In this millennium, global drylands face a myriad of problems that present tough research, management, and policy challenges. Recent advances in dryland development, however, together with the integrative approaches of global change and sustainability science, suggest that concerns about land degradation, poverty, safeguarding biodiversity, and protecting the culture of 2.5 billion people can be confronted with renewed optimism. We review recent lessons about the functioning of dryland ecosystems and the livelihood systems of their human residents and introduce a new synthetic framework, the Drylands Development Paradigm (DDP). The DDP, supported by a growing and well-documented set of tools for policy and management action, helps navigate the inherent complexity of desertification and dryland development, identifying and synthesizing those factors important to research, management, and policy communities.

There is a scientific consensus regarding the reality of anthropogenic climate change. This has led to substantial efforts to reduce atmospheric greenhouse gas emissions and thereby mitigate the impacts of climate change on a global scale. Despite these efforts, we are committed to substantial further changes over at least the next few decades. Societies will therefore have to adapt to changes in climate. Both adaptation and mitigation require action on scales ranging from local to global, but adaptation could directly benefit from climate predictions on regional scales while mitigation could be driven solely by awareness of the global problem; regional projections being principally of motivational value. We discuss how recent developments of large ensembles of climate model simulations can be interpreted to provide information on these scales and to inform societal decisions. Adaptation is most relevant as an influence on decisions which exist irrespective of climate change, but which have consequences on decadal time-scales. Even in such situations, climate change is often only a minor influence; perhaps helping to restrict the choice of 'no regrets' strategies. Nevertheless, if climate models are to provide inputs to societal decisions, it is important to interpret them appropriately. We take climate ensembles exploring model uncertainty as potentially providing a lower bound on the maximum range of uncertainty and thus a non-discountable climate change envelope. An analysis pathway is presented, describing how this information may provide an input to decisions, sometimes via a number of other analysis procedures and thus a cascade of uncertainty. An initial screening is seen as a valuable component of this process, potentially avoiding unnecessary effort while guiding decision makers through issues of confidence and robustness in climate modelling information. Our focus is the usage of decadal to centennial time-scale climate change simulations as inputs to decision

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Spectral analysis of the sub-tropical percentage data (Fig. 4) indicates coherence with the 23±19-kyr oscillations (precession) just below the 80% con®dence interval. The effects of the seasonality and precipitation produced by the increased amplitude of the seasonal cycle of solar radiation appear to have had a signi®cant in¯uence on the distribution and composition of the sub-tropical vegetation in the Hungarian late Pliocene.The pollen spectrum of both taxonomic groups (that is, boreal and sub-tropical) is, however, dominated by a strong low-frequency component of ,124 kyr. Even though there are only at most three cycles to be resolved in this data set, such variance is clearly visible in the record (Fig. 3). This is of particular signi®cance, as the 124-kyr peak is non-existent in the calculated insolation forcing (Fig. 4) 15 .There is some evidence from oceanic records of signi®cant environmental change at the 95±124-kyr interval. Dust data in deep sea cores exhibit a strong response at this period in the time interval considered here 20 . Changes in atmospheric dust content are thought to re¯ect directly changes in continental aridity and terrestrial vegetation cover 21 , but until now there has been little direct pollen evidence to support this suggestion. The 124-kyr variance observed in our pollen record strongly supports the link between the dust content observed in marine cores and terrestrial vegetation change.The results from Pula thus indicate that in addition to forcing at the orbital frequencies of precession and obliquity, internally driven nonlinear responses of the climate system at a period of ,124 kyr were as important (if not more important) in driving terrestrial vegetation dynamics and were presumably associated with this broad-scale environmental change. This terrestrial sequence provides the basis for beginning to understand the physical relationships between vegetation, ice volume and insolation forcing during a critical period in the Earth's climate system. M

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Seasonal climate outlooks provide one tool to help decision-makers allocate resources in anticipation of poor, fair or good seasons. The aim of the 'Climate Outlooks and Agent-Based Simulation of Adaptation in South Africa' project has been to investigate whether individuals, who adapt gradually to annual climate variability, are better equipped to respond to longer-term climate variability and change in a sustainable manner. Seasonal climate outlooks provide information on expected annual rainfall and thus can be used to adjust seasonal agricultural strategies to respond to expected climate conditions. A case study of smallholder farmers in a village in Vhembe district, Limpopo Province, South Africa has been used to examine how such climate outlooks might influence agricultural strategies and how this climate information can be improved to be more useful to farmers. Empirical field data has been collected using surveys, participatory approaches and computer-based knowledge elicitation tools to investigate the drivers of decision-making with a focus on the role of climate, market and livelihood needs. This data is used in an agent-based social simulation which incorporates household agents with varying adaptation options which result in differing impacts on crop yields and thus food security, as a result of using or ignoring the seasonal outlook. Key variables are the skill of the forecast, the social communication of the forecast and the range of available household and community-based risk coping strategies. This research provides a novel approach for exploring adaptation within the context of climate change.

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