This is hyperbolic. The article was about ice in Greenland, not about the habitability of the planet. Yes, the planet is becoming less hospitable, but we aren't talking about an extension level event for humanity yet.
No scientific arguments exist that would support this claim. Some land area might be lost, but other areas will become accessible through warming (think Siberia, Greenland, Canada).
On the contrary, we should expect the planet to become more hospitable, with higher crop yields, more plants and better average climate for human life on land mass.
The human population increase is the real problem.
Moreover, in many places of the world food is produced inefficiently, so there is a lot of additional food that can be grown even without increasing land use.
(currently there is enough food grown to feed everyone, it is logistics problem now)