Rising Tides and Concerns: Legal Implications of Sea-level Rise

The United Nations has referred to climate change as the defining issue of our time, and we are at a defining moment. The rising sea-level is one such alarming evil of climate change which is unprecedented in scale, steadily attracting global attention. Data derived from satellite radar measurements indicate an accelerating global rise in sea level by 7.5 centimeters (cm) from 1993 to 2017. This is equivalent to approximately 30 cm per century. According to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), the sea-level rise is expected to accelerate even further during the present century. The rise in sea-level at this rate is bound to have a massive impact on the international community as a whole.

More than 70 States, forming about one-third of the states of the international community, are likely to be directly affected by the sea-level rise according to the UN International Law Commission (ILC). In particular, this issue and its implication in international law are of critical importance to low-lying coastal states and small island states. Sea-level rise exposes these areas to risks of partial or total inundation. The small island states are expected to feel the effect of this phenomenon nine times higher than the global average. Thus, the low-lying coastal areas and small island states are on the frontline of climate change and particularly vulnerable to the adverse impact of sea-level rise.


Coastal geography and baselines are used to determine the outer limits of maritime zones of states, as well as maritime boundaries between states. The current international law regime relies on stable geographical conditions. It is tailored to the geographical circumstances of its own time. The advent of sea-level rise threatens the welfare of states and the population residing in these states. As this phenomenon picks up pace rapidly, fundamental changes in international law are on the horizon.

The International Law Association (ILA) explored this topic of sea-level rise in 2012 at the Sofia Conference. It acknowledged “that substantial territorial loss resulting from sea-level rise is an issue that extends beyond baselines and the law of the sea and encompasses consideration at a junction of several parts of international law.” Thereafter, a new Committee on International Law and Sea Level Rise was established. It decided to focus on three main issues: the law of the sea; forced migration and human rights; and issues of statehood and international security. The Committee has released various reports and currently continues to study the phenomenon’s impact on statehood, along with other incidental issues.

The ILC is mandated to “initiate studies and make recommendations to encourage the progressive development of international law and its codification.” Recognizing the growing concerns of sea-level rise, the ILC, in its seventy-first session, in 2019, decided to include the topic “Sea-level rise in international law” in its programme of work. This was based on the recommendation of the Working Group on the long-term programme of work. The Commission also decided to establish an open-ended Study Group on the topic. Thereafter, it received and took note of a joint oral report of the Study Group, containing a road map for 2019 to 2021.

The ILC’s approach to the topic involves the consequences of this phenomenon in three areas: (A.) the law of the sea, (B.) statehood, and (C.) protection of persons affected by sea-level rise.

At the seventy-second session in 2020, the ILC Study Group will focus on the area of sea-level rise concerning the law of the sea. In pursuance of the same, the Commission received examples from states of their practice that could be relevant to sea-level rise by 31st December 2019. The Commission will discuss the questions surrounding statehood and the protection of persons affected by the sea-level rise during the seventy-third session (2021) of the Commission.

a. The Law of the Sea

The sea-level rise is bound to have serious implications on the law of the sea. The United Nations Convention on the Law of the Seas (UNCLOS) plays a crucial role in the determination of maritime zones for the states. The threshold that is used to measure the various maritime zones of a coastal state is called the baseline. From the baselines, different maritime zones are measured, and the outer limits of maritime boundaries are determined. It is also central to the delimitation of maritime boundaries between states, to maintain certainty. However, the increasing sea-level rise brings along with it, an element of uncertainty. With the sea-level rise, the baseline is expected to gradually move landward, ultimately distorting the outer limits of maritime zones. It may call into question the entire structure of the maritime zones under the current law of the sea.

The UNCLOS was formulated, keeping in mind the coastal geography in its own time, and has no remedies for the potential consequences of sea-level rise. The current law of the sea is incapable of coping with the substantial changes in coastal geography caused by a major natural phenomenon such as sea-level rise. To protect states and their maritime entitlements, there needs to be an overhaul in the regime, which adapts to the changing dynamics of the geographical conditions.

b. Statehood

The impact of sea-level rise on states gives rise to fundamental questions regarding the principle of statehood under international law. The criteria for statehood under international law include: (a) a permanent population; (b) a defined territory; (c) government; and (d) capacity to enter into relations with other States. While the concept of creation of statehood is a strongly embedded topic in international law, the extinction of statehood is a topic that has been viewed from distinct standpoints. Some experts believe that the extinction of States must be determined using the same criteria through which the existence of a state is determined. In view of this perspective, the sea-level rise may have the potential to adversely impact states’ claim to statehood under international law. Total inundation of states would make the territory uninhabitable, wiping out the population through forced migration. This could mean that the state would no longer meet the criteria of defined territory with a permanent population, hence taking away its claim to statehood. The myriad of questions surrounding this claim needs to be addressed, and a solution to the same needs to be sought for the sake of future generations.

c. Protection of persons affected by rising sea-level

Various discussions have come to light involving the protection of persons bound to be directly affected due to the sea-level rise. The sea-level rise has the potential to displace large amounts of the population, disrupt their livelihood, and eliminate their means of bare survival.

The duty of states to extend assistance for the protection of human rights of people directly affected by the sea-level rise needs to be re-examined. It is unclear whether the states can take any steps to help their population to remain in situ. Moreover, there is ambiguity regarding the evacuation, relocation, and migration of persons caused by the adverse effects of sea-level rise. International humanitarian law principles need to be strengthened, forming a clear protocol for states, to protect themselves, and other states and persons directly affected by this phenomenon.


The sea-level rise and its tide of challenges call for a re-examination of the current paradigms of international law. The first step to curb the ill-effects of sea-level rise would be to make efforts to curb the phenomenon itself. The international community must come together and impose stringent measures to meet targets set by international environmental agreements, to slow down or reverse the sea-level rise. Major possible actions could include strengthening international cooperation between states and placing an international obligation to extend help to protect persons directly affected by the sea-level rise. Moreover, there is a need to revamp the law of the sea to meet the changing dynamics of coastal geography. The maritime entitlements and statehood of all the states must be preserved at all costs, notwithstanding the impacts of climate change. Meanwhile, the ILC has taken a step in the right direction by identifying the rising concerns surrounding this phenomenon and making it an agenda item for the forthcoming year.