scholarly journals Mapping Vulnerability to Weather Extremes: Heat and Flood Assessment Approaches

Author(s):  
Zoé A. Hamstead ◽  
Jason Sauer

AbstractAssessing present social and biophysical conditions of communities that are at risk of injury due to extreme weather events is an important component of creating future visions of resilience. Spatial patterns of vulnerability to extreme events are manifestations of structural injustice that leave their mark on the built environment and in socio-spatial segregation patterns. Socio-spatial inequity often arises from development practices that favor particular racial and ethnic social groups over others. These segregation patterns are aligned with patterns of exposure to pollution, extreme weather events, and other types of environmental hazards. Spatial vulnerability assessments can be powerful tools for prioritizing where and how cities should make investments for mitigating the impacts of extreme events, and can provide an entry point for asking more fundamental questions about the processes that produce patterns of climate inequity, as well as how to avoid reproducing such processes in the future. Maps express uneven distributions of risk and manifestations of structural inequality in social–ecological–technological systems (SETS). They enable communities to visualize distributional injustice, consider ways in distributions that may be misaligned with cultural values, and develop adaptive practices toward climate justice. Here, we demonstrate approaches for assessing vulnerability to extreme flooding and heat, and show how vulnerability distributions are embedded in landscape patterns that produce uneven risk.

2021 ◽  
Author(s):  
Gennady Bracho Mujica ◽  
Peter Hayman ◽  
Victor Sadras ◽  
Bertram Ostendorf ◽  
Nicole Ferreira C. R. ◽  
...  

<p>Extreme events, such as drought, heat and/or frost are among the major weather-related causes of yield reduction and crop failure worldwide. Changes in the frequency and intensity of such weather extremes affect the shape and scale of yield distributions. Wheat growers, in Australia, are particularly vulnerable to climate due to its high variability. Risks of both, extremely high or low temperatures and water stress occurring simultaneously or at different crop stages within the growing season (May-October, e.g. frost mid-season, drought during the season and heat towards the end) often lead to yield reductions, or sometimes even to crop failure. In this study, we focused on assessing the frequency and impact of these relevant extreme weather events (i.e. drought, heat and frost) affecting wheat production in Australia. Specifically, we used a widely used and calibrated crop model (APSIM) to simulate wheat grain yield, and determine probability density functions (PDFs) of grain yield and crop failure. Chances of crop failure due to these extreme events are explored for the recent past (1991-2020) and the longer-term historical past (1901-1990). Key adaption strategies to minimise the impacts of these extreme events, and reduce crop failure risk are assessed in this study, including early sowing and cultivar choice. Our findings are in line with recent studies, indicating that drought and heat are major risk factors contributing to reduced yields or crop failure. However, due to the timing, frequency and impacts of frost events on wheat productivity, frost also remains a relevant risk for the wheat industry in Australia.</p>


2018 ◽  
Author(s):  
Junxi Zhang ◽  
Yang Gao ◽  
Kun Luo ◽  
L. Ruby Leung ◽  
Yang Zhang ◽  
...  

Abstract. The Weather Research and Forecasting model with Chemistry (WRF/Chem) was used to study the effect of extreme weather events on ozone in US for historical (2001–2010) and future (2046–2055) periods under RCP8.5 scenario. During extreme weather events, including heat waves, atmospheric stagnation, and their compound events, ozone concentration is much higher compared to non-extreme events period. A striking enhancement of effect during compound events is revealed when heat wave and stagnation occur simultaneously and both high temperature and low wind speed promote the production of high ozone concentrations. In regions with high emissions, compound extreme events can shift the high-end tails of the probability density functions (PDFs) of ozone to even higher values to generate extreme ozone episodes. In regions with low emissions, extreme events can still increase high ozone frequency but the high-end tails of the PDFs are constrained by the low emissions. Despite large anthropogenic emission reduction projected for the future, compound events increase ozone more than the single events by 10 % to 13 %, comparable to the present, and high ozone episodes are not eliminated. Using the CMIP5 multi-model ensemble, the frequency of compound events is found to increase more dominantly compared to the increased frequency of single events in the future over the US, Europe, and China. High ozone episodes will likely continue in the future due to increases in both frequency and intensity of extreme events, despite reductions in anthropogenic emissions of its precursors. However, the latter could reduce or eliminate extreme ozone episodes, so improving projections of compound events and their impacts on extreme ozone may better constrain future projections of extreme ozone episodes that have detrimental effects on human health.


2018 ◽  
Vol 2 (1) ◽  
pp. 9-24
Author(s):  
Edoardo Bertone ◽  
Oz Sahin ◽  
Russell Richards ◽  
Anne Roiko

Abstract A decision support tool was created to estimate the treatment efficiency of an Australian drinking water treatment system based on different combinations of extreme weather events and long-term changes. To deal with uncertainties, missing data, and nonlinear behaviours, a Bayesian network (BN) was coupled with a system dynamics (SD) model. The preliminary conceptual structures of these models were developed through stakeholders' consultation. The BN model could rank extreme events, and combinations of them, based on the severity of their impact on health-related water quality. The SD model, in turn, was used to run a long-term estimation of extreme events' impacts by including temporal factors such as increased water demand and customer feedback. The integration of the two models was performed through a combined Monte Carlo–fuzzy logic approach which allowed to take the BN's outputs as inputs for the SD model. The final product is a participatory, multidisciplinary decision support system allowing for robust, sustainable long-term water resources management under uncertain conditions for a specific location.


2021 ◽  
Author(s):  
S Vijayakumar ◽  
A.K. Nayak ◽  
N. Manikandan ◽  
Suchismita Pattanaik ◽  
Rahul Tripathi ◽  
...  

Abstract The study investigates trend in extreme daily precipitation and temperature over coastal Odisha, India. 18 weather indices (8 related to temperature and 10 related to rainfall) were calculated using RClimDex software package for the period 1980–2010 . Trend analysis was carried out using linear regression and non-parametric Mann-Kendall test to find out the statistical significance of various indices. Results indicated, a strong and significant trend in temperature indices while the weak and non-significant trend in precipitation indices. The positive trend in Tmax mean, Tmin mean, TN90p (warm nights), TX90p (warm days), diurnal temperature range (DTR), warm spell duration indicator (WSDI), consecutive dry days (CDD) indicates increasing the frequency of warming events in coastal Odisha. Similarly, positive trend in highest maximum 1-day precipitation (RX1), highest maximum 2 consecutive day precipitation (RX2), highest maximum 3 consecutive day precipitation (RX3), highest maximum 5 consecutive day precipitation (RX5), number of heavy precipitation days (≥64.5mm), number of very heavy precipitation days (≥124.5mm) and negative trend in the number of rainy days (R2.5mm), consecutive wet days (CWD) indicate changes toward the more intense and poor distribution of precipitation in coastal Odisha. The combined effect of precipitation and temperature extreme events showed negative effects on rice grain yield. With the increasing number of extreme events there was sharp decline in rice grain yield was observed in the same year in all the coastal districts. This study emphasizes the need for new technology/management practice to minimize the impacts of extreme weather events on rice yield.


PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0244512
Author(s):  
Luis Alexis Rodríguez-Cruz ◽  
Meredith T. Niles

Understanding how perceptions around motivation, capacity, and climate change’s impacts relate to the adoption of adaptation practices in light of experiences with extreme weather events is important in assessing farmers’ adaptive capacity. However, very little of this work has occurred in islands, which may have different vulnerabilities and capacities for adaptation. Data of surveyed farmers throughout Puerto Rico after Hurricane Maria (n = 405, 87% response rate) were used in a structural equation model to explore the extent to which their adoption of agricultural practices and management strategies was driven by perceptions of motivation, vulnerability, and capacity as a function of their psychological distance of climate change. Our results show that half of farmers did not adopt any practice or strategy, even though the majority perceived themselves capable and motivated to adapt to climate change, and understood their farms to be vulnerable to future extreme events. Furthermore, adoption was neither linked to these adaptation perceptions, nor to their psychological distance of climate change, which we found to be both near and far. Puerto Rican farmers’ showed a broad awareness of climate change’s impacts both locally and globally in different dimensions (temporal, spatial, and social), and climate distance was not linked to reported damages from Hurricane Maria or to previous extreme weather events. These results suggest that we may be reaching a tipping point for extreme events as a driver for climate belief and action, especially in places where there is a high level of climate change awareness and continued experience of compounded impacts. Further, high perceived capacity and motivation are not linked to actual adaptation behaviors, suggesting that broadening adaptation analyses beyond individual perceptions and capacities as drivers of climate adaptation may give us a better understanding of the determinants to strengthen farmers’ adaptive capacity.


Author(s):  
Friederike Otto

Natural disasters and extreme weather events have been of great societal importance throughout history and often brought everyday life to a catastrophic halt, in a way sometimes comparable to wars and epidemics, only without the lead time. Extreme weather events with large impacts serve as an anchor point of the collective memory of the population in the affected area. Every northern German of the right age remembers the storm surge of 1962 and where they were at the time and has friends or family effected by the event. The “dust bowl” of the 1930s with extensive droughts and heat waves shaped the life of a generation in the United States, and the Sahel droughts in the 1960s and 1970s led to famine and dislocation of population on a massive scale the region arguably never quite recovered from. Hurricane Hyian in 2013 is said to have directly influenced the outcome of the annual Conference of the Parties (COP) United Nation Framework Convention for Climate Change Negotiations in Warsaw, leading to the inclusion of a mechanism to deal with loss and damage from climate-related disasters. Though earthquakes are still fairly unpredictable on short timescales, this is not the case for weather events. Weather forecasts today are so good that we normally know the time and location of the landfall of a hurricane within a 100-mile radius days in advance. Improvements in the prediction of slow-onset events such as droughts (which depend on the rainfall over a large region and whole season) are less striking but have still improved dramatically in the late 20th and early 21st centuries. One of the major reasons for the large increase in the accuracy of weather forecasts is the exponential increase in computing power, which allows scientists to predict and study extreme weather events using complex computer models, simulating possible weather events under certain conditions to understand the statistics of and physical mechanisms behind extreme events. Extreme events are by definition rare and thus impossible to understand from historical records of weather observation alone. Despite the progress on our understanding of and ability to predict extreme weather events, substantial uncertainties remain. Two aspects are of particular importance. Firstly, we know that the climate is changing, having observed almost a one-degree increase in global mean temperature. However, global mean temperature doesn’t kill anyone, extreme weather events do. Their frequency and intensity is changing and will continue to change, but the extent of these changes depends on a host of both global and local factors. Secondly, whether or not a rare weather event leads to extreme impacts depends largely on the vulnerability and exposure of the affected societies. If these are high, even a perfectly forecasted weather event leads to disaster.


Author(s):  
Peter J. Webster ◽  
Jun Jian

The uncertainty associated with predicting extreme weather events has serious implications for the developing world, owing to the greater societal vulnerability to such events. Continual exposure to unanticipated extreme events is a contributing factor for the descent into perpetual and structural rural poverty. We provide two examples of how probabilistic environmental prediction of extreme weather events can support dynamic adaptation. In the current climate era, we describe how short-term flood forecasts have been developed and implemented in Bangladesh. Forecasts of impending floods with horizons of 10 days are used to change agricultural practices and planning, store food and household items and evacuate those in peril. For the first time in Bangladesh, floods were anticipated in 2007 and 2008, with broad actions taking place in advance of the floods, grossing agricultural and household savings measured in units of annual income. We argue that probabilistic environmental forecasts disseminated to an informed user community can reduce poverty caused by exposure to unanticipated extreme events. Second, it is also realized that not all decisions in the future can be made at the village level and that grand plans for water resource management require extensive planning and funding. Based on imperfect models and scenarios of economic and population growth, we further suggest that flood frequency and intensity will increase in the Ganges, Brahmaputra and Yangtze catchments as greenhouse-gas concentrations increase. However, irrespective of the climate-change scenario chosen, the availability of fresh water in the latter half of the twenty-first century seems to be dominated by population increases that far outweigh climate-change effects. Paradoxically, fresh water availability may become more critical if there is no climate change.


2020 ◽  
Author(s):  
Assaf Hochman ◽  
Pinhas Alpert ◽  
Hadas Saaroni ◽  
Tzvi Harpaz ◽  
Joaquim G. Pinto ◽  
...  

<p>Extreme weather events have long been considered challenging to predict. It is likely that global warming will trigger extreme weather in many regions of the globe and especially over the Mediterranean ´hot spot´. Therefore, extreme weather events have been selected as one of the grand challenges of the World Climate Research Program.</p><p>The intrinsic predictability of a weather system, or any dynamical system, depends on its persistence and its active number of degrees of freedom. Recent developments in dynamical systems theory allow to compute these metrics for atmospheric configurations (1). In most of the mid-latitudes, synoptic scale patterns exert a strong control on regional weather, thus, stimulating a broad interest, especially in weather forecasting. Recently, we have integrated the dynamical systems approach with a synoptic classification algorithm over the Eastern Mediterranean (2).  It was shown that the dynamical systems perspective provides an extremely informative tool for evaluating the predictability of synoptic patterns and especially of weather extremes.</p><p>The novel perspective, which leverages a dynamical systems approach to investigate the predictability of extreme weather events, outlines a new avenue of research that may be fruitfully applied at operational weather and climate forecasting services in the Mediterranean Region and around the globe.</p><p><strong>References</strong></p><ol><li>Faranda D, Messori G, Yiou P. 2017. Dynamical Proxies of North Atlantic Predictability and Extremes. Scientific Reports <strong>7</strong>, 412782017b. DOI: 10.1038/srep4127</li> <li>Hochman A, Alpert P, Harpaz T, Saaroni H, Messori G. 2019. A New Dynamical Systems Perspective on Atmospheric Predictability; Eastern Mediterranean Weather Regimes as a Case Study. Science Advances <strong>5</strong>. DOI: 10.1126/sciadv.aau0936</li> </ol>


2004 ◽  
Vol 85 (5) ◽  
pp. 697-708 ◽  
Author(s):  
Richard J. Murnane

Extreme weather events produce some of the most deadly and costly natural disasters and are a major concern of the catastrophe reinsurance industry. For example, in 1992 Hurricane Andrew caused over $20 billion (in 2002 U.S. dollars) in insured losses, the largest loss on record due to a natural disaster. In addition, 26 of the top 30 insured losses were produced by extreme weather events, mainly landfalling hurricanes and typhoons and European windstorms. A better understanding of how extreme events vary with climate would benefit the reinsurance industry and society. The Risk Prediction Initiative hosted a workshop on Weather Extremes and Atmospheric Oscillations that examined how extreme meteorological events of interest to the reinsurance industry are influenced by the quasi-biennial oscillation (QBO), the Arctic Oscillation (AO), and the Madden–Julian oscillation (MJO). Workshop participants concluded that the stratosphere is much more relevant to predictions that aid the reinsurance industry than is generally recognized and that there is mutual interest in fostering research on the relationship between the stratospheric circulation and extreme weather events. A preliminary science–business research agenda, based on presentations and discussions during and after the workshop, highlights four areas of mutual interest to scientists and insurers. The research areas focus mainly on understanding how the QBO, AO, and MJO influence the frequency and intensity of extreme events, with particular emphasis on tropical cyclones and European windstorms. An awareness of how the catastrophe reinsurance industry operates provides insights into why specific research areas were chosen. For example, the reinsurance industry operates on the basis of annual contracts, most of which are renewed on 1 January. Thus, although skillful forecasts at any lead are of interest, skillful forecasts of extreme events are of greatest value when made in the final quarter of a calendar year.


2016 ◽  
Vol 23 (1) ◽  
pp. 59-69 ◽  
Author(s):  
Zbigniew W. Kundzewicz

Abstract The damage (in real terms after adjusting for inflation) caused by extreme weather events globally has increased dramatically over the past few decades. This is a result of an increase in the amplitude and frequency of weather extremes, as well as of human factors causing a widespread increase in levels of exposure and vulnerability. There are a number of reasons to consider that, in many regions of the globe, weather extremes (e.g. heat waves, droughts, forest fires, intense rainfall, floods and landslides) are becoming both yet more extreme and more frequent. Projections for the future based on climate and impact models point to a further strengthening of this trend. There has already been an increase in rainfall intensity in conditions of a warmer climate, and a continuation of this trend is expected, with adverse consequences for flood risk. However, the development of flood-prone areas and increase in damage potential are often the dominant factors underpinning growing flood damage and flood risk. In warmer climates, an increased risk of river and flash flooding caused by heavy rainfall, as well as an increasing risk of coastal flooding associated with sea level rise can be expected over large areas. By the same token, a reduction in the risk of snowmelt flooding events is projected in the warmer climate. Projections also indicate an increased risk of drought in many areas. The projections for climate change in Poland point to several risks associated with an increase in the frequency, intensity and severity of weather extremes (heat waves, intensive rainfall, flooding and landslides, coastal surges, drought during the growing season and winter, strong winds and pathogens associated with warming). Heat waves will become more frequent, more intense and more troublesome for the ageing population of Poland.


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