Daily Quiz: UPSC Prelims Marathon (Geography) – August 21, 2020

Lucky latitudes are refers to the geographical regions where the practice of domestication of wild plants and animals began to happen for the first time in human history.

• It includes land that lies between the latitudes of 20 and 35 degrees north in the Old World, and 15 degrees south and 20 degrees north in the Americas.
• These regions became more favourable to the rise of civilization when the rise in earth’s temperature ended the last Ice Age around 12,000 years ago.
• Consequently, people located in these geographic regions gained a head-start over the rest of the world.
• The term was coined by Ian Morris in his book Why the West Rules — For Now.

Studying debris-laden Himalayan glaciers is important from the point of view of how climate change affects them.

• About 20% of Himalayan glaciers are debris-laden, and their dynamics are very different from the ones without debris cover. 
• In glaciers without a debris cover, the rate of melting increases as the elevation decreases.
• However, in glaciers covered with debris, the thick cover partially insulates the glacier from the warm exterior and thereby slows down the melting.
• The thickness of the debris cover, by and large, increases as the glacier flows down.
• This works against the general trend that the lower the elevation, the higher the rate of melting.
• Matters are further complicated because the thickness of the debris cover is not uniform but fluctuates randomly.

Dozens of people will undertake a “funeral march” up a steep Swiss mountainside on September 2019, to mark the disappearance of an Alpine glacier amid growing global alarm over climate change.

• Dressed in black, they will make the solemn two-hour “funeral march” up the side of Pizol mountain in northeastern Switzerland to the foot of the steep and rapidly melting ice formation, situated at an altitude of around 2,700 metres (8,850 feet) near the Liechtenstein and Austrian borders
• The move comes after Iceland made global headlines last month with a large ceremony and the laying of a bronze plaque to commemorate Okjokull, the island’s first glacier lost to climate change.
• The researchers indicated that the Alps’ largest glacier, the mighty Aletsch, could completely disappear over the next eight decades.

Two-thirds of Himalayan glaciers, the world’s “Third Pole”, could melt by 2100 if global emissions are not reduced, scientists warned in a major new study issued in 2019.

• And even if the “most ambitious” Paris Agreement goal of limiting global warming to 1.5° C is achieved, one-third of the glaciers would go, according to the Hindu Kush Himalaya Assessment.
• Glaciers in the Hindu Kush-Himalaya (HKH) region are a critical water source for some 250 million people in the mountains as well as to 1.65 billion others in the river valleys below, the report said.
• The glaciers feed 10 of the world’s most important river systems, including the Indus, Ganges, Brahmaputra, Irrawaddy, Salween, Mekong, Yangtze, Yellow, Amu Darya and Tarim.
• And directly or indirectly supply billions of people with food, energy, clean air and income.

In the course of a year, the earth’s revolution round the sun with its axis inclined at 66 ½ to the plane of the ecliptic changes the apparent altitude of the midday sun.

• The sun is vertically overhead at the equator on two days each year. These are usually 21^st march and 21^st
• After the March equinox the sun appears at move north and is vertically overhead at the tropic of cancer on about 21^st
• By about 22^nd December, the sun will be overhead at the tropic of Capricorn.

The tropics thus mark the limits of the overhead sun, for beyond these, the sun is never overhead at any time of the year.

Igneous rocks may be subdivided on the basis of mineral composition.

• When they contain a high proportion of silica they are said to be acid.
• Acid igneous rocks, such as granite, are less dense and are lighter in colour than basic rocks.
• These contain a greater proportion of basic oxides, e.g. of iron, aluminum or magnesium, and are thus denser and darker in colour.

Stevenson screen: A Stevenson screen (also known as an instrument shelter) is a meteorological screen to shield instruments against precipitation and direct heat radiation from outside sources, while still allowing air to circulate freely around them.

It forms part of a standard weather station.

Beaufort scale: The Beaufort Scale is an empirical measure that relates wind speed to observed conditions at sea or on land. Its full name is the Beaufort wind force scale.

Hygrometer: Hygrometer, instrument used in meteorological science to measure the humidity, or amount of water vapour in the air.

The effects of climate change are at our doorsteps.

• Cyclones such as Thane, Vardah, Ockhi and Gaja have affected Tamil Nadu in recent times;
• Chennai saw terrible floods in 2015.
• Floods wreaked havoc in Assam, Himachal Pradesh and Bihar this year, and Mumbai received record monsoon rains.
• Kerala witnessed floods for the second consecutive year.
• Cyclone Fani devastated Odisha, Cyclone Vayu ravaged Gujarat this year. All these are because of climate change.

Namib Desert: the Namib Desert is a direct result of the Benguela Current.

• Seamounts near to the coastline beneath the Atlantic’s surface cause the icy Benguela River to flow very close to the Namibian coast.
• This causes a harsh coastal climate with very little rainfall.

Atacama Desert: Cold ocean currents contribute to the formation of coastal deserts.

• Air blowing toward shore, chilled by contact with cold water, produces a layer of fog. This heavy fog drifts onto land.
• The Atacama Desert, on the Pacific shores of Chile, is a coastal desert.
• Some areas of the Atacama are often covered by fog. But the region can go decades without rainfall. In fact, the Atacama Desert is the driest place on Earth.

Gobi Desert: Interior deserts, which are found in the heart of continents, exist because no moisture-laden winds reach them.

• By the time air masses from coastal areas reach the interior, they have lost all their moisture. Interior deserts are sometimes called inland deserts.
• The Gobi Desert, in China and Mongolia, lays hundreds of kilometers from the ocean. Winds that reach the Gobi have long since lost their moisture.
• The Gobi is also in the rain shadow of the Himalaya Mountains to the south.

Chaparral is sclerophyllous vegetation that is tolerant of seasonal drought.

• It consists of small trees, woody grasses and oleose, xerophytic shrubs that form a nearly continuous cover of intertwined branches.
• Usually less than 10 per cent of the ground is bare, though the proportion may be higher at inhospitable sites.
• Where annual precipitation is in the range 250–500 mm, plants may be only 1–2 m high, while crowns may reach 3.5–4 m where precipitation is 500–750 mm.
• In California chaparral is common at elevations of 300–1500 m. It occupies 3.4 million ha (8.5 per cent) of the state, particularly in its southern part and at moderate elevations.

The European synonym for chaparral, maquis (in Italian, macchia, plural macchie), is derived from the Corsican word for a species of sun rose (Cistus), which is often a striking component of the maquis community.