Talk-Polywell.org

Up until about the end of 2004, there was little change in the rate of sea level rise. Since then the rise has slowed down. The average (dark blue line) does not stray far from the trend (black line) up until 1994. Since then, it is well below the projected trend (gray line). We were supposed to be seeing some kind of big acceleration in the sea level rise caused by increased CO2. Instead, we are seeing a decrease in the rate of sea level rise. So the first claim, that increasing CO2 will cause increased rates of sea level rise, is not supported by the evidence.

Regarding atolls and sea level rise, the most important fact was discovered by none other than Charles Darwin. He realized that coral atolls essentially “float” on the surface of the sea. When the sea rises, the atoll rises with it. They are not solid, like a rock island. They are a pile of sand and rubble. There is always material added and material being lost. Atolls exist in a delicate balance between new sand and coral rubble being added from the reef, and atoll sand and rubble being eroded by wind and wave back into the sea or into the lagoon. As sea level rises, the balance tips in favor of sand and rubble being added to the atoll. The result is that the atoll rises with the sea level.

Darwin’s discovery also explained why coral atolls occur in rings as in Fig. 1 above. They started as a circular inshore coral reef around a volcanic rock island. As the sea level rose, flooding more and more of the island, the coral grew upwards. Eventually the island was drowned by the rising sea levels, and all that is left is the ring of reef and coral atolls.

Why don’t we see atolls getting fifty feet high? Wind erosion keeps atolls from getting too tall. Wind increases rapidly with distance above the ocean. The atolls simply cannot get taller. The sand at that elevation is blown away as fast as it is added. That’s why all atolls are so low-lying.

When the sea level rises, wind erosion decreases. The coral itself continues to grow upwards to match the sea level rise. Because the coral continues to flourish, the flow of sand and rubble onto the atoll continues, and with reduced wind erosion the atoll height increases by the amount of the sea level rise.

Since (as Darwin showed) atolls float up with the sea level, the idea that they will be buried by sea level rises is totally unfounded. Despite never being more than a few metres tall, hey have survived a sea level rise of up to three hundred plus feet (call it a hundred metres) within the last twenty thousand years. Historically they have floated up higher than the peaks of drowned mountains.

So the third claim is not true either. Atolls are created by sea level rise, not destroyed by sea level rise.