It lies east-northeast of the Santa Cruz Islands (belonging to the Solomons), southeast of Nauru, south of Kiribati, west of Tokelau, northwest of Samoa and Wallis and Futuna and north of Fiji.

The soils of Tuvalu's islands are usually shallow, porous, alkaline, coarse-textured, with carbonate mineralogy and high pH values of up to 8.2 to 8.9.

[9] 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.

[11] 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.

[15] The most common trees found on all islands are coconut (Cocos nucifera) stands, hibiscus (Hibiscus tiliaceus), papaya (Carica papaya), pandanus (Pandanus tectorius), salt bush (Scaevola taccada), Premna serratifolia, Tournefortia samoensis, zebra wood (Guettarda speciosa), Kanava (Cordia subcordata), (beach cordia) and terminalia (Terminalia samoensis).

Indigenous broadleaf species, including Fetau (Calophyllum inophyllum), make up single trees or small stands around the coastal margin.

[19] 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:[20] Charles Hedley (1896) identified the uses of plants and trees from the native broadleaf forest as including:[21] Thaman (1992) provides a literature review of the ethnobiology of the Pacific Islands.

[22] Tuvalu experiences the effects of El Niño and La Niña that flow from changes in ocean temperatures in equatorial and central Pacific.

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.

[50][51] Despite passing over 500 km (310 mi) 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.

Nanumaga, Niutao, Niulakita are reef islands and the six true atolls are Funafuti, Nanumea, Nui, Nukufetau, Nukulaelae and Vaitupu.

[62] The eastern shoreline of Fongafale in the Funafuti lagoon (Te Namo) was modified during World War II; several piers were constructed, beach areas filled, and deep water access channels were excavated.

[17] Also important are a range of land snails, misa (Melampus spp) used to make shell leis (ula) and traditional handicrafts,[71] which includes the decoration of mats, fans and wall hangings.

[72] Since there are no streams or rivers and groundwater is not potable, most water needs must be met by catchment systems with storage facilities; beachhead erosion because of the use of sand for building materials; excessive clearance of forest undergrowth for use as fuel; damage to coral reefs from the bleaching of the coral as a consequence of the increase of the ocean temperatures and acidification from increased levels of carbon dioxide; Tuvalu is very concerned about global increases in greenhouse gas emissions and their effect on rising sea levels, which threaten the country's underground water table.

Tuvalu has adopted a national plan of action as the observable transformations over the last ten to fifteen years show Tuvaluans that there have been changes to the sea levels.

[76] Further research by Kench et al., published in 2018 identifies rising sea levels as creating an increased transfer of wave energy across the reef surfaces of the atolls of Tuvalu, which shifts sand, resulting in accretion to island shorelines.

[78] The storm surge created a wall of coral rubble along the ocean side of Fongafale and Funafala that was about 10 miles (16 km) long, and about 10 to 20 feet (3.0 to 6.1 m) thick at the bottom.

[83][84] Tuvalu experiences westerly gales and heavy rain from October to March – the period that is known as Tau-o-lalo; with tropical temperatures moderated by easterly winds from April to November.

In the low areas of Funafuti the sea water can be seen bubbling up through the porous coral rock to form pools with each high tide.

[87][88][89] Since 1994 a project has been in development to assess the environmental impact of transporting sand from the lagoon to fill all the borrow pits and low-lying areas on Fongafale.

[91] The project was carried out in 2015 with 365,000 sqm of sand being dredged from the lagoon to fill the holes and improve living conditions on the island.

Further projects that are part of TCAP are capital works on the outer islands of Nanumea and Nanumaga aimed at reducing exposure to coastal damage resulting from storms.

[93] In May 2019, TCAP signed an agreement with Fugro, for it to carry out an airborne LIDAR (Light Detection and Ranging) survey across the nine islands of Tuvalu.

[94] This aerial survey will provide high quality baseline data to assess the relationship between water levels and wave dynamics and their impact on the islands of Tuvalu.

Tuvalu is in the process of completing its accession to the Basel Convention to protect human health and the environment against the adverse effects that may result from the generation, transboundary movements and management of hazardous and other wastes.

From this point it rises vertically, like an enormous pillar, till reaches the surface in the form of a reef enclosing a lagoon of irregular size, but of which the extremities give a measurement of 13.5 by 10.0 miles".

[99]The investigation of groundwater dynamics of Fongafale Islet, Funafuti, show that tidal forcing results in salt water contamination of the surficial aquifer during spring tides.

About half of Fongafale islet is reclaimed swamp that contains porous, highly permeable coral blocks that allow the tidal forcing of salt water.

These topographic changes are exacerbated by the groundwater dynamics of the islet, as tidal forcing pushes salt water into the surficial aquifer during spring tides.

Tropical cyclones and other storm events also result in wave wash over and extreme high water also occurs during spring tides.