Comments on: Perspective on the Millennium Ecosystem Assessment http://rs.resalliance.org/2006/02/03/perspective-on-the-millennium-ecosystem-assessment/ coping with ecological suprise in a human dominated world Thu, 16 Oct 2008 00:22:16 +0000 http://wordpress.org/?v=2.5.1 By: Garry Peterson http://rs.resalliance.org/2006/02/03/perspective-on-the-millennium-ecosystem-assessment/#comment-166 Garry Peterson Wed, 08 Mar 2006 03:22:17 +0000 http://blog.resalliance.org/?p=126#comment-166 The Sahel's greening over the past decade, due to increased rainfall over the past decade is not inconsistent with a rainfall decline over the past 30 years. More about the connection between the Sahel, greening and climate can be found in the following paper. Wang, G., and E. A. B. Eltahir, 2000: Ecosystem dynamics and the Sahel drought. Geophys. Res. Lett., 27, 795–798. An overview of the Sahel's complex climate/veg dyanmics can be found in: Scheffer, M., S. R. Carpenter, J.A. Foley, C. Folke & B. Walker (2001) 'Catastrophic Shifts in Ecosystems'. Nature vol. 413 591-696. An up to date synthesis the social-ecological dimensions of desertification is presented in: Reynolds, J. F. & Stafford Smith, D. M. (2002) Global Desertification: Do Humans Cause Deserts? (Dahlem Univ. Press, Berlin). I took a quick look in the MA to see what they said and I find Theo Richel's comment puzzling as the MA does discuss the Sahel. I downloaded the Drylands chapter from Conditions and Trends and searched for Sahel - and found the MA states that there was little degredation in the Sahel despite statements in other assessments: "Recognizing the lack of adequate data on land degradation, the MA commissioned a desk study (Lepers 2003; Lepers et al. 2005) that compiled more-detailed (and sometimes overlapping) regional data sets derived from literature review, erosion models, field assessments, and remote sensing. This study found less alarming levels of land degradation (soil plus vegetation) in the drylands (including hyper-arid regions). Achieving only partial coverage, and in some areas relying on a single data set, it estimated that only 10% of global drylands were degraded. This includes 17% of drylands in Asia degraded, but in the Sahel region in Africa—an area reported as highly degraded by the Global Assessment (Oldeman et al. 1991) and by Dregne and Chou (1992)—few localities with degradation were found. The global number of people who live on lands determined by Lepers (2003) as degraded is about 20 million, much lower than the 117.5 million people living on lands defined as degraded by GLASOD."- (page 637, C&T) The Sahel’s greening over the past decade, due to increased rainfall over the past decade is not inconsistent with a rainfall decline over the past 30 years.

More about the connection between the Sahel, greening and climate can be found in the following paper.

Wang, G., and E. A. B. Eltahir, 2000: Ecosystem dynamics and the Sahel drought. Geophys. Res. Lett., 27, 795–798.

An overview of the Sahel’s complex climate/veg dyanmics can be found in:

Scheffer, M., S. R. Carpenter, J.A. Foley, C. Folke & B. Walker (2001) ‘Catastrophic Shifts in Ecosystems’. Nature vol. 413 591-696.

An up to date synthesis the social-ecological dimensions of desertification is presented in:

Reynolds, J. F. & Stafford Smith, D. M. (2002) Global Desertification: Do Humans Cause Deserts? (Dahlem Univ. Press, Berlin).

I took a quick look in the MA to see what they said and I find Theo Richel’s comment puzzling as the MA does discuss the Sahel.

I downloaded the Drylands chapter from Conditions and Trends and searched for Sahel - and found the MA states that there was little degredation in the Sahel despite statements in other assessments:

“Recognizing the lack of adequate data on land degradation, the MA commissioned a desk study (Lepers 2003; Lepers et al. 2005) that compiled more-detailed (and sometimes overlapping) regional data sets derived from literature review, erosion models, field assessments, and remote sensing. This study found less alarming levels of land degradation (soil plus vegetation) in the drylands (including hyper-arid regions). Achieving only partial coverage, and in some areas relying on a single data set, it estimated that only 10% of global drylands were degraded. This includes 17% of drylands in Asia degraded, but in the Sahel region in Africa—an area reported as highly degraded by the Global Assessment (Oldeman et al. 1991) and by Dregne and Chou (1992)—few localities with degradation were found. The global number of people who live on lands determined by Lepers (2003) as degraded is about 20 million, much lower than the 117.5 million people living on lands defined as degraded by GLASOD.”- (page 637, C&T)

]]> By: Theo Richel http://rs.resalliance.org/2006/02/03/perspective-on-the-millennium-ecosystem-assessment/#comment-165 Theo Richel Wed, 01 Mar 2006 23:14:07 +0000 http://blog.resalliance.org/?p=126#comment-165 As a journalist from the Netherlands I was reading the special issue 'The greening of the Sahel'( J. Arid Environments nov 2005) to which you also refer elsewhere on this blog. Here it is shown that the Sahel area has been greening in the past decennia and this is ascribed for a substantial part to increased rainfall. But then I read here about the Millennium Assessment which is supposed to be 'the most thorough survey of global ecosystems ever undertaken'. Well I havent read the MA, but I checked the part of it that deals with desertification and especially the Sahel. What a contrast: 'Model results suggest that land degradation leads to a substantial reduction in water recycling and may have contributed to the observed trend in rainfall reduction in the region over the last 30 years.' Delving deeper in the MA I see the confirmation why I refused to read the report in an earlier stage: this is a multi-organisation report not so much intended to critically assess the state of the planet, but more as a modern version of the French Marseillaise: Allons enfants de la Patrie! Its a public relations-effort and those only succeed if you obscure the different opinions that one (luckily) encounters in the scientific world. That is why the good news about the Sahel is hidden in the MA (not present actually). Good news would suggest the troops that the battle is won already and that is not the message our pr-officers want to convey. So while I cannot deny that there may be useful information in the MA, I will not read it any further because it is so biased. And yes one example is enough for that. I didnt know about the Zayed price though. Interesting As a journalist from the Netherlands I was reading the special issue ‘The greening of the Sahel’( J. Arid Environments nov 2005) to which you also refer elsewhere on this blog. Here it is shown that the Sahel area has been greening in the past decennia and this is ascribed for a substantial part to increased rainfall.
But then I read here about the Millennium Assessment which is supposed to be ‘the most thorough survey of global ecosystems ever undertaken’. Well I havent read the MA, but I checked the part of it that deals with desertification and especially the Sahel. What a contrast: ‘Model results suggest that land degradation leads to a substantial reduction in water recycling and may have contributed to the observed trend in rainfall reduction in the region over the last 30 years.’

Delving deeper in the MA I see the confirmation why I refused to read the report in an earlier stage: this is a multi-organisation report not so much intended to critically assess the state of the planet, but more as a modern version of the French Marseillaise: Allons enfants de la Patrie! Its a public relations-effort and those only succeed if you obscure the different opinions that one (luckily) encounters in the scientific world. That is why the good news about the Sahel is hidden in the MA (not present actually). Good news would suggest the troops that the battle is won already and that is not the message our pr-officers want to convey. So while I cannot deny that there may be useful information in the MA, I will not read it any further because it is so biased. And yes one example is enough for that.
I didnt know about the Zayed price though. Interesting

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