Climate change and desertification: Where do we stand, where should we go?

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Article

Reference

Climate change and desertification: Where do we stand, where should we go?

VERSTRAETE, Michel M., et al.

Abstract

The 2007 edition of the Global Change Research Workshops brought over 50 researchers from all over the world toWengen, Switzerland to review the state of the art with respect to desertification, particularly in the light of climate change. They set out to identify critical knowledge gaps and make recommendations for further research from a wide range of perspectives in both the natural and social sciences. Recent achievements both within discipline and new inter-disciplinary areas were highlighted. Effective communication between the researchers and high-level users of synthetic environmental information, such as international agencies, development programmes and concerned organizations operating in the field was emphasised. This introductory paper provides background to the workshop and highlights the key findings and outcomes of the conference. The findings that emerged from those discussions are summarized, and some further thoughts about recommended next steps are provided

VERSTRAETE, Michel M., et al . Climate change and desertification: Where do we stand, where should we go? Global and Planetary Change , 2008, vol. 64, no. 3-4, p. 105-110

DOI : 10.1016/j.gloplacha.2008.09.003

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Editorial

Climate change and deserti ﬁ cation: Where do we stand, where should we go?

Michel M. Verstraete

^a,

⁎ , Andreas B. Brink

^a

, Robert J. Scholes

^b

, Martin Beniston

^c

, Mark Stafford Smith

^d

aInstitute for Environment and Sustainability (IES), DG-Joint Research Centre (JRC), European Commission, I-21020 Ispra (VA), Italy

bNatural Resources and the Environment (NRE), Council for Scientiﬁc. and Industrial Research (CSIR), Pretoria 0001, South Africa

cEnvironmental Sciences, University of Geneva, CH-1227 Carouge (GE), Switzerland

dCSIRO Sustainable Ecosystems & Desert Knowledge CRC, P. O. Box 286, Canberra, ACT 2602, Australia

a b s t r a c t a r t i c l e i n f o

Article history:

Received 11 August 2008 Accepted 18 September 2008 Available online 19 October 2008 Keywords:

Climate change Desertiﬁcation

The 2007 edition of the Global Change Research Workshops brought over 50 researchers from all over the world to Wengen, Switzerland to review the state of the art with respect to desertification, particularly in the light of climate change. They set out to identify critical knowledge gaps and make recommendations for further research from a wide range of perspectives in both the natural and social sciences. Recent achievements both within discipline and new inter-disciplinary areas were highlighted. Effective communication between the researchers and high-level users of synthetic environmental information, such as international agencies, development programmes and concerned organizations operating in thefield was emphasised. This introductory paper provides background to the workshop and highlights the keyfindings and outcomes of the conference. Thefindings that emerged from those discussions are summarized, and some further thoughts about recommended next steps are provided.

1. Introduction

The Wengen Workshops on Global Change Research, currently overseen by the University of Geneva, Switzerland, were initiated in 1995 to address complex issues related to climate and environmental change from an international, cross-disciplinary point of view. These events bring together world-recognized experts from different back- grounds to present leading-edge research results, to discuss issues and solutions, and to pave the way for future research directions. These yearly Wengen Workshops have traditionally been held in the Swiss Alpine resort of the same name, in the early autumn.

Since 1995, meetings have broadly focused on global change, including climate change and other processes with global consequences, and especially in their implications for a range of environmental, social, economic and political issues (e.g., forest management and biomass burning; hydrology and water management; health;

population migrations; the economic, social and cultural impacts of glacier melt; etc.). In addition, some targeted technical workshops have focused on topics such as carbon sinks as a means of addressing the commitments of governments to the Kyoto Protocol, or linking satellite data and climate models, and have helped to further our understanding of the intricacies of climate and its major components.

Further information on these events can be found on the following web site: http://www.unige.ch/climate/Workshops/wengen.html.

These meetings typically result in a peer-reviewed publication of the

key papers presented at the meeting, which aims to convey the main conference ﬁndings to the scientiﬁc and policy communities, as appropriate.

The 13th Wengen Workshop focused on the issue of 'Climate Change and Desertification' and took place from 10 to 13 September 2007. It assembled some 50 scientists and experts in variousfields, from climate to policy making and from remote sensing to livestock management. The goals of the workshop were to step back and review (1) where we are and what we have learned about desertification processes over the last three decades, (2) the current state of the art in this and relatedfields (monitoring, modelling, integration of natural and social sciences, historical background, etc), and (3) where we are heading, given the high likelihood of significant climate changes in the coming decades, with a view to recommend priorities for further research and monitoring activities in this broad interdisciplinaryfield.

The participants also discussed the best ways to convey the main scientificfindings to policy makers and actors on the ground, and, more generally, to promote a renewed and revived dialogue between the scientific community, UN organizations, governmental and non- governmental organizations with an interest in desertification.

This Wengen workshop coincided with the 30th anniversary of the holding of the UN Conference on Desertification in Nairobi (UNCOD, September 1977) and took place just over 10 years after the entry into force of the UN Convention to Combat Desertification (UNCCD, December 1996). Desertification had also been investigated in depth during the Millennium Assessment (2001–2005), and the UN General Assembly declared 2006 to be the International Year of Deserts and Desertification (IYDD,Stringer, 2008). These events attest that the issue has remained a nagging problem for decades, despite considerable Global and Planetary Change 64 (2008) 105–110

⁎ Corresponding author. Tel.: +39 03 32 78 55 07; fax: +39 03 32 78 90 73.

E-mail address:Michel.Verstraete@jrc.it(M.M. Verstraete).

doi:10.1016/j.gloplacha.2008.09.003

Contents lists available atScienceDirect

Global and Planetary Change

j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / g l o p l a c h a

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efforts and investments in projects to address the problem; and climate change is likely to exacerbate the implications of desertiﬁcation (MEA 2005).

The workshop was structured around six sessions addressing both scientiﬁc and policy issues, from the points of view of monitoring and modelling, long term past and recent developments, degradation processes as well as research approaches and policy implications. The conference programme, the titles of the 15 posters exhibited during the meeting, a list of participants and theﬁnal report of the workshop are available from the meeting web site at http://www.unige.ch/

climate/Workshops/wengen07.html.

2. Key themes and mainﬁndings

This collection of papers assembles a variety of written contributions from participants at the workshop. This prefatory paper places those contributions in the broader context.

The workshop accepted the UN Convention on Combating Desertification definition of desertification as ‘land degradation in drylands’(where drylands are defined as regions where the mean annual precipitation is less than 2/3 of the potential evaporative demand). It further accepted theMillennium Ecosystem Assessment (2005) elaboration of the meaning of ‘degradation’ as being a persistent loss of the sum of services delivered by the ecosystem.

The workshop participants endorsed the overall conceptual framework for the analysis of desertification, recently proposed by Reynolds et al. (2007). This new approach, the Dryland Development Paradigm (DDP), offers a comprehensive, formal framework to investigate environmental and socio-economic problems in drylands in an interdisciplinary way. The DDP emphasises (i) the links between the human and environmental components of dryland issues; (ii) the identification of key slow variables that control these linked human- environment systems; (iii) the importance of managing the thresholds in these slow variables; (iv) the heterarchically nested structure of these systems, and (v) the critical importance of local environmental knowledge to keep human management decisions in tune with the functioning of the system. It remains to be exhaustively tested in practical situations but already provides a more structured context to cast issues and to evaluate possible solutions than the hodgepodge of largely disciplinary (if not sectarian) ideas and somewhat artificial or conflictual positions prevailing until then.

Aridity and the associated vagaries of climate variability have often been constraints on the development of human societies; they may even have fostered major technological advances such as agriculture, the invention of irrigation systems, or settlements. Entire civilizations have disappeared in the past for not being able to cope with externally driven climate changes, or because the land management which they practiced was unsustainable in the environments in which they occurred. Humanity may now be facing just such a challenge, but on a scale that has not been witnessed in historical times (Hughes and Diaz, 2008-this issue).

Recent research into the net effect of sea surface temperature changes on atmospheric circulation patterns, exemplified by the El Niño and other oscillations, has shown that the bulk of the variability in precipitation levels in the Sudano-Sahelian region may be directly related to observed changes in water temperature in the Gulf of Guinea (Giannini et al., 2008-this issue). This importantfinding forces a re-assessment of the ultimate causes of desertification. Formerly it was believed that desertification was largely a local (or at most, regional) phenomenon caused by locally inappropriate land management. Thefinding that, in this iconic case, a globally-driven process was more likely to be the key factor should stimulate the necessary debate on how, where and when to address desertification symptoms.

The validity of the conclusions drawn from climate model simulations has long been a focus of great interest, both in the scientiﬁc community and amongst users (or sceptics) of these results.

These models, though very detailed and nowadays much more complex than even a few years ago, still struggle to represent a number of important physical processes occurring at scales much finer than the intrinsic resolution of the models. They attempt to achieve this through parameterizations and simplifications, because of the practical and numerical difficulties of incorporating more processes and details (IPCC, 2007; Doherty et al., in press). A comparison of the land surface parameterization schemes in a subset of such models uncovered a number of open issues that need to be addressed (Henderson-Sellers et al., 2008-this issue) if these models are to generate information that can be relied upon for policy making.

Our understanding of the processes that control climate and environmental systems results from the confrontation between explicit, formal representations of current knowledge and empirical evidence such as provided by observations and experiments.

Measurements of the state of these systems serve to both investigate past evolutions and to set the stage for predictions (forecasts as well as educated scenarios). Signiﬁcant progress has been accomplished in the last few years on the retrieval of essential climate variables (GCOS, 2004) from space-borne Earth Observation platforms.Govaerts and Lattanzio (2008-this issue)discuss speciﬁcally how remote sensing observations from the Meteosat family of geostationary satellites are being exploited to retrieve reliable estimates of land surface albedo over Africa, for an extended period of time. This geophysical variable is both an indicator of land degradation and a key factor controlling the energy balance of the climate system over continental areas.

Remote sensing products have long been used to characterize the degradation of land surfaces.Hill et al. (2008-this issue)discuss the use of traditional techniques to monitor desertiﬁcation and land degradation in the Mediterranean region, taking a syndrome based approach to understanding the trajectories of different regions.

Meanwhile Helldén and Töttrup (2008-this issue) apply such techniques in broad areas subject to desertiﬁcation, from Senegal to Mongolia, building on the experience gained from a number of earlier projects that focused on this issue. One of the central issues debated on this occasion was the reality and probable persistence of a postulated‘greening-up’of the Sahelian region in recent years.

During the workshop,Gobron et al. (2005, 2007)had explained how innovative remote sensing products, such as the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), are currently derived from reﬂectance measurements in the solar spectral domain, and showed how deviations of this product from suitably deﬁned spatial and temporal averages can be used to characterize the impact of drought events on the vegetation cover.

Many of the discussions that took place during the workshop revolved around the tools and techniques that could or should be deployed to document and better understand environmental degradation processes, and especially to better integrate the human aspects of desertiﬁcation in a comprehensive, interdisciplinary framework.

Helldén (2008-this issue), for instance, described the design and exploitation of a conceptual model taking advantage of systems engineering methods (speciﬁcally using the STELLA modelling environment), to incorporate both the availability of natural resources and the impact of demographic pressure into a diagnostic as well as prognostic tool. These efforts may seem very crude in comparison with the extraordinary socio-economic, political or demographic complexity of modern societies, but they do constitute excitingﬁrst steps to explore new ways to interface natural and social sciences.

Koch et al. (2008-this issue) used a rather different modelling approach but similarly addressed the issue of simulating the interaction between socio-economic forces and natural resources, this time in a grazing community in Jordan. One of the advantages of such models is that, to the extent they include correct representations of the key interactions, they allow investigations of multiple speciﬁc scenarios of population growth, climate changes and other constraints (such as availability of fodder, land use changes or the impact of

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taxation) as well as an estimation of the future evolution of the entire system over periods of multiple years or decades.

Islands are interesting environments to study, because their natural isolation and (often) restricted size limit the number of processes that may be required to explain an observed evolution.

Olehowski et al. (2008-this issue) investigated the vulnerability of Fogo Island (Cape Verde) to stresses such as highly variable precipitation, population increase, agricultural expansion and tour- ism. Remote sensing, geographical information systems and geosta- tistical methods are combined to analyse the available data and generate a web of information layers on which to base further studies as well as development decisions.

The integration of the biophysical and socio-economic dimensions of land degradation is taken a step further byLorent et al. (2008-this issue)who evaluated, through surveys of the concerned population, the effect of subsidies on the proﬁtability of traditional agricultural activities in Greece, and combined these ﬁndings with spatially- explicit biophysical information derived from remote sensing. Much remains to be done to develop methodological tools and procedures to usefully integrate data that may be qualitative in nature or not explicitly geo-referenced into a common framework that can also accommodate environmental descriptors, but this project hints at the potential to develop local typologies of social responses.

A further example of integrating the biophysical and socio- economic domains is provided by the study ofMbow et al. (2008- this issue), who analyse historical environmental changes in eastern Saloum-Senegal, the drivers and local perceptions of these changes and the adaptation pathways of the affected population. Several information layers ranging from archival data, remote sensing-based land cover change data and household interviews allowed them to monitor the co-evolution of environmental conditions as well as human and societal management mechanisms in Senegal since the 1950s. The study shows that while climate variability has influenced environmental change in the area, various types of State interventions in agriculture and global marketfluctuations appear to have been the main underlying causes of environmental degradation. The complexity of the rural‘system’makes it difficult to discriminate adaptation strategies related to one of these specific stresses, therefore a given adaptation action is likely to be an adjustment to several factors.

Climate change and desertiﬁcation will have a major impact on the poorest and therefore most vulnerable part of the global population.

Predicting future hotspots of hunger in the context of the anticipated climate, social, economic, and bio-physical changes can serve to better plan adaptive measures to combat poverty and food insecurity. A spatially explicit model of current and future hotspots of food insecurity in sub-Saharan Africa is presented byLiu et al. (2008-this issue). Their approach, valid at a sub-national level, focuses on the assessment of the number of undernourished people and the impact of climate change on crop production for six major crops in sub- Saharan Africa. The hotspots of future food insecurity are identiﬁed in the context of future global changes in population, GDP, and crop production.

Research efforts on climate change and desertification aim to contribute to sustainable living in arid lands and to significantly enhance livelihoods of the local population. A key question in this context is the accessibility of scientific information to the users and decision makers.Seely et al. (2008-this issue)explain the concept of so called ‘boundary organizations’, which serve as multi-directional communication platforms and facilitators between those who generate the research to those who apply the results, hence ensuring an information loop and feed-back mechanism between these two entities.

According to the Intergovernmental Panel on Climate Change (IPCC), the way land degradation issues are managed and sustainable development pathways are defined is governed by the institutional context in which certain policies are made and implemented. In this context,Spiess (2008-this issue)presents an interesting case study on the Gulf Cooperation Council where she highlights some of the major political and institutional constrains with respect to the definition of these pathways and the handling of climate change and desertification issues.

3. Challenges and opportunities

Unravelling the tangled syndrome of environmental, human and development issues known as ‘desertiﬁcation’ has remained an elusive goal, even though hundreds of publications are being issued on the subject each year (Fig. 1).

Fig. 1.Number of publications published per year on 'desertiﬁcation' (dashed line) and 'climate and desertiﬁcation' (continuous line), as reported by SCOPUS, from 1960 to 2007.

Additional labels indicate the occurrence of major international conferences or events.

107 M.M. Verstraete et al. /Global and Planetary Change 64 (2008) 105–110

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Four world-renowned researchers were invited to contribute major presentations at the United Nations Conference on Desertiﬁca- tion in 1977. These syntheses were published in book form (UNCOD, 1977) and long remained the scientiﬁc basis for research and action.

However, the scientific and policy making communities seem to have rapidly diverged after that conference. By the time the United Nations Convention on Desertification (UNCCD) was signed, a Committee on Science and Technology (CST) was established, but that structure never seemed to have the scientific aura or the effectiveness of the Intergovernmental Panel on Climate Change (IPCC), established in 1988 to support the UN Framework Convention on Climate Change.

The continuing estrangement of the science and policy in theﬁeld of desertiﬁcation is detrimental to the successful cure of this serious problem.

Major advances in science and technology had taken place over the last few decades, and it will be both appropriate and timely to bring these new capabilities to bear on the development of drylands, in a manner that is both effective for the populations concerned and respectful of the constraints imposed by climate and ecological processes.

One of the key challenges, as far as the scientific community is concerned, remains the difficulty in bridging the gap between natural and social sciences. Few research teams have addressed this issue, though some notable progress has been made. From a conceptual point of view, the recently proposed Drylands Development Paradigm (DDP) (Reynolds et al., 2007) constitutes a useful step towards building an overarching intellectual framework that can integrate contributions from differentfields of research. This needs to be both expanded and evaluated to ensure its value and wide applicability. The papers included in this collation will hopefully contribute further to this goal.

New tools, approaches, methodologies, and measurement protocols will be required to support genuine interdisciplinary research. For instance, as pointed out by Lorent et al. (2008-this issue), social science data may not be geo-located and thus difficult to combine with more traditional geophysical data. The issues of scale also remain problematic, with field measurements and surveys on the ground operating at much finer resolutions than those typical of remote sensing techniques, for example. Well structured, nested typologies may be needed to link results at these different scales.

Computational power and communication technologies have continued to grow at an unabated rate. While these tools have greatly helped the scientiﬁc community in its daily activities, little appears to have been done to leverage these advances in terms of local development opportunities, or even to enhance research capacity in emerging countries, or to facilitate a better integration of scientists and organizations in those countries with the most advanced components of the research establishment worldwide. Many participants in the Wengen workshop expressed a strong desire and willingness to have access to better tools, especially if these could be used locally or regionally to address practical problems. Addressing these issues effectively will require much more than just transferring software codes: steps should be taken to strengthen the entire scientiﬁc infrastructure, build-up communication networks, transfer knowledge through intensive training programmes, facilitate access to equipment and instruments, etc.

One area of potentially great importance in this respect is the entireﬁeld of space applications. Three categories of applications have leveraged systematic access to space platforms: telecommunications, navigation and Earth Observation. In this latter case, the availability of long time series of optical, thermal and microwave observations, globally and at increasinglyﬁner spatial resolutions is most appropriate to conduct research on the past evolution of the environment and societies, and to support current and planned development projects. The effective use of these technologies hinges, however, on the access and mastery of the knowledge, expertise and know-how

required to transform raw data into useful information. Remote sensing approaches which may have been appropriate 20 years ago are nowadays wholly inadequate to take advantage of the advanced features and speciﬁcations of current or future sensors. The forth- coming GMES-Africa programme, a component of the Joint EU-Africa Strategy¹, provides a natural framework for further activities in this regard, at least as far as scientists, organizations and nations of that continent are concerned.

Monitoring the state and evolution of the environment in drylands will continue to be a high priority, both to support development programmes and policy planning, as well as to provide the data required to conduct research on the causes and consequences of recent changes, or to estimate likely future changes. This will require substantial new R&D efforts, both to identify more relevant environmental and human variables to measure, and to ensure a more systematic, integrated approach to combine information gathered at different scales and resolutions, eventually with other data that may not even be geo-located (e.g.,Verstraete et al., in press).

4. Next steps

Significant further events and developments will take place in the coming years, and should serve to prompt all partners in this venture to get their act together. The African Union has been developing a long-term strategy of collaboration and co-development with the European Union, in a wide range of sectors including environment and space matters. Specifically, a Global Monitoring for Environment and Security (GMES) programme designed to address African issues has been approved at an AU-EU joint conference in Portugal in 2007. A specific Action Plan should become available by the time of the next summit, expected to take place in late 2009 or early 2010.

The participants in the Wengen Workshop discussed the need to better coordinate the remote andﬁeld observations and measurements made of drylands, both for biogeophysical and for social sciences, and suggested the creation of a Global Drylands Observing System (GDOS) to complement the existing Global Climate Observing System (GCOS) and the Global Terrestrial Observing System (GTOS).

Such a structure would not duplicate existing systems but ensure a better focus on drylands and in particular address the interdisciplinary issues that have been identiﬁed earlier. Such an effort would support the further development of knowledge and expertise on drylands, the understanding of the processes at work, and the practical actions in theﬁeld by making available reliable, accurate information. It would also contribute to the practical integration of natural and social sciences, paying much attention to the issue of delivering useful information to all concerned stakeholders.

Decisive efforts need to be undertaken to increase the relevance of scientiﬁc research for policy making and in support of development in general. New mechanisms and institutions will be needed to facilitate the communication between these communities, in particular to overcome the difﬁculties associated with technical jargon and differences in methods. Nevertheless, no substantial progress can be expected in improving the situation of drylands without a more adequate exchange of knowledge and expertise, especially to take advantage of the local knowledge available within the traditions and societies that currently live in drylands.

The scientiﬁc community of emerging countries urgently needs to be reinforced and better integrated within the local policy and development processes, as well as with the global research community. This will imply major investments in capacity building and training, but also investments in equipments and infrastructure.

A closer integration of the scientiﬁc efforts that are supposed to guide UNCCD with those that support UNFCCC is highly desirable.

1 The full text of this strategy is available fromhttp://www.grices.mctes.pt/gpe/

images/stories/File/PT_Presid_GMES_Africa_Lisbon_Declaration.pdf.

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While the CST may not need to be structured like the IPCC, its scientiﬁc standing and practical relevance should increase signiﬁcantly.

At the conclusion of the Wengen workshop, the participants adopted a set of recommendations, which are summarized as follows (the original list is available from the workshop report mentioned earlier):

1. The nature and predictability of teleconnections (observed correla- tions between large scale geophysical processes, for instance between precipitation in the Sahel and sea surface temperature) should be investigated further, with a view to adapting development strategies to use them or taking advantage of them for recovery actions.

2. The data collection, archiving, and distribution infrastructure in countries subject to desertiﬁcation should be signiﬁcantly improved. This will require solving both technical (infrastructure, equipment, communications) and institutional problems (loss of data through disasters and war, data access rights), but these steps are essential to support meaningful development policies.

3. While further progress is required in individual disciplines, the greatest advances in understanding and in generating directly exploitable knowledge are expected to result from integrated, interdisciplinary research, particularly when dedicated efforts are made to enhance communications and collaborations between the natural and human sciences. The Dryland Development Paradigm (DDP) constitutes an initial step in this direction.

4. Conceptual and mechanistic integrated models of the climate, environment and human aspects of dryland development, operating over a range of spatial and temporal scales, are important tools to formalize our understanding of the processes involved and to generate future scenarios and projections. These models should be further refined, evaluated, integrated and nested, and special efforts are needed to render some of these tools available and usable by extension officers in thefield or by scientists involved with local communities.

5. The speciﬁcity and complexity of the issues at hand, and the current severe limitations of data gathering activities, may justify the creation of a Global Drylands Observing System (GDOS) to organize and harmonize data acquisition and analysis in these regions. Such a system would complement existing efforts in the climate area (e.g., the Global Climate Observing System) and coordinate with the Committee on Earth Observation Satellites (CEOS), and should address the following issues, amongst others:

a. the identiﬁcation of a small number of essential variables, describing relevant aspects of the climate, environment and human issues, and most relevant to understand the processes at work,

b. the development, validation and deployment of standardized tools and algorithms to generate coherent, homogeneous, global, long- term characterization of the state and evolution of the environment on the basis of remote sensing data in a way suitable for ingestion into models or use in practical applications, and the subsequent reprocessing of entire satellite data archives,

c. the standardization of measurement as well as the data exchange protocols, so as to make these observations compatible and comparable,

d. the calibration of the sensors and validation of the products through benchmarking, to ensure their reliability and document their accuracy,

e. the clariﬁcation of data ownership issues, and the promotion of more open access policies for scientiﬁc purposes, and

f. the improvement of the spatial coverage and temporal continuity of data collection activities, not only in the natural but also in the human sciences.

6. Strenuous additional efforts are needed to promote better two-way communications between the major stakeholders, in particular the

scientific, policy making and development communities. This may require establishing ‘boundary organizations’ to facilitate the interaction and translate jargon and meaning between all concerned stakeholders. These efforts should aim at improving, in particular, the support of the scientific community to the Conference of the Parties (COP) to the UN Convention to Combat Desertification (UNCCD), which should avail itself of a strong advisory body of independent scientists capable of providing the understanding necessary to meaningfully address these issues, as is the case for the UN Framework Convention on Climate Change.

The future of a billion people in drylands whose livelihoods (and often lives) depend on natural resources is at risk from desertiﬁcation exacerbated by climate change. An integrated approach to the problem which combines social and biophysical viewpoints, and links local knowledge with the scientiﬁc endeavour is vital if the world is not to fail these people.

Acknowledgments

The Wengen Workshop organizers beneﬁted from the advice and support of the meeting's Scientiﬁc Steering Committee members [Mohamed Badraoui, HCEFLD, Rabat, Morocco; Martin Beniston, University of Geneva, Switzerland; Andreas Brink, EC Joint Research Centre, Ispra, Italy; Filippo Giorgi, ICTP, Trieste, Italy; Joachim Hill, University of Trier, Germany; Malcolm Hughes, University of Arizona, Tucson (AZ), USA; Luca Montanarella, EC Joint Research Centre, Ispra, Italy; Osvaldo Sala, Brown University, Providence (RI), USA; Bob Scholes, CSIR, Pretoria, South Africa; Mary Seely, DRFN, Windhoek, Namibia; David Thomas, Oxford University, UK; and Michel Ver- straete, EC Joint Research Centre, Ispra, Italy]. Their help is gratefully acknowledged.

Organizing and running this workshop would not have been possible without the substantialﬁnancial support of our sponsors.

First of all, the Joint Research Centre of the European Commission [in particular Guido Schmuck, Director (ff) at the time] provided the bulk of the support through direct contributions of four different Actions (SOLO [Mark Dowell], MONDE [Philippe Mayaux], SOILS [Luca Montanarella] and MARS [Olivier Léo]). Two JRC Institutes, IES and IPSC, supported their employees while working on this project. The World Climate Research Programme (WCRP) was instrumental and particularly effective, thanks to an early and quick decision by Prof.

Ann Henderson–Sellers to co-sponsor this event. The GEO Secretariat joined this chorus with a major grant which helped us invite a number of distinguished participants from emerging countries. José Achache, Alexia Massacand and Natasha Brutsch-Dastur played key roles in authorizing and arranging for this support. For many participants from emerging countries, attendance would not have been possible without the very generous support of these institutions. Last but not least, we were able to rely on the University of Geneva for a number of organizational and administrative tasks. This type of support is essential to organize a meeting in a remote place, and the effective, efﬁcient and discreet support of Douglas Cripe and Anthony Lehman was particularly appreciated. The quality of the meeting discussions and the content of these proceedings attest of the vision and level of support we got from our sponsors as well as the expertise and dedication of the participants.

References

Doherty, S.J., Bojinski, S., Henderson-Sellers, A., Noone, K., Goodrich, D., Bindoff, N.L., Church, J.A., Hibbard, K.A., Karl, T.R., Kajfez-Bogataj, L., Lynch, A.H., Parker, D.E., Prentice, I.C., Ramaswamy, V., Saunders, R.W., Stafford Smith, M., Steffen, K., Stocker, T.F., Thorne, P.W., Trenberth, K.E., Verstraete, M.M., Zwiers, F.W., in press. Lessons learned from IPCC AR4: select scientiﬁc developments needed to understand, predict and respond to climate change. Bulletin of the American Meteorological Society.

109 M.M. Verstraete et al. /Global and Planetary Change 64 (2008) 105–110

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Giannini, A., Biasutti, M., Verstraete, M.M., 2008. A climate model-based review of drought in the Sahel: desertiﬁcation, the re-greening and climate change. Glob.

Planet. Change. 64, 119–128 (this issue).doi:10.1016/j.gloplacha.2008.05.004.

Global Climate Observing System (GCOS), 2004. Implementation Plan for the Global Observing System for Climate in support of the UNFCCC, GCOS-92, WMO/TD No.

1219. World Meteorological Organization.http://www.wmo.ch/pages/prog/gcos/

Publications/gcos-92_GIP.pdf.

Gobron, N., Pinty, B., Mélin, F., Taberner, M., Verstraete, M.M., Belward, A., Lavergne, T., Widlowski, J.-L., 2005. The state of vegetation in Europe following the 2003 drought. International Journal of Remote Sensing Letters 26 (No. 9), 2013–2020.

Gobron, N., Pinty, B., Mélin, F., Taberner, M., Verstraete, M.M., Robustelli, M., Widlowski, J.L., 2007. Evaluation of the MERIS/ENVISAT FAPAR product. Advances in Space Research 39, 105–115.doi:10.1016/j.asr.2006.02.048.

Govaerts, Y., Lattanzio, A., 2008. Estimation of surface albedo increase during the eighties Sahel drought from Meteosat observations. Glob. Planet. Change. 64, 139–145 (this issue).doi:10.1016/j.gloplacha.2008.04.004.

Helldén, U., 2008. A coupled human-environment model for desertiﬁcation simulation and impact studies. Glob. Planet. Change. 64, 158–168 (this issue).doi:10.1016/j.

gloplacha.2008.09.004.

Helldén, U., Töttrup, C., 2008. Regional desertiﬁcation: a global synthesis. Glob. Planet.

Change. 64, 169–176 (this issue).doi:10.1016/j.gloplacha.2008.10.006.

Henderson-Sellers, A., Irannejad, P., McGufﬁe, K., 2008. Future desertiﬁcation and climate change: the need for land-surface system evaluation improvement. Glob.

Hill, J., Stellmes, A., Udelhoven, Th., Röder, A., Sommer, S., 2008. Mediterranean desertiﬁcation and land degradation. Mapping related land use change syndromes based on satellite observations. Glob. Planet. Change. 64, 146–157 (this issue).

doi:10.1016/j.gloplacha.2008.10.005.

Hughes, M.K., Diaz, H.F., 2008. Climate variability and change in the drylands of Western North America. Glob. Planet. Change. 64, 111–118 (this issue). doi:10.1016/j.

Intergovernmental Panel on Climate Change (IPCC), 2007. Fourth Assessment Report.

http://www.ipcc.ch/.

Koch, J., Schaldach, R., Köchy, M., 2008. Modeling the impacts of grazing land management on land-use change for the Jordan River region. Glob. Planet. Change.

64, 177–186 (this issue).doi:10.1016/j.gloplacha.2008.09.005.

Liu, J., Fritz, S., van Wesenbeeck, C.F.A., Fuchs, M., L.You, L., Obersteiner, M., Yang, H., 2008. A spatially explicit assessment of current and future hotspots of hunger in Sub-Saharan Africa in the context of global change. Glob. Planet. Change. 64, 221–234 (this issue).doi:10.1016/j.gloplacha.2008.09.007.

Lorent, H., Evangelou, C., Stellmes, M., Hill, J., Papanastasis, V., Tsiourlis, G., Roeder, A., Lambin, E.F., 2008. Land degradation and economic conditions of agricultural households in a marginal region of northern Greece. Glob. Planet. Change. 64, 197–208 (this issue).doi:10.1016/j.gloplacha.2008.05.005.

Mbow, C., Mertz, O., Diouf, A., K.Rasmussen, K., Reenberg, A., 2008. The history of environmental change and adaptation in eastern Saloum–Senegal—Driving forces and perceptions. Glob. Planet. Change. 64, 209–220 (this issue).doi:10.1016/j.

Millennium Ecosystem Assessment, 2005. Ecosystems and Human Wellbeing:

Desertiﬁcation Synthesis. World Resources Institute, Washington, DC.

Olehowski, C., Naumann, S., Fischer, D., Siegmund, A., 2008. Geo-ecological spatial pattern analysis of the island of Fogo (Cape Verde). Glob. Planet. Change. 64, 187–196 (this issue).doi:10.1016/j.gloplacha.2008.09.006.

Reynolds, J.F., Stafford Smith, D.M., Lambin, E.F., Turner II, B.L., Mortimore, M., Batterbury, S.P.J., Downing, T.E., Dowlatabadi, H., Fernandez, R.J., Herrick, J.E., Huber-Sannwald, E., Jiang, H., Leemans, R., Lynam, T., Maestre, F.T., Ayarza, M., Walker, B., 2007. Global desertiﬁcation: building a science for dryland development.

Science 316 (No. 5826), 847–851.doi:10.1126/science.1131634(11 May 2007).

Seely, M., Dirkx, E., Hager, C., Klintenberg, P., Roberts, C., von Oertzen, D., 2008. Advances in desertiﬁcation and climate change research: Are they accessible for application to enhance adaptive capacity? Glob. Planet. Change. 64, 235–242 (this issue).

doi:10.1016/j.gloplacha.2008.07.006.

Spiess, A., 2008. Developing adaptive capacity for responding to environmental change in the Arab Gulf States: uncertainties to linking ecosystem conservation, sustainable development and society in authoritarian rentier economies. Glob.

Stringer, L.C., 2008. Reviewing the international year of deserts and desertification 2006: what contribution towards combating global desertification and implement- ing the United Nations convention to combat desertification? Journal of Arid Environments, 72, 2065–2074.

United Nations Conference on Desertiﬁcation (UNCOD), 1977. Desertiﬁcation: Its Causes and Consequences. Pergamon Press, 448 pp., ISBN 0 08 022023 1.

Verstraete, M.M., Scholes, R.J., Stafford Smith, M., in press. Climate and desertiﬁcation:

looking at an old problem through new lenses. Frontiers in Ecology and the Environment.