Imagine this. Ten thousand years from now, one of your descendants decides to take a trip to the great Sahara Desert. The only problem is that the 3.6 million square miles of rock and dunes covering much of North Africa will no longer be Sahara - the Desert. It will be Sahara - the Forest. Crazy, you say? Not At All.
Dr Curt Stager at Paul Smiths College has been researching how climate change can bring about a massive change in our Earth’s topography, turning the deserts green and making oceans volatile. Through Stager’s study, he has deduced that “As we heat the planet, the central climate belt that girdles the Earth, which is a rain belt basically where the rain forests are located, is getting broader. That’s pushing into the southern bounds of the Sahara.”
The likeliness of this happening is very high because as you all may know that around 8,000 years ago, the present-day Sahara Desert was, in fact, a luscious green forest.
Sahara Desert - Dust Thou Art, To Dust Returnest (Only Reverse)
Researchers at MIT have been studying and researching the dust that has been present on the coast of West Africa for the last 240,000 Years. They found that the Sahara and North Africa as a whole have experienced both wet and dry climates every 20,000 years.
This is caused because of the changes in the Earth’s axis as it orbits the sun. This affects the distribution of sunlight between seasons. The Earth likely tilts in some years to receive maximum summer sunlight. This may increase the monsoon activity that is crucial for a wetter and greener Sahara.
Wright's Theory and Sahara Desert
David Wright, an environmental archaeologist at Seoul National University, said that humans living near the Nile river travelled west. They took along with them some sheep, cows and goats that ate and stomped over the vegetation there transforming the landscape and the climate.
Goats played the most critical role in this. They could eat even a brick. Wright says, “They aren’t picky eaters at all, and they eat a lot for their size. It wouldn’t take many goats on a stressed-out landscape to make a pretty big impact.”
The local climate change was caused because herds of goats and other mammals exposed the previously hidden land under the lush green trees for years before. The once dense forest that covered the ground beneath provided food and shelter were absolutely crushed and torn apart by animals and of course, us humans.
Temperature and the Sahara Desert Are Intertwined
On hot, sunny days we prefer to wear light clothes as it reflects the light. The same thing happens with the Earth’s surface. The sand and the light brown colour reflect the sunlight more than the viridescent grass and bush.
Since there were fewer clouds, the amount of rainfall decreased, causing Sahara to be a desert. It is believed that because of overgrazing, there was drought. The drought caused the vegetation to be stunted, which transformed the Sahara landscape, worsening the deficit.
Therefore, this vicious cycle produced a scorching, dry, dusty desert that is roughly the size of the entire United States Wright says that it was the human migration that caused the region to a tipping point. The landscape was expected to transform slowly and uniformly due to the variations in the Earth’s orbit. Instead, it changed rapidly due to the spread of livestock.
Jon Foley's Study
A climatologist and executive director at the California Academy of Sciences, Jon Foley says that the study could explain the phenomena of loss of vegetation across Sahara due to Earth’s orbit changes.
Like the basic studied in our school, plants soak up moisture from the ground and release it by the leaves. This adds water vapour to the atmosphere. Therefore, when the Sahara vegetation disappeared, drought worsened as the atmosphere lost the most important source of water.
The loss of vegetation is affecting us in the present too. Scientists believe that the deforestation of the Amazon and the frequent fires have fuelled drought in the region. The Amazon contains enormous amounts of carbon pollution. Deforestation of that is acceleration global warming.