by Al Gore
According to ecologist Peter Gleick, we should view efficiency as a giant wellspring that could provide vast new quantities of needed freshwater. Unfortunately, this wellspring, like many of the aquifers now being recklessly depleted, also seems to be out of sight, out of mind. The majority of agricultural irrigation practices are still extremely wasteful. Switching to scientifically precise drip irrigation techniques is cost-effective in most agricultural operations, but many farmers have been slow to make the change. Another benefit of switching to more efficient and precise methods of irrigation is that wasteful and excessive irrigation of crops increases the salinity of soils—because the irrigation water usually contains small amounts of salt that build up with continued use.
The recycling of water is growing in popularity. Some communities already require the use of greywater—used water that is not suitable for drinking but is safe for watering plants. The more controversial recycling proposals take sewage water and remove all of the contaminants, purify it, and put it into drinking water systems. There is still a great deal of consumer resistance to these plans, but some communities have successfully implemented the approach.
In regions where rainfall is becoming more concentrated in large downpours—interrupted by longer periods of drought—many experts are calling for the increased use of cisterns to capture more of the rainfall and store it for drinking water. This once common practice fell out of favor with the extension of underground water lines from reservoirs. I remember the cisterns we used to have on our family farm when I was a boy. We stopped using them when we got “city water.”
THE STATE OF the world’s topsoil is threatened by the same willfully blind overexploitation that has caused shortages of freshwater. In the world’s prevailing system of accounting, neither water nor topsoil are assigned any value. Therefore, wasteful and destructive practices that diminish the supplies of both are invisible in the world’s economic calculations. Yet topsoil, along with water, is the basis for virtually all human life on Earth. More than 99.7 percent of food consumed by human beings comes from cropland, more specifically from the six to eight inches of topsoil that cover roughly 10 percent of the Earth’s surface.
On a global basis, we are effectively strip-mining this crucial resource in an unsustainable pattern, by recklessly plowing erodible soils, overgrazing grasslands, taking arable land for buildings and roads to accommodate urban and suburban sprawl, tolerating reckless deforestation, and failing to use proven land management techniques that replenish soil carbon and nitrogen.
At present, every kilogram of corn produced in the American Midwest results in the loss of more than a kilogram of topsoil. In some states, such as Iowa, the ratio is even higher: 1.5 kilograms of topsoil lost for each kilogram of grain. These rates of soil loss are not sustainable. They deplete soil carbon, thus damaging the productivity of the soil over time, and accelerate the emission of carbon dioxide into the atmosphere.
We already know how to slow and reverse soil erosion, but global leadership would be required to mobilize the community of nations in the same way that FDR mobilized the United States in the 1930s. Organic agriculture with low-till and no-till practices can sharply reduce soil loss while simultaneously increasing the fertility of the topsoil. Crop rotation, a technique that used to be widespread before industrial agriculture took over, can replenish soil carbon and nitrogen.
Another once common technique that has since been abandoned in large areas of the world is the recycling of animal manure as fertilizer for crops. Factory farming—the clustering of thousands of head of livestock in crowded feedlots and feeding them corn—has turned this natural fertilizer into highly acidic toxic waste that is harmful to crops and thus becomes an expensive liability instead of a valued asset.
A major study in 2012 by leading researchers at the University of Minnesota, Iowa State University, and the Agricultural Research Service of the U.S. Department of Agriculture showed that the use of nontoxic manure as fertilizer and a three-year crop rotation designed to replenish soil fertility reduced the need for herbicides and nitrogen fertilizer by almost 90 percent, without reducing profits. One of the researchers, Professor Matt Liebman of Iowa State, said that one of the reasons farmers do not use the approach recommended in the study is that “there’s no cost assigned to environmental externalities.”
For the last century, modern agriculture has been based on heavy use of synthetic nitrogen fertilizer—90 percent of the cost of which is from natural gas, from which virtually all of the nitrogen is derived. However, agricultural productivity growth has been slowing even as fertilizer use per acre has been increasing dramatically. Moreover, the heavy use of nitrogen in agriculture has caused significant water pollution problems around the world as it runs off farmland with the rain and feeds uncontrolled massive algae blooms in coastal regions of the ocean—and dead zones, areas devoid of life, which are growing in several ocean regions, including the part of the Gulf of Mexico into which the Mississippi River drains. In China the use of synthetic nitrogen fertilizer has increased by 40 percent in the last two decades even though grain production has remained relatively stable; it is this nitrogen runoff that has produced the recent spectacular algae blooms in Chinese rivers, lakes, and coastal areas.
Additional nitrogen emissions from the combustion of fossil fuels in factories, on farms, and in cars and trucks have created significant air pollution problems, particularly in the U.S., China, Southeast Asia, and parts of Latin America. More efficient and targeted use of nitrogen fertilizers, and tighter restrictions on emissions from factories and vehicles, are needed to address the problem.
While nitrogen supplies are not limited, there is a potentially serious emerging limit to the supply of another crucial component of fertilizer—phosphorus, which is a relatively rare element on the Earth. Even as conventional sources of phosphorus are running out, modern agricultural techniques have tripled the depletion of phosphorus from cropland.
A PHOSPHORUS CARTEL?
The first warning about a phosphorus shortage in a 1938 message to Congress, by President Roosevelt, led to a successful worldwide search for additional reserves—including the discovery of phosphates near Tampa, Florida, where 65 percent of U.S. production now takes place. But while the United States produces 40 percent of the world’s corn and soybeans, it produces only 19 percent of the world’s phosphorus, which, in the long run, is essential for agriculture to continue—and so now the search for new reserves is beginning again.
Forty percent of the world’s current supply of phosphates (the most common form in which phosphorus occurs) is in Morocco, which has been called the “Saudi Arabia of phosphorus.” The next largest reserves are found in China, which imposed a 135 percent tariff on exports during the 2008 food price crisis. Many experts fear that similar hoarding of phosphorus could occur if food prices continue to go up, although other experts are more sanguine about the possibility of finding new sources in unconventional locations, such as the ocean floor.
Phosphorus is essential to all life, including human life. It makes up the backbone of DNA, among other things, and fully one percent of the bodyweight of human beings is made up of phosphorus; in fact, the seven billion people on Earth discard large quantities in urine every day. Some countries are now actively exploring the recycling of urine in order to extend the supplies of phosphorus for fertilizers.
The addition of rhizobium bacteria and mycorrhizal fungi to soils as seeds are planted can improve crop yields and also speed the recovery of soil fertility and enhance the sequestration of soil carbon. The planting of leguminous trees every thirty feet or so as buffer strips and contour hedges can replenish nitrogen in the soil and further protect against erosion. Leaving the majority of crop residue—like corn stover—on the land during and after harvesting the crop can also restore the fertility of the soil while diminishing erosion. The use of biochar (from sustainable sources) in a carefully managed way can also improve yields and soil quality. The reducti
on of meat as a percentage of a healthy diet can relieve pressure on the Earth’s topsoil. And the expansion of small-scale organic gardens in countries with a surplus of arable land could potentially add significant volumes of fresh food to the world supply, as they did in Western countries when Victory Gardens were planted during World War II.
But perhaps the single most effective measure to protect topsoil would be to use carbon credits to provide an additional source of income for farmers who pay careful attention to safeguarding and improving the carbon content and fertility of their soils.
So long as the world ignores the value of topsoil in its constant calculations of growth and productivity, the demands placed on agriculture by the combination of growing population and growing per capita consumption of food will continue putting the future of topsoil at severe risk. At current consumption rates (which are still increasing), we need an additional 15 million hectares each year to keep up with the extra food production needed for the increasing population. Yet we are destroying and losing approximately 10 million hectares (approximately 25 million acres) every year. At present, much of the additional cropland being developed results in deforestation—often in forest areas that have very thin topsoils that are quickly depleted by wind and water after the trees are gone. In addition, the more forestland that is converted to farmland, the more biodiversity is lost.
In some respects, the global topsoil crisis is an echo of what happened in the United States in the first third of the twentieth century when the first mass market tractors—pulling the more efficient plows that had been invented three quarters of a century earlier—broke the sod of erodible grasslands in the Midwest for crops; over the next three decades the vulnerable topsoil was washed and blown away, creating the Dust Bowl of the 1930s. Less well known in the U.S. is the even larger tragedy experienced in Central Asia during the 1950s when the USSR plowed an enormous area of grassland—mostly in Kazakhstan (1954)—and created their own Dust Bowl.
Another epic land-use catastrophe occurred in Central Asia in the 1960s, when the USSR embarked on a shortsighted plan to grow thirsty cotton crops in dryland areas of Uzbekistan and Turkmenistan. So much water was diverted from two rivers—the Amu Darya and the Syr Darya—that the world’s fourth largest inland sea, the Aral Sea, almost completely disappeared. I visited the Aral Sea two decades ago and saw firsthand the tragedy that resulted for the people who used to depend on it.
DUST STORMS AHEAD
My father’s generation was motivated by the U.S. soil erosion crisis to adopt new land management techniques. One of the great accomplishments of FDR’s New Deal was the massive program to reconvert eroded land to grassland and a nationwide effort to fight soil erosion. I still remember my father teaching me when I was a young boy how to stop gullies before they began cutting deep into the soil, and how to recognize the richest soil—it’s black from all the organic carbon in the soil.
Modern-day dust storms are now once again increasing in size and frequency as drylands are being overgrazed and erodible soils are subjected to higher temperatures and stronger winds. “Drylands are on the front line of the climate change challenges for the world,” said Luc Gnacadja, who heads the U.N. Convention to Combat Desertification. The U.N. Environment Programme reports that land degradation in drylands threatens the way of life for an estimated one billion people in 100 countries. Desertification is taking a toll on topsoil and destroying arable cropland—particularly in regions of Africa north and south of the Sahara, throughout the Middle East, in Central Asia, and in large areas of China, where overgrazing, poor cultivation techniques, and urban sprawl are contributing significantly to the phenomenon.
In the U.S., in July of 2011, Phoenix, Arizona, was covered with dust when, in the words of the National Weather Service, “A very large and historic dust storm moved through a large swatch of Arizona.” Although these Southwestern U.S. dust storms, often called haboobs, are not new, Phoenix has had an unusually large number of them in recent years—seven in 2011 alone.
The U.S. Geological Survey and UCLA conducted a study in 2011 that predicted “accelerated rates of dust emission from wind erosion” as a result of climate change in the Southwestern United States. Climate expert Joseph Romm has recommended use of the term “dust-bowlification” as a way of describing what is in store for many regions of desertifying drylands.
Lester Brown, long one of the world’s leading environmental experts, points out that the two most significant desertifying areas now generating dust storms are in north-central China and in the areas of Central Africa that lie on the southern edge of the Sahara Desert. As Brown puts it, “Two huge dust bowls are forming, one across northwest China, western Mongolia, and central Asia; the other in central Africa.”
According to geographer Andrew Goudie at Oxford, dust storms from the Sahara have increased tenfold during the last fifty years. The chairman of the African Union, Jean Ping, says, “The phenomenon of desertification affects 43 percent of productive lands, or 70 percent of economic activity and 40 percent of the continent’s population.” In large areas of Sub-Saharan Africa, soil carbon content is now lower than it was in the United States’ Midwest just prior to the Dust Bowl.
In Nigeria, while human population increased fourfold over the last sixty years, the number of livestock exploded from six million to more than 100 million. Partly as a result, the northern region of Nigeria is being desertified—which is contributing to growing clashes between Muslims moving from the north into non-Muslim areas in southern Nigeria. Growth in the population of both humans and livestock is also driving competition for land in other drying areas of Africa and has led to deadly conflicts between herders and farmers (whose ethnicities and religions are also different), who have fought one another in Sudan, Mali, and elsewhere.
The same livestock population explosion is damaging the overgrazed grasslands surrounding China’s Gobi Desert, where the dust storms are also increasing dramatically. While the United States and China have roughly the same amount of grazing land and roughly the same number of cattle (80–100 million), China has 284 million sheep and goats compared to less than 10 million in the United States. According to the latest statistics available, China is now losing almost 1,400 square miles of arable land to deserts every year.
The U.S. embassy in China has used satellite photos to illustrate the “desert mergers and acquisitions” in north-central China where two deserts in Inner Mongolia and Gansu Province are merging and expanding. In Xinjiang Province in northwestern China, the same thing is happening, as the Taklamakan and Kumtag deserts are also merging and expanding. More than 24,000 villages and their surrounding cropland have had to be at least partially abandoned in these northern and western regions of China. Similar tragedies are unfolding in both Iran and Afghanistan, both of which have already abandoned many villages to the encroaching desert.
While the massive sandstorms in China and Africa are capturing attention today, Lester Brown warns, “A third massive cropland expansion is now taking place in the Brazilian Amazon Basin and in the cerrado, a savannah-like region bordering the basin on its south side.” These soils are highly erodible and the results are predictable: low yields, followed by soil erosion on a massive scale. The knock-on effects also include the further expansion of cattle ranching into the Amazon rainforest, adding even more risk to the integrity of that globally important ecosystem. The Amazon has already suffered from two “hundred-year droughts” in the last seven years. As the deforestation and the wildfires continue in the Amazon, many experts have expressed concern that the Amazon is in danger of being transformed over time from the greatest tropical rainforest on Earth into a massive dryland region.
With the rapidly increasing populations in Africa and the Middle East, and impending food shortages, it is remarkable that the world has paid so little attention to the desertification crisis. According to the U.N. Convention to Combat Desertification’s Luc Gnacadja, the reason desertification has not become a higher p
riority is that 90 percent of the people affected live in developing countries. It is another example of the imbalance of power in the world—and the lack of leadership. Gnacadja added, “The top 20 centimeters of soil is all that stands between us and extinction.”
The loss of arable land is particularly acute in the most populated nation of North Africa. According to the United Nations, Egypt is now losing an incredible 3.5 acres per hour of its fertile agricultural land in the Nile Delta—mainly because of new construction and urban sprawl to accommodate additional shelter for Egypt’s fast growing population.
In addition, rising sea level in the Mediterranean is already pushing saltwater aquifers upward in areas near the coast, resulting in the loss of cropland to salinization. Salinization is also occurring in the rich Ganges Delta, the Mekong Delta, and in other so-called mega-deltas. A one-meter rise in sea level—less than that predicted during this century—would inundate a significant percentage of the most fertile soils in the Nile Delta—from whence 40 percent of Egypt’s food production comes.
The pressure created by the increased use of water-intensive agriculture, population growth, and economic expansion is increasing tensions over the allocation of river water in several regions of the world where the management of rivers and dams affects watersheds shared by multiple countries. The potential for conflict is building in the Nile River watershed, where the largest country dependent on the Nile, Egypt, now benefits from its allocation of the majority of the Nile’s water. But Ethiopia, where 85 percent of the Nile’s headwaters originate but where very little of that water is now consumed, will double its population in the next thirty-seven years—and Sudan, which also depends on the Nile, is expected to increase its population 85 percent during the same period.