Kiritimati is in the world's furthest forward time zone, UTC+14, and is therefore one of the first inhabited places on Earth to experience New Year's Day (see also Caroline Atoll, Kiribati).

Although it lies 2,460 km (1,530 mi) east of the 180th meridian, the Republic of Kiribati realigned the International Date Line in 1995, placing Kiritimati to the west of the dateline.

As such, some researchers have suggested that Kiritimati was used intermittently (likely by people from Tabuaeran to the north) as a place to gather resources such as birds and turtles in a similar fashion to the ethnographically documented use of the five central atolls of the Caroline Islands.

English and two teenagers were marooned on the island for a year and a half (1917–1919) as transport had stopped due to the Spanish flu breaking out in Tahiti and around the world.

English, thinking that the rescue ship was German and the war was still in effect, pulled his revolver on the admiral Jellicoe, causing a short standoff until some explanation defused the situation.

[d] Despite having sought acknowledgement of the issue regarding interpretation of the treaty, no Spanish government has made any attempt to assert sovereignty over Kiritimati, and the case remains a historical curiosity.

[20] The United Kingdom conducted its first hydrogen bomb test series, Grapple 1–3, at Malden Island from 15 May to 19 June 1957 and used Kiritimati as the operation's main base.

It has a paved runway with a length of 6,900 feet (2,103 m) and was for some time the only airport in Kiribati to serve the Americas, via an Air Pacific (now Fiji Airways) flight to Honolulu, Hawaii.

In July 2022 The Southern Cross NEXT 15,857 km submarine cable system, entered service,[37] connecting Los Angeles and Sydney with a dedicated 377 kilometers (one fiber pair) branch to Tabwakea, Kiritimati.

[1] In recent years, surfers have discovered that there are good waves during the Northern Hemisphere's winter season and there are interests developing to service these recreational tourists.

In the early 1950s, Wernher von Braun proposed using this island as a launch site for crewed spacecraft, based on its proximity to the equator, and the generally empty ocean down-range (east).

Kiritimati is a raised atoll, and although it does occasionally receive plenty of precipitation, little is retained given the porous carbonate rock, the thin soil, and the absence of dense vegetation cover on much of the island, while evaporation is constantly high.

The 1957 attempt to introduce the endangered Rimitara lorikeet (Vini kuhlii) has largely failed; a few birds seem to linger on, but the lack of abundant coconut palm forest, on which this tiny parrot depends, makes Kiritimati a suboptimal habitat for this species.

[1] Perhaps the most destructive of the recently introduced plants is sweetscent (Pluchea odorata), a camphorweed, which is considered an invasive weed as it overgrows and displaces herbs and grasses.

The introduced creeper Tribulus cistoides, despite having also spread conspicuously, is considered to be more beneficial than harmful to the ecosystem, as it provides good nesting sites for some seabirds.

As noted above, only the bokikokiko (Acrocephalus aequinoctialis), perhaps a few Rimitara lorikeets (Vini kuhlii) – if any remain at all – and the occasional eastern reef egret (Egretta sacra) make up the entire landbird fauna.

The most commonly seen migrants are ruddy turnstone (Arenaria interpres), Pacific golden plover (Pluvialis fulva), bristle-thighed curlew (Numenius tahitiensis), and wandering tattler (Tringa incana); other seabirds, waders, and even dabbling ducks can be encountered every now and then.

[1] Around 7 October (±5 days), some 20 million sooty shearwaters pass through here en route from the North Pacific feeding grounds to breeding sites around New Zealand.

Since the late 19th century,[2] they have driven about 60% of the seabird species from the mainland completely, and during particular dry spells they will cross the mudflats and feast upon the birds on the motus.

That lowering the cat population by some amount would much benefit Christmas and its inhabitants is generally accepted, but the situation is too complex to simply go and eradicate them outright.

The lagoon is famous among sea anglers worldwide for its bonefish (Albula glossodonta), and has been stocked with Oreochromis tilapia to decrease overfishing of marine species.

It is to be noted that the sooty terns for example could sustain occasional collection of effectively all of a season's eggs (over 10 million), if given sufficient time to recover and if cats are absent.

In theory, even egg collecting on a scale that significantly decreases costly food imports could be possible, but not until the cat and rat populations have been brought under control.

Poaching remains a concern; with the population rising and spreading out on Kiritimati, formerly remote bird colonies have become more accessible; the red-tailed tropicbirds and the Sula especially are strongly affected by hunting and disturbance.

Tropicbirds are mainly poached for their feathers, which are used in local arts and handicraft; it would certainly be possible to obtain them from living birds as was routinely done at the height of the Polynesian civilisation.

As noted above, vigorous protection of active nesting grounds from cats by traps and poison, supplemented by shooting, while otherwise leaving them alone to hunt rats may well be the optimal solution.

More recently however, a Massey University study of New Zealand found chromosomal translocations to be increased about threefold on average in veterans who participated in the tests;[51] most of the relevant data remains classified to date.

[1] In general, El Niño conditions will cause seabird populations to drop, taking several years to recover at the present density of predators.

A rising sea level does not appear to be particularly problematic; the increasing flooding of the subsidiary lagoons would provide easily observed forewarning, and might even benefit seabird populations by making the motus less accessible to predators.

It may have been, but probably was not, limited to Kiritimati; while no remains have been found, little fieldwork has been conducted, and judging from the Tuamotu sandpiper's habits, almost all Line Islands would have offered suitable habitat.