Sea Level and the Coast
Sea levels are rising at present at approximately 4 cm per year. This is faster than in recorded geological times.
In the last 150,000 years the coast has seen three major changes in sea level. These have resulted from the earth warming and then cooling to a period in which much of the earth was covered in ice.
At approximately 150,000 years ago the earth was experiencing an interglacial period. The atmosphere was about 1 to 2 degrees hotter and so the sea level was approximately 5-9 m higher than present. Wave action began to carve rock platforms on the hill sides and ridges newly exposed to the waves.
At the next glacial period 26,000 to 20,000 years ago the sea level fell and was approxiamtely 120m lower of the present coast. This level platforms exposed as benches on some cliff lines.
Approximately 12,000 years ago the warming climate caused the ice sheets to melt again and the sea level to rise. It reached this level approxiamtely 6,000 years ago and new rock platforms were carved.