IVETTE FELICIANO:

Marcelis says one important part of their work is developing techniques that can be replicated anywhere, even in arid climates like the Middle East or sub-Saharan Africa. The United Nations estimates as the world's population grows, global food demand will rise 70 percent by 2050, even as the amount of water and farmable land shrinks due to the global warming.

The Netherlands is already doing its part to feed the world. Propelled by indoor farming, it's become the second biggest food exporter in the world, accounting for nearly 90 billion dollars last year. This is all the more astounding given that the Netherlands is less than one-percent the size of the United States, the world's number one food exporter, where indoor farming is also gaining a foothold.

Here in Kennett Township, Pennsylvania, mushroom growers have been practicing indoor farming for over a hundred years, and today produce half the U.S. mushroom crop.

An hour outside Philadelphia, this small community of eight thousand people harvests half a billion pounds of mushrooms every year — all of it indoors and at a low cost of about one dollar per pound.