The article cites the often-cited FAO claim [1] that 70% more food production is needed by year 2050. But researchers are now also increasingly agreeing that dietary choices should be considered -- FAO's "70% increase" claim builds on their projections of future human diets.
For a recent example of this alternative view, see Tilman and Clark (2014) [2]. In summary: Current western diets are harmful for the planet and for human health, so let's also consider changing our diets.
[1] http://www.fao.org/news/story/en/item/35571/
[2] www.nature.com/articles/nature13959 behind paywall, but also on SciHub http://sci-hub.cc/10.1038/nature13959
Giving food for free works, but this is a short-term solution. A long-term solution is making all people productive, but this is a hard problem.
It's not true at all. There's plenty of food in the world, there's plenty of hungry people in the world, unfortunately, they don't tend to be in the same places, and food is perishable, and people don't work for free. It's a transportation and economic problem, not a food shortage problem. It'll probably be solved by better ways to produce locally because shipping food to the starving people isn't going to suddenly start working.
My vegan friends claim that this is only true because we waste so much food/water to feed livestock for meat.
Even if thats not true, humans waste a lot of food. Hell, my local supermarket throws out enough food each day to feed me for a month. (Ok ok not really true because it wouldn't last a month, but quantity-wise...)