aiacc asia regional workshop session c2: water resources, watersheds, coasts (bangkok, 26.3.03)...
TRANSCRIPT
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.