Helga Law Journal - 01.01.2021, Page 59

Helga Law Journal Vol. 1, 2021
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Dr. Snjólaug Árnadóttir
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baselines rely on. If basepoints are on elevated peaks they may withstand coastal
erosion and sea level rise, effectively making coastlines more heavily indented but
without shifting the location of straight baselines or closing lines.
UNCLOS does not explicitly state that baselines and derived outer limits must
fluctuate in accordance with changing coastlines. Most commentators adhere to
the theory of ambulatory baselines and this is clearly reflected in the work of the
ILA Baselines Committee and the ILA Committee on International Law and Sea
Level Rise.49 However, Purcell argues that baselines do not necessarily fluctuate
with changing coastlines because the rules regarding the extent of baselines are
separate from the entitlement to a lawfully established claim.50 She seems to view
the rules on maritime limits as constitutive and not requiring ongoing adherence.
The theory of ambulatory baselines has been derived from two exceptions,
which are enshrined in UNCLOS articles 7(2) and 76(9). The theory provides that
‘baselines and boundaries generated from them are “ambulatory” […] that is, the
baselines – and therefore the boundaries – adjust themselves to a changing
coastline’.51 UNCLOS article 7(2) provides that straight baselines at highly unstable
deltaic coastlines remain effective ‘notwithstanding subsequent regression of the
low-water line […] until changed by the coastal State in accordance with this
Convention’. UNCLOS article 76(8) allows States to establish ‘final and binding’
outer limits to the continental shelf beyond 200 nm and these are permanently
described in accordance with UNCLOS article 76(9). This stability is only afforded
to straight baselines and outer continental shelf limits in very specific
circumstances and it is contingent on different procedural requirements.
Therefore, the general rule is that all limits fluctuate in accordance with changing
coastal geography. Straight baselines, and derived outer limits, can remain
enforceable as coastlines change but only if the instability is a result of a delta and
other natural conditions or if the limits conform to information submitted to the
UNSG, as per UNCLOS article 16. Similarly, continental shelf limits can remain
stable but only if established on the basis of recommendations of the Commission
on the Limits of the Continental Shelf (CLCS) and if the limits have been
permanently described before the UNSG.52
Many States fail to submit relevant data to the UNSG. Some States adopt
legislation concerning their limits but according to the UN Division for Ocean
Affairs and the Law of the Sea (DOALOS), such acts do not suffice to satisfy
obligations arising under UNCLOS articles 16(2), 47(9), 75(2), 76(9) and 84(2):
‘The mere existence or adoption of national legislation or the registration of a
maritime boundary delimitation treaty […] even if these instruments contain charts
and/or lists, cannot be interpreted as an act of deposit with the [UNSG] under the

49 ILA Baselines Committee ‘Conference Report Sofia 2012’ (ILA 2012) 31; ILA Committee on
International Law and Sea Level Rise ‘Sydney Conference’ (ILA 2018) 11-12.
50 Kate Purcell, Geographical Change and the Law of the Sea (Oxford University Press 2019) 12-13.
51 David D Caron, (n 22) 2.
52 See UNCLOS articles 76(8) and (9).
‘any appreciable extent’.41 States must take positive action to activate the right to
employ straight or archipelagic baselines and these baselines must be clearly
defined by relevant coastal States.
Outer maritime limits to maritime zones are generally at a fixed distance from
baselines and can, consequently, be identified by reference to baselines. However,
the outer limits of the continental shelf can be determined by reference to the
natural prolongation of the continental margin where it extends beyond 200 nm.42
UNCLOS article 16 provides that straight baselines, closing lines around bays and
rivers, and the outer limits derived therefrom ‘shall be shown on charts of a scale
or scales adequate for ascertaining their position. Alternatively, a list of
geographical coordinates of points, specifying the geodetic datum, may be
substituted’. Moreover, coastal States must duly publicise their charts or lists of
geographical coordinates and deposit copies with the UN Secretary-General
(UNSG).43 The same applies to archipelagic baselines,44 and articles 75 and 84
further confirm that these obligations extend to the outer limits of the exclusive
economic zone and the continental shelf.
The impacts of climate change on maritime entitlements are most severe when
they change the status of coastal features. A low-tide elevation may only be used
to form the baseline for measuring the breadth of the territorial sea if it is within
12 nm from the mainland or an island.45 Furthermore, islands that become
uninhabitable or incapable of sustaining economic life because of inundation will
no longer generate an exclusive economic zone or a continental shelf, i.e. if they
are reduced to rocks as per UNCLOS article 121(3), and if a rock is completely
submerged it also loses all entitlements to a territorial sea.46 Similarly, States can
lose the capacity to qualify as archipelagic States and, consequently, the right to
rely on straight archipelagic baselines.47
The gradient of the coast can be an important factor for evaluating the
consequences of coastal changes for maritime entitlements. ‘[W]here the coastline
is gently shelving, even relatively slight changes in sea level vertically can result in
significant shifts in the location of the low-water line horizontally and this, in turn,
can have significant impacts on the spatial extent of national maritime claims.’48
Straight baselines, archipelagic baselines and closing lines do not have the same
direct correlation to the low-water line as normal baselines; the mean low-water
line can undergo substantial changes without affecting the furthest seaward
extensions, which the basepoints for closing lines, archipelagic and straight

41 UNCLOS articles 7 and 47.
42 See section II.B. and UNCLOS article 76.
43 UNCLOS article 16.
44 See UNCLOS articles 47(8) and (9).
45 UNCLOS article 13.
46 Alfred H A Soons (n 27) 216-217.
47 See UNCLOS article 47.
48 Clive Schofield and Robin Warner, Climate change and the oceans gauging the legal and policy
currents in the Asia Pacific and beyond (Edward Elgar Pub 2012) 136.