I've looked at the article, and there are many things that don't make sense to me. Like why a 2050 world population of 8.6 billion (or 9.2 billion, both numbers are thrown out in the article), an increase of 50%, would need 1 billion hectares of new farmland, an increase of 125 % over the present 800 million hectares.
Or why we can't just convert the zillions of acres devoted to raising and feeding cattle, pigs, etc. (a highly inefficient process) to producing grains for human use.
Or why we're worrying about feeding a growing population at all, when such worries have proven unfounded over and over in the 150 years since Malthus.
If I was really worried about such problems, I would concentrate on raising plankton and algae. Much more efficient than this boondoggle.
There's an interesting and informative cost analysis of this idea here:
AustinContrarian: Very, very expensive farmland (updated)
There's also an interesting discussion at slashdot:
Slashdot | Vertical Farming