Note: The data found below represent a sampling of a much larger collection of data compiled in "Grazing Lands Degradation: A Global Perspective," found on this same website.

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Section [A] ~ ELEMENTS OF NON-SUSTAINABILITY

Grasslands and pasturelands form the largest single component of the Earth's 117 million km² of vegetated lands, and of its roughly 90 million km² of reasonably biologically productive land. Domestic livestock graze on about 56 million km² (07S1). Few grasslands are not grazed. Little of what is grazed is not over-grazed. Virtually any analysis you find that compares croplands, forested lands, grazing lands and irrigated lands will show grazing lands to be the most degraded. The deck is stacked against them. They have poor soils with low organic matter contents, making them easily eroded by water or wind. Being generally semi-arid or arid means that the risk of wind erosion is high. Also the scarcity of arable land in the developing world means that low-grade croplands are replacing the better grazing lands. The results of that we all know too well - recall the Dust Bowl in the US or the "Great Lands" debacle in the former Soviet Union. Also grazing lands are rapidly replacing tropical rainforests in Latin America where tropical soils (with their low organic matter contents) are so poor that the pastures must be abandoned after 5-10 years. Photosynthetic rates on various categories of grasslands are known, as are the amounts of grass and grain needed to produce a pound of meat from grazing livestock. These data indicate that the grazing-livestock carrying capacity of the world's grasslands and pasturelands is roughly half of the actual population. The combination of over-grazing and low soil erosion resistance on semi-arid lands (due to low soil organic matter contents) causes soil loss per unit area from semi-arid grasslands to be significantly higher (roughly twice as high in the US) than from even croplands, even though properly grazed grasslands are intrinsically less erosion-prone. Soil loss, riparian habitat losses, and invasion by non-edible or toxic exotic species are all occurring on a massive scale. Much (often 80+%) of the productivity of semi-arid grasslands is in its riparian habitats. Even in the US, where human pressures on the land are less than the global average, these riparian habitats have been 80-90% destroyed by livestock because, in arid and semiarid habitats, that is where livestock prefer to congregate. Because of over-grazing-caused soil erosion, riparian habitat destruction, and the absence of reserves of non-grazed grasslands, grazing livestock is increasingly being grain-fed in feedlots and concentrated animal feedlot operations (CAFOs). This reduces the overall efficiency of the world's food supply system and puts added pressures on croplands. It also deprives croplands of the organic matter needed to replace losses, maintain fertility, maintain erosion resistance, and counter the degradation caused by increasing rates of inorganic (chemical) fertilizer application.

Livestock ownership currently supports and sustains the livelihoods of an estimated 675 million rural poor (99L2) (03S2) These people (about 10% of the Earth's population) depend on pastures and rangelands for feed for their livestock and thus are dependent on the sustainability of outputs from these land resources.

In Swiss alpine villages, social regulations limiting overgrazing have been maintained for many generations (02M4). There are few, if any, other instances of regulations effectively limiting overgrazing anywhere else in the world.

There is wide agreement that (a) semi-arid and arid grasslands are badly overgrazed virtually everywhere on earth and (b) the result of overgrazing is long-term reduction of grassland productivity (02M4).

(Riparian Habitats) In even worse shape are the riparian habitats within grazed semi-arid and arid rangelands. Riparian habitats, even though they typically occupy only a few percent of the rangeland area, provide a large fraction of the biomass productivity of semi-arid and arid grazing lands. Riparian habitats in grasslands receive a very large fraction of the grazing pressures of livestock. They are not just over-grazed; they are usually obliterated even in developed nations like the US where population pressures upon the land are far less than in developing nations (02M4).

(Forested Grasslands) Forested grasslands occupy roughly 10 million of the 90 million km² of the Earth's reasonably biologically productive lands. Nearly all forested grasslands are grazed, and usually overgrazed. Overgrazing degrades both the grass and the forest and reduces timber-productivity as well as grazing productivity (96B1). Overgrazing increases the ability of woody brush understory to compete with grassy understory. This results in woody brush understory replacing the grassy understory. (Cattle do not normally eat woody brush understory.) This makes forest fires more frequent and far more damaging (96B1). (Trees - and homes - can easily withstand grass fires but not the fires in woody brush understory because the biomass density is so much greater.) Trees in climax forests of forested grasslands tend to be fire-resistant species, but after a fire that destroys the trees and woody brush understory, the new trees that grow in tend to be tree species of low fire-resistance (96B1).

Overgrazing would be expected to be most severe where population pressures upon the land are most severe, i.e. in developing nations. Topsoil loss data tend to bear this out (07S1) (07S2).

Overgrazing has inherent side effects that make matters even worse. These include:

• The competition between grass and woody plants is tilted in favor of woody plants as a result of overgrazing. This is because livestock find woody plants less palatable than grass. This decreases the grazing productivity of the land - often to zero.
• Soil bared by overgrazing becomes prime habitat for invasive species that frequently are not palatable to, or are toxic to, livestock. Also these invasive species often out-compete native grasses and spread rapidly over the range. This too reduces the grazing productivity of the land, often to an extreme degree.
• In forested grasslands, overgrazing tilts the competition between grass and woody shrubs in favor of woody shrubs. As a result, fires that would do little or no damage to a forest with a grass floor become intense enough to destroy the trees as well as the woody understory.
• Soils in semi-arid and arid areas are typically very low in organic matter. As a result these soils are far more erosion-prone that soils in moisture climates. Overgrazing exposes these soils to winds and wind erosion. The result is often wind-blown sand dunes (deserts) that spread over more fertile areas and over urban areas that must then be abandoned.
• The trampling of livestock hooves destroys microbiotic (cryptogamic) soil crusts that are delicate symbioses of cyanobacteria, lichens and mosses. These crusts perform the major share of nitrogen fixation in desert ecosystems (78R1). The availability of nitrogen in the soil is a primary limiting factor on biomass production in deserts. These crusts also stabilize arid soils against erosion.
• Huge areas in Latin America are being converted from food/ wood production for local, high-labor-input-low-capital-input markets to cattle ranching for export to the global marketplace. This is true even though grazing lands in typically low-fertility tropical soils become unproductive in 7-8 years and must be fallowed for 20 or so years to regain fertility). About 2/3 of Central America's arable land is now (1991) devoted to cattle production (91J1). Results have been negative for local residents, as evidenced by decreases even in local meat consumption (83N1). Tropical rainforests used for shifting cultivation, acre-for-acre, provide hundreds of times more jobs for developing world inhabitants than grazing lands. Also, meat from tropical grazing lands is typically exported to developed-world countries, whereas tropical rainforests typically provide food/ wood for local inhabitants. The net result is less food for developing-world inhabitants, and more food for those in the developed-world.
• Because rates of soil erosion from grazed grasslands tend to be so much greater than even from croplands, dam backwaters in semi-arid and arid regions fill up with silt much faster. (For global data on siltation of dam backwaters see Section [4-G-c] of Ref. [07S2].) In semi-arid and arid regions, dam backwaters are usually vital components of irrigation systems and water supply systems for urban areas.
• Overgrazing by cattle makes grass blades very short. This results in replacement of cattle by sheep and goats that are capable of reducing the length of grass blades even further. This harms the root systems of grasses, reducing the biomass productivity of grasslands.

Below is a summary of some of the main sustainability problems facing the world's grazing lands.

• Nearly universal overgrazing of grasslands, resulting in reduced biomass productivity,
• High rates of reservoir sedimentation as a result of overgrazing;
• Destruction (via overgrazing) of cryptogamic crusts that normally provide a major share of soil nitrogen in arid grasslands;
• Creation (via overgrazing) of wind-blown soils that promote desertification, expansion and migration of deserts in semi-arid and arid climates, and abandonment of urban areas, croplands, grazing lands and forests;
• Creation (via overgrazing) of woody biomass in forested grasslands, creating forest fires that destroy both trees and ground cover instead of just grass, as would normally be the case;
• Replacement (via overgrazing) of grasses by inedible woody ground cover (brush);
• Replacement (via overgrazing) of nutritious native grasses by inedible or toxic exotic species;
• Destruction (via overgrazing) of riparian habitats that would otherwise provide up to 80% of the biomass productivity in arid grasslands;

The FAO Analysis of the Long-term Effects of Grazing (03N1)
In the FAO's projection of global food production during the period from 1998 through 2030, Chapter 12 by David Norse takes a surprising view of the effects of overgrazing on global food production and on the long-term effects of overgrazing generally. The views expressed are markedly at odds with the overwhelming consensus of virtually the entire scientific world on the long-term effects of overgrazing. Grazing lands, particularly rangelands, are seen by most as among the most degraded, if not the most degraded, of all the world's major ecosystems. This is not a minor issue because rangelands constitute something on the order of half of the world's 90 million km² of reasonably biologically productive lands, although productivities (production per unit area) tend to be significantly lower than the world's other major ecosystems. The following summarizes the major views expressed by Norse.

The importance of overgrazing has been misjudged in the past, particularly in sub-Saharan Africa.

• There is very little lasting impact (of overgrazing) on vegetation, which is more robust than once thought.
• Looking ahead to 2030, it is reasonable to assume that overgrazing will not cause major increases in land degradation globally.
• Some of the institutional and infrastructural constraints that have encouraged overgrazing in the past will be reduced as growing urbanization and income growth stimulate market improvements.

Much of the contents of this chapter provides counter-arguments to all of the above, but it seems worthwhile to summarize the main analyses.

• August L. Hormay, perhaps the leading range expert in the US, estimates that livestock grazing capacity has been reduced by 50% or more on western US grazing lands (70H1). This degradation was caused mainly by the extreme overgrazing that characterized the early days of settlement of the semi-arid and arid western US. To this author's knowledge, there is no data to support the view that this degradation has been reversed to any noticeable degree. After well over a century, it should probably be concluded that the damage is permanent. Argentina's Patagonia area was also subject to extreme overgrazing in centuries past and they remain badly degraded to this day. Much of the Middle East and eastern Mediterranean area were forested in past millennia. Overgrazing was a major cause of the deforestation. The forests of the region, for the most part, have never recovered.
• Riparian habitats are often the source of a large fraction of the productivity of rangelands - up to 80%. A joint BLM/ USFS report concluded in 1994 that "riparian areas have continued to decline [since 1934], and estimates that 20% of riparian areas managed by the BLM are "non-functioning", and 46% are "functioning at risk." Altogether, less than 20% of potential (original) riparian habitats in the semi-arid and arid portions of the western US still exist. Cheney, Elmore, and Platts wrote in "Livestock Grazing on Western Riparian Areas" (90C1), that "extensive field observations in the late 1980s suggest riparian areas throughout much of the West were in the worst condition in history." Obviously the extreme damage to riparian habitats of the western US of well over a century have not healed.
• The erosion sediments in western US rivers indicate that topsoil removals per unit of land area in western US rangelands are much higher than removals from regions of the US that mainly grow crops, even though grasslands are intrinsically more erosion resistant than croplands. It would take centuries to restore this soil. Although rangeland topsoil is of rather low-quality, it is still much better than organic-matter-free subsoil.
• Exotic inedible or toxic grass species are sweeping across the western US range. These species tend to start out in patches of badly overgrazed range where competition with native grasses is less. There is no reason for believing that this trend will ever be reversed, or that the effects on rangeland grazing capacity will never be significant.
• The massive growth (and migration) of deserts in China is widely attributed to overgrazing. Thousands of villages have been wiped out. "Desertification" affects a significant portion of the world's land, and is the cause of major reductions in land productivity worldwide.
• Microbiotic soil crusts blanket exposed soils in deserts, dry grasslands and shrub land worldwide (99G1). Recovery of these crusts after overgrazing takes on the order of a century. These crusts perform the major share of nitrogen fixation in such environments. Microbiotic crusts in arid ecosystems have been correlated with increased organic matter and available phosphorus (77K1), increased soil stability (72K1) (78R1) and increased soil water infiltration (72L1) (78R1). Crusts also play an important role in ecological succession because they provide favorable sites for the germination of vascular plants (84S2).
• Overgrazing in open forests results in replacement of grasses by woody shrubs. Shrub fires destroy the trees, while grass fires are harmless in this regard. Restoring the trees in a typical semiarid forest takes on the order of a century.
• Overgrazing on rangelands produces huge arroyos and gullies that tend to grow bigger over time, taking the topsoil with them.
• Overgrazing on rangelands tends to produce woody plants that greatly reduce the grazing capacity of the land. These plants are difficult and expensive to remove. Also they would probably take many decades (without any grazing) to return to a grass-covered environment.
• Income growth stimulates raising cattle in large feedlots and CAFOs and thus reduces grazing pressures in grasslands as the FAO's Norse implies. However large feedlots and CAFOs make the overall food supply system less efficient, and makes livestock manure less available to croplands, resulting in soil damage from excessive applications of chemical fertilizers and reducing soil organic matter contents on croplands. These effects are likely to become at least as harmful to global food supplies as overgrazing.
• Livestock populations tend to parallel human populations for obvious reasons. Increased population pressures on the land tend to encourage overgrazing. So it is far from clear that overgrazing may be expected to lessen over time as Norse predicts.

Below is a compilation of data pertaining to the issues alluded to above. Much more data can be found in "Grazing Lands Degradation: A Global Perspective," (07S1) also found on this website.

Net Primary Production (NPP) and Biomass of Grassland Biota (Global data)
(73W1), Ref. 23 of Ref. (78W1), p. 143 and p. 42 of Ref. (78W2))
(Columns 2, 6, and 7 Areas are in units of millions of km².)
(Col. 6 is from Ref. (79A1)) (Col. 7 is from Ref. (83O1).)
(NPP (Column 4) is in units of tonnes of carbon/ km²/ year.)

Agricultural stocking densities on the world's rangelands are about 10 times natural (wildlife) stocking densities (92O1). (Presumably the comparison is based on Animal Units (AU).)

Grazing more than 50% of a grass will quickly curtail root growth and severely limits future yields (US Utah extension agents James Barnhill, 801-399-8208 and Dean Miner, 801-370-8469, utah@ext.usu.edu, 1997). (The "50%" figure refers to 50% of the above-ground plant mass.)

Go to this Chapter's Table of Contents ~ Go to top of Section [B] (Some Basics)

Section [C] ~ PRODUCTIVITY AND DEGRADATION OF RIPARIAN ZONES ~
Riparian area and associated waterways cover 3 million acres (under 1%) of western public lands. In the US as a whole, riparian areas cover fewer than 5% of the land (p. 94 of Ref. (91J1)).

One study found that a riparian zone in eastern Oregon comprised 1.9% of the grazing allotment by area, but produced 21% of the available forage and 81% of the forage consumed by cattle ((82R2) in Ref. (99B1)).

Riparian zones typically represent 2-5% of a grazing allotment, but may supply up to 80% of forage used by cattle (94O1). Over-grazing of riparian areas causes soil compaction, reduced water infiltration, and reduced vegetation cover (94O1).

In the US Great Basin, all riparian lands cover fewer than 2% of the land area, yet receive 50% of livestock pressure. Riparian meadows occupy 1-2% of the interior northwest, but account for 81% of forage removed by livestock (p. 95 of Ref. (91J1)).

Ref. (94F2) reviews the US literature on the rate of recovery of riparian habitats following cessation of grazing. In general, the moister parts appear able to recover in a few years, whereas the drier peripheries take well over a decade.

Cows have damaged approximately 80% of the streams and riparian ecosystems in the arid regions of the western US (94U2).

Cheney, Elmore, and Platts wrote in "Livestock Grazing on Western Riparian Areas" (90C1), that "extensive field observations in the late 1980s suggest riparian areas throughout much of the West were in the worst condition in history." This is one of the most frequently cited papers in the range science literature and was written for the Environmental Protection Agency by three of the foremost fisheries and riparian specialists in the country. Author Wayne Elmore is a top riparian specialist for the Bureau of Land Management and William Platts is a nationally respected fisheries biologist with the US Forest Service (From a letter from Joy Belsky of 1/7/00 to the Atlantic Monthly regarding an article by P. Knize on grazing issues in the western US).

A 1999 study published in Journal of Soil and Water Conservation found that livestock grazing has damaged 80% of stream and riparian ecosystems in the western US. While these areas compose less than 1% of the overall landscape, 70-80% of all wildlife in the West depends on this habitat (01E1).

About 80% of all streams and riparian ecosystems in the arid West are severely degraded by livestock grazing. In its Global 2000 report, the Council on Environmental Quality noted, "improvident grazing ... has been the most potent desertification force, in terms of total area (351,562 square miles), within the US" (02R1).

US (western??) riparian areas are in the worst condition in history. Livestock are the major source of riparian degradation on western public lands. (1989 GAO report) (1990 EPA report) (99W1).

Extensive field observations in the late 1980s suggest that riparian areas throughout the western US were in the worst condition in history (from a 1990 Chaney report to USEPA) (p. 95 of Ref. (91J1)) (Ref. 49 of Ref. (91D1)) (90C1).

Southwest Center for Biological Diversity 6/29/99 reported in Journal of Soil and Water Conservation a summary of over 140 peer-reviewed scientific papers on the effects of grazing on western rivers and riparian areas. More than 100 papers found livestock grazing reduced water quality, compacted soils, increased sedimentation and harmed fish and wildlife. See http://www.onda.org/rippaper.html.

A joint BLM/ USFS report concluded in 1994 that "riparian areas have continued to decline [since 1934] (p. 25), and estimates that 20% of riparian areas managed by the BLM are "non-functioning", and 46% are "functioning at risk". Altogether, less than 20% of potential riparian habitats in the western US still exist. (See http://www.rangenet.org/projects/warcomments.html)

Forage utilization by livestock was 7.5 times higher in riparian meadows than in adjacent uplands (82B2) (97B2). A riparian zone in a forested watershed in Oregon comprised 1.9% of the allotment, but produced 21% of available forage and 81% of forage consumed (82R2) (97B2).

One US study (90S2) (97B2) found that grazed areas of a riparian meadow had 50% lower litter cover and 400% more bare ground than ungrazed areas. Soil surface litter is critical for slowing overland flow, promoting water infiltration, serving as a source of soil nutrients and organic matter, and protecting soil from freezing and erosive force of rain drops (97B2).

The extensive deterioration of western US riparian areas began with severe over-grazing in the late 19th and early 20th centuries. Native perennial grasses were virtually eliminated from vast areas and replaced by sagebrush, rabbit-brush, mesquite and juniper, and by exotic plants or shallow-rooted native vegetation less suited for holding soils in place (90C1).

Only a small portion of the tens of thousands of miles of riparian habitats in the Western US are in good condition. Poorly managed livestock grazing is the major cause of degraded riparian habitats on federal rangeland (p. 96 of Ref. (91J1)).

The US BLM estimates that 34% of its riparian areas are in proper functioning condition; 46% are functioning at risk, and 20% are non-functioning. ("Functioning at risk" means vegetation and soils are susceptible to losing their ability to sustain natural functioning biotic communities. "Non-functioning" means vegetation and ground cover are not maintaining soil conditions that can sustain natural biotic communities.) (94B2).

In uplands, grazing has fewer effects on shrubs than on grasses, but in riparian areas, grazing dramatically reduces the number and total biomass of shrubs and trees (which are crucial for shading streams, stabilizing stream banks and providing wildlife habitat (97B2).

Riparian areas in the western US have continued to decline since 1934 ((94U2) in (99B1)).

Riparian- and stream ecosystems represent 0.5-1.0% of the surface area of arid lands in the 11 western US ((90C1) in Ref. (99B1)).

Grazing by livestock has damaged 80% of the streams and riparian ecosystems in the arid region of the western US ((94U2) in Ref. (99B1)).

Riparian specialist Robert Ohmart (University of Arizona) questions whether weakened and degraded riparian communities throughout the arid West can "hang onto their thread of existence for another 30-50 years" while waiting for grazed systems to recover ((96O1) in Ref. (99B1)).

Less that 20% of potential riparian habitat in the western US still exists ((94U2) in Ref. (99B1)).

20% of the riparian areas managed by the BLM in the US are "non-functioning" and 46% are "functioning at risk" ((94U2) in Ref. (99B1)).

Four Arizona major drainages (Santa Cruz, San Pedro, San Simeon and Little Colorado) were once described as lush and green. These riparian areas are now dry along most of their lengths, except for violent floods draining from over-grazed rangeland -- no trees, very little grass, no beaver, trout or accumulated vegetation (p. 98-99 of (91J1)). The desert's flood-plain vegetation has changed almost beyond recognition in such areas as the Santa Cruz River Valley of Arizona (81S1). About 312 mi² of valley alluvium in the Santa Cruz and San Pedro Basins is undergoing "severe" erosion (over 9000 tonnes/ km²/ year) (Ref. 234 of (81S1)). The USDA estimates that 190 miles of stream banks in these basins are unstable due to over-grazing (81S1).

The Arizona Game and Fish Department reports that 97% of Arizona's original riparian habitats have been lost, with ranching being the major factor (p. 99 of Ref. (91J1)). Cottonwood regeneration along Arizona's Gila River Box Canyon was almost non-existent due to over-grazing. Arizona politics, however, required that the BLM's wildlife budget pay for fencing and replanting (89W1).

According to the Arizona State Parks Department, 90% of the original riparian ecosystems in Arizona and New Mexico are gone. Over 90% of Arizona's original riparian habitat is gone. 90% of the original riparian ecosystems in New Mexico are gone (p. 99 of Ref. (91J1)).

Before about 1880, the Gila River channel from Santa Cruz Junction to Yuma Arizona was narrow with firm banks bordered by cottonwoods and willows, but by the early 1890s, it occupied a sandy waste 0.25-0.5 mile wide (90W4)

Less than 3% of Arizona's original endowment of riparian vegetation remains, representing 0.001% of Arizona's land area (89W1).

A 1998 report from the New Mexico Environment Department to the US EPA concluded that nearly 85% of all stream miles in New Mexico violate state water quality standards, and that 96% of all water pollution in the state is from non-point sources. The report identified livestock grazing and agriculture as the leading causes of non-point source pollution (98U1).

California has lost 89% of its riparian woodlands since 1848, largely to ranching, farming, dams and mining (p. 99 of Ref. (91J1)).

Less than 5% of the riparian habitat in California's Central Valley remains: 85% of that is in disturbed or degraded condition (87F1).

About 90% of 5300 miles of riparian habitats surveyed in Colorado were rated in poor or fair condition due to livestock (p. 99 of Ref. (91J1)). A 1988 GAO report stated that 90% of the 5300 miles of streamside habitat managed by the BLM in Colorado are in unsatisfactory condition.

About 80% of the 12,000 miles of streams and associated riparian zones on BLM lands in Idaho are being damaged by poor management (p. 99 of Ref. (91J1)). About 80% of the Idaho BLM's riparian lands are degraded (George Wuethner, Sierra (Sept.-Oct. 1990)).

A BLM report on riparian habitats states that stream riparian habitats where livestock grazing is occurring have been grazed out of existence, or are in a severely deteriorated condition. Within Nevada, 883 miles of streams were identified as having deteriorated- or declining habitat (79F1).

The Wyoming Game and Fish Department estimates a loss of 45% of riparian area, largely from ranching (p. 99 of Ref. (91J1)). A 1988 study of 262 miles of Wyoming streams found only 2% functioning as in 1850. 83% were lost or destroyed by over-grazing and accelerated erosion (p. 92 of Ref. (91J1)).

Go to this Chapter's Table of Contents ~ Go to top of Section [B] (Some Basics) ~ Go to top of Section [C] (Productivity Degradation in Riparian Zones)

Section [D] ~ RANGELANDS DEGRADATION ~[D1]~ Global, [D2]~ Latin America, [D3]~ China, [D4]~ Middle East and North Africa, [D5]~ US, [D6]~ Central Asia, [D7]~ Asian Sub-Continent, [D8]~ Sub-Saharan Africa, [D9]~ Oceania,

An estimated 60,000 km² of productive land is lost to desertification every year (UN data) (06M1). This loss apparently does not include losses of productive land to salt buildup in irrigation systems, to urbanization, and to cropland abandonment due to erosion. These add about 40,000 km² additional land.

Over-grazing accounts for 35% of total land degradation worldwide (96M1). The bulk of these lands are probably semi-arid lands and arid lands, and these have a low productivity even when not degraded.

According to a 1991 UN assessment, (global) production losses from rangeland degradation accounts for $23 billion annually ($7 billion/ year in Africa. $8 billion/ year in Asia) (02E1).

In almost all developing countries, fodder needs now exceed the sustainable yield of rangelands (02E1).

The degraded area of the world's rangeland now totals 6.8 million km² (02E1). (This figure seems extremely low. The global area of rangeland is on the order of 40-50 million km².)

Degradation status of global land (croplands + permanent pasture + woodlands) based on work of Oldeman et al (Ref. 15 of Ref. (97C1)) and Dregne and Chou (Ref. 17 of Ref. (97C1)) (Land areas are in millions of km²)

From the estimates above, one can calculate the weighted average loss for each land-use category: 10.9% for irrigated land, 12.9% for rain-fed cropland, and 43% for range land (97C1).

Asia has the world's largest area of degraded dryland, 3.7 million km² (22% of Asia's dryland) ((97M3), p. 19).
Africa has 3.2 million km² of degraded dryland (25% of Africa's dryland) ((97M3), p. 19).
Europe has 1.0 million km² ((97M3), p. 19).

Overgrazing by livestock has caused as much as 20% of the world's pastures and range to lose productivity, which suggests that the global grass-eating livestock herd, now numbering 3.3 billion, is unlikely to increase much, if at all (91O1).

The great majority of the world's rangelands where precipitation is 10-30 cm./ year have been moderately to severely over-grazed for more than 50 years (85D1).

The UNEP Global Assessment of Soil Degradation Survey reveals that over 3 billion acres (12 million km²) (11% of the Earth's vegetated land) have been seriously degraded since 1945. Over-grazing by livestock accounts for 35% of this degraded land. Destructive agricultural practices account for 28% of global land degradation (92M1).

The rate of abandonment of drylands due to degradation is 90-110,000 km²/ year (Ref. 22 of Ref. (95D2)). Rates of degradation seem to be accelerating, particularly in developing countries (Ref. 23 of Ref. (95D2)).

The world's 3 billion ruminants (1 billion are beef cattle) are already overtaxing the Earth's grasslands, making it impossible for their numbers to continue to expand apace with human numbers. That "over-taxing" is the chief cause of the desertification that (according to the UN) threatens 1/8 of the Earth's land surface (Ref. 82 of Ref. (82W1)).

"There are very few arid land areas today that are being grazed within their carrying capacity". -- Jack D. Johnson, Director, Office of Arid-Land Studies, University of Arizona (Ref. 28 of Ref. (81S1)).

Fodder needs of livestock in nearly all developing countries now exceeds the sustainable yield of grassland and other forage resources (90B1).

Losses in livestock production ($billion/ year) from land degradation in dryland regions (Ref. 11 of Chapter 6 of Ref. (94B3) (?))

GLASOD provides the only comprehensive information about soil loss for grasslands (91O2). It reports that the world's "drylands" in the arid, semi-arid and dry sub-humid zones are particularly susceptible to soil degradation. These susceptible drylands constitute 55% of grasslands as defined by PAGE ((00W1), p.129). GLASOD found that slightly more than 10 million km² of all susceptible grasslands globally have been degraded by human activity ((97M3), p.19). Water causes 45% of this damage, and wind erosion causes 42% (00W2) ((97M3), p. 24).

Soil erosion rates may exceed 10,000 tonnes/ km²/ year in severely over-grazed pasture (Ref. 14 of Ref. (95P1)). (This is in the gully-erosion range. Gullies usually cause abandonment.)

Over 50% of the world's pastureland are over-grazed and subject to erosive degradation (Ref. 15 of Ref. (95P1)). ("pastureland" here probably includes grasslands (rangelands). These are generally more arid than pastureland.)

80% of the world's grasslands are suffering from soil degradation, and 20% of the world's drylands are in danger of becoming deserts. (According to a UN report on global ecosystems released in 9/2000. The $4 million study is the outcome of a program called Pilot Analysis of Global Ecosystems (PAGE)).

Over 40% of the particulate load of the world's rivers is carried by highly turbid waters - waters draining arid- and semi-arid regions (82M2). (Arid and semi-arid lands are predominantly grazing lands rather than croplands. In the US, rivers draining regions of predominantly grazing lands have sediment loads per unit area of drainage basin that are several times the national average.)

Reductions in land productivity by as much as 90% were reported for several areas during the 1977 UN Conference on Desertification (Ref. 23 of Ref. (81C2)). (Desertification is predominantly an arid lands problem. Grazing lands are predominantly semi-arid and arid lands.)

Most of the world's 31 million km² of grazing lands are overgrazed (82W1) and (81S1). (More recent data give significantly larger figures for grazing lands area, and also consider pastures [typically hilly land in more humid climates].)

The capacity of Mexico's rangeland is 11-22 ha/ cow (4.5-9.0 cows/ km²) but average livestock density is 17-33 cows/ km², producing serious soil erosion (Ref. 97 and 98 of Ref. (90W1)).

The 1 million km² Gran Chaco in Argentina, Paraguay and Bolivia, have turned to thorny shrubs from over-grazing. The carrying capacity is now 5-50 cows/ km² (p. 117 of Ref. (90W1)).

Dry Chaco rangeland (Argentina) is degraded by shrub-invasion and salinization. Patagonia (Argentina) grasslands are over-grazed by sheep (90W1).

The Coatingo in northeastern Brazil covers 800,000 km² of thorn-scrub vegetation. It supports a large portion of Brazil's cattle and a large goat population. Centuries of over-grazing, fire, agriculture and torrential rains have seriously eroded the shallow soil on most of the Coatingo (p. 116 of Ref. (90W1)).

Thorn-scrub rangeland in northeastern Brazil is over-grazed by goats and cattle, and has suffered soil erosion and salination (90W1).

The foothills of the western Andean range are bare, and support only a thin grass cover during sporadic rainfall periods. That cover is depleted rapidly by grazing sheep. Sporadic rains cause gullies and landslides, often resulting in property damage and death, and cutting the road linking Lima Peru with the central Sierra (90H3).

Cultivated pastures occupy up to 76% of Costa Rica's land suitable for annual crops. Pastures in Costa Rica on infertile lands with sharp relief are short-lived and provoke severe erosion (90W1).

Capacity of Mexico's rangelands is 4.5-9 cows/ km², but the average livestock density is 17-33 cows/ km². Over-grazing has caused serious soil erosion on Mexico's rangelands (Refs. 97, 98 of Ref. (90W1)).

Grazing-provoked soil erosion is common in dry regions of Mexico; erosion and hydrologic changes follow forest conversion to pastures, particularly on steep slopes (90W1).

Goat/ sheep grazing on dry rangelands in Mexico is reducing tree cover and increasing soil loss (90W1).

Weed invasion limits range productivity in dry regions of Mexico (90W1).

In the savannas of northern and central Mexico, the livestock density is nearly four times the land's carrying capacity (Ref. 47 of Ref. (91D1)).

A comparison of livestock populations reported in the 1960 census from Coahuila (in Mexico) with the potential carrying capacity under "good" conditions of vegetation indicates that close to 50% general overstocking exists (70X1).

Mexico's communal tenure system followed the 1910 revolution. Ejidas (where poor people graze their animals) currently occupy 250,000 km² in northern Mexico. In one 21,000-acre (85-km²) ejida, proper stocking is 387 AU (782 if it were in excellent condition). Actual stocking is 1100 AU (86L1).

Patagonia (in southern Argentina) was settled in the 19th century. Its sheep ranches helped make Argentina one of the world's wealthiest countries. Over-grazing turned Patagonia into a barren plateau reminiscent of South Dakota (94N1).

Of all the changes blowing through Patagonia, though, none has had greater impact than the shifts in ownership and use of the land brought about by the collapse of the huge sheep farms, or estancias, of the Argentine tableland. Stretching nearly 1500 miles (2400 km) from the Río Colorado in the north to Tierra del Fuego in the south, this immense arid wilderness - the steppe - is the heart of Patagonia. Its culture and economy were built on sheep. But since the 1970s falling wool prices and desertification caused by overgrazing have brought the sheep-raising industry in Patagonia to its knees. Hundreds of estancias have gone out of business. Others have been sold to wealthy foreigners. Nearly one-sixth of the Argentine Patagonia now belongs to 350 foreign owners, many of them Americans (04W1).

For decades, sheep have over-grazed Patagonia's rangelands of lower Argentina -- 900,000 km² are grazed by 16 million sheep (18 sheep/ km²) (3.6 AU/ km²) (90W1).

Patagonia (southern Argentina) was settled in the 19th century. Its sheep ranches helped make Argentina one of the world's wealthiest countries. But decades of over-grazing have turned Patagonia into a barren plateau reminiscent of South Dakota (94N1).

After the 1978 economic reforms, when China shifted to a market economy, the government lost control of livestock numbers. Livestock populations then grew rapidly, to numbers far exceeding those in the US, a country with comparable grazing capacity. E.g.
Cattle: US - 97 million: China -- 128 million.
Sheep/ goats: US - 8 million: China -- 290 million (Sheep and goats are better suited to degraded grassland because their teeth can cut grass closer to the soil.) (UNFAO, FAOSTAT Statistics database at www.aps/fao.org 5/28/02) Thus abnormally high populations of sheep and goats are probably an indicator of degraded grasslands.

In Gonge County (eastern Qinghai Province of northwestern China) the number of sheep that the local grassland can support is estimated at 3.7 million. At the end of 1998 the region's flock had reached 5.5 million (00E1) (01B2) (02E1).

China is planting 26 million acres (105,000 km²), 10% of its grain-growing area, with trees. But many die because the soil is already too thin (03L1).

A human population of 1.3 billion and a livestock population of just over 400 million are weighing heavily on China's land. Huge flocks of sheep and goats in northwestern China are stripping the land of its protective vegetation, creating a dust bowl on a scale not seen before. While over-plowing is now being partly remedied by paying farmers to plant their grain land in trees, overgrazing continues largely unabated. China's cattle, sheep, and goat population tripled from 1950 to 2002. The US, a country with comparable grazing capacity, has 97 million cattle. China has 106 million. But for sheep and goats, the figures are 8 million (US) versus 298 million (China). (See data at http://www.earth-policy.org/Updates/Update26_data.htm) (03B1).

In addition to the direct damage from over-plowing and overgrazing, the northern half of China is literally drying out as rainfall declines and over-pumping depletes aquifers. Water tables are falling almost everywhere, altering the region's hydrology. Thousands of lakes in northern China have disappeared (based on US satellite data over 30 years) (01B2).

After centuries of nomadic grazing, sedentary grazing predominates in China. Native rangelands are deteriorating. In many areas, over-grazing has led to loss of climax species, plant vigor and production. China's grassland (steppe range or pasture) occupies 3.6 million km² -- 37.1% of China's land area (82B1).

Over 33% of China's rangelands are over-grazed (93L1), (96M1). (This seems low, but it is higher than 1989 (23%).)

Over-grazing affects 510,000 km² (23% of China's total grassland). Biomass productivity on China's grasslands has dropped 30-50% since the 1960's (89C1).

In 13 of 15 Arab Nation States over-grazing accounts for more than 35% of land degradation. For 7 of the 17 Arab Nation states overgrazing accounts for at least 75% of land degradation, with Saudi Arabia, Libya and Jordan at the top of the list (96M1).

Plant cover has disappeared in many steppe zones in Syria, Jordan, Iraq, the U. A. R. and Iran. Rangelands there have become semi-deserts of gravel or semi-sand (81B1).

Rangelands in Iran had deteriorated 33-50% by 1970. Niknam's 1970 estimate of 4 times over-stocking in Iran is conservative. 1,000,000 km² of rangeland in Iran carried 84 million sheep units in 1970. Carrying capacity in 1970: 21 million sheep units (78K1).

Forests cover 180,000 km² (11%) of Iran's 1,650,000 km². Herbaceous cover is over-grazed and depleted nearly everywhere in Iran. Topsoil, sometimes shallow over rocky subsoil, has gone from large tracts of once forested lands (74S1).

A UN report on the Middle East in the fall of 1977 reported that the natural range lands in the north of Iraq are able to support 250,000 sheep, but contain 4 times that many (78B1) (81B1).

A UN report on the Middle East in the fall of 1977 reported that the arid- and semi-arid natural rangeland zones in Syria contain three times the amount of livestock that can be sustained (78B1) (81B1).

In Tunisia, Algeria and Morocco, rangelands are populated by three head of cattle in an area where only one could thrive (UN report) (p. 362 of Ref. (91J1)).

The evolution of vegetation on Algeria-Tunisia's high plains is shown schematically in Ref. (70L1). Vegetation in the arid zone of North Africa has experienced accelerated deterioration since around 1930. This deterioration results from the great population pressure (intense over-grazing), the extension of episodic cereal-growing, and the removal of woody species for firewood (1 kg./ person/ day = 0.5-1.0 ha. of woody vegetation/ person/ year (70L1). Climate change is not a cause (70L1).

Very few grass-dominated natural ecosystems remain in North Africa, except for esparto grass (which is almost unpalatable). Palatable perennial grasses and legumes have been eliminated by centuries of overstocking (80L1).

Three times as many cattle are being grazed as are sustainable in Tunisia (89P2).

An explosive growth of livestock numbers - from 28.6 million in 1961 to 134.6 million in 2004 - has resulted widespread degradation of rangeland in Sudan. The problem is attributed to inadequate land tenure, resulting in the people who manage the land having little incentive to invest in, and protect, the land (07U1). The doubling of human population every 2-3 decades may also have had an influence.

More than 100 years of (US) livestock grazing has resulted in serious depletion in nitrogen stores in the soils (due to destruction of the microbiotic crust, losses of nitrogen from volatilization from urine and manure, consumption of nitrogen (in plant leaves) by livestock that are taken away to stockyards, and increases of de-nitrification due to soil disturbance). Additional losses of nitrogen from shrub- and juniper-burning programs may push extensive plant communities over "thresholds" into new and permanently degraded stable states (97B3).

The book The Changing Mile (85H1) promoted the idea that the international borderlands of southern Arizona and northern Sonora of Mexico suffered an increase in aridity in the 19^th century and argued that the observed vegetation changes in the area were caused by this aridity change - not to human land-use changes (massive overgrazing) (94F2). More recent studies (91B2) concluded "probably no single land use has had a greater effect on the vegetation of southeastern Arizona, or has led to more changes in the landscape than livestock grazing range management programs. Undoubtedly, grazing since the 1870s has led to soil erosion, destruction of those plants most palatable to livestock, changes in regional fire ecology, the spread of both native and alien plants, and changes in the age structure of evergreen woodlands and riparian forests". Bahre (91B2) also concluded "the present historic evidence...casts serious doubt on the hypothesis that a shift toward greater aridity is the primary factor for regional vegetation changes" (94F2).

Grazing is credited with transforming southern New Mexico from grassland to creosote bush desert (38W1) (69Y1) (94F2).

Grazing in the western US occurs in creosote bush deserts, blackbrush deserts, slickrock mesas, sagebrush flats, pinyon-juniper woodlands, chaparral, ponderosa pine forests, and alpine meadows above timberline (94F2).

Cheney, Elmore, and Platts (90C1) state "In 1980, the US Department of Agriculture estimated that the vegetation on more than half of all western US rangelands was deteriorated to less than 40% of potential production, and to less than 60% of potential on more than 85% of the rangeland." (From a letter from Joy Belsky of 1/7/00 to the Atlantic Monthly regarding an article by P. Knize on grazing issues in the western US).

The US Soil Conservation Service says more than 410 million acres (1.66 million km²) of public and private grazing lands are in unsatisfactory condition -- 21% of the US land outside of Alaska. Nearly all these degraded lands are in the Western US (99W1).

Although there may have been some improvements in grazing management, the increase of cattle in the Western US [doubling over the past 5 decades] suggest that grazing impacts will continue into the foreseeable future (95T1) in (99B1)).

A 1990 BLM report stated that "the public range was in the best condition yet this century, and improving." A 1991 GAO report countered that "We could not confirm BLM's conclusion that the public rangeland is in better condition than ever before in this century because the historic studies BLM relied upon were prepared using different methodologies in some cases, and in other instances did not contain supporting documentation." (99B1)?

Livestock grazing is the fourth major cause of species endangerment in the US and the second major cause of endangerment of plant species ((94F1) in Ref. (99B1)).

The US SCS estimates that less than 50% of the original rangeland topsoil of the western US remains (p. 78 of Ref. (91J1)).

Exclosure studies in forested ecosystems in the Interior US West consistently find that livestock substantially reduce vegetative cover, especially that of perennial bunchgrasses. In a Bitterroot Mountain study, grazing reduced the productivity, frequency and cover of several perennial bunchgrasses by 50-100%, and increases in annual grasses and perennial weeds was not enough to make up the difference (97B2).

In 1980 the US Department of Agriculture estimated that the vegetation on more than 50% of all western rangelands was deteriorated to less than 40% of potential productivity, and to less than 60% of potential productivity on more than 85% of these rangelands (90C1).

The US SCS reports (1981) an average US topsoil erosion rate of 4.2 tons/ acre/ year on grazed forest, and 3.1 tons/ year on grazed rangelands. Pimental suggests that range soil is eroding 20 times faster than it is being replaced (p. 79 of Ref. (91J1)). US pastures lose 600 tonnes/ km²/ year of topsoil (Ref. 13 of Ref. (95P1)).

Half of US rangeland is severely degraded (91D1).

August L. Hormay, perhaps the leading range expert in the US, estimates that livestock grazing capacity has been reduced by 50% or more on western US grazing lands (70H1).

The Great Plains of the US once supported 200-250 cattle/ mi² (77-96/ km²). The dust bowl disaster prompted federal grazing regulations leading to today's cattle densities of 50-100 head/ mi² on the same ranges. Despite these regulations, as much as 28% of the 163 million acres of federal rangelands have been made almost useless by over-grazing and are in poor condition according to the CEQ (77B1).

A GAO report (CED-77-88, $1 from USGAO Distribution Section, P.O. Box 1020, Washington DC 20013) claims that the quality of US public rangeland continues to deteriorate, and that the problem is "principally poorly-managed livestock grazing" (77U1).

The US Council on Environmental Quality (CEQ) reported 1/3 of US range land (exclusive of Alaska) in fair condition, and 1/3 in poor condition (Ref. 21 of Ref. (84B1)).

15-25% of US range lands are undergoing serious degradation from improperly controlled livestock grazing (93H1). 35-40% of US range lands are either stable or in very slow decline (93H1).

Over-grazing of US range lands accounts for the fact that about 70% of western US grazing lands are producing under 50% of their forage potential (Ref. 1 of Ref. (78D1)).

About 70% of western US grazing lands are producing at less than 50% of their potential -- a result of past over-grazing (78D1).

About 54% of US pastureland is over-grazed and is subject to high rates of topsoil erosion (Refs. 25 and 26 of Ref. (95P1)).

Half of US range land is considered severely degraded, with its livestock-carrying capacity reduced by at least 50% (Ref. 26 of Ref. (95D1)).

Of 410,000 mi² of US public rangeland, 30.5% is in poor condition, 50% is in fair condition (72H1). 50% of federal rangelands are in a state of severe-to-critical erosion; 32% are eroding moderately, and 18% have slight- or no erosion (72H1).

According to USDA analysts, close to 1/3 of all non-federal rangeland was over-grazed in 1976 (Ref. 66 of Ref. (82W1)). Of the 27% of western grazing lands that are in private ownership, 68% is in fair or poor condition (1975) (86J1).

A 1990 BLM survey found 33% of US grazing lands to be in good or excellent condition (Ref. 6 of Chapter 6 of Ref. (94B3)).

The vast bulk of US range that agencies term "satisfactory" is producing biomass at less than 50% (some less than 20%) of its pre-livestock rate. By industry standards, an allotment rated in 100% "excellent" condition may still be only 50% as productive as it was originally (p. 442 of Ref. (91J1)).

In the US, shrub land range is in worse shape than grassland range; 55% is producing at less than 40% of its biotic potential, and 85% is producing at less than 60% of potential (p. 57 of Ref. (91J1)).

Vegetation on more than half of all western range lands in the US has deteriorated to less than 40% of potential productivity, and 85% has deteriorated to less than 60% of potential productivity (from a 1990 report prepared for US EPA by Chaney) (p. 66 of Ref. (91J1)).

Of western US BLM lands for which data were available (80%), over 71% (340,000 km²) is in "unsatisfactory" condition (producing at under 40% of its present (as opposed to pre-livestock) biological potential (91J1).

The BLM is quoted as writing: "There is very little of the western range where, because of the destruction of the plant-cover by improper management, accelerated erosion has not destroyed a portion of the soil mantle and thus reduced the total productivity of the site" (75W1).

West Texas was once covered by mid-grass prairies, but now is covered by prickly pear cactus and mesquite trees. This shows how damaging livestock grazing can be, in spite of relatively high rainfall and grazing-adapted plants (00B1).

Most of California's once-lush grass- and flower-carpeted hills and valleys are covered with sparse, over-grazed exotic grasses, "weeds" and bare dirt (p. 65 of Ref. (91J1)).

2.2 million acres in the foothills and mountains of (California's) San Joaquin Basin are under moderate-to-severe water erosion (sheet- and gully type) as a result of over-grazing (Ref. 149 of Ref. (81S1)). W. O. Beatty of the US SCS, claims that grazing lands along the west rim of the San Joaquin Basin are still deteriorating (81S1).

Of the 4 million acres (16,000 km²) of private rangeland in (California's) San Joaquin Valley, 80% had problems with over-grazing (erosion, invasion of weeds and brush). Of the public (USFS) rangelands in the San Joaquin Valley, 102,000 acres (17%) had over-grazing problems. The 400,000 acres (1,600 km²) of BLM lands there are thought to be in the same condition as private land (Ref. 144 of Ref. (81S1)).

The 3.9 million-acre Rio Puerco River Basin (40 miles NW of Albuquerque) is one of the most eroded and over-grazed river basins in the arid west. It began around 1900, and has yet to recover. Water tables began dropping in the late 1880s, arroyo-cutting began, and sediment flowed (1.1-1.5 billion tons into the Rio Grande during 1885-1962 (81S3)). During 1931-38 the bed of the Rio Grande River rose 5 ft. down-stream of the mouth of the Rio Puerco (Ref. 50 of Ref. (81S1)). The BLM projects that the vegetation in (New Mexico's) Rio Puerco Valley that is in poor condition will increase from today's 85,651 acres (347 km²) to 170,700 acres (691 km²) by 2000 under current grazing practices. Land suffering "moderate" to "severe" soil erosion will increase to 360,550 acres (1460 km²) (73% of the public land in the valley) (Ref. 34 of Ref. (81S3)). By 1950, all settlements in the Rio Puerco valley had become ghost towns. In the late 1930s the average arroyo was 35' deep and 120' wide (81S3).

In the Gila and Aldo Leopold Wilderness areas in New Mexico, the USFS has permitted continued severe overgrazing, dozens of new permanent grazing improvements, such as stock tanks, and inappropriate use of mechanized equipment. In one incident, the allottee used a bulldozer to channelize a wilderness stream to maintain water flow to stock tanks. The permit holder is an East Texas bank that acquired the grazing permit when it foreclosed on the allottee (94D1).

About 70% of rangelands in the Interior Columbia Basin are rated as having "low ecological integrity", 70% of Basin streams and riparian areas are classified as being "non-functional" or "functional at risk", and 5% are rated as having "high ecological integrity" (97B3).

In Bear Creek watershed (Eastern Oregon), over-grazing has caused extensive sheet- and gully erosion, destruction of all but a few perennial grasses, and the invasion of sagebrush and cheat grass (75W1).

The steppe-like grassy plains in portions of Idaho and eastern Oregon and Washington are now commonly barren and eroded (p. 65 of Ref. (91J1)).

The Challis Planning unit of the BLM (in Idaho) has 352,000 acres. Soil erosion is rampant. 52% of the area has undergone "moderate" to "severe" soil erosion. Pedestaling, rills and gullies are readily apparent. Widespread is the absence of plant litter to stabilize soils and help germinate seeds (Ref. 47 of Ref. (81S1)).

Quote of Wm. R. Meiners (resource management specialist of 30 years for the USFS, SCS, BIA and BLM) in a court deposition concerning conditions in the 321,000-acre Challis Planning Unit of the BLM on the East Fork of the Salmon River (Idaho): "The public lands of this unit, and particularly those along the East Fork, are among the most abused lands I have ever seen in my professional career. Grazing pressures have reduced the land along the river to almost a bare-ground status. Erosion is evident; topsoil has been lost; meadows have been beaten into the ground." (75W1).

In the Saylor Creek Unit of (Idaho's) Boise Grazing District (1000 mi²), over-grazing has been a major contributor to pollution and sedimentation in Saylor Creek and the Snake River (75W1).

The 15 million-acre Navajo Indian Reservation can safely support 16,000 sheep at most. 140,000 sheep graze there (Ref. 38 of Ref. (81B1)) (77B1).

In a large area of west Texas and eastern New Mexico over the past 100 years, large areas of black grama grassland have been replaced by communities dominated by shrubs, especially creosote bush and mesquite (Refs. 12, 13, 14 of Ref. (90S1)). Heavy grazing during the short summer wet season contributes to loss of grass cover during moderate drought and to lowered competitive potential of grasses (Ref. 24 of Ref. (90S1)).

In Gaines Co. Texas, about 25% of the rangeland area appears to be over-grazed (81S1). 10000-15000 acres (40-60 km²) of the remaining natural grassland are plowed annually to plant more cotton. Rainfall (16"/ year) is so low that dryland farming is a losing proposition and subject to much wind erosion (81S1).

Late in 1999, Texas pastures were 88% poor to very poor, according to the state's Agricultural Statistics Service (99B2).

In late 1999 Oklahoma's pastures were 38% poor to very poor (99B2).

In late 1999 Kansas' pastures were 26% poor to very poor (99B2).

Support for George Wuerthner's statement that private grazing lands are more degraded than livestock-grazed public lands:

• In the publication, Montana Rangeland Resource Program put out by the Montana Dept. of Natural Resources and Conservation, it has a chart on page 27 that compares rangeland condition by land status. Non-federal land was rated with 59% in good to excellent condition and 41% in fair and poor condition. BLM had 71% in good and excellent and 29% in fair and poor. Forest Service was 72% in good and excellent and 28% in fair and poor. (Bear in mind that Montana has some of the best condition range in the West due to generally higher precipitation and lower evaporation. Still, clearly, private lands are in worse shape than the public lands.)
• In Forest Service General Tech. Report 181 "An analysis of the land base situation in the United States", the condition of the 405 million non-federal lands has 16.4 million acres in excellent condition, 120 million acres in good, or approximately 136.4 million acres in satisfactory condition, while 182 million acres in fair condition and 66 million acres in poor condition or 242 million are in unsatisfactory condition, plus another 20 million acres in "other" which is usually lands that would be in poor condition. By comparison BLM acres have 6.6 million in excellent, 49 million acres are in good or 55.6 million in satisfactory condition and, 66 in fair, and 49 million in poor condition or 114 million in unsatisfactory condition with 11 million in "other". Forest Service lands had 40.7 million in satisfactory condition that equals good-to-excellent, and 10.5 million acres in unsatisfactory or fair-to-poor. So total federal lands is 106.3 million in satisfactory condition and 124 million in fair to poor condition. You can figure out the percentages, but clearly, a higher percentage of non-federal lands is in fair-to-poor condition than federal lands.
• When you consider that private lands are, on the whole, a lot more productive, better watered, etc. thus less vulnerable to abuse and recover much more quickly, these figures are not reassuring.

Privately owned grazing lands tend to be more productive and better watered than public grazing lands, and thus intrinsically more resistant to grazing abuses (99W1).

On Coronado National Forest, the US Forest Service has calculated that its lands are overgrazed by at least 73,000 AUMs (85C1). (AUM = Animal-Unit-Month)

Toyabe National Forest in the US contains 3.2 million acres (13,000 km²), with 1.1 million acres classified as suitable for livestock grazing. The USFS reports that another 250,000 acres of unsuitable range is currently being grazed by livestock. 40-45% of Toiyabe rangelands are in poor condition, more than any other US national forest (89U1).

Of the 9200 grazing allotments in the US Forest Service's 6 western regions, range managers have identified almost 2,200 that they consider to be in a declining condition and/or overstocked. 104 million acres of USFS-managed grazing land are divided into 9752 grazing allotments (9217 are in 6 western districts). The US Forest Service (USFS) has classified about 50 million acres (202,000 km²) within the 104 million acres (421,000 km²) of grazing allotments as suitable for livestock grazing (91D2).

Significant portions of the sagebrush-grass rangelands of the Great Basin (US) have been degraded to where they produce under 50% of their potential (Ref. (84E1) in Ref. (99G1)).

In the 520-km² Monticello Grazing District of southern Utah, the natural ground cover has been almost totally destroyed, leaving desert lands and creating erosion gullies so long and deep that they are often used as roads (75W1).

Of 106 small pastures studied along the Wasatch Front in Utah, 44% were over-grazed. (U.S. Utah extension agents James Barnhill, 801-399-8208 and Dean Miner, 801-370-8469, utah@ext.usu.edu, 1997).

North Dakota has 1.1 million acres (4450 km²) of grazing land affected by leafy spurge (vs. 932,000 acres in 1991). Leafy spurge crowds out prairie grass, rendering pastures useless (Wall Street Journal (6/15/99)).

An extensive scientific literature going back many years (i.e. (51P1), (81M1), (87L2), (90L2), (94Y1), and others cited in Sheley (94S1) (see Ref. (97B3)), suggests that livestock grazing is the major cause of the spread of weeds in rangelands in the western US. Livestock disturb the soil, create micro-sites for weed seed germination, increase soil temperatures, pulverize microbiotic crusts that prevent the establishment of weeds, reduce the vigor and competitive ability of native plant species, and transport weed seed from infested areas into non-infested areas. One study, for example, found that one cow transported over 900,000 viable seeds from 36 different weedy species in her gut and coat in a single season (42D1) in Ref. (97B3)).

In the intermountain West (US), exotic forbs have invaded over 400,000 km² of rangeland (99G1).

Long-term monitoring suggests that some weed-altered arid communities in the US may never recover, even with cessation of all disturbances ((90B2) in Ref. (99G1)).

Arid portions of the Pacific Northwest have been invaded by over 860 exotic plant species, over 40% of the estimated 2000 exotic plants currently recorded in the entire US. (See Ref. (99G1)) Of these, 115 have been declared "noxious weeds" by one or more states (99G1).

The spread of exotic weeds throughout the grasslands, shrub-lands, woodlands and shrub-steppe of the Intermountain West in the US has been described as one of the greatest environmental threats facing native species and ecosystems of the region (89M1), (90B2), ((98W1) in Ref. (99G1)).

One of the most devastating consequences of weed invasions in the Intermountain West in the US may be the absence of community recovery once flammable weeds produce a permanently shortened fire-return cycle (78Y1), (90B2), (90W2) in (99G1).

In Kalmykia in Russia's semi-desert zone, moderately and greatly trampled pastures make up 66% of pastureland. The productivity of trampled pastures is 3-5 times less than that of pastures under moderate grazing (03S1).

Forage reserves of lichens in Russia have shrunk by 2-3 times in reindeer pastures since 1950 (03S1).

The degradation of Russia's pastures and hayfields is constantly increasing and hayfield areas are shrinking (03S1). Between 1986-90, about 24 million tonnes of hay were harvested annually, vs. 17.7 million tonnes in 2000 (03S1).

The productivity of Russia's pastures and hayfields is constantly decreasing. Currently, it is 70-100 tonnes/ km² of green mass for hayfields and 200-400 tonnes/ km²/ year for pastures. Low productivity can be explained by the fact that 70% of these degraded lands, which are covered with shrubs, low forests, tussocks and swamps, are located on saline soils and solonetz complexes. More than 50% of Russia's hayfields and pastures require improvement (03S1).

Studies in Buryatia and Chita Oblast in Russia (just north and northeast of Mongolia) and in Inner Mongolia in China (just south and east of Mongolia suggest that as much as 75% of grasslands have suffered some degree of degradation ((99H1), p. 52) ((96G1), p. 21). Chinese government figures say 44% of Inner Mongolia's grasslands are useable and in good condition ((99N1), p. 426).

The yield of forage from Inner Mongolia's rangelands has declined by at least 30%, and as much as 70%, over the past half-century. If trends continue, Xilingol will be uninhabitable in 15 years (01U2).

In Mongolia's grasslands, moderate or severe degradation affects 4-20% of pasturelands ((95G2), p. 28). (The far better condition of Mongolia's grasslands relative to those of adjacent Inner Mongolia, Buryatia and Chita Oblast are attributed by Ref. (00W1) to Mongolia's mobile herding practices vs. the more stationary (sedentary) practices found in grasslands of Mongolia's neighbors.)

In India, demand for fodder in 2000 was estimated at 700 million tons, vs. a sustainable supply of 540 million tons (01B3) (02E1).

In the grazing land of one district of the central Himalayas in India, livestock populations exceed the carrying capacity of the land by a factor of 4.5 (Environment, 29(3) (1987) p. 11).

In the Indian state of Rajasthan and Karnataka, fodder supplies for grazing animals satisfies 50-80% of need, leaving large numbers of emaciated, unproductive cattle (Ref. 10 of Chapter 6 of (94B3)).

Persistent overgrazing has reduced forage production in Pakistan's rangelands to one-third the potential (a loss of almost 50 million tonnes/ year), and in some areas to as low as 15% of potential forage production ("Pakistan Rangelands Degradation," The Peninsula -- Qatar's Leading English Language Daily Web posted 6/3/2006.).

A study of grassland conditions in 9 countries of southern Africa reports that cattle numbers exceed carrying capacity in each country by 50-100% (Ref. 22 of (88B1)).

Water conflicts between farmers and pastoralists will persist if the in-migration of farmers to former pastoral lands is not controlled. The squeezing of pastoralists into ecologically poor, marginal lands of Tanzania's Pangani River basin has continued unabated since the 1930s, even as the population of pastoralists and their livestock has grown (07M1).

Nearly 20% of Niger's land area is at risk of desertification (" Land resource stresses and desertification in Africa," NRCS (2001)).

The large and growing numbers of livestock and the cultivation of the lowland's more marginal lands have accelerated land degradation in the Pangani River basin of Tanzania (07M1).

Nigeria is losing 2330 km² /year of grazing lands and croplands to deserts. In Senegal, 500 km²/ year are being lost to deserts (06L1). This does not mean that the desert is growing of its own accord. Overgrazing, over-plowing and deforestation are creating vegetation-free zones that permit sand dunes to migrate. Nigeria's human population was 33 million in 1960 and 132 million in 2005. Nigeria's livestock population has increased from 6 million in1960 to 66 million in 2005.

The forage needs of Nigeria's 15 million cattle and 51 million sheep and goats exceed the sustainable yield of Nigeria's grasslands (06B1).

Over 50% of Kenya's grazing lands are badly eroded (83T1).

Overgrazing has seriously damaged vast areas of Kenya's semi-arid grasslands (76E1).

In eastern Kenya, a study found that rangeland with over 20% vegetative cover erodes at 600-1200 tonnes/ km²/ year, while the rate for land with under 20% vegetative cover is several times larger (95W1).

Since 1880, much of Kenya's forests had been destroyed. Intense erosion has occurred in Kenya's deforested highlands. Mountains and hills are now masses of bare rock due to fire, over-grazing, and over-cropping. The Kenya Land Commission concluded in 1934 that sectors of the reserves of Turkana and Suk -- and probably Wakamba and Mbere -- were eroded by over-grazing to the point where it may be impossible to regenerate the pastures (44H1).

Invasion by woody plants resulting from over-grazing has rendered 30,000 km² of South Africa useless for cattle. An additional 140,000 km² of savanna is rapidly losing its ability to support livestock as scrubby brush spreads across South Africa (91D1).

Wells drilled in grazing lands in Botswana are causing water tables to drop steadily, forcing herders to migrate or give up their stock (State of the World (1989) p. 63).

3 million cattle in western Rwanda have badly eroded hillsides and have accelerated the damage to soil productivity. (The economy is almost entirely based on agriculture and livestock.) (Dejan Kovarevic, Pittsburgh Post Gazette (4/19/94)).

In Western Australia, about 1/3 of pastoral lands is over-grazed (83C2).

In large portions of New Zealand's North Island, "slips" (huge slabs of topsoil) are sliding off over-grazed hills (p. 357 of Ref. (91J1)).

Instability of soil in some parts of New Zealand, notably in foothills of mountains bordering South Island's Canterbury Plains, in Whangamomona County, and the Gisborne district of North Island has no equal in world in terms of accelerated erosion. Much of the accelerated erosion is due to over-grazing by sheep, particularly in New Zealand's South Island (75S1).

Over-grazing has produced almost complete destruction of vegetation on parts of Torlese Range and in Craigieburn Mountains of Canterbury, as well as in other parts of New Zealand's North- and South Canterbury (75S1).

Go to this Chapter's Table of Contents ~ Go to top of Section [B] (Some Basics) ~ Go to top of Section [C] (Productivity Degradation in Riparian Zones) Go to top of Section [D] (Rangeland Degradation Data)

Microbiotic soil crusts are also referred to as biological, cryptobiotic, cryptogamic, or microphytic crusts.

Living crusts of lichens, mosses, algae and cyanobacteria blanket exposed soils in deserts, dry grasslands and shrub-land around the world (99G1).

Microbiotic (cryptogamic) soil crusts are delicate symbioses of cyanobacteria, lichens and mosses. These crusts perform the major share of nitrogen fixation in desert ecosystems (78R1). The availability of nitrogen in the soil is a primary limiting factor on biomass production in deserts. In the Great Basin Desert of the US, it is secondary in importance only to the lack of moisture (78J1). Microbiotic crusts in arid ecosystems have been correlated with increased organic matter and available phosphorus (77K1), increased soil stability (72K1) (78R1) and increased soil water infiltration (72L1) (78R1). Crusts also play an important role in ecological succession because they provide favorable sites for the germination of vascular plants (84S2).

Observations of recovery of cryptobiotic crusts from trampling by livestock at three sites in Utah yielded estimates for full recovery of 45-85 years. Moss recovery was much slower than that of the lichens. At two of the three sites where mosses were found, no moss recovery at all was seen. At the third site, where some recovery was seen, full recovery of moss cover would take over 250 years at the observed rate of recovery (93B3).

Microbiotic crusts typically grow on the interspaces between grasses and shrubs throughout the Great Basin Desert, the semi-deserts of the Colorado Plateau and in many pinion-juniper communities of Utah, Nevada, Arizona, Colorado, New Mexico and Wyoming. These soil crusts reduce soil erosion, act as a mulch trapping moisture in the soil, capture atmospheric nitrogen and make it available to soil and plants, and prevent the germination of seeds -- particularly annuals that are typically "weeds" (00G1) (82A1) (93B3) (94B5) (86J2).

Living crusts of lichens, mosses, algae and cyanobacteria increase soil stability, enhance soil fertility, increase plant-nutrient content, often enhance water infiltration and water-holding capacity, and contribute to mycorrhizial colonization ((88H1), (96L1) in Ref. (99G1)). Cyanobacteria in these soil crusts also fix atmospheric nitrogen ((93E1) in (99G1)) and may be the main source of Nitrogen input into desert- and semi-desert ecosystems (93E1), (99E1) in Ref. (99G2).

There is evidence that intact microbiotic crusts reduce, or prohibit, weed establishment by preventing weed-seed germination ((42M1), (87H1), (86E1), (89M1) in Ref. (99G1)).

More than 100 scientific studies demonstrate the importance of microbiotic crusts in arid ecosystems (97B3).

In numerous studies, grazing has been correlated with the loss of microbiotic cover (94F2) (81J1) (82A2) (87J2).

In steppe environments, where they are so critical to the function of the entire ecosystem, microbiotic crusts normally require 60-100 years to re-establish once they have been destroyed (Claude Treanor, Keating Highway Allotment #2108 Allotment Evaluation (2/6/87). Contact Vale Oregon District, B.L.M.).

The ecosystem component perhaps most critical to healthy rangelands, and the one most disturbed by livestock, is microbiotic crust. There is a broad consensus among botanists and range scientists that these fragile, living covers of the soil surface play a vital role in arid and semiarid rangeland ecosystems ((93S1), (88H1), (94W1), (94K1) in (97B3)).

The most important role of microbiotic crusts is considered to be:

• Stabilized soil surfaces and improved soil fertility;
• Increased herbaceous productivity,
• Reduced weed invasions,
• Fixes nitrogen from the air, and
• Increased plant nutrient content (97B3).

Go to this Chapter's Table of Contents Go to top of Section [C] (Productivity Degradation in Riparian Zones) Go to top of Section [D] (Rangeland Degradation Data) Go to top of Section [E] (Degradation Data Related to Microbiotic Crusts)

After 7-10 years of beef cattle grazing, the effects of overgrazing and torrential rains turn the nutrient-poor soils typical of tropical rainforests into eroded wasteland (Ref. 8 of (83N1)).

Stocking on newly cleared tropical rainforest land is typically 100 AU/ km² during Year 1, and 14-20 AU/ km² during Years 5-10 (83N1).

Forest-derived pasture in the Amazon Basin is productive for fewer than 10 years because of the onset of soil infertility (90W1).

Conversion to pasture of up to 430,000 km² of Amazon rainforest over the past three decades caused rapid decline of productivity and land abandonment after 4-8 years of use (Ref. 43 of Ref. (95D2)).

More than 60% of Mexico's original tropical rainforest has been destroyed -- largely to create cattle pasture (p. 355 of (91J1)).

Since 1960, over 40% of Central America's tropical rainforest has been converted to cattle grazing (p. 356 of (91J1)).

About 50% of Central America is now cattle pasture. Two thirds of Central America's arable land was devoted to cattle production around 1990 (p. 356 of Ref. (91J1)). Trends suggest that this fraction is significantly greater today.

Since 1970, farmers and ranchers have converted more than 200,000 km² of Latin America's moist tropical forest to cattle pasture (91D1). (These converted tropical pastures last 5-10 years before they must be abandoned for 20-30 years to restore soil fertility (91D1).)

As beef production increases in Central America, per-capita beef consumption declines. In Costa Rica, where 71% of all new farmland is beef-cattle pasture, beef production doubled during 1959-72, but per-capita beef consumption in Costa Rica fell from 30 lb. to under 19 lb./ year. Similar data exist for Honduras (83N1).

About 60% of the productive territory in Mexico is pastureland, producing meat for a population, 50% of whom never eat meat. To support the cattle industry, a growing number of Mexico's farmers have switched from food-grains to feed-grains. During the late 1970s, this trend cost Mexico its self-sufficiency in food production. In 1996 Mexico imported a third of its food, primarily from the US (97R1).

Go to this Chapter's Table of Contents ~ Go to top of Section [C] (Productivity Degradation in Riparian Zones) ~ Go to top of Section [D] (Rangeland Degradation Data) ~ Go to top of Section [E] (Degradation Related to Microbiotic Crusts) ~ Go to top of Section [F] (Grazing Lands in Tropical Rainforests) ~

About 40% of all US farm produce, including grain, is fed to livestock (p. 364 of (91J1)).

In 1964, half of all beef cows in the US were on feedlots of fewer than 50 animals. By 1996, nearly 90% of direct cattle feeding occurred on feedlots of 1000 head or more, with 300 feedlots averaging 16,000-20,000 head and nearly 100 feedlots contain in excess of 30,000 head (at any one time) (03A1). (Feedlot- and CAFO livestock consume mainly grain whereas cattle (ruminants) in mixed agriculture feed largely on grass.)

Ruminants plus pigs and poultry also eat feed and fodder raised on 25% of the world's 14.7 million km² of croplands (91D1).

Nearly 90% of the water taken out of streams in the Colorado River basin is used for irrigation to grow hay and other crops for livestock, according to a 1982 Living Wilderness article (90W3).

Livestock production accounts for more than 70% of water consumed in the 11 western US states. In nearly half of the west (generally the most arid portions) in an average year, 70% or more of all surface water is taken, mostly for livestock production (p. 215 of (91J1)).

94% of California's interior broad-leaf woodlands have been significantly damaged or destroyed, largely by livestock (p. 53 of (91J1)).

Lake Chad (Africa) has shrunk to 20% of its size around 1970, mostly due to livestock-caused desertification and to livestock production practices (p. 362 of (91J1)).

Data below are from a Worldwatch Press Briefing on Global Trends in Meat Consumption (7/12/98)

• 36% of the world's grain went (in 1997) to feed livestock and poultry.
• In the developing world, the share of grain fed to livestock has tripled since 1950 to 21% in 1997.
• In the industrial world nearly 70% of grain (produced) was fed to livestock in 1997.
• During 1960-97, the share of Chinese grain going to feed livestock increased from 8 to 26%.
• During 1960-97, the share of Mexican grain going to feed livestock increased from 5 to 45%.
• During 1960-97, the share of Egyptian grain going to feed livestock increased from 3 to 31%.
• During 1960-97, the share of Thailand grain going to feed livestock increased from 1 to 30%.

Some 660 million tonnes/ year (35% of world cereal consumption) are being used as animal feed (03A1).

Industrial nations feed nearly 70% of their grain to livestock (98H2).

Go to this Chapter's Table of Contents ~ Go to top of Section [C] (Productivity Degradation in Riparian Zones) ~ Go to top of Section [D] (Rangeland Degradation Data) ~ Go to top of Section [E] (Degradation Data Related to Microbiotic Crusts) ~ Go to top of Section [F] (Rangelands in Tropical Rainforests) ~

Cultivation is expanding into rangeland that receives precipitation at 30-50 cm./ year. (Good grazing land is becoming poor cropland with high risks of wind erosion and severe drought (85D1).) Since 1700, a steady reduction has occurred in the extent of the world's grazing lands. Over the past few centuries, tens of thousands of km² of the world's great natural grasslands have been converted to croplands. More intensive mixed farming has pushed ranchers into drier regions containing poorer vegetation and soils, i.e. into the margins (Ref. 44 of (84R1)). (Precipitation of 50 cm./ year is considered the minimum for dryland croplands. Less precipitation typically results in large amounts of wind erosion. Rangelands typically have very low soil organic matter contents (perhaps 0.5% carbon content), meaning low productivity, low erosion resistance and numerous other problems. (See Chapter 1 Section [B5].) Huge areas of Latin American tropical rainforest are being converted to grazing lands, so the total area of the world's grazing lands may not be decreasing. What is happening is that good-quality grazing lands are being converted into low-quality croplands, and good-quality tropical rainforests are being converted into low-quality grazing lands.

Rangelands in Iran that were once forest land total 100,000 km² (6.1%) (74S1).

More than 2/3 of the 70 million acres (283,000 km²) of US forests cleared during 1967-75 were converted to grazing land (p. 231 of (91J1)).

Conversions of Original Grasslands ((00W1), p. 123)

Go to this Chapter's Table of Contents ~ Go to top of Section [C] (Productivity Degradation in Riparian Zones) ~ Go to top of Section [D] (Rangeland Degradation Data) ~ Go to top of Section [E] (Degradation Related to Microbiotic Crusts) ~ Go to top of Section [F] (Grazing Lands in Tropical Rainforests) ~ Go to top of Section [G] (Consumption of non-grass resources by Livestock) ~ Go to top of Section [H] (Shifting Land-Use Patterns)

Section [I] ~ DESERT EXPANSION ~[I1]~ Global, [I2]~ North America, [I3]~ Eastern Asia, [I4]~ Central Asia, [I5]~ Southern Asia, [I6]~ Africa, [I7]~ Europe, [I8]~ Latin America,

"Desertification," the process by which productive dryland becomes wasteland, now affects 26 million km² (just over 60%) of the world's rangeland area (98H1).

Climatic data indicate that more than a third of the Earth's land area is desert or semi-desert. Data on soil and vegetation indicate that 43% of the Earth's land surface is desert or semi-desert. The difference is accounted for by the estimated extent of man-made desert -- 9.1 million km² (81S1).

The earth's desertified dryland area totals 36 million km² (70% of global dryland area) (95D2). 26 million km² of these desertified lands exhibit no soil degradation but have reduced crop yields, reduced amounts of livestock forage and reduced inventories of woody biomass for use as fuel and building material (Ref. 20 of (95D2)).

During the past 50 years, mankind has lost an estimated 1 million km² to deserts (20,000 km²/ year) (76O1). (Presumably this is just the "productive dryland." Adding in abandonment of croplands, abandonment of irrigated lands due to salinization etc., and urbanization of cropland and grassland brings the total annual loss to something on the order of 50,000 km²/ year.)

Worldwide, over 23,000 square miles (60,000 km²)/ year becomes desert (Seattle-PI-Com Desertification, 11/23/99). (This seems out of line with other estimates. Perhaps it includes salination losses and urbanization losses.)

The global area of land with adequate water that has been degraded to near-desert conditions is larger than all of Brazil. The process claims 50-70,000 km²/ year (77B1). 60,000 km² of new desert are formed annually by land mismanagement (from data compiled by WorldWatch Institute from various sources) (88B1).

In the 70-year period, 1882-1952, deserts and wastelands increased from 9.4% to 23.3% of the Earth's total terrestrial area (Ehrlich and Ehrlich (1972)) (82O1). (The wording suggests total land area (148 million km²), but it may be based on ice-free land area (130 million km²).)

Ref. (76S1) quotes Reid A. Bryson -- "14 million acres (57,000 km²) of (the world's) productive land are being lost yearly to desert encroachment".

Globally, desertification claims 60,000 km²/ year. An additional 200,000 km² become too debilitated to support profitable farming and grazing (89P1) (89P2). (This might not include urbanization losses. See the review of global literature on cropland and soils degradation (07S2) for estimates of this.)

About 27,200 km² of North America have undergone "very severe" desertification. About 910,000 km² within the US have experienced severe, or very severe, desertification (81S3). (Obsolete data: for historical reference only)

Approximately 464 million acres (1.88 million km²) of US rangeland have undergone some degree of desertification (83D1) (94F2).

Baja California, San Benito Islands (Mexico), and California's San Clemente Island have been converted to wastelands by goats (p. 357 of Ref. (91J1)).

In the US, 225 million acres (911,000 km²) (the size of the 13 original states) are in a state of severe desertification, and another equally large area is in danger of severe desertification (87H1).

Dregne estimates 225 million acres (911,000 km²) of land in the US have experienced "severe" or "very severe" desertification (10% of the US land mass). The area threatened by "severe" desertification is almost twice as large (Ref. 10 of (81S1)).

About 2.8 million km² (36.8%) of North America's arid land area have undergone "severe" desertification; 27,200 km² have undergone "very severe" desertification (Ref. 9 of Ref. (81S1)) (81S3). (Obsolete data: of historical significance only)

On 338,000 acres (1370 km²) of San Joaquin Basin range lands, an inter-agency study found that forage vegetation was so badly over-grazed that it could not revegetate -- it had undergone desertification (81S1) (Ref. 98 of Ref. (81S2)).

On 4/18/01, scientists at the National Oceanic and Atmospheric Administration (NOAA), reported that a huge dust storm from northern China had reached the US "blanketing areas from Canada to Arizona with a layer of dust." They reported that along the foothills of the Rockies the dust from China obscured the mountains. On 3/10/01, The People's Daily reported that the season's first dust storm-one of the earliest on record-had hit Beijing. These dust storms, coupled with those of 2000, were among the worst in memory, signaling widespread deterioration of rangeland and cropland in China's northwest (01B2). These huge dust plumes routinely travel hundreds of miles to populous cities in northeastern China, including Beijing, obscuring the sun, reducing visibility, slowing traffic, and closing airports. Reports of residents in eastern cities caulking windows with old rags to keep out the dust are reminiscent of the US dust bowl of the 1930s. Eastward moving winds often carry soil from China's northwest to North Korea, South Korea, and Japan, countries that regularly complain about dust clouds that both filter out the sunlight and cover everything with dust (01B2). (Continued below)

In addition to local pressures on resources, a decision in Beijing in 1994 to require that all cropland used for construction be offset by land reclaimed elsewhere. This policy has helped create the ecological disasters (dust storms) that are now unfolding. In an article in Land Use Policy, Chinese geographers Hong Yang and Xiubein Li describe the environmental effects of this offset policy. The fast-growing coastal provinces, such as Guandong, Shandong, Xheijiang, and Jiangsu, which are losing cropland to urban expansion and industrial construction, are paying other provinces to plow new land to offset their losses. This provided an initial economic windfall for provinces in the northwest, such as Inner Mongolia (which led the way with a 22% cropland expansion), Gansu, Qinghai, Ningxia, and Xinjiang (01B2).

In Seoul, South Korea, for the third consecutive year, huge clouds of dust have blown in from China's deserts 750 miles away. Consequently, Seoul's residents have suffered breathing problems, school closures, cancelled domestic flights, workplace absenteeism, and dipping retail sales. 70 micrograms of dust/ m³ of air is normal for Seoul, but a recently a record measurement of 2,070 micrograms was reported. The dust is a result of the rapid desertification in China and a prolonged drought affecting China and other parts of Northeast Asia. Tokyo has also seen an unusually dusty spring. Particles of the airborne sand now travel 7,000 miles to Portland, Ore., and San Francisco, by riding the jet stream (" China's Growing Deserts Are Suffocating Korea", New York Times (4/12/02)).

From the mid-1990s to 2000, 1374 square miles (3559 km²) of China have turned into desert each year (vs. 840 square miles (2180 km²) per year in the 1980s, and 624 square miles (1616 km²)/ year during the 1970s (04H1).

China has lost 36,000 square miles (93,240 km²) of land to desert since the 1950s (04H1).

28% of China's land mass has been overtaken by desert, with 18% being decimated by effects of overgrazing and deforestation (China Daily reports (1/31/02)).

Spreading deserts are also displacing people. In China, where the Gobi Desert is growing by 10,400 km² a year, the refugee stream is swelling. Chinese scientists report that there are now desert refugees in three provinces -- Inner Mongolia, Ningxia, and Gansu. An Asian Development Bank preliminary assessment of desertification in Gansu Province has identified 4000 villages that face abandonment (04B1)).

In China's Ganzu province 4000 villages are facing being submerged by drifting sands. The Earth Policy Institute believes that, throughout China, tens of millions of people may be forced off their land, dwarfing the migrations of "Okies" from America's dust bowl (03L1).

Between 1994-99, China's Environmental Protection Agency reports, the Gobi Desert expanded by 20,240 square miles (52,400 km²), to within 150 miles of Beijing. New areas of desert are erupting all over China. Desertification is affecting 40% of China's land. Partly as a result, harvests, which had more than quadrupled between 1950-1998, have fallen sharply, even as China's population and appetite grow (03L1).

From 1950-1975 China lost an average of 1560 km² of land to desert each year. Between 1975-87, this climbed to 2100 km²/ year. From then until 2000, it jumped to 3600 km² of land going to desert annually. Over the last half-century, 24,000 villages in northern and western China have been entirely or partly abandoned as a result of being overrun by drifting sand (06B1).

In the New York Times, Beijing Bureau Chief Erik Eckholm writes that "the rising sands are part of a new desert forming on the eastern edge of the Quinghai-Tibet Plateau, a legendary stretch once known for grass reaching as high as a horse's belly and home for centuries to ethnic Tibetan herders." Official estimates show 900 square miles (2330 km²) of land on the eastern edge of the Quinghai-Tibet Plateau going to desert each year. An area several times as large is suffering a decline in productivity as it is degraded by overuse (01B2).

A 2001 survey conducted by China's State Forestry Administration says 28% of China's land mass has been overtaken by desert, with 18% being decimated by effects of overgrazing and deforestation (China Daily reports (1/31/02)).

China loses 1200 km²/ year of farm- and pasture land to drifting sand dunes (86W1). (Losses to urbanization are several times larger.) (See the Soils and Croplands Degradation Review (07S2)).

China has launched an emergency program to fight desertification after a large number (12) of deadly dust storms in northern China in early 2000. Xinhua said the program aimed to check the rapid expansion of 3 deserts in Inner Mongolia, including one 180 km. from the capital (South China Morning Post (5/24/00)).

In northern China over 900 square miles (2330 km²/ year) of land turn into desert, due mainly to excessive grazing and logging (Daily Grist (7/31/00)).

China's old deserts are advancing and new deserts are forming. Desert expansion has accelerated with each successive decade since 1950. China's Environmental Protection Agency reports that the Gobi Desert expanded by 52,400 km² during 1994-99 (10,500 km²/ year). The advancing Gobi Desert is now within 150 miles (246 km.) of Beijing (03B1).

Over-plowing and overgrazing in China are converging to create a dust bowl of historic dimensions. With little vegetation remaining in parts of northern and western China, the strong winds of late winter and early spring can remove millions of tons of topsoil in a single day. On 4/12/02, for instance, 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. Koreans have come to dread the arrival of what they now call "the fifth season" -- the dust storms of late winter and early spring. Japan also suffers from dust storms originating in China (03B1).

A report by a US embassy official in May 2001 after a visit to Xilingol Prefecture in Inner Mongolia (Nei Mongol) notes that although 97% of the region is officially classified as grasslands, a third of the terrain now appears to be desert. The report says the prefecture's livestock population climbed from 2 million as recently as 1977 to 18 million in 2000. A Chinese scientist doing grassland research in the prefecture says that if recent desertification trends continue, Xilingol Prefecture will be uninhabitable in 15 years. Satellite images show two deserts in north-central China expanding and merging to form a single, larger desert overlapping Inner Mongolia and Gansu provinces. To the west in China's Xinjiang Province, two even larger deserts -- Taklimakan and Kumtag -- are also heading for a merger (03B1).

Millions of rural Chinese may be uprooted. Expanding deserts are driving villagers from their homes in Gansu, Inner Mongolia, and Ningxia provinces. An Asian Development Bank assessment of desertification in Gansu Province reports that 4,000 villages risk being overrun by drifting sands. The US Dust Bowl of the 1930s forced some 2.5 million "Okies" to leave their land, many of them heading from Oklahoma, Texas, and Kansas to California. But the dust bowl forming in China is much larger, and during the 1930s the US population was only 150 million -- compared with 1.3 billion in China today. Whereas the US "Okie" migration was measured in the millions, China's may eventually measure in the tens of millions (03B1).

Beijing is trying to arrest the spread of deserts by encouraging pastoralists to reduce their flocks of sheep and goats by 40%. The chairman of China's Environment and Resources Committee of the National People's Congress, estimates that remediation of land in the areas, where technically feasible, would cost $28.3 billion (03B1).

Dust storms have been recorded in China for at least 2,700 years, but they are now increasing in size and number. The Chinese Meteorological Agency says there were 5 major storms in China in the whole of the 1950s. This rose to 23 in the 1990s. But the first two years of this decade have almost equaled this figure already, with 20 (03L1). They have even occasionally crossed the Pacific: one in April 2001 covered the west of North America from Canada to Arizona with dust (03L1).

Growing livestock populations are changing 900 square miles (2331 km²) of China to desert/ year (" Dust Bowl Threatening China's Future", earth-policy.org (4/18/01)).

Deserts now cover 2.62 million km², or 27% of China (South China Morning Post (5/24/00)).

About 25% of China's land mass is composed of deserts (06P1).

Expanding deserts swallow about 4000 km² of land in China (06P1).

China's EPA said that soon 40% of China could turn into scrubland, creating massive social, economic and ecological challenges (06P1).

China has 350 million cattle, sheep, goats, and yaks in 2005, vs. 100 million in 1960 (06P1).

Desertification is costing China $7.7 billion/ year (06P1).

About 4000 Chinese villages have been entirely swallowed by encroaching desert (06P1).

Expanding deserts swallow about 4000 km² of land (per year) in China (06P1)

The Gobi Desert in central China has expanded by about 65,000 km² since 1994, and its sands are now within 100 miles of Beijing (06P1).

About 4000 km² of China's arable land have been lost to urban sprawl over the past decade (06P1).

In China's western province of Xinjiang, the Tarim River, which began to run dry in 1972 following construction of a reservoir in its middle, has almost totally disappeared (06P1).

The FAO contends (03N1) that countries such as China and India are making major efforts to restore degraded land in arid areas (97S2). There are widespread efforts to restore saline soils and other degraded soils that have gone out of production. In the view of some analysts, restored lands could total 2-3 million km² by 2025 (03N1) On the negative side, at least in the medium term, are the expansion or intensification of cropping in semi-arid areas and further losses from salinization. This author has encountered a few reports of degraded land restoration projects in China. E.g. China is planting 26 million acres (105,000 km²), 10% of its grain-growing area, with trees. But many die because the soil is already too thin (03L1). China's land restoration projects have generally been failures. The continued expansion of deserts due to deforestation and overgrazing in China would suggest that any restoration successes would be overwhelmed by desert expansion and other land degradation processes. E.g. Over-grazing affects 510,000 km² (23% of China's total grassland). Biomass productivity on China's 2.22 million km² of grasslands has dropped 30-50% since the 1960's (89C1). Between 1994 and 1999, China's Environmental Protection Agency reports, the Gobi Desert expanded by 52,400 km². New areas of desert are erupting all over China. Desertification is affecting 40% of China's 9.6 million km² of land, i.e. 3.8 million km². Partly as a result, harvests, which more than quadrupled between 1950-1998, have fallen sharply, even as China's population and appetite grow (03L1).

Desertification extent in Russia (as of 1993) (03Z1).

The indicated extent of desertification in Russia is in line with previous studies (Stolbovoi and Fischer (1999)). According to the latest estimates, the area (of Russia) affected by desertification is currently (2003) about 1 million km² (03Z1). (This is surprising - an increase in desertified area of about 650,000 km² just during the period 1993-2003. This figure should probably be regarded with some suspicion due to its large size - although Russ