4 ms·

1. The whole Sahara + mideast was a lot greener a few thousand years ago due to ice ages et al, not due to soil depletion https://en.wikipedia.org/wiki/African_

1. The whole Sahara + mideast was a lot greener a few thousand years ago due to ice ages et al, not due to soil depletion https://en.wikipedia.org/wiki/African_humid_period https://en.wikipedia.org/wiki/African_humid_period 2. The Euphrates floodplain is still quite green, like the Nile's. It's not like the US midwest where you have thousands of square miles of grass, but you do have a strip of extremely reliably fertile land (and for civilization-building, reliable seasons are super important).

ncmncm 5y ago
Until 8000 years ago most of the present Persian Gulf was fertile valley. It is a good bet that archaeological sites critically important to understanding the rise of civilization are under it now. Deforestation is a common cause of desertification worldwide. Trees help to capture moisture from the air and bring it to ground. Cut them down, and the moist air blows past. Trees are commonly cleared for farmland, and then the farmland has to be abandoned when it gets too dry. In the Amazon basin and along the northwest coast of North America, trees were the basis of productive agriculture, carefully chosen mixes of trees of different sizes and species. To this day the Amazon basin is dominated by tree species that were once cultivated throughout, supporting tens of millions until they were wiped out by smallpox and other pandemics. In North America, such tree gardens can still be found centuries after they were abandoned.
- hulitu 5y ago
  > Deforestation is a common cause of desertification worldwide. Trees help to capture moisture from the air and bring it to ground. Cut them down, and the moist air blows past. Trees are commonly cleared for farmland, and then the farmland has to be abandoned when it gets too dry. Trees alone do not help. There are a lot of tree farms which do not capture moisture and are prone to forest fires. We need forests with good ecosystems not tree plantations.
  - ncmncm 5y ago
    Planting trees (particularly the wrong ones) might not help much, but cutting down trees seems to reliably do harm.

ncmncm 5y ago

Until 8000 years ago most of the present Persian Gulf was fertile valley. It is a good bet that archaeological sites critically important to understanding the rise of civilization are under it now. Deforestation is a common cause of desertification worldwide. Trees help to capture moisture from the air and bring it to ground. Cut them down, and the moist air blows past. Trees are commonly cleared for farmland, and then the farmland has to be abandoned when it gets too dry. In the Amazon basin and along the northwest coast of North America, trees were the basis of productive agriculture, carefully chosen mixes of trees of different sizes and species. To this day the Amazon basin is dominated by tree species that were once cultivated throughout, supporting tens of millions until they were wiped out by smallpox and other pandemics. In North America, such tree gardens can still be found centuries after they were abandoned.

hulitu 5y ago
> Deforestation is a common cause of desertification worldwide. Trees help to capture moisture from the air and bring it to ground. Cut them down, and the moist air blows past. Trees are commonly cleared for farmland, and then the farmland has to be abandoned when it gets too dry. Trees alone do not help. There are a lot of tree farms which do not capture moisture and are prone to forest fires. We need forests with good ecosystems not tree plantations.
- ncmncm 5y ago
  Planting trees (particularly the wrong ones) might not help much, but cutting down trees seems to reliably do harm.