Might I suggest...

It's quite true that the world is warming up from its latest long ice age, and soon (perhaps within a few hundred years) much of its land surface will be inundated.  Students of geology know that this is something that the earth does periodically over hundreds of thousands and millions of years. There have been ages when the earth was completely frozen over, like a giant snowball, and other ages when all the ice in both polar caps was melted and the land surface of the planet was reduced by as much as a half.  There is concern at present among all the countries of earth to halt or reverse the present warming trend, it being supposed that there is nothing to be done to preserve the open land mass from inundation by the planet's oceans if it continues.  This, if I may say so, is an unnecessarily pessimistic view of the matter.

For what if, as the water in the polar caps melts and the oceans rise, it were diverted off the planet, by immense pumps and siphons, into vast artificial satellite reservoirs, in orbit around the earth and presumably globular in form, where it might be kept safely, and perhaps used in hydroponics systems to supplement the world's food supply--until the inevitable recurrence of another ice age, and the reconstitution of the polar ice caps, will require returning it to earth?

The point being that it is the nature of the earth as we know it, over long aeons, to alternate ages of relative warmth with ages of frigidity; and rather than try to fix one narrow temperature range and try to make the earth adhere to it (which would be futile, on the evidence of several billion years of geological history), it seems to me more sensible to try to find ways to adapt to these long periods of climate fluctuation, and, with the help of modern science and technology, to attempt to moderate them.