You note that Egypt's population has “more than tripled in the past 50 years and is expected to surpass 150 million by 2050” (Nature 544, S14–S16; 2017). This rate of population growth would seem to be unsustainable, given that only 5% of Egypt's land is suitable for cultivation and that almost all of that land is already being farmed. Even with this intensive land use, the country still imports 40% of its food. I suggest that the problem is not so much that Egypt produces too little food, but rather that it is home to too many people.

Plans for closing the gap between food production and consumption — including drilling for fresh water under the Sahara and desalinating sea water — are impractical and prohibitively expensive (see go.nature.com/2ryeayb and go.nature.com/2qkacsw). In my view, more investment to reduce the birth rate is a better path to a sustainable balance between food production and consumption.