specialise in vegetables only, the farming is known as truck farming. The distance of truck farms from the market is governed by the distance that a truck can cover overnight, hence the name truck farming.

A pack animal is a type of animal used by humans to carry heavy loads. These animals carry goods and supplies upon their backs across long distances or difficult terrain.

• They are not to be confused with draft animals, which pull weight on a cart or sled. The use of animals to carry cargo dates as far back as 3500 BC.
• Historical evidence suggests that donkeys have served as pack animals for longer than any other species. Other types of common pack animals include camels, yaks, horses, llamas, oxen, and water buffalos.
• Horses are used as a draught animal even in the Western countries.
• Dogs and reindeer are used in North America, North Europe and Siberia to draw sledges over snow-covered ground.
• Mules are preferred in the mountainous regions; while camels are used for caravan movement in deserts. In India, bullocks are used for pulling carts.