AIACC Asia Regional WorkshopSession C2: Water Resources,

Watersheds, Coasts (Bangkok, 26.3.03)

Vulnerability and Adaptive Capacity in the Archipelagoes

of the South Pacific

Patrick D. Nunn

The University of the South Pacific

Organisation of this Talk

• Overview of the South Pacific archipelagoes

• Water resources – vulnerability and adaptive capacity

• Watersheds - vulnerability and adaptive capacity

• Coasts - vulnerability and adaptive capacity

• Future work/prospects

Part 1:

Overview of the South Pacific archipelagoes

Overview of South Pacific island vulnerability

• Comparatively large ratios of coast length to land area.

• Comparatively remote and difficult of access.

• Comparatively high dependence of people on locally available food sources.

Overview of South Pacific island adaptive capacity

• Large area of highly vulnerable coastal lowland.

• Comparative smallness of land areas limits within-island relocation.

• Most practical environmental decision-making is at community level.

• Lifestyle options limited.

Part 2:

Water resources – vulnerability and adaptive

capacity

Pollution

Vulnerability –

Increasing demands (agricultural, urban, waste, industrial, marine)

Pollution

Adaptive capacity –

More effective environmental legislation, improved public awareness

Shortage

• Vulnerability –– Natural droughts– Infrastructural

maintenance

Shortage

• Adaptive capacity –– Improved public

awareness– Improved forecasting– Improved

management

Part 3:

Watersheds – vulnerability and adaptive capacity

Natural landscape changeVulnerability –

Natural processes, exacerbated by changes in climate and climate extremes

Natural landscape changeAdaptive capacity –

Many settlements can move fairly easily, hard engineering solutions often prohibitively costly.

Human-induced land degradation

Vulnerability – inland populations increasing and likely to increase further as coastal populations are displaced. Many inland landscapes degraded from millennia of agricultural use and burning.

Human-induced land degradation

Adaptive capacity – low in many island countries because island land areas are small. Crop strains more suited to upland than lowland areas, and more tolerant of warmer wetter conditions need to be developed.

Part 4:

Coasts – vulnerability and adaptive capacity

Melanesia, 1860s?

Shoreline protection

0

5

10

-5

-10

-151900 1920 1940 1960 1980

Years AD

C mHO NO LULU TIDE-G AUG E REC O R D

Coasts - vulnerability

• Low-lying• Unconsolidated• Permeable• Subject to storms• Locations of most

settlements, most infrastructure, most revenue-generating enterprises (including tourism)

Consequence of 20th-century sea-level rise:

inundation and salinisation of coastal

lowlands.

Bruun Rule

Consequence of 20th-century sea-

level rise: shoreline erosion along

sandy coastlines.

On-site adaptation where possible

Out-migration where on-site adaptation impossible

Coastal vulnerability – the seawall mindset

• Most government and community-level decision makers believe in remedying short-term problems rather than addressing the likely long-term effects.

Coastal vulnerability – the seawall mindset

• Most long-term solutions are being driven by NGOs although governments commonly pay lip-service to such sustainable solutions.

Coasts – adaptive capacity

Accommodation

Coasts – adaptive capacity

Protection

Coasts – adaptive capacity

Retreat inland

Coasts – adaptive capacity

Retreat upslope

Part 5:

Future work/prospects

120

100

80

60

40

20

0

1800 1900 2000 2100

Cm

Year AD

Extrapolated level

1992a Low (+19 cm )

1992a Best (+51 cm )

1992a H igh (+91 cm )Sea-Level Rise, AD 1800-2100

0 10km

N

D ensely-popu latedareas

TO N G ATA P U ISLA N D , K IN G D O M O F TO N G A

0 10km

N

Land area less than5 m above sea leve l

D ensely-popu latedareas

TO N G ATA P U ISLA N D , K IN G D O M O F TO N G A

• Probable sea-level rise over the next 100 years will see some parts of the Pacific disappear, many others significantly reduced in habitable area.

• The geography of the Indo-Pacific region will change.

Sea-level rise

In atoll nations, the effects of future sea-level rise are certain to produce environmental refugees.

Coral-reef death

• Increased ocean-surface temperatures over the next 100 years will kill many of the world’s coral reefs.

Aims of AIACC Project (S)IS09

• Improve models for vulnerability and adaptation assessment in the Pacific Islands region.

• Develop the capacity of Pacific Island nations to plan more effectively for future climate change.

• Develop and trial methods of assessment which are transferable to other island regions.