New agricultural technique involving large-scale agriculture in urban areas!

With the increase in population globally, farm lands are getting converted to flats and apartments. Does it in anyway help agriculture. How are we going to fulfil the need for food supply?

I have heard of terrace farming in Japan where most of their farm lands are made on terraces. Especially they grow rice on terrace that also uses less water for irrigation.

That way, this one also looked impressive. What is it? It’s called as Vertical Farming.
Web Definition: Vertical farming is a proposed agricultural technique involving large-scale agriculture in urban high-rises or "farm scrapers". Using recycled resources and greenhouse methods such as hydroponics, these buildings would produce fruit, vegetables, edible mushrooms and algae year-round.

+ve’s: Vertical farms could significantly alleviate climate change produced by excess atmospheric carbon.

-ve’s: But costs of the additional energy needed for artificial lighting, heating and other vertical farming operations might outweigh the benefit. Also financial viability may be a concern for today for adopting vertical farming largely.