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Agriculture to Flourish in the Sahara?

Agriculture to Flourish in the Sahara?


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Norwegian environmentalist takes on green initiative for barren lands, and apparently succeeds.

In a country that imports 93 percent of its food, it’s no surprise that there are initiatives being taken to improve its agriculture. With temperatures that reach up to 120 degrees and roughly three inches of rain per year, Qatar is a primal example of a country that deals with climate change in a progressive way.

Joakim Hauge is the CEO of the Sahara Forest Project, an environmental business that aims to improve and strengthen agriculture in dry climates while remaining accessible enough that local resources fuel the salt-water based greenhouses that they implement. PBS reports, “The design is meant to mimic a natural eco-system, where the waste product from one component provides the food or fuel for another.” Through these systems, saltwater is pumped through small sustainable greenhouses to cool the air, while a mirror, reflecting sunlight, and carbon dioxide pumped in from a nearby factory, aid in the growth and nourishment of plants. The pools of saltwater that provide the stream for cooling also grow algae in them, allowing for the potential of biofuel development.

While still in the testing phase of these greenhouses, they prove themselves to be working well and are successful at redistributing appropriate nutrients to the soil. The technologies can be implemented anywhere that has a dry climate and access to saltwater — opening up agricultural possibilities for many countries that struggle to grow food on their own.


Nomadic Herding: An Ecological System of Agriculture

Nomadic herding is an ecological or near ecological system of agri­culture. It is carried on mainly to produce food for the family and to fulfill the needs of clothing, shelter and recreation. It is the simplest form of pastoralism.

The nomadic herders are dependent on sheep, cattle, goats, camels, horses and reindeers for their livelihood. Herds composition varies from one region to another, but throughout the dry belt sheep and goats are the most common animals and cattle are the least common as they do not like hot and arid climates.

The length of stay of the nomads at one place and the direction of their movement are governed by the availability of water and natural forage. The nomad’s and herder’s house is generally a tent which can be transported easily. The arid and semiarid areas of the world, from the shores of At­lantic in Africa to the steppes of Mongolia, have been occupied by the pastoral nomads for the last more than 3000 years (Grigg, 1978).

Nomadic herding, at present, is mainly concentrated in Saharan Af­rica (Mauritania, Mali, Niger, Chad, Sudan, Libya, Algeria), the southwestern and central parts of Asia, the northern parts of the Scandinavian countries (Norway, Sweden, Finland) and northern Canada. All these areas are sparsely populated. Owing to the non­-availability of water, these areas are unsuitable for the cultivation of crop but the people are utilizing these ecosystems for rearing or graz­ing of livestock.

The nomads graze their herds on native grasses and migrate from one place to another in search of grass and water. In the poor grazing areas sheep and goats constitute the mains herds horses, mules and donkeys are common herds in the semiarid and temperate grasslands camels and yaks are important in the deserts and plateaux respec­tively while reindeer is important in the Arctic region.

At the deple­tion of pastures, the herders have to move their herds to new pas­tures. Thus, after every few days, they have to migrate with their herds. With the change of season these nomads migrate to long dis­tances in the plains and from low lands to high lands.

The size and composition of herds vary a great deal amongst pas­toral nomads. Livestock are generally owned by families, and fami­lies grouped in tribes, but the migratory unit is generally smaller than the tribe. In the Middle East, each migratory unit consists of five or six families. Each family requires about 25-60 goats and sheep or 10- 25 camels for minimum subsistence.

The food of nomads is mostly of animal origin, i.e., milk, cheese, curd, butter and meat. Despite the importance of animals as a source from which most of the material wants are supplied, herds in the ab­sence of controlled breeding, tend to be of a low grade with some ex­ceptions in the case of horses and camels.

Though the nomadic herd­ing areas are well scattered in the different semiarid parts of the world, they can be classified into the following three regions:

(ii) Southwest Asia and Northern Africa, and

(i) Nomadic Herders of the Central Asia:

The nomadic herding areas of Central Asia include Mongolia, Tibet, Sinkiang, Turkmenistan, Kazakhstan, Uzbekistan and the Kirghizia steppes. These are the traditional lands of nomads. The Kazaks, Kir­ghiz and Mongols are among the principal pastoral nomads. These nomads in search of fodder and water migrate to the foothills, high valleys, plateaux, broad basins and high mountains of Central Asia.

In Central Asia, owing to the scarcity and uncertainty of rains, culti­vation of crops with success cannot be done, and facilities of artifi­cial irrigation are generally not available. Therefore, cultivation of crops is not profitable. Moreover, in Central Asia, the climate, soil and natural grasses have a great diversity. As a result, the life of no­madic herders of Central Asia is attached to herds which flourish well in the grasslands of the region.

(ii) Nomadic Herders of Southwest Asia and North Africa:

The nomadic herding region of Southwest Asia and North Africa consists of Iraq, Iran, Syria, Jordan, Saudi Arabia, UAE, Plateau of Anatolia (Turkey), and Sudan, semiarid fringes of the Sahara desert and the high lands of eastern Africa (Fig. 5.2). In this region, the rainfall is scanty and in many parts the average annual rainfall is less than 25 cm (10 inches). In the semiarid climatic conditions only grasses of small size grow as the major natural vegetation.

The scarcity of rainfall leads to paucity of pastures. These condi­tions are best suited for sheep and goats as they can survive even un­der the drought conditions and poor pastures for some time. This re­gion, therefore, is one of the most important goats and sheep rearing areas of the world. Angora goats, famous for their silky wool, known as mohair, are especially numerous in Anatolia (Turkey).

The camel is also more important here than anywhere else as it can live without water and fodder in the hot deserts for some days and can endure hardships. In the highlands of east-central Africa the Masai herder tribe grazes their sheep and goats in the short grass pastures of the sa­vannas in the valleys in winters and they migrate to the rich pastures of tall grasses of the high plateaux and mountains in the summers.

(iii) Nomadic Herders of Tundra:

On the southern margins of Tundra, there are certain nomadic herd­ers, e.g., Lapps, Yakuts and Eskimos. These herders have adjusted themselves to the food supply of reindeer. In the northern parts of Norway, Sweden, Russia and Finland such herders constitute a sig­nificant part of the population.

During the short summer they live on the grassy mountains and in autumn they migrate along with their herds in coniferous areas of the south in order to meet the fodder re­quirements of their herds and to protect them from the freezing conditions of the Tundra climate.

Many a times they cross the interna­tional boundaries to get fodder and to avoid starvation. For the Lapps of Norway, Sweden, Finland and Russia, special provisions of inter­national law have been made which allow them to migrate from one country to another at the time of fodder and food shortage.

In the present century a large change has occurred in the life style of nomadic herders. Nomads have suffered owing to reduction of their grazing areas as livestock ranching has moved into drier re­gions, and pressure has been put on many communities to adopt sed­entary way of life, notably in the socialist countries where collective and state farms have encroached the natural grasslands of the no­mads.

In the semiarid areas sedentarization has been started, and the respective governments are planning to bring more nomadic grazing areas under agriculture. In general, the population of nomadic herd­ers has been decreasing and areas dominated by them in the past have been shrinking. Moreover, it appears that true nomadism is likely to survive in few pockets of small isolated areas.


The people creating an oasis with seawater

An almost infinite supply of an under-used resource could turn unfarmable land into lush fields and solve the world’s food crisis – at least that’s the hope. A decade on, have the projects worked?

W hile the coronavirus pandemic has highlighted the weakness of supply chains, for many people the fragility of our food networks is nothing new. Rising populations in water-stressed areas of the world increase the demand for food in the places it is hardest to grow, and the climate crisis is only making matters worse. The lack of freshwater is a serious threat to the survival of many people worldwide and drought caused by climate change compounds the issue.

The World Health Organization predicts that by 2025, half of the global population will be living in water-stressed areas, where the demand for clean, usable water surpasses the amount available.

But what if freshwater isn’t the answer? What if there was a way to feed the world without adding to the strain on our water supply? What if, in fact, there was an almost infinite source of water we could farm with?

Some innovators say the solution to saving our most precious resource might be right in front of us. “It’s wrong to say that water is a finite resource because it is an infinite resource we just don't manage it very well,” says Charlie Paton, the UK-based founder and director of Seawater Greenhouse.

While the planet’s fresh water may be limited, the Seawater Greenhouse project harnesses the power of two things we do have an ample supply of – seawater and sunlight – to grow food in the middle of the desert.

Paton and his team have established successful seawater greenhouses in arid, sun-baked coastal locations like Oman, the UAE and Australia over the past decade, and most recently, Somaliland. Through an innovative method of desalination, these completely solar-powered greenhouse operations use saltwater – piped directly from the sea into wells – to create ideal growing conditions.

Some of the greenhouses are impressive operations – steel frame and glass buildings set in fields of solar arrays, while others are little more than canvas sheets wrapped around timber. But it’s what’s inside that counts. Rows of fruit or vegetables impossible to grow in a desert juicy cucumbers, plump tomatoes and brilliant red raspberries defy the elements.

A close up of a pad shows the large surface area over which seawater evaporates (Credit: Sahara Forest Project Foundation)

The projects garnered international acclaim and in 2017, rising like a mirage out of the scorched earth 15km from the Red Sea near the Gulf of Aqaba in Jordan, came the Sahara Forest Project, a competitor seawater greenhouse site the size of four football fields.

Much like the landscape in Somaliland and parts of Australia, Jordan is a perfect candidate for seawater greenhouse technology: it has a hot, arid climate – the country is number five on the World Resource Institute’s list of most water-stressed countries in the world – and it is close to a saltwater source.

“Let's make use of what there is enough of on the planet, which is saltwater, sunlight, and deserts,” says Kjetil Stake, managing director of the project. “Let's use those resources to produce what we need more of, which is sustainably-produced food, freshwater and clean energy. Eighty percent of the freshwater that is being used today is used in agriculture. When we reach [a population of] 10 billion people in 2050, how are we going to produce food in a way which does not harm the planet?”

How to grow food from seawater

Inside the greenhouses, a cool, humid oasis of plants and vegetables flourishes. Fleshy fruits, salad leaves and velvety aubergines would all normally require large volumes of water to grow. But the beauty of a seawater greenhouse is that water can be reused efficiently.

As plants grow, they evaporate water through their leaves and flowers in a process called transpiration. Plants lose more water rapidly in hot, dry conditions. “It's the same thing as hanging a sheet out on the line to dry,” says Paton. “If it's a grey, cloudy day in the UK, it won't dry [but] if it's in the middle of Saudi Arabia, it'll be dry in 10 minutes.”

So, to grow crops in the desert, he explains, you need to recreate something similar to the soggy UK climate inside the greenhouse. The cooler, moist microclimate means plants require less freshwater and less irrigation, thereby reducing water usage and overall costs.

Seawater greenhouses make this possible with adapted pad and fan technology. Fans (or wind, in some cases) push air through water-soaked “pads” – layers of corrugated card hung vertically – producing a vapour that adds moisture to the greenhouse and drops the temperature by around 15C.

While traditional pad and fan systems use freshwater, seawater greenhouses make use of saltwater. The effect is the same. As the water is pushed through the pad, the salt is separated from the freshwater and this high-salinity water, called brine, is used to cool the greenhouse.

Paton says that brine is more effective than freshwater for this “evaporative cooling” purpose. Brine has both a higher boiling point and lower freezing point than pure water, which means it works better as a coolant. Heat energy is absorbed by the brine as water evaporates from it further, helping to cool the air around the pads. As it condenses, the desalinated fresh water irrigates the crops, revegetates the surrounding landscape outside the greenhouse and provides clean drinking water.

A misty plant oasis grows in the Jordanian desert (Credit: Sahara Forest Project Foundation)

And unlike traditional desalination methods, which can be costly and dump large amounts of salty brine back into the sea, disrupting fragile ecosystems, the seawater greenhouse model is eco-friendly. Any leftover salty brine that isn’t used in the cooling cycle is evaporated and made into salt. Paton says his aim is to achieve “zero discharge from desalination”.

Looking back to grow a better future

While the seawater greenhouse is a fairly novel idea, it brings together elements of technology and design that already existed – some of which have roots in the Middle East and north Africa. “Arabic architecture uses fountains and water cascading down surface walls and pools because they knew that evaporating water would cool the place down,” says Paton. “There are lots of old palaces in Iran that use sophisticated evaporative cooling systems to air condition themselves, so it's a very old technology.”

Residual water vapour creates an oasis effect that extends past the greenhouse and, by using desalinated water to revegetate the surrounding area, the Sahara Forest Project hopes to make a lasting change in the landscape, restoring today’s deserts into the forests they once were. “In my lifetime I’ve seen many parts of the world flipped from being reasonably wet areas with vegetation to being completely arid,” says Paton. Worldwide deforestation not only wreaks havoc on ecosystems but drastically reduces the number of trees that pull CO2 from the air, which offsets our carbon emissions. “We want to green the desert,” says Stake. “The larger areas we manage to green, the more carbon we would store in the soil.”

Revegetation could help mend the water cycle by facilitating the natural process of evaporation, eventually returning the water to the earth as rain. Increasing deforestation and urban development to meet the needs of a rising population have created a rift in this process. “Every time you cover a field in concrete or asphalt, you've reduced that component of evaporation,” explains Paton. “So, as society grows and develops, it does so without much concern for the water cycle.”

Another untapped benefit of seawater greenhouses is the ability to ‘mine’ elements like lithium, cobalt and magnesium from the brine

The theory is extremely attractive take a resource we have plenty of and turn it into something useful, then take the by-product and put that to good use, too. How many farming practices are truly win-win-win like this?

Wind power has been used to cool homes in the Middle East for centuries (Credit: Alamy)

Plants flourished outside the greenhouses in Jordan after only a couple months, says Stake. Paton’s Seawater Greenhouse projects have seen similar success with revegetation. He says after two years the land around the site in Oman began to flourish. Though not all sites are as far ahead. Some do still appear to be lonely greenhouses standing in the desert – not quite the lush oases the projects aspire to be.

In addition to the environmental benefits seawater greenhouses offer, the technology could provide a major economic boost, green jobs, as well as the potential for agricultural self-sufficiency, allowing countries to rely less on imports, or in the case of places like Somaliland, food aid.

We are very climate-resilient and supermarkets like that – Paton

Seawater greenhouses offer the possibility of stable, climate-resistant agricultural production in places like Australia where a climate of extremes can make farming difficult. Seawater Greenhouse established a large commercial project with Sundrop Farms in Port Augusta, Australia that now produces 15% of Australia’s tomatoes. “We are self-sufficient in making our own freshwater and cooling and air conditioning,” Paton says. “We are very climate-resilient – and supermarkets like that.”

The Sahara Forest Project sells some of their vegetables at local markets in Jordan (though minimally so as not to cause friction with local growers), and the company also landed a major deal with Italian Costa and AIDA cruise ships, where their seawater veggies are incorporated into the on-board menus. This partnership is temporarily on hold while travel is restricted because of Covid-19 but is expected to resume post-pandemic. Plans are also in the works to export vegetables to Norway.

Paton says there’s potential for seawater greenhouses to play an additional role in providing more sustainable options for tourism growth. In Saudi Arabia, for instance, a massive tourism project is underway which will require enormous amounts of desalinated water. “If they pursue the ‘business as usual’ approach, the increased salinity from brine waste in the Gulf and Red Sea will have a seriously detrimental effect on all marine life,” says Paton. “If instead, they use [the brine] for evaporative cooling, the greening up and cooling down potential is colossal. If they also use renewable energy to drive the process, the carbon capture potential is even more colossal,” says Paton.

Life has returned to the desert around one of the Seawater Greenhouse projects (Credit: Seawater Greenhouse)

Another untapped benefit of seawater greenhouses is the ability to “mine” elements like lithium, cobalt and magnesium from the brine. These can then be sold for use in other industries. “There are fantastic volumes of lithium in seawater but it's very diluted,” Paton says. “But because we evaporate seawater, we end up concentrating the brine, which makes it much easier to extract valuable things from it.”

Mining minerals from brine on salt flats that have high concentrations of metals like lithium and magnesium has been a commercial endeavour around the world for years, but Paton is now to test extracting lithium from desalinated-seawater brine in Somaliland, where he will be partnering with Salt-Mine in the coming months.

Challenging the competition

Like many green industries, seawater greenhouses have faced challenges. At the outset, Paton says they were perceived as a threat to existing agricultural policies and partnerships. The technological success of an early pilot project in the Canary Islands led to pushback from stakeholders concerned about undermining the monopoly European growers benefited from under the Common Agricultural Policy. Seawater greenhouses could enable growers in places like Eritrea, for example – where an NGO had plans for a seawater greenhouse project – to compete with Europeans. So funding was pulled and the project shut down.

Local culture also factors into planning project sites. In Somaliland, for instance, Paton says that farming isn’t part of the culture, which can be a barrier to local engagement and investment. “[In Somaliland], agriculture tends to be looked down on as being hard work, only fit for the very poor. while camel and livestock ownership is the primary aspiration and indicator of wealth,” explains Paton. “Under such circumstances, a large, commercial horticultural operation [like we established in Australia] would be beset by land ownership conflicts, clan friction, mistrust of outsiders, and attempts to take over by one clan or another.” In order to establish successful seawater greenhouses in Somaliland, Paton and the team focused on implementing smaller, family-run projects.

Ruba Al Zubi, advisor to the president for science policy at Jordan’s Royal Scientific Society, says that an understanding of local attitudes toward agriculture is critical. “Technology, innovation and cultural transformation need to be addressed adequately,” she says. “[In Jordan, we need] a cultural shift in how the agriculture sector is perceived from a socio-economic angle… and communication around agriculture as a key economic sector for Jordan to encourage transformation on a national level.” The Sahara Forest Project has been pivotal in making this happen. “Showing the impact on productivity and socio-economic development is a real marketing tool for the transformation we aspire to and for mobilising efforts and support,” says Al Zubi.

Projects like this can also demonstrate the possibilities of a triple bottom line: when done right, Stake says, business can be good for people by creating jobs, good for the planet, and profitable. “We want to be an inspiration for others,” he says, “to show that it is possible to make money doing good business.”

Like the implementation of any new green industry, scaling this technology will likely mean overcoming obstacles – cultural, economic, and otherwise. But in the deserts of Jordan, Somaliland, and elsewhere, the plump, technicolour plants and vegetables grown in seawater greenhouses are blooming beacons of hope.

This article is part of Follow the Food, a series investigating how agriculture is responding to environmental challenges. Follow the Food traces emerging answers to these problems – both high-tech and low-tech, local and global – from farmers, growers and researchers across six continents.


The Sahara Desert

Blanketing much of the northern third of the African Continent, or some 3.5 million square miles, the Sahara Desert, the largest desert in the world, extends eastward from the Atlantic Ocean some 3,000 miles to the Nile River and the Red Sea, and southward from the Atlas Mountains of Morocco and the Mediterranean shores more than 1,000 miles to the savannah called the Sahel. More than 16 times the size of France, the Sahara Desert blankets nearly all of Mauritania, Western Sahara, Algeria, Libya, Egypt and Niger the southern half of Tunisia and the northern parts of Mali, Chad and Sudan.

The Sahara Desert impacts almost all of the countries of northern Africa.

Landscape

The Sahara's topographical features, said "The Living Africa," include not only the iconic sand dune fields, but also arid mountains, plateaus, sand- and gravel-covered plains, shallow basins and large oasis depressions. Its highest point is Chad's Mount Koussi (an extinct volcanic crater that rises 11,204 feet above sea level at the peak), and its lowest, Egypt's Qattera Depression (an oasis depression that lies 436 feet below sea level at the deepest point).

The Sahara's fabled dune fields, which cover only about 15 percent of the entire desert's surface, lie primarily in the north central region, in the countries of Algeria and Libya. Most sand dunes -- mounds and ridges of sand sculpted by wind and gravity -- have a windward or "backslope" surface and a leeward or "slipface" surface. Prevailing winds drive sand up the backslope until it reaches a crest and then collapses under the pull of gravity, cascading down the slipface. The wind may leave rippled surfaces in its wake.

Saharan dunes as seen from the eastern edge of Morocco.

The dunes take on varied and complex forms. A few examples include:

  • Crescent dunes, which have arms or "horns" that point downwind and embrace the slip face. These dunes form under winds that have blown from the same direction for an extended period.
  • Linear dunes, which have long, straight or slightly sinuous forms, that may extend for miles. They develop under winds that blow from either of two directions.
  • Transverse dunes, which have sharply crested, roughly saber-shaped forms that lie parallel and may reach to nearly a thousand feet in height and extend for over a hundred miles in length. They form in alignment with a prevailing wind that has changed direction for a prolonged period and redistributed the sands of earlier dunes.
  • Star dunes, which have central pyramidal mounds with three or more radiating arms, each with a backslope and a slipface. The star dunes form under winds that blow from several directions.
  • Dome dunes, which have circular- or oval-shaped mounds, which, surprisingly, have no backslope or slipface. Comparatively rare, they tend to form at the upwind edges of dune fields.

The dunes, with their various forms, raise many questions about the dynamics of their formation.


Sahara's most famous features are the ergs, or sand dune seas, most of it is really hamada, or rocky plateau.

Water

The Sahara has only two permanent rivers and a handful of lakes, but it has substantial underground reservoirs, or aquifers.

Its permanent rivers are the Nile and the Niger. The Nile rises in central Africa, south of the Sahara, and flows northward through Sudan and Egypt and empties into the Mediterranean. The Niger rises in western Africa, southwest of the Sahara, and flows northeastward into Mali and the desert then turns southeastward, through Nigeria, and empties into the Gulf of Guinea.

The Sahara has some 20 or more lakes, but only one with potable water--the expansive but shallow Lake Chad, a continually expanding and shrinking body of water that lies in the country of Chad, at the southernmost edge of the Sahara. Other lakes hold a briny stew of undrinkable water.

The Sahara's aquifers often lie just below the surface of intermittent drainages, called "wadis," which rise in mountain ranges and empty onto the desert floor. The aquifers sometimes discharge some of their waters to the surface at locations called "oases," which are normally found in the lower points of surface depressions.

Shot of Sahara Desert made possible by NASA's MODIS instrument (Moderate Resolution Imaging Spectroradiometer). Data collected from June through Sept 2001

Climate

The Sahara has one of the world's most severe climates. Typically, the Sahara landscape experiences extremely limited to virtually no rainfall, powerful and capricious winds and wide temperature ranges.

Across the desert, the annual average rainfall equals no more than a few inches or less, much less in many locations. In some areas, no rain at all may fall over several years. Then, several inches may fall in a torrential downpour. Then, no rain at all may fall for several more years.

The prevailing wind, which blows from the northeast toward the equator throughout the year, accounts for the desert's aridness. As the wind moves southwestward, the air warms, dissipating moisture that might otherwise be released as rainfall. Locally, hot winds often lift sand and dust particles from the desert floor, spinning them upward through cooler air as dust devils or propelling them southwestward as fierce and blinding dust storms.

In the summer, daytime air temperatures across the Sahara often soar to well over 100 degrees Fahrenheit, with the hottest air temperature meteorologists have ever recorded -- 136 degrees -- occurring at Azizia, Libya, on September 13, 1922. Under the clear skies, the temperature may fall 40 degrees or more during an evening. In the winter, freezing temperatures may occur in the northern Sahara, and milder temperatures, across the southern Sahara. Snow may fall occasionally in some of the higher mountain ranges and rarely, on the desert floor.

One of the most storied and unforgiving lands in the world, the Sahara -- the Arabic word for "desert" -- evokes a poignant sense of time and nature's power, of antiquity and legend, of wonder and mystery. It has been the setting for some of the most pivotal chapters in Western history.


How A Hudson Valley Startup Helps Farmers Flourish And Workers Eat Their Veggies

When Donna Williams, a former investment banker, got laid off from a food industry startup after the 2008 financial crisis, she figured it was time to start her own company. "I started to fish around for some ideas, and I was now very educated in the food space," she told me.

In the meantime, in 2010, Williams landed a consulting project for the Greene County Industrial Development Agency in New York's Hudson Valley to assess the feasibility of starting an incubator program for new agricultural ventures. As Williams dug into the problems facing the region's many small farmers, she soon saw an entrepreneurial opportunity of her own.

"What I walked away with is that there is a huge demand for local food and a lot of people that want to start farming. But in my opinion there wasn't a scalable distribution system for small farms," said Williams, 52.

To remedy the problem, she founded Field Goods, a farm-to-office subscription food delivery service and employee wellness program that buys its produce from local farms. Tapping her own savings and securing a $25,000 micro-enterprise grant from Greene County, she launched in 2011 in Athens, NY, with a handful of farmers and delivered the produce herself.

Field Goods has come a long way since then. The company now delivers local farm produce to about 3,500 subscribers at 510 workplaces and community centers in eastern New York State and Fairfield County, CT. (They're hoping to add clients in New Jersey and Massachusetts soon.) Williams works with a network of 80 farmers in the region, and employs 33 full and part-time workers at her 18,000 square-foot cold storage warehouse. While she declined to disclose her revenue for competitive reasons, she said sales have been doubling every year.

Williams isn't the only one to search for ways to link local food producers and consumers. Regional food hubs, for-profit and nonprofit entities that aggregate and distribute food from local farms, are springing up all over the country, many in the past five years, reports Modern Farmer, which dubbed Field Goods "a CSA on steroids." The author was referring to Community Supported Agriculture programs, (CSAs) which tend to serve relatively small numbers of people, who generally have to pay upfront at the beginning of the growing season.

A typical CSA works really well in either urban areas, where people pick up their order within walking distance of home, or in rural areas, where they typically drive right up to the farm, Williams learned.

"But the reality for the rest of us folks is that we're not going to a farm," said Williams. So, she decided to "suburbanize" the CSA concept and made it a whole lot easier for people to eat their veggies.

Currently, subscribers pay by the week -- $15 for the smallest bag up to $30 for the largest -- and if they want to put their deliveries on hold, they can do so. They can also add on locally produced specialty items to their weekly delivery, such as fresh-baked bread, cooking oils, butter and cheese. Produce for the week of March 7 include a stir-fry vegetable mix, Bosc pears, a bunch of carrots, frozen broccoli and cauliflower and fresh garlic. Typically, there are about seven or eight different items in the bags each week.

Williams made a critical decision about her business model early on: she decided to approach local employers and marketed Field Goods to corporate HR departments as a "wellness benefit."

"Whats the root cause of so many health problems? It's diet," said Williams. "Field Goods keeps them out of the grocery store. You lose when you go to the grocery store. You're gonna walk out with those cookies."

The first employer to sign on was Albany Medical Center in the state's capital. Later on, she landed baby food maker BeechNut Nutrition Corp., in Amsterdam, NY, Blue Sky Studios in Greenwich, CT, and FujiFilm, with locations in Stamford, CT, and Valhalla, NY. All three of those three private-sector companies signed on for "BEETCamp," a 10-week wellness program where the company subsidizes their employees' weekly Field Goods subscription. Workers also get a newsletter with recipes and nutritional information.

“We have tried dozens of wellness programs and none has come close to the popularity and impact of Field Goods,“ said Carolyn Gordon, director of benefits at Fujifilm Holdings America Corp., in a statement from Field Goods last year announcing the expansion of BEETCamp.

Making HR execs happy and employees healthy is certainly a noble goal, but the business model would fail if Field Goods didn't benefit farmers by solving some critical problems they face as small businesses.

"We pick what goes in the bag, so we can react to what's in the field, if you will. And we don't have to have the perfect pepper. We don't have to put that product on a shelf," Williams tells me. "That's incredibly valuable to farmers because the waste in the field is a lot less."

For example, one of Field Goods' most popular items is the "fingerling" sweet potato. In truth, there's no such vegetable -- these are sweet potatoes that haven't matured fully and wouldn't make the cut in a giant supermarket. "People love them but they're really ugly and funky-looking," she said.

Field Goods is also providing a market for quirkier specialty crops, like eschalions, a cross between a shallot and an onion, and kale sprouts, a brussel sprouts-kale hybrid.

Adam Hainer, who runs Juniper Hill, a 40-acre certified organic farm nestled in the Adirondack Mountains in Wadhams, NY, told me that working with Field Goods has enabled him to scale more quickly than he could have by just supplying his CSA customers with produce. His business used to taper off after the busy summer season, but now Field Goods provides a market well into the fall and winter for the farm's root vegetables.

"When we started working with Donna we were in our fourth year and were struggling to find a large enough market to scale up our business. Along came Donna and we had the opportunity to go from 10 acres in production to 40 over the next couple years," Hainer wrote in an email. "She knows we can't compete with the huge farms from a price perspective but understands the need of the many farms she supports to their own communities and New York State as a whole."

For her part, Williams isn't looking to get rich or to make a quick exit, but, true to her MBA roots (she went to Columbia University) she does want to expand the reach of Field Goods. She's presently evaluating the Boston market as a base for reaching out to neighboring states.

"We’re getting more and more people hearing about us and calling us," she said. "A lot of small companies and regular people who say they heard about us and ask 'can you come to our company.' And we say, 'sure.' It's, in some ways, kind of culty. We have a really loyal customer base and people really love their Field Goods."


12 Best Organic Wines for Every Occassion

There's a lot of confusion over organic wines, and for good reason. Grapes can be certified organic, as can entire vineyards and wineries. There are even a few discrepancies that allow 90% organic wines to bear the label. With USDA standards as our guide, we gathered a list of the finest wines that are as real as it gets.

This white wine bursts with the fresh taste of pineapple and citrus. It's like a tropical vacation in a glass.

Said to be "robust enough to accompany a fine meal," this Nativa wine is the perfect complement to your Sunday dinner.

Creamy vanilla spices give this fruity white a sweet touch.

You can taste the love and care that goes into this bottle. Parducci, known for its sustainable practices and top-notch varieties, is an expert in spicy reds.

While it isn't certified organic, this bold red wine is completely vegan. Yep, that means no animal products or questionable ingredients.

Blending French and Chilean varietals, this medium body red is both affordable and full of goodness.

This cabernet sauvignon is as real as it gets. It's like eating a bowl of fresh cherries.

Organically grown in Argentina, this layered wine boasts a mix of black raspberry and spice flavors.

Skip the glass and go straight for the goods. The less fuss, the better.

. if you'd rather drink something light and fruity.

Made with certified organic grapes, this pinot noir is just as silky and elegant as it is delicious.

This gorgeous garnet wine just gets better with time &mdash like most wines do. Vanilla, prune and plum notes are behind its sweet taste.


Contents

The Sahara covers large parts of Algeria, Chad, Egypt, Libya, Mali, Mauritania, Morocco, Niger, Western Sahara, Sudan and Tunisia. It covers 9 million square kilometres (3,500,000 sq mi), amounting to 31% of Africa. If all areas with a mean annual precipitation of less than 250 mm were included, the Sahara would be 11 million square kilometres (4,200,000 sq mi). It is one of three distinct physiographic provinces of the African massive physiographic division.

The Sahara is mainly rocky hamada (stone plateaus) ergs (sand seas – large areas covered with sand dunes) form only a minor part, but many of the sand dunes are over 180 metres (590 ft) high. [9] Wind or rare rainfall shape the desert features: sand dunes, dune fields, sand seas, stone plateaus, gravel plains (reg), dry valleys (wadi), dry lakes (oued), and salt flats (shatt or chott). [10] Unusual landforms include the Richat Structure in Mauritania.

Several deeply dissected mountains, many volcanic, rise from the desert, including the Aïr Mountains, Ahaggar Mountains, Saharan Atlas, Tibesti Mountains, Adrar des Iforas, and the Red Sea Hills. The highest peak in the Sahara is Emi Koussi, a shield volcano in the Tibesti range of northern Chad.

The central Sahara is hyperarid, with sparse vegetation. The northern and southern reaches of the desert, along with the highlands, have areas of sparse grassland and desert shrub, with trees and taller shrubs in wadis, where moisture collects. In the central, hyperarid region, there are many subdivisions of the great desert: Tanezrouft, the Ténéré, the Libyan Desert, the Eastern Desert, the Nubian Desert and others. These extremely arid areas often receive no rain for years.

To the north, the Sahara skirts the Mediterranean Sea in Egypt and portions of Libya, but in Cyrenaica and the Maghreb, the Sahara borders the Mediterranean forest, woodland, and scrub eco-regions of northern Africa, all of which have a Mediterranean climate characterized by hot summers and cool and rainy winters. According to the botanical criteria of Frank White [11] and geographer Robert Capot-Rey, [12] [13] the northern limit of the Sahara corresponds to the northern limit of date palm cultivation and the southern limit of the range of esparto, a grass typical of the Mediterranean climate portion of the Maghreb and Iberia. The northern limit also corresponds to the 100 mm (3.9 in) isohyet of annual precipitation. [14]

To the south, the Sahara is bounded by the Sahel, a belt of dry tropical savanna with a summer rainy season that extends across Africa from east to west. The southern limit of the Sahara is indicated botanically by the southern limit of Cornulaca monacantha (a drought-tolerant member of the Chenopodiaceae), or northern limit of Cenchrus biflorus, a grass typical of the Sahel. [12] [13] According to climatic criteria, the southern limit of the Sahara corresponds to the 150 mm (5.9 in) isohyet of annual precipitation (this is a long-term average, since precipitation varies annually). [14]

Important cities located in the Sahara include Nouakchott, the capital of Mauritania Tamanrasset, Ouargla, Béchar, Hassi Messaoud, Ghardaïa, and El Oued in Algeria Timbuktu in Mali Agadez in Niger Ghat in Libya and Faya-Largeau in Chad.

The Sahara is the world's largest low-latitude hot desert. It is located in the horse latitudes under the subtropical ridge, a significant belt of semi-permanent subtropical warm-core high pressure where the air from the upper troposphere usually descends, warming and drying the lower troposphere and preventing cloud formation. [ citation needed ]

The permanent absence of clouds allows unhindered light and thermal radiation. The stability of the atmosphere above the desert prevents any convective overturning, thus making rainfall virtually non-existent. As a consequence, the weather tends to be sunny, dry and stable with a minimal chance of rainfall. Subsiding, diverging, dry air masses associated with subtropical high-pressure systems are extremely unfavorable for the development of convectional showers. The subtropical ridge is the predominant factor that explains the hot desert climate (Köppen climate classification BWh) of this vast region. The descending airflow is the strongest and the most effective over the eastern part of the Great Desert, in the Libyan Desert: this is the sunniest, driest and the most nearly "rainless" place on the planet, rivaling the Atacama Desert, lying in Chile and Peru.

The rainfall inhibition and the dissipation of cloud cover are most accentuated over the eastern section of the Sahara rather than the western. The prevailing air mass lying above the Sahara is the continental tropical (cT) air mass, which is hot and dry. Hot, dry air masses primarily form over the North-African desert from the heating of the vast continental land area, and it affects the whole desert during most of the year. Because of this extreme heating process, a thermal low is usually noticed near the surface, and is the strongest and the most developed during the summertime. The Sahara High represents the eastern continental extension of the Azores High, [ citation needed ] centered over the North Atlantic Ocean. The subsidence of the Sahara High nearly reaches the ground during the coolest part of the year, while it is confined to the upper troposphere during the hottest periods.

The effects of local surface low pressure are extremely limited because upper-level subsidence still continues to block any form of air ascent. Also, to be protected against rain-bearing weather systems by the atmospheric circulation itself, the desert is made even drier by its geographical configuration and location. Indeed, the extreme aridity of the Sahara is not only explained by the subtropical high pressure: the Atlas Mountains of Algeria, Morocco and Tunisia also help to enhance the aridity of the northern part of the desert. These major mountain ranges act as a barrier, causing a strong rain shadow effect on the leeward side by dropping much of the humidity brought by atmospheric disturbances along the polar front which affects the surrounding Mediterranean climates.

The primary source of rain in the Sahara is the Intertropical Convergence Zone, a continuous belt of low-pressure systems near the equator which bring the brief, short and irregular rainy season to the Sahel and southern Sahara. Rainfall in this giant desert has to overcome the physical and atmospheric barriers that normally prevent the production of precipitation. The harsh climate of the Sahara is characterized by: extremely low, unreliable, highly erratic rainfall extremely high sunshine duration values high temperatures year-round negligible rates of relative humidity a significant diurnal temperature variation and extremely high levels of potential evaporation which are the highest recorded worldwide. [15]

Temperature

The sky is usually clear above the desert, and the sunshine duration is extremely high everywhere in the Sahara. Most of the desert has more than 3,600 hours of bright sunshine per year (over 82% of daylight hours), and a wide area in the eastern part has over 4,000 hours of bright sunshine per year (over 91% of daylight hours). The highest values are very close to the theoretical maximum value. A value of 4300 hours (98%) of the time would be [ clarification needed ] recorded in Upper Egypt (Aswan, Luxor) and in the Nubian Desert (Wadi Halfa). [16] The annual average direct solar irradiation is around 2,800 kWh/(m 2 year) in the Great Desert. The Sahara has a huge potential for solar energy production.

The high position of the Sun, the extremely low relative humidity, and the lack of vegetation and rainfall make the Great Desert the hottest large region in the world, and the hottest place on Earth during summer in some spots. The average high temperature exceeds 38 to 40 °C or 100.4 to 104.0 °F during the hottest month nearly everywhere in the desert except at very high altitudes. The world's highest officially recorded average daily high temperature [ clarification needed ] was 47 °C or 116.6 °F in a remote desert town in the Algerian Desert called Bou Bernous, at an elevation of 378 metres (1,240 ft) above sea level, [16] and only Death Valley, California rivals it. [17] Other hot spots in Algeria such as Adrar, Timimoun, In Salah, Ouallene, Aoulef, Reggane with an elevation between 200 and 400 metres (660 and 1,310 ft) above sea level get slightly lower summer average highs, around 46 °C or 114.8 °F during the hottest months of the year. Salah, well known in Algeria for its extreme heat, has average high temperatures of 43.8 °C or 110.8 °F, 46.4 °C or 115.5 °F, 45.5 °C or 113.9 °F and 41.9 °C or 107.4 °F in June, July, August and September respectively. There are even hotter spots in the Sahara, but they are located in extremely remote areas, especially in the Azalai, lying in northern Mali. The major part of the desert experiences around three to five months when the average high strictly [ clarification needed ] exceeds 40 °C or 104 °F while in the southern central part of the desert, there are up to six or seven months when the average high temperature strictly [ clarification needed ] exceeds 40 °C or 104 °F. Some examples of this are Bilma, Niger and Faya-Largeau, Chad. The annual average daily temperature exceeds 20 °C or 68 °F everywhere and can approach 30 °C or 86 °F in the hottest regions year-round. However, most of the desert has a value in excess of 25 °C or 77 °F.

Sand and ground temperatures are even more extreme. During daytime, the sand temperature is extremely high: it can easily reach 80 °C or 176 °F or more. [18] A sand temperature of 83.5 °C (182.3 °F) has been recorded in Port Sudan. [18] Ground temperatures of 72 °C or 161.6 °F have been recorded in the Adrar of Mauritania and a value of 75 °C (167 °F) has been measured in Borkou, northern Chad. [18]

Due to lack of cloud cover and very low humidity, the desert usually has high diurnal temperature variations between days and nights. However, it is a myth that the nights are especially cold after extremely hot days in the Sahara. [ citation needed ] On average, nighttime temperatures tend to be 13–20 °C (23–36 °F) cooler than in the daytime. The smallest variations are found along the coastal regions due to high humidity and are often even lower than a 10 °C or 18 °F difference, while the largest variations are found in inland desert areas where the humidity is the lowest, mainly in the southern Sahara. Still, it is true that winter nights can be cold, as it can drop to the freezing point and even below, especially in high-elevation areas. [ clarification needed ] The frequency of subfreezing winter nights in the Sahara is strongly influenced by the North Atlantic Oscillation (NAO), with warmer winter temperatures during negative NAO events and cooler winters with more frosts when the NAO is positive. [19] This is because the weaker clockwise flow around the eastern side of the subtropical anticyclone during negative NAO winters, although too dry to produce more than negligible precipitation, does reduce the flow of dry, cold air from higher latitudes of Eurasia into the Sahara significantly. [20]

Precipitation

The average annual rainfall ranges from very low in the northern and southern fringes of the desert to nearly non-existent over the central and the eastern part. The thin northern fringe of the desert receives more winter cloudiness and rainfall due to the arrival of low pressure systems over the Mediterranean Sea along the polar front, although very attenuated by the rain shadow effects of the mountains and the annual average rainfall ranges from 100 millimetres (4 in) to 250 millimetres (10 in). For example, Biskra, Algeria, and Ouarzazate, Morocco, are found in this zone. The southern fringe of the desert along the border with the Sahel receives summer cloudiness and rainfall due to the arrival of the Intertropical Convergence Zone from the south and the annual average rainfall ranges from 100 millimetres (4 in) to 250 millimetres (10 in). For example, Timbuktu, Mali and Agadez, Niger are found in this zone. The vast central hyper-arid core of the desert is virtually never affected by northerly or southerly atmospheric disturbances and permanently remains under the influence of the strongest anticyclonic weather regime, and the annual average rainfall can drop to less than 1 millimetre (0.04 in). In fact, most of the Sahara receives less than 20 millimetres (0.8 in). Of the 9,000,000 square kilometres (3,500,000 sq mi) of desert land in the Sahara, an area of about 2,800,000 square kilometres (1,100,000 sq mi) (about 31% of the total area) receives an annual average rainfall amount of 10 millimetres (0.4 in) or less, while some 1,500,000 square kilometres (580,000 sq mi) (about 17% of the total area) receives an average of 5 millimetres (0.2 in) or less. [21] The annual average rainfall is virtually zero over a wide area of some 1,000,000 square kilometres (390,000 sq mi) in the eastern Sahara comprising deserts of: Libya, Egypt and Sudan (Tazirbu, Kufra, Dakhla, Kharga, Farafra, Siwa, Asyut, Sohag, Luxor, Aswan, Abu Simbel, Wadi Halfa) where the long-term mean approximates 0.5 millimetres (0.02 in) per year. [21] Rainfall is very unreliable and erratic in the Sahara as it may vary considerably year by year. In full contrast to the negligible annual rainfall amounts, the annual rates of potential evaporation are extraordinarily high, roughly ranging from 2,500 millimetres (100 in) per year to more than 6,000 millimetres (240 in) per year in the whole desert. [22] Nowhere else on Earth has air been found as dry and evaporative as in the Sahara region. However, at least two instances of snowfall have been recorded in Sahara, in February 1979 and December 2016, both in the town of Ain Sefra. [23]

Desertification and prehistoric climate

One theory for the formation of the Sahara is that the monsoon in Northern Africa was weakened because of glaciation during the Quaternary period, starting two or three million years ago. Another theory is that the monsoon was weakened when the ancient Tethys Sea dried up during the Tortonian period around 7 million years. [24]

The climate of the Sahara has undergone enormous variations between wet and dry over the last few hundred thousand years, [25] believed to be caused by long-term changes in the North African climate cycle that alters the path of the North African Monsoon – usually southward. The cycle is caused by a 41000-year cycle in which the tilt of the earth changes between 22° and 24.5°. [21] At present (2000 ACE), we are in a dry period, but it is expected that the Sahara will become green again in 15000 years (17000 ACE). When the North African monsoon is at its strongest annual precipitation and subsequent vegetation in the Sahara region increase, resulting in conditions commonly referred to as the "green Sahara". For a relatively weak North African monsoon, the opposite is true, with decreased annual precipitation and less vegetation resulting in a phase of the Sahara climate cycle known as the "desert Sahara". [26]

The idea that changes in insolation (solar heating) caused by long-term changes in the Earth's orbit are a controlling factor for the long-term variations in the strength of monsoon patterns across the globe was first suggested by Rudolf Spitaler in the late nineteenth century, [27] The hypothesis was later formally proposed and tested by the meteorologist John Kutzbach in 1981. [28] Kutzbach's ideas about the impacts of insolation on global monsoonal patterns have become widely accepted today as the underlying driver of long-term monsoonal cycles. Kutzbach never formally named his hypothesis and as such it is referred to here as the "Orbital Monsoon Hypothesis" as suggested by Ruddiman in 2001. [27]

During the last glacial period, the Sahara was much larger than it is today, extending south beyond its current boundaries. [29] The end of the glacial period brought more rain to the Sahara, from about 8000 BCE to 6000 BCE, perhaps because of low pressure areas over the collapsing ice sheets to the north. [30] Once the ice sheets were gone, the northern Sahara dried out. In the southern Sahara, the drying trend was initially counteracted by the monsoon, which brought rain further north than it does today. By around 4200 BCE, however, the monsoon retreated south to approximately where it is today, [31] leading to the gradual desertification of the Sahara. [32] The Sahara is now as dry as it was about 13,000 years ago. [25]

Lake Chad is the remnant of a former inland sea, paleolake Mega-Chad, which existed during the African humid period. At its largest extent, sometime before 5000 BC, Lake Mega-Chad was the largest of four Saharan paleolakes, and is estimated to have covered an area of 350,000 km2. [33]

The Sahara pump theory describes this cycle. During periods of a wet or "Green Sahara", the Sahara becomes a savanna grassland and various flora and fauna become more common. Following inter-pluvial arid periods, the Sahara area then reverts to desert conditions and the flora and fauna are forced to retreat northwards to the Atlas Mountains, southwards into West Africa, or eastwards into the Nile Valley. This separates populations of some of the species in areas with different climates, forcing them to adapt, possibly giving rise to allopatric speciation.

It is also proposed that humans accelerated the drying out period from 6,000 to 2,500 BCE by pastoralists overgrazing available grassland. [34]

Evidence for cycles

The growth of speleothems (which requires rainwater) was detected in Hol-Zakh, Ashalim, Even-Sid, Ma'ale-ha-Meyshar, Ktora Cracks, Nagev Tzavoa Cave, and elsewhere, and has allowed tracking of prehistoric rainfall. The Red Sea coastal route was extremely arid before 140 and after 115 kya (thousands of years ago). Slightly wetter conditions appear at 90–87 kya, but it still was just one tenth the rainfall around 125 kya. In the southern Negev Desert speleothems did not grow between 185 and 140 kya (MIS 6), 110–90 (MIS 5.4–5.2), nor after 85 kya nor during most of the interglacial period (MIS 5.1), the glacial period and Holocene. This suggests that the southern Negev was arid-to-hyper-arid in these periods. [35]

During the Last Glacial Maximum (LGM) the Sahara desert was more extensive than it is now with the extent of the tropical forests being greatly reduced, [36] and the lower temperatures reduced the strength of the Hadley Cell. This is a climate cell which causes rising tropical air of the Inter-Tropical Convergence Zone (ITCZ) to bring rain to the tropics, while dry descending air, at about 20 degrees north, flows back to the equator and brings desert conditions to this region. It is associated with high rates of wind-blown mineral dust, and these dust levels are found as expected in marine cores from the north tropical Atlantic. But around 12,500 BCE the amount of dust in the cores in the Bølling/Allerød phase suddenly plummets and shows a period of much wetter conditions in the Sahara, indicating a Dansgaard-Oeschger (DO) event (a sudden warming followed by a slower cooling of the climate). The moister Saharan conditions had begun about 12,500 BCE, with the extension of the ITCZ northward in the northern hemisphere summer, bringing moist wet conditions and a savanna climate to the Sahara, which (apart from a short dry spell associated with the Younger Dryas) peaked during the Holocene thermal maximum climatic phase at 4000 BCE when mid-latitude temperatures seem to have been between 2 and 3 degrees warmer than in the recent past. Analysis of Nile River deposited sediments in the delta also shows this period had a higher proportion of sediments coming from the Blue Nile, suggesting higher rainfall also in the Ethiopian Highlands. This was caused principally by a stronger monsoonal circulation throughout the sub-tropical regions, affecting India, Arabia and the Sahara. [ citation needed ] Lake Victoria only recently became the source of the White Nile and dried out almost completely around 15 kya. [37]

The sudden subsequent movement of the ITCZ southwards with a Heinrich event (a sudden cooling followed by a slower warming), linked to changes with the El Niño-Southern Oscillation cycle, led to a rapid drying out of the Saharan and Arabian regions, which quickly became desert. This is linked to a marked decline in the scale of the Nile floods between 2700 and 2100 BCE. [38]

The Sahara comprises several distinct ecoregions. With their variations in temperature, rainfall, elevation, and soil, these regions harbor distinct communities of plants and animals.

The Atlantic coastal desert is a narrow strip along the Atlantic coast where fog generated offshore by the cool Canary Current provides sufficient moisture to sustain a variety of lichens, succulents, and shrubs. It covers an area of 39,900 square kilometers (15,400 sq mi) in the south of Morocco and Mauritania. [39]

The North Saharan steppe and woodlands is along the northern desert, next to the Mediterranean forests, woodlands, and scrub ecoregions of the northern Maghreb and Cyrenaica. Winter rains sustain shrublands and dry woodlands that form a transition between the Mediterranean climate regions to the north and the hyper-arid Sahara proper to the south. It covers 1,675,300 square kilometers (646,840 sq mi) in Algeria, Egypt, Libya, Mauritania, Morocco, and Tunisia. [40]

The Sahara Desert ecoregion covers the hyper-arid central portion of the Sahara where rainfall is minimal and sporadic. Vegetation is rare, and this ecoregion consists mostly of sand dunes (erg, chech, raoui), stone plateaus (hamadas), gravel plains (reg), dry valleys (wadis), and salt flats. It covers 4,639,900 square kilometres (1,791,500 sq mi) of: Algeria, Chad, Egypt, Libya, Mali, Mauritania, Niger, and Sudan. [10]

The South Saharan steppe and woodlands ecoregion is a narrow band running east and west between the hyper-arid Sahara and the Sahel savannas to the south. Movements of the equatorial Intertropical Convergence Zone (ITCZ) bring summer rains during July and August which average 100 to 200 mm (4 to 8 in) but vary greatly from year to year. These rains sustain summer pastures of grasses and herbs, with dry woodlands and shrublands along seasonal watercourses. This ecoregion covers 1,101,700 square kilometres (425,400 sq mi) in Algeria, Chad, Mali, Mauritania, and Sudan. [41]

In the West Saharan montane xeric woodlands, several volcanic highlands provide a cooler, moister environment that supports Saharo-Mediterranean woodlands and shrublands. The ecoregion covers 258,100 square kilometres (99,650 sq mi), mostly in the Tassili n'Ajjer of Algeria, with smaller enclaves in the Aïr of Niger, the Dhar Adrar of Mauritania, and the Adrar des Iforas of Mali and Algeria. [42]

The Tibesti-Jebel Uweinat montane xeric woodlands ecoregion consists of the Tibesti and Jebel Uweinat highlands. Higher and more regular rainfall and cooler temperatures support woodlands and shrublands of date palm, acacias, myrtle, oleander, tamarix, and several rare and endemic plants. The ecoregion covers 82,200 square kilometres (31,700 sq mi) in the Tibesti of Chad and Libya, and Jebel Uweinat on the border of Egypt, Libya, and Sudan. [43]

The Saharan halophytics is an area of seasonally flooded saline depressions which is home to halophytic (salt-adapted) plant communities. The Saharan halophytics cover 54,000 square kilometres (21,000 sq mi) including: the Qattara and Siwa depressions in northern Egypt, the Tunisian salt lakes of central Tunisia, Chott Melghir in Algeria, and smaller areas of Algeria, Mauritania, and the southern part of Morocco. [44]

The Tanezrouft is one of the Sahara's most arid regions, with no vegetation and very little life. A barren, flat gravel plain, it extends south of Reggane in Algeria towards the Adrar des Ifoghas highlands in northern Mali.

The flora of the Sahara is highly diversified based on the bio-geographical characteristics of this vast desert. Floristically, the Sahara has three zones based on the amount of rainfall received – the Northern (Mediterranean), Central and Southern Zones. There are two transitional zones – the Mediterranean-Sahara transition and the Sahel transition zone. [45]

The Saharan flora comprises around 2800 species of vascular plants. Approximately a quarter of these are endemic. About half of these species are common to the flora of the Arabian deserts. [46]

The central Sahara is estimated to include five hundred species of plants, which is extremely low considering the huge extent of the area. Plants such as acacia trees, palms, succulents, spiny shrubs, and grasses have adapted to the arid conditions, by growing lower to avoid water loss by strong winds, by storing water in their thick stems to use it in dry periods, by having long roots that travel horizontally to reach the maximum area of water and to find any surface moisture, and by having small thick leaves or needles to prevent water loss by evapotranspiration. Plant leaves may dry out totally and then recover.

Several species of fox live in the Sahara including: the fennec fox, pale fox and Rüppell's fox. The addax, a large white antelope, can go nearly a year in the desert without drinking. The dorcas gazelle is a north African gazelle that can also go for a long time without water. Other notable gazelles include the rhim gazelle and dama gazelle.

The Saharan cheetah (northwest African cheetah) lives in Algeria, Togo, Niger, Mali, Benin, and Burkina Faso. There remain fewer than 250 mature cheetahs, which are very cautious, fleeing any human presence. The cheetah avoids the sun from April to October, seeking the shelter of shrubs such as balanites and acacias. They are unusually pale. [47] [48] The other cheetah subspecies (northeast African cheetah) lives in Chad, Sudan and the eastern region of Niger. However, it is currently extinct in the wild in Egypt and Libya. There are approximately 2000 mature individuals left in the wild.

Other animals include the monitor lizards, hyrax, sand vipers, and small populations of African wild dog, [49] in perhaps only 14 countries [50] and red-necked ostrich. Other animals exist in the Sahara (birds in particular) such as African silverbill and black-faced firefinch, among others. There are also small desert crocodiles in Mauritania and the Ennedi Plateau of Chad. [51]

The deathstalker scorpion can be 10 cm (3.9 in) long. Its venom contains large amounts of agitoxin and scyllatoxin and is very dangerous however, a sting from this scorpion rarely kills a healthy adult. The Saharan silver ant is unique in that due to the extreme high temperatures of their habitat, and the threat of predators, the ants are active outside their nest for only about ten minutes per day. [52]

Dromedary camels and goats are the domesticated animals most commonly found in the Sahara. Because of its qualities of endurance and speed, the dromedary is the favourite animal used by nomads.

Human activities are more likely to affect the habitat in areas of permanent water (oases) or where water comes close to the surface. Here, the local pressure on natural resources can be intense. The remaining populations of large mammals have been greatly reduced by hunting for food and recreation. In recent years development projects have started in the deserts of Algeria and Tunisia using irrigated water pumped from underground aquifers. These schemes often lead to soil degradation and salinization.

Researchers from Hacettepe University (Yücekutlu, N. et al., 2011) have reported that Saharan soil may have bio-available iron and also some essential macro and micro nutrient elements suitable for use as fertilizer for growing wheat. [53]

People lived on the edge of the desert thousands of years ago, [54] since the end of the last glacial period. The Sahara was then a much wetter place than it is today. Over 30,000 petroglyphs of river animals such as crocodiles [55] survive, with half found in the Tassili n'Ajjer in southeast Algeria. Fossils of dinosaurs, [56] including Afrovenator, Jobaria and Ouranosaurus, have also been found here. The modern Sahara, though, is not lush in vegetation, except in the Nile Valley, at a few oases, and in the northern highlands, where Mediterranean plants such as the olive tree are found to grow. It was long believed that the region had been this way since about 1600 BCE, after shifts in the Earth's axis increased temperatures and decreased precipitation, which led to the abrupt desertification of North Africa about 5,400 years ago. [31]

Kiffians

The Kiffian culture is a prehistoric industry, or domain, that existed between 10,000 and 8,000 years ago in the Sahara, during the Neolithic Subpluvial. Human remains from this culture were found in 2000 at a site known as Gobero, located in Niger in the Ténéré Desert. [57] The site is known as the largest and earliest grave of Stone Age people in the Sahara desert. [58] The Kiffians were skilled hunters. Bones of many large savannah animals that were discovered in the same area suggest that they lived on the shores of a lake that was present during the Holocene Wet Phase, a period when the Sahara was verdant and wet. [58] The Kiffian people were tall, standing over six feet in height. [57] Craniometric analysis indicates that this early Holocene population was closely related to the Late Pleistocene Iberomaurusians and early Holocene Capsians of the Maghreb, as well as mid-Holocene Mechta groups. [59] Traces of the Kiffian culture do not exist after 8,000 years ago, as the Sahara went through a dry period for the next thousand years. [60] After this time, the Tenerian culture colonized the area.

Tenerians

Gobero was discovered in 2000 during an archaeological expedition led by Paul Sereno, which sought dinosaur remains. Two distinct prehistoric cultures were discovered at the site: the early Holocene Kiffian culture, and the middle Holocene Tenerian culture. The post-Kiffian desiccation lasted until around 4600 BCE, when the earliest artefacts associated with the Tenerians have been dated to. Some 200 skeletons have been discovered at Gobero. The Tenerians were considerably shorter in height and less robust than the earlier Kiffians. Craniometric analysis also indicates that they were osteologically distinct. The Kiffian skulls are akin to those of the Late Pleistocene Iberomaurusians, early Holocene Capsians, and mid-Holocene Mechta groups, whereas the Tenerian crania are more like those of Mediterranean groups. [61] [62] Graves show that the Tenerians observed spiritual traditions, as they were buried with artifacts such as jewelry made of hippo tusks and clay pots. The most interesting find is a triple burial, dated to 5300 years ago, of an adult female and two children, estimated through their teeth as being five and eight years old, hugging each other. Pollen residue indicates they were buried on a bed of flowers. The three are assumed to have died within 24 hours of each other, but as their skeletons hold no apparent trauma (they did not die violently) and they have been buried so elaborately – unlikely if they had died of a plague – the cause of their deaths is a mystery.

Tashwinat Mummy

Uan Muhuggiag appears to have been inhabited from at least the 6th millennium BCE to about 2700 BCE, although not necessarily continuously. [63] The most noteworthy find at Uan Muhuggiag is the well-preserved mummy of a young boy of approximately 2 + 1 ⁄ 2 years old. The child was in a fetal position, then embalmed, then placed in a sack made of antelope skin, which was insulated by a layer of leaves. [64] The boy's organs were removed, as evidenced by incisions in his stomach and thorax, and an organic preservative was inserted to stop his body from decomposing. [65] An ostrich eggshell necklace was also found around his neck. [63] Radiocarbon dating determined the age of the mummy to be approximately 5600 years old, which makes it about 1000 years older than the earliest previously recorded mummy in ancient Egypt. [66] In 1958–59, an archaeological expedition led by Antonio Ascenzi conducted anthropological, radiological, histological and chemical analyses on the Uan Muhuggiag mummy. The specimen was determined to be that of a 30-month old child of uncertain sex, who possessed Negroid features. A long incision on the specimen's abdominal wall also indicated that the body had been initially mummified by evisceration and later underwent natural desiccation. [67] One other individual, an adult, was found at Uan Muhuggiag, buried in a crouched position. [63] However, the body showed no evidence of evisceration or any other method of preservation. The body was estimated to date from about 7500 BP. [68]

Nubians

During the Neolithic Era, before the onset of desertification around 9500 BCE, the central Sudan had been a rich environment supporting a large population ranging across what is now barren desert, like the Wadi el-Qa'ab. By the 5th millennium BCE, the people who inhabited what is now called Nubia, were full participants in the "agricultural revolution", living a settled lifestyle with domesticated plants and animals. Saharan rock art of cattle and herdsmen suggests the presence of a cattle cult like those found in Sudan and other pastoral societies in Africa today. [69] Megaliths found at Nabta Playa are overt examples of probably the world's first known archaeoastronomy devices, predating Stonehenge by some 2,000 years. [70] This complexity, as observed at Nabta Playa, and as expressed by different levels of authority within the society there, likely formed the basis for the structure of both the Neolithic society at Nabta and the Old Kingdom of Egypt. [71]

Egyptians

By 6000 BCE predynastic Egyptians in the southwestern corner of Egypt were herding cattle and constructing large buildings. Subsistence in organized and permanent settlements in predynastic Egypt by the middle of the 6th millennium BCE centered predominantly on cereal and animal agriculture: cattle, goats, pigs and sheep. Metal objects replaced prior ones of stone. Tanning of animal skins, pottery and weaving were commonplace in this era also. There are indications of seasonal or only temporary occupation of the Al Fayyum in the 6th millennium BCE, with food activities centering on fishing, hunting and food-gathering. Stone arrowheads, knives and scrapers from the era are commonly found. [72] Burial items included pottery, jewelry, farming and hunting equipment, and assorted foods including dried meat and fruit. Burial in desert environments appears to enhance Egyptian preservation rites, and the dead were buried facing due west. [73]

By 3400 BCE, the Sahara was as dry as it is today, due to reduced precipitation and higher temperatures resulting from a shift in the Earth's orbit. [31] As a result of this aridification, it became a largely impenetrable barrier to humans, with the remaining settlements mainly being concentrated around the numerous oases that dot the landscape. Little trade or commerce is known to have passed through the interior in subsequent periods, the only major exception being the Nile Valley. The Nile, however, was impassable at several cataracts, making trade and contact by boat difficult.

Phoenicians

The people of Phoenicia, who flourished from 1200 to 800 BCE, created a confederation of kingdoms across the entire Sahara to Egypt. They generally settled along the Mediterranean coast, as well as the Sahara, among the people of ancient Libya, who were the ancestors of people who speak Berber languages in North Africa and the Sahara today, including the Tuareg of the central Sahara.

The Phoenician alphabet seems to have been adopted by the ancient Libyans of north Africa, and Tifinagh is still used today by Berber-speaking Tuareg camel herders of the central Sahara.

Sometime between 633 BCE and 530 BCE, Hanno the Navigator either established or reinforced Phoenician colonies in Western Sahara, but all ancient remains have vanished with virtually no trace.

Greeks

By 500 BCE, Greeks arrived in the desert. Greek traders spread along the eastern coast of the desert, establishing trading colonies along the Red Sea. The Carthaginians explored the Atlantic coast of the desert, but the turbulence of the waters and the lack of markets caused a lack of presence further south than modern Morocco. Centralized states thus surrounded the desert on the north and east it remained outside the control of these states. Raids from the nomadic Berber people of the desert were of constant concern to those living on the edge of the desert.

Urban civilization

An urban civilization, the Garamantes, arose around 500 BCE in the heart of the Sahara, in a valley that is now called the Wadi al-Ajal in Fezzan, Libya. [25] The Garamantes achieved this development by digging tunnels far into the mountains flanking the valley to tap fossil water and bring it to their fields. The Garamantes grew populous and strong, conquering their neighbors and capturing many slaves (who were put to work extending the tunnels). The ancient Greeks and the Romans knew of the Garamantes and regarded them as uncivilized nomads. However, they traded with them, and a Roman bath has been found in the Garamantes' capital of Garama. Archaeologists have found eight major towns and many other important settlements in the Garamantes' territory. The Garamantes' civilization eventually collapsed after they had depleted available water in the aquifers and could no longer sustain the effort to extend the tunnels further into the mountains. [74]

Between the first century BC and the fourth century AD, several Roman expeditions into the Sahara were conducted by groups of military and commercial units of Romans.

Berbers

The Berber people occupied (and still occupy with Arabs) much of the Sahara. The Garamantes Berbers built a prosperous empire in the heart of the desert. [75] The Tuareg nomads continue to inhabit and move across wide Sahara surfaces to the present day.

Islamic and Arabic expansion

The Byzantine Empire ruled the northern shores of the Sahara from the 5th to the 7th centuries. After the Muslim conquest of Arabia, specifically the Arabian peninsula, the Muslim conquest of North Africa began in the mid-7th to early 8th centuries and Islamic influence expanded rapidly on the Sahara. By the end of 641 all of Egypt was in Muslim hands. Trade across the desert intensified, and a significant slave trade crossed the desert. It has been estimated that from the 10th to 19th centuries some 6,000 to 7,000 slaves were transported north each year. [76]

Ottoman Turkish era

In the 16th century the northern fringe of the Sahara, such as coastal regencies in present-day Algeria and Tunisia, as well as some parts of present-day Libya, together with the semi-autonomous kingdom of Egypt, were occupied by the Ottoman Empire. From 1517 Egypt was a valued part of the Ottoman Empire, ownership of which provided the Ottomans with control over the Nile Valley, the east Mediterranean and North Africa. The benefit of the Ottoman Empire was the freedom of movement for citizens and goods. Traders exploited the Ottoman land routes to handle the spices, gold and silk from the East, manufactured goods from Europe, and the slave and gold traffic from Africa. Arabic continued as the local language and Islamic culture was much reinforced. The Sahel and southern Sahara regions were home to several independent states or to roaming Tuareg clans.

European colonialism

European colonialism in the Sahara began in the 19th century. France conquered the regency of Algiers from the Ottomans in 1830, and French rule spread south from French Algeria and eastwards from Senegal into the upper Niger to include present-day Algeria, Chad, Mali then French Sudan including Timbuktu (1893), Mauritania, Morocco (1912), Niger, and Tunisia (1881). By the beginning of the 20th century, the trans-Saharan trade had clearly declined because goods were moved through more modern and efficient means, such as airplanes, rather than across the desert. [77]

The French took advantage of long-standing animosity between the Chaamba Arabs and the Tuareg. The newly raised Méhariste camel corps were originally recruited mainly from the Chaamba nomadic tribe. In 1902, the French penetrated Hoggar Mountains and defeated Ahaggar Tuareg in the battle of Tit.

The French Colonial Empire was the dominant presence in the Sahara. It established regular air links from Toulouse (HQ of famed Aéropostale), to Oran and over the Hoggar to Timbuktu and West to Bamako and Dakar, as well as trans-Sahara bus services run by La Compagnie Transsaharienne (est. 1927). [78] A remarkable film shot by famous aviator Captain René Wauthier documents the first crossing by a large truck convoy from Algiers to Tchad, across the Sahara. [79]

Egypt, under Muhammad Ali and his successors, conquered Nubia in 1820–22, founded Khartoum in 1823, and conquered Darfur in 1874. Egypt, including the Sudan, became a British protectorate in 1882. Egypt and Britain lost control of the Sudan from 1882 to 1898 as a result of the Mahdist War. After its capture by British troops in 1898, the Sudan became an Anglo-Egyptian condominium.

Spain captured present-day Western Sahara after 1874, although Rio del Oro remained largely under Sahrawi influence. In 1912, Italy captured parts of what was to be named Libya from the Ottomans. To promote the Roman Catholic religion in the desert, Pope Pius IX appointed a delegate Apostolic of the Sahara and the Sudan in 1868 later in the 19th century his jurisdiction was reorganized into the Vicariate Apostolic of Sahara.


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On 2-3 June 2021, GLF will host the first-ever digital conference focused entirely on Africa’s drylands and how integrative restoration practices can see them flourish once again. Join in for inspiring speakers, the latest science, concerts, film screenings, virtual tours, networking, and the unexpected discoveries that always form part of a Global Landscapes Forum event.

GLF Africa: Restoring Africa’s Drylands will be held just before the official launch of the UN Decade on Ecosystem Restoration, which runs from 2021 to 2030.


Finding wonder on our shores – more unlikely UK landscapes

Temperate rainforest

Wistman’s Wood, Dartmoor, in January 2020. Photograph: Will Tudor/Getty Images/iStockphoto

A dwarf jungle of contorted green limbs clustered with mosses, lichens and ferns, Wistman’s Wood on Dartmoor is among Britain’s best-known examples of temperate rainforest. The clue is the presence of epiphytes – plants that grow on other plants. Patches of temperate rainforest can also be found in Wales, on the Atlantic coast of Scotland, and in Cornwall and Cumbria. Rainforests seem to belong to somewhere far away, but their existence should hardly be surprising in a place where it rains all the time.

Arctic tundra

Cairngorm mountains. Photograph: Murdo MacLeod/The Guardian

The Cairngorm plateau, the highest and coldest upland area in Britain, is defined as “arctic-alpine tundra”, meaning it is climatologically and ecologically closer to Scandinavia, Siberia or Alaska than it is to the neighbouring Highlands. Shaped by glaciers in the last ice age, the tundra’s weave of mosses and lichens support Arctic species such as Lapland bunting, snow bunting and dotterel, as well as Britain’s only free-roaming herd of reindeer.

Walker above Carlingford Lough. Photograph: Gareth McCormack/Alamy

Fjords – narrow, steep-sided inlets carved out of the rock by glaciers – are indelibly associated with the coastline of Norway, but a fjord also forms part of a UK border: the 10-mile-long Carlingford Lough, which separates County Down in Northern Ireland from County Lough in the Irish Republic. It may not have the cliff-sided drama of the Norwegian fjords but it is a reminder of the great glaciers that covered much of the region in the last ice age, and once formed a frozen bridge to Scandinavia and Eurasia.

This is an edited extract from the introduction of Nick Hunt’s new book Outlandish, (John Murray, £16.99) published on 27 May


Libya's Pivot Irrigation in the Sahara Proves Money Can Do Anything

Libya, in North Africa, now drilling for oil with BP is a country that is not exactly known for having ample quantities of fresh water let alone enough water to be used to any extent in agriculture. Yet this North African desert country, ruled by a man who most people consider to be a bit “eccentric” (if not entirely off the wall) has been involved for years in growing crops by a method known as pivot irrigation.

Center pivot irrigation piping: the water comes from here.

For those who are not aware of how this energy-intensive system works, it is designed to minimize water loss through evaporation, by utilizing a combination of sprinkler and drip irrigation methods that feeds water from a pivot point within a circle.

The water being fed to the crops is measured and dispersed from a series of circular pipes that are rotated on wheeled platforms the gradually moved out from the center of the circle the place where the water originated from. By using this circular rotation method, less water is wasted and the crops inside the circular agricultural plot are able to receive the maximum amount of water available.

Although used in a number a number of countries, including India and desert regions of the USA, the use of this method to grow crops is so unique in Libya, that the circular pivot irrigation fields are often photographed by both orbiting satellites and NASA space shuttles passing overhead.

In a country like Libya, where more than 95% of the country consists of the near-waterless Sahara, this type of agriculture is not cheap, and is only possible by being able to tap underground fossil water deposits from a large underground aquifer like they’ve done in the Great Man Made River project. Each circular plot is about 1 km in diameter, and is able to grow a number of different crops include grains, fruits and vegetables, and crops for animal fodder.

Pivot irrigation in Jordan.
Image via Manufactured Landscapes blog. A cool site that looks at man-made structures on earth using Google maps.

Libya is not the only Middle Eastern country trying to “green the desert” through the use of irrigation. Jordan is also practicing pivot irrigation (see above image) Israel has been irrigating for years via its patented “drip irrigation” methods through companies like Plastro and Netafim are now being used in arid regions all over the world, even in arch enemy countries like Syria, and other regional countries, including Qatar in the Persian Gulf region which is teaming up with Syria on agriculture projects intended to “green the desert.”

But none of these countries, except for Libya, have these circular pivot irrigated fields which can actually be seen from above by orbiting astronauts. No one really knows how much Libyan President Muammar al-Gaddafi has spent on these projects, which are probably costing a lot more than simply importing the crops his country needs. But when one is sitting on what is still one of the world’s largest oil reserves (at least 10% of the world’s oil) then anything is possible – as long as the oil holds out.


Watch the video: The Third Industrial Revolution: A Radical New Sharing Economy (May 2022).