If the history books that I’ve read are correct, then during the time of Alexander the Great, the northern coast of Africa (outside of the areas with higher human population density) was a functioning dry-forest ecosystem. During the time of the Roman Empire, people cut down large areas of forest in order to plant grass – wheat and barley for human consumption, and pasture grass for cows and goats. Without sufficient forest cover to pull in moisture from the Mediterranean, the rains stopped coming, the remaining vegetation died off, and the Sahara Desert advanced to the coast. This was a case of human-caused climate change.

Forests precede civilisations, and deserts follow them.

Something to keep in mind the next time that you hear/read that non-forest ecosystems are “natural” and should be preserved as they are.

  • gandalf_der_12te@feddit.org
    22·
    4 days ago

    I’m pretty sure the sahara was a desert even before the romans, because there’s no rainfall and that’s what matters. A forest doesn’t just magically pull in moisture from hundreds of kilometers away.

    Anyways, you’re right. Humans shaped the landscape more than anything else in recent history. I calculated a few days ago that all of humanity has moved around 2*10¹⁶ kg of construction material around (this includes wood). If you divide that by the 400 million km² of Earth’s surface area, you arrive at 5 cm of soil surface layer that was transformed, which is essentially the most important part of the biosphere. Practically all of the forests (*with the exception of some high mountains) north of 30° N (and south of 55° N) have been cut down. Germany is all acre now, used to be all forest before the romans. Instead of 20 m high trees, we have 1 m high grains now.

    Anyways, it’s not all bad. First of all this allowed large amount of food to be produced, and who are we to say no to hungry children?

    Secondly, the land is not actually a desert. It can be sustainable as long as we harvest crops at a slow enough pace for the environment to be able to keep up with it, in other words if we only use 30% of the available crop space instead of 100%.