Scientists believe that increased levels of greenhouse effect causing gases were the main reason behind huge amounts of rainfall in two African regions thousands of years ago. And they have reasons to believe that history might repeat itself, with modern day greenhouse emissions affecting the weather patterns and climate of the area in a similar fashion once again.
It was earlier believed that the orbit of the earth and the position of its axis were the main factors responsible for the abrupt weather changes in Africa about 14,700 years ago. The period known as the African Humid Period (AHP) lasted for more than 10,000 years.
A new study at the National Center for Atmospheric Research in Boulder, Colorado however suggest that the abrupt changes earlier were caused by greenhouse gases.
“The fact that the model gets it right and that we can explain it, that gives us confidence that the model can tell us about future patterns of rainfall in the region,” study author Bette Otto-Bliesner told Bloomberg News. “It was the rise of greenhouse gases, in particular carbon dioxide and methane, in the atmosphere that gave that region a common signal.”
“The future effect of greenhouse gases on rainfall in Africa is a critical socioeconomic issue. Africa’s climate seems destined to change, with far-reaching implications for water resources and agriculture,” he said.
Ever since the huge ice sheets over North America and northern Europe started melting, the African region started experiencing unusually heavy rainfall in tow regions- one to the north of the equator and the other to the south of it. The heavy rainfall ‘turned portions of Africa’s deserts into grasslands and savannas.’ What caused this AHP had baffled the scientific community for years.
This was the most recent instance of the combined effect of global warming and the concentration of greenhouse gases (especially carbon dioxide and methane) on our planet.
“This study is a step toward solving the puzzle of what triggered abrupt changes in rainfall over southeastern equatorial and northern Africa during early deglaciation,” said Anjuli Bamzai, program director in NSF’s Division of Atmospheric and Geospace Sciences, which funded the research.
There are already indications to believe that the climatic changes brought about due to human interference are causing an increase in the level of rainfall in the region once again. The fact has been corroborated by both ground measurements and satellite measurements. If the rainfall continues to increase in the same manner, some parts of this continent might have to deal with serious resource management issues.
“The future impact of greenhouse gases on rainfall in Africa is a critical socioeconomic issue,” Otto-Bliesner said in a press release. “Africa’s climate seems destined to change, with far-reaching implications for water resources and agriculture.”
The study was funded by the National Science Foundation (NSF), NCAR’s sponsor, and the U.S. Department of Energy’s Office of Science and its findings were first published in the journal Science.