Sea Level Rise and Shifting Maritime Jurisdictional Limits

1
Sea Level Rise and Shifting Maritime
Jurisdictional Limits
Clive Schofield Australian National Centre for
Ocean Resources and Security (ANCORS)
2
Sea Level Rise

• IPCCs estimated range of sea level rise
  0.38-0.59m by the end of the century?
• Growing consensus that this estimate is overly
  conservative
• Great uncertainty over the critical questions of
  how much and how quickly?

3
Maritime Jurisdictions Zones
Territorial Sea Baseline
Internal waters
200 M
12 M
12 M
Sea Level
Shelf
Upper
Plateu
Slope
or
Lower
Terrace
Deep
Rise
Slope
Ocean
4
Migrating Baselines Shifting Limits

• Maritime jurisdictional limits measured from
  baselines
• Predominantly normal baselines, low-water line
  baselines
• Traditional interpretation ambulatory baselines
  and consequently shifting limits
• Coastlines dynamic low water line susceptible
  to change
• As normal baselines move, the limits drawn from
  them also shift
• Not a new phenomenon
• As sea level rises so the low-water line migrates
  inland
• Dramatic horizontal shifts to normal baselines
  possible from slight changes to sea level
  vertically

5
Impacts on Islands

• Sea level rise/shifting baselines will also
  impact on the classification of insular features
• Most common normal baseline used, Lowest
  Astronomical Tide (LAT) a very low low water
  line
• Critical basepoints may be unstable or ephemeral
  insular features
• Vulnerable to sea level rise leading to
  downgrading of islands to mere rocks or low-tide
  elevations
• Impact on capacity to generate claims to maritime
  jurisdiction

6
Implications

• Implications for
• Extent and limits of maritime claims
• Enforcement issues
• Delimitation of maritime boundaries
• Loss of jurisdiction over vital marine resources
• Jurisdictional uncertainty
• Potential for conflict

7
Potential Responses

• Fix normal baselines physically
• Can key basepoints be preserved through sea
  defences, building-up and/or reclamation?
• Long tradition and an option for critical
  basepoints but unrealistic for long coastlines?
• Fix normal baselines legally
• Fix the limits of maritime zones

8
Okinotorishima Maritime Claims
9
Okinotorishima
10
Okinotorishima
11

• Physical defences unrealistic for long
  coastlines?

12
Fix Normal Baselines Legally

• Choice of chart depicting normal baseline left up
  to the coastal State (LOSC, Article 5)
• Chart the legal document
• Can a coastal State therefore choose a chart that
  is advantageous to it?
• What if there is a difference between the low
  water line shown on the chart and reality?
• The drafters of the Convention did not anticipate
  sea level rise
• BUT Ambulatory baselines may be fixed with
  straight baselines on unstable coasts
• Connection to the low water line still required

13
Fixing Limits and Boundaries

• Once agreed maritime boundaries remain fixed even
  though the baselines used to construct them may
  regress
• What if the territory in question disappears
  entirely?
• The outer limits of the continental shelf may
  also be fixed as final and binding
• Fix (declare) maritime limits
• Provides the advantage of certainty and the
  preservation of existing maritime claims
• BUT Increasing tension between fixed limit and
  receding or disappearing normal baseline it is
  measured from