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Originally Posted by Ladogaboy
Goats made it stop raining? As it is, the dry cycle for the Sahara seems to be ending, and it might well be turning back into a savannah within our (at least, my) lifetime.
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Yes, it's primarily down to goats, rather than climate cycles. Start with an arid grassland, similar to the remmnant of the prairies of North America. They're composed of grasses & other deep-rooted plants, which form a sod which conserves water, so that the community is able to subsist on little rainfall. Break down that sod, by overgrazing (or by plowing, as in the US "Dust Bowl"), and it shifts to dry dirt. Even if the overgrazing is stopped, the former plant community has a difficult time re-establishing itself, especially when every scrap of vegetation is pounced on by herders & their cattle.
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Our current, global climate isn't even as high as it was speculated to be during the Cretaceous Period.
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Yet. What you're forgetting there is the lag time. The Earth's a big place, and takes a long time (in human terms) to warm up. We haven't seen anywhere near the full warming that will happen due to past CO2 additions, and won't for decades yet.
As for the similarity to the P-T extinction, it's not the lava, which is pretty irrelevant (unless you happen to be under it, of course). It's the fact that the eruptions happened in a place where there were extensive coal beds, thus setting off a coal-burning episode similar to what humans are doing.