by Staff Writers
Bangui, Central African Republic (UPI) Feb 10, 2012
Present-day humans may not be the first to have affected world climate, researchers say, citing possible changes in Africa triggered by farmers 3,000 years ago.
French geochemist Germain Bayon, writing in the journal Science, says early farmers in Central Africa may have contributed to the disappearance of rainforests that were "abruptly" replaced by savannas, broad grasslands dotted with shrubs and trees.
Bayon and his colleagues studied weathering of sediment samples drawn from the mouth of the Congo River. Because deforestation would intensify weathering, the samples are a record of the climate for the past 40,000 years.
Between 20,000 and 3,500 years ago the samples showed weathering consistent with patterns of rainfall in the region, but around 3,000 years ago, "there was a complete decoupling" between rainfall and the rate of weathering, Bayon said.
The findings show "climate could not be the only factor in explaining deforestation," he said.
Bayon suggests Bantu-speaking peoples from what is now the border area between Nigeria and Cameroon moved into the Congo Basin around 4,000 years ago and had "a significant impact on the rainforest" as they cleared land for farming and iron-smelting.
That could have had a major impact on the environment, Bayon said, since it's now understood that agriculture contributes to carbon emissions and that trees help trap that carbon and keep it from the atmosphere, and during the Bantu's stay in Central Africa there was more agriculture and fewer trees.
Bayon said the study shows how the combination of culture and climate can affect the environment.
"Humans can have a huge impact on natural processes," he said.
Climate Science News - Modeling, Mitigation Adaptation
Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.
2C warming goal now 'optimistic' - French scientists
Paris (AFP) Feb 9, 2012
French scientists unveiling new estimates for global warming said on Thursday the 2 C (3.6 F) goal enshrined by the United Nations was "the most optimistic" scenario left for greenhouse-gas emissions. The estimates, compiled by five scientific institutes, will be handed to the UN's Intergovernmental Panel on Climate Change (IPCC) for consideration in its next big overview on global warming a ... read more
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2012 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement|