Indeed, looking at Petit Martinique from the air shows what you don’t see on the southern side of the fringing reef. You can see the reef below water, but you don’t see the waves breaking there as you do in front of St. Vincent. While the reef of Petit Martinique is still getting protection from bigger storm waves (waves break ~ when Wave Height = Depth of Reef Tops), their fringing reefs are not protecting it from the daily disaster.
Now consider that this daily disaster is playing out just behind Dexter’s town in the village of Windward, where their ancestors’ graves are being washed into the sea (see image above). It’s also happening in coastal towns and villages throughout Grenada and the Grenadines; the windward isles of the eastern Caribbean ecoregion; throughout the Caribbean; throughout the tropical Atlantic; throughout the tropics globally.
These Coral Reefs Are the Wall Between Us and Rising Seas
Conservationists often say that we are going to have to be proactive and smart about how we respond to climate change, because it will be impossible and too expensive to build a wall around whole towns, cities or islands (except, of course, places like New York City). But consider for a moment that in fact these fringing coral reefs are the wall — the natural infrastructure, sometimes 30, 60 or even hundreds of feet high — that rings villages, cities and whole islands. Think for one moment about the cost of erecting such a wall; and the benefits lost without it.
To save them, we are going to have to act fast and be much more proactive. On Petit Martinique, they are already heavily defending their shores — often house by house — with hastily erected breakwaters and gabions. Each small gray shore defense that goes in increases erosion just a little downshore and requires another gray solution in that spot. In Dexter’s town, they are pushing to get a whole breakwater wall — a project that will cost EC$3.5M at a minimum.
I can appreciate why they need to act now, but all of these fixes will be temporary. As sea levels rise and (far more importantly) if the barrier reefs continue to break down, then ever more wave energy will make their temporary solutions ineffective. These likelihoods are not currently accounted for in the engineering and design models for breakwaters (or it would become clear how unviable they might be).