Paleoclimate and archaeological evidence tells us that, 11,000-5,000 years ago, the Earth's slow orbital 'wobble' transformed today's Sahara desert to a land covered with vegetation and lakes.
There was plenty of rain in the Sahara, so nobody needed the Nile. The Holocene Wet Phase lasted for more than 6500 years, until middle of 4th millennium BC (about 3500 BC, 5500 years ago), when the amount of rain falling dropped dramatically.
A new paper in the Bulletin of the American Museum of Natural History describes the Trans-Saharan Seaway that existed 50 to 100 million years ago in the region of the current Sahara Desert.
"We know that 6,000 years ago, what is now the Sahara Desert was a rainy place," Korty adds. "It has been something of a mystery to understand how the tropical rain belt moved so far north of the equator.
As recently as 5,000 years ago, one of the world's driest and most uninhabitable places, the Western Sahara desert, was home to a vast river system that would rank as the world's 12th largest drainage basin if it existed today.
The Sahara is the world's largest hot desert, but parts of it could be made green if massive solar and wind farms set up shop there, a new study finds.
The next Northern Hemisphere summer insolation maximum — when the Green Sahara could reappear — is projected to happen again about 10,000 years from now in A.D. 12000 or A.D. 13000. But what scientists can't predict is how greenhouse gases will affect this natural climate cycle.
Today, the Sahara Desert is defined by undulating sand dunes, unforgiving sun, and oppressive heat. But just 10,000 years ago, it was lush and verdant. So, what spurred the shift from woodland to wasteland? A new study suggests humans played a big role.
As little as 6,000 years ago, the vast Sahara Desert was covered in grassland that received plenty of rainfall, but shifts in the world's weather patterns abruptly transformed the vegetated region into some of the driest land on Earth.
Snowfall in a hot desert may seem a contradiction but snow has been recorded several times in the Sahara Desert over the last decades, most recently in January 2022. Thus, snowfall may be unusual but is not unprecedented in the region.
All this has been known for decades. But between 8,000 and 4,500 years ago, something strange happened: The transition from humid to dry happened far more rapidly in some areas than could be explained by the orbital precession alone, resulting in the Sahara Desert as we know it today.
Beneath the sands of the Sahara Desert scientists have discovered evidence of a prehistoric megalake. Formed some 250,000 years ago when the Nile River pushed through a low channel near Wadi Tushka, it flooded the eastern Sahara, creating a lake that at its highest level covered more than 42,000 square miles.
In De-Nile
The Nile Valley was the seat of an ancient Egyptian civilization that spanned over 4,000 years. In 3,000 B.C.E., Egypt looked similar geographically to the way it looks today. The country was mostly covered by desert.
The greening of the Sahara, associated with the African Humid Period (AHP) between ca. 14,500 and 5,000 y ago, is arguably the largest climate-induced environmental change in the Holocene; it is usually explained by the strengthening and northward expansion of the African monsoon in response to orbital forcing.
Now researchers at MIT have analyzed dust deposited off the coast of west Africa over the last 240,000 years, and found that the Sahara, and North Africa in general, has swung between wet and dry climates every 20,000 years.
The Sahara — the world's biggest hot desert — is getting even bigger. In fact, it is currently about 10 percent larger than it was nearly a century ago, and scientists suggest that climate change is partly responsible.
At the end of the last Ice Age, the Sahara Desert was just as dry and uninviting as it is today.
The region now holding the Sahara Desert was once underwater, in striking contrast to the present-day arid environment. This dramatic difference in climate over time is recorded in the rock and fossil record of West Africa during a time range that extends through the Cretaceous-Paleogene (KPg) boundary.
How Hot Is The Sahara Desert? The Sahara is the hottest desert in the world – with one of the harshest climates. The average annual temperature is 30°C, whilst the hottest temperature ever recorded was 58°C.
The searing heat waves that blanketed the nation earlier this summer sent temperatures soaring well above 110°F in parts of the U.S., but that's nowhere close to the hottest temperature on record — an almost unimaginable 136.4° F, taken on September 13, 1922, in the Sahara Desert at El Azizia, Libya.
Deserts are not dried up oceans. This is because deserts are found on continents and oceans lie between continents.
The human body can survive for about three days without water, which can be extremely hard to find in hot desert climates. If you're ever lost in a desert, knowing how to quickly find water is key to your survival. Water flows down, so check low terrain.
If one measures from the bedrock up to an erg, the depth of the Sahara can be said to be between 21 and 43 meters. However, the sand dunes have an average height of 150 meters from the bedrock, and in windswept conditions, the height of the sand dunes can reach up to 320 meters.
Over the last two decades, the Earth has seen an increase in foliage around the planet, measured in average leaf area per year on plants and trees. Data from NASA satellites shows that China and India are leading the increase in greening on land.