It doesn't matter that much to me, although it is imporant. It will happen after my life has ended, and it impossible to tell where we (humans) will be in the coming thousands of years.

I'm not sure exactly how much a "tonne" is, but I think it may be approximately 600 lbs. (not 2000, like most americans think of when refering to ton). Either way, it is a huge chunk of land that will make a big impact on shorefront buildings and whatnot. I hope that humans will not be living on earth by that time though, or at least that w will have colonies on other planets (which is another [interesting] topic all together).