Nature & Environment
Scientist Investigate Africa's Abrupt Climate Shift from Humid to Dry
Catherine Griffin
First Posted: Feb 23, 2015 09:27 AM EST
Scientists are learning a bit more about abrupt climate shifts. They examined African lake sediments from the past 20,000 years in order to advance their understanding of current changing weather patterns and what we might expect in the future.
In order to better understand past climate shifts, the researchers analyzed core samples from Lake Bosumtwi, which was formed by a meteor and sits like a bowl on the landscape. The scientists drilled 1,000 feet to the lake's bottom and another 1,000 feet into the meteor impact structure. These sediments spanned one million years, though the scientists only focused on the past 20,000 years.
"We saw a complex response in climate changes, not this uniform picture with all of Africa doing the same thing," said Nicholas McKay, one of the researchers, in a news release.
Africa changed from a humid environment to a more arid region. Humid conditions actually remained until about 3,000 years ago, providing supportive habitats for humans, animals and plants. The researchers studied the isotopes in the lake sediments in order to understand monsoonal changes, as well. They found that the climate shift from humid to arid occurred much quicker than expected. IT's possible that anomalies were created by the reactions of soil moisture and plants to a diminishing monsoon.
"Rapidly, it went from no dust to lots of dust, instead of being a gradual transition from being wet to being dry," said McKay. "The plants do a good job of reinforcing their own existence by making it a little moisture and bringing more rain. But if you cross the moisture threshold where the plants die, then it also stops raining and it sorts of snowballs really fast and that is how you can get these really rapid changes."
The findings are published in the journal Nature Geoscience.
For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).
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First Posted: Feb 23, 2015 09:27 AM EST
Scientists are learning a bit more about abrupt climate shifts. They examined African lake sediments from the past 20,000 years in order to advance their understanding of current changing weather patterns and what we might expect in the future.
In order to better understand past climate shifts, the researchers analyzed core samples from Lake Bosumtwi, which was formed by a meteor and sits like a bowl on the landscape. The scientists drilled 1,000 feet to the lake's bottom and another 1,000 feet into the meteor impact structure. These sediments spanned one million years, though the scientists only focused on the past 20,000 years.
"We saw a complex response in climate changes, not this uniform picture with all of Africa doing the same thing," said Nicholas McKay, one of the researchers, in a news release.
Africa changed from a humid environment to a more arid region. Humid conditions actually remained until about 3,000 years ago, providing supportive habitats for humans, animals and plants. The researchers studied the isotopes in the lake sediments in order to understand monsoonal changes, as well. They found that the climate shift from humid to arid occurred much quicker than expected. IT's possible that anomalies were created by the reactions of soil moisture and plants to a diminishing monsoon.
"Rapidly, it went from no dust to lots of dust, instead of being a gradual transition from being wet to being dry," said McKay. "The plants do a good job of reinforcing their own existence by making it a little moisture and bringing more rain. But if you cross the moisture threshold where the plants die, then it also stops raining and it sorts of snowballs really fast and that is how you can get these really rapid changes."
The findings are published in the journal Nature Geoscience.
For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone