|
This desertification was probably initiated by subtle changes in the earth's orbit, and amplified by atmospheric and vegetation feedback. The desertification of the Sahara appears to have occurred simultaneously with the domestication of cattle, the pack ass, and a small screw horned goat, and other grazing animals.3.3 Combining overgrazing with deforestation for firewood, as well as slash and burn agricultural practices, contributed to the atmospheric and vegetation feedback which today results in giant Sahara sand storms (see Figure 38a and 38b). These storms carry dust as far as the Caribbean, where the dust particles clog up and introduce foreign bacteria and fungi, which combine to kill coral reefs, removing a major CO2 sequestration site, and affecting global warming across the 5,500 years of desertification of the Sahara. This one ancient example certainly demonstrating mankind forms an important class of actors on the Earth's stage.
 |
|  |
Figure 39a. Saharan Dust over the Atlantic.3.4 These dust storms take about 5 to 7 days to cross the Atlantic Ocean. |
| Figure 39b. Saharan Dust over the Mediterranean.3.5 The patch of green on the right is what is left of ancient vegetation which covered the Sahara after the last Ice Age. |
|
paradoxes
