Dust To Dust.

Deserts are growing around the world and one may be coming soon to a neighbourhood near you

The Sahara Desert has an area of about 9,065,000 square kilometres, and covers parts of ten countries in northern Africa. It's the largest desert in the world, and it's getting larger. Overgrazing and removal of trees for fuelwood have destroyed groundcover in the semiarid Sahel region to the south of the Sahara. Rainfall runoff and the wind have carried off the fertile topsoils, and left dry, barren wastelands. As a result, by 1973, after several years of drought, the Sahara had advanced southward up to 100 kilometres; it's estimated that, during that year, 100,000 people died of starvation and disease as a direct result. Severe drought and famine hit the Sahel again in 1983-85, and government reforestation programs were unable to stop the spreading sands.

The gradual spread of desert land is a process known as desertification, and it's a worldwide problem. As populations grow and place increasing demands on the semi-arid lands around deserts, they can irreversibly damage the plants that concentrate moisture and hold the soil together, allowing deserts to encroach on arable land. A 1984 report of a desertification study made for the United Nations stated that 35% of the earth's land surface was at least threatened by such processes.

While Canada doesn't have any true deserts, it does have regions with desert-like features, such as the sandy expanse south of Lake Athabasca. Some areas in the Canadian Arctic, which don't have vegetation and are exposed to strong winds, also have a desert-like appearance. The driest parts of the Prairies, and the most southerly parts of the Fraser, Thompson, Nicola, Similkameen, Okanagan, and Kootenay river valleys have precipitation as low as 250 mm to 300 mm a year. In these regions the vegetation is of the semi-arid type, such as sagebrush.

In March 2001, Alberta farmers were bracing themselves for another extreme drought. This followed a dry winter in cattle country, at the end of a dry year. Ranchers are afraid they may have to sell off some of their herds because there won't be enough grass to feed them all, or enough drinking water. The province has had the driest winter since the 1930s with less than 40% of average precipitation in most areas. To a lesser extent, southwest Saskatchewan and northeast British Columbia have been hit too. All told, 40,000 cattle farms, six million head of cattle, 10 million hectares of pastureland, and more than 11 million hectares of cropland have been affected by the parched conditions. If Environment Canada's prediction is correct, a wet, cool spring could ease the problem. In addition, agricultural experts say farming methods have improved enough in the intervening years that a repeat of the situation created by the 1930s drought is unlikely.

But, some observers think deserts may form more of our future landscapes.

Many of the predictions of global warming point to one probable outcome -- a huge swath of Canada's southern Prairie is going to become a desert. This area is already semi-arid and irrigation is needed in many places in order to coax a decent crop out of the land. Scientists predict annual precipitation is going to drop to between five and 25 centimetres; that's not enough to support crops.

So, if the predictions are correct, the Canadian Prairies are drying up, and the country's breadbasket is literally blowing away. Increasingly unstable weather patterns could turn it into a wasteland. Elaine Wheaton, a climatologist with the Saskatchewan Research Council in Saskatoon, was quoted in a newspaper article in October 2000 as saying that average winter temperatures across the agricultural band of the Canadian Prairies will rise six or seven degrees within a few decades. In the summer, they might be three to four degrees higher. This all adds up to the possibility of new warm-weather crop diseases and insects, flooding, and massive soil erosion by wind and water.

Some scientists say global warming could result in future droughts far worse than those of the 1930s. Others see a rosier future with warmer weather and more precipitation, which will give Prairie farmers two growing seasons, one in November as well as in summer months. Farmers also will turn to crops that require less water, planting corn rather than wheat for example. In addition, optimists say warmer weather could turn northern land that's too cold for crops now into farmland.

But extreme weather - such as ice storms (Quebec in 1998) and tornadoes (Alberta in the summer of 2000) - is still a concern because it's becoming more routine. Extreme conditions that used to hit only once a century are much more frequent: in the 1990s, there were more weather catastrophes than in any other recorded decade.

Some of the world's biggest disasters have been the result of fuzzy thinking.

A glaring example of society's folly is the Aral Sea, which ought to be called the Aral Puddle these days. Back in the days of Soviet central planning someone in Moscow came up with the idea of turning the dry land around the Aral Sea into the world's biggest cotton growing region. The Amu and Syr rivers, which fed the Aral Sea, were diverted to irrigate the semi-arid steppe that was planted with cotton bushes. The Aral Sea, once the world's fourth-largest inland body of water, had supported a thriving fishing industry. Within three decades, by the late 1980s, the Sea was too shallow to sail and the fish had been destroyed by pesticides and a growing concentration of salt. With its water supply cut off, the Sea receded hundreds of kilometres. A smaller sea meant an even greater demand for water: farmers needed more water to flush the salt dust from crops. Summers became hotter and dryer. Irrigation water carrying salt, pesticides, fertilizers, and defoliants from the soil began to seep into drinking water. By 1991, the shrinking of the Aral Sea was causing sand and rain storms that devastated farms 500 kilometres away. Experts estimate that the Sea will vanish by 2010. The cotton-growing land is now poisoned with salt and the local population is facing starvation.

Lake Chad in North Africa is another body of water that's almost disappeared: it has shrunk by more than 90% since the 1960s, research suggests that irrigation is a major cause. Fish stocks are now threatened as well as crops. The problem continues to get worse because for more than three decades there have been few of the monsoon rains that previously filled the region's rivers. That, in turn, has led to more irrigation projects. Lake Chad has shrunk from an area of 25,100 square kilometres in 1963 to about 1,500 square kilometres today.

But, humans are nothing if not resourceful when faced with a challenge.

In some dry parts of the world, residents are coming up with some intriguing ways to increase their water supply. In one of the driest parts of northern Chile, for example, they're literally trapping water in nets. In the mountain village of Caleta Chungungo only about 700 mm of rain falls a year. Life was becoming difficult and bringing in truckloads of water was expensive. So, some Chilean environmental groups got together with Canadian researchers and international funding agencies to capture water from Chamanchaca, a low-lying cloud that passes over the village most nights. The project involves setting up 86 nylonmesh-covered panels - about the size of advertising billboards - on a mountainside to tap the cloud as it passes. Droplets of water from the cloud condense on the mesh, eventually fall through the holes, and are channelled into reservoirs. The water is filtered and chlorinated before consumption. Some days a single panel can capture 700 litres of water, and the monthly "catch" is about 300,000 litres. That's equal to about 30 truckloads, at one-fifth of the cost.

FACT FILE

According to Jay Malcolm at the University of Toronto's forestry department, the current shift in temperature is taking place 10 times faster than the retreat of the last ice age.

FACT FILE

In climatological terms, a change in temperature of even half a degree is significant: average temperatures during the last ice age were just five degrees lower than they are now.

SUGGESTED ACTIVITIES:

1. David Runnalls at the International Institute Jar Sustainable Development in Winnipeg says that strategies and policies to adapt to the coming climate changes are urgently needed for the world's food supply as well as Jar Canada's sake. He says scientists and politicians need to share ideas, but they aren't doing so. Contact Agriculture Canada to find out if anything is being done to prepare us Jar what some see as an uncertain future. Invite a climatologist to speak to the class.

2. By April 2001, much of New Zealand was in the midst of a drought, after one of the country's driest summers on record. Rainfall in the capital of Wellington Jar the previous three months was the lowest since record keeping began in 1862, and some of the country's rivers had dried up. A government meteorologist said the pattern was typical for the end of a La Nina ocean-cooling pattern. For farmers, the dryness, plus more sunshine than usual, has withered their pastures. Find out more about La Nina as an example of a natural cause of dramatic climate change.

Websites

Desertification Information
Network - http://www.wcmc.
org.uk/dynamic/desert/

Did You Know (Deserts)
http://www.didyouknow.com/
deserts.htm

Eden Foundation (Sahel)
http://www.eden-foundation.
org/project/desertif.html

United Nations - http://www.
unccd.int/main.php

RELATED ARTICLE: MILKING CAMELS

In a part of world too dry for cows to survive, a veterinary expert sees camels as a good source of milk. An Israeli professor, Reuven Yagil, at Ben-Gurion University Medical School in Beersheba, has worked with camels for 30 years. He says their milk could be a lifesaver in areas where children are dying of hunger.

In 2000, Prof. Yagil managed a herd of 40 camels at a small experimental farm on the border between Jordan and Israel in the Negev desert. He says they are very economical milk producers because they eat farm refuse, including salt bushes, cacti leaves, or peanut hay.

Camel milk keeps up to nine days if refrigerated, and up to two years if frozen. In addition to alleviating hunger, it is also used in Arab society to boost the immune system.

Prof. Yagil is spreading the word and both China and Kenya are planning to pick up the idea.

RELATED ARTICLE: THE WORST OF TIMES

The oldest farmers in Saskatchewan can still remember the Dirty Thirties, when people abandoned their farms and had to accept government relief to survive. Dust storms through the 1930s were so intense that farmers couldn't see their fields from the roads. Lakes dried up. Disease wiped out even the hardiest wheat. By 1938, plagues of grasshoppers devoured much of what was left. The period, which affected one quarter of the country's arable land, was Canada's worst drought. It started in 1929 and continued until midsummer of 1937. Severe wind erosion of the topsoil made the effects of the drought even worse. As a result, many farms were abandoned and farm families moved elsewhere.

The drought of the 1930s led to the creation of federal and provincial government agencies to develop and manage drought-alleviation programs, including the Prairie Farm Rehabilitation Administration (PFRA). The PFRA gave prairie farmers financial and technical assistance to help build water-storage reservoirs such as dugouts and small dams. New tillage machines were developed, which disturbed the soil as little as possible, thereby decreasing soil susceptibility to erosion. Government agencies in Alberta, Saskatchewan, and Manitoba also developed programs to help farmers.

RELATED ARTICLE: DEFINITION

Desert - term applied to regions of the earth that are characterized by less than 254 mm of annual rainfall, an evaporation rate that exceeds precipitation, and, in most cases, a high average temperature. Because of a lack of moisture in the soil and low humidity in the atmosphere, most of the sunlight penetrates to the ground.

Daytime temperatures can reach 55 [degrees] C in the shade. At night the desert floor radiates heat back to the atmosphere, and the temperature can drop to near freezing.