On Wednesday, December 2nd, Discovery will present a global broadcast of Racing Extinction, a powerful eco-thriller from Academy Award-winning director, Louie Psihoyos. Inspired by the message in the film, #StartWith1Thing is a call-to-action to each and every one of us across the globe to make small changes in our lives that will have a huge impact on the world.
Related on TestTube
Why is the Antarctic Growing?
Are Humans Really Responsible for Climate Change?
Today's episode of DNews is in collaboration with the documentary Racing Extinction to take a look at the disturbing trend of growing deserts around the world. Our planet is a constantly shifting landscape of eight biomes: tundras, taigas, deciduous forests, scrub forests, grasslands, tropical rain forest, temperate rain forest and deserts. Climates change, sometimes very dramatically, as us the case with the Earth's deserts, which are completely shifting their borders right now. It's hard to imagine, but the massive Sahara desert was green and lush just a few thousand years ago. Scientists had long hypothesed that an ancient river ran through the Western Sahara, keeping it teeming with life. A recent study by the Japanese Advanced Land Observing Satellite used microwave radar to confirm that the Tamanrassat river wound 300 miles (500 km) inland to the Mauritanian coast.
In a study recently published by Earth and Planetary Science Letters looked at 30,000 years of dust blown from Africa into the Atlantic. Over the millennia the amount of dust blown into the ocean rose and fell in accordance to the amount of moisture on the continent; in periods of less moisture there was more dust, and vice versa. Today, because it's so dry, the majority of the sediment in the Atlantic is Saharan dust. By studying this dust, they know about 6,000 years ago the African Humid Period ended suddenly, coinciding with an axial change in the Earth's orbit. According to researcher, the Sahara exists, in part, because the Earth's spin changed, decreasing Northern Hemisphere monsoons, and causing the Sahara to grow. Vegetation died very quickly and the third largest desert in the world took over North Africa in less than 300 years. A separate study in the journal Science, found one of the jet streams which moves hot dry air across the planet's Equator shifted northward, causing the tropics to expand 140 miles northward in the last 26 years, along with the deserts. Researchers aren't exactly sure why, but they know global warming is one factor, as is the Earth's rotation. As the distribution of ice and water on the planet changes, the Earth's axis changes in a process called precession. In turn, the sun will hit different latitudes our planet at different intensities than before--drastically changing the weather systems and our overall climate. Whether it's natural or man-made, the jetstream is already shifting causing the tropical deserts to expand into previously lush territory, but scientists are pretty sure this is happening way too fast.
For more on Racing Extinction, check out the website and follow @RacingXtinction on Twitter.
Deserts Might Grow as Tropics Expand (Live Science)
"Rivers of air that move both storms and airplanes around the planet have been creeping poleward over the past 26 years. The migration of these so-called "jet streams" has widened the planet's tropical belt and could expand dry regions around the world in coming decades, a new study reports."
Deserts set to expand (Nature)
"Many of the world's dry regions, currently home to some 2.1 billion people, are in danger of becoming useless for growing food, according to the latest in a series of reports on the world's ecosystems. It blames climate change and human activities."