[en] Drought is a major issue that humanity confronts with and due to its vast ramifications, it is also most difficult to solve. Being a natural phenomenon, it has various manifestations which scalars have categorized into meteorological, agricultural, hydrological, environmental and others, in order to better define and understand this phenomenon. Several drought indices have been proposed by different scholars for measuring it which take rainfall, temperature, sun shining and other features into account. This of course, led to a variety of interpretations which makes the phenomenon even more difficult to size up and quantify its devastating effects on a longterm scale. The seven indexes this paper makes use of, for calculating drought are: N. Topor index, De Martonne index, Domuta hydroheliothermal index, Selianinov hydrothermal index, Palfai drought index and Lang rain index. In this paper, the case study conducted for Banloc in the 1980-2014 period reveals alternating wet and dry periods which do not pose any threat of aridization or desertification soon. However, a constant monitoring is imposed for these phenomena not to occur, made by the authorized law enforcement together with specialists from various fields. (paper)

[en] Farmer household livelihood choice has been critical in ecosystem and natural resource sustainability in developing countries. This paper investigates the choices of farmer household livelihood in a Karst environment in China by using a multinomial logistic regression model to analyze 676 farmer household questionnaire responses from 6 counties in Anshun City, Guizhou Province. The results show that factors such as land quality, regional accessibility, government policies, and farmer households' characteristics have significant effect on farmer household livelihood choices. Even though farmers are unwilling to live in areas of rocky desertification and soil erosion, the proportion of those who live in those areas is high, because alternatives are limited by environment conditions and farmer households' situations. Good regional traffic accessibility facilitates farmer households’ part-time non-agricultural employment. Meanwhile, the Rocky Desertification Control Project increases migrant laborers. The study suggests that government policies diversify the choices of farmer household livelihoods in different eco-environment regions.

[en] Guizhou Province in China is a typical karst region. Because of its fragile environment, the restoration of the vegetation and environment of this province is highly important. In this study, biomass expansion factors and average biomass were used to measure the forest biomass, which we used to fit a logistic regression between carbon density and forest age for each forest type based on a 2010 forest inventory in Guizhou. In combination with the Guizhou afforestation plan, the model predicts the trends in carbon storage, carbon density and carbon sequestration rate. In addition, we used grey relational analysis and multiple regression to explore the effects of afforestation, forest age and site conditions. The model demonstrated, first, that forest carbon storage in Guizhou is predicted to gradually increase from 203.62 TgC in 2010 to 575.99 TgC in 2050; second, forest carbon density is also predicted to gradually increase from 29.32 MgC•hm-2 in 2010 to 55.64 MgC•hm-2 in 2050; and finally, afforestation is predicted to significantly improve the forest carbon sequestration rate from 0.72 MgC•hm-2•a-1 in 2010 to 0.77 MgC•hm-2•a-1 in 2050. The expansion of forest area and the increase in forest age resulted from afforestation and promoted forest carbon sinks. Forest carbon sequestration increased significantly with increasing forest age but was strongly constrained by rocky desertification. In addition to afforestation, we suggest that improving the forest carbon sink in Guizhou should put a greater emphasis on approaches such as fully exploiting the carbon sequestration capacity of the existing forests, decreasing disturbance to the existing forests, improving the forest age structure and better managing rocky desertification. (author)

[en] The effects of climate change, including increasingly severe droughts, shrinking glaciers, changes in the range of plants and animals and rising sea levels, are already being realized, and vary by region. A fragile state is one where the state government is not able to, or chooses not to, provide the basic essentials to its people. This paper establishes the Fragile Evaluation Model based on Fragile State Index (FSI) to determine a country’s fragility and measure the impact of climate change. We determine the indicators that affect the national climate and quantify them to establish the Climatic Stress Model. Then, based on this model, we combine the climactic stress index with 12 sub-indicators from FSI to develop the Fragile Evaluation Model. Next, we select Yemen as one of the top 10 most fragile countries from the FSI to determine how climate change increases the country’s fragility. The result shows that Yemen suffers a lot from strong wind and desertification which adds to the fragility of country. (paper)

[en] Aeolian desertification is one of the primary factors that impede sustainable socio-economic development in China’s Tibet Autonomous Region. To develop a set of science-based preventive measures, it is first necessary to understand the temporal and spatial distribution of aeolian desertified land (ADL) and the driving factors responsible for its creation. In this study, we used Landsat MSS, TM, and ETM data from the 1970s, 1990s, 2000s, and 2010s to classify ADL into different types, and distribution of ADL in the Tibet Autonomous Region was described. The results showed that by 2010, ADL covered an area of 203,476 km² and was primarily (91.5 %) the gravel surface (gobi) type. The area of ADL and desertification severity increased from the south-east to the north-west. During the study period, aeolian desertification experienced three development stages: initial rapid development, subsequent slower development, and a final period of slow reversal. The area of ADL increased by a total of 3134 km² from 1977 to 2010, but the temporal trends differed among the three main sub-regions of Tibet. Increasing drought and irrational human activities have caused an expansion of desertification in some areas, whereas ecological restoration projects contributed to the reversal of desertification in others.

[en] Highlights: • LDN is not a social norm and its framing is yet to recognise how people structure their thinking about neutrality issues. • SES-based LDN approach reveals what it means to consider humans as part of nature in the pursuit of LDN. • SES science and practice can inspire progress towards identifying appropriate LDN baselines for tracking change. - Abstract: Viewing humans as drivers of change operating outside the natural environment is unhelpful for defining interventions that effectively manage change and complexity. Indeed, there is now broad agreement that environmental governance needs to consider integrated social-ecological systems (SES) in order to tackle the world’s grand challenges of land degradation. This requires a more differentiated, innovative approach that considers how changes in SES shape the functioning of land systems as a whole, and the synergies and trade-off these changes may produce. In this study, we identify and discuss some of the ways SES science and practice can inspire progress towards land degradation neutrality (LDN) outcomes in an integrated manner, through synthesis of literature and relevant documents related to the United Nations Convention to Combat Desertification (UNCCD). We do these by considering: (i) how LDN has been approached to date and the challenges likely to undermine progress towards achieving it; and (ii) an SES-based LDN approach relevant to the neutrality agenda, in particular, by describing how LDN might be thought of differently through an SES lens. We argue that an SES approach focusing on: (i) “people as part of nature”, not “people and nature”; and (ii) the frame of reference against which neutrality can be assessed across temporal and spatial dimensions, is necessary to both inform policy and guide actions of the different groups involved in avoiding and combating land degradation. Such an (integrated) approach adds a dimension (to achieving neutrality goals) not previously explored in sustainable land management and LDN research. Important next steps in operationalising the SES-based LDN approach involve empirical and field case studies, requiring interdisciplinary, mixed method techniques.

[en] Highlights: • Afforestation area increased by 73,764.31 km² in sandy regions of northern China, from 2003 to 2017. • Afforestation water footprint (AWF) showed high heterogeneity and ranged from 0 to 58.9 m³/gC. • Potential evapotranspiration dominated AWF at national scale but major factors differed at sub-region level • The interactions between different factors had higher impact on AWF than single factor. To mitigate desertification and alleviate soil erosion, a wide range of ecological restoration initiatives have been implemented in arid and semi-arid areas, the water consumption of ecological projects and driving mechanisms received increasing attention to balance economy development and ecology restoration at different scales. In this study, the water footprint (WF) was employed as an indicator of water consumption by afforestation, and trend analysis, texture classification and geographical detector methods were used to identify the afforestation area and assess the influences of natural and human factors on the afforestation WF in the desert regions of northern China. The results revealed four major findings. (1) The afforestation area increased by 73,764.31 km², from 2003 to 2017, accounting for 2.42% of the study area. (2) On average, the afforestation WF increased from east to west, ranging from 0 to 58.9 m³/gC, indicating its high spatial heterogeneity. (3) Potential evapotranspiration was the dominant factor influencing the afforestation WF, explaining 20.4% of the variation in afforestation WF. (4) The explanatory power of natural and human factors was disparate at the different scales and the interactions between different factors had higher impact than that of single factors. These findings could provide valuable information to support more sustainable ecological restoration science and interventions in arid and semi-arid areas.

[en] Highlights: • Land degradation and wealth were analysed at various planning scales in Italy. • Land sensitivity to degradation increases more rapidly in economically advanced contexts. • Linear models are the best fit at all planning scales. • Developmental policies have less impact on land degradation in specific local contexts. • Multi-scale regressions provided insights into complex ecological-economic processes. This study examines the intrinsic relationship between land degradation and the accumulation of wealth at various planning scales in Italy, a desertification hotspot in Southern Europe. Local development was scrutinized at four planning scales (administrative regions, provinces, economic districts, and municipalities) to verify if land sensitivity to degradation increases over time more rapidly in economically advanced contexts. Land sensitivity to degradation increased between the early 1990s and the early 2010s contrary to the level of income per-capita based on linear, squared, cubic, and fourth-grade polynomial specifications. Spatially implicit and explicit statistical approaches indicate linear models are the best fit at all planning scales. The income-land degradation relationship was negative, showing the role of both centralized and decentralized planning scales, and suggesting that developmental policies may have less impact on land degradation in specific territorial contexts. More suited local models displayed a negative socio-economic development impact in more affected Southern districts. Checking for spatial heterogeneity, multi-scale regressions provided insights into complex ecological-economic processes whilst also evaluating the impact of regional development at different planning levels contributing to design scalable mitigation policies against desertification.

[en] The Tarim Basin is a typical arid area and has the world’s most severe desertification of natural and semi-natural land due to limited water resources. However, knowledge about the impacts of changes in water resources on the spatio-temporal dynamics of natural and semi-natural land is still limited. We analyzed the spatio-temporal changes in natural and semi-natural land and the associations with desertification in the Tarim Basin during the period 1990–2015. We then investigated the changes in water resources and the consequent impacts on the spatio-temporal changes of natural and semi-natural land by integrating Gravity Recovery and Climate Experiment territorial water storage data and field observations. The results showed that a total area of 10.32 × 10³ km² of natural and semi-natural land was converted to desert during the period 1990–2015. Desert vegetation type and saline type were the natural and semi-natural land types most sensitive to conversion to desert. The area of natural and semi-natural land decreased by 0.83% every year, and the proportion of desertified land was 34.79% on average during the period 2000–2010; this is less than for the period 1990–2000 (1.14% yr⁻¹ and 52.01%) due to increased availability of water resources from the water conveyance program. However, the rate of decrease of natural and semi-natural land area (0.93% yr⁻¹) and the proportion of desertified land (58.88%) rose again during the period 2010–2015 due to the rapid decrease in water resources. During the period 2000–2015, the rate of loss of natural and semi-natural land area (7.89%) in the region with decreased water resources was about twice that in the region with increased water resources (3.88%), highlighting the critical role of water resources in maintaining natural and semi-natural land and slowing desertification. (letter)

[en] The human-induced desiccation of the Aral Sea has generated large amounts of salt dust and has been posing a great threat to local ecological environment and human health. Monitoring its land cover changes is essential to obtaining information about the desertification process and dynamics of potential salt/sand dust source. To this end, long-term Landsat imagery was applied for the land use/cover change analysis based on support vector machine approach. The land cover distribution of the study area for 1977, 1987, 1996, 2006 and 2015 was mapped. In addition, the Markov–cellular automata integrated approach was used to predict the land cover change in 2015 and project changes in 2025 by extrapolating current trends. The classification results revealed that water surface of the Aral Sea shrunk by more than 66%, leading to the dramatic expanding of the salt soil and bare area. Change detection analysis indicated a serious land degradation trend as well as a major land cover evolution mode in the Aral Kum that could predict shifts in dust composition. The Markov–cellular automata technique was successful in predicting land cover distribution in 2015, and the projected land cover for 2025 revealed more desertification of the landscape with potential expansion in the salt soils and bare area. It is worth noting that the vegetation cover of the region represented an obvious increase in recent years that may be a good signal of ecological recovery.