Tonight, I want to have a conversation about this incredible global issue that's at the intersection of land use, food and environment, something we can all relate to, and what I've been calling the other inconvenient truth.
But first, I want to take you on a little journey. Let's first visit our planet, but at night, and from space. This is what our planet looks like from outer space at nighttime, if you were to take a satellite and travel around the planet. And the thing you would notice first, of course, is how dominant the human presence on our planet is. We see cities, we see oil fields, you can even make out fishing fleets in the sea, that we are dominating much of our planet, and mostly through the use of energy that we see here at night. But let's go back and drop it a little deeper and look during the daytime. What we see during the day is our landscapes.
This is part of the Amazon Basin, a place called Rondônia in the south-center part of the Brazilian Amazon. If you look really carefully in the upper right-hand corner, you're going to see a thin white line, which is a road that was built in the 1970s. If we come back to the same place in 2001, what we're going to find is that these roads spurt off more roads, and more roads after that, at the end of which is a small clearing in the rainforest where there are going to be a few cows. These cows are used for beef. We're going to eat these cows. And these cows are eaten basically in South America, in Brazil and Argentina. They're not being shipped up here. But this kind of fishbone pattern of deforestation is something we notice a lot of around the tropics, especially in this part of the world.
因此我們常被問到的問題是：世上有多少土地被用於生產糧食？這些地方位於何處？未來將發生何種改變？這代表什麼意義？好，我們的團隊觀察全球情況，利用人造衛星蒐集的資訊和地表資料追蹤全球農地規模，這是我們的發現，令人震驚不已。這張地圖顯示農業分布於地表的情形。綠色區域是種植作物的地方，例如小麥、黃豆、玉米或稻米等，相當於1600萬平方公里土地。如果將這些土地集中在同一處，大約相當於南美洲面積。第二片以咖啡色表示的區域是牧地或放牧區，動物生活於此，這片區域大約3000萬平方公里，相當於非洲面積。十分廣大的土地，也是最肥沃的土地。如你們所見，其餘部份為撒哈拉沙漠、西伯利亞或雨林深處，我們已使用了相當於整個地球的土地。如果仔細觀察，將發現大約 40% 的地表貢獻於農業，比令我們怨聲載道的居住地大60倍，包括郊區和大多數人類居住的城市。目前世上有半數人口居住於城市，但生產糧食的土地比人類居住地大60倍，這是十分驚人的事實，令觀察到這一點的我們震驚不已。
If we go a little bit further south in our little tour of the world, we can go to the Bolivian edge of the Amazon, here also in 1975, and if you look really carefully, there's a thin white line through that kind of seam, and there's a lone farmer out there in the middle of the primeval jungle. Let's come back again a few years later, here in 2003, and we'll see that that landscape actually looks a lot more like Iowa than it does like a rainforest. In fact, what you're seeing here are soybean fields. These soybeans are being shipped to Europe and to China as animal feed, especially after the mad cow disease scare about a decade ago, where we don't want to feed animals animal protein anymore, because that can transmit disease. Instead, we want to feed them more vegetable proteins. So soybeans have really exploded, showing how trade and globalization are really responsible for the connections to rainforests and the Amazon -- an incredibly strange and interconnected world that we have today.
Well, again and again, what we find as we look around the world in our little tour of the world is that landscape after landscape after landscape have been cleared and altered for growing food and other crops.
So one of the questions we've been asking is, how much of the world is used to grow food, and where is it exactly, and how can we change that into the future, and what does it mean? Well, our team has been looking at this on a global scale, using satellite data and ground-based data kind of to track farming on a global scale. And this is what we found, and it's startling. This map shows the presence of agriculture on planet Earth. The green areas are the areas we use to grow crops, like wheat or soybeans or corn or rice or whatever. That's 16 million square kilometers' worth of land. If you put it all together in one place, it'd be the size of South America. The second area, in brown, is the world's pastures and rangelands, where our animals live. That area's about 30 million square kilometers, or about an Africa's worth of land, a huge amount of land, and it's the best land, of course, is what you see. And what's left is, like, the middle of the Sahara Desert, or Siberia, or the middle of a rain forest. We're using a planet's worth of land already. If we look at this carefully, we find it's about 40 percent of the Earth's land surface is devoted to agriculture, and it's 60 times larger than all the areas we complain about, our suburban sprawl and our cities where we mostly live. Half of humanity lives in cities today, but a 60-times-larger area is used to grow food. So this is an amazing kind of result, and it really shocked us when we looked at that.
So we're using an enormous amount of land for agriculture, but also we're using a lot of water. This is a photograph flying into Arizona, and when you look at it, you're like, "What are they growing here?" It turns out they're growing lettuce in the middle of the desert using water sprayed on top. Now, the irony is, it's probably sold in our supermarket shelves in the Twin Cities. But what's really interesting is, this water's got to come from some place, and it comes from here, the Colorado River in North America. Well, the Colorado on a typical day in the 1950s, this is just, you know, not a flood, not a drought, kind of an average day, it looks something like this. But if we come back today, during a normal condition to the exact same location, this is what's left. The difference is mainly irrigating the desert for food, or maybe golf courses in Scottsdale, you take your pick. Well, this is a lot of water, and again, we're mining water and using it to grow food, and today, if you travel down further down the Colorado, it dries up completely and no longer flows into the ocean. We've literally consumed an entire river in North America for irrigation.
Well, that's not even the worst example in the world. This probably is: the Aral Sea. Now, a lot you will remember this from your geography classes. This is in the former Soviet Union in between Kazakhstan and Uzbekistan, one of the great inland seas of the world. But there's kind of a paradox here, because it looks like it's surrounded by desert. Why is this sea here? The reason it's here is because, on the right-hand side, you see two little rivers kind of coming down through the sand, feeding this basin with water. Those rivers are draining snowmelt from mountains far to the east, where snow melts, it travels down the river through the desert, and forms the great Aral Sea. Well, in the 1950s, the Soviets decided to divert that water to irrigate the desert to grow cotton, believe it or not, in Kazakhstan, to sell cotton to the international markets to bring foreign currency into the Soviet Union. They really needed the money. Well, you can imagine what happens. You turn off the water supply to the Aral Sea, what's going to happen? Here it is in 1973, 1986, 1999, 2004, and about 11 months ago. It's pretty extraordinary. Now a lot of us in the audience here live in the Midwest. Imagine that was Lake Superior. Imagine that was Lake Huron. It's an extraordinary change.
This is not only a change in water and where the shoreline is, this is a change in the fundamentals of the environment of this region. Let's start with this. The Soviet Union didn't really have a Sierra Club. Let's put it that way. So what you find in the bottom of the Aral Sea ain't pretty. There's a lot of toxic waste, a lot of things that were dumped there that are now becoming airborne. One of those small islands that was remote and impossible to get to was a site of Soviet biological weapons testing. You can walk there today. Weather patterns have changed. Nineteen of the unique 20 fish species found only in the Aral Sea are now wiped off the face of the Earth. This is an environmental disaster writ large.
But let's bring it home. This is a picture that Al Gore gave me a few years ago that he took when he was in the Soviet Union a long, long time ago, showing the fishing fleets of the Aral Sea. You see the canal they dug? They were so desperate to try to, kind of, float the boats into the remaining pools of water, but they finally had to give up because the piers and the moorings simply couldn't keep up with the retreating shoreline. I don't know about you, but I'm terrified that future archaeologists will dig this up and write stories about our time in history, and wonder, "What were you thinking?" Well, that's the future we have to look forward to.
我們已使用了地球上現有的 50% 淡水，光是農業部分就佔用了70%，因此我們在農業上消耗許多水源和土地，我們也在農業上消耗許多大氣。當我們談到大氣時，通常會聯想到氣候變遷和溫室氣體，大多與能源有關，但事實上農業亦是溫室氣體最大來源之一－如果考量焚燒熱帶雨林所產生的二氧化碳，或牛群和稻米所產生的甲烷，或大量肥料所產生的一氧化二氮。事實上，在人類活動當中，排放至大氣層的溫室氣體 30% 來自農業，遠大於所有交通工具、所有電力設施及所有製造業產生的排放量。這是所有人類活動中最大的單一溫室氣體來源，但我們很少提及這一點。
因此，我們目前面臨的是農業主宰地球這個驚人事實，無論是佔用地表 40% 的土地、消耗 70% 的水源、產生 30% 的溫室氣體排放量。光是肥料的使用，就使得逸散到全球環境中的氮、磷量倍增，導致河川、湖泊，甚至海洋的水質產生嚴重問題，這也是導致生物多樣性喪失的最大因素。因此，毫無疑問地，農業是冰河期結束後影響地球環境的最大力量，毫無疑問。它的重要性和氣候變遷不相上下，兩種危機同時發生。
We already use about 50 percent of the Earth's fresh water that's sustainable, and agriculture alone is 70 percent of that. So we use a lot of water, a lot of land for agriculture. We also use a lot of the atmosphere for agriculture. Usually when we think about the atmosphere, we think about climate change and greenhouse gases, and mostly around energy, but it turns out agriculture is one of the biggest emitters of greenhouse gases too. If you look at carbon dioxide from burning tropical rainforest, or methane coming from cows and rice, or nitrous oxide from too many fertilizers, it turns out agriculture is 30 percent of the greenhouse gases going into the atmosphere from human activity. That's more than all our transportation. It's more than all our electricity. It's more than all other manufacturing, in fact. It's the single largest emitter of greenhouse gases of any human activity in the world. And yet, we don't talk about it very much.
So we have this incredible presence today of agriculture dominating our planet, whether it's 40 percent of our land surface, 70 percent of the water we use, 30 percent of our greenhouse gas emissions. We've doubled the flows of nitrogen and phosphorus around the world simply by using fertilizers, causing huge problems of water quality from rivers, lakes, and even oceans, and it's also the single biggest driver of biodiversity loss. So without a doubt, agriculture is the single most powerful force unleashed on this planet since the end of the ice age. No question. And it rivals climate change in importance. And they're both happening at the same time.
But what's really important here to remember is that it's not all bad. It's not that agriculture's a bad thing. In fact, we completely depend on it. It's not optional. It's not a luxury. It's an absolute necessity. We have to provide food and feed and, yeah, fiber and even biofuels to something like seven billion people in the world today, and if anything, we're going to have the demands on agriculture increase into the future. It's not going to go away. It's going to get a lot bigger, mainly because of growing population. We're seven billion people today heading towards at least nine, probably nine and a half before we're done. More importantly, changing diets. As the world becomes wealthier as well as more populous, we're seeing increases in dietary consumption of meat, which take a lot more resources than a vegetarian diet does. So more people, eating more stuff, and richer stuff, and of course having an energy crisis at the same time, where we have to replace oil with other energy sources that will ultimately have to include some kinds of biofuels and bio-energy sources. So you put these together. It's really hard to see how we're going to get to the rest of the century without at least doubling global agricultural production.
此外，我們或許希望農業碳足跡不再攀升、以更佳方式利用土地。這張圖是我們試著標出某些可在不損害環境的前提下提高農產量的地區。綠色部分代表玉米產區，顯示以玉米來說目前產量已相當高的地區，或許是以氣候和土質來說，目前世上產量最高的地區。但咖啡色和黃色部份是僅可獲得 20% 或 30% 產量的地區，你看見大部份位於非洲，甚至拉丁美洲。但令人感興趣的是東歐，它曾經是蘇聯與東歐共產國家所在地，農業發展仍十分落後。現在，這片區域需要養份和水源，需藉由有機或傳統耕作方式，或兩者混合來供應這一切。植物需要水和養份，但我們能做到這一點，我們有成功的機會。
Well, how are we going to do this? How are going to double global ag production around the world?
Well, we could try to farm more land. This is an analysis we've done, where on the left is where the crops are today, on the right is where they could be based on soils and climate, assuming climate change doesn't disrupt too much of this, which is not a good assumption. We could farm more land, but the problem is the remaining lands are in sensitive areas. They have a lot of biodiversity, a lot of carbon, things we want to protect. So we could grow more food by expanding farmland, but we'd better not, because it's ecologically a very, very dangerous thing to do.
Instead, we maybe want to freeze the footprint of agriculture and farm the lands we have better. This is work that we're doing to try to highlight places in the world where we could improve yields without harming the environment. The green areas here show where corn yields, just showing corn as an example, are already really high, probably the maximum you could find on Earth today for that climate and soil, but the brown areas and yellow areas are places where we're only getting maybe 20 or 30 percent of the yield you should be able to get. You see a lot of this in Africa, even Latin America, but interestingly, Eastern Europe, where Soviet Union and Eastern Bloc countries used to be, is still a mess agriculturally. Now, this would require nutrients and water. It's going to either be organic or conventional or some mix of the two to deliver that. Plants need water and nutrients. But we can do this, and there are opportunities to make this work.
But we have to do it in a way that is sensitive to meeting the food security needs of the future and the environmental security needs of the future. We have to figure out how to make this tradeoff between growing food and having a healthy environment work better.
Right now, it's kind of an all-or-nothing proposition. We can grow food in the background -- that's a soybean field — and in this flower diagram, it shows we grow a lot of food, but we don't have a lot clean water, we're not storing a lot of carbon, we don't have a lot of biodiversity. In the foreground, we have this prairie that's wonderful from the environmental side, but you can't eat anything. What's there to eat? We need to figure out how to bring both of those together into a new kind of agriculture that brings them all together.
Now, when I talk about this, people often tell me, "Well, isn't blank the answer?" -- organic food, local food, GMOs, new trade subsidies, new farm bills -- and yeah, we have a lot of good ideas here, but not any one of these is a silver bullet. In fact, what I think they are is more like silver buckshot. And I love silver buckshot. You put it together and you've got something really powerful, but we need to put them together.
So what we have to do, I think, is invent a new kind of agriculture that blends the best ideas of commercial agriculture and the green revolution with the best ideas of organic farming and local food and the best ideas of environmental conservation, not to have them fighting each other but to have them collaborating together to form a new kind of agriculture, something I call "terraculture," or farming for a whole planet.
Now, having this conversation has been really hard, and we've been trying very hard to bring these key points to people to reduce the controversy, to increase the collaboration. I want to show you a short video that does kind of show our efforts right now to bring these sides together into a single conversation. So let me show you that. (Music) ("Institute on the Environment, University of Minnesota: Driven to Discover") (Music) ("The world population is growing by 75 million people each year. That's almost the size of Germany. Today, we're nearing 7 billion people. At this rate, we'll reach 9 billion people by 2040. And we all need food. But how? How do we feed a growing world without destroying the planet? We already know climate change is a big problem. But it's not the only problem. We need to face 'the other inconvenient truth.' A global crisis in agriculture. Population growth + meat consumption + dairy consumption + energy costs + bioenergy production = stress on natural resources. More than 40% of Earth's land has been cleared for agriculture. Global croplands cover 16 million km². That's almost the size of South America. Global pastures cover 30 million km². That's the size of Africa. Agriculture uses 60 times more land than urban and suburban areas combined. Irrigation is the biggest use of water on the planet. We use 2,800 cubic kilometers of water on crops every year. That's enough to fill 7,305 Empire State Buildings every day. Today, many large rivers have reduced flows. Some dry up altogether. Look at the Aral Sea, now turned to desert. Or the Colorado River, which no longer flows to the ocean. Fertilizers have more than doubled the phosphorus and nitrogen in the environment. The consequence? Widespread water pollution and massive degradation of lakes and rivers. Surprisingly, agriculture is the biggest contributor to climate change. It generates 30% of greenhouse gas emissions. That's more than the emissions from all electricity and industry, or from all the world's planes, trains and automobiles. Most agricultural emissions come from tropical deforestation, methane from animals and rice fields, and nitrous oxide from over-fertilizing. There is nothing we do that transforms the world more than agriculture. And there's nothing we do that is more crucial to our survival. Here's the dilemma... As the world grows by several billion more people, We'll need to double, maybe even triple, global food production. So where do we go from here? We need a bigger conversation, an international dialogue. We need to invest in real solutions: incentives for farmers, precision agriculture, new crop varieties, drip irrigation, gray water recycling, better tillage practices, smarter diets. We need everyone at the table. Advocates of commercial agriculture, environmental conservation, and organic farming... must work together. There is no single solution. We need collaboration, imagination, determination, because failure is not an option. How do we feed the world without destroying it? Yeah, so we face one of the greatest grand challenges in all of human history today: the need to feed nine billion people and do so sustainably and equitably and justly, at the same time protecting our planet for this and future generations. This is going to be one of the hardest things we ever have done in human history, and we absolutely have to get it right, and we have to get it right on our first and only try. So thanks very much.