WHAT ARE POLES OF INACCESSIBLILITY?

Every continent has a point hardest to reach from the coast of a landmass, either due to tough terrain or untraversable routes, or sheer distance from the coast. A pole of inaccessibility (not to be confused with the North and South Poles), is the point on any continent that is hardest to reach from the coast. There is one on every continent and a couple in the middle of the ocean! The Arctic pole of inaccessibility is a few hundred kilometres from the North Pole. Since there is no landmass so far north, the pole is calculated as the northernmost point that is furthest from land. Like the North Pole, it is located on the shifting pack ice of the northern Arctic Sea. The spot in Eurasia that is furthest from the ocean is located north of Ürümqi in northwest China, over 2,400km from the coast in the middle of desert. Both the North American an South American poles as well as the African pole are located near small towns. Two are in the midst of dense jungle and all three are over 1,760km from the nearest coast.  Australian's remotest point is only 900 km from the nearest coast, in the northern Territory.

The Southern pole of inaccessibility (750 km from the South Pole) has a Russian research station built there in 1958. Also known as the Oceanic pole of inaccessibility, Point Nemo, in the South Pacific Ocean, is over 1,400 nautical miles from the three closest islands.

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Which is the highest volcano?

Nevado Ojos del Salado is the highest volcano on Earth and the highest peak in Chile. It is a dormant complex volcano in the Andes on the Argentina-Chile border. It stretches for about 70-160 square kilometres and its highest summit reaches an altitude of 6,893 metres above sea level. It is part of the Nevado de Tres Cruces National Park, which is situated 290 kilometres from the town of Copiapo of the Chilean Atacama region and 600 kilometres from Mount Aconcagua, which is the highest mountain in the Western Hemisphere.

The climate of this mountain region is rather dry due to its proximity to the Atacama Desert that is situated to the west of the Andes Mountain. Ojos Del Salado is a popular hiking destination because of its easy trail, except the last stretch before the summit, which requires equipment to climb. Jan Alfred Szczepanski and Justyn Wojsznis were the first to reach the top of Ojos Del Salado in 1937.

There are no confirmed eruptions of Ojos del Salado. In 1993, there were reports of a minor gas-and-ash emission, but this could not be confirmed.

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What are the specialities of the Tibetan Plateau?

Owing to its elevation, the Tibetan Plateau is known as the Roof of the World (Bam-i- Duniah). This region of Asia is known as High Asia, with an average elevation of 4511 metres above sea level, making the Tibetan Plateau the world's highest plateau.

It was formed and is still being formed due to the collision of the Indo-Australian and Eurasian tectonic plates- these plates started colliding about 70 million years ago! The Tibetan Plateau has a number of saline and freshwater glacial lakes, that is, there are about 1,500 large and small lakes with a total area of 24,183 square kilometres as on 2008.

It is also called the Third Pole due to its ice fields, which are the world's greatest freshwater resource other than the Polar Regions. This region gives rise to some of the most important rivers of Asia including the Brahmaputra, Indus, Ganges, Salween, Mekong, Yangtze, and Yellow river.

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What are the specialities of the Great Barrier Reef?

The Great Barrier Reef covers an area of 348,000 square kilometres, and is the longest and largest reef complex of the planet. In fact, this remarkable site is one of the seven wonders of the natural world. Located on the north-east coast of Australia, the Great Barrier Reef is home to a huge diversity of species and habitats. This ecosystem is intricately interconnected, making it one of the richest and most complex natural ecosystems on earth.

It is home to over 1,500 species of fish, 400 species of corals, and 4,000 species of molluscs. It also hosts 240 species of birds along with a number of sponges, anemones, marine worms, crustaceans, and other species. This giant marvel is also home to many endemic and threatened species listed by the International Union for Conservation of Nature (IUCN). These features make it a very popular tourist destination and thus contribute to the economic development of the country.

In order to safeguard and preserve the reef, it was declared as the Great Barrier Reef Marine Park in 1975, and the supervision of the park was handed over to the authorities of the Marine Park.

Owing to its significance in the ocean ecosystem, the Great Barrier Reef was added to UNESCO’s World Heritage List.

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WHAT ARE ICEBERGS AND WHY ARE THEY DANGEROUS?

Icebergs are huge pieces of ice that break off glaciers and float into the ocean. They can be more than five metres in height but most of their bulk remains submerged. Icebergs are dangerous. If a ship hits an iceberg, it can be badly damaged and sink. The dangerous waters are in the North Atlantic, around Greenland, and in the Southern Hemisphere around Antarctica. Since I912, after the luxury liner Titanic hit an iceberg and sank, the International Ice Patrol tracks icebergs and warns ships in the North Atlantic. However, satellite data used to monitor icebergs can only spot icebergs larger than 500 m2.

Icebergs are large chunks of ice that break off from glaciers. This process is called calving. Icebergs float in the ocean, but are made of frozen freshwater, not saltwater.

Most icebergs in the Northern Hemisphere break off from glaciers in Greenland. Sometimes they drift south with currents into the North Atlantic Ocean. Icebergs also calve from glaciers in Alaska.

In the Southern Hemisphere, almost all icebergs calve from the continent of Antarctica.

Some icebergs are small. Bergy bits are floating sea ice that stretch no more than 5 meters (16.5 feet) above the ocean. Growlers are even smaller.

Icebergs can also be huge. Some icebergs near Antarctica can be as big as Sicily, the largest island in the Mediterranean Sea. As little as one-eighth of an iceberg is visible above the water. Most of the mass of an iceberg lies below the surface of the water. This is where the phrase "tip of the iceberg" came from, meaning only part of an idea or problem is known.

There are many different kinds of icebergs. Brash ice, for instance, is a collection of floating ice and icebergs no more than 2 meters (6.5 feet) across. A tabular berg is a flat-topped iceberg that usually forms as ice breaks directly off an ice sheet or ice shelf.

The ice below the water is dangerous to ships. The sharp, hidden ice can easily tear a hole in the bottom of a ship. A particularly treacherous part of the North Atlantic has come to be known as Iceberg Alley because of the high number of icebergs that find their way there. Iceberg Alley is located 250 miles east and southeast of Newfoundland, Canada.

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DOES ANYONE LIVE AT THE NORTH POLE?

Drifting ice makes it very difficult to create settlements at the North Pole. It is an uninhabited area that does not belong to any nation. But it does have research stations based there to study the region and look for changes in the ecosystem.

No one really resides at the true North Pole, not even the Inuit people who dwell in the nearby Arctic regions of Greenland, Russia, Canada, etc. It’s almost impossible to build a permanent home here, as the ice is in constant motion and shrinks significantly in summers. Thus, it is not viable to build permanent structures or establish any sort of community there. Another challenge of establishing a community at the true North Pole is that there is no availability of potable water. Even the adventurous explorers who come to the North Pole just for a short trip must ensure that there is a sufficient supply of water available to them. Early Arctic explorers had a very hard time keeping themselves hydrated here. The water of the nearby Arctic is too salty to meet day-to-day consumption requirements. In extreme cases, people survived by eating snow. Eating snow isn’t a good thing either and increases the risk of hypothermia, a condition in which the body loses heat rapidly, plunging to alarming or fatal levels.

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WHAT IS IT LIKE AROUND THE NORTH POLE?

In geographical terms, the North Pole is the northernmost point on Earth’s axis of rotation. It is located in the Arctic, on the drifting, two to three metres thick ice that covers the waters of the ocean here. The warmest the North Pole gets is 0°C. Usually, though, the temperature is a bitterly cold sub-zero. In summer, the North Pole is bathed in the constant daylight, but the winter is a long, continuous dark night.

The North Pole is the northernmost point on Earth. It is the precise point of the intersection of the Earth's axis and the Earth's surface.

From the North Pole, all directions are south. Its latitude is 90 degrees north, and all lines of longitude meet there (as well as at the South Pole, on the opposite end of the Earth). Polaris, the current North Star, sits almost motionless in the sky above the pole, making it an excellent fixed point to use in celestial navigation in the Northern Hemisphere.

The North Pole sits in the middle of the Arctic Ocean, on water that is almost always covered with ice. The ice is about 2-3 meters (6-10 feet) thick. The depth of the ocean at the North Pole is more than 4,000 meters (13,123 feet).

The Canadian territory of Nunavut lies closest to the North Pole. Greenland, the world's largest island and an independent country within the Kingdom of Denmark, is also close to the pole.

The North Pole is much warmer than the South Pole. This is because sits at a lower elevation (sea level) and is located in the middle of an ocean, which is warmer than the ice-covered continent of Antarctica. But it's not exactly beach weather. In the summer, the warmest time of year, the temperature is right at the freezing point: 0 degrees Celsius (32 degrees Fahrenheit.)

Because the Earth rotates on a tilted axis as it revolves around the sun, sunlight is experienced in extremes at the poles. In fact, the North Pole experiences only one sunrise (at the March equinox) and one sunset (at the September equinox) every year. From the North Pole, the sun is always above the horizon in the summer and below the horizon in the winter. This means the region experiences up to 24 hours of sunlight in the summer and 24 hours of darkness in the winter.

Credit: National Geographic

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HAVE THERE BEEN MANY ICE AGES?

There have been at least five major ice ages in Earth’s history: the Huronian,  Cryogenian, Andean-Saharan, late Palaeozoic and Quaternary. The study of rocks dates the Huronian around 2.1 billion years ago. The Cryogenic, around 700 million   years ago may have seen Earth almost totally frozen, like a snowball. The Andean-Saharan Ice Age happened around 400 million years ago. The late Palaeozoic, around 360 million years ago, had extensive polar ice caps. The Quaternary Age began around

2.5 million years ago. At present, Earth is in an interglacial period it is between ice ages.

There have been five or six major ice ages in the history of Earth over the past 3 billion years. The Late Cenozoic Ice Age began 34 million years ago, its latest phase being the Quaternary glaciation, in progress since 2.58 million years ago.

Within ice ages, there exist periods of more severe glacial conditions and more temperate conditions, referred to as glacial periods and interglacial periods, respectively. The Earth is currently in such an interglacial period of the Quaternary glaciation, with the last glacial period of the Quaternary having ended approximately 11,700 years ago. The current interglacial is known as the Holocene epoch. Based on climate proxies, paleoclimatologists study the different climate states originating from glaciation.       

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WHAT BRINGS ABOUT THE END OF AN ICE AGE?

The rotation and revolution of Earth, the amount of solar radiation and the amount of carbon dioxide in the atmosphere are all factors that contribute to a warming up of Earth, which ends an ice age. Changes in ocean currents also have a major effect on temperatures on Earth.

Over thousands of years, the amount of sunshine reaching Earth changes by quite a lot, particularly in the northern latitudes, the area near and around the North Pole. When less sunlight reaches the northern latitudes, temperatures drop and more water freezes into ice, starting an ice age. When more sunlight reaches the northern latitudes, temperatures rise, ice sheets melt, and the ice age ends.

Credit: American Museum of Natural History

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WHAT ARE THE LARGEST BODIES OF ICE IN THE WORLD?

In today’s world, the ice sheets of Antarctica and Greenland. An ice sheet is a continuous mass of ice covering more than 50,000 km2. The ice sheet in Antarctica covers 14 million km2. It is 1.6 to 6.4 km thick and holds 30 million km2 of ice. The Greenland ice sheet covers about 1.7 million km2.

The Antarctic ice sheet is the largest block of ice on Earth. It covers more than 14 million square kilometers (5.4 million square miles) and contains about 30 million cubic kilometers (7.2 million cubic miles) of water.

The Antarctic ice sheet is about 2 kilometers (1.2 miles) thick. If it melted, sea level would rise by about 60 meters (200 feet).

The Greenland ice sheet is much smaller than the Antarctic Ice sheet, only about 1.7 million square kilometers (656,000 square miles). It is still the second-largest body of ice on the planet.

The Greenland ice sheet interacts much more dynamically with the ocean than the Antarctic ice sheet. The annual snow accumulation rate is more than double that of Antarctica. Glacial melt happens across about half of the Greenland ice sheet, whereas it is much more isolated on the far western part of Antarctica. Greenland's ice shelves break up much faster than those surrounding Antarctica.

Both the Antarctic and Greenland ice sheets have caused the land under them to sink. Eastern Antarctica is about 2.5 kilometers (1.6 miles) below sea level because of the colossal weight of the ice sheet above it.

Credit: National Geographic

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WHAT ARE MORAINE RIDGES?

The variety of loose rocks and sediments dumped over landscape give evidence about the type of glacier and glaciation that took place in the area. A moraine ridge is the landform created by the debris left by a glacier after it has moved away. Moraine ridges are given names according to the size of debris and how they were formed. Examples are: lateral moraine, recessional moraine, medial moraine and ground moraine.

A moraine is material left behind by a moving glacier. This material is usually soil and rock. Just as rivers carry along all sorts of debris and silt that eventually builds up to form deltas, glaciers transport all sorts of dirt and boulders that build up to form moraines.

Moraines only show up in places that have, or used to have, glaciers. Glaciers are extremely large, moving rivers of ice. Glaciers shape the landscape in a process called glaciation. Glaciation can affect the land, rocks, and water in an area for thousands of years. That is why moraines are often very old.

 

Lateral Moraine

A lateral moraine forms along the sides of a glacier. As the glacier scrapes along, it tears off rock and soil from both sides of its path. This material is deposited as lateral moraine at the top of the glacier’s edges. Lateral moraines are usually found in matching ridges on either side of the glacier. The glacier pushes material up the sides of the valley at about the same time, so lateral moraines usually have similar heights.

Medial Moraine

A medial moraine is found on top of and inside an existing glacier. Medial moraines are formed when two glaciers meet. Two lateral moraines from the different glaciers are pushed together. This material forms one line of rocks and dirt in the middle of the new, bigger glacier.

Supraglacial Moraine

A supraglacial moraine is material on the surface of a glacier. Lateral and medial moraines can be supraglacial moraines. Supraglacial moraines are made up of rocks and earth that have fallen on the glacier from the surrounding landscape. Dust and dirt left by wind and rain become part of supraglacial moraines. Sometimes the supraglacial moraine is so heavy; it blocks the view of the ice river underneath.

Ground Moraine

Ground moraines often show up as rolling, strangely shaped land covered in grass or other vegetation. They don’t have the sharp ridges of other moraines. A ground moraine is made of sediment that slowly builds up directly underneath a glacier by tiny streams, or as the result of a glacier meeting hills and valleys in the natural landscape. When a glacier melts, the ground moraine underneath is exposed.

Terminal Moraine

A terminal moraine is also sometimes called an end moraine. It forms at the very end of a glacier, telling scientists today important information about the glacier and how it moved. At a terminal moraine, all the debris that was scooped up and pushed to the front of the glacier is deposited as a large clump of rocks, soil, and sediment.

Credit: National Geographic

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WHAT IS A BLOWHOLE?

Sometimes, the rocks along a coastline have a crevice or hole just above the low-tide mark. When the high tide rushes in, the crevice fills up with water, which tries to escape through this narrow hole. The build-up of pressure sprays out the water as an upward plume with a loud sound. This is a blowhole. Over time, a blowhole can create caves or even a pool of water near the coast.

When sea caves grow towards the land and upwards creating a vertical shaft that exposed on the surface, it results in a blowhole. Water often gushes out at the top part of the landform when waves move to the sea cave with significant force. The activities of the blowhole depend on the sea conditions as well as its geometry and that of the sea cave. A blowhole is characterized by an opening on the ground and a connection to an opening which interacts with the sea, mostly a cave.

Sea Caves are a common feature along the coasts and are formed through mechanical erosion of cliffs. Parts of weakness in the cliffs are weathered out by wave action thereby forming large cavities known as sea caves. These caves are regularly exposed to waves. Hydraulic pressure, built up by a succession of waves, eventually carves out a hole at the top of the cave to create an opening for water pressure to be expelled as a jet of spray. A blowhole can also be formed when lava flows make openings in the ground which extend towards the sea. The landform manifests as a crack or fissure once formed.

Credit: World Atlas

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What is a spit?

A spit is a narrow, extended piece of land that develops where a coastline sharply turns in towards the landmass. Attached to the coast at one end, the spit seems to grow out of it, as the movement of waves and tides deposits sand and pebbles at the angle of the landmass. The other end extends out into the sea, growing longer over time as more debris accumulates along it.

Spit is a landform in geography that is created from the deposition of the sand by the tide movements. One end of the spit remains attached to the mainland while the other end is open out in the water. It is narrow and elongated. Also known as sandspit, this type of landform is found off the coasts or the lake shores.

Spits are usually formed when re-entrance takes place by the longshore drift process from longshore currents. When waves at an oblique angle meet the beach, drift occurs. There is a deposit of sediment in a narrow strip in zigzag pattern moving down the beach. The same waves also cause longshore currents that complement the formation of the spit.

At the re-entrance, the longshore current spreads out or dissipates and not being able to carry the full load, drops much of the sediment which is called deposition. The longshore or littoral drift continues to transport sediment with the help of this submerged bar of deposit into the open waters alongside the beach in the direction the waves are breaking

This process forms an above-water spit. The formation of spit will continue out into the sea until the water pressure obstructs in the deposition of sand. As it grows, it becomes stable and often fertile; vegetation starts to grow and supports habitation.

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WHICH PLACE HOLDS THE RECORD FOR RECEIVING THE HIGHEST RAINFALL IN INDIA?

Mawsynram is a town in the East Khasi Hills district of Meghalaya state in Northeastern India, 60.9 kilometres from Shillong, the state capital. Mawsynram receives the highest rainfall in India. It is reportedly the wettest place on Earth, with an average annual rainfall of 11,872 millimetres (467.4 in), According to the Guinness Book of World Records, Mawsynram received 26,000 millimetres (1,000 in) of rainfall in 1985. Mawsynram received 745.2 mm of rainfall on 19 August 2015, probably the highest rainfall received by the town in recent times.] On June 17th 2022, Mawsynram set a new record by receiving 1003.6 mm in a span of 24 hours which has now become its highest single day record for the month of June and for its all time single day record beating its former record of 944.7 mm on June 7th 1966. 

Mawsynram is located at 25° 18? N, 91° 35? E, at an altitude of about 1,400 metres (4,600 ft), 15 km west of Cherrapunji, in the Khasi Hills in the state of Meghalaya (India). Under the Köppen climate classification, Mawsynram features a subtropical highland climate (Cwb) with an extraordinarily showery, rainy and long monsoonal season and a short dry season. Based on the data of a recent few decades, it appears to be the wettest place in the world, or the place with the highest average annual rainfall. Mawsynram receives over 10,000 millimeters of rain in an average year, and the vast majority of the rain it gets falls during the monsoon months. A comparison of rainfalls for Cherrapunji and Mawsynram for some years is given in Table 1. Mawsynram receives the highest rainfall in India. Although it is reportedly the wettest place on Earth, with an average annual rainfall of 11,872 millimetres (467.4 in), this claim is disputed by Lloró, Colombia, which reported an average yearly rainfall of 12,717 millimetres (500.7 in) between 1952 and 1989 and López de Micay, also in Colombia, which reported 12,892 mm (507.6 in) per year between 1960 and 2012. According to the records observed by the Indian Meterological Department, it was seen that while its neighbour, Cherrapunji is having a significant decreasing trend in rainfall, Mawsynram on the other hand is experiencing a slight increase in its rainfall pattern which put its average annual rainfall from 1950 to 2000 at 12393 mm and from 2000 to 2020 at 12120 mm. The precipitation table below shows the average monthly record from 1950-2000.

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WHAT IS WETLANDS?

An area of land that is either covered by water or saturated with water, wetlands are those areas where water covers the soil. While most scientists consider swamps, bogs, and marshes to be the three main kinds of wetlands, there are other types like peatlands, sloughs, and mires as well. Even though wetlands were seen as wastelands for most of history as they don't support development, it has since been realised that these are among the most valuable ecosystems on Earth. Governments began recognising the value of wetlands from the 1970s and laws have been put in place in parts of the world to protect wetlands.

Categories of Wetlands

Wetlands vary widely because of regional and local differences in soils, topography, climate, hydrology, water chemistry, vegetation and other factors, including human disturbance. Indeed, wetlands are found from the tundra to the tropics and on every continent except Antarctica. Two general categories of wetlands are recognized: coastal or tidal wetlands and inland or non-tidal wetlands.

Coastal/Tidal Wetlands

Coastal/tidal wetlands in the United States, as their name suggests, are found along the Atlantic, Pacific, Alaskan and Gulf coasts. They are closely linked to our nation's estuaries where sea water mixes with fresh water to form an environment of varying salinities. The salt water and the fluctuating water levels (due to tidal action) combine to create a rather difficult environment for most plants. Consequently, many shallow coastal areas are unvegetated mud flats or sand flats. Some plants, however, have successfully adapted to this environment. Certain grasses and grasslike plants that adapt to the saline conditions form the tidal salt marshes that are found along the Atlantic, Gulf, and Pacific coasts. Mangrove swamps, with salt-loving shrubs or trees, are common in tropical climates, such as in southern Florida and Puerto Rico. Some tidal freshwater wetlands form beyond the upper edges of tidal salt marshes where the influence of salt water ends.

Inland/Non-tidal Wetlands

Inland/non-tidal wetlands are most common on floodplains along rivers and streams (riparian wetlands), in isolated depressions surrounded by dry land (for example, playas, basins and "potholes"), along the margins of lakes and ponds, and in other low-lying areas where the groundwater intercepts the soil surface or where precipitation sufficiently saturates the soil (vernal pools and bogs). Inland wetlands include marshes and wet meadows dominated by herbaceous plants, swamps dominated by shrubs, and wooded swamps dominated by trees. Certain types of inland wetlands are common to particular regions of the country. 

Many of these wetlands are seasonal (they are dry one or more seasons every year), and, particularly in the arid and semiarid West, may be wet only periodically. The quantity of water present and the timing of its presence in part determine the functions of a wetland and its role in the environment. Even wetlands that appear dry at times for significant parts of the year -- such as vernal pools-- often provide critical habitat for wildlife adapted to breeding exclusively in these areas.

Credit : EPA 

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