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

2. Sea Level Rise
IPCC’s estimated range of sea level rise: m 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
(Extended
Continental Shelf)
The
Area
Continental Shelf
Sea-bed, Subsoil, Sedentary Species
Territorial Sea Baseline
Exclusive
Economic Zone (EEZ)
Water Column,
Sea-bed, Subsoil
High Sea
Internal waters
Contiguous
zone
12 M
200 M
Territorial
sea
12 M
© 2008
Sea Level
Shelf
Upper
Plateu
Slope or
Terrace
Lower
Rise
Deep
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. Critical basepoints may be unstable or ephemeral insular features
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 for: Implications
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. Fix normal baselines physically
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