News / Africa

    Did Early Man Contribute to Central Africa Climate Change?

    The Dzanga-Ndoki National Park and Dzanga-Sangha dense forest special reserve are located in the rainforest in the south-western part of the Central African Republic, Congo Basin. They comprise a total area of more than 4 000 km2 (more than 400 000 hectar
    The Dzanga-Ndoki National Park and Dzanga-Sangha dense forest special reserve are located in the rainforest in the south-western part of the Central African Republic, Congo Basin. They comprise a total area of more than 4 000 km2 (more than 400 000 hectar
    Joe DeCapua

    If humans are responsible for speeding the climate change currently underway, it may not be the first time. Scientists say a long time ago in Central Africa, early farmers may have contributed to the disappearance of rainforests. The question is being raised in the journal Science.

    Scientists say about 3,000 years ago some of the rainforests were “abruptly replaced” by savannas – broad grasslands dotted with shrubs and trees. It was thought that climate change was the reason. But now research suggests that climate change alone could not be responsible for the sudden shift -- that perhaps people played a part.

    Dr. Germain Bayon, who works for a French research institute, said much less is known about the agricultural history of Africa than either Europe or Asia.

    “The onset of agriculture had already an impact on the environment, whereas in Africa, I guess because there have been (a lot fewer ) studies done, the link was not very clear,” he said.

    Telltale mud

    Bayon and his colleagues have been studying sediment at the mouth of the Congo River.

    “Basically, we analyzed the sediment core, which was recovered off the Congo River. Sediments have been accumulating at this site… which provide an integrated record of the particles, which have been discharged by the Congo River through time,” he said.

    The sediment tells the story of the Congo Basin climate.

    “The climate in Central Africa was much more humid between about 10,000 years ago and 5,000 years ago. And then the climate started to deteriorate. So, it’s only after about 4,000 years ago that the climate started to become dryer and of course the vegetation responded to this climate change,” said Bayon.

    That’s when the savannahs started to appear. But Bayon said there may be other major contributing factors, such as erosion and the chemical weathering of soil.

    “So, basically, the more it rains in Africa, the more the soils were being eroded. And what we showed is that from 3,000 years ago the weathering erosion signal became completely decoupled from the climatic signal. And this we think is a sign that this event was not only triggered by a change in the climate. And we need to take something else into account,” he said.

    Migration of the Bantu

    Enter the Bantu people from what is now the border area between Nigeria and Cameroon. Bayon said they brought farming and iron smelting to the Congo Basin. Evidence shows one of the main crops was pearl millet. And that in itself says a lot about the climate.

    “Pearl millet to be cultivated actually doesn’t like the warm climate, humid climate. It requires alternating between a dry season and a wet season. It shows that the key factor for introducing agriculture into the rainforest was the establishment of this more pronounced seasonality. This alternates between wet and dry seasons,” he said.

    To grow pearl millet and other crops, the Bantu needed open fields. That meant clearing large areas of rainforest. That in turn exposed the land to erosion and resulted in the telltale sediment at the mouth of the Congo River. So, it’s possible, said Bayon, the farmers along with climate change helped the rainforests to disappear.

    The period lasted between 1,000 and 1500 years. Then things started to change again. The rainforests began to return. About the same time, the Bantu left for other parts of Africa. The question is: did the Bantu leave because the rainforests started to regrow or did the rainforests regrow because the Bantu left and took their farming with them?

    “This, I must admit,” said Bayon, “is something which is a bit puzzling and which is not well known at present, I think.”

    Bayon said, however, what the evidence does show is that even 3,000 years ago humans could have a major impact on the environment. It’s now known that agriculture contributes to carbon emissions and that trees help trap that carbon and keep it from the atmosphere. During the Bantu’s stay in Central Africa, there was more agriculture and fewer trees.

    You May Like

    Turkey, US Splits Deepen Over Support for Kurdish Militants

    Ankara summons American ambassador to protest remarks by State Department spokesman who said Washington does not consider Syria's Kurdish Democracy Union Party (PYD) a terrorist organization

    Obama Seeking $19 Billion for National Cybersecurity

    Move, touted as attempt to build broad, cohesive federal response to cyberthreats, calls for increase in cybersecurity spending across all government agencies

    Video Foreign Policy Weighs Heavy for Some US Voters

    VOA talks to protesters in Manchester, New Hampshire, who sound off on foreign policy issues such as the Guantanamo Bay prison, the Israeli-Palestinian conflict and the wars in Iraq, Syria and Yemen

    This forum has been closed.
    Comments
         
    There are no comments in this forum. Be first and add one

    By the Numbers

    Featured Videos

    Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
    Valentine's Day Stinks for Lebanese Clownsi
    X
    February 09, 2016 8:04 PM
    This weekend, on Valentine's Day in Lebanon, love is not the only thing in the air. More than half a year after the country's trash crisis began, the stink of uncollected garbage remains on the streets. Step forward "Clown Me In," a group of clowns who use their skills for activism. Before the most romantic day of the year the clowns have released their unusual take on love in Lebanon -- in a bid to keep the pressure up and get the trash off the streets. John Owens reports from Beirut.
    Video

    Video Valentine's Day Stinks for Lebanese Clowns

    This weekend, on Valentine's Day in Lebanon, love is not the only thing in the air. More than half a year after the country's trash crisis began, the stink of uncollected garbage remains on the streets. Step forward "Clown Me In," a group of clowns who use their skills for activism. Before the most romantic day of the year the clowns have released their unusual take on love in Lebanon -- in a bid to keep the pressure up and get the trash off the streets. John Owens reports from Beirut.
    Video

    Video Rocky Year Ahead for Nigeria Amid Oil Price Crash

    The global fall in the price of oil has rattled the economies of many petroleum exporters, and Africa’s oil king Nigeria is no exception. As Chris Stein reports from Lagos, analysts are predicting a rough year ahead for the continent’s top producer of crude.
    Video

    Video Foreign Policy Weighs Heavy for Some US Voters

    VOA talks to protesters in Manchester, New Hampshire who sound off on foreign policy issues such as the Guantanamo Bay Prison, the Israeli-Palestinian conflict, Middle East Affairs and national security.
    Video

    Video 'No Means No' Program Targets Sexual Violence in Kenya

    The organizers of an initiative to reduce and stop rape in the informal settlements around Kenya's capital say their program is having marked success. Girls are taking self-defense classes while the boys are learning how to protect the girls and respect them. Lenny Ruvaga reports from Nairobi.
    Video

    Video New Hampshire Voters Are Independent, Mindful of History

    Once every four years, the northeastern state of New Hampshire becomes the center of the U.S. political universe with its first-in-the-nation presidential primary. What's unusual about New Hampshire is how seriously the voters take their role and the responsibility of being among the first to weigh in on the candidates.
    Video

    Video Chocolate Lovers Get a Sweet History Lesson

    Observed in many countries around the world, Valentine’s Day is sometimes celebrated with chocolate festivals. But at a festival near Washington, the visitors experience a bit more than a sugar rush. They go on a sweet journey through history. VOA’s June Soh takes us to the festival.
    Video

    Video 'Smart' Bandages Could Heal Wounds More Quickly

    Simple bandages are usually seen as the first line of attack in healing small to moderate wounds and burns. But scientists say new synthetic materials with embedded microsensors could turn bandages into a much more valuable tool for emergency physicians. VOA’s George Putic reports.
    Video

    Video Bhutanese Refugees in New Hampshire Closely Watching Primary Election

    They fled their country and lived in refugee camps in neighboring Nepal for decades before being resettled in the northeastern U.S. state of New Hampshire -- now the focus of the U.S. presidential contest. VOA correspondent Aru Pande spoke with members of the Bhutanese community, including new American citizens, about the campaign and the strong anti-immigrant rhetoric of some of the candidates.
    Video

    Video Researchers Use 3-D Printer to Produce Transplantable Body Parts

    Human organ transplants have become fairly common around the world in the past few decades. Researchers at various universities are coordinating their efforts to find solutions -- including teams at the University of Pennsylvania and Rice University in Houston that are experimenting with a 3-D printer -- to make blood vessels and other structures for implant. As VOA’s Greg Flakus reports from Houston, they are also using these artificial body parts to seek ways of defeating cancerous tumors.
    Video

    Video Helping the Blind 'See' Great Art

    There are 285 million blind and visually impaired people in the world who are unable to enjoy visual art at a museum. One New York photographer is trying to fix this situation by making tangible copies of the world’s masterpieces. VOA correspondent Victoria Kupchinetsky was there as visually impaired people got a feel for great art. Joy Wagner narrates her report.
    Video

    Video German Artists to Memorialize Refugees With Life Jacket Exhibit

    Sold in every kind of shop in some Turkish port towns, life jackets have become a symbol of the refugee crisis that brought a million people to Europe in 2015.  On the shores of Lesbos, Greece, German artists collect discarded life jackets as they prepare an art installation they plan to display in Germany.  For VOA, Hamada Elrasam has this report from Lesbos, Greece.
    Video

    Video E-readers Help Ease Africa's Book Shortage

    Millions of people in Africa can't read, and there's a chronic shortage of books. A non-profit organization called Worldreader is trying to help change all that one e-reader at a time. VOA’s Deborah Block tells us about a girls' school in Nairobi, Kenya where Worldreader is making a difference.
    Video

    Video Genius Lets World Share Its Knowledge

    Inspired by crowdsourcing companies like Wikipedia, Genius allows anyone to edit anything on the web, using its web annotation tool
    Video

    Video In Philippines, Mixed Feelings About Greater US Military Presence

    In the Philippines, some who will be directly affected by a recent Supreme Court decision clearing the way for more United States troop visits are having mixed reactions.  The increased rotations come at a time when the Philippines is trying to build up its military in the face of growing maritime assertiveness from China.  From Bahile, Palawan on the coast of the South China Sea, Simone Orendain has this story.