Coastal Vulnerability to Climate Change

by

David A.Y. SmithSmith Warner International

Profile of the Caribbean and Profile of the Caribbean and Coastal AreasCoastal Areas

Greater Antilles/Lesser Antilles – based on location and geological origin

All are islands with high coastline to area ratios, and are therefore particularly vulnerable to coastal hazards.

Differing levels of risk across the region

Coastal Hazards in the Coastal Hazards in the CaribbeanCaribbean

Greater Antilles

(Cuba, Jamaica, Hispañola, Puerto Rico)

•Hurricanes

•Floods

•Earthquakes

•Tsunami

Lesser Antilles

(St. Maarten to Trinidad)

•Hurricanes

•Volcanic Eruptions (Ash fallout)

•Earthquakes

•Tsunami

Over 8,000 lives lost in the Caribbean over past 30 years due to natural disasters.

Damage from HurricanesDamage from HurricanesOccurs primarily from:

– Hurricane waves; – Beach scour and;– Storm surge.

Spatial Distribution of Spatial Distribution of Hurricanes in the RegionHurricanes in the Region

Hurricane WavesHurricane Waves Deep water waves resulting from

hurricanes can be very damaging. Estimates of extreme (i.e. design) wave heights made throughout the region are summarized following:Island 1 in 50 year

Return period (m)

1 in 100 year (m)

Jamaica 7.6 8.6

Antigua 13.3 14.9

Grenada 8.1 9.6

Hurricane Waves (cont’d)Hurricane Waves (cont’d)

Changes result from interactions between the waves and the seabed

At the shoreline, they can be very damaging, breaking out infrastructure and eroding shorelines.

These deep water waves change in height as they travel in to shallower water.

Beach ScourBeach Scour In a storm, high

wave energy often results in severe erosion of the beach and/or shoreline.

Erosion may reach up to 20-30m inland, and can totally wipe out beach areas and adjacent infrastructure.

Beach Scour (cont’d)Beach Scour (cont’d) Erosion is

exacerbated where there are buildings (i.e. vertical walls) in the wave run-up zone.

Shore protection methods must be carefully designed so as not to negatively impact adjacent shoreline areas.

Components of Storm Components of Storm SurgeSurge

Components of Storm SurgeComponents of Storm Surge

Storm Surge, Roseau, Dominica, Hurricane Lenny

High storm waves, Cayman,Hurricane Ivan

Examples of Storm Surge Examples of Storm Surge

Impact of Water Level Impact of Water Level ChangesChanges

Based on UN-IPCC observations and Circulation Model outputs, rates of sea level rise in the Caribbean will be 5mm/year for next 100 years;

Rate will neither be uniform nor constant due to site-specific reasons (e.g. crustal emergence and/or submergence);

This rate is 2 times higher than rate for the past 100 years;

Low-lying beaches, terraces and plains will be more vulnerable to storm events as a result of this rise.

Kingston VulnerabilityKingston Vulnerability

Source: NEPA

Some Issues for ConcernSome Issues for Concern•Large percentage of Jamaica’s population (approx. 25%) and critical infrastructure is concentrated near to the coastline.

•There is some evidence, when the past 115 years of hurricane data is examined, that we are in a cycle with an increasing number of storms.

Data Collection/GapsData Collection/Gaps Water levels have been collected under

the aegis of the OAS at a number of locations across the Caribbean.

Many of these stations have fallen into disrepair and have not been maintained.

Long-term records of water levels must be collected if we are to assess our own levels of risk and vulnerability to sea level rise.

What are the present plans to commence or mainstream data collection?

Data Collection/Gaps Data Collection/Gaps (cont’d)(cont’d)

What are the rates of accretion or erosion at our beaches in Jamaica?

A programme of beach profile monitoring of beaches and/or shorelines at key points around the shoreline of Jamaica would assist in identifying a problem (or not).

Given the importance of the tourism sector to our national economy, monitoring of shoreline change is required.

Again, what are the present plans to commence or mainstream data collection?

Tsunami: another source of Tsunami: another source of riskrisk

More a problem in the Lesser Antilles

Caused by ocean centred earthquakes, or volcanic eruptions.

Greatest risk presently posed by “Kick ‘em Jenny”

SeaBeam image of Kick 'em Jenny constructed from measurements taken from the NOAA Research Vessel Ronald H. Brown on March 12 2002.

Tsunamis in the Tsunamis in the Caribbean: Historical Caribbean: Historical

AccountAccountDates and Locations of Tsunami

Date Location Comment 1897-Nov-29 West Indies Large tsunami at Montserrat 1907-Jan-14 Jamaica Tsunami generated, main damage at Kingston 1918-Oct-11 Puerto Rico Tsunami caused fatalities and damage at Point

Borinquen and Aguadilla; also damage at Mayaguez

1946-Aug Dominican Republic

Town of Matanzas badly damaged and abandoned; more than 100 persons killed; minor damage on coast of Haiti

1953-May-31 Dominican Republic

Very slight tsunami; amplitude 0.2 ft at Puerto Plata

1955-Jan-18 Venezuela Tsunami caused damage at La Vela, Venezuela