Regarding the ice melting situation, there is more information about the displacement issue in a
Google Answer.
As for Hydrogen Fuel Cells, there is a lot of arguements around how effective they will actually be.
Just do a
quick Google search and you'll find plenty to argue about in this area.
In the end, no matter the solution, it's going to cost us a lot of money if we want to survive through all of our problems. The unfortunate thing is that those who actually have power over these things may not be willing to pay that money.