Hope

You may think we are coming to a dead end.

But, unlike my usual self, I am less pessimistic on this matter.

To be specific, although the efficiency of photosynthesis seems abysmal, it also implies that an improvement to 10% would mean a doubling of food production.

In fact, a few simple figures could shed light on further areas on improvement:

• The efficiency for conversion of photosynthetically active radiation (wavelengths from 400 to 700 nm) to chemical energy or biomass is 25%.
• Only 45% of the actual sunlight is photosynthetically active.
• Plant absorbs only 25 to 50% of the incoming sunlight for photosynthesis. (The other is dissipated by reflection and respiration requirements of the plant itself.)
  

You see what we are getting at ? On the first glance, item 1 seems an attractive target. However, it is indeed quite fixed because evolution in the past millions of years have ensured the efficiency of chlorophyll and the molecular machinery.

Item 2 appears to be fixed - you cannot change the spectrum of sunlight, but we can modified the structure (and therefore absorption spectrum) of chlorophyll.

Of course, it seems more easy to make the plant reflect less light.

But, the first thing we have to accept is: We are talking about genetically modified food.