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Effective response by government and individuals to the risk of land degradation requires an understanding of regional climate variations and the impacts of climate and management on condition and productivity of land and vegetation resources. Analysis of past land degradation and climate variability provides some understanding of vulnerability to current and future climate changes and the information needs for more sustainable management. We describe experience in providing climate risk assessment information for managing for the risk of land degradation in north-eastern Australian arid and semi-arid regions used for extensive grazing. However, we note that information based on historical climate variability, which has been relied on in the past, will now also have to factor in the influence of human-induced climate change. Examples illustrate trends in climate for Australia over the past decade and the impacts on indicators of resource condition. The analysis highlights the benefits of insights into past trends and variability in rainfall and other climate variables based on extended historic databases. This understanding in turn supports more reliable regional climate projections and decision support information for governments and land managers to better manage the risk of land degradation now and in the future.

Recent years have witnessed a global increase in more intense, widespread and frequent fires that threaten human security and ecosystems and contribute to green house gas emissions which result in climate change with feed-backs on both fire patterns and land degradation. The interplay between fire weather-risk and land degradation is complex and involves several non linear inter-actions that influence trends in both fire patterns and land degradation processes. Majority of fires are lit by humans but the influence of humans on fire patterns is closely related to fire weather. Weather conditions are the main factors of fire readiness in a given fire prone area. Frequent and more intense fires reduce bio-mass supported in an area, affecting the productive soil layer which leads to soil erosion, change in species composition and a general decline in biodiversity and hence land degradation. In this regard fire is an agent of land degradation which is defined here as a persistent reduction in the capacity of ecosystems to supply services. In arid to semi-arid and dry sub-humid areas, extensive burning may be followed by low rainfall periods thus exposing soil to erosion agents such as heat, and wind and subsequent encroachment of the area by fast growing weeds when normal rainfall return which increases fire risk in that area than before.

Of major concern is how climate change will influence the interaction between fire weather and land degradation. Observations in different regions already link more intense fires witnessed in the past decade to climate change generated hotter and drier summer weather, in addition to fire suppression practices. Prolonged drought under climate change is likely to intensify land degradation due to land use pressure setting conditions for the spread of more fast growing highly flammable weeds during the onset of rainfall. Current evidence suggests that in arid to semi-arid lands, invasive highly flammable herbaceous species associated with degraded lands may out-compete native vegetation during abnormally wet periods under climate change. And with increased fire weather-risk, these areas will undergo increased hot fires facilitated by accumulated dry highly flammable biomass of these invasive species and hence putting the landscape under a perpetual cycle of increased susceptibility to land degradation and fire. Future land degradation studies need to put greater emphasis on the role of fire weather for a better assessment of burning conditions and interaction with land degradation processes.

Drought is a normal feature of climate, but also one of the most common and severe of natural disasters. In most world regions the economic damages caused by droughts are greater than those caused by any other events such as earthquakes and volcanic eruptions. World-wide population growth has intensified the pressure on water resources and increased the vulnerability to drought. Prolonged drought cycles are a major factor in land degradation processes and affect extensive geographical areas. While such a natural hazard may strike any climatic region, its occurrence is more frequent in arid and semiarid regions. According to long term rain measurements, Israel with its Mediterranean climate, has experienced three consecutive dry years for every 50 years period. The recent drought of 1998–2001 in northern Israel was the most extreme during the last 130 years. It affected the water flow of the Jordan River and brought the level of Lake Kinneret to its lowest point in historical periods. Changes in land-use, water pumping and flow diversion, have exacerbated the negative impact of droughts and caused land degradation, such as the drying of wetlands and salinization of freshwater aquifers. The increased use of urban treated waste water for irrigation, with its significantly higher salt content, is another cause of soil degradation, and has a major economic impact on irrigated farming schemes. Wetlands and aquatic environments around Lake Kinneret and other regions of the country, were practically dry for six consecutive years, affecting fish-breeding and endemic aquatic species. Various solutions have been applied: drip irrigation, recycling of wastewater, reduced allocations and increased pricing of water supplies, desalinization plants, etc. However, the failure by successive governments to introduce drought contingency planning and sustainable management of water resources, has already damaged agriculture and nature conservation. The imminent dangers of drought are liable to lead to a major crisis in the country’s water resources and affect all sectors of society.

The relationship between agriculture and environment could be viewed as conflicting (win-lose) or as synergistic (win-win). A win-lose situation is occurring when agricultural activities such as clearing forest for cultivation is leading to environmental degradation or when environmental protection prevents agricultural activity. A synergistic approach, on the other hand, assumes that sustainable environmental management and agricultural production can be achieved simultaneously. One central goal of the Global Environment Facility (GEF) and UNEP is to mainstream sustainable land management into sectors such as agriculture and forestry, thus assuming that win-win situations are possible. The different conceptual frameworks that UNEP has applied and developed in its GEF-funded land degradation projects highlight different aspects of the relationship between agriculture and environment.

The paper draws on 10 years of UNEP/GEF experience in working at the environment-agriculture nexus starting with the People, Land Management and Environmental Change Project (PLEC). PLEC illustrates the potential for synergies between environmental and developmental objectives by developing sustainable and participatory approaches to biodiversity management and conservation based on farmers’ technologies and knowledge within agricultural systems. The Land Use Change, Impacts and Dynamics Project (LUCID) developed a model on how to use land use change analysis in combination with social and economic variables as a tool to assess biodiversity loss and land degradation across landscapes. The Millennium Ecosystem Assessment (MA) assessment framework offers a mechanism for decision-makers to: (1) identify options that can better achieve core human development and sustainability goals; and (2) better understand the trade-offs involved in decisions concerning the environment. The Land Degradation Assessment in Drylands (LADA) uses the (DPSIR) framework in analysing the environment-agriculture nexus in drylands.

This overview shows how the relationship between agriculture and environment can be analysed using different models and approaches depending of scale and level of analysis. The PLEC model is useful at the local level in reconciling environmental and livelihood goals. Land use change analysis is a useful tool at the landscape level in analysing drivers of land degradation and biodiversity loss. The ecosystem services approach by the MA provides a tool for decision-makers at national level to make informed decisions about trade-offs between agriculture/human well-being and the environment. Finally, LADA will use the DPSIR framework for integration of information collected at different scales, from the local to the global.

Landslides are significant natural hazards that degrade the productivity of soils, harm humans, and damage property. Extended and intense rainfall is the most common triggering mechanism of landslides worldwide. Sites are most susceptible to landsliding during wet antecedent conditions. Typically deep-seated, slow moving landslides (e.g., earthflows, slumps) are triggered or reactivated by an accumulation of precipitation over several days or weeks. In contrast, shallow, rapid landslides (debris avalanches, debris flows) usually initiate during individual intense or large storm events. Successfully predicting landslide hazards in large regions greatly depends on our ability to link meteorological conditions with various types and extents of slope failures. Four available methods for linking available weather and climate information to landslide initiation are discussed: (1) simple rainfall — landslide relationships; (2) multi-factor empirical assessment methods; (3) distributed, physically-based models; and (4) real-time warning systems. Each of these methods has certain strengths and weaknesses related to landslide hazard assessment. Of the land use practices that exacerbate landsliding, roads/trails and forest conversion to agriculture (typically associated with burning) exert the greatest impacts. Climate change scenarios that promote higher intensity storms, more rainfall, and vegetation with weaker root structure or less root biomass will likely increase landslide susceptibility; however, such impacts are currently speculative and will be difficult to unravel from anthropogenic effects.

Significant climatic variability is a common phenomenon in southern Africa. Frequent and persistent dry periods, unpredictable and variable rainfall and temperatures are considered normal climatic conditions. Additionally predictions of long-term climate changes for the sub-region suggest that by 2050 temperatures will be significantly higher and rainfall greatly reduced over extensive areas of southern Africa. Innovative drought hazard and land management responses are being implemented in the southern Africa sub-region. Best practices and clear shortcomings that have been identified and lessons learnt can feed into future response development. The adaptive response capacities of farmers, pastoralists and natural resource managers for example have to be strengthened in anticipation of worsening climatic conditions for crops and livestock productivity, conservation and sustainable use of biodiversity and land management, as a matter of priority. Concurrently capacities at the regional and national decision-making levels need also to be addressed.

Case examples from the sub-region demonstrate that intensive support to individual farmers and communities can significantly improve land management practices, responsiveness to climatic variability and improve livelihood security. Furthermore, it is clear however that pilot approaches need to be “up-scaleable”. Pilot studies may not be success stories if lessons learnt are not integrated in a wider systems context. It is also clear that local level interventions on their own will do little to address the issues of land degradation, desertification, sustainable land management, and drought hazard in an integrated way that reaches across to the regional and national decision making levels.

The cases selected provide examples of (i) an early warning system (EWS), and (ii) drought and/or desertification policy. These examples are being analysed based on experiences from southern Africa. Short narrative descriptions are provided and salient lessons learnt synthesised.

The Drought Monitoring Centre (DMC) is a specialized institution in climate diagnosis, prediction and applications for the Southern African Development Community (SADC) comprising 14 member states with well over 220 million inhabitants. SADC is largely semi-arid to arid. The SADC countries, therefore, experience recurrent vagaries of climatic extremes such as droughts, floods, tropical cyclones and tsunamis. Consequently, there are far-reaching negative impacts on socio-economic development of the member states and the well being of most of the inhabitants of the region. Impacts can easily exacerbate land degradation. The main objective of the DMC is to contribute to minimizing negative impacts of the climatic extremes on the socio-economic development of the region; and for the rational use of natural resources. This is achieved through the monitoring and diagnosis of near real-time climatic trends, and generating mediumrange (10–14 days) and long-range climate outlook products on monthly and seasonal (3–6 months) timescales. These outlook products are disseminated in timely manner to the communities of the SADC principally through the national Meteorological/Hydrological Services (NMHSs) regional organizations, relief and international development partner agencies. The provision of early warning for the formulation of appropriate strategies to combat the adverse effects of climate extremes affords greater opportunity to decision-makers for development of prudent plans for mitigating the negative impacts. The main activities of the DMC are described with suitable examples. The DMC is continuing to transform itself into a centre of excellence in climate analysis, prediction and applications with particular emphasis on the extremes across the SADC. It develops the capacity of the SADC NMHSs scientists on climate diagnosis and prediction; and users in climate applications.

Storing carbon (C) in soil as organic matter is not only a viable strategy to sequester CO from the atmosphere, but is vital for improving the quality of soil. This presentation describes (1) C sequestration concepts and rationale, (2) relevant management approaches to avoid land degradation and foster C sequestration, and (3) a summary of research quantifying soil C sequestration. The three primary greenhouse gases (CO, CH, and NO) derived from agriculture have increased dramatically during the past century. Conservation management practices can be employed to sequester C in soil, counter land degradation, and contribute to economic livelihoods on farms. Trees can accumulate C in perennial biomass of above-ground and below-ground growth, as well as in the deposition of soil organic matter. Minimal disturbance of the soil surface with conservation tillage is critical in avoiding soil organic C loss from erosion and microbial decomposition. Animal manures contain 40–60% C, and therefore, application to land promotes soil organic C sequestration and provides readily-available, recycled nutrients to crops. Green manures can be used to build soil fertility, often with leguminous plant species having symbiotic root associations with nitrogen-fixing bacteria. Grasslands have great potential to sequester soil organic C when managed properly, but can also be degraded due to overgrazing, careless management, and drought leading to accelerated soil erosion and undesirable species composition. Opportunities exist to capture and retain greater quantity of C from crop and grazing systems when the two systems are integrated. Fertilization is needed to achieve production goals, but when applied excessively it can lead to environmental pollution, especially when considering the energy and C cost of manufacture and transport. Agricultural conservation management strategies to sequester CO from the atmosphere into soil organic matter will also likely restore degraded land and/or avoid further land degradation.

Soil organic carbon (SOC) is vital for ecosystem and agro-ecosystem function. Any sustainable land management strategy should, therefore, include a consideration of long-term effects on SOC. In the future, we have the opportunity to adopt land management strategies that lead to greater C storage in the soil. However, to do so, we need consistent estimates of SOC stocks and changes under varying land use and climate change scenarios. A Global Environment Facility (GEF) project developed a generically applicable system (the GEFSOC Modelling System) for making such estimates. The system links two dynamic SOC models, designed for site scale applications (Century and RothC) and an empirical method, to spatial databases, giving spatially explicit results that allow geographic areas of change in SOC stocks to be identified. The system was developed using data from four contrasting eco-regions (The Brazilian Amazon, Jordan, Kenya and the Indian part of the Indo-Gangetic Plains). These areas were chosen, as they are located in regions previously underrepresented by soil C models. The system was then used to estimates SOC stocks and changes between 1990 and 2030 under likely land use change scenarios in each of the four regions. Losses in SOC of between 5 and 16 % were projected for each of the four areas over a 30-year period (2000–2030), driven by a range of factors including deforestation, overgrazing and conversion of grazing land to agriculture. Implications for sustainable land management and future land use policy are discussed for The Brazilian Amazon, Jordan, Kenya and the Indian Indo-Gangetic Plains.

In recent years there has been global concern over extreme weather events like droughts and floods which are linked to climate change. This concern has arisen from both observed and modeling studies that have indicated a possible climate change. Carbon dioxide which is principally linked to climate change, is a green house gas that has been blamed to be the driving force. However extreme weather events have been observed to cause land degradation in different parts of the globe. While studies on global scale show a significant increase in CO resulting in global warming and hence climate change, few regional studies have been carried out to demonstrate changes at the regional level. In this study trends and variability of CO, rainfall and NDVI over Tanzania were investigated to find out their association with land degradation.

Results reveal that CO exhibits a bimodal distribution, with a maximum in March and December, while minimum values are observed in January and May. This pattern can be associated with the annual cycle of vegetation cover. During maximum CO season, the land is bare and thus subjected to land degradation. NDVI showed a maximum in May and January/December for areas with bimodal rainfall and March/April for areas with unimodal rainfall. NDVI showed a minimum in March and October for bimodal areas and September/October for unimodal areas. A decreasing trend in NDVI is evident in most stations in different seasons over the country. This is a signal for land degradation and should be arrested. Rainfall, a very important factor in environmental sustainability, has proved to be decreasing in different seasons over the country. As it decreases it leaves the land dry, hinders vegetation and other hydro related factors. Decreased rainfall results in dry soil, decreased vegetation and hence land degradation. Excessive rainfall also contributes to land degradation by washing away loose and exposed soil in some parts of the country by floods. There is a need to arrest this situation for better land use.