Whether it's been going on for ages or not, coastal erosion *is* an ecology issue, considering 90% of the world's population lives in coastal areas.
Plus, many of man's activities affect erosion. Look at a farmer who keeps a treeline along the river running through his property vs. one who cuts trees up to water's edge. Actually, they're hard to find because most farmers are smart enough to leave the treeline. So, sea walls affect erosion, cutting vegetation affects erosion (by removing the plant which hold the earth in place), and (assuming it exists) global warming may certainly affect coastal erosion.
