Three thousand years ago, dense old-growth rainforests covered most of central Africa. But around 2,600 years ago, an event that ecologists call the Late Holocene Rainforest Crisis occurred, and the forests suddenly gave way to savannas dotted with islands of trees. Six hundred years later, the forests grew back almost as swiftly as they had vanished. But for the last 20 years, paleoecologists have debated what caused the Rainforest Crisis.
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The currently accepted version among paleoecologists is that warming sea-surface temperatures in the Gulf of Guinea caused a shift in the region’s monsoon cycle, leading to a longer, drier dry season, so people migrated south to farm millet on the open grasslands. But University of Potsdam paleoecologist Yannick Garcin and his colleagues, who just published a new study on the Rainforest Crisis, argue that it happened the other way around: people moved south into the rainforest and cleared land to plant millet. And when their population crashed 600 years later, the rainforest rebounded.
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One thing scientists on all sides agree on is that it’s important to understand the cause of past events like this, because reconstructing past climate events can help predict how humans, climate, and vulnerable ecosystems might interact in the future. And in some ways, the Rainforest Crisis is an encouraging story, because it means the rainforest can bounce back from deforestation.
Read full, original post: African rainforests vanished for 600 years, then bounced back—why?
