Keeping Food on Your Plate

I’ve been a lighweight environmentalist for a long, long time.  My attempts to go “green” extended to participating in recycling programs, using CFL lights, using “green” cleaning products, and turning the lights off when I left a room.  I’d read about climate change way back in college and it sounded concerning but it also sounded far off and iffy.  In the past three years, though, I’ve been reading more and more scientific papers that have got me very worried about the not so distant future.  I’ve become galvanized—passionate about trying to get the word out and wake people up to what I perceive to be a potentially devastating crisis coming down the pipeline.  As I see it, climate change stands to significantly disrupt human life much sooner than I think most people (even climate scientists) realize.  If we, and by we I mean the developed/developing, industrialized countries of our planet, don’t get carbon emissions slashed and soon, things will not be good.  The specific nature of my concern is that—rather suddenly—food production in America may essentially collapse.  You might not agree that my concern is valid, but to understand the origins of it requires an understanding of some important aspects of plant biology and photosynthesis.    

All plants on Earth engage in photosynthesis to grow and build their tissues.  In a nutshell, they pull in carbon dioxide from the atmosphere through microscopic holes in their leaves along with water molecules from the soil and—in a rather complex process powered by energy from light—use them to build organic molecules like sugar.  A waste product of photosynthesis is oxygen gas, which the plants get rid of through the same tiny holes in their leaves that let in the carbon dioxide.

Bear with me on this next bit.  There is a problem with using those tiny little holes in the leaves for gas exchange.  Plants lose water via evaporation from them (like sweating for a plant.)  It’s not a major issue normally, but on a very hot and dry day plants can risk a fatal case of dehydration.  Thankfully, they are able to close the holes in their leaves when they start losing too much water.  Less thankfully, when those holes are closed plants can’t access carbon dioxide and they can’t photosynthesize well.  That means that on very hot, dry days most plants lose 50% or more of their carbon fixing (and growing) abilities.  Some types of plants, those that are commonly found in deserts and grasslands where conditions are both dry and hot, have developed tricks to get around this problem.  Most plants on Earth, however, have not. 

Of the plants that haven’t figured out how to keep growing well in hot, dry conditions are nearly all major agricultural plant species.  Corn, soy, and wheat are all highly susceptible to reduced crop yields when temperatures get above 90 degrees Fahrenheit.  When climate scientists use “low emissions” data in their simulations their computer models generate scenarios in which the mid-west U.S. experiences approximately thirty days each year with temperatures above 90 degrees and seven to ten days each year with temperatures above 100 degrees.  Under those conditions, American farmers would see drastic drops in crop yield regardless of how much they irrigated or fertilized.  Corn, soy, and wheat plants simply don’t grow well when it gets that hot.  When climate scientists plug “high emissions” data into their simulations, the computer models push the number of days above 90 degrees to between fifty and sixty each year—that’s basically the entire growing season!  The number of days above 100 degrees jumps to about thirty.  Some folks argue that those computer simulations are total garbage and the resulting predictions are absolutely meaningless but the men and women who developed those simulations aren’t total morons.  Far from it, and while I’m willing to bet they aren’t completely accurate I’m also willing to bet that in fifty years the American corn belt is going to be a LOT hotter than it is today.

That is the foundation of my concern regarding climate change, but there is more to the story of food production in America that has me worried.  It’s bad enough to imagine a summer heat wave that cuts production of the three main food crops that feed our country in half.  Two or even three years in a row of such an event (which the scientific community predicts will become the new normal) could cause an economic crisis in our country as food prices of everything on the supermarket shelves that contain corn or wheat (which is almost everything) sky-rocket.

There is a compounding problem with corn, the number one agricultural crop in our country.  It stems from a basic biological fact that any corn farmer will confirm for you.  Corn doesn’t pollinate when temperatures are above 95 degrees Fahrenheit.  There is a one to two week window in which corn crops drop their pollen onto the waiting tassels below, and if things go well the tassels turn brown and dry up and a big, fat ear of corn develops (two per plant).  But if during that week or two long window there are a few days of temps above 95 degrees then the ears develop with only some actual corn kernels.  Corn farmers know this and time the planting of their corn crops so that the pollination period falls either a bit before or a bit after the hottest time of the year. 

If climate scientists are even close to being correct in the predictions I shared above, then successfully timing pollination to happen when temperatures are low enough will become truly dicey under the low emissions scenarios and flat out impossible under the high emissions scenarios.  Can you imagine a situation in which farmers in the Midwest can no longer grow the number one crop in America, the crop that feeds most of us either directly or indirectly (most of the meat that you buy in the stores was produced from animals that are fed a corn diet)?  A single year in which farmers lost their corn crops could cripple our country.  Two years in a row?  The new normal?  Forget it.

Was it Napoleon who famously said that an army marches on its stomach?  Well, so do countries.  So do civilized societies.  Climate scientists might be wrong, but I for one am not willing to make that gamble.  The biology is what it is and should climate scientists be even close to correct the impacts on industrial agriculture will be swift (a single growing season or two) and unavoidable.  The reason I promote large-scale carbon reduction projects as well as individual and cultural changes is because I want to make sure that we and our children can keep food on our plates.