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Giuliano Di Baldassarre
Fatalities and economic losses caused by floods are dramatically increasing in many regions of the world, and there is serious concern about future flood risk given the potentially negative effects of climatic and socio-economic changes. Over the past decades, numerous socio-economic studies have explored human responses to floods—demographic, policy and institutional changes following the occurrence of extreme events. Meanwhile, many hydrological studies have investigated human influences on floods, such as changes in frequency, magnitude, and spatial distribution of floods caused by urbanization or by implementation of risk reduction measures. Research in socio-hydrology is providing initial insights into the complex dynamics of risk resulting from the interplay (both responses and influences) between floods and people. Empirical research in this field has recently shown that traditional methods for flood risk assessment cannot capture the complex dynamics of risk emerging from mutual interactions and continuous feedback mechanisms between hydrological and social processes. It has also been shown that, while risk reduction strategies built on these traditional methods often work in the short term, they might lead to unintended consequences in the longer term. Besides empirical studies, a number of socio-hydrological models have been recently proposed to conceptualize human/flood interactions, to explain the dynamics emerging from this interplay, and to explore possible future trajectories of flood risk. Understanding the interplay between floods and societies can improve our ability to interpret flood risk changes over time and contribute to developing better policies and measures that will reduce the negative impacts of floods while maintaining the benefits of hydrological variability.
Scott C. Hagen, Davina L. Passeri, Matthew V. Bilskie, Denise E. DeLorme, and David Yoskowitz
The framework presented herein supports a changing paradigm in the approaches used by coastal researchers, engineers, and social scientists to model the impacts of climate change and sea level rise (SLR) in particular along low-gradient coastal landscapes. Use of a System of Systems (SoS) approach to the coastal dynamics of SLR is encouraged to capture the nonlinear feedbacks and dynamic responses of the bio-geo-physical coastal environment to SLR, while assessing the social, economic, and ecologic impacts. The SoS approach divides the coastal environment into smaller subsystems such as morphology, ecology, and hydrodynamics. Integrated models are used to assess the dynamic responses of subsystems to SLR; these models account for complex interactions and feedbacks among individual systems, which provides a more comprehensive evaluation of the future of the coastal system as a whole. Results from the integrated models can be used to inform economic services valuations, in which economic activity is connected back to bio-geo-physical changes in the environment due to SLR by identifying changes in the coastal subsystems, linking them to the understanding of the economic system and assessing the direct and indirect impacts to the economy. These assessments can be translated from scientific data to application through various stakeholder engagement mechanisms, which provide useful feedback for accountability as well as benchmarks and diagnostic insights for future planning. This allows regional and local coastal managers to create more comprehensive policies to reduce the risks associated with future SLR and enhance coastal resilience.
Michael Wehner, Federico Castillo, and Dáithí Stone
Extremely high air temperatures are uncomfortable for everyone. For some segments of the population, they can be deadly. Both the physical and societal aspects of intense heat waves in a changing climate warrant close study. The large-scale meteorological patterns leading to such events lay the framework for understanding their underlying causal mechanisms, while several methods of quantifying the combination of heat and humidity can be used to determine when these patterns result in stressful conditions. We examine four historic heat waves as case studies to illustrate differences in the structure of heat waves and the variety of effects of extreme heat on humans, which are characterized in terms of demographic, geographic, and socioeconomic impacts, including mortality and economic ramifications.
Weather station data and climate model projections for the future point to an increase in the frequency and intensity of extreme heat waves as the overall climate gets warmer. Changes in the radiative energy balance of the planet are the principal culprit behind this increase. Quantifying changes in the statistics of extreme heat waves allows for examination of changes in their potential contribution to human health risk. Large-scale mortality during heat waves always occurs within a context of other factors, including public health policy, rural and urban management and planning, and cultural practices. Consequently, the impacts of heat waves can be reduced, and may in many places be manageable into the future, through implementation of such measures as public health warning systems, effective land management, penetration of air conditioning, and increased monitoring of vulnerable or exposed individuals. Given the potential for severe impacts of the more intense heat waves that are virtually certain to occur in the warmer future, it is critical that both the physical and social sciences be considered together to enable society to adapt to these conditions.
Pedro J. Restrepo
The U.S. National Weather Service (NWS) is the agency responsible for flood forecasting. Operational flow forecasting at the NWS is carried out at the 13 river forecasting centers for main river flows. Flash floods, which occur in small localized areas, are forecast at the 122 weather forecast offices.
Real-time flood forecasting is a complex process that requires the acquisition and quality control of remotely sensed and ground-based observations, weather and climate forecasts, and operation of reservoirs, water diversions, and returns. Currently used remote-sense observations for operational hydrologic forecasts include satellite observations of precipitation, temperature, snow cover, radar observations of precipitation, and airborne observations of snow water equivalent. Ground-based observations include point precipitation, temperature, snow water equivalent, soil moisture and temperature, river stages, and discharge. Observations are collected by a number of federal, state, municipal, tribal and private entities, and transmitted to the NWS on a daily basis.
Once the observations have been checked for quality, a hydrologic forecaster uses the Community Hydrologic Prediction System (CHPS), which takes care of managing the sequence of models and their corresponding data needs along river reaches. Current operational forecasting requires an interaction between the forecaster and the models, in order to adjust differences between the model predictions and the observations, thus improving the forecasts. The final step in the forecast process is the publication of forecasts.
Between 50 and 70 volcanoes erupt each year—just a fraction of the 1,000 identified volcanoes that may erupt in the near future. When compared with the catastrophic loss of lives and property resulting from typhoons, earthquakes, and floods, losses from the more infrequent but equally devastating volcanic eruptions are often overlooked. Volcanic events are usually dramatic, but their various effects may occur almost imperceptibly or with horrendous speed and destruction. The intermittent nature of this activity makes it difficult to maintain public awareness of the risks. Assessing volcanic hazards and their risks remains a major challenge for volcanologists.
Several generations ago, only a small, international fraternity of volcanologists was involved in the complex and sometimes dangerous business of studying volcanoes. To understand eruptions required extensive fieldwork and analysis of the eruption products—a painstaking process. Consequently, most of the world’s volcanoes had not been studied, and many were not yet even recognized. Volcano research was meagerly supported by some universities and a handful of government-sponsored geological surveys. Despite the threats posed by volcanoes, few volcanological observatories had been established to monitor their activity.
Volcanology is now a global venture. Gone are the days when volcanologists were educated or employed chiefly by the industrial nations. Today, volcanologists and geological surveys are located in many nations with active volcanoes. Volcanological meetings, once limited to geologists, geophysicists, and a smattering of meteorologists and disaster planners, have greatly expanded. Initially, it was a hard sell to convince volcanologists that professionals from the “soft sciences” could contribute to the broad discipline of volcanology. However, it has become clear that involving decision makers such as urban planners, politicians, and public health professionals with volcanologists is a must when exploring and developing practical, effective volcanic-risk mitigation.
Beginning in 1995, the “Cities on Volcanoes” meetings were organized to introduce an integrated approach that would eventually help mitigate the risks of volcanic eruptions. The first conference, held in Rome and Naples, Italy, encompassed a broad spectrum of topics from the fields of volcanology, geographic information systems, public health, remote sensing, risk analysis, civil engineering, sociology and psychology, civil defense, city management, city planning, education, the media, the insurance industry, and infrastructure management. The stated mission of that meeting was to “better evaluate volcanic crisis preparedness and emergency management in cities and densely populated areas.” Since that meeting nearly twenty years ago, Cities on Volcanoes meetings have taken place in New Zealand, Hawaii, Ecuador, Japan, Spain, and Mexico; the 2014 venue was Yogyakarta, Indonesia. The significant and rewarding result of these efforts is a growing connection between basic science and the practical applications needed to better understand the myriad risks as well as the possible hazard mitigation strategies associated with volcanic eruptions.
While we pursue this integrated approach, we see advances in the technologies needed to evaluate and monitor volcanoes. It is impossible to visit all the world’s restless volcanoes, let alone establish effective monitoring stations for most of them. However, we can now scrutinize their thermal signatures and local ground deformation with instruments on earth-observing satellites. When precursory activity is detected by remote sensors in an area where a population is at risk, teams can be deployed for ground-based monitoring of that activity. In addition, by evaluating a volcano’s past eruption history, scientists can forecast both future activity and the possible risks to inhabitants. Using physics-based modeling, there is a better understanding of the types and severity of potential eruption phenomena such as pyroclastic flows, ash eruptions, gaseous discharge, and lava flows. Field observations of changes indicating an imminent eruption are now monitored with geophysical and geochemical instrumentation that is smaller, tougher, and more affordable.
Volcanology has evolved into a broader, integrated scientific discipline, but there is much still to be accomplished. The new generation of volcanologists, who have the advantage of knowing the theoretical underpinnings of volcanic activity, can now turn to the allied endeavor of reducing risk—their aspiration for the 21st century.
This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Natural Hazard Science. Please check back later for the full article.
Spatial and urban planning are acknowledged as important tools and processes that influence exposure to natural and technical hazards and risk accumulation, as well as risk and vulnerability reduction. Even though natural hazards (such as floods) and technical hazards have been discussed in spatial and urban planning for quite some time in various countries and regions, only in a very few cities and regions has there been a sufficient and systematic approach to establish risk management as part of the planning task within the field of spatial planning and urban land-use planning. Risk management strategies in spatial and urban planning have often been strengthened after major crises, such as severe fires in the middle ages in cities in Europe, or after major floods or hurricanes in North America, Asia, and Latin America, as well as Europe and Africa. In this context, risk management is understood as a cluster of concrete and practical strategies and actions on how to handle risks, and in terms of spatial and urban planning, including those risks that are of spatial importance or significant with regard to planning processes.
Vulnerability is complex because it involves many characteristics of people and groups that expose them to harm and limit their ability to anticipate, cope with, and recover from harm. The subject is also complex because workers in many disciplines such as public health, psychology, geography, and development studies (among others) have different ways of defining, measuring, and assessing vulnerability. Some of these practitioners focus on the short-term identification of vulnerability, so that maps and lists of people living “at risk” can be generated and used by authorities. Others are more concerned with reasons why some people are more vulnerable when facing a hazard or threat than others. Professionals working at the scale of localities are interested in methods that bring out residents’ own knowledge of hazards and help them to cooperate with each other to find ways of reducing risk. There are some interpretations of vulnerability that seek its root cause in the creation of risk by political and economic systems that make investment and locational decisions for the benefit of small elites without regard for how these decisions affect the majority. Finally, whatever success there may be in treating vulnerability in any of the ways just mentioned, it will always be a part of the human condition, and this fact in itself is puzzling.
Janine M. H. Selendy
This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Natural Hazard Science. Please check back later for the full article.
Increasingly frequent and intense extreme climatic events are wreaking havoc in regions all over the world, not only causing immediate death and destruction, but also destroying prospects for attaining the most basic of human needs—water, food, and secure shelter. What is more, the problems brought about by extreme events are often exacerbated by ecosystem destruction due to human activities. This is a universal, global problem. Children are the most vulnerable. Insufficient and polluted water afflicts a third or more of the people of the world causing over a billion illnesses, illnesses often related to 2.5 billion people lacking sanitation, and illnesses often combined with malnutrition. In 2013, 783 million people lacked clean water. Procurement and allocation of water are major problems in rural and urban areas. More than 70% of fresh water is used for irrigation of crops, much of it lost to evaporation, and much resulting in build up of salinization on bordering farmland. Cities, now home to 54% of the world’s population, often lack adequate infrastructure to provide clean drinking water. In the United States, cities are faced with contaminated water from their pipes, as in Flint Michigan and in New Jersey schools. Naturally occurring water pollutants that can harm ecosystems, aquatic organisms, and humans are becoming more prevalent due to physical developments and climate change. For example, toxic cyanobacteria, also known as blue-green algae, in coastal and inland waters are causing mortality and morbidity in humans, livestock, and wild animals. Over the last three decades, one of these bacteria, C. raciborskii has been increasingly recognized as a public health exigency for drinking water supplies across all inhabited continents.
While food today is more readily available worldwide than in the past, nearly a billion people go hungry. The roughly billion people who rely on fish from the oceans are faced with dwindling harvests due to overfishing, warming waters that harm coral reef breeding grounds, and the loss of mangrove spawning grounds. Crops and livestock are hurt by climate change. Productivity is diminished by reliance on monoculture, poor storage, and transportation problems. The situation is drastically worsened by unnecessary waste and spoilage. The world is producing more than enough food, according to the Food and Agriculture Organization of the United Nations, which says that “Recovering just half of what is lost or wasted” alone could feed the world. Regarding spoilage, aflatoxins—poisonous, cancer-causing chemicals produced by certain molds—are found in spoiled food, including staples such as corn, millet, peanuts, and wheat, affecting not only immediate consumers, but also those who buy processed food. Droughts causing dead livestock and wilted crops have driven millions from their homes and farmland, as happened in Syria. Subsequent conflict led millions of Syrians to become both political and climate refugees, living in refugee camps and traveling thousands of treacherous miles to resettle. Poverty, whether experienced in slums, refugee camps, or other rural and urban settings, causes lack of land and shortages of material for soundly built housing that can withstand weather changes, even screens to help reduce exposure to mosquitoes, flies, and other disease vectors. The nearly quarter of the world’s urban population who live in slums live mostly in overcrowded, unsafe shelters that lack structural security, water for drinking, cooking, and hygiene, and sanitation. They are exposed to communicable diseases and suffer mental stress. Community space, adequate education, and chances for employment or a way out of the slums are rare. In numerous coastal communities, houses are endangered by extreme weather conditions exasperated by climate change. The sea’s rise in India has caused river delta islands to vanish. In 2016, the first climate refugees in the United States, an entire community of Native American Indians, are being forced to move from their ancestral homes on Isle de Jean Charles, Louisiana. The present challenges are aggravated by climate change, population growth, and forced migration. It is critical to focus on these basic, inextricably interlocked needs for water, food, and secure shelter, with a view to preventive measures, and to do so with extreme sensitivity to cultures, communities, ecosystems, and ramifications to human health.