Live Wilderness Adventure

Chapter 810 Begins with continental drift.

Five p.m.

It was the hottest time of the day, so Bi Fang and the camel hid under a rock wall to enjoy the cool.

The best time of day to drive is from 4:00 am to 11:00 am, and then from 4:00 pm to 7:00 pm. You can also drive overnight, but as I said, it is the peak period of animal activity, so the risk is relatively high. , and in a dark environment, it is easier for people to bear greater mental stress.

And people always need to rest. We are not camels. It is impossible to go for days without eating and drinking. It is very cold in the Sahara at night. In the cold environment, sleep as much as possible. The heat you lose from excessive activity is not recycled. Regenerate.

Don't worry you'll sleep forever in your sleep, unless you're exhausted, you'll be frozen awake before you're frozen.

Bi Fang took a sip of water, his forearm drooped naturally, and placed it on his knees, squinting his eyes at the scorching sun outside the shadows, where there were heat waves and deserts everywhere.

If it is a trip, following a large team and a camel team, it will naturally be an incomparably stalwart natural scenery, broaden your horizons and body and mind, but if you are alone, you may be full of despair, right?

Bi Fang screwed on the kettle and pointed to the vast desert in front of him: Can you imagine that the Sahara, which is now full of sand dunes, was actually a dense forest before.

[I can imagine, I thought of it]

【Save face, God Fang doesn't want to see your reaction】

[Spaghetti should be mixed with No. 42 concrete]

[Although I can't believe it, I'm not an idiot. When Lao Fang said this, I knew it was outrageous and true (dog head)]

【Reason tells me to accept it】

The barrage is always weird, and Bi Fang, who has long been used to it, did not interrupt his narration.

Each year hundreds of millions of tons of dust are carried away from the Sahara by the northeast trade winds, much of which is deposited in the Atlantic,

Through the study of ancient sediments, scientists have found that in the past hundreds of thousands of years, the climate of the Sahara has been regularly switching between dry and wet, with a time period of more than 20,000 years.

And the ancient murals found in the Sahara Desert also confirmed this phenomenon from the other hand. Many horses, buffaloes, elephants, giraffes and other animals appeared in these murals, and we all know that these animals are impossible. Survive in the desert, especially horses.

About 40,000 to 20,000 years ago, the Sahara region was still in a humid climate period. At that time, plants were lush, rivers were criss-crossing, lakes were clustered, and floods were frequent.

And in the period from 20,000 to 10,000 years ago, the climate here became drier, plants became scarce, and the rivers became dry valleys without water.

After this dry period, the climate became humid again. Around 3500 BC, the rainfall was abundant, the vegetation was lush, the lakes and rivers were full, and the water area reached its maximum.

But after that, strong winds returned to this land, and the lush forests became grasslands, which became a paradise for cattle, sheep, antelopes, and giraffes. Animals such as hippos and buffaloes disappeared, and the fishing industry ceased to exist.

After 2000 BC, the climate became more dry, and grassland animals also withdrew from the stage. Rivers stopped flowing, lakes became smaller, dried up or disappeared, vegetation withered and degraded, and the grassland completely turned into desert. Many grassland animals were forced to withdraw from the Sahara. stage of history.

Until now, the Sahara has completely become the largest and most typical tropical dry area in the world.

[Why did it become like this, is it simply due to the climate, or what? 】

【Environmental damage? 】

[Not necessarily, the Sahara seems to be like this a long time ago]

It's not environmental damage, but the climate. If we want to talk about the root cause, it should be the shrinking of the Tethys Sea.

【what what what】

[Another thing I have never heard of]

[Is there such a sea on earth? 】

Used to have.

Bi Fang grabbed a handful of sand and slid it down slowly.

Due to the movement of the earth's plates, the land on the earth has been moving slowly. 40 million years ago, the plate where Africa was located was not in the position we see now. There was a wide ocean in the north of it. It is the Tethys Sea.

Under the nourishment of a large amount of humid air from the ocean, there was no Sahara desert in northern Africa at that time, but a large oasis.

However, from 40 million years ago, the plate where Africa was located began to move northward continuously. Over time, it finally hit the plate where Europe was located, which caused the closure of the Tethys Sea, and Africa The northern part of the plate where it is located has also been lifted due to compression, and more land has been exposed to the sea.

The contraction of the Tethys Sea not only caused a change in the mean climate state in North Africa, but also strengthened the response of the African summer monsoon to orbital changes, which subsequently became the main factor controlling the change in the extent of the Sahara Desert.

[Tian Ling Gai flew into a strange thing]

【I seem to have glimpsed the truth of the world】

【Oops, my brain is about to grow out】

If the contraction of the Tethys Sea is the root cause, then the Earth's precession is the direct cause of the regular switching of the Sahara's climate.

The so-called precession of the earth means that the axis of rotation of the earth will rotate around the axis of revolution of the earth under the influence of the gravitational force of the sun and the moon. The trajectory of this rotation in space is a conical surface, and its period is about 25,700 years.

We know that the sun's energy harvested is highest at the direct sunlight position on the earth, and as the sun's obliquity increases, the sun's energy harvested decreases.

Earth precession changes the inclination of sunlight in the same season on Earth, which affects the distribution of solar energy on Earth between seasons.

That is to say, the precession of the earth will cause the sunlight energy in the same area on the earth to appear in the same season in such a regular fluctuation as 'from less to more, and from more to less', while for the area where the Sahara is located In other words, this will directly affect the strength of the summer monsoon.

In fact, it is sea breeze and land breeze. If the summer monsoon is not enough, the sea breeze will be weak, and there will not be enough humid air from the ocean to enter the land. Slowly, it will become dry.

Perhaps thousands of years later, this place will turn into a wet forest again and become a paradise for animals.

【Fuck, I've never learned these things.】

[Be confident, high school geography doesn't teach this]

[If I'm still a high school student, I'm sorry about this topic, even if I'm a high school student, I can't say a few words about this topic. 】

[No, what sea contracted 40 million years ago, why did it become a desert 40,000 years ago? 】

Because shrinkage is just the beginning, continental movement is a slow process. It was not until the Toltonian stage in the late Miocene, about 7 million to 11 million years ago, that the sea shrank almost, and the source of water vapor was completely cut off.

The reason why the cycle only started 40,000 years ago is related to the meteorological history of the earth. In fact, what you see more now is that the annual summer monsoon or any prevailing wind belt was formed in the past tens of thousands of years.

Forty thousand years ago, the earth was still in the ice age, and it had lasted for millions of years before, and there was no so-called summer monsoon at all.

The audience fell into a state of dementia.

This starts from continental drift, continues to climate change, and then to the history of the earth. It is not necessarily clear to those who have not done professional research.

This guy, how do you know so much?

In the Egyptian camel team, Mugalen looked at his mobile phone while riding a camel, with a constipated expression on his face.

Is this something people should know?

Bi Fang rummaged through his backpack and counted the supplies.

The water resources are still sufficient, and there are a few desert gourds hanging on the camel as a supplement. It can last at least five days, but the food is not enough, and there are still a few small pieces of dried fish.

The previous food was basically left over after catching some fish in the second half of crossing Nemo point, and it was almost eaten after a few days.

Looking up and looking around, the original Gobi has completely turned into a vast desert.

Pulling out a piece of dried fish, Bi Fang stuffed it into his mouth and chewed dryly, watching the sun gradually slanting towards the west.

Need to build a shelter, until tomorrow, we need to go find some food.