Plants are great at using sunlight to convert CO2 — along with water and some soil nutrients — into food. However, photosynthesis is confused by oxygen in the air, and plants have a costly system for dealing with the problem: photorespiration. That means less food on the table for us. Luckily, scientists at the University of Illinois and the U.S. Department of Agriculture Agricultural Research Service report in the journal Science that they have found a photorespiratory shortcut that boosts productivity by 40%. [perfectpullquote align=”right” bordertop=”false” cite=”” link=”” color=”” class=”” size=”24″]…meeting the 21st century’s rapidly expanding food demands…[/perfectpullquote]
Lead investigator, Illinois Prof. Donald Ort, said, “We could feed up to 200 million additional people with the calories lost to photorespiration in the Midwestern U.S. each year,” adding that “reclaiming even a portion of these calories across the world would go a long way to meeting the 21st century’s rapidly expanding food demands — driven by population growth and more affluent high-calorie diets.”
Paradoxically, plants produce the very pollutant that requires photorespiration: oxygen. Before plants evolved, there was almost no oxygen in the atmosphere because it is a highly reactive chemical that quickly rusts minerals on the earth’s surface. Indeed, that is the very reason cosmologists searching for life on other planets look for an atmospheric oxygen signature.
Plants evolved at a time when the CO2 level was up to 20 times higher than today. The need for photorespiration was therefore negligible, and the earth was incredibly rich in greens. In fact, that early golden age, the Carboniferous Period 299 million to 359 million years ago, is the source of nearly all coal deposits on earth.
But as organic material was fossilized, it sucked almost all the CO2 out of the atmosphere, dramatically reducing plant productivity. During the ice ages, the cold oceans absorb so much carbon dioxide that plants nearly suffocate. That’s why, at the depth of the last ice age some 20,000 years ago, the earth became mostly desert and steppes.
It was only when carbon dioxide levels rose sharply about 10,000 years ago that plants started growing well enough to make agriculture possible.
Bringing Back Life
Now, through our economic activity, humans are bringing back into the atmosphere some of that fossilized carbon, and plants are growing better than ever. It has the same effect on productivity as the photorespiratory shortcut that the Illinois scientists have engineered.
Consequently, the bio-engineered plants can be utilized to more efficiently reduce CO2 levels in the atmosphere through re-greening of the earth. Despite the narrative of the United Nations, our carbon emissions might not have such dramatic effects on the climate.
Nevertheless, should carbon emissions ever turn out to be a real problem, the solution may be to sequester them in genetically enhanced plants, all while making food cheaper and reducing the amount of area needed for agricultural land. It demonstrates the power of human ingenuity.