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Earth report: Down to Earth


Title Earth report: Down to Earth
Director(s) Tv/e Inspiring Change
Date released 2009
Production company Tv/e Inspiring Change
Length 22 MINS
Location West Africa
Keywords/tags Agriculture, food, desertification,   climate change
Link to film
Synopsis In West Africa, farmers are working to turn desert back to productive   farmland. Earth Report discovers how they could also have an important role   in the battle against climate change.
Reviews/discussion MIT Research Highlights for   background to this film:

Deforestation, Desertification, and the Drought in West Africa

The region of West Africa has experienced   significant changes in land cover during this century, ranging from   deforestation near the Atlantic coast to desertification near the border with   the Sahara desert.

Satellite image of vegetation types in Africa

The same region has been experiencing a   significant drought during the last few decades, with below normal levels of   rainfall observed almost everywhere within West Africa. This drought has been   associated with weakening of the monsoon circulation.

Ranifall Fluctuations in West Africa (1901-1990), expressed as
regionally averaged standardized departures, Nicholson (1993)

Eltahir and Gong (1996) proposed a general framework for   describing the role of biosphere-atmosphere-ocean interactions. It emphasizes   the role of the gradient in boundary layer moist static energy (entropy)   between ocean and land in modulating the dynamics of the monsoon.

A schematic of the proposed land-atmosphere-ocean interaction in
West Africa.

Zheng and Eltahir (1997) studied the response of the monsoon system   to deforestation and desertification using a simple model. The results   suggest that the potential impact of human induced change of land cover on   regional climate depends critically on the location of the change in   vegetation cover. That is, desertification along the border withthe Sahara   (e.g., in Chad, Niger, Mali and Mauritania) leaves a relatively minor impact   on monsoon circulation and regional rainfall; deforestation along the   southern coast of West Africa (e.g., in Nigeria, Ghana and Ivory Coast) may   result in complete collapse of monsoon circulation, and a significant   reduction of regional rainfall.

The meridional distribution of (a) total rainfall in mm/day, for
the control (solid line), desertifcation (dashed line), and deforestation
(dotted line); (b) same as (a) but for large-scale moisture convergence.

Source:   MIT Research highlights-


Links to other resources Also   see:

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