Warming of the planet from carbon dioxide (CO2) and other so-called greenhouse gases is a problem in contrast to what some still believe, and a problem that will not go away. Much like alcoholism it persists despite denials of its existence. The problem arises from our burning of fossil fuels, such as coal, oil, and gas. Generally speaking, there are three ways of dealing with the problem: First, prepare as best we can for a globally warmed world, second, switch to greener sources of energy, and third, sequester carbon from the atmosphere. In, At The Tipping Point: How to Save Us From Self-Destruction, I cover each of these options in detail. Even ten years ago few spoke openly about relying on the first option, but more and more I hear politicians stating this very option. However, it is very sad when it comes down to just allowing a fully globally warmed world to occur with all the associated costs. Given our technical capabilities, which largely created this problem in the first place, we should be able to solve the problem. Of course, part of the solution involves checking our endless growth economic model with the associated hyper-consumerism, something few seem open to. The second option, switching to greener sources of energy frequently falter because they often run counter to the endless growth economic model. In addition, our energy needs are so great that it will be very difficult, if not impossible, to supply all that we need from green energy.
The best option we have is to sequester carbon from the atmosphere, with one possibility consisting of machines that can do this. Unfortunately, when the carbon costs of producing all the associated piping to transfer the carbon underground are considered, this option loses its lustre. However, there is a way that actually has numerous spin-off benefits and will help return the planet to a more natural state: Converting our major annual seed crops to perennials. Annual plants only last a year with their roots dying off, whereas perennials last more than a year, the roots remaining alive. Annual seed crops include wheat, corn, rice, soybean, sunflower, oat, barley, chickpea, common bean, peanut, pearl millet, rape, and sorghum. Perennial fruits include apple, apricot, avocado, banana, blackcurrant, grape, kiwi, pear, pineapple, plum, strawberry, and raspberries. Perennial vegetables include eggplant, broccoli, asparagus, leek, potato, rhubarb, spinach, taro, sweet potato, and watercress. Perennial herbs consist of alfalfa, basil, dill, garlic, ginger, horseradish, lavender, mint, onions, oregano, sage, and thyme. We are then very familiar with perennial crops, and of course there are trees that are perennial.
When it comes to annual plants there are several problems. First, because the plant dies off each year they are net releasers of carbon to the atmosphere. Second, given their limited root structure they are very poor at retaining water, and with dwindling fresh water supplies this is a major issue. Third, due to how weak they are we have to add nutrients such as nitrogen that commonly run off with fresh water polluting waterways. Global data for corn, rice, and wheat annual crops indicate that only 18-49% of nitrogen applied as fertilizer is taken up by crops while the rest is lost. Herbicides and pesticides also have to be liberally applied with health costs.
Perennials, on the other hand, with their extensive root system are great absorbers of carbon from the atmosphere. The soil carbon sink is the fastest carbon sink, and the only one that can really help get global warming under control quickly. The oceans absorb a great deal of carbon but it is a slow process that is currently destroying coral reefs due to acidification. Rocks can absorb a massive amount of carbon but this process occurs over thousands of years. In addition to the carbon sequestration value of perennials there is water retention: The roots of perennials hold water and release it when needed, thereby minimizing irrigation needs. In addition, perennials retain nutrients eliminating or greatly reducing fertilizer use. Via artificial selection, hybridization, and utilization of genome knowledge, all of our major annual crops can be converted to perennials. Ten of our thirteen most common annual seed crops, such as wheat and rice, have natural perennial relatives, an occurrence that will greatly assist in the conversion. The United Kingdom’s Biotechnology and Biological Services Council has calculated that if we replaced only 2% of annual crops with perennials, we could remove enough carbon from the atmosphere to halt the increase in atmospheric CO2! If we were to replace all farmland with perennials we would sequester about 118 parts per million of CO2, enough to return the world to preindustrial levels! Another option is to replace our agricultural lands and cities with trees, but I doubt that this option will be accepted.
So why is replacing our major annual seed crops with perennials, an incredible option, rarely discussed, and why is funding so limited for it? Very good questions. Part of the answer might have to do with the annual seed agriculture industry. Annual seeds have to be planted each year, then there is all that fertilizer, herbicides, pesticides, not to mention expensive irrigation equipment. Perennial agriculture might well seem like a threat to profits, and in our endless economic growth system it’s mostly about products and profits. Instead of making the conversion, which scientists estimate could occur in even twenty years, let’s just prepare as best we can. Really?
For more information about converting our major annual seed crops to perennials read the free pdf of the Too Hot to Handle: Global Warming chapter, from my book, At The Tipping Point: How To Save Us From Self-Destruction, available on this blog site.