You would think, I think intuitively that energy would be the dominant way that humanity is impacting the planet. We’ve just seen how massive energy use translates into rising carbon dioxide and climate change. And energy, of course, is everywhere in our transport systems, our power supplies, our industrial processes, our home use. But it’s quite arguable I would say it is right to say, that the agriculture sector has an even larger impact on the physical planet and the various earth systems than energy. Energy is causing climate change. Agricultural use and agricultural patterns not only have a huge impact on climate but have a huge impact on every aspect of the Earth’s systems and the planetary boundaries.
We’ll see soon that the food production contributes massively to greenhouse gas emissions, therefore to climate change. But we’ll see also that the energy system as we go around the the circle is in a way dwarfed by the food production system in its impacts on each of the other areas of the, the planetary boundaries. The nitrogen and phosphorous cycles, where we get the pollution from the runoff of nitrogen and phosphorus-based fertilizers. The fresh water use, which is about 70% used in the agricultural sector. The change of land use overwhelmingly a reflection of agriculture. The loss of biodiversity coming from the way that farmlands and pasture lands and and tree crop plantations absolutely threaten habitats of other species unless uh,agriculture is done in an agro-ecologically friendly manner. Chemical pollution with the heavy application of chemicals such as herbicides and pesticides used in agriculture. There’s a tremendous amount of chemical impact from the farm system. So it is quite arguable that farming dominates the all of the human activities in terms of the anthropogenic effects. Anthropo, human. Genic, caused by. That is the various human-caused impacts on the planet.
Now this is in a way ironic because it takes us right back to the beginning of the modern economic era and to the very beginning of economic studies just like Adam Smith does and just like Adam Smith’s wisdom is still useful today, so too is that of another great thinker Thomas Robert Malthus who wrote famous text in 1798 called Principles of Population. Malthus was afraid. He was also afraid of planetary boundaries, but for a slightly different reason. Malthus said that the human population has a tendency to rise at a geometric rate. And so if left on its own with the basic needs met the human population would continue to expand rapidly. He was right in that when he wrote the Principles of Population in 1798. The total population may have been 800 million, maybe 900 million. Roughly one tenth of the level that it is today. So Malthus was right that human population tends to increase markedly, at a geometric rate he said. Now, he feared that the ability to grow food would only increase at an arithmetic rate. That is adding a certain number of tons of feed grain or food grain per year to the world’s capacity to grow food. And Malthus said, look, any geometric growth will always overtake any arithmetic growth. So the growth of the human population is always going to overtake the ability to grow food, he said. And at some point there will be so many people that hunger will ensue. And when hunger ensues there will be various kinds of devastating feedbacks whether it’s war, whether it’s famine, whether it’s disease or other scourges that will push population back down. But will mean that humanity won’t break free of the physical constraint on the ability to grow food.
Now Malthus did not anticipate the scientific advances of the Green Revolution, for example. He didn’t anticipate modern seed breeding of course even Mendel who invented the modern science of genetics would come basically about three quarters of a century after Malthus. Malthus also didn’t anticipate the breakthroughs in the science of soil nutrients and the use of chemical fertilizers to replenish soil nutrients and to boost food yields. Nor did he anticipate at least the potential for the human potential to stabilize by means of modern contraception, family planning, and choices that households make. So Malthus, couldn’t see the full dynamic ahead, but he worried that the human population would outstrip the carrying capacity of the planet itself. For a long time, economists and others laughed at Malthus. They said, you’ve got it all wrong. You see modern science allows us to grow enough food for a geometric rise of the population. We know how to add fertilizer, we know how to have high yield seed varieties. But, you know, Malthus’ a pretty clever guy and he had a real insight and we’re not done with his story yet because his warning rings true today.While it is the case that increases of food production technology in agronomy and food processing, storage, transport and the ike has made it possible to feed 7.2 billion people though not all of them by any means fed well or nutritiously. It is also the case that the food production system is so destructive of the environment that Malthus is still there, waving his finger saying not so fast. You haven’t proven that you can grow this amount of food sustainably.
What’s going to happen when the water runs out? What’s going to happen when the nitrogen and phosphorus loadings become so large and so forth. So I would say we’re not at the end of the Malthusian story yet. Sustainable development calls for a renovation, a reform, an upgrading of the technological systems to grow food. It calls for us to eat more wisely as well. Eating the kinds of food products that don’t threaten the natural environment. For example, not eating endangered fish species or endangered species of land mammals. Unfortunately some of which are in huge supply as delicacies, even to the point of illegal hunting and poaching and threatening the very survival of these species. So, changing farm systems and changing human behavior, in terms of our diet and use of agricultural products, is possible. But in order to meet Malthus’s challenge, we still have to prove that it’s possible to grow food in a sustainable manner
For all of the people properly nourished on the planet, and with the food system recognizing and respecting the planetary boundaries. Boy, are we far from this today. Let’s think about some of the ways that the food system is impinging on the planetary boundaries.
First, the food system is an enormous source of greenhouse gases. Of course agriculture uses a lot of energy. For planting, for harvesting, for storing, transforming and transporting food and other agricultural commodities. There’s a lot of energy stored in chemical fertilizers, because to make urea, or other nitrogen based fertilizers, one requires a lot of energy to create the chemical compounds in those fertilizers. But what’s interesting and important for us to note, is that agriculture emits greenhouse gases in other ways as well. Remember, the two other major greenhouse gases, anthropogenically caused, that is, caused by human beings in addition to CO2 are methane and nitrous oxide. Now methane or CH4 is emitted in a variety of ways. It’s emitted by anaerobic processes in flooded or paddy field rice for example. Where the metabolic processes of the bacteria release methane into the atmosphere. It’s also released from the gut of ruminant livestock. When cows chew their cud, and digest their food they are also emitters of methane on, on a large scale. Nitrous oxide is emitted partly through industrial processes and electricity production at coal fired power plants. But it’s also emitted by the chemical decomposition of nitrogen based fertilizers. So fertilizers are a source of nitrous oxide in the air.
But they’re also a source of water pollution in the sea. In both cases, the nitrogen is supplied on the farms, but it’s not taken up by the plants themselves. It either volatilizes into the atmosphere or it runs off into the water and then, on the way through the rivers and ground water to the ocean. So greenhouse gases is one major way that that the agriculture system impinges causing climate change. Land use change and habitat loss is another obvious way. Humans use land primarily, not for our cities, not for our highways, but for our farms and our pasture land and our timber land. And we have already taken hold of so much land, so much photosynthetic potential, to feed us, that we’re depriving other species, not only of their natural habitats, but of the food that they need to stay alive. And that’s why we’re driving numbers of other species down sharply. Agriculture, as I mentioned earlier, is a major source of chemical pollutants often very long lasting and very toxic chemicals that are used as pesticides and as herbicides and as other parts of the food production chain.
Agriculture has another perverse threat which is called invasive species. Invasive species means that humanity advertently, or inadvertently, but generally unwisely takes a species from one part of the world, puts it into another environment, perhaps where there’s no competition with that species. If it’s an animal, it can run wild. If it’s a plant or a weed, it can take over a a land area, or a lake for example, dominating the local biodiversity. Invasive species means that we are rearranging the biogeography. The places on the planet where various species exist. And we’re putting lots of species at risk by invading ecosystems where they don’t belong, where they are not native. Perhaps where they have no predators, or where they can invade and take over a lot of the resources of that ecosystem.
Nitrogen and phosphorus runoff, I’ve already mentioned. And look at this picture. The shocking picture off the coast of China there is so much fertilizer being used by Chinese farmers because it’s heavily subsidized, and because of bad farm practices that that fertilizer runs off the farms into the rivers and ground water. It accumulates in the estuaries and off the coast, and it creates this kind of algal bloom. And algal bloom means that there’s such a sudden massive loading of nutrients, nitrogen and phosphorus in particular that the algae which either naturally grows in a particular place or has been introduced say by fisheries practices, suddenly has this massive feast of nitrogen and phosphorous. And there’s an explosion of the amount of algae. This algae will die. Then it will be decomposed by bacteria. As those bacteria feast on the algae, the dead algae, they will be respirating, and they’ll be using a lot of the oxygen in the water. They will deplete the oxygen as part of the respiration process and by depleting the oxygen they will create an oxygen depleted zone of coastal waters. That’s called a hypoxic zone, low oxygen hypo oxia. And low oxygen kills the fish, kills the other species. Suddenly you have what ecologists and marine biologists call a dead zone. There are dead zones all over the coastal world now, especially in the estuaries.
Estuaries where the freshwater of rivers meets the saltwater of the oceans are wondrous ecosystems. Our shellfish and many other species are often indigenous to those locations, and they’re being threatened by this nutrient loading. By the utrification and then by the hypoxia that results. Creating dead zones and hypoxic regions in more than 130 estuaries around the world. The food system also gives rise to new pathogens. When we have the industrial breeding of poultry, for example, all crowded together, we have learned that there is recombination of genes of bacteria and viruses. When livestock and poultry out in the open mixed with the wild with the wild species of geese and other species, you get further recombinations. And this has given rise to many emerging infectious diseases, some of which are very, very frightening, like SARS. Was and remains very, very frightening. And so we have new and emerging diseases coming from industrial agricultural practices. Of course we have massive overharvesting, overhunting, overgrazing,over abstraction and cutting down logging of trees and forests. Most of the world’s major fisheries have been massively over fished.
In the Northeast of the United States where I live there was a collapse of the cod fisheries because of the massive amount of fish that was being hauled up using modern technologies trawlers and other high tech ways to fish a massive amounts of fish under the ocean.
And of course with all this food production we are using up water supplies through ground water depletion, through the diversion of rivers which no longer make it all the way to the sea. And the growing water crisis is extraordinarily frightening.
We see water scarcity as a major threat to well being, to human health, to economic development in many, many parts of the world adding climate change on one side, overuse of water coming from agriculture it’s quite a dangerous brew. So just as we are going to need to find a new pathway for energy basedon energy efficiency and low carbon energy supplies. We are going to need to find a new farm system, or I should say farm systems. Because there are farm systems distinctive all over the world depending on the local climates, local cultures, local soils, local ecological conditions. But what is nearly common to all of the major regions is that our farm systems are not yet sustainable.
We still have to prove Malthus wrong, we still have to take a tip from Malthus that the challenges of food supply are a major and continuing challenge facing humanity, and a core part of any agenda of achieving sustainable development.