Arquivo de etiquetas: Segurança Alimentar

Lectures / Readings

Sustainable Food Supply and the End of Hunger V

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Towards a Sustainable Global Food Supply

Creating a sustainable farm system around the world is absolutely vital to feed a growing world population. And to reduce the tremendous pressures that our current farm system, or systems around the world, are already placing on the Earth and many of the key ecosystems on the planet. We can think about what will happen if we continue with business as usual. And contrast that with what we really need to do, which is to reshape our own behavior with regard to food and to reshape the farm systems that produce food to create an alternative of trajectory, a trajectory of sustainable development. What are the threats of the business as usual path? The chart before you attempts to summarize those risks and to give an expert assessment of how serious the particular risks are in particular regions of the world.

1051The boxes that are shaded red are major alerts that these are places in the world and kinds of challenges that are of the first order of significance. The boxes that are yellow are like yellow warning signs, things could get bad in these areas with regard to these particular threats. Business as usual, for example, will mean increasing food insecurity in some parts of the world. The places at greatest threat are Sub-Saharan Africa and South Asia, the two epicenters of under-nutrition. But also one would add North Africa and the Middle East. Why? Because this is a place where all of the climate evidence suggests there will be significant drying in the future, and therefore, crop production will be under even greater threat than it is today. Certainly the business as usual course will put dangers in East Asia and Southeast Asia as well because there will be places of tremendous water stress. There will be places where higher temperatures play havoc with the food supply. Malnutrition in the sense of deep undernourishment, of course, will continue to have it’s intense epicenter in Sub-Saharan Africa and in South Asia. But the other kind of malnutrition, obesity. On a business as usual path is likely to worsen significantly in North America, in many parts of Latin America, it’s already epidemic proportions in Mexico for example, in Europe, and with serious risks in Southeast Asia, in in East Asia. And in India and in other parts of South Asia as well. Land use change we know will have huge costs especially in the rain forest regions. That means in Latin America, in Sub-Saharan Africa. And in parts of Southeast Asia. Soil degradation is already a major crisis in, in parts of Sub-Saharan Africa. In many place in south and in east Asia, where the land has already eroded the soils often have been swept away because of trying to grow crops on steep slopes for example. Or in places where the winds blow the topsoil away, as is occurring in many parts of China. We know that biodiversity loss is threatened pervasively. One could say that the threats are moderately or acutely high in every region of the world. One can think about losses in the rain forest regions, one can think about losses in the places likely to experience serious drying such as the Mediterranean basin. One can think about losses of biodiversity in places where population growth is so rapid that encroachments on land that are bound to threaten and profoundly imperil biodiversity as is occurring in Sub-Saharan Africa. The chart in other words by region, by risk. Is filled and while there are a few regions that escape some of the risks, there are no regions that escape all of the risks. And today’s poor regions are of course as is usual with poverty, at extreme peril because they’re already living on the edge. They’re already people living in fragile environments, for example in tropical ecosystems in dryland ecosystems, part of the their poverty has come from the fact that the, natural environment is already fairly inhospitable. But with environmental change, what is now a difficult environment, can be a, an impossible environment to support human life. When that happens, not only will people suffer, will people die, will there be conflict, there will be migration. And there will be environmental refugees created by the millions, the tens of millions, even the hundreds of millions. And we know, sad to say in a world which does not do well with migration. Where newcomers, especially poor newcomers that are forced to move ,uh, can face a very, very hostile environment to when they arrive and so we’re in for a lot of trouble if we maintain this business as usual trajectory. What to do? How to move to a sustainable development trajectory? Again, because of the complexity of the food system, the fact that we’re talking about land use, the fact that we’re concerned about nitrogen use, the fact that we’re concerned about chemical pollutants, the fact that we’re concerned about the vulnerability of crops to higher temperatures or more water stress. Means that the kinds of responses that are needed, also are going to have be varied, holistic in nature, and carefully tailored to local contexts. Boy, that makes this among the toughest challenges that we face because the world is in crisis. The problems will get worse. It’s not easy to say that one region will bail out the others because all regions will have stresses. And also there will be no magic key that suddenly will sweep the world, and make it possible to solve this problem. Each region is going to have to identify its own pathways to sustainable agriculture. What are some of the things that can be done? The first is to improve our ability to grow food. And to be more productive in terms of higher yields, and more resilient in terms of the ability of food crops to withstand the shocks that we know are already coming. Just as Norman Borlaug and his colleagues Emma Swaminathan and Minister Supranamian. That triumvirate made possible the Indian Green Revolution and comparable events in other parts of the world where higher yields came because of the advent of high yield varieties combined with fertilizer inputs and often with irrigation. We’re going to need another Green Revolution of new crop varieties that are going to be especially propitious for the challenges that we face. For some regions this will mean a special importance of drought resistant varieties. Because the frequency of serious droughts is likely to become much higher. We know that certain plants in nature have a high level of drought tolerance. The plant scientists now are attempting to identify those genes and through various means, conventional plant breeding or the use of genetic modification as it’s called, create new crop varieties that also share, the drought resistance. Partly the natural breeding has helped to develop new seed varieties that are better able to withstand bouts of of low rainfall, in other words dry spells during the growing season. GMOs, the genetically modified organisms, or GMO crops have taken the experimental pathway of identifying the gene complexes in naturally occurring, drought tolerant plants. And transplanting those gene complexes into crops that for the food supply. Now many, many people find this idea of genetic modification to be very threatening, very dangerous, and it poses risks to the environment and potentially to human health. So, whatever is done in this research domain of using cutting edge genomics, both to identify potential genes that can add to crop traits that are desirable, and then to transplant them into food varieties to raise the resilience of those crops. Needs to be tightly monitored and tightly regulated. But I would argue, despite some critics of this technology, that we should certainly test these technologies to see what they have to offer. They seem very promising. That by identifying genes for drought resistance or by identifying genes for saline tolerance, for saline soils, or for identifying genes as shown in this picture for the ability of rice to resist submergence. We can get major advances. What you’re looking at in this picture is a transplanted gene from a species of rice that is able to tolerate being underwater for several days and still survive. To the kinds of rice that are normally grown in Bangladesh, in India, in Pakistan or other parts of Asia, that don’t have that submergence trait. Turns out, wonderfully, taking that gene for submergence and putting it into popular, high yield traits for rice, has led to high yield, submergence-tolerant rice a wonderful breakthrough for farmers in Bangladesh that suffer repeated episodes of submergence of their rice. Those who say don’t even go that way with technology aren’t thinking, in my opinion, clearly enough about the needs of that farm family in Bangladesh to have this kind of variety. We shouldn’t dismiss a whole class of technology, because while it may pose risks those risks are controllable, monitorable and the technology itself can offer important breakthroughs. Now, relatedly is a second step of what can be done. And this is to make crop varieties more nutritious. Not only to grow better in harsh conditions, but to express more nutrients and this is the idea that you’re looking at, in this picture of so-called Golden Rice. This is a, a crop that has been developed by the International Rice Research, Rice Research Institute, in Los Banos, Philippines the Rice Research Institute that helped bring the Green Revolution in rice. Now what scientists at IRRI, I-R-R-I, are doing is to put in genes that express beta carotene, a precursor for vitamin A. So the children who eat this rice, and you see how it’s golden or looks more red, a little bit more like a carrot carrot color then have the vitamin A that they need for health. And we’ve already identified that vitamin A deficiency is one of the key kinds of hidden hunger. How wonderful it will be if a nutritious rice that provides a basis for vitamin A can successfully be diffused and taken up by populations of rice eaters around the world. A third direction for us, absolutely essential is known as precision farming or information rich farming. This is already being used in high income countries by relatively wealthy farmers who can afford high tech approaches. But in coming years, because of the declining costs of information technology, it will increasingly be used by by poor farmers as well. What precision farming means is having a much more precise application of fertilizer, for example. Just in the places where the soils require it. Not in the places where it’s not used and just in the amounts that can be taken up by the plants without experiencing the harmful side effects of the massive run off or loss of that fertilizer, both into the waterways and into the atmosphere. Precision agriculture depends on information technologies, on detailed mapping of soil types, often on on global positioning systems that can tell a farmer exactly where that farmer is in the field, and what’s happening in the soil in that part of the farm. That relates more to, to a more general category of, better nutrient management through better soil testing, soil mapping using a, a local chemistry. Even reading the qualities of the soil on handheld devices. Or from satellite, it will be possible to get a much more detailed resolution of soil needs. What needs to be added here, what needs to be added there, where’s fertilizer not needed or needed only in very small amounts? And that sort of nutrient management of the soils offers places with soil nutrient depletion a massive potential boost in yields, Africa  being number one in the line for that. It also offers the chances for places that use far too much fertilizer, like China, to cut down very, very sharply on the fertilizer use. Another breakthrough is water management. Of course, we need to apply less water to get more crop per drop, because we’re depleting the scarce water we have, and the conditions will get tougher in the future. Not only because of the depletion, but because of the climate change. Another major breakthrough that offers us a real boost will be better harvesting, storage, and transport of crops. To avoid the very large losses, sometimes estimated as, as much as a third, or even 40% of the crops to post-harvest loss, to pests, to rotting to rodents, to physical loss of the crops left to exposure to rains and so forth. Simple means of more effective storage systems at very,very low cost and better incentive systems and empowerment of local farmer cooperatives to invest in community-based storage facilities offer a tremendous hope for reducing losses in the value chain of agriculture. With big gains not only for farm incomes, but also big gains in effective productivity of the farm systems, and our ability to ease up on the big human pressures, on the farm systems. Next I would argue that better business models  for poor smallholders is vital not only for ending extreme poverty but also for making all of these investments in more efficient crop varieties, more efficient irrigation more efficient water management, more efficient storage. There is productivity through aggregation into farmer cooperatives. Farmer based organizations, new kinds of models, new connections to local, regional, and global value chains that are already proving their worth. And finally, we have to take responsibility ourselves for our health. And for the way we approach the issues of food. When we have massive epidemics of obesity. We know that something is seriously wrong. A lot of it comes from the fact that we have heavily subsidized the wrong kinds of foods. We’ve heavily subsidized carbohydrates or trans fats, or other kinds of, of foods stuff that are absolutely unhealthy in the ways that they’re being consumed right now. And, our economic incentives have often played against the very kinds of foods that are better for our diets, for our health. We have subsidized in effect the feed grains that have led to massive and the evidence shows from a health point of view, an environmental point of view, overconsumption of beef in the United States and Europe. To the point where so much meat is eaten that it’s bad for human health, contributing to cardiovascular and other diseases, and it’s exceedingly bad for the environment when we are deploying ten or fifteen kilograms of feed grain for every kilogram of beef that is consumed. Tremendously multiplying the burdens on the land, on fertilizer use, on water supplies, aggravating all of the natural problems. We’re also aggravating these problems by diverting food production, or what should be food production, into the gas tank. In the United States through absurd subsidies driven more by politics than by any common sense or ecology, we’ve turned a significant part of our annual food and feed grain production, especially of maize into ethanol for automobiles. It’s a miserable deal because so much resources used to produce that ethanol. It’s creating no savings for the natural environment but what it is doing is diverting a tremendous amount of food and feed grain away from the the food systems. It’s pushing up food prices. It’s putting extra pressures on the natural environment. It is being done at the behest of a few powerful companies with powerful lobbies in Washington. And Europe isn’t off the hook because it has a similar problem of biofuels diverting valuable farmland in Europe. The pathway to sustainable development involves behavioral change, public awareness, taking responsibility, and the mobilization of new systems and new technologies that can dramatically reduce the pressures on the natural environment. And help to make our economy and our way of life more resilient to the environmental changes that are already underway. It’s a huge problem and a huge challenge. It’s an unsolved one. It’s one of the areas that will require the most intensive kinds of problem solving, at local levels all around the world, during the period of the sustainable development goals from 2015 to 2030, the years that lie ahead.

Lectures / Readings

Sustainable Food Supply and the End of Hunger IV

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How the Food System Threatens the Environment

So we have a big problem. The problem is how to grow enough food and the right kind of food for a healthy and growing population. And we’ve seen that the problem’s going to get tougher as the population grows. And as the environmental threats multiply in the coming years. But the problem’s even more complicated. And that is that agriculture itself is one of the major causes of environmental threat.

The agricultural sector is the single most important sector from the point of view of human-induced climate change, and other environmental damages to the planet. I always find this a little bit counterintuitive. I think the automobile age, that must be the big, damage to the environment the energy system and fossil fuels. Of course those are huge factors in climate change and in environmental costs. But if we look at a particular sector of the economy we come back to the original one, to food production itself. And to agriculture more generally as the key human activity that puts the most pressures on the planet. What kinds of pressures? I think it’s worth mentioning quickly, before delving more deeply into three of them, the range of pressures that the agricultural system and farm practices put on the planet. First is greenhouse gasses.

1041We’ll turn to this in some detail, but the farm sector is a major emitter of the three main greenhouse gasses; carbon dioxide, methane, and nitrous oxide. And this by itself means that farm practices need to be rethought as we desperately need to move to a low carbon and a low greenhouse gas emission world.

The second major impact Is through something very rarely discussed in in in the, the public but of increasing concern among specialists and that is on the nitrogen cycle. There’s a natural nitrogen cycle our atmosphere is 79% nitrogen in the form of N2. That kind of nitrogen is inert odorless without taste and not very useful, actually, for us. But nitrogen in it’s reactive forms of nitrates and nitrites and ammonia and ammonium, ion, and, its other reactive forms is absolutely vital for us and for all the rest of, living, species. Because nitrogen’s the backbone of amino acids and of proteins, it’s absolutely core to our metabolism, and to every aspect of our lives, including the ability to grow food. It’s for that reason we put a lot of nitrogen on the soil in the form of nitrogen-based fertilizers, to help feed the nutrients to our crops so that our crops feed us. But the damage of that human intervention into a natural nitrogen cycle is enormous. We’ll look at that in just a moment.

A third major way that the farm system impacts on the planet is the destruction of habitat for other species. Not entirely surprising when we consider that 40% of the total land area of the planet is agricultural land whether the arable land or the meadows and pasturelands. Humanity’s already grabbed so much of the land area for us, but it’s grabbing more, especially in the form of deforestation, and the rain forests that are at risk right now are places of incredible and irreplaceable biodiversity. And so one of the major ways that the earth is vulnerable to the sixth rate extinction wave that we have already discussed is through the tropical rain forest deforestation, which is part of the ongoing process of clearing lands for arable and for pasture land.

There are many other ways, which I’ve mentioned, where the environment is at threat from farming activity. The pesticides, the herbicides, the other chemicals that are used in farm production are a major threat to biodiversity. And especially the massive amounts of water that are used, around 70% of the total human use of fresh water goes through agriculture with only 10% going through household use and the remaining 20% or so for industrial processes. Agriculture is a voracious user of water and that water, itself, is under threat. So, for all of these reasons, the agriculture sector Is a key driver of anthropogenic environmental loss, and we’re going to need to change technologies and processes and patterns of land use to make the food system compatible with a sustainable planet. Let’s have a look at the first of those three drivers that I discussed. Climate change, nitrogen cycle, and land use where I want to look more deeply at the role of agriculture.

This pie chart shows us the estimated total amount of greenhouse gases that are emitted, allocated across the various sectors of the economy. The power sector for example, through the burning of coal, oil and gas, is responsible for a massive amount of CO2 emissions, and for an estimated 24%, roughly a quarter of the total greenhouse gas emissions.

The transport sector, the internal combustion engine in the cars and in the trucks, is responsible for an estimated 14% of total emissions. Industrial processes, for example, steel production or petrochemical production, another one-seventh or 14% of total greenhouse gas emissions. The non-energy sphere is responsible for around one-third of the total greenhouse gas emissions. 1042That is CO2 emissions, methane, nitrous oxide, and chemical pollutants from specific chemicals like hydrofluorocarbons that are not the emissions from the combustion of fossil fuels. Within that category, agriculture plays a huge role. Of course, agriculture emits greenhouse gases in the transport sector in tractors and in transport of food. It emits greenhouse gases in the industrial sector for the production of chemical fertilizers. But there’s a massive amount of greenhouse gas emissions that is not directly from fossil fuels at all. This includes for example, the emissions that come from clearing forests. As the trees are chopped down, as they are burned, as they decay, CO2 that was sequestered in the forests are emitted into the atmosphere. And several billion tons every year of CO2 come from deforestation. Agriculture also is a major source, as I mentioned earlier, of the second and third ranking greenhouse gases. Methane, CH4, is emitted in certain crop productions such as paddy rice. And it’s also emitted through livestock, through the ruminants who through the natural processes of their digestion give rise to quite a lot of methane emissions, both from the front and the back of the animals, I should mention. And this also contributes to the increasing concentration of methane in the atmosphere, a very powerful greenhouse gas. Nitrous oxide, N2O, is also emitted from agriculture. It is one of the ways that nitrogen-based fertilizers degrade.

Instead of being taken up by the plants, they volatilize,  go into the atmosphere, they go into the the water supply. And one of these parts of the nitrogen cycle is from, the livestock and from the fertilizer use, into increased emissions of nitrous oxide. And this also adds to the total amount of greenhouse gases that agriculture contributes to the overall process. When you look at it, more than one third of total emissions are due to land use change such as deforestation, and the direct emissions of greenhouse gasses from agricultural production.

1043It’s astounding. Roughly one third of total greenhouse gases directly come from the agriculture sector, and there are bits and pieces more through the fertilizer manufacturing and through the direct expenditure of fossil fuel based energy as inputs to agriculture on top of that one third. So we see that indeed the agriculture sector is a major contributor to greenhouse gases, and to climate change. As well as the first sector to lose from this. This is a terrible two-way problem that needs to be addressed through improved agricultural processes, as I’ll be discussing shortly. Let me turn to the nitrogen cycle. The nitrogen cycle vital for life has been overtaken by humanity. Absolutely extraordinary. In nature the N2 molecules in the atmosphere are converted into reactive nitrogen through various biological processes of nitrogen-fixing bacteria, as well as through physical processes, of lightning, for example, that breaks the very strong triple bond of the N2 molecule and by disassociating the N2 molecule, leads to the formation of ammonia and other reactive nitrogen. In that normal process the cycle from N2, to reactive nitrogen compounds like nitrates, nitrites and ammonia, and then back through respiration uh,and through through biological processes to back to N2 is a natural nitrogen cycle. But humanity is now creating even more reactive nitrogen than nature itself. We’re doing it in our industrial plants at a mega scale, 100 million tons or more per year of nitrogen-based fertilizers. Back in the early years of the 20th century, two great chemical engineers, Haber and Bosch, developed a process that some consider to be the single most important innovation of the 20th century, one that almost none of us has heard of, in fact, but changed the world. The Haber-Bosch Process, so called, is a way, through application of high amounts of energy and the use of various identified catalysts, to break that N2 bond to create in a chemical process in, in a factory basis, ammonia. And that ammonia can then be used to provide the base stock for urea and other nitrogen-based fertilizers. Up until the Haber-Bosch Process, the nitrogen that was deposited on the soils either came from the manures of farm animals or it came from the mining of excrement off the coast of Peru and Chile of bats and birds, the so-called guano which was being mined as a nitrogen source for fertilizer for Europe. But it was being quickly depleted.

And there was a crisis at the end of the 19th century, what are we going to do with the encroaching nitrogen scarcity? Along came Haber and Bosch, the Haber-Bosch Process, nitrogen-based fertilizer. And what was then a world population of under two billion became during the twentieth century a population of more than three times that, and now reaching 7.2 billion people. And it was the advent of nitrogen-based fertilizer, among other things and including, of course, the high-yield seed varieties and other agronomic advances, that made it possible to produce enough food to support 7.2 billion people, even if, I must add, a large number of them, 3 billion, are not well-nourished on that food supply. But, with all that nitrogen now being converted from N2 into reactive nitrogen, we have a mega problem.

And the mega-problem is shown in this complicated flow chart of what happens to that nitrogen when it is used in the farms and then it runs off. In some ways, it enters the water supplies, nitrates, causing a danger to the water supply. Some of it runs into the rivers and the sea and we’ve already seen how that leads to algal blooms and nutrification.  some of it enters the atmosphere, no

t as N2O, but as NO2, which causes smog in our cities. And so from the fertilizer deposit come a host of problems. There’s addition to greenhouse gases. There is acidification of soils by the nitrogen that is put into the soils. There is the worsening water quality that comes from the nitrates and the nitrites running into the water supply. There is the damage to ecosystems of eutrophication of the estuaries. There’s the fall of air quality as the noxes, the NO2s, NO3s, and other, effects of the nitrogen enter the urban atmosphere to create smog, to create tropospheric ozone, and to create massive health hazards, in our cities. So here is a, a dilemma, that is a mega dilemma, and hardly discussed in our day to day life. We need the nitrogen for our food production, and yet the consequences of the nitrogen on the physical environment in multiple ways, from climate change to eutrophication to urban smog to poisoning of our water supplies, is growing. This map comes from a study showing estuaries around the world suffering from eutrophication, from nitrogen and phosphorous based fertilizers. A huge problem, these are the dead zones in our coastal areas, killing vital parts of the marine ecology. And the problem is growing and it is likely to get worse unless we address how to use nitrogen in a more responsible way.

1044Third area that I wanted to mention in-depth is the forests. And just to point out that the forest loss that is occurring in all of the great rain forest regions, in the Amazon and the Congo Basin and, and in the Indonesian Archipelago have multiple drivers that differ across regions. In the Amazon most of the loss of the rain forests has come through the clearing of the rain forest to make way for new pasture land and new farm land, or because of the building of infrastructure such as roads in the Amazon. In southeast Asia where there’s also a large loss, the drivers are somewhat different. The drivers there are logging for tropical hardwoods in huge demand for China’s booming economy, and also for clearing the rainforest to grow tree crop plantations, of which the fastest growing, taking over large areas in Indonesia and Malaysia, is palm oil. In Africa there is yet another driver and that is peasant small holder agriculture. Not clearing especially for tropical logging or for tree plantations or even for large pasture land, but just the spread of small holder farmers into the forest margin. And often a huge use of the forests, and an unsustainable use for fuel wood and for charcoal. In the wealthier regions of the Amazon in Brazil, and in in Southeast Asia, the fuel wood problem is not as severe because there are alternative energy sources. But in the Congo Basin for example, and in other forest areas of Africa where populations are very, very poor and where alternative fuel sources such as natural gas or or electricity are not available, charcoal is used in such large amounts that that is a key driver of the deforestation and a key driver of the loss of habitat. Clearly in each of these areas, in order to preserve habitat, protect biodiversity, reduce the greenhouse gas emission consequences of deforestation, actions are going to need to be introduced that are responsive to the particular challenges in those areas, and the particular needs of the local populations. This will play an enormously important roll in helping to reduce the rate of uh,climate change, but also will be absolutely vital if we are to succeed in heading off the massive loss of biodiversity

Bilhetes, Lectures / Readings

Sustainable Food Supply and the End of Hunger II

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Farm Systems, Ecology, and Food Security

One of the challenges of addressing the food security issue is how varied the farm systems are around the world. This isn’t surprising, the world itself is incredibly varied in what’s grown, where, how, climate, soils, topography biodiversity, all have an enormous effect in shaping farm systems. And because of that, there is certainly no single answer to how farms can become more productive for example. Or how local populations can become healthier in what they eat. Different places grow different foods. They eat different foods. They face different climatic and agronomic challenges. And, part of our proper, problem-solving our diagnostics and our solutions for the issues of a sustainable food supply, depend on us understanding, in detail, how these farm systems differ around the world. Well to do that, let’s take a look at the world in the big picture to get a very macro sense of how farm systems are shaped and how they differ in different places in the world. Consider the land area of Earth in its entirety.

1021There are about a 130 million square kilometers of land on Earth. And of that, a remarkably large proportion are already taken by humanity for human needs. Agriculture, meaning, both farmland, arable land, used to grow crops, and meadows and pasturelands, grasslands, used to feed animals, constitute together around 50 million square kilometers or roughly 40%, a little under 40% of the world’s total land area. This by itself is rather astounding. One species of the millions on the planet has requisitioned land for us to feed us. And when we discuss the declines of biodiversity, the first thing to keep in mind is how much of the output of food on the planet. How much of the photosynthesis on the planet is taken for human need, and how much that leaves the rest of the biosphere behind and threatened by this human grab for the planet’s primary production of, of food. So, 50 million square kilometers used for arable and pastureland, roughly of that, 14 million for arable, that’s for croplands. And roughly 34 million square kilometers for meadows and pasturelands. So, the farmland itself accounts for a little over 10% of the world’s land area. Pastures, much bigger around a quarter of the total land area on the planet in grassland regions used to graze animals. Another 39 million or so square kilometers is for forests. Many of those forests are managed forests, plantations for pulp and paper for example, for timber for logging. Some of those forests are not managed the boreal, vast boreal forests in the high latitudes as an example.

The forests in total account for another 30% or so of the Earth’s land area. The remainder is another roughly 30% it’s another 41 million square kilometers. A lot of that is desert. A lot of that is uninhabitable. A few percent of the world’s land area’s in our cities, where half the world’s population live, but we’re so densely settled in the cities, that the cities themselves, the urban extent only accounts for a few percent of the, 130 million square kilometers. Most remains either in the form of agricultural land, forest land or deserts and uninhabitable land areas. You’re looking at a map now, of where the agricultural land is. Both the crop land and the grazing land. And the colors here are showing you places where the cropland is very concentrated. Not every place where land is used to grow crops, but places where a very high proportion of the land in that area is actually arable or cropland, that’s the green shaded areas.

It’s the midwest of the United States, it’s parts of western central, and eastern Europe. It’s much of China and India. In Africa and in in South America you see land that is mixed in grazing land and in cropland. The drier areas tend to be places where food crops can’t be grown with high productivity.  If the rains fall below a certain amount during the rainy season, then crops can’t grow at all. And to the extent that people live in those environments, that they’re not desert, but rather are arid but not extreme hyper arid regions, they are places that are used for grazing animals. So livestock production tends to be in the drier areas. Nomadic populations, who are pastoralists full-time for their livelihoods, often with no crops at all, are living in places just on the margins of the desert. In Africa you see these grazing land areas just south of the Sahara Desert. In the top half of the African continent.

1022 And then around the Kalahari Desert in the southern part. The forests are shown in the next graph. And there are two major forest areas to keep in mind. First is the forest areas around the Equatorial belt. These are the rainforests. The Earth’s climate is of course providing most solar radiation at the equator. It’s the warmest at the equator. The land eh, is heated. Air masses rise and provide continuous rainfall or heavy rainfall, I should say, in the equatorial regions of the world. And that provides the climatic base for the three great rainforests of the world, the Amazon, in South America, the Congo Basin in Africa, and the great rainforests of the Indonesian Archipelago in Southeast Asia. That’s the band around the equator. Then you see the other major forest region which is in the high latitudes. The boreal forest for example in, across the vast Eurasian land mass, and across Canada. Many of these forests are being threatened especially today the rain forests. Because these are all areas where populations are encroaching for a variety of reasons. Either to clear the rainforest to make way for pastureland and for cropland. Or poor people encroaching on the forest for fuel wood and for other goods and services that they can procure from the forest. But sometimes in such great numbers that they are deforesting in an unsustainable way. This pattern of where the cropland is and where the forests are, you can see is very deeply rooted in the ecological conditions. The climate, including temperatures, rainfall, the topography. The shape of the land, whether it’s steeply sloped and not possible to farm or whether it’s flat land in plains much easier and more productive to farm. Whether irrigation is feasible, because there is ground water, or rivers nearby that can be used for irrigation. Whether the soils are adequate. And the range of soil types depending on the the underlying geologic conditions also shape the farm systems. It’s worthwhile for us to take one deeper look in one part of the world, to see the geography shaping the farm systems, shaping the societies in effect in these agricultural regions. And, and that’s in Africa, where we can see very, very clearly how the distinctive characteristics of climate cause very distinctive farm systems and very distinctive economic results as well.

1023This is a map. Quite a beautiful map, I think, of the various farm systems in Africa. 14 major agro-ecological zones. Each one a specific kind of farm system. Perhaps it’s a good idea to decipher this map in, in stages starting at the equator. In the large green area, right it, at, at the center of the African continent. That’s the Congo Basin, that’s the great Congo rainforest. And rain forests are very particular when it comes to agriculture. Very difficult to farm, often. soil, nutrients are bombarded by heavy rainfall. If trees are cleared as is sometimes done to try to make farms, it often is the case that the soil nutrients which were up in the trees themselves rather than in the soil are quickly depleted and it turns out that the land is not suitable for intensive farming. And not even suitable for pastoralism or for livestock management. If you, we move from the equator we come to different farm systems graded, to a very important extent, according to how much water is actually available through rainfall and other other resources. Take a look at West Africa, for example, just above the Atlantic Ocean. And right along the coast, the entire coast, of West Africa is a still wet, though not rain forest region which is ideal for tree crops. For the cocoa plantations of Ghana, the rubber plantations of Ghana, Benin, Togo and Liberia. So this is a climate not of annual grain crops but of tree crops because of its humidity and its ideal circumstances for tree crops. Move north of that, away from the equator. You move into an environment where there is a rainy season. But, the farther north you go into the northern hemisphere. The drier is, are the conditions and the shorter is the rainy season. So, just north of the rubber and cocoa plantations, one finds what is called the root crop systems. For example, where cassava is grown and other tubers and root crops are grown in this relatively wet environment. But not wet enough to support cocoa trees or rubber trees. Move just north of that and then you’re into a grain belt. For example where maize or in the United States we call it corn is growing. This is now a, a part of Africa where instead of the year-round rainfall of the equator, you have one rainy season which may give a growing season of 150 days for one crop of maize per year. it can be rather productive if the topography and the soils are right, and if the rains are good. It can be a disaster if it’s a year of bad rainfall. And there is relatively high variability in these places. And in the African context, at least, relatively low use of irrigation. So a dependency on the variation of the rains. Now as you continue the march north from the equator, towards the north pole, the rainy season gets shorter and shorter. So after the band of grain growing region is another farm system and this is a farm system that mixes crops with livestock. The livestock to graze on the grasses, the crops to capture a short growing season. But now it has to be crops that are pretty resilient to short rains and even to drought. Those are sorghum and millet for example. So, we have passed through the maize region into the sorghum and millet region combined with more livestock. And this is the so-called agro-pastoralist zone. Because it’s both agriculture and pastoralism. Move a bit north of that and you move into a range that is an all pastoralist region. And these are places often of nomadic populations such as the Tuareg in Northern Mali. The population densities are very low. The populations are nomadic, because they have to follow the rains. And as the rains move throughout the season the grasses spring up for short periods of time in these dry environments. And the animals better be where the grasses are so the animals move around. Also the  nomads move across national boundaries. No one told the animals and no one told the rain this is Mali, this is Chad, this is Niger, stay in your place. And these artificial boundaries that have been put first by the imperial powers. And now as part of our political world. Have wreaked havoc on the pastoralist traditions that find themselves cut off from their family, neighbors, and their grasslands across a political boundary that has no ecological sense. Now, consider one step north of the pastoralist lands and in you’re in the Saharan Desert. We have, er, I should say Sahara because it’s the desert. because, so, in, in, in fact, you’ve entered the desert. And we have seen the graded transition by latitude band from a rain forest to a tree crop region, to a root and tuber crop region, to a grain region to a agro-pastoralist region to a pastoralist region and then to the desert. It’s not surprising this is complicated. It’s complicated for countries to manage this diversity it’s complicated when populations like pastoralists need to move across boundaries. It’s complicated to get international agreements on what to do about issues of climate, or energy, or food production, when we see these strong variations of farm systems across the regions. It’s very hard, often, for people to speak with each other and to understand the problems and the stresses that are unfolding. This is one of the reasons why the world has failed to comprehend challenges like the crises of the Horn of Africa and the ongoing crises of the Sahel. These are agro-pastoralist regions, or in some cases, pastoralist regions only. Very poor. Very much dependent on rainfall. Suffering the burdens of climate change, instability of rainfall, rising populations, falling trend in total precipitation, increasing hunger. And, as a result, increasing instability and violence We need to understand these farm systems, where they are, how they vary around the world, if we are to achieve sustainable agricultural yields that can feed and keep populations healthy in the future.

Lectures / Readings

Sustainable Food Supply and the End of Hunger I

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Malnutrition

We need to consider one of the most complicated and unsolved problems of sustainable development. How are we going to feed ourselves? It’s an age-old problem, it’s been with humanity for a long time before, but for quite a few decades. This is problem that many people thought was already solved with the great breakthroughs in food productivity. In increasing farmland, increasing yields, it seems that food production would inevitably stay ahead of The growing world population. Now we have some serious doubts. Not only are we coming to realize how badly fed the world population is in certain ways, but how many real threats there are ahead. That is our challenge. 1011We can’t say we haven’t been warned. The warnings have been with us for more than two centuries. They started, as I mentioned, with Thomas Robert Malthus, who in 1798 in his Principles of Population posed the basic question of how food production can stay ahead of a growing population. When Malthus wrote, there were around 900 million people on the planet. Now with 7.2 billion people, an eight-fold increase, the challenge is with us again. In fact perhaps in an even more complicated way than Malthus imagined. Because now, we come to understand that not only is the world not feeding itself but in a healthy and fair manner. But there are many, many obstacles that lie ahead. Let’s start with the question of, what does it mean to feed ourselves in a healthy way? And we can ask that by looking at the question of malnutrition. Malnutrition is a pervasive problem on the planet. One can argue, I think convincingly that perhaps 40% of the world’s population, 40% is malnourished. In one way or another. But to understand that, we have to understand what we mean by malnutrition. Now, one thing that jumps to mind, of course, is hunger and undernourishment. Undernourishment in it’s most direct sense is, simply not taking in The calories that are needed for daily activity and daily survival. Hungry people feeling the pangs of hunger and not having enough energy for more than mere survival and in some desperate cases, not even that, remains a problem afflicting hundreds of millions of people.

In the world. There’s another kind of under nourishment. That is a bit less visible. And that is a category sometimes called hidden hunger. The calories may be there. But the micro-nutrients nutrients such as vitamins and. Particular fatty acids and other components of food are not present in adequate supply so that people are unhealthy and perhaps chronically disabled as a result of bouts of micro-nutrient deficiency. There’s a third kind of malnutrition, which has become An epidemic in many parts of the world, especially the richest countries. But also many middle income countries. And that is malnourishment in excessive consumption of calories. We have an obesity epidemic underway in the world. And it’s estimated that roughly one third of all adults in the world are overweight. And perhaps around 10 to 15% are obese.1012

When you add it up, the numbers are staggering. Roughly speaking, we can say that Between 800 million and a billion people are on the planet are chronically undernourished in the sense that they do not get the daily energy intake in their diets to be healthy and to be satisfied with the, what they’re eating. But another billion people, who are not counted in the hunger category, are in the hidden Hunger category. So, roughly, 1.8 to two billion people are undernourished either in the direct sense of not enough energy intake. Or, in the sense of micro-nutrient deficiencies. And then, the estimates vary on obesity. But it is certainly well over a billion people who are overweight, and several hundred million, perhaps 700 or 800 million adults who are obese. You add it up and it’s plausible to think around 2.8 billion people on a planet of 7.2 billion people. Are malnourished, about 40% of the population.

1013We have a food crisis. It varies in different parts of the world, sometimes it’s hidden, sometimes it’s the wrong kinds of foods, sometimes it’s simply not enough food. But any Serious, Focus on the sustainable and secure food supply for the world, has to view the crisis in all it’s dimensions. From those who lack the basic caloric intake to those who, in grade of happiness, often are suffering. From obesity, and from all of the massive ill effects that come from that. Let’s have a look at where these problems are distributed. Under nourishment, is concentrated in tropical Africa, and in South Asia. So we see in Tropical Africa, especially in Central and Southern Africa, that more than a third of the population is undernourished.

1014This means simply not enough calories, or by some measurements, not enough calories and proteins needed for basic sustenance. And in south Asia we see that the proportions of chronically under-nourished are between a fifth, 20% and a third, around 33%. Serious levels of under nutrition and fortunately in the rest of the world, lower levels than that. In the high-income countries, very little under nutrition in that sense, though massive problems of malnourishment when one considers the problems at the other end of the spectrum. When children are undernourished Of course they suffer a massive disability in their growth that lasts a lifetime. If the undernourishment effects them in the critical growing stage in the early years of life, and we measure that under nutrition with several different concepts. But two are especially important. One is stunting. Stunting means that a child is undernourished to the extent that the child is very short low height.

1015That is for age and the standard is measured against a Regular distribution for normal population of height by age. And then children who are far to the low end of that scale, more than two standard deviations below the norm, are considered stunted. And stunting, of course, reflects the Inadequacy of dietary intake, but it often also reflects chronic infection. Worm infections for example that where the worms take the nutrients that should be going to the young child, or other kinds of infections That mean that the child is shedding nutrients, maybe through bouts of diarrhea or that make the nutrients not bioavailable to the child, they can’t be metabolized while the child was sick. So, when we see stunting, we usually are. Looking at, circumstances of chronic, dietary undernourishment, combined very often, with repeated bouts of illness. And the stunting, we see is most severe, where we, normally find it tropical Africa. And the highest stunting rates in the world in South Asia. Especially in India which overwhelmingly has the largest numbers of young children who are stunted. The second concept for children is even more urgent and that is wasting. Wasting is low weight for height. So stunting is a chronic condition that means that the child doesn’t grow.

1016Wasting is when the weight is even less than it would be for that low stature.  It’s often a sign of acute Undernutrition. Life-threatening undernutrition. The kind of undernourishment that one sees in a famine, in a megadrought. And then one sees children wasting and there needs to be an urgent rescue through therapeutic foods and and often em, emergency procedures to help keep the children alive in those circumstances. When we talk about undernourishment in general, we tend to separate it, and need to separate analytically, the chronic undernutrition, which is the day in, day out hunger.

1015That does lead to the stunting from the acute episodes of undernutrition that come from disasters, from displacement of populations, from droughts. And when those acute episodes occur, not only is there massive suffering, there can be massive death. From the undernutrition. In the worst cases from starvation itself. In other cases from diseases which take advantage of the undernutrition and the immunosuppression that comes along with the undernourishment. There’s also another massive reason for suffering that comes with acute episodes of of hunger that follow droughts, and other disasters. And that is the conflict often follows on.

1018Have a look at a map for the Spring of 2012. When they were two regions of Africa. Both battling drought. Looking at the map which is a map that is Used to measure emergency situations we see. The acute food insecurity both in west Africa and in east Africa. There were indeed large population movements, resurgent violence. A civil war broke out in Mali, not only for the reasons of hunger, but hunger stokes these conflicts. And so this is another scourge that accompanies food crises. When we turn to hidden hunger, it of course also, is lurking in populations where the visible hunger is also seen. Now you’re looking at a map of, an estimate of the hidden hunger of micro nutrient deficiency. Which kind of nutrients are we talking about? Vitamins such as vitamin A or vitamin B in several of its forms. Iron, iodine, zinc, folates. All crucial micronutrients that when not adequate in the diet can lead to Terrible health disabilities, death in extreme cases, and also, very great dangers for child birth. Mothers who don’t have enough folates during pregnancy often give birth to children with devastating defects. And this is a Pervasive condition that afflicts the poorest countries.

1019We see again, India and South Asia, much of tropical Africa the Andean Region. Some of the other countries of Western Asia and of Southeast Asia where there is considerable micro-nutrient deficiency. Unfortunately, the knowledge and the data of the hidden hunger are themselves hidden. There are not precise estimates known for many of these  micro-nutrients. In terms of where they really are seriously lacking in diets. The next map shows you an estimate for vitamin A deficiency. Again regions of the world that you would expect. But a larger area of the world. Even including many middle income countries in Latin America, and also China. Now let’s look at the other end of the malnourishment spectrum. One that also is causing a tremendous amount of morbidity. In other words disease. And premature mortality. And that is the obesity epidemic, that is sweeping much of the world There have been enormous increases of obesity in the last 30 years. What is obesity? Obesity is a specific measure the typical definition is to use the so-called Body Mass Index, a person’s weight in kilograms is divided by the square of the person’s height measured in meters. And that BMI, the body mass index, if it’s over 30, is considered obese, if it’s over 25 it’s considered overweight. And by that measurement we have a massive epidemic of adult obesity. In many of the high income countries, 30% or more, in the United States and in some other high income countries. Why?

Partly it is the total amount of caloric intake, partly it’s the type of calories being consumed often. Carbohydrates trans fats and other foods that are known as having high glycemic indexes that they’re easily, the sugars are easily metabolized. Part of it is the relative inactivity. In our new urbanized environment, where people sit, maybe watching television for hours at a time. A combination of too many calories, the wrong kinds of calories and physical inactivity. What to do. A starting point is to combine The food growing challenges with the nutritional science. What should be grown? What should people eat? And here breakthroughs in nutrition science are giving us better indicators. One of the leaders of modern nutrition, and rethinking what is wrong With our diet is Professor Walter Willette.

1019aA chairman of nutrition at Harvard University. And he has proposed the right kind of food pyramid as it’s called shown here which depicts the kinds of foods and the relative Frequency and amounts of those foods that should be eaten. And just to indicate very briefly what the findings of modern nutrition are because they’re important. It tells us that our diets as they evolved with the fast foods of The high income countries have become very imbalanced the source of, this, pandemic of obesity and, overeating. And what is needed is diets that are rich in vegetables, in fruits, in vegetable oils so called unsaturated fats which are healthy. As opposed to the animal fats and the industrial fats, the so called trans fats which can be very dangerous for health. And when grains are eaten, they should be eaten as whole grains. And so the dietary mix is. Quite different from the diet. Of the high income world,which is heavily concentrated in the wrong kinds of fats in in refined grains rather than in whole grains and in a very heavy meat-based diet which has its own Great difficulties for health especially. A large amount of beef eating. I mention this because it’s going to have a, big consequence when we discuss what kind of agriculture system, should be consistent with the kind of diet. That is healthy for people. Of course this kind of food pyramid viewed from the perspective of the poorest countries is a dream. How can we get from where we are, not even enough calories in the day, to this kind of balanced diet that can be healthy, and provide not only the macro caloric intake and proteins, but also the micro nutrients And the balance of different food components conducive to health. The world is in increasing stress when it comes to the food system. More mouths to feed, a rising demand for meat products which amplifies the demand for the grains to feed. The animals that are being consumed in larger number. All combined with environmental threats that are undermining the stability of the food production itself in many parts of the world. We’ve already gotten, a taste of it if I could put it that way in Rising food prices that are a major challenge for poor people in the world. If you look at this graph of food prices since the late 1970s, you see that for all of the major grains, the staple grains maize Rice, wheat and soy beans prices were falling from the 70s until the end of the 20th century. But since the beginning of the 21st century, the price of food has been rising and rising sharply. For wealthy people, this is a, an inconvenience, a discomfort. For poor people, whose diets consume a much larger part of the family income, this is more than just an annoyance or a hindrance. It is a profound threat. To their well being. We see Engel’s Law in operation here. The idea that, for poor people, the food consumption occupies a much larger share of the total household income, and therefore rises in food prices Can be very devastating for households that buy their food from the marketplace. So here we have it, 40% of the world still not properly nourished. And a food supply under threat, yet facing rising demands. From growing populations and from parts of the world with higher incomes, putting even more intensive demands on the food supply. Huge puzzles, what can we do about it. We have to look closely now at how food is grown. Where it’s growing, what the threats are, what can be done about it.

Lectures / Readings

Growth within Planetary Boundaries IV

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The Case of Food

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.