I haven't given much thought to the Hawkings quote. I'm an optimist. Where others see problems, I see opportunities.
Desalinization is unpopular now because of the cost, yet people will pay $2 a bottle for spring water even though water is available free from their tap. As we become more populous, and the need for more water becomes evident, the costs will likely be worth it. New technologies will lower that cost significantly if the future.
Aircraft carriers generate their own fresh water through desalinization of sea water. They provide sufficient water for a crew of 7,000, plus the launching of aircraft and the operation of a variety of steam-powered equipment. Submarines do likewise, on a smaller scale.
The global warming/ice melt was tongue in cheek, which is why I used the little smiley thingy. As has been pointed out before, no one knows what the effects of global warming will be. If it gets too warm, the dinosaurs will probably want their land back, and we'll have to move anyway. After all, they were here first!