The sea level changes all every day, and at different rates. You could come up with 1000 BS reasons why, such as the one Big Al The Gorebull Warmers Pal tried to lay on the Philipene people a couple years ago.
The Philipene geologists had been studying the receding shoreline in one area for very many years, and had discovered that the land was simply sinking due to a groundwater problem.
All of a sudden, the Gorebull Express flew into town, called a town meeting, and scared the crap out of the locals, who'd never seen anyone so fat or loud. He gave his bull in heat impression, told 'em there's icebergs on the way, they're gonna sink anytime now, and when they see the icebergs in the harbor, RUN!
Naturaly, the geologists who'd been studying and dealing with this natural phenomema for decades weren't amused, but I sure was!
Nice answer. Thanks for the effort.