Is Global Warming Really Harming Africa's Sahel Region?
Dubious Warmist "science" again
Global warming activists are sounding four-alarm fire bells over a new study claiming global warming is causing drought and killing trees in the Sahel region of sub-Saharan Africa. Much like previous claims that have fallen by the wayside, the notion that global warming is devastating the Sahel is unlikely to stand the dual tests of time and scientific scrutiny.
According to the new study, a rise in temperatures and a decline in precipitation during the 20th century reduced tree densities in the Sahel by approximately 18 percent from 1954 through 2002. Lead author Patrick Gonzalez says in a press release accompanying the study, "Rainfall in the Sahel has dropped 20-30 percent in the 20th century."
Lead author Gonzalez is also a lead author for the United Nations Intergovernmental Panel on Climate Change (IPCC), whose funding and very existence are dependent on the assertion that humans are causing a global warming crisis. Moreover, IPCC is on record claiming global warming is causing an increase in drought, so having a new study claiming global warming is causing drought and related problems in Africa's Sahel region bolsters the shared interests of Gonzalez and IPCC.
Turning to the science, assertions that global warming is causing drought and tree deaths in the Sahel is surprising news to many scientists and Sahel observers. The Sahel is a relatively narrow band of land stretching east-west across the African continent at the southern edge of the Sahara Desert. Contrary to what Gonzalez reports in his new study, many studies have documented improving conditions in the Sahel as the earth has warmed.
"The southern Saharan desert is in retreat, making farming viable again in what were some of the most arid parts of Africa," New Scientist reported in 2002. "Burkina Faso, one of the West African countries devastated by drought and advancing deserts 20 years ago, is growing so much greener that families who fled to wetter coastal regions are starting to go home."
An "analysis of satellite images completed this summer reveals that dunes are retreating right across the Sahel region on the southern edge of the Sahara desert," New Scientist explained. "Vegetation is ousting sand across a swathe of land stretching from Mauritania on the shores of the Atlantic to Eritrea 6000 kilometres away on the Red Sea coast. Nor is it just a short-term trend. Analysts say the gradual greening has been happening since the mid-1980s."
"There are more trees for firewood and more grassland for livestock. And a survey among farmers shows a 70 per cent increase in yields of local cereals such as sorghum and millet in one province in recent years," New Scientist added.
These trends have continued throughout the past decade. In 2009 scientists at Boston University used satellite data to study African vegetation patterns since the mid-1990s. As reported by BBC News, "satellite images from the last 15 years do seem to show a recovery of vegetation in the Southern Sahara."
"The broader picture is reinforced by studies carried out in the Namib Desert in Namibia," BBC News added. "This is a region with an average rainfall of just 12 millimetres per year - what scientists call `hyper-arid'. Scientists have been measuring rainfall here for the last 60 years. Last year the local research centre, called Gobabeb, measured 80mm of rain."
Scientists at Brown University and the University of Minnesota-Duluth confirmed a longer term improvement in African soil moisture. After studying African drought patterns since the 1400s, the scientists reported in January 2007 in the peer-reviewed science journal Geology that Africa is "experiencing an unusually prolonged period of stable, wet conditions in comparison to previous centuries of the past millennium."
Moreover, "the patterns and variability of twentieth-century rainfall in central Africa have been unusually conducive to human welfare in the context of the past 1400 yr," the scientists explained.
The same patterns are occurring globally. Analyzing satellite imagery that has been available since 1982, scientists reported in a 2003 peer-reviewed study in Science, "We present a global investigation of vegetation responses to climatic changes by analyzing 18 years (1982 to 1999) of both climatic data and satellite observations of vegetation activity. Our results indicate that global changes in climate have eased several critical climatic constraints to plant growth, such that net primary production increased 6% (3.4 petagrams of carbon over 18 years) globally."
With so many studies and data indicating global warming is benefiting soil moisture, plant growth and forest expansion in the Sahel region, Africa as a whole and globally, the new assertion that global warming is causing a climate crisis in the Sahel is speculative and controversial at best.