1.
Tuvalu
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It comprises three reef islands and six true atolls spread out between the latitude of 5° to 10° south and longitude of 176° to 180°, west of the International Date Line. Tuvalu has a population of 10,640, the total land area of the islands of Tuvalu is 26 square kilometres. The first inhabitants of Tuvalu were Polynesians, in 1568, Spanish navigator Álvaro de Mendaña was the first European to sail through the archipelago, sighting the island of Nui during his expedition in search of Terra Australis. In 1819 the island of Funafuti was named Ellices Island, the name Ellice was applied to all nine islands after the work of English hydrographer Alexander George Findlay. A referendum was held in December 1974 to determine whether the Gilbert Islands, as a consequence of the referendum, the Gilbert and Ellice Islands colony ceased to exist on 1 January 1976 and the separate British colonies of Kiribati and Tuvalu came into existence. Tuvalu became fully independent within the Commonwealth on 1 October 1978, on 5 September 2000 Tuvalu became the 189th member of the United Nations. The origins of the people of Tuvalu are addressed in the theories regarding migration into the Pacific that began about 3000 years ago, during pre-European-contact times there was frequent canoe voyaging between the nearer islands including Samoa and Tonga. Eight of the nine islands of Tuvalu were inhabited, thus the name, Tuvalu, possible evidence of fire in the Caves of Nanumanga may indicate human occupation for thousands of years. The stories as to the ancestors of the Tuvaluans vary from island to island, on Niutao, Funafuti and Vaitupu the founding ancestor is described as being from Samoa, whereas on Nanumea the founding ancestor is described as being from Tonga. Mendaña made contact with the islanders but was unable to land, during Mendañas second voyage across the Pacific he passed Niulakita on 29 August 1595, which he named La Solitaria. Captain John Byron passed through the islands of Tuvalu in 1764 during his circumnavigation of the globe as captain of the Dolphin, Byron charted the atolls as Lagoon Islands. Chambers and Doug Munro identified Niutao as the island that Francisco Mourelle de la Rúa sailed past on 5 May 1781, mourelles map and journal named the island El Gran Cocal, however, the latitude and longitude was uncertain. Longitude could only be reckoned crudely as accurate chronometers were unavailable until the late 18th century, the name Ellice was applied to all nine islands after the work of English hydrographer Alexander George Findlay. In 1820 the Russian explorer Mikhail Lazarev visited Nukufetau as commander of the Mirny, Louis Isidore Duperrey, captain of La Coquille, sailed past Nanumanga in May 1824 during a circumnavigation of the earth. A Dutch expedition found Nui on the morning of 14 June 1825, whalers began roving the Pacific, although visiting Tuvalu only infrequently because of the difficulties of landing on the atolls. Captain George Barrett of the Nantucket whaler Independence II has been identified as the first whaler to hunt the waters around Tuvalu, in November 1821 he bartered coconuts from the people of Nukulaelae and also visited Niulakita. A shore camp was established on Sakalua islet of Nukufetau, where coal was used to melt down the whale blubber, the Rev. A. W. Elekana began proselytising Christianity. He was trained at Malua Theological College, a London Missionary Society school in Samoa, in 1865 the Rev. A. W. Murray of the LMS – a Protestant congregationalist missionary society – arrived as the first European missionary where he too proselytised among the inhabitants of Tuvalu
2.
Climate change in Tuvalu
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Global warming is a concern in Tuvalu since the average height of the islands is less than 2 metres above sea level, with the highest point of Niulakita being about 4.6 metres above sea level. Tuvalu could be one of the first nations to experience the effects of sea level rise, not only could parts of the island be flooded but the rising saltwater table could also destroy deep rooted food crops such as coconut, pulaka, and taro. Tuvalu participates in the operations of the Secretariat of the Pacific Regional Environment Programme, the climate of the Pacific region at the equator is influenced by a number of factors, the science of which is the subject of continuing research. The SPREP described the climate of Tuvalu as being, The sea level in Tuvalu varies as a consequence of a range of atmospheric and oceanographic influences. The trade winds that push surface water westward create this zonal tilting of sea level on the equator, below the equator a higher sea level can also be found about 20° to 40° south. This has an effect on sea levels, the Perigean spring tide can result in seawater flooding low-lying areas of the islands of Tuvalu. In 1978 a tide gauge was installed at Funafuti by the University of Hawaii. It has measured a sea rise of 1.2 mm per year over 23 years—a figure consistent with the Intergovernmental Panel on Climate Change global mean estimate of 1 to 2 mm per year over the 20th century. The 40 cm rise in sea level predicted by the IPCC by the end of the 21st century could have significant effects for Tuvalu, the highest elevation is 4.6 metres above sea level on Niulakita, which gives Tuvalu the second-lowest maximum elevation of any country. However, the highest elevations are typically in narrow storm dunes on the side of the islands which are prone to over topping in tropical cyclones. In March 2015 the storm created by Cyclone Pam resulted in waves of 3 metres to 5 metres breaking over the reef of the outer islands caused damage to houses, crops. On Nui the sources of water were destroyed or contaminated. Tuvalu is also affected by spring tide events, which raise the sea level higher than a normal high tide. The highest peak tide recorded by the Tuvalu Meteorological Service was 3.4 metres on 24 February 2006 and again on 19 February 2015. In the future, sea level rise may threaten to submerge the nation entirely as it is estimated that a sea rise of 20–40 centimetres in the next 100 years could make Tuvalu uninhabitable. There remains the risk that the response of atolls and reef islands does not result in stable islands as tropical cyclones can strip the low-lying islands of their vegetation. Tepuka Vili Vili islet of Funafuti atoll was devastated by Cyclone Meli in 1979, with all its vegetation, vasafua islet, part of the Funafuti Conservation Area, was severely damaged by Cyclone Pam in 2015. The coconut palms were washed away, leaving the islet as a sand bar, gradual sea-level rise also allows for coral polyp activity to raise the atolls with the sea level
3.
Drought
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A drought is a period of below-average precipitation in a given region, resulting in prolonged shortages in its water supply, whether atmospheric, surface water or ground water. A drought can last for months or years, or may be declared after as few as 15 days and it can have a substantial impact on the ecosystem and agriculture of the affected region and harm to the local economy. Annual dry seasons in the tropics significantly increase the chances of a drought developing, periods of heat can significantly worsen drought conditions by hastening evaporation of water vapour. Many plant species, such as those in the family Cactaceae, have drought tolerance adaptations like reduced leaf area, some others survive dry periods as buried seeds. Semi-permanent drought produces arid biomes such as deserts and grasslands, prolonged droughts have caused mass migrations and humanitarian crises. Most arid ecosystems have inherently low productivity, the most prolonged drought ever in the world in recorded history occurred in the Atacama Desert in Chile. Mechanisms of producing precipitation include convective, stratiform, and orographic rainfall, precipitation can be divided into three categories, based on whether it falls as liquid water, liquid water that freezes on contact with the surface, or ice. Drought are mainly course by in low rain areas, if these factors do not support precipitation volumes sufficient to reach the surface over a sufficient time, the result is a drought. Once a region is within drought, feedback mechanisms such as local arid air, hot conditions which can promote warm core ridging, within the tropics, distinct, wet and dry seasons emerge due to the movement of the Intertropical Convergence Zone or Monsoon trough. The dry season greatly increases drought occurrence, and is characterized by its low humidity, with watering holes, because of the lack of these watering holes, many grazing animals are forced to migrate due to the lack of water and feed to more fertile spots. Examples of such animals are zebras, elephants, and wildebeest, because of the lack of water in the plants, bushfires are common. Since water vapor becomes more energetic with increasing temperature, more water vapor is required to increase relative humidity values to 100% at higher temperatures, periods of warmth quicken the pace of fruit and vegetable production, increase evaporation and transpiration from plants, and worsen drought conditions. Drier and hotter weather occurs in parts of the Amazon River Basin, Colombia, winters during the El Niño are warmer and drier than average conditions in the Northwest, northern Midwest, and northern Mideast United States, so those regions experience reduced snowfalls. Conditions are also drier than normal from December to February in south-central Africa, mainly in Zambia, Zimbabwe, Mozambique, and Botswana. Direct effects of El Niño resulting in drier conditions occur in parts of Southeast Asia and Northern Australia, increasing bush fires, worsening haze, drier-than-normal conditions are also in general observed in Queensland, inland Victoria, inland New South Wales, and eastern Tasmania from June to August. As warm water spreads from the west Pacific and the Indian Ocean to the east Pacific, it causes extensive drought in the western Pacific. Singapore experienced the driest February in 2014 since records began in 1869, with only 6.3 mm of rain falling in the month, the years 1968 and 2005 had the next driest Februaries, when 8.4 mm of rain fell. Human activity can directly trigger exacerbating factors such as farming, excessive irrigation, deforestation
4.
Oceania
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Oceania, also known as Oceanica, is a region centred on the islands of the tropical Pacific Ocean. The term is used more specifically to denote a continent comprising Australia. The term was coined as Océanie circa 1812 by geographer Conrad Malte-Brun, the word Océanie is a French word derived from the Latin word oceanus, and this from the Greek word ὠκεανός, ocean. Natives and inhabitants of this region are called Oceanians or Oceanicans, as an ecozone, Oceania includes all of Micronesia, Fiji, and all of Polynesia except New Zealand. New Zealand, along with New Guinea and nearby islands, part of the Philippine islands, Australia, the Solomon Islands, Vanuatu, in geopolitical terms, however, New Zealand, the Solomon Islands, Vanuatu and New Caledonia are almost always considered part of Oceania. Australia and Papua New Guinea are usually considered part of Oceania along with the Maluku Islands, puncak Jaya in Papua is often considered the highest peak in Oceania. Oceania was originally conceived as the lands of the Pacific Ocean and it comprised four regions, Polynesia, Micronesia, Malaysia, and Melanesia. The area extends to Sumatra in the west, the Bonin Islands in the northwest, the Hawaiian Islands in the northeast, Rapa Nui and Sala y Gómez Island in the east, and Macquarie Island in the south. Not included are the Pacific islands of Taiwan, the Ryukyu Islands and the Japanese archipelago, all on the margins of Asia, and the Aleutian Islands of North America. The islands at the extremes of Oceania are Bonin, a politically integral part of Japan, Hawaii, a state of the United States. There is also a geographic definition that excludes land on the Sunda Plate. Biogeographically, Oceania is used as a synonym for either the Australasian ecozone or the Pacific ecozone, Oceania is one of eight terrestrial ecozones, which constitute the major ecological regions of the planet. The Oceania ecozone includes all of Micronesia, Fiji, and all of Polynesia except New Zealand, New Zealand, New Guinea, Melanesia apart from Fiji, and Australia constitute the separate Australasian ecozone. The Malay Archipelago is part of the Indomalaya ecozone, related to these concepts are Near Oceania, that part of western Island Melanesia which has been inhabited for tens of millennia, and Remote Oceania which is more recently settled. The term is used to denote a continent comprising Australia. New Zealand forms the corner of the Polynesian Triangle. Its indigenous Māori constitute one of the cultures of Polynesia. It is also, however, considered part of Australasia, the history of Oceania in the medieval period was synonymous with the history of the indigenous peoples of Australasia, Micronesia, Melanesia, Polynesia
5.
Tropical cyclone
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Depending on its location and strength, a tropical cyclone is referred to by names such as hurricane, typhoon /taɪˈfuːn/, tropical storm, cyclonic storm, tropical depression, and simply cyclone. A hurricane is a storm that occurs in the Atlantic Ocean and northeastern Pacific Ocean, a typhoon occurs in the northwestern Pacific Ocean, Tropical cyclones typically form over large bodies of relatively warm water. They derive their energy through the evaporation of water from the ocean surface and this energy source differs from that of mid-latitude cyclonic storms, such as noreasters and European windstorms, which are fueled primarily by horizontal temperature contrasts. The strong rotating winds of a tropical cyclone are a result of the conservation of momentum imparted by the Earths rotation as air flows inwards toward the axis of rotation. As a result, they form within 5° of the equator. Tropical cyclones are typically between 100 and 2,000 km in diameter, Tropical refers to the geographical origin of these systems, which form almost exclusively over tropical seas. Cyclone refers to their nature, with wind blowing counterclockwise in the Northern Hemisphere. The opposite direction of circulation is due to the Coriolis effect, in addition to strong winds and rain, tropical cyclones are capable of generating high waves, damaging storm surge, and tornadoes. They typically weaken rapidly over land where they are cut off from their energy source. For this reason, coastal regions are vulnerable to damage from a tropical cyclone as compared to inland regions. Heavy rains, however, can cause significant flooding inland, though their effects on human populations are often devastating, tropical cyclones can relieve drought conditions. They also carry heat away from the tropics and transport it toward temperate latitudes. Tropical cyclones are areas of low pressure in the troposphere. On Earth, the pressures recorded at the centers of tropical cyclones are among the lowest ever observed at sea level, the environment near the center of tropical cyclones is warmer than the surroundings at all altitudes, thus they are characterized as warm core systems. The near-surface wind field of a cyclone is characterized by air rotating rapidly around a center of circulation while also flowing radially inwards. At the outer edge of the storm, air may be nearly calm, however, due to the Earths rotation, as air flows radially inward, it begins to rotate cyclonically in order to conserve angular momentum. At an inner radius, air begins to ascend to the top of the troposphere and this radius is typically coincident with the inner radius of the eyewall, and has the strongest near-surface winds of the storm, consequently, it is known as the radius of maximum winds. Once aloft, air flows away from the center, producing a shield of cirrus clouds
6.
Rain
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Rain is liquid water in the form of droplets that have condensed from atmospheric water vapor and then precipitated—that is, become heavy enough to fall under gravity. Rain is a component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides suitable conditions for many types of ecosystems, as well as water for power plants. The major cause of production is moisture moving along three-dimensional zones of temperature and moisture contrasts known as weather fronts. If enough moisture and upward motion is present, precipitation falls from convective clouds such as cumulonimbus which can organize into narrow rainbands. On the leeward side of mountains, desert climates can exist due to the dry air caused by downslope flow which causes heating and drying of the air mass, the movement of the monsoon trough, or intertropical convergence zone, brings rainy seasons to savannah climes. The urban heat island effect leads to increased rainfall, both in amounts and intensity, downwind of cities, global warming is also causing changes in the precipitation pattern globally, including wetter conditions across eastern North America and drier conditions in the tropics. The globally averaged annual precipitation over land is 715 mm, climate classification systems such as the Köppen climate classification system use average annual rainfall to help differentiate between differing climate regimes. Rainfall is measured using rain gauges, rainfall amounts can be estimated by weather radar. Rain is also known or suspected on other planets, where it may be composed of methane, neon, sulfuric acid, or even iron rather than water. Air contains water vapor, and the amount of water in a mass of dry air. The amount of moisture in air is commonly reported as relative humidity. How much water vapor a parcel of air can contain before it becomes saturated, warmer air can contain more water vapor than cooler air before becoming saturated. Therefore, one way to saturate a parcel of air is to cool it, the dew point is the temperature to which a parcel must be cooled in order to become saturated. There are four mechanisms for cooling the air to its dew point, adiabatic cooling, conductive cooling, radiational cooling. Adiabatic cooling occurs when air rises and expands, the air can rise due to convection, large-scale atmospheric motions, or a physical barrier such as a mountain. Conductive cooling occurs when the air comes into contact with a surface, usually by being blown from one surface to another. Radiational cooling occurs due to the emission of infrared radiation, either by the air or by the surface underneath, evaporative cooling occurs when moisture is added to the air through evaporation, which forces the air temperature to cool to its wet-bulb temperature, or until it reaches saturation
7.
Drinking water
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Drinking water, also known as potable water or improved drinking water, is water that is safe to drink or to use for food preparation, without risk of health problems. Globally, in 2015, 91% of people had access to suitable for drinking. Nearly 4.2 billion had access to tap water while another 2.4 billion had access to wells or public taps,1.8 billion people still use an unsafe drinking water source which may be contaminated by feces. This can result in infectious diarrhea such as cholera and typhoid among others, the amount of drinking water required is variable. It depends on activity, age, health issues. It is estimated that the average American drinks about one litre of water a day with 95% drinking less than three litres per day, for those working in a hot climate, up to 16 liters a day may be required. Water makes up about 60% of weight in men and 55% of weight in women, infants are about 70% to 80% water while the elderly are around 45%. Typically in developed countries, tap water meets drinking water quality standards, other typical uses include washing, toilets, and irrigation. Greywater may also be used for toilets or irrigation and its use for irrigation however may be associated with risks. Water may also be due to levels of toxins or suspended solids. Reduction of waterborne diseases and development of water resources is a major public health goal in developing countries. Bottled water is sold for consumption in most parts of the world. The word potable came into English from the Late Latin potabilis, the amount of drinking water required is variable. It depends on activity, age, health, and environmental conditions. It is estimated that the average American drinks about one litre of water a day with 95% drinking less than three litres per day, for those working in a hot climate, up to 16 litres per day may be required. Some health authorities have suggested that at least eight glasses of eight fl oz each are required by an adult per day, the British Dietetic Association recommends 1.8 litres. However, various reviews of the evidence performed in 2002 and 2008 could not find any scientific evidence recommending eight glasses of water per day. An individuals thirst provides a guide for how much water they require rather than a specific
8.
Atoll
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An atoll, sometimes called a coral atoll, is a ring-shaped coral reef including a coral rim that encircles a lagoon partially or completely. There may be coral islands/cays on the rim, the coral of the atoll often sits atop the rim of an extinct seamount or volcano which has eroded or subsided partially beneath the water. The lagoon forms over the crater or caldera while the higher rim remains above water or at shallow depths that permit the coral to grow. For the atoll to persist, continued erosion or subsidence must be at a slow enough to permit reef growth upwards and outwards to replace the lost height. The word atoll comes from the Dhivehi word atholhu, meaning an administrative subdivision, the distribution of atolls around the globe is instructive, most of the worlds atolls are in the Pacific Ocean and Indian Ocean. The Atlantic Ocean has no large groups of atolls, other than eight atolls east of Nicaragua that belong to the Colombian department of San Andres and Providencia in the Caribbean. Reef-building corals will thrive only in tropical and subtropical waters of oceans and seas. The northernmost atoll of the world is Kure Atoll at 28°24 N, the southernmost atolls of the world are Elizabeth Reef at 29°58 S, and nearby Middleton Reef at 29°29 S, in the Tasman Sea, both of which are part of the Coral Sea Islands Territory. The next southerly atoll is Ducie Island in the Pitcairn Islands Group, at this latitude coral reefs would not develop without the warming waters of the Gulf Stream. However, Bermuda is termed a pseudo-atoll because its general form, while there is no atoll directly on the equator, the closest atoll to the Equator is Aranuka of Kiribati, with its southern tip just 12 km north of the equator. In most cases, the area of an atoll is very small in comparison to the total area. Atoll islands are low lying, with their elevations less than 5 meters, measured by total area, Lifou is the largest raised coral atoll of the world, followed by Rennell Island. More sources however list as the largest atoll in the world in terms of land area Kiritimati, the remains of an ancient atoll as a hill in a limestone area is called a reef knoll. The second largest atoll by dry land area is Aldabra with 155 km², the largest atoll in terms of island numbers is Huvadhu Atoll in the south of the Maldives with 255 islands. In 1842, Charles Darwin explained the creation of coral atolls in the southern Pacific Ocean based upon observations made during a voyage aboard the HMS Beagle from 1831 to 1836. In time, subsidence carries the old volcano below the ocean surface, at this point, the island has become an atoll. Atolls are the product of the growth of marine organisms. Volcanic islands located beyond the water temperature requirements of hermatypic organisms become seamounts as they subside and are eroded away at the surface
9.
Groundwater
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Groundwater is the water present beneath Earths surface in soil pore spaces and in the fractures of rock formations. A unit of rock or a deposit is called an aquifer when it can yield a usable quantity of water. The depth at which pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from, and eventually flows to, the naturally, natural discharge often occurs at springs and seeps. Groundwater is also withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrogeology, Groundwater is hypothesized to provide lubrication that can possibly influence the movement of faults. It is likely that much of Earths subsurface contains some water, Groundwater may not be confined only to Earth. The formation of some of the landforms observed on Mars may have influenced by groundwater. There is also evidence that water may also exist in the subsurface of Jupiters moon Europa. Groundwater is often cheaper, more convenient and less vulnerable to pollution than surface water, therefore, it is commonly used for public water supplies. For example, groundwater provides the largest source of water storage in the United States. Underground reservoirs contain far more water than the capacity of all surface reservoirs and lakes in the US, many municipal water supplies are derived solely from groundwater. Polluted groundwater is less visible, but more difficult to clean up, than pollution in rivers, Groundwater pollution most often results from improper disposal of wastes on land. An aquifer is a layer of substrate that contains and transmits groundwater. When water can flow directly between the surface and the zone of an aquifer, the aquifer is unconfined. The deeper parts of unconfined aquifers are more saturated since gravity causes water to flow downward. The upper level of this layer of an unconfined aquifer is called the water table or phreatic surface. Below the water table, where in general all pore spaces are saturated with water, is the phreatic zone, substrate with low porosity that permits limited transmission of groundwater is known as an aquitard
10.
American Samoa
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American Samoa is an unincorporated territory of the United States located in the South Pacific Ocean, southeast of Samoa. American Samoa consists of five islands and two coral atolls. The largest and most populous island is Tutuila, with the Manuʻa Islands, Rose Atoll, All islands except for Swains Island are part of the Samoan Islands, located west of the Cook Islands, north of Tonga, and some 300 miles south of Tokelau. To the west are the islands of the Wallis and Futuna group, the 2010 census showed a total population of 55,519 people. The total land area is 199 square kilometers, slightly more than Washington, American Samoa is the southernmost territory of the U. S. and one of two U. S. territories south of the Equator, along with the uninhabited Jarvis Island. Tuna products are the exports, and the main trading partner is the United States. American Samoa is noted for having the highest rate of enlistment of any U. S. state or territory. Most American Samoans are bilingual and can speak English and Samoan fluently, Samoan is the same language spoken in neighboring independent Samoa. Contact with Europeans began in the early 18th century, dutchman Jacob Roggeveen was the first known European to sight the Samoan Islands in 1722. This visit was followed by French explorer Louis-Antoine de Bougainville who named them the Navigator Islands in 1768, contact was limited before the 1830s, when English missionaries and traders began arriving. The site of battle is called Massacre Bay. Mission work in the Samoas had begun in late 1830 when John Williams of the London Missionary Society arrived from the Cook Islands, by that time, the Samoans had gained a reputation for being savage and warlike, as violent altercations had occurred between natives and European visitors. In March 1889, an Imperial German naval force entered a village on Samoa, three American warships then entered the Apia harbor and prepared to engage the three German warships found there. Before any shots were fired, a typhoon wrecked both the American and German ships, a compulsory armistice was then called because of the lack of any warships. Forerunners to the Tripartite Convention of 1899 were the Washington Conference of 1887, the Treaty of Berlin of 1889, the following year, the USA formally occupied its portion, a smaller group of eastern islands, one of which contains the noted harbor of Pago Pago. The Navy secured a Deed of Cession of Tutuila in 1900, the territory became known as the US Naval Station Tutuila. On July 17,1911, the US Naval Station Tutuila, in 1918 during the final stages of World War I, the flu pandemic had taken its toll, spreading rapidly from country to country. The result of Poyers quick actions earned him the Navy Cross from the US Navy, with this distinction, American Samoans regarded Poyer as their hero for what he had done to prevent the deadly disease
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