Geography of Tuvalu


The Western Pacific archipelagic nation of Tuvalu, formerly known as the Ellice Islands, is situated northeast of Australia and is approximately halfway between Australia and Hawaii. It lies east-northeast of the Santa Cruz Islands, southeast of Nauru, south of Kiribati, west of Tokelau, northwest of Samoa and Wallis and Futuna and north of Fiji. It is a very small island country of. Due to the spread-out islands it has the 38th largest Exclusive Economic Zone of. In size, it is the second-smallest country in Oceania.
The islands of Tuvalu consists of three reef islands and six atolls, containing approximately of reef platforms. The reef islands have a different structure to the atolls, and are described as reef platforms as they are smaller tabular reef platforms that do not have a salt-water lagoon, although they have a completely closed rim of dry land, with the remnants of a lagoon that has no connection to the open sea or that may be drying up. For example, Niutao has two lakes, which are brackish to saline, and are the degraded lagoon as the result of coral debris filling the lagoon.
The soils of Tuvalu's islands are usually shallow, porous, alkaline, and coarse-textured, with carbonate mineralogy and high pH values of up to 8.2 to 8.9. The soils are usually deficient in most of the important nutrients needed for plant growth, so garden beds need to be enhanced with mulch and fertiliser to increase their fertility. The Tuvalu islands have a total land area of only about 26 km2, less than.
The land is very low-lying, with narrow coral atolls. The highest elevation is above sea level on Niulakita. Over four decades, there had been a net increase in land area of the islets of 73.5 ha, although the changes are not uniform, with 74% increasing and 27% decreasing in size. The sea level at the Funafuti tide gauge has risen at 3.9 mm per year, which is approximately twice the global average. The rising sea levels are identified as creating an increased transfer of wave energy across reef surfaces, which shifts sand, resulting in accretion to island shorelines, although this process does not result in additional habitable land. As of March 2018 Enele Sopoaga, the prime minister of Tuvalu, stated that Tuvalu is not expanding and has gained no additional habitable land.
Tuvalu experiences two distinct seasons, a wet season from November to April and a dry season from May to October. Westerly gales and heavy rain are the predominant weather conditions from November to April, the period that is known as Tau-o-lalo, with tropical temperatures moderated by easterly winds from May to October.

Geography

Location:
Oceania, island group of nine islands comprising three reef islands and six true atolls in the South Pacific Ocean. The islands of Tuvalu are spread out between the latitude of 5° to 10° south and longitude of 176° to 180°, west of the International Date Line.
Geographic coordinates: to
Map references:
Oceania
Area:
total:
26 km2
land:
26 km2
water:
0 km2
Area – comparative:
0.1 times the size of Washington, DC
Land boundaries:
0 km
Coastline:
Maritime claims:
contiguous zone:
exclusive economic zone:
and
territorial sea:
Tuvalu's Exclusive Economic Zone covers an oceanic area of approximately.
On 29 August 2012 an Agreement between Tuvalu and Kiribati concerning their Maritime Boundary, was signed by their respective leaders that determined the boundary as being seaward of Nanumea and Niutao in Tuvalu on the one hand and Tabiteuea, Tamana and Arorae in Kiribati on the other hand, along the geodesics connecting the points of latitude and longitude set out in the agreement.
In October 2014 the prime ministers of Fiji and Tuvalu signed the Fiji-Tuvalu Maritime Boundary Treaty, which establishes the extent of the national areas of jurisdiction between Fiji and Tuvalu as recognized in international law under the 1982 United Nations Convention on the Law of the Sea.
Climate:
tropical; moderated by easterly trade winds ; westerly gales and heavy rain.
Terrain:
low-lying and narrow coral atolls.
Elevation extremes:
lowest point:
Pacific Ocean 0 m
highest point:
unnamed location, on Niulakita.
Extreme points:
File:Tuvalu - Funafuti - Approach.jpg|thumb|right|300px|Lat. and Long.
This is a list of the extreme points of Tuvalu, the points that are farther north, south, east or west than any other location:
  • Northernmost point – Lakena islet, Nanumea
  • Easternmost point – Niuoko islet, Nukulaelae
  • Southernmost point – Niulakita
  • Westernmost point – Lakena islet, Nanumea
Natural resources:
fish. coconut
Land use:
arable land:
0%
permanent crops:
60%
forest:
33.3%
other:
6.7%
Irrigated land:
0 km2

Trees and shrubs

Most common trees

Thaman described about 362 species or distinct varieties of vascular plants that have been recorded at some time on Tuvalu, of which only about 59 are possibly indigenous. The most common trees found on all islands are coconut stands, hibiscus, papaya, pandanus, salt bush, Premna serratifolia, Tournefortia samoensis, zebra wood, Kanava, and terminalia. Indigenous broadleaf species, including Fetau, make up single trees or small stands around the coastal margin. While Coconut palms are common in Tuvalu, they are usually cultivated rather than naturally seeding and growing. Tuvaluan traditional histories are that the first settlers of the islands planted Coconut palms as they were not found on the islands.
The two recorded mangrove species in Tuvalu are the common Togo and the red-flowered mangrove Sagale, which is only reported on Nanumaga, Niutao, Nui and Vaitupu. Mangrove ecosystems are protected under Tuvaluan law.
The land cover types found on Funafuti include inland broadleaf forest and woodland, coastal littoral forest and scrub, mangroves and wetlands, and coconut woodland and agroforest.

Native broadleaf forest

The native broadleaf forest is limited to 4.1% of the vegetation types on the islands of Tuvalu. The islets of the Funafuti Conservation Area have 40% of the remaining native broadleaf forest on Funafuti atoll. The native broadleaf forest of Funafuti would include the following species, that were described by Charles Hedley in 1896, which include the Tuvaluan name :
  • Fala or Screw Pine,
  • Puka or pouka,
  • Futu,
  • Fetau,
  • Ferra,, native fig
  • Fau or Fo fafini, or woman's fibre tree
  • Lakoumonong,
  • Lou,
  • Meili,, fern
  • Laukatafa, Asplenium nidus, bird's-nest fern
  • Milo or miro,
  • Ngashu or Naupaka,
  • Ngia or Ingia,, bush
  • Nonou or nonu,
  • Pukavai,
  • Sageta,, vine
  • Talla talla gemoa,, fern
  • Tausunu or tausoun,
  • Tonga or tongo,, found around swamps
  • Tulla tulla,, whose prostrate stems trailed for several feet over the ground
  • Valla valla,
The blossoms that are valued for their scent and for use in flower necklaces and headdresses include: Fetau, ; Jiali, ; Boua ; and Crinum.
Donald Gilbert Kennedy, the resident District Officer in the administration of the Gilbert and Ellice Islands Colony from 1932 to 1938, identified other trees found in the broadleaf forest:
  • Pua,
  • Kanava,
Charles Hedley identified the uses of plants and trees from the native broadleaf forest as including:
  • Food plants: Coconut; and Ferra, native fig.
  • Fibre: Coconut; Ferra; Fala, Screw Pine, Pandanus; Fau or Fo fafini, or woman's fibre tree.
  • Timber: Fau or Fo fafini; Pouka, ; Ngia or Ingia, ; Miro, ; and Tonga,.
  • Dye: Valla valla, ; Tonga, ; and Nonou,.
  • Scent: Fetau, ; Jiali, ; and Boua ; Valla valla, ; and Crinum.
  • Medicinal: Tulla tulla, ; Nonou, ; Tausoun, ; Valla valla, ; Talla talla gemoa ; Lou, ; and Lakoumonong,.
Thaman provides a literature review of the ethnobiology of the Pacific Islands.

Climate and natural hazards

El Niño and La Niña

Tuvalu experiences the effects of El Niño and La Niña that flow from changes in ocean temperatures in equatorial and central Pacific. El Niño effects increase the chances of tropical storms and cyclones; while La Niña effects increase the chances of drought conditions in Tuvalu. On 3 October 2011, drought conditions resulted in a state of emergency being declared as water reserves ran low. Typically the islands of Tuvalu receive between 200mm to 400mm of rainfall per month, however a weak La Niña effect causes a drought by cooling the surface of the sea around Tuvalu.

Tropical cyclones

Severe tropical cyclones are usually rare, but the low level of islands makes them very sensitive to sea-level rise. Tuvalu experienced an average of three cyclones per decade between the 1940s and 1970s, however eight occurred in the 1980s. The impact of individual cyclones is subject to variables including the force of the winds and also whether a cyclone coincides with high tides. A warning system, which uses the Iridium satellite network, was introduced in 2016 in order to allow outlying islands to be better prepare for natural disasters.
George Westbrook recorded a cyclone that struck Funafuti on 23–24 December 1883. A cyclone struck Nukulaelae on 17–18 March 1886. Captain Edward Davis of HMS Royalist, who visited the Ellice Group in 1892, recorded in the ship's diary that in February 1891 the Ellice Group was devastated by a severe cyclone. A cyclone caused severe damage to the islands in 1894.
Image:Tuvalu Meteorology Service.jpg| thumb|left|275px| Tuvalu Meteorological Service, Fongafale, Funafuti atoll
Cyclone Bebe caused severe damage to Funafuti during the 1972–73 South Pacific cyclone season. Funafuti's Tepuka Vili Vili islet was devastated by Cyclone Meli in 1979, with all its vegetation and most of its sand swept away during the cyclone. Cyclone Gavin was first identified during 2 March 1997, and was the first of three tropical cyclones to affect Tuvalu during the 1996–97 cyclone season with Cyclones Hina and Keli following later in the season. Cyclone Ofa had a major impact on Tuvalu in late January and early February 1990. On Vaitupu Island around 85 percent of residential homes, trees and food crops were destroyed, while residential homes were also destroyed on the islands of Niutao, Nui and Nukulaelae. The majority of the islands in Tuvalu reported damage to vegetation and crops especially bananas, coconuts and breadfruit, with the extent of damage ranging from 10 to 40 percent. In Funafuti sea waves flattened the Hurricane Bebe bank at the southern end of the airstrip, which caused sea flooding and prompted the evacuation of several families from their homes. In Nui and Niulakita there was a minor loss of the landscape because of sea flooding while there were no lives lost. Soon after the systems had impacted Tuvalu, a Disaster Rehabilitation Sub-Committee was appointed to evaluate the damage caused and make recommendations to the National Disaster Committee and to the Cabinet of Tuvalu, on what should be done to help rehabilitate the affected areas.
In March 2015 Cyclone Pam, the Category 5 cyclone that devastated Vanuatu, caused damage to houses, crops and infrastructure on the outer islands. A state of emergency was subsequently declared on 13 March. An estimated 45 percent of the nation's nearly 10,000 people were displaced, according to Prime Minister Enele Sopoaga. The three northern islands, Nanumea, Nanumanga and Niutao were badly affected by flooding as the result of storm surges. More than 400 people from the northern island of Nanumanga were moved to emergency accommodation in the school buildings, as well as another 85 families from Nukulaelae in the south of Tuvalu. On Nui the storm surges contaminated the water supplies and damaged septic tanks and grave sites. The central islands of Vaitupu and Nukufetau were also affected by flooding caused by storm surges. The Situation Report published on 30 March reported that on Nukufetau all the displaced people have returned to their homes.
Nui suffered the most damage of the three central islands ; with both Nui and Nukufetau suffering the loss of 90% of the crops. Of the three northern islands, Nanumanga suffered the most damage, with 60–100 houses flooded and damage to the health facility. Vasafua islet, part of the Funafuti Conservation Area, was severely damaged by Cyclone Pam. The coconut palms were washed away, leaving the islet as a sand bar.
Despite passing over to the south of the island nation, Cyclone Tino and its associated convergence zone impacted the whole of Tuvalu between January 16 - 19 of 2020.