Outgrowing the Earth Part 7 – Willis Ceramics

OUTGROWING THE EARTH

THE FOOD SECURITY CHALLENGE IN AN AGE OF FALLING WATER TABLES AND RISING TEMPERATURES

LESTER BROWN

EARTHSCAN 2005

PART VII

Chapter 5: Protecting Cropland

On April 18, 2001, the western United States – from the Arizona border north to Canada – was blanketed with dust. The dirt came from a huge dust storm that originated in northwestern China and Mongolia on April 5. Measuring 1,800 kilometers across when it left China, the storm carried up to 100 million tons of topsoil, a vital resource that would take centuries to replace through natural processes.

Almost exactly one year later, on April 12, 2002, South Korea was engulfed by a huge dust storm from China that left people in Seoul literally gasping for breath. Schools were closed, airline flights were cancelled, and clinics were overrun with patients having difficulty breathing. Retail sales fell. Koreans have come to dread the arrival of what they now call “the fifth season,” the dust storms of late winter and early spring.

These two dust storms, among some 20 or more major dust storms in China during 2001 and 2002, are one of the externally visible indicators of the ecological catastrophe unfolding in northern and western China. Overgrazing and overplowing are converting productive land to desert on an unprecedented scale. Other dust storms are occurring in Africa, mostly in the southern Sahara and the Sahelian zone. Scientists estimate that Chad alone may be exporting 1.3 billion tons of topsoil each year to the Atlantic Ocean, the Caribbean islands, and even Florida in the United States. Wind erosion of soil and the resulting desert creation and expansion are shrinking the cropland base in scores of countries.

Another powerful pressure on cropland is the automobile. Worldwide, close to 400,000 hectares (1 million acres) of land, much of it cropland, are paved each year for roads, highways, and parking lots. In densely populated, low-income developing countries, the car is competing with farmers for scarce arable land.

The addition of more than 70 million people each year requires land for living and working – driving the continuous construction of houses, apartment buildings, factories, and office buildings. Worldwide, for every 1 million people added, an estimated 40,000 hectares of land are needed for basic living space.

These threats to the world’s cropland, whether advancing deserts, expanding automobile fleets, or housing developments, are gaining momentum, challenging some of the basic premises on which current population, transportation, and land use policies rest.

Losing soil fertility

Soil erosion is not new. It is as old as the earth itself. But with the advent of agriculture, the acceleration of soil erosion on mismanaged land is increased to the point where soil loss often exceeded new soil formation. Once this threshold is crossed, the inherent fertility of the land begins to fall.

Each year the world’s farmers are challenged to feed another 70 million or more people but with less topsoil than the year before.

In farming, erosion comes from plowing land that is steeply sloping or too dry to support adequate soil protection with ground cover. Steeply sloping land that is not protected by terraces, by perennial crops, or some other way loses soil when it rains heavily. Thus the land hunger that drives farmers up mountainsides fuels erosion. Land that is excessively dry, usually receiving below 25 centimeters (10 inches) of rain a year, is highly vulnerable to wind erosion once vegetation, typically grass, is cleared for cropping or by overgrazing. Under cultivation, this soil often begins to blow away.

In the United States, wind erosion is common in the semiarid Great Plains, where the country’s wheat production is concentrated. In the US Corn Belt, where most of the country’s corn and soybeans are grown, the principal erosion threat is from water. This is particularly true in the states with rolling land and plentiful rainfall, such as Iowa and Missouri.

Land degradation from both water and wind erosion in the world’s vulnerable drylands is extensive, affecting some 900 million hectares (see table 5-1), an area substantially larger than the world’s grainlands (some 670 million hectares).
Two thirds of this damaged land is in Africa and Asia, including the Middle East. These also are the world’s two most populous regions.
And they are where fully two thirds of the 3 billion people expected to be added to world population by 2050 will live.
If more people translate into more livestock, as historically has been the case, the damage will spread to still more land.

The enormous 20th century expansion in world food production pushed agriculture onto highly vulnerable land in many countries. The overplowing of the US Great Plains during the late 19^th and early 20^th century, for example, led to the 1930s Dust Bowl. This was a tragic era in US history – one that forced hundreds of thousands of farm families to leave the Great Plains. Many migrated to California in search of a new life, a movement immortalized in John Steinbeck’s The Grapes of Wrath.

Three decades later, history repeated itself in the Soviet Union. The Virgin Lands Project, a huge effort to convert grassland into grainland between 1954 and 1960, led to the plowing of an area for wheat that exceeded the wheatland in Canada and Australia combined. Initially this resulted in an impressive expansion in Soviet grain production, but the success was short-lived as a dust bowl developed there too.

Kazakhstan, at the center of the Virgin Lands Project, saw its grainland area peak and begin to decline around 1980. After reaching a historical high of just over 25 million hectares, it shrank to barely half that size – 13 million hectares. Even on the remaining land, however, the average wheat yield is only 1.1 tons per hectare, a far cry from the nearly 7 tons per hectare that farmers get in France, Western Europe’s leading wheat producer and exporter. This precipitous drop in Kazakhstan’s grain harvest illustrates the price that other countries will have to pay for overplowing and overgrazing.

In the closing decades of the 20th century, yet another dust bowl – perhaps the biggest of all – began developing in China. As described in Chapter 8, it is the result of overgrazing, overplowing, over cutting of trees, and overpumping of aquifers, all of which make the land in northern and western China vulnerable to erosion.

Africa, too, is suffering from heavy losses of topsoil as a result of wind erosion. Andrew Goudie, Professor of Geography at Oxford University, reports that dust storms originating over the Sahara – once so rare – are now commonplace. He estimates they have increased tenfold during the last half-century. Among the countries most affected by topsoil loss via dust storms are Niger, Chad, northern Nigeria, and Burkino Faso. In Mauritania, in Africa’s far west, the number of dust storms jumped from 2 a year in the early 1960s to 80 a year today.

The Bodélé Depression in Chad is the source of an estimated 1.3 billion tons of dust a year, up tenfold from 1947, when measurements began. Dust storms leaving Africa travel westward across the Atlantic, depositing so much dust in the Caribbean that they damage coral reefs there.

The 2 – 3 billion tons of fine soil particles that leave Africa each year in dust storms are slowly draining the continent of its fertility and, hence, its biological productivity.
Dust storms and sand storms are a regular feature of life in the Middle East as well.
The bottom line is that the accelerating loss of topsoil from wind and water erosion is slowly but surely reducing the earth’s inherent biological productivity. Unless governments, farmers, and herders can mobilize to reverse this trend, feeding 70 million more people each year will become progressively more difficult.

Advancing deserts

Roughly one tenth of the earth’s surface is used to produce crops. Two tenths is grassland of varying degrees of productivity. Another two tenths is forest. The remaining half is either desert, mountains, or covered with ice. The area in desert is expanding, largely at the expense of grassland and cropland. Deserts are advancing in Africa both north and south of the Sahara and throughout the Middle East, the Central Asian republics, and western and northern China. (See Table 5-2.) (The effect of desertification on China’s food production is discussed in more detail in Chapter 8.)

Nigeria, Africa’s most populous country, is losing 351,000 hectares of rangeland and cropland to desertification each year.
The government of Nigeria considers the loss of productive land to desert to be far and away its leading environmental problem.
Conditions will only get worse if Nigeria continues on its current population trajectory toward 258 million people by 2050.

In the vast swath of Africa between the Sahara Desert and the forested regions to the south lies the Sahel. In countries from Senegal and Mauritania in the west to Sudan, Ethiopia, and Somalia in the east, human and livestock pressures are converting more and more land into desert.

A similar situation exists along the Sahara’s northern edge, the tier of largely semiarid countries across the top of Africa.
Some of the most severe desertification found anywhere is in China, where 360,000 hectares of land become desert each year.
In regions of desert expansion, sandstorms are common, often forcing the abandonment of villages.
Special crews periodically follow the phone lines across the countryside looking for poles that may be about to be inundated with drifting sand.

Converting cropland to other uses

In addition to losing cropland to severe soil erosion and desert expansion, the world is also losing cropland to various nonfarm uses, including residential construction, the paving of roads and parking lots, and airports, as well as to recreational uses, such as tennis courts and golf courses.
If for every million people added to the world’s population, 40,000 hectares of land are needed for nonfarm uses, adding more than 70 million people each year claims nearly 3 million hectares, part of which is agricultural land.
The cropland share of land converted to nonfarm uses varies widely both within and among countries, but since cities are typically located on the most fertile land, it is often high – sometimes 100%.
China is currently working to create 100 million jobs in the manufacturing sector. With the average factory in China employing 100 workers, China needs to build 1 million factories – many of which will be sited on former cropland.
If we assume each dwelling houses on average five people, then adding 70 million people to world population each year means building 14 million houses or apartments annually.
The world automobile fleet is expanding by roughly 9 million per year. Each new million cars require the paving of roughly 20,000 hectares of land, which translates into 50,000 tons of grain, enough to feed 250,000 people.
As the new century gets under way, the competition between cars and crops is heating up.
There is not enough land in China, India, and other densely populated countries like Indonesia, Bangladesh, Pakistan, Iran, Egypt, and Mexico to support automobile-centered transportation systems and feed people.
The competition between cars and crops for land is becoming a struggle between the rich and the poor – between those who can afford automobiles and those who are struggling to get enough food to survive.

Conserving topsoil

Easily 5% of the world’s cropland is highly erodible and should be converted back to grass or trees before it becomes wasteland.
The first step to halting the decline in inherent land fertility is to pull back from this fast-deteriorating margin.
The key to controlling wind erosion is to keep the land covered with vegetation as much as possible and to slow wind speeds at ground level.
Wind turbines can simultaneously slow wind speeds and provide cheap electricity.
One time-tested method for dealing with water erosion is terracing. On less steeply sloping land, contour strip farming works well.
Conservation tillage includes both no till and minimum tillage. In the United States, the no-till area went from 7 million hectares in 1990 to nearly 24 million hectares in 2003/04.
This practice helps retain water, raises soil carbon content, and reduces the energy needed for crop cultivation.

Saving cropland

Ideally we would build our homes, offices, factories, shopping malls, roads, and parking lots only on land that is unsuitable for farming.
The US sprawl model of development is not only land-intensive, it is also energy-inefficient and aesthetically unappealing.
European governments have carefully zoned their urban development, leading to a much more land-efficient, energy-efficient, aesthetically pleasing approach.
We are indebted to scientists for recognizing early on that the automobile-centered, western industrial development model is not appropriate for densely populated developing countries.
Amsterdam and Copenhagen, where up to 40% of all trips within the city are taken by bicycle, are leading the way.
In a world of 6 billion people, transportation policy and food security are intimately related.

Data for figures and additional information can be found at www.earth-policy.org/Books/Out/index.htm

Chapter 6: Stabilizing Water Tables