scholarly journals Global-scale drought risk assessment for agricultural systems

Author(s):  
Isabel Meza ◽  
Stefan Siebert ◽  
Petra Döll ◽  
Jürgen Kusche ◽  
Claudia Herbert ◽  
...  

Abstract. Droughts continue to affect ecosystems, communities, and entire economies. Agriculture bears much of the impact, and in many countries it is the most heavily affected sector. Over the past decades, efforts have been made to assess drought risk at different spatial scales. Here, we present for the first time an integrated assessment of drought risk for both irrigated and rain-fed agricultural systems at the global scale. Composite hazard indicators were calculated for irrigated and rain-fed systems separately using different drought indices based on historical climate conditions (1980–2016). Exposure was analyzed for irrigated and non-irrigated crops. Vulnerability was assessed through a social-ecological systems perspective, using social-ecological susceptibility and lack of coping capacity indicators that were weighted by drought experts from around the world. The analysis shows that drought risk of rain-fed and irrigated agricultural systems displays heterogeneous pattern at the global level with higher risk for southeastern Europe, as well as northern and southern Africa. By providing information on the drivers and spatial patterns of drought risk in all dimensions of hazard, exposure, and vulnerability, the presented analysis can support the identification of tailored measures to reduce drought risk and increase the resilience of agricultural systems.

2020 ◽  
Vol 20 (2) ◽  
pp. 695-712 ◽  
Author(s):  
Isabel Meza ◽  
Stefan Siebert ◽  
Petra Döll ◽  
Jürgen Kusche ◽  
Claudia Herbert ◽  
...  

Abstract. Droughts continue to affect ecosystems, communities and entire economies. Agriculture bears much of the impact, and in many countries it is the most heavily affected sector. Over the past decades, efforts have been made to assess drought risk at different spatial scales. Here, we present for the first time an integrated assessment of drought risk for both irrigated and rainfed agricultural systems at the global scale. Composite hazard indicators were calculated for irrigated and rainfed systems separately using different drought indices based on historical climate conditions (1980–2016). Exposure was analyzed for irrigated and non-irrigated crops. Vulnerability was assessed through a socioecological-system (SES) perspective, using socioecological susceptibility and lack of coping-capacity indicators that were weighted by drought experts from around the world. The analysis shows that drought risk of rainfed and irrigated agricultural systems displays a heterogeneous pattern at the global level, with higher risk for southeastern Europe as well as northern and southern Africa. By providing information on the drivers and spatial patterns of drought risk in all dimensions of hazard, exposure and vulnerability, the presented analysis can support the identification of tailored measures to reduce drought risk and increase the resilience of agricultural systems.


2020 ◽  
Author(s):  
Isabel Meza ◽  
Stefan Siebert ◽  
Petra Döll ◽  
Jürgen Kusche ◽  
Claudia Herbert ◽  
...  

<p>Drought is a recurrent global phenomenon considered one of the most complex hazards with manifold impacts on communities, ecosystems, and economies. While many sectors are affected by drought, agriculture’s high dependency on water makes it particularly susceptible to droughts, threatening the livelihoods of many, and hampering the achievement of the Sustainable Development Goals. Identifying pathways towards more drought resilient societies by analyzing the drivers and spatial patterns of drought risk is of increasing importance for the identification, prioritization and planning of risk reduction, risk transfer and adaptation options. While major progress has been made regarding the mapping, prediction and monitoring of drought events at different spatial scales (local to global), comprehensive drought risk assessments that consider the complex interaction of drought hazards, exposure and vulnerability factors are still the exception.</p><p>Here, we present, for the first time, a global-scale drought risk assessment at national level for both irrigated and rain-fed agricultural systems. The analysis integrates (1) composite drought hazard indicators based on historical climate conditions (1980-2016), (2) exposure data represented by the harvest area of irrigated and rainfed systems, and (3) an expert-weighted set of social-ecological vulnerability indicators. The latter were identified through a systematic review of literature (n = 105 peer-reviewed articles) and expert consultations (n = 78 experts). This study attempted to characterize the average drought risk for the whole study period.</p><p>Results show that drought risk of rain-fed and irrigated agricultural systems display different heterogeneous patterns at the global level with higher risk for southeastern Europe, as well as northern and southern Africa. The vulnerability to drought highlights the relevance to increase the countries’ coping capacity in order to reduce their overall drought risk. For instance, the United States, which despite being highly exposed to drought hazard, has low socio-ecological susceptibility and sufficiently high coping capacities to reduce the overall drought risk considerably. When comparing irrigated and rain-fed drought hazard/exposure, there are significant regional differences. For example, the northern part  of Central Africa and South America have low hazard/exposure levels of irrigated crops, resulting in a low total risk, although high vulnerability characterize these regions. South Africa, however, has a high amount of rain-fed crops exposed to drought, but a lower vulnerability compared to other African countries. Further, the drivers of drought risk vary substantially across and within countries, calling for spatially targeted risk reduction and adaptation options.</p><p>Findings from this study underline the relevance of analyzing drought risk from a holistic and integrated perspective that brings together data from different sources and disciplines and based on a spatially explicit approach. Being based on open-source data, the approach allows for reproduction in varying regions and for different spatial scales, and can serve as a blueprint for future drought risk assessments for other affected sectors, such as water supply, tourism, or energy. By providing information on the underlying drivers and patterns of drought risk, this approach supports the identification of priority regions and provides entry points for targeted drought risk reduction and adaptation options to move towards resilient agricultural systems.</p>


2020 ◽  
Author(s):  
Heewon Jee ◽  
Hyeonju Kim ◽  
Daeho Kim ◽  
Tae-Ho Kang ◽  
Young-Oh Kim

<p>Numerous drought indices assess only hazard; however, very few indices take account into potential vulnerability and risk. Even though drought is one of the natural disasters that affect the socio-economic sphere, these indices do not reflect social capabilities. As an alternative, we proposed Drought Risk Index (DRI) developed by combining frameworks from Intergovernmental Panel on Climate Change(IPCC) and World Risk Index(WRI). DRI consists of three components such as Hazard, Exposure, Capacity. Hazard represents the reason factor causing damage and computed mainly by climate characteristics (e.g. monthly precipitation) while Exposure considers the objects exposed to disaster and calculates by the amount of the water demand (agricultural, industrial, and municipal sectors). In the case of Capacity, it indicates the ability of society to prepare or handle disasters and subdivides into adaptive and coping capacities; the adaptive capacity is calculated by institutional & financial abilities, and coping capacity by water resource facilities and response abilities. The proposed framework for DRI was tested under the specific focus on the local scale comparison of drought risk as a disaster at the Korean Peninsula. We aim at providing the basic tools for national drought management policies and plans.</p>


2013 ◽  
Vol 13 (19) ◽  
pp. 9917-9937 ◽  
Author(s):  
R. Locatelli ◽  
P. Bousquet ◽  
F. Chevallier ◽  
A. Fortems-Cheney ◽  
S. Szopa ◽  
...  

Abstract. A modelling experiment has been conceived to assess the impact of transport model errors on methane emissions estimated in an atmospheric inversion system. Synthetic methane observations, obtained from 10 different model outputs from the international TransCom-CH4 model inter-comparison exercise, are combined with a prior scenario of methane emissions and sinks, and integrated into the three-component PYVAR-LMDZ-SACS (PYthon VARiational-Laboratoire de Météorologie Dynamique model with Zooming capability-Simplified Atmospheric Chemistry System) inversion system to produce 10 different methane emission estimates at the global scale for the year 2005. The same methane sinks, emissions and initial conditions have been applied to produce the 10 synthetic observation datasets. The same inversion set-up (statistical errors, prior emissions, inverse procedure) is then applied to derive flux estimates by inverse modelling. Consequently, only differences in the modelling of atmospheric transport may cause differences in the estimated fluxes. In our framework, we show that transport model errors lead to a discrepancy of 27 Tg yr−1 at the global scale, representing 5% of total methane emissions. At continental and annual scales, transport model errors are proportionally larger than at the global scale, with errors ranging from 36 Tg yr−1 in North America to 7 Tg yr−1 in Boreal Eurasia (from 23 to 48%, respectively). At the model grid-scale, the spread of inverse estimates can reach 150% of the prior flux. Therefore, transport model errors contribute significantly to overall uncertainties in emission estimates by inverse modelling, especially when small spatial scales are examined. Sensitivity tests have been carried out to estimate the impact of the measurement network and the advantage of higher horizontal resolution in transport models. The large differences found between methane flux estimates inferred in these different configurations highly question the consistency of transport model errors in current inverse systems. Future inversions should include more accurately prescribed observation covariances matrices in order to limit the impact of transport model errors on estimated methane fluxes.


2013 ◽  
Vol 13 (4) ◽  
pp. 10961-11021
Author(s):  
R. Locatelli ◽  
P. Bousquet ◽  
F. Chevallier ◽  
A. Fortems-Cheney ◽  
S. Szopa ◽  
...  

Abstract. A modelling experiment has been conceived to assess the impact of transport model errors on the methane emissions estimated by an atmospheric inversion system. Synthetic methane observations, given by 10 different model outputs from the international TransCom-CH4 model exercise, are combined with a prior scenario of methane emissions and sinks, and integrated into the PYVAR-LMDZ-SACS inverse system to produce 10 different methane emission estimates at the global scale for the year 2005. The same set-up has been used to produce the synthetic observations and to compute flux estimates by inverse modelling, which means that only differences in the modelling of atmospheric transport may cause differences in the estimated fluxes. In our framework, we show that transport model errors lead to a discrepancy of 27 Tg CH4 per year at the global scale, representing 5% of the total methane emissions. At continental and yearly scales, transport model errors have bigger impacts depending on the region, ranging from 36 Tg CH4 in north America to 7 Tg CH4 in Boreal Eurasian (from 23% to 48%). At the model gridbox scale, the spread of inverse estimates can even reach 150% of the prior flux. Thus, transport model errors contribute to significant uncertainties on the methane estimates by inverse modelling, especially when small spatial scales are invoked. Sensitivity tests have been carried out to estimate the impact of the measurement network and the advantage of higher resolution models. The analysis of methane estimated fluxes in these different configurations questions the consistency of transport model errors in current inverse systems. For future methane inversions, an improvement in the modelling of the atmospheric transport would make the estimations more accurate. Likewise, errors of the observation covariance matrix should be more consistently prescribed in future inversions in order to limit the impact of transport model errors on estimated methane fluxes.


2019 ◽  
Vol 132 (3-4) ◽  
pp. 687-709
Author(s):  
Iris Schöllhorn ◽  
Alexander Houben ◽  
Brian Gertsch ◽  
Thierry Adatte ◽  
Ulianov Alexey ◽  
...  

Abstract The late Oligocene–early Miocene interval records a discernable episode of phosphorite formation, which is considered as the first of four main phosphogenic episodes during the late early and late Cenozoic. In order to better constrain the processes leading to widespread phosphorite formation we present new radiometric, geochemical, palynological, and sedimentological data from a drill core of the Roca Fosfórica Mexicana phosphorite mine at San Juan de la Costa, Baja California Sur (Mexico). In this region, phosphogenesis was enabled by the combination of high productivity and low sediment-accumulation rates due to enhanced upwelling and low detrital input related to regionally dry climate conditions. Phosphatic particles were formed in a shallow and well-oxygenated setting, subsequently concentrated by winnowing, and transported by gravity currents, which were mostly triggered by seismic activity. Following their deposition in a deeper and less well oxygenated setting pervasive phosphogenesis contributed to cementing the accumulated phosphatic grains. Correlation with global paleoclimate records suggests that this phosphogenic episode was linked to the expansion of the Antarctic ice sheet. Glacial weathering and the establishment of large-amplitude glacio-eustatic variations enhanced phosphorus supply on a global scale. Both glacial and interglacial phases participated in enhancing primary productivity in oceans, increasing the phosphorus flux into sediments, and favoring phosphogenesis, with glaciation being the prime cause. In addition, radiometric ages obtained in this study (28.62, 28.1, 27.19, 27.08, and 26.94 Ma) indicate that the onset of the late Oligocene–early Miocene phosphogenic episode was diachronous on a global scale with 2–3 m.y. older ages in the eastern Pacific in comparison to the Mediterranean and central Atlantic. This delay is explained by regional differences in paleoenvironmental and paleoceanographic conditions.


2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Nadia Bloemendaal ◽  
Hans de Moel ◽  
Sanne Muis ◽  
Ivan D. Haigh ◽  
Jeroen C. J. H. Aerts

Abstract Tropical cyclones (TC) are one of the deadliest and costliest natural disasters. To mitigate the impact of such disasters, it is essential to know extreme exceedance probabilities, also known as return periods, of TC hazards. In this paper, we demonstrate the use of the STORM dataset, containing synthetic TCs equivalent of 10,000 years under present-day climate conditions, for the calculation of TC wind speed return periods. The temporal length of the STORM dataset allows us to empirically calculate return periods up to 10,000 years without fitting an extreme value distribution. We show that fitting a distribution typically results in higher wind speeds compared to their empirically derived counterparts, especially for return periods exceeding 100-yr. By applying a parametric wind model to the TC tracks, we derive return periods at 10 km resolution in TC-prone regions. The return periods are validated against observations and previous studies, and show a good agreement. The accompanying global-scale wind speed return period dataset is publicly available and can be used for high-resolution TC risk assessments.


2019 ◽  
Author(s):  
Marina Peña-Gallardo ◽  
Sergio Martín Vicente-Serrano ◽  
Fernando Domínguez-Castro ◽  
Santiago Beguería

Abstract. Drought events are of great importance in most Mediterranean climate regions because of the diverse and costly impacts they have in various economic sectors and on the environment. The effects of this natural hazard on rainfed crops are particularly evident. In this study the impacts of drought on two representative rainfed crops in Spain (wheat and barley) were assessed. As the agriculture sector is vulnerable to climate, it is especially important to identify the most appropriate tools for monitoring the impact of the weather on crops, and particularly the impact of drought. Drought indices are the most effective tool for that purpose. Various drought indices have been used to assess the influence of drought on crop yields in Spain, including the standardized precipitation and evapotranspiration index (SPEI), the standardized precipitation index (SPI), the Palmer drought indices (PDSI, Z-Index, PHDI, PMDI), and the standardized Palmer drought index (SPDI). Two sets of crop yield data at different spatial scales and temporal periods were used in the analysis. The results showed that drought indices calculated at different time scales (SPI, SPEI) most closely correlated with crop yield. The results also suggested that different patterns of yield response to drought occurred depending on the region, period of the year, and the drought time scale. The differing responses across the country were related to season and the magnitude of various climate variables.


2020 ◽  
Vol 20 (3) ◽  
pp. 889-906
Author(s):  
Yaxu Wang ◽  
Juan Lv ◽  
Jamie Hannaford ◽  
Yicheng Wang ◽  
Hongquan Sun ◽  
...  

Abstract. Drought is a ubiquitous and recurring hazard that has wide-ranging impacts on society, agriculture and the environment. Drought indices are vital for characterising the nature and severity of drought hazards, and there have been extensive efforts to identify the most suitable drought indices for drought monitoring and risk assessment. However, to date, little effort has been made to explore which index (or indices) best represents drought impacts for various sectors in China. This is a critical knowledge gap, as impacts provide important ground truth information for indices used in monitoring activities. The aim of this study is to explore the link between drought indices and drought impacts, using Liaoning province (northeast China) as a case study due to its history of drought occurrence. To achieve this we use independent, but complementary, methods (correlation and random forest analysis) to identify which indices link best to drought impacts for prefectural-level cities in Liaoning province, using a comprehensive database of reported drought impacts in which impacts are classified into a range of categories. The results show that the standardised precipitation evapotranspiration index with a 6-month accumulation (SPEI6) had a strong correlation with all categories of drought impacts, while the standardised precipitation index with a 12-month accumulation (SPI12) had a weak correlation with drought impacts. Of the impact datasets, “drought-suffering area” and “drought impact area” had a strong relationship with all drought indices in Liaoning province, while “population and number of livestock with difficulty in accessing drinking water” had weak correlations with the indices. The results of this study can support drought planning efforts in the region and provide context for the indices used in drought-monitoring applications, so enabling improved preparedness for drought impacts. The study also demonstrates the potential benefits of routine collection of drought impact information on a local scale.


2017 ◽  
Vol 113 (5/6) ◽  
Author(s):  
Louise C. Gammage ◽  
Astrid Jarre ◽  
Charles Mather ◽  
◽  
◽  
...  

Variability on multiple temporal and spatial scales exposes fishers and fishing communities to multiple stressors. The impact and interplay of these stressors need to be considered to improve our understanding of social-ecological linkages if sustainable livelihoods are to be promoted. To this end, participant-led research was conducted in the small-scale traditional commercial linefishery of the southern Cape (South Africa) between Witsand and Mossel Bay. Knowledge and perceptions regarding stressors responsible for changes in the social-ecological system, which ultimately affect the fishers’ ability to fish successfully, were recorded using semi-formal interviews and focus groups with 50 participants. The results presented not only offer valuable insights into the day-to-day experiences of these fishers, but also expose knowledge gaps that exist in micro-scale interactions influencing the fishery system. An analysis of various stressors is presented, which includes the impacts of and responses to climate variability; challenges presented by fisheries policies and regulatory frameworks; social and economic considerations; inadequate infrastructure; and general political considerations. The development of a more comprehensive understanding of stressors that affect the social-ecological system at various scales provides valuable insights into a fishery system that is currently not well described, and provides the basis for analyses into vulnerability and resilience.


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