WHRC's Sustainable Science Speaker Series - Dr. Eric A. Davidson on Agriculture

We're kicking off this talk or this series with my talk on sustainable agriculture. And some of you may have already seen the first part of my title once before. And I want to emphasize there are about 6 billion people on the planet, or 7 billion people on the planet. Not 6, but probably about 300,000 or so in India are vegetarians and maybe a few hundred thousand elsewhere. So we're talking about over 6 billion carnivores. And our choices in our dietary habits have as much to do with our sustainable agriculture as what farmers do. And that's one of the points that I want to drive home from the beginning, and I'll try to be making it at the end. So the more of us there are and the more meat we eat, more manure will happen, literally and figuratively. But before we go into agriculture, let's talk a little bit about what we mean by sustainability. Some of you who perhaps followed some of our activities may be aware that a couple months ago we had opportunity to honor Dr. Gro Harlem Brundtland, former Prime Minister of Norway, with a prize, the Huntington Prize, named after our former chairman of our board. She was the person who chaired the Brundtland commission in the 1980s that established, pretty much established, the notion of sustainable development, gave us this definition that it is development that meets the needs of, of the present without compromising the ability of future generations to meet their own needs. So in the case of agriculture, you could imagine that would mean growing crops without allowing soils to erode away, become full of salt or toxins, and not to change the climate so that those crops won't prosper in the future. When we get to talking about sustainable agriculture, we need to think about a number of things simultaneously, especially if it's part of sustainable development in the developing world. Because While there are 7 billion people on the world, there are currently nearly 1 billion who are malnourished. There's about 1 1/2 billion who live on about $1.25 per day. On the other side of the coin, there's another one and a half billion that are overweight and in health risk due to their weight and heart disease and diabetes and that sort of thing. So it's a very uneven distribution. But for those who are the poor and malnourished, part of sustainable agriculture needs to include increased production and increased income. They need to be able to adapt to the climate change that has on already happened, that is already in the pipe. Even if we were to stop fossil fuel emissions tomorrow, there is already climate change happening. And that Is already affecting their agricultural practices. And the agriculture itself is one of the sources of the greenhouse gases that is contributing to climate change. So we need agricultural approaches that will reduce greenhouse gas emissions. And throughout much of the world, water is one of the limiting resources for, particularly for agriculture and, of course, the competition for land, for production of food, and now fuel with biofuels and for native ecosystems. So sustainable agriculture needs to protect the environment and the ecosystem surfaces that we depend upon, stabilizing climate, providing water in addition to providing food. So those systems need to allow productive and resilient livelihoods of people and the ecosystems around them. They need to contribute to a secure and sustainable and safe food system, to provide adequate food and nutrition and to allow the rural poor to escape from their poverty and remain out of their poverty. Now, it wouldn't be me giving a talk if I weren't talking about nitrogen at some point in the talk. And it turns out that nitrogen, the development of synthetic fertilizer, Nitrogen fertilizer, Just looms huge in the history of our agricultural development and where we are today. And actually, the discovery of the ability to take nitrogen gas in the air, 80% of the air that we breathe is made up of nitrogen gas. It's harmless. But to combine it with hydrogen gas under high temperature and pressure to produce this thing called ammonia, which can then be converted to nitrate, Is what really revolutionized our agriculture. It wasn't done purposely for the sake of agriculture. It was actually done by German chemists who were looking for ways to provide munitions for Germany in the beginning of World War I. They were concerned that their source of nitrate for munitions, the N and tnt refers to nitrate, was from Chile, Some deposits in Chile. And if they didn't have shipping lanes, if they couldn't maintain shipping lanes during the war, they would run out of munitions. And so they ended up inventing this process. It wasn't until after World War II that the swords got turned into plows, so to speak. And they actually started producing synthetic fertilizers that could be used in agriculture. And it's really this tremendous increase in use of synthetic fertilizers that permitted the human population to increase as much as it did. These are thousands of millions of people. In other words, 7 billion people. And this slide's a little out of date. We're now above 7 billion people. So this absolutely transformed our society. If it hadn't been for that, what would have happened? It's hard to say. Either we would be. There would be fewer of us, we would be less healthy and probably would have had to clear more land in order to produce the agriculture products that we have produced. I've also showed this before, but I think it's the most efficient way of being able to explain why that is a problem. I mean, it's great that, on average, we're better nourished, but unfortunately, not all of that synthetic fertilizer ends up where we want it to. So if we take 100 units, it doesn't matter, and then remain on the field and get recycled back into the soil, and then some of it in processing, the food is lost at various stages, and then nearly half of that is lost because of the way we waste food, particularly in the developed world. So at the end of this chain, only about 14 of those units of the nitrogen that the farmer applied onto the field ends up in the human mouth. And many, many of those other units end up inadvertently released into the environment, where it's causing other factors. And this 14 out of 100 is true if you're a vegetarian, if you're a meat eater, and there are more meat eaters now than there used to be. As the human population increased, the livestock population, or amount of meat consumed increased even more rapidly. So we are eating more per capita, on average, than we did even as recently as 1950. So using that same chain of logic here of applying the fertilizer to the field, how it goes into the crop, but now instead of being fed to humans, it's fed to animals, Animals, animal ration. And there's a huge wastage there. This is where the manure happens, part comes in. And so a smaller fraction actually is harvested from the livestock. And again, there's more wastage. And so only four of those hundred units actually go to nourish human beings. So if we think of the agricultural system like a leaky pipe, so we have inputs in one end of the pipe. It might be synthetic fertilizers, it might be natural nitrogen fixation, like soybean crops are able to take nitrogen out of the air through the nodules in their roots, and they fix nitrogen, it might be through manures or compost. Whatever the source is, we input nitrogen into the system, we produce some crops that we consume directly. We feed some of it to animals into animal production systems and consume some of that. But both of these pipes, these metaphors for producing crops and producing livestock meat, are leaky pipes. And they leak out different kinds of gases that go up into the atmosphere, and they leak out different forms of nitrogen that go into the groundwater and to surface water, where they have unintended consequences. Unintended consequences such as contributing to smog haze. One of the forms of nitrogen does that. Another form falls back down onto forests and onto lakes and it acidifies them in excess. Acidification can disrupt those ecosystems. Another one of those forms is now the major remaining ozone depleting substance. We've done a pretty good job through the Montreal Protocol of reducing what they call chlorofluorocarbons, which were until recently the primary reason for the hole in the so called hole in the ozone in the Antarctic. Those are going down thanks to our foresight in the Montreal Protocol. Now nitrous oxide is the remaining main source of human caused reduction of the Arctic ozone. That same gas is also a heat trapping gas and contributes to global warming. And there's the iconic polar bear as a symbol of global warming. And they also contribute to eutrophication. Growth of algae, in this case probably perhaps a red tide noxious algal growth that can either be direct influence on human health or indirectly through using up the oxygen as these algae decompose and killing fisheries. And that is a global phenomenon. This is a map of each red dot is a place in the world where there is one of these anoxic or hypoxic low oxygen conditions due to excess algae growing in the in the estuary and as a result affecting the quality of the water. Sometimes noxious odors, usually a decline in fisheries and shellfish. And it's throughout the world. But of course, as you might guess, it's concentrated in Western Europe and along the Eastern seaboard of the US but growing increasingly common in China. And the fellow who put this together, Bob Diaz, has said that probably it underestimates the incidence because of lack of data. So where there are not red dots doesn't necessarily mean there aren't hypoxic zones, but it means there aren't good data. Another impact of it is that some of the leaking nitrogen goes into our groundwater in the form of nitrate. And this is a map of the dark areas are aquifers that have nitrate that in some cases exceeds EPA recommendation limit for human consumption of 10 milligrams per liter. In many cases it is at least halfway there. And so that there's something like about a half a million Americans that use private well water that exceeds the EPA women and another over a million that are drinking well water that gets close to that. And our agricultural system is no longer integrated. We no longer live where there's an old McDonald with a quack quack here and a moo Moo. There, everything is separated so that we grow our grain with lots of nitrogen fertilizer. In Iowa, a lot of that leaks down the Mississippi and contributes to this what we call a dead zone, one of those hypoxic areas with overgrown algae in the Gulf of Mexico. We then ship the grain off to North Carolina, where many years ago North Carolina established some very lax environmental laws in order to encourage hog producers to come in there. They've since tightened up some of those laws, but there's still a predominance of hog production down here, which results in ammonia emissions that deposit on Pamlico Sound and causes water quality problems there and on noxious emissions, coastal eutrophication. And that manure now is too heavy to make it economically viable to ship it back to where it could be used as a fertilizer. And so it gets spread in the forest or it accumulates in lagoons until it gets inadvertently washed away at midnight. So these are the results of having an unsustainable agricultural system where we aren't reusing the nutrients that we apply on the system. Well, as I said, in general it's been a good thing because we are much better nourished and better off than we were even a generation ago. This is a picture of a German family with everything nicely, neatly laid out for what they would eat for a week. Here's an American family doing the same. A little more fast food, but still a lot of food. But all jokes aside, the sad part is here's the same thing for a Somalian family. The food that they will be eating for a week. And in this case, it's not simply the case that they're eating a lot less food. If you look in the background at the landscape that they're in, you can see that they are harvesting more nutrients from the land than they can put back in. They can't afford fertilizers. They don't have livestock that are well nourished, that are producing manure that has the right combination of nutrients for growth. They are mining the soil of nutrients and as a result you end up with a vicious cycle. Poor agricultural management results in loss of those nutrients. Also loss in biodiversity of the animals and plants, in the ecosystems, results in environmental degradation that results in declining crop productivity, so declining health and well being of the people. So that's less labor for agricultural management. We have to somehow break that cycle. So we have different sorts of problems of sustainability, whether you're talking about the developed world or the developing world. And here is a map of Africa, two maps showing changes over just a decade. And the red areas, in kind of an olive green, are showing the areas where there are more nutrients being harvested in the crops than is being put back onto the soil in the form of fertilizers and manures and compost. And that's obviously not sustainable. That is degrading these systems of the nutrient capital. You can't be pulling capital out of your bank all the time and still expect to be able to earn interest. Well, in spite of the problem of Africa, much of the rest of the developing world, particularly China, is doing a lot better. And their standard of living is going up and they're eating more and more meat. So in the developed world, we eat somewhere between, on average, 70 to 80 kilos of meat per year. In the developing world, the average was around 20 or 30, and it's starting to move up to around 40 now that there's a good deal more prosperity in Southeast Asia and a few other parts of the world, Latin America, that's per capita, if you take these numbers and multiply it by the number of people, you see that in the developed world, well, there are not that many of us, and our population isn't increasing very much. We are still eating more and more meat. So this isn't going up too much. But in the developed world, even though they're still eating about half as much per person on average, there are so many more Chinese and Indians and all the other countries in the developed world that they have overtaken us in terms of total meat consumption. They've also overtaken us in terms of total greenhouse gas emissions, total nitrogen fertilizer use. But are they doing it in a way that's sustainable? And I'm going to borrow some slides here from Jason Clay from the World Wildlife Fund. He put together some slides I thought were really compelling. And I figured as long as I give him credit for them, it's okay for me to share them with you. What's coming? Population is going to increase 2 to 3 billion by 2050. Income should increase, which is a good thing. But it also means that there will be more people demanding more nourishment. More meat consumption will double. Consumption of animal protein will increase even faster, and 70% of the people will live in cities. That's as many of the people, as many people as are alive today. So take all the people throughout all the rural areas and cram them into cities, and that's what's going to be in cities in 2050. And where is their food going to come from well, agricultural. This means that agriculture is our biggest threat, or at least one of the biggest threats to demands for managing natural resources. Demands for land. Why? Because in order to produce more food, there's pressure to clear more land for agriculture. Fire is commonly used as one of the mechanisms for clearing land. We do work in Brazil where we are working on this kind of slash and burn agriculture. Also on finding alternatives to means converting landscapes to highly managed landscapes. As you can see with this rice padding. Now in some ways this might be a good thing in that certainly those terraces are helping to slow down soil erosion. It looks like they have a system here for managing water fairly efficiently. But certainly it's a very made over ecosystem that's not going to have much in terms of diversity of different types of life. That's what is needed for producing large quantities of grain. And in some cases those excess nutrients don't go where you want them to. They end up with fish kills like this and another impact of that type of development. And if we have to go to high production systems, mono crops, then that means we lose natural defenses against insects and have to come with another way of battling them. And so it becomes an arms race as to how to figure out how to keep ahead of the insects as they adapt to different kinds of pesticides. And if it's not done right, it can lead to gullying. A huge gullying. And this isn't just today in the developing world. That is true, that is happening today in the developing world, but it happened a century ago in this country when we were a little more than a century ago, when cotton was king in the southeast. In fact, did you know that the Lincoln Memorial now stands on land that was sediments washed down the Potomac river due to gullying like this upstate in Virginia? Well, another aspect is how much water all this agriculture uses. And here's just some example of some products. And let's take, take a look at this Quarter pounder hamburger. What it requires, it requires 8 ounces of hamburger, which is going to need somewhere between 3,000 and 15,000 liters. That's about 1,000 gallons to 3,000 gallons of water to produce one bloody hamburger. And where in the world is there water shortage? Well, lots of places in the American southwest, of course, the Sahel, most of Australia and much of China and India where there's huge demands on agriculture. So the red areas are places of less than 500 cubic meters of water available per person. Where in the world are we growing crops? As you can see, it's American Midwest, most of Western Europe, China, India, and a good deal of the cerrado and the pampas in South America. And that is about 33% of the land. There's another 5% in deserts, another 18% in mountains, lakes and rivers. Another 2% in cities. To grow the food for all of these people. Oh, excuse me, another 12% in parks. I got ahead of myself. To grow the food for all these people. Some estimates are that we're going to need another 24% of the total land area to increase the agricultural area to grow that food. That's one option. Another option is intensification of agriculture where we have land, and probably end up a combination of both. But you'll notice that this leaves a very slim wedge left for any other type of land use, for any other possible conservation of land for native ecosystems. Well, farmers are proud of the fact that they feed a lot of people. And it's a good thing for us. We can be scientists, we can be artists, we can do all of the other things that we enjoy doing, providing health care and education, because there are people out there who, each one of them is feeding hundreds of people due to this agricultural system that we have. Is that an agricultural system that we can sustain? And what is the future of the systems that we will have? Well, we have to shift our thinking, I think, from maximizing crop production. So it isn't always the total, the biggest acreage, the biggest yield you can possibly get per acre of land. But we need to optimize numerous things. What's the most amount of food that you can get, for the least amount of pollution, whatever kind of pollution that happens to be, or destruction of native habitat that happens to be. And I want to show you a six minute video that I think explains this extremely well that comes from the Commission on Sustainable Agriculture and Climate Change. Bear with me just a moment.

The state of our Earth can be defined by how much climate change it experiences and by the total amount of food that is available through agriculture and trade. The world has increased its agricultural production over the past centuries. At the same time, it has undergone climate change partly as a result of activities related to agriculture. In 1850, the climate had not yet begun to change due to human activities and food production was low. After 1950, world food production rose dramatically. Before 2000, we began to see evidence of human induced climate change. Our climate will continue to change given the greatly increased levels of greenhouse gases already in our atmosphere. Extreme events such as high temperatures, droughts and floods are already more frequent and severe. Faced with growing Demand for food, fodder and bioenergy crops. Many agriculture systems deplete soil fertility, biodiversity and water resources. Many regions exhibit large gaps between potential and actual crop yields. The path our world takes in the future depends on the choices we make. To be sustainable in the long term, the world must stay within certain limits. This frontier curve represents the maximum amount of food we can grow under a given climate. If we do the best we can on every bit of land. It declines steeply under extreme climate change which will have an adverse overall effect on agricultural production in the next few decades. Climate change will bring us toward and perhaps over critical food security thresholds in many regions. Areas currently suffering from food insecurity will be hit worst. This curve represents how much food we need to ensure everyone on Earth has adequate nutrition. The world's population will increase to around 9 billion by mid century. It curves up under high climate change as we will need more food to make up for greater crop losses due to climate variability and pest outbreaks. This curve represents the effect of increasing food production on climate change. As we clear more land for crops, apply more artificial fertilizer and have larger livestock herds. The climate impact Already nearly a third of current climate change increases. A sustainable future must be located within the space defined by these three limits. This is the safe space. Today, on a planet that grows sufficient food for all, a billion people go hungry. Another billion overconsume increasing risks of chronic diseases. One third of all food harvested is lost or wasted. Food waste in industrialized countries is almost as high as total net food production in sub Saharan Africa. We are not in a safe space. This is where the world is heading. By mid century, unless we make some big changes, hundreds of millions will remain undernourished and we will be perilously close to the limits of food production. We can take actions to enlarge the safe space and move the planet within its boundaries. First, by eliminating waste in the food chain, increasing equity in access to food and shifting to vegetable rich diets that demand fewer resources, we can reduce the amount of food we need. By investing in agricultural research and development, we can increase the amount of food we grow. We can also expand the safe space by adapting cropping systems to hotter climates. Through innovations such as improved crop genetics and careful matching of crops to environments. Ever higher average global temperatures will result in less greenhouse gas emissions are drastically reduced Across a wide range of human activities. Agriculture must do its share. By carefully intensifying production on existing agricultural land, we can reduce on site emissions and reduce deforestation. Sustainable intensification will Help close the food yield gap while reducing emissions per unit of food produced. By reducing greenhouse gas emissions across all sectors, not only agriculture and forestry, we can slow down the onset and potential impacts of climate change. By implementing all these actions together, it is possible for Earth to survive and prosper in the long term, even with a substantially larger human population that it will carry in 40 years time. We must transition the world into to the safe operating space through collective decisions and actions. Our most powerful actions for meeting food security needs. While reducing environmental impacts, improving crop yields, reducing waste, changing diets, adapting to climate change and reducing agricultural greenhouse gas emissions, we can achieve food security in the face of climate change. Learn about key actions for moving into the safe space and explore successful innovations from around the world.

So there's some things there that I'm sure are controversial. The first one that probably isn't controversial is the issue of waste. I think probably everybody can agree that dealing away, trying to avoid waste when they talk about one third of the food being wasted is something that we can all agree is a low hanging fruit. Where exactly is that waste happening in Europe and North America? Most of that waste, here's the 1/3, by the way, 33% is at the consumption end. After it's delivered to us, we leave it on our plates. So there's tremendous opportunity there for reducing waste. But in sub Saharan Africa you notice that there's hardly any waste there, but the real waste occurs in, in the agriculture and post harvest period. And that's also true in other parts of the developed world. And that's because so often the crops are destroyed by pests, fungus or rats. But there are inexpensive and appropriate technologies now to improve storage of agricultural crops in rural areas. And also even the cell phone is making a huge difference in this, in that farmers can now find out when the next truck is coming to buy their product and know whether the next truck that's coming is what price they're going to offer and whether it's worth it for them to take that price or maybe wait for another one and try to get a better price from someone else. Without that information, they don't know whether it's worth it to store or to sell. But by providing that information, they can make more intelligent choices and make more incomes for their families and probably reduce wastage. Now, you heard them talk about intensification, intelligent intensification. And for some people in the, some groups in the NGO community, there's suspicion that intensification is a code word for industrialization. And industrialization is often used Pejoratively, we think of big farms, monocrop agriculture, as heavily reliant on fertilizers and pesticides. That certainly is one form of intensification, and it probably is a form of intensification that will be with us for quite some time. But when we talk about intensification, what we really mean is learning about timing and dosing of nutrients so it matches the crop demand. It's more expensive to put many small doses on than it is to put one big dose, but in doing so you lose less because you're matching the dose with the crop demand. Understanding cycles of insect pests and weeds, that's been talked about for a long time under so called integrated pest management. It doesn't rule out the use of pesticides, but it uses them very judiciously at the time when they're most effective and it looks for alternatives for using them as well. Tillage practices that prevent soil erosion and conserve organic matter and soil water. There are now, it's quite common, the so called no till agriculture machines that drill the seed down into the soil. You don't have to turn over the soil, you just drill the seed down into the soil. And that avoids a lot of the soil loss and avoids the decomposition of organic matter. But there are trade offs. But there are trade offs. If you don't turn over the soil, then you're not digging up the weeds. And so you save the soil in terms of less erosion and perhaps less loss of organic matter, but you might become more dependent on herbicides. So I think we have to recognize that the moment you start growing a crop, the moment you've cut down a forest or plowed a native prairie already, talking about compromises. So there's always going to be trade offs. And the important thing is to have the knowledge to understand what those trade offs are. It also means inputs in materials, capital and labor. So you have to have inputs of nutrients. It can come from manure, from compost, or from synthetic fertilizers. And it really depends on the situation and on the availability of them and the affordability of each. There are some places in Africa where the nutrients are so depleted that there are many agronomists that think that we initially need an investment of synthetic fertilizers in order to recuperate the capacity of the land to produce any of these other organic forms of compost and manure. But eventually those need to be integrated into the system. Seed varieties. You heard them talk about genetically improved seed and of course that's a real flash topic among Many people. As to whether we're talking about traditional breeding of plants that we've had for centuries and millennia. Actually, all of our crop plants are plants that probably could not survive on their own without us taking away the competing weeds. So we modified the genetics of all crop species through traditional breeding practices. Now we have the technology to modify them through molecular approaches. And of course, that's very controversial, but in some cases, it provides seed varieties that are resistant to drought or to salinity or to heat stress instead. So these are arrows in the quiver that might need to be considered in some of those situations. Infrastructure for irrigation and water conservation. I don't necessarily mean those big circles that you see in the Midwest when you fly over the central post irrigation system. That's one way of doing it. But there are many other types of harvesting, natural rainfall and funneling it into the area that you want it to be. But it does require investment of some materials, capital and labor and knowledge. This is just an example of some colleagues that I've worked with in their work in Africa showing the difference of adding no fertilizer with a yield of 1 ton per hectare of maize. In. In Iowa, it's probably more like 10. And with a modest increase of fertilizer, they can triple that. And these are rates that are probably about a third of what the Iowa farmer will use and probably about a sixth of what Chinese farmers are currently using. Well, moving back to the developed world, here's an example of some research that was done and reported on in one of the conferences that we sponsored, where in the state of Iowa there was something similar to what we have here in Massachusetts of determining allowable loads of nitrogen going into a water body. So the state had determined what the allowable amount of nitrogen going into this Cedar Creek watershed was. Of course, it wasn't being met. So some scientists from the USDA and universities said, well, let us run your farming operation for a few years and see if we can figure out how to do it using what we know of the best practices possible under sort of experimental farm conditions. And there are some things. And this is a cost curve, the width of each wedge tells us how much nitrogen they were able to reduce through that particular operation. And on the Y axis is the cost, how many dollars per kilogram of nitrogen that they removed. So there are some things that are pretty cheap, but they didn't do much. So they improved drainage management a little bit, reduced fertilizer on the corn, soybean rotation, constructing wetlands that intercepts some of the nitrogen and converts it to other forms so it doesn't go into the water bodies into the creek. Another big reduction, reducing nitrogen in continuous corn. But then when you get some of these other possibilities, like winter rye cover crop, it's much more expensive, but it's very effective because over the winter, this. This cover crop is taking up nitrogen out of the soil that was left over from last year, and it's sort of storing it in the plants. And then when that gets turned over in the spring, it becomes available for the next crop. And so it isn't lost from the system through that long fallow period. But it's expensive because it requires the farmer to go out there and till another crop for which there really isn't a market right now in the state of Maryland, the state is subsidizing farmers to plant winter cover crops. Now, why would this Taxpayers of Maryland do that? Because there is both federal and state law saying that they view the quality of the Chesapeake Bay water to be important and to meet the goals of improving water quality in the Chesapeake Bay, both for recreational purposes and shellfish purposes, the states around there have to have plans to reduce nitrogen and phosphorus losses into the river systems that feed into the Chesapeake. And so taxpayers are subsidizing this, and farmers are doing it because they can make money off of it. This other example of no fall application, that's extremely expensive. It doesn't make much sense to most of us that you would put fertilizer out there in the fall and let it sit there all winter long. And then as it warms up in the spring and we get rains in the spring, we'll wash it all away before the crop starts growing. But it's much easier to work in the field fall because it's drier. In the spring it's wet. You've got frozen soils that don't drain very well, and all the melting of the snow and so forth. And so it's very difficult to work. Sometimes you have to apply the fertilizer through aerial applications. And so these are some of the challenges we have of trying to figure out the ways that we can do this more efficiently and cost effectively. One can also think about landscape design, where in the landscape we put cities and industrial processes and grazing land and so forth, and can we intercept the nutrients that are leaving either as the sewage or leaching off of the grazing lands in various ways. We have here at the Woods Hole Research center, one of these denitrifying septic tanks. So by the way, if you'd like to make a contribution before you leave, we'd be happy to reduce your nitrogen for you as it leaves our system and goes into this denitrification septic tank before it goes into the groundwater and goes out to Oyster Bay or Oyster Pond. There are some people at MBL that have been working on these bioreactors, which are basically trenches filled with wood chips that intercept some of the groundwater flow and absorb that nitrogen and reduce it. Buffer strips along the river riparian zone, buffer strips and wetlands can help do that as well. This also came out of a conference that we held that we sponsored. Another conference that's coming up this summer is which we're partnering with the Soil Science Society of America and we're partnering with a couple of fertilizer institutes. These are society organizations formed by fertilizer companies, but these are institutes that are recognizing that they have to address this issue. They have to have science that helps their member associations, their member corporations recognize the issue and how to address the issue. And in some cases they can actually make more profit from it. One of the techniques is something that's called a nitrification inhibitor. It prevents the nitrogen fertilizer from being transformed from one form to another, so it's less likely to be lost. So that's another product that they can sell. And the idea of this particular conference is not to just talk about technical issues, but what are the economic and social impediments? What are the incentives that the farmers are responding to? We're going to have people from the Netherlands come where it's pretty much command and control. The government tells the farmer what they have to do. And then in the US system, we have much more of this free market system, libertarian type system, where so far compliance to reducing nitrogen emissions from farms has been entirely voluntary. What is it that the farmers would respond to in either situation and what can possibly work? We can bring this to home here in Falmouth, looking at East Falmouth, at Green Pond, Horn Pond, each one of these houses has a septic tank. And after all, that is sort of the final repository, right, of agriculture and some, I think it's only 5% or so of the Cape that is sewered. Now. We're facing, of course as taxpayers, huge amounts of money to have to sewer these areas. But the low hanging fruit before even talking about investing the money in sewers is to get people to use the fertilizer on their lawns a little more judiciously. So there is a town bylaw that was passed, but it's being challenged by the local fertilizer and landscaping industry that it is more restrictive than the state law and that the town should not be allowed to pass a more restrictive law than the state law. So. So even this low hanging fruit of trying to reduce runoff of fertilizers into the ponds, which would be less expensive than sewering, although we're going to need something like sewering or some other form of controlling nitrogen as well. But even that is locally reaching some pushback. But ultimately these decisions aren't simply decisions about what's going to happen with development in Africa or what's going to happen on the farm in Iowa. They are also decisions that you and I make every single day in terms of what we eat. This is a chart showing greenhouse gas emissions for different kinds of foods. There's a little bit that's attributed to transportation and so eating locally grown food will help reduce that to some extent. There's a little bit in wholesale and retail, but the vast majority, as you can see from the yellow width of the yellow bar, is the production and it's the productions of these different kinds of food. And of course right here on the top is red meat and dairy products are right below it. Now, this is not to say that we would all be well nourished by eating only oils and sweets and condiments. That's not the point I'm trying to make. Although we are going to offer you cookies afterwards. But the point here, nor is the point that I'm trying to convince everybody to become a vegetarian. I think if that was the message that we made here, we probably wouldn't get many of you coming back for subsequent lectures. The point is not that we have to. It's an all or nothing situation. But we can be thinking about portion size and frequency and it turns out that turns out to be good for your health as well to vary your source of proteins and the portion sizes. So ultimately this kind of comes back to the choices that we make, which is the way I started out the talk that sustainable agriculture, yes, it involves what farmers do, yes, it involves public policy, but it also involves the choices that we make which creates the demand that the farmers respond. One last slide, one last data slide. I can't resist. Nitrous oxide is one of those forms that leaks out. I showed you that leaky pipe, remember, nitrous oxide is one of those. It's also the one that is the ozone depleting substance and a greenhouse gas. And just focus on the dotted lines. This is projecting forward concentrations of nitrous oxide in the atmosphere before the Invention of fertilizer, nitrogen fertilizer. It was down to around 278 activity. It's been increasing ever since because we've been producing more and more food and a little bit leaks out it every time you produce food. Here are some different scenarios. This black one is business as usual. Based on fao Food and Agriculture Organization projections of population increases, improved nutrition, improved increased food production. And as we put more nitrogen through the pipe, more and more is going to leak out and nitrous oxide in the atmosphere just keeps going up and up and up with no stop in sight. This is a less meat scenario. If we in the Western world were to go back to the amount of meat we ate per capita in 1970, I suspect most of you in this room were probably alive in 1970. I don't remember us really suffering all that much regarding the amount of meat we ate back then. But that's. If we were to go back to that in the Western world, that could reduce the amount of N2O accumulated in the atmosphere substantially. Or alternatively, if we continue to eat the same way, but we just get the farmers to be a whole lot more efficient, we could have about the same effect. And there's some other sectors that produce nitrous oxide. Our automobile engines, producing nylon, a few other industrial processes, but that only gets you a little tiny bit of a improvement over the agricultural efficiency. You have to do all of the above in order to get this yellow dotted line that finally levels out, stabilizes in the atmosphere so there's no silver bullet. It's all of the above that we have to do for changing our dietary habits. Improving agricultural efficiency, improving efficiencies in other sectors to get to the point where we actually can stabilize this important greenhouse gas and ozone depleting substance. So the take home message is we have to integrate sustainable agriculture and food security into global and national policies. We need to invest in smart intensification of agriculture. That means more inputs of knowledge, materials and labor. We need to reduce food wastage from the farm to the dinner table. And we need to consider change in dietary habits. Now is that feasible? Well, talk about 1970 again. 1970, at the end of the lecture, we would all go off there and have our cookies and light up cigarettes. So is it possible that by 2050 we will no longer be supersizing the amount of meat that we serve? I don't know. The argument about cigarettes may be more compelling, this may be a more difficult sell. But I just want to point out that human habits do change. And because it is a difficult problem doesn't mean that it is an insurmountable one. So thank you all for your attention, and I'll take some questions, and then we can all have sweets and sugar and condiments to enjoy the rest of the evening. Thank you much.