Collapse: How Societies Choose to Fail or Succeed (74 page)

Australians say that they want less rather than more immigration. In the
long run it is doubtful that Australia can even support its present popula
tion: the best estimate of a population sustainable at the present standard of living is 8 million people, less than half of the present population.

Driving inland from the state capital of Adelaide in South Australia, the
only Australian state to have originated as a self-supporting colony because
of its soils' decent productivity (high by Australian standards, modest by standards outside Australia), I saw in this prime farmland of Australia one
ruin after another of abandoned farms. I was able to visit one of those ruins
preserved as a tourist attraction: Kanyaka, a large manor developed as a
sheep farm at considerable expense by English nobility in the 1850s, only to
fail in 1869, to become abandoned, and never to be reoccupied. Much of
that area of inland South Australia was developed for sheep farming during
the wet years of the 1850s and early 1860s, when the land was covered with
grass and looked lush. With droughts beginning in 1864, the overgrazed landscape became littered with the bodies of dead sheep, and those sheep
farms were abandoned. That disaster stimulated the government to send the
surveyor-general G. W. Goyder to identify how far inland from the coast the
area with rainfall sufficiently reliable to justify farming extended. He de
fined a line that became known as the Goyder Line, north of which the like
lihood of drought made attempts at farming imprudent. Unfortunately, a
series of wet years in the 1870s encouraged the government to resell at high
prices the abandoned sheep farms of the 1860s, as small overcapitalized
wheat farms. Towns sprang up beyond the Goyder Line, railways expanded, and those wheat farms in turn succeeded for a few years of abnormally high
rainfall until they too failed and became consolidated into larger holdings
that reverted to being large sheep farms in the late 1870s. With the return of
drought, many of those sheep farms subsequently failed once again, and those that still survive today cannot support themselves based on sheep:
their farmer/owners require second jobs, tourism, or outside investments to
make a living.

There have been more or less similar histories in most other food-
producing areas of Australia. What made so many initially profitable food-producing properties become less profitable? The reason is Australia's
number-one environmental problem, land degradation, resulting from a set
of nine types of damaging environmental impacts: clearance of native vege
tation, overgrazing by sheep, rabbits, soil nutrient exhaustion, soil erosion,

man-made droughts, weeds, misguided government policies, and saliniza-
tion. All of these damaging phenomena operate elsewhere in the world, in
some cases with even greater individual impact than in Australia. Briefly,
these impacts are as follows:

I mentioned above that the Australian government formerly required
tenants leasing government land to clear native vegetation. While that re
quirement has now been dropped, Australia still clears more native vegetation per year than any other First World country, and its clearance rates are exceeded in the world only by Brazil, Indonesia, the Congo, and Bolivia.
Most of Australia's current land clearance is going on in the state of
Queensland for the purpose of creating pasture land for beef cattle. The
Queensland government has announced that it will phase out large-scale clearing
—but not until 2006. The resulting damage to Australia includes
land degradation through dryland salinization and soil erosion, impair
ment of water quality by runoff of salt and sediment, loss of agricultural
productivity and land values, and damage to the Great Barrier Reef (see be
low). Rotting and burning of the bulldozed vegetation contribute to Aus
tralia's annual greenhouse gas admissions a gas quantity approximately equal to the country's total motor vehicle emissions.

A second major cause of land degradation is overstocking of sheep in numbers that graze down the vegetation faster than it can regrow. In some
areas such as in parts of the Murchison District of Western Australia, over
grazing was ruinous and irreversible because it led to loss of the soil. Today,
now that overgrazing's effects are recognized, the Australian government
imposes
maximum
stocking rates for sheep: i.e., farmers are
forbidden
to
stock more than a certain number of sheep per acre on leased land. For
merly, however, the government imposed
minimum
stocking rates: farmers
were
obliged
to stock a certain minimum number of sheep per acre as a con
dition of holding the lease. When sheep stocking rates first became well documented in the late 19th century, they were three times higher than the rates considered sustainable today, and before documentation began in the
1890s sheep stocking rates were apparently up to 10 times higher than sus
tainable rates. That is, the first settlers mined the standing crop of grass, rather than treating it as a potentially renewable resource. Just as was true
for land clearance, the government thus required farmers to damage the
land and cancelled leases of farmers who failed to damage the land.

Three other causes of land degradation have already been mentioned.
Rabbits remove vegetation as do sheep, cost farmers by reducing the pas
turage available to sheep and cattle, and also cost farmers through the

expense of the bulldozers, dynamite, fences, and virus release measures that
farms adopt to control rabbit populations. Nutrient exhaustion of soils
often develops within the first few years of agriculture, because of the low
initial nutrient content of Australian soils. Erosion of topsoil by water and
wind increases after its cover of vegetation has been thinned or cleared. The
resulting runoff of soil via rivers into the sea, by making coastal waters turbid, is now damaging and killing the Great Barrier Reef, one of Australia's
major tourist attractions (not to mention its biological value in its own right and as a nursery of fish).

The term "man-made drought" refers to a form of land degradation sec
ondary to land clearance, sheep overgrazing, and rabbits. When the cover of
vegetation is removed by any of these means, land that the vegetation had
previously shaded now becomes directly exposed to the sun, thereby mak
ing the soil hotter and drier. That is, the secondary effects creating hot and
dry soil conditions impede plant growth in much the same way as does a
natural drought.

Weeds, discussed in Chapter 1 in connection with Montana, are defined
as plants of low value to farmers, either because they are less palatable (or
totally unpalatable) to sheep and cattle than preferred pasture plants, or because they compete with useful crops. Some weeds are plant species unin
tentionally introduced from overseas; about 15% were intentionally but misguidedly introduced for use in agriculture; one-third escaped into the wild from gardens where they had been intentionally introduced as orna
mentals; and other weed species are Australian native plants. Because graz
ing animals prefer to eat certain plants, the action of grazing animals tends to increase the abundance of weeds and to convert pasture cover to plant species that are less utilized or unutilizable (in some cases, poisonous to
animals). Weeds vary in the ease with which they can be combatted: some
weed species are easy to remove and to replace with palatable species or
crops, but other weed species are very expensive or prohibitively difficult to
eliminate once they have become established.

About 3,000 plant species are considered weeds in Australia today and
cause economic losses of about $2 billion per year. One of the worst is Mi
mosa, which threatens an especially valuable area, the Kakadu National
Park and the World Heritage Area. It is prickly, grows up to 20 feet tall, and
produces so many seeds that it can double the area that it covers within a year. Even worse is rubber vine, introduced in the 1870s as an ornamental shrub from Madagascar to make Queensland mining towns prettier. It es
caped to become a plant monster of a type depicted in science fiction:

besides being poisonous to livestock, smothering other vegetation, and
growing into impenetrable thickets, it drops pods that disperse far by float
ing down rivers, and that eventually pop open to release 300 seeds carried far by the wind. The seeds within one pod suffice to cover two-and-a-half
acres with new rubber vines.

To the misguided government policies of land clearance and sheep over
stocking previously mentioned may be added the policies of the govern
ment's Wheat Board. It has tended to make rosy predictions of higher world
wheat prices, thereby encouraging farmers to incur debt for capital invest
ments in machinery to plant wheat on land marginal for wheat growing.
Many farmers then discovered, to their misfortune after investing much
money, that the land could support wheat for only a few years, and that
wheat prices dropped.

The remaining cause of land degradation in Australia, salinization, is the
most complex and requires the most explanation. I mentioned previously
that large areas of Australia contain much salt in the soil, as legacies of salty sea breezes, former ocean basins, or dried-out lakes. While a few plants can
tolerate salty soils, most plants, including almost all of our crops, cannot. If the salt below the root zone just stayed there, it wouldn't be a problem. But
two processes can bring it up towards the surface and start causing prob
lems: irrigation salinization and dryland salinization.

Irrigation salinization has the potential for arising in dry areas where
rainfall is too low or too unreliable for agriculture, and where irrigation is necessary instead, as in parts of southeastern Australia. If a farmer "drip-
irrigates," i.e., installs a small irrigation water fixture at the base of each fruit
tree or crop row and allows just enough water to drip out as the tree's or
crop's roots can absorb, then little water is wasted, and there is no problem. But if the farmer instead follows the commoner practice of "broadcast irrigation," i.e., flooding the land or else using a sprinkler to distribute the wa
ter over a large area, then the ground gets saturated with more water than
the roots can absorb. The unabsorbed excess water percolates down to that
deeper layer of salty soil, thereby establishing a continuous column of wet
ted soil through which the deep-lying salt can percolate either up to the
shallow root zone and the surface, where it will inhibit or prevent growth of
plants other than salt-tolerant species, or else down to the groundwater table and from there into a river. In that sense, the water problems of Aus
tralia, which we think of as (and which is) a dry continent, are not problems of too little water but of too much water: water is still sufficiently cheap and
available to permit its use in some areas for broadcast irrigation. More

exactly, parts of Australia have enough water to permit broadcast irrigation,
but not enough water to flush out all the resulting mobilized salt. In principle, problems of irrigation salinization can be partly mitigated by going to the expense of installing drip irrigation instead of broadcast irrigation.

The other process responsible for salinization, besides irrigation salin
ization, is dryland salinization, potentially operating in areas where rainfall suffices for agriculture. That's true especially in the areas of Western Aus
tralia and parts of South Australia with reliable (or formerly reliable) winter
rains. As long as ground in such areas is still covered with its natural vegeta
tion, which is present all year, the plants' roots take up most of the rain
falling, and little rainwater remains to percolate down through the soil to
establish contact with the deeper salt layers. But suppose a farmer clears the
natural vegetation and replaces it with crops, which are planted seasonally
and then harvested, leaving the ground bare for part of the year. Rain soak
ing the ground when it is bare does percolate down to the deep-lying salt,
permitting it to diffuse up to the surface. Unlike irrigation salinization, dryland salinization is difficult, expensive, or essentially impossible to reverse
once the natural vegetation has been cleared.

One can think of salt mobilized by either irrigation or dryland saliniza
tion into soil water as like a salty underground river, which in some parts of
Australia has salt concentrations three times those of the ocean. That un
derground river flows downhill just as does a normal above-ground river,
but much more slowly. Eventually, it may seep out into a downhill depres
sion, creating hypersaline ponds that I saw in South Australia. If a farmer on
a hilltop adopts bad land management practices that cause his land to be
come salinized, the salt may slowly flow through the ground to the land of
farms lying downhill, even if those farms are well managed. In Australia
there is no mechanism whereby the owner of a downhill farm that has been
thus ruined can collect compensation from the owner of an uphill farm re
sponsible for his ruin. Some of the underground river doesn't emerge in
downhill depressions but instead flows down into above-ground rivers, in
cluding Australia's largest river system, the Murray/Darling.

Salinization inflicts heavy financial losses on the Australian economy, in three ways. First, it is rendering much farmland, including some of the most valuable land in Australia, less productive or useless to grow crops and raise
livestock. Second, some of the salt is carried into city drinking water supplies. For instance, the Murray/Darling River provides between 40% and 90% of the drinking water of Adelaide, South Australia's capital, but the
river's rising salt levels could eventually make it unsuitable for human con-