The Sahara Desert has Grown 10% Since the 1920s

The Sahara Desert has expanded by about 10 percent since 1920, according to a new study by National Science Foundation (NSF)-funded scientists at the University of Maryland (UMD).

The research is the first to assess century-scale changes to the boundaries of the world's largest desert. It suggests that other deserts could be expanding as well. The study is published today in the Journal of Climate.

"The trends in Africa of hot summers getting hotter and rainy seasons drying out are linked with factors that include increasing greenhouse gases and aerosols in the atmosphere," says Ming Cai, a program director in NSF's Division of Atmospheric and Geospace Sciences, which funded the research. "These trends have a devastating effect on the lives of African people, who depend on agriculture-based economies."

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The Sahara Fertilizes & Poisons the Caribbean

Dust from the Saharan desert is bringing needed iron and other nutrients to underwater plants in the Caribbean, but bacteria may be the first thing to prosper from that dust.

The dust is causing the bacteria to bloom and also become more toxic to humans and marine organisms.

"This has been going on for a long time, but nobody understood it," said Florida State University Professor of Chemical Oceanography William Landing, a co-author on a new paper outlining the effect of the dust. "It's a natural phenomenon."

The new research was published in the May 9 edition of the Proceedings of the National Academy of Sciences.

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Should Europe Cover the Sahara With Solar Panels for Power?

Could one solution to climate change be to harvest the power of sunlight where it shines brightest on the planet? Should we solar panel the Sahara desert?

Four experts discuss the radical proposal with the BBC World Service Inquiry programme.

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French Architecture Firm Rediscovers Arcologies in Quest for 'Sustainable' Cities in the Sahara

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Sahara may Date Back to Miocene Neogene

The desertification of northern Africa may have started 7 million years ago, or more than twice as long ago as earlier estimates of the Sahara's age, climate simulations suggest. The findings also hint that this shift in climate would have been triggered by the gradual shrinking of the Tethys Sea, the predecessor of today’s Mediterranean.

The sands of the Sahara may seem timeless, but most geological data suggests that the world's largest non-polar desert formed between 2 million and 3 million years ago, about the same time as cycles of ice ages began plaguing the Northern Hemisphere.

Still, scientists have unearthed tantalizing clues that the Sahara may be much older than 3 million years old, says Zhongshi Zhang, a palaeoclimatologist at the Bjerknes Center for Climate Research in Bergen, Norway and a a co-author of the latest study, published on September 17 in Nature. Almost a decade ago, he notes, one team reported evidence of widespread dune deposits estimated to be 7 million years old in northern Chad.

Other analyses, including of long-term variations in the amounts of dust and pollen in sediments drilled from seafloors off northern Africa, chronicle extended dry spells in the region starting about 8 million years ago.

But it has been unclear what might have triggered the aridification, says Zhang. There were no major episodes of mountain formation that might have influenced climate in the region, he notes. Nor do his team's climate simulations suggest that long-term changes in Earth’s orbit or atmospheric concentrations of carbon dioxide are to blame.

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Meet the Neolithic Artists of Eastern Sahara

Recently discovered rock art on the walls of a cave in the Egyptian Western Desert has been provisionally dated by a Cambridge University archaeologist as between 6,000 and 7,000 years old, created at least 1,000 years before the building of the pyramids. The drawings add weight to the argument that Egyptian culture drew on cultural influences from Africa and not only from the Near East.

Spotted by a tourist to Wadi el Obeiyid, north of Farafra Oasis, drawings of a giraffe, a bovid (cow-like mammal) and two boats, plus the outline of a human hand, were examined last month by Dr Giulio Lucarini who co-leads a team of archaeologists looking at the pathways, and timings, by which domestic animals and plants from the Levant arrived in Egypt. The engravings are thought to have been discovered in 2010. The onset of revolution in Egypt meant that they were not investigated for some time.

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A Marine Refuge During the Serpukhovian Carboniferous Mass Extinction?

The Tindouf Basin, a marine refuge during the Serpukhovian (Carboniferous) mass extinction in the northwestern Gondwana platform

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Cózar et al

Abstract:

Several macrofaunas and microfossils of the Carboniferous Saharan basins have longer stratigraphic ranges than those of other basins in the western Palaeotethys realm, particularly in the Tindouf Basin (Morocco–Algeria). Foraminifers are particularly abundant and diverse in the Serpukhovian and basal Bashkirian compared to coeval basins, and some taxa have longer ranges than in the neighbouring Reggan and Béchar basins, although this effect is more marked compared to the western Palaeotethyan assemblages in Europe. Several rugose coral species are recorded from the early Bashkirian that previously were considered to have disappeared in the Serpukhovian. The Tindouf Basin, as one of the most western Saharan basins in North Africa, shows the greatest stratigraphic ranges of taxa which diminish eastwards. Evidence for a mass extinction event during the Serpukhovian in the Tindouf Basin has not been clearly recognized, although a possible influence of glaciation is observed in the faunal diversity. Eustatic sea-level changes were experienced in Tindouf with the cyclic pattern of sedimentation, but warm water ocean currents from the palaeoequator were able to maintain tropical conditions on the platform. Tectonics in the area, led to emerging land masses and barriers, and created a partly isolated basin in this sector of the western part of the Sahara Platform in northern Gondwana. The combination of those factors controlled the environmental conditions in the area, allowing the persistence of the fauna for longer stratigraphic ranges than its equivalent counterparts in the western Palaeotethys.

Were There Three Major Rivers in the Sahara During the Last Interglacial?

Three ancient river systems, now buried, may have created viable routes for human migration across the Sahara to the Mediterranean region about 100,000 years ago, according to research published September 11 in the open access journal PLOS ONE by Tom Coulthard from the University of Hull, UK, and colleagues from other institutions.

Simulating paleoclimates in the region, the researchers found quantitative evidence of three major river systems that likely existed in North Africa 130,000-100,000 years ago, but are now largely buried by dune systems in the desert. When flowing, these rivers likely provided fertile habitats for animals and vegetation, creating 'green corridors' across the region. At least one river system is estimated to have been 100 km wide and largely perennial. The Irharhar river, westernmost of the three identified, may represent a likely route of human migration across the region. In addition to rivers, the researchers' simulations predict massive lagoons and wetlands in northeast Libya, some of which span over 70,000-square kilometers. "It's exciting to think that 100 000 years ago there were three huge rivers forcing their way across a 1000km of the Sahara desert to the Mediterranean -- and that our ancestors could have walked alongside them" said Coulthard.

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Meet The Sahara Forest Project: A Biosphere 2 for the 21st Century?

A renewable-energy "oasis" slated to be built in 2010 may serve as a proving ground for new technologies designed to bring green living to the desert.

The planned research center is part of the Sahara Forest Project—but that doesn't mean it'll be built in Africa. Sahara means "desert" in Arabic, and the center is meant to be a small-scale version of massive green complexes that project managers hope to build in deserts around the globe.

(See pictures of the planned Sahara Forest Project reseach center.)

Experts are now examining arid sites in Australia, the U.S., the Middle East, and Africa that could support the test facility.

"The Sahara Forest Project is a holistic approach for creation of local jobs, food, water, and energy, utilizing relatively simple solutions mimicking design and principles from nature," said Frederic Hauge, founder and president of the Norwegian environmental nonprofit the Bellona Foundation.

For instance, special greenhouses would use hot desert air and seawater make fresh water for growing crops, solar energy would be collected to generate power, and algae pools would offer a renewable and easily transportable fuel supply.

In addition, planting trees near the complex would trap atmospheric greenhouse gases such as carbon dioxide while restoring any natural forest cover that has been lost to drought and timber harvesting.

(Related: "Africa-wide 'Great Green Wall' to Halt Sahara's Spread?")

"From my perspective as an environmentalist, this could be a game changer in how we produce biomass for food and energy, and how we're going to provide fresh water for the future," Hauge said. "I've never been so engaged and fascinated as I am now."

But not all experts are as enthusiastic about the project.

In terms of the reforestation plans, "trying to grow trees in the Sahara desert is not the most appropriate approach," said Patrick Gonzalez, a forest ecologist at the University of California, Berkeley's Center for Forestry. After all, even though it was literally green in the past, the Sahara was never heavily forested. (See an interactive Sahara map.)

"I can imagine that this scheme and type of technology in limited cases might work in certain areas like Dubai, where they're used to making palm-shaped islands and 160-story-tall buildings," Gonzalez said.

If the goal is restoring a desert's natural ecosystem, however, "it would be more effective, but less flashy, to work with local people on community-based natural-resource management."

From Nat Geo and the project website (prepare to be flashed to death).

So, Biosphere/2 of the 21st century?