Ethiopia had higher rainfall, warmer soil, millions of years ago

From a Southern Methodist University press release

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Ethiopia 27 million years ago had higher rainfall, warmer soil

Thirty million years ago, before Ethiopia’s mountainous highlands split and the Great Rift Valley formed, the tropical zone had warmer soil temperatures, higher rainfall and different atmospheric circulation patterns than it does today, according to new research of fossil soils found in the central African nation.

Neil J. Tabor, associate professor of Earth Sciences at SMU and an expert in sedimentology and isotope geochemistry, calculated past climate using oxygen and hydrogen isotopes in minerals from fossil soils discovered in the highlands of northwest Ethiopia. The highlands represent the bulk of the mountains on the African continent.

tabor_lg.jpgTabor’s research supplies a picture of the paleo landscape of Ethiopia that wasn’t previously known because the fossil record for the tropics has not been well established. The fossils were discovered in the grass-covered agricultural region known as Chilga, which was a forest in prehistoric times. Tabor’s research looked at soil fossils dating from 26.7 million to 32 million years ago.

Fossil plants and vertebrates in the Chilga Beds date from 26.7 million to 28.1 million years ago, Tabor says. From his examination, Tabor determined there was a lower and older layer of coal and underclay that was a poorly drained, swampy landscape dissected by well-drained Oxisol-forming uplands. A younger upper layer of the Chilga Beds consists of mudstones and sandstones in what was an open landscape dominated by braided, meandering fluvial stream systems.

Tabor is part of a multi-disciplinary team combining independent lines of evidence from various fossil and geochemical sources to reconstruct the prehistoric climate, landscape and ecosystems of Ethiopia, as well as Africa.

The project is funded with a three-year, $322,000 grant from the National Science Foundation. The team includes paleoanthropologists, paleobotanists and vertebrate paleontologists from the University of Texas at Austin, Miami University, Southern Methodist University, the Fort Worth Museum of Science and History, Washington University and the University of Michigan.

Tabor presented the research in a topical session at the Oct. 18-21 annual meeting of the Geological Society of America. The presentation was titled “Paleoenvironments of Upper Oligocene Strata, NW Ethiopian Plateau.” His co-researcher is John W. Kappelman, Department of Anthropology, University of Texas. — Margaret Allen

17 thoughts on “Ethiopia had higher rainfall, warmer soil, millions of years ago

  1. Having spent my formative years living in Asmara Eritrea, formerly a provence of Ethiopia, I had much opportunity to travel throughout the Eritrean Highlands and Great Rift Valley escarpment. Living at 2,400m (7,600 ft) AMSL, we enjoyed mild days with pleasantly cool evenings. Air conditioning was not required.
    An interesting trait of the culture is most Ethiopians are black caucasians, having dark skin with caucasian features, tracing direct roots back to the Jewish Tribe of Judah – truly beautiful people.
    What stands out in my memory regarding the climate were the rain and hail storms. Imagine one or two inches of hail on the ground following a heavy downpour (or what ever you call it for hail). While Ethiopia was wetter 27 million years ago, it isn’t terribly dry in modern times (avg. .8 to 2.2 meters precipitation per year).

  2. “Hank Hancock (16:28:38) :
    An interesting trait of the culture is most Ethiopians are black caucasians, having dark skin with caucasian features, tracing direct roots back to the Jewish Tribe of Judah – truly beautiful people.”
    Totally agree with that. My wife is Ethiopian, and I married her three times LOL in Ethiopia.
    It is a wonderful country.

  3. The problem of droughts is most likely not related to AGW, but does have an anthropogenic genesis. For one instance, think of the hydro-cycle and evaporation in particular. What percentage of water do you think is trapped in pipes, unavailable for evaporation and the consequent condensation needed to provide rainfall and forestall a drought? Diverted from its usual gathering place to farms? Sitting in toilets? Sitting in bottles? And so on the list goes. It is really ignorant to think that all of this has no influence. After these influences are removed, one can speculate on climate change as a cause, not before.

  4. “Thirty million years ago, before Ethiopia’s mountainous highlands split and the Great Rift Valley formed, the tropical zone had warmer soil temperatures, higher rainfall and different atmospheric circulation patterns than it does today, […]”
    Thirty million years ago the climate was different… and this is news?!?! Climate changes. Get used to it already. [/anti-AGW scoffing]
    It ~is~ interesting to learn about how our planet’s geography and climate have changed over time. In the perspective of 30 million years, ice ages are weather, not climate.

  5. David (18:04:10) :
    . . . What percentage of water do you think is trapped in pipes, unavailable for evaporation and the consequent condensation needed to provide rainfall and forestall a drought? Diverted from its usual gathering place to farms? Sitting in toilets? Sitting in bottles? And so on the list goes. It is really ignorant to think that all of this has no influence. After these influences are removed, one can speculate on climate change as a cause, not before.

    Interesting speculation, but is it any more than that? Has anyone ever tried to estimate the amount of water sequestered in pipes, toilets, and bottles? My guess (it is nothing more) is that it would be trivial, compared to the flow of rain and rivers and lakes and aquifers. There’s an awful lot of water that goes over the dam just down the street from us, and that’s only one fairly minor river. . .
    And the toilets get emptied and refilled fairly often.
    /Mr Lynn

  6. Patrick Davis: I cannot speak to the origin of the Ethiopians. McEvedy refers to them as “Nilo-Saharan”. They were bypassed by the Bantu-speaker migrations, which went eastward (eventually across to the south of Ethiopia) and then turned south.

  7. I forgot to mention “Lucy” was found in Ethiopia and is in the national museum in Addis Ababa. Most Ethiopians accept “Lucy” to be our evolutionalry ancestor, but also believe God created all life.

  8. I would think that 30 million years ago the region of Chilga was in the equatorial rain belt and has since moved northwards because of continental drift. (The paleo-ocean of Tethys existed then between Africa and Europe and the Alps formed because of the collision of the two plates.)
    During the Carboniferous period, 300 to 350 million years ago, the UK area was in the equatorial rain forest region and rocks of this age rich in coal – hence the name: the Carboniferous period.

  9. Ethiopians are lovely people, with a long, complex history and who deserve better than they got, both climatologically and historically.

  10. The ITCZ (Inter Tropical Convergence Zone) is further south than it normally is. If it was further north it would mean global warming. This affects Ethiopian weather. Italian climatologists have written the following (translation by Imtranslator):
    During the period between the first and ten of October 2009 the African side of the intertropical front (ITF) was located at about 14.1 degrees north latitude, while the normal position for the period is 14.1 degrees north latitude. L ‘ITF is returned to below its normal value, abnormality that has been for much of the season. Fig.1 shows the current position compared with the normal one, and it is clear from this diagram that the ‘ITF is below its normal value throughout the African continent. Comparing the current position with that of the 1978-2008 historical average, the historical average is 14 degrees north latitude in the east, while the current position is 12.9 degrees north latitude. While in the western part of the front is the position at 14.9 degrees latitude north, slightly south of its normal position of 15.8 degrees north latitude. Figures 2 and 3 show the peak now reached the front in 2009, and its average returns in this last decade.

  11. Sorry, link didn’t work before
    The ITCZ (Inter Tropical Convergence Zone) is further south than it normally is. If it was further north it would mean global warming. This affects Ethiopian weather. Italian climatologists at
    http://www.meteoscienze.it/itcz/261-itcz-prima-decade-di-ottobre-nella-norma
    have written the following (translation by Imtranslator):
    During the period between the first and ten of October 2009 the African side of the intertropical front (ITF) was located at about 14.1 degrees north latitude, while the normal position for the period is 14.1 degrees north latitude. L ‘ITF is returned to below its normal value, abnormality that has been for much of the season. Fig.1 shows the current position compared with the normal one, and it is clear from this diagram that the ‘ITF is below its normal value throughout the African continent. Comparing the current position with that of the 1978-2008 historical average, the historical average is 14 degrees north latitude in the east, while the current position is 12.9 degrees north latitude. While in the western part of the front is the position at 14.9 degrees latitude north, slightly south of its normal position of 15.8 degrees north latitude. Figures 2 and 3 show the peak now reached the front in 2009, and its average returns in this last decade.

  12. Well, the climate did change in what is now Ethiopia sometime before about 4.5million years ago. That’s one reason why “Lucy” was found where she was found, and how her skeletal remains were the way they were too.

  13. .
    There is no drought in Ethiopia – no more than usual anyway – their problem is a tripling of population inside a generation, from 25 million to nearly 75 million. This is unsustainable, and any Green should know but steadfastly refuses to acknowledge.
    The Irish had the same problem in the 1840s, with the Great Potato Famine. The Irish do so love to blame the English (British) for this disaster, but a quick look at the demographics will demonstrate an eight-fold increase in population inside two generations. It was a disaster waiting to happen.
    http://en.wikipedia.org/wiki/File:IrelandEuropePopulation1750.PNG
    The Irish solved their problem by exporting their overpopulation to America, but in today’s world, exporting an overpopulated Ethiopia to an already overcrowded West is NOT an answer.
    .

  14. What percentage of water do you think is trapped in pipes…

    I think some percentage of people are trapped in cities and need to get out of town more often. There aren’t many pipes in that modern farmland 50 miles away from your home, and even if it’s covered by irrigation sprinklers that only happens where water is cheap enough for such irrigation.
    Go take a look at the infrastructure of Ethiopia. How many homes in villages have any pipes? Browse the satellite maps, do you see any irrigation circles?
    While you’re on the satellite maps, look at the lakes trapped by the rift. Why is there water there? Do you know what happens when moist air meets mountains?

  15. “ralph (11:17:39) :
    There is no drought in Ethiopia – no more than usual anyway”
    This is true however, and is actually quite fertile.
    ” – their problem is a tripling of population inside a generation, from 25 million to nearly 75 million.”
    True however, traditional farming practices hamper production and poor infrastructure (Although some roads in Ethiopia are better than some parts of major highways in Australia and New Zealand believe it or not) hamper distribution. Farming practices are changing (Thanks to LiveAid and other initiatives), like water storage, irrigation, crop rotation etc etc.
    “The Irish had the same problem in the 1840s, with the Great Potato Famine. The Irish do so love to blame the English (British) for this disaster, but a quick look at the demographics will demonstrate an eight-fold increase in population inside two generations.”
    Well it *was* the British who expelled Irish landlords, installed British, or sympathetic “landlords”, drove the Irish off their land etc etc.
    “It was a disaster waiting to happen.”
    It sure was.
    “ralph (11:29:01) :
    >>>Most Ethiopians accept “Lucy” to be our evolutionalry
    >>>ancestor, but also believe God created all life.
    Does that include onchocerca volvulus, the parasite that causes blindness?
    http://en.wikipedia.org/wiki/Onchocerciasis
    Your god must have a funny sense of humour. ;-)”
    It’s not my God, it’s their God, and yes, that is their beleif. That is one reason why, even in the face of abject poverty, filth and hunger, you see happy people. Visiting Ethiopia was a mind and eye opening experience which every “westerner” should have.
    There is some quite intereting geology there, Grand Canyon like sites, volcanos, hot springs etc etc…

  16. Patrick Davis (18:03:07) :
    “Totally agree with that. My wife is Ethiopian, and I married her three times LOL in Ethiopia.
    It is a wonderful country.”
    Agreed. The women are strikingly beautiful. I’ve been to most major cities in Ethiopia as well as Axum, one of their religious centers. One major contrast I see in comparison to other African countries is most Ethiopian cities are clean and full of gardens.
    ralph (11:29:01) :
    “Does that include onchocerca volvulus, the parasite that causes blindness?
    http://en.wikipedia.org/wiki/Onchocerciasis
    Your god must have a funny sense of humour. ;-)”
    I see no evidence of humor or even an argument as to why or why not they hold such a solid belief in their God. As Patrick Davis knowledgeably points out and which I too have witnessed, they are indeed a happy people. I doubt your convincing them of an imperfect or non-existent God would do anything for their culture other than lower their standards of living and destroy their identity as a people. Sad really that we puff ourselves up.

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