Diego Garcia is suffering the same fate as other islands in the Indian Ocean: rapidly accelerating reef loss due to ocean acidification/warming. According to Edis, over 95 percent of Diego Garcia’s seaward reefs have been killed due to elevated seawater temperatures. While this does not create any immediate operational impacts, it certainly impacts the long term ability of the DGAR to be able to sustain a large population.
The issue of sea level rise is probably more acute; indeed, one of the reason why the 2008 UK House of Lords deemed that resettlement of the atoll was not possible coastal erosion of the Northwest Shore . On average, DGAR has roughly is four feet above sea level (most areas do not exceed 6.5 feet) and contains ten square miles of dry land. The initial problems will be salt water intrusion into fresh water resources, storm surges, and intermittent tidal flooding, all will vary in severity. The U.S. Navy currently has a forty-person construction detachment installing imported rocks to prevent further encroachment from the sea.
For the United States and the UK this creates two complications. First, the danger of inundation creates issues for engineers who will have to erect systems such as seawalls and barriers to protect critical base structures. These systems will be quite expensive since all the materials have to be imported and the DOD will need to make the case that the operational benefits outweigh the costs of making improvements to leased real estate that has a uncertain political future.
The second issue with loss of arable space is that it deprives the United States and the UK of a future bargaining chip should it wish to grant some number of the Chagosians return rights so they might engage in agricultural or aquaculture activities in the very large lagoon. The rich fisheries in DGAR’s lagoon holds the promise of viable economic activity should some people wish to return. Similarly, the use of employing persons as labor to support base operations and supply local fruits and vegetables versus relying upon imported contractors—mostly from the Philippines—to provide base services is something worthy of consideration. For over seventy-five years, DOD has been able to successfully operate in foreign countries because it makes use of local suppliers and host nation labor. That preference for local labor helps to solidify relationships between DOD and the host nation. For it to work in this case any “returnees” would need to be able to perform necessary support tasks or be trainable.
There has been a significant domestic and international litigation questioning the legitimacy of the British mandate over DGAR and ways in which the UK managed the removal of Chagos islanders in 1971.
Actions by Former Residents and Descendants
In 2011–2012 the 1,786 Chagos descendants living in the UK pursued an action in the European Court of Human Rights (ECHR) , claiming that they had been denied their human rights because of their “callous and shameful” removal from DGAR and lack due process. In short opinion, the Court ruled in 2012 that since the descendants of the islanders had received modest compensation and renounced their claims in writing, their claims were disallowed.
Legal challenges were then brought in the British Courts over the removal of the former residents 1971 to make way for the U.S. base. They first petitioned the House of Lords. That petition was unsuccessful because the Lords, as noted above, felt the area could not sustain large populations and that the former residents had been fairly treated. The Lords decision was appealed to UK Supreme Court which dismissed the appeal by a 3-2 margin in 2016. For the time being at least, the domestic legal question of whether the UK government had complied with its own laws/procedures is in check; however, but a 3-2 decision does inspire confidence that future challenges won’t be mounted.
Newer International Legal Challenges by Mauritius and the UN
UK Marine Protected Area Invalidated by UNCLOS Panel.
The second avenue of attack against the British (and by extension the United States) possession of the Chagos has come from Mauritius. As in the author’s September 2017 legal assessment , Mauritius pursued an action in 2015 in an UNCLOS international arbitral tribunal to set aside the UK’s declaration of large areas of the Chagos Archipelago to be Marine Protected Area (MPA). Mauritius’ contention was that UK’s MPA detachment of the BIOT from the Dependency of Mauritius gave Mauritius fishing rights in the waters of Chagos and that the MPA could not encroach on those rights. At the time the BIOT was detached from Mauritius, the transfer documents (Lancaster House Undertakings) promised Mauritius some form of preferential” treatment to resources of the Chagos for fishing and other purposes. Given that the UK had repeatedly ratified the Lancaster House Undertakings through its actions, the Tribunal unanimously ruled in Mauritius’ favor that the UK could not unilaterally restrict Mauritius’ fisheries rights by establishing a MPA without prior consultation.