[Redcloak]

Are we sure that the sea is really rising? I don't see how one can arbitrarily rule out the possibility that Australia is sinking.

[Deguello]

Yes, I remember that episode on Gilligan's Island.

Gilligan have been moving the Professor's tide marking stick over time so as to tie up his crab traps in deeper water. Professor announced that the Island was sinking. Ginger had such a fit that I thought (I was ten then) she was going to come out that dress she wears.

[Dan Day]

Are we sure that the sea is really rising? I don't see how one can arbitrarily rule out the possibility that Australia is sinking.

You may be joking, but that's not such a ridiculous possibility.

The measured change is about 1 mm per year -- in constrast, continental drift causes the continents on each side of the Atlantic to slide apart by about 25 mm per year.

If entire continents can move laterally by 25 mm per year, it's not unreasonable to think that an isolated one (Australia) might rise or sink by 1/25th of that amount in the same time.

[jeremiah]

Good point, or that the area where the mark was made has shifted.

[cogitator]

I don't see how one can arbitrarily rule out the possibility that Australia is sinking.

The researchers used the position of a nearby fossil shell bed to address this.