Browse

You are looking at 91 - 100 of 542 items for :

  • Weather, Climate, and Society x
  • All content x
Clear All
Nuria Vargas and Víctor Magaña

Abstract

During the second half of the twentieth century, rapid demographic growth and urban expansion led to the development of the Mexico City metropolitan area (MCMA) urban heat island (UHI). The thermal gradient between rural and urban regions is used to define the UHI in the transition zone along the 26°C isotherm of mean maximum temperature. As the MCMA expands, more natural vegetation is replaced with urbanization, and the spatial extent of the 26°C isotherm grows. The loss of natural vegetation, in a densely populated region of Mexico, leads to the formation of a canopy-layer UHI. The intensification of the MCMA UHI results in an increase in the frequency of daily maximum temperatures above 30°C (above 26°C on a weekly average), a threshold value that constitutes a natural hazard. Warm-spell occurrences are related to an increase in the number of acute diarrhea diseases (ADD), mainly in zones of the MCMA where the socioeconomic and environmental conditions are low (e.g., insufficient access to potable water). Vulnerable people are mostly located in new settlements along the periphery of the MCMA, where large numbers of hospital discharges due to ADD are reported. The combined effect of more frequent warm spells and increasing vulnerability results in higher levels of risk of suffering this type of health problem, mainly during the warmest part of the year. This analysis may serve to develop UHI mitigation strategies and early warning systems to manage high levels of ADD risk during warm spells.

Free access
Gabrielle Roesch-McNally, Michael Chang, Meghan Dalton, Scott Lowe, Charlie Luce, Christine May, Gary Morishima, Philip Mote, Alexander “Sascha” Petersen, and Emily York

Abstract

The Fourth National Climate Assessment (NCA4) provided the most up-to-date understanding of climate change and its effects on the Earth system and on consequences for the United States, including impacts and associated risks, along with approaches to coping with these effects. It is intended to provide guidance to decision-makers in governmental sectors while, in practice, providing guidance for nongovernmental actors. Its regional and topical chapters highlight current knowledge, uncertainties, gaps in knowledge, and emerging threats. The current knowledge and gaps can help set a research agenda to inform future national, regional, and local climate assessments and thereby support better decision-making. The evolution of the assessment, including greater diversity in participation, and more grounded research in the Northwest represents a growing and deepening engagement with more diverse participants. This shift emphasizes the importance of diversity, inclusion, and a greater acknowledgment of multiple ways of knowing, including local and Indigenous knowledge. The Northwest chapter reflects the broader shift in framing from NCA3 to NCA4 to better understand how climate impacts pose risks to things of value in each sector or region. It considers climate impacts through five broad ways in which humans relate to the environment: natural resource economy; heritage and quality of life; water, transportation, and infrastructure; health and social systems; and frontline communities. We reflect on the assessment process and identify three recommendations to improve the assessment outcomes and processes: seek new ways to 1) engage diverse authors and stakeholders and 2) value and integrate epistemic plurality and different knowledge systems, and 3) when gaps are identified, promote research or data collection efforts designed to fill those gaps. Done well, the assessment can build support and knowledge to facilitate community action, leading to broader resilience.

Free access
David R. Perkins IV, Kristin Timm, Teresa Myers, and Edward Maibach

Abstract

Broadcast meteorologists—highly skilled professionals who work at the intersection between climate scientists and the public—have considerable opportunity to educate their viewers about the local impacts of global climate change. Prior research has shown that, within the broadcast meteorology community, views of climate change have evolved rapidly over the past decade. Here, using data from three census surveys of U.S. broadcast meteorologists conducted annually between 2015 and 2017, is a comprehensive analysis of broadcast meteorologists’ views about climate change. Specifically, this research describes weathercasters’ beliefs about climate change and certainty in those beliefs, perceived causes of climate change, perceived scientific consensus and interest in learning more about climate change, belief that climate change is occurring (and the certainty of that belief), belief that climate change is human caused, perceptions of any local impacts of climate change, and perceptions of the solvability of climate change. Today’s weathercaster community appears to be sharing the same viewpoints and outlooks as most climate scientists—in particular, that climate change is already affecting the United States and that present-day trends are largely a result of human activity.

Open access
António Lobo, Sara Ferreira, Isabel Iglesias, and António Couto

Abstract

Walking safety has been a primary concern for researchers and authorities, who have developed numerous studies concerning the interaction between pedestrians and vehicles. Nevertheless, few studies have focused on the impacts of weather conditions on pedestrian–vehicle collisions. This research aims at improving knowledge on this subject by investigating the impact of daily precipitation and the lagged effects associated with past accumulated precipitation. Using the city of Porto, Portugal, as a case study, an incremental approach consisting of three models, one Poisson and two negative binomial, was developed to explore the relation between weather conditions and the occurrence of pedestrian–vehicle collisions. The first model accounts exclusively for meteorological variables, providing an insight into the trends of crash frequency under the effects of temperature and precipitation. Then, variables for road classification and land use were introduced in the second and third models, respectively, to account for the diversity of the urban environment. These variables act as proxies for the level of exposure associated with different types of urban space, allowing for a more in-depth understanding of the impacts caused by meteorological conditions. The modeling results show that the number of pedestrian–vehicle collisions tends to increase on rainy days, following the general trend observed in the literature for other types of crashes. Regarding the lagged effects, the results show that the number of pedestrian–vehicle collisions is likely to decrease after a wet week but increases after a wet month.

Free access
Raoni Demnitz and Susan Joslyn

Abstract

The four experiments reported here tested the impact of recent negative events on decision-making. Participants were given a virtual budget to spend on crops of varying costs and payoffs that, in some cases, depended on drought conditions. Participants made 46 decisions based on either deterministic or probabilistic seasonal climate predictions. Participants experienced a sequence of droughts either immediately prior to the target trials (recent condition) or early in the sequence (distant condition). In experiment 1, participants made overly cautious crop choices when droughts were experienced recently. Subsequent experiments probed the cognitive mechanisms involved. The effect of recency on overcautiousness was reduced by a midexperiment message, although it did not matter whether the message described a changed or consistent venue and time period. This suggests that overcautiousness was not caused by deducing a climatic trend in the particular area. Instead, we argue that availability—events that are easier to recall are judged to be more likely—was the major cause for increased cautiousness following recent droughts. Importantly, probabilistic predictions attenuated the impact of recency, inspired greater trust, and allowed participants to make better decisions overall than did deterministic predictions. Implications are discussed.

Free access
Erika O. Pham, Christopher T. Emrich, Zhenlong Li, Jamie Mitchem, and Susan L. Cutter

Abstract

This study investigates evacuation behaviors associated with Hurricane Matthew in October of 2016. It assesses factors influencing evacuation decisions and evacuation departure times for Florida, Georgia, and South Carolina from an online survey of respondents. Approximately 62% of the Florida sample, 77% of the Georgia sample, and 67% of the South Carolina sample evacuated. Logistic regression analysis of the departures in the overall time period identified variability in evacuation timing, primarily dependent on prior experience, receipt of an evacuation order, and talking with others about the evacuation order. However, using four logistic regressions to analyze differences in departure times by day shows that the only significant variable across the three main days of evacuation was our proxy variable for evacuation-order times. Depending on the day, other variables of interest include number of household vehicles, previous hurricane experience, and receipt of an evacuation order. Descriptive results show that many variables are considered in the decision to evacuate, but results from subsequent analyses, and respondents’ comments about their experiences, highlight that evacuation orders are the primary triggering variable for when residents left.

Free access
Meena Sehgal and Sujit Ghosh

Abstract

Malaria and dengue fever are among the most important vectorborne diseases in the tropics and subtropics. Average weekly meteorological parameters—specifically, minimum temperature, maximum temperature, humidity, and rainfall—were collected using data from 100 automated weather stations from the Indian Space Research Organization. We obtained district-level weekly reported malaria cases from the Integrated Disease Surveillance Program (IDSP), Department of Health and Family Welfare, Andhra Pradesh, India, for three years, 2014–16. We used a generalized linear model with Poisson distribution and default logarithm-link to estimate model parameters, and we used a quasi-Poisson method with a generalized additive model that uses nonparametric regression with smoothing splines. It appears that higher minimum temperatures (e.g., >24°C) tend to lead to higher malaria counts but lower values do not seem to have an impact on the malaria counts. On the other hand, higher values of maximum temperature (e.g., >32°C) seem to negatively affect the malaria counts. The relationships with rainfall and humidity appear to be not as strong once we account for smooth (weekly) trends and temperatures; both smooth curves seem to hover around zero across all of their values. We note that a rainfall amount between 40 and 50 mm seems to have a positive impact on malaria counts. Our analyses show that the incremental increase in meteorological parameters does not lead to an increase in reported malaria cases in the same manner for all of the districts within the same state. This suggests that other factors such as vegetation, elevation, and water index in the environment also influence disease occurrence.

Free access
Brooke Fisher Liu, Anita Atwell Seate, Irina Iles, and Emina Herovic

Abstract

Since the 1970s, the National Weather Service has trained citizens to collect, confirm, verify, or supplement radar and other data to contribute to a weather-ready nation. This study examines citizens who volunteer as weather spotters through a case study of an award-winning network. We uncover what motivates citizens to become involved in government science projects. Through the lens of relationship management theory and the related network approach, the study provides some of the first evidence on the benefits and drawbacks of citizens serving as amateur scientists and risk communicators and how these citizen scientists sustain their relationships with government scientists.

Free access
Barbara Millet, Andrew P. Carter, Kenneth Broad, Alberto Cairo, Scotney D. Evans, and Sharanya J. Majumdar

Abstract

Increasingly, the risk assessment community has recognized the social and cultural aspects of vulnerability to hurricanes and other hazards that impact planning and public communication. How individuals and communities understand and react to natural hazard risk communications can be driven by a number of different cognitive, cultural, economic, and political factors. The social sciences have seen an increased focus over the last decade on studying hurricane understanding and responses from a social, cognitive, or decision science perspective, which, broadly defined, includes a number of disparate fields. This paper is a cross-disciplinary and critical review of those efforts as they are relevant to hurricane risk communication development. We focus on two areas that, on the basis of a comprehensive literature review and discussions with experts in the field, have received comparatively little attention from the hazards community: 1) research concerning visual communications and the way in which individuals process, understand, and make decisions regarding them and 2) the way in which vulnerable communities understand and interact with hurricane warning communications. We go on to suggest areas that merit increased research and draw lessons or guidance from the broader hazards/social science research realm that has implications for hurricane planning and risk communication, particularly the development and dissemination of hurricane forecast products.

Free access
Michael Robert Nkuba, Raban Chanda, Gagoitseope Mmopelwa, Margaret Najjingo Mangheni, David Lesolle, and Edward Kato

Abstract

This study investigated the abiotic and biotic environmental indicators used among pastoralists and arable farmers to predict the onset and cessation of rain as well as to make short-term and seasonal forecasts in the Rwenzori region of Western Uganda. We used a mixed-methods approach that included surveys of 907 households, focus group discussions, and key informant interviews. The results indicate that resident birds such as white-browed coucals and turacos and migrant birds such as eagles and swallows were important indicators of the onset of rains. Butterflies were an important indicator for the cessation of rains, and red ants were an indicator for the onset of rains. Among the abiotic indicators, winds, clouds, earthquakes, and cloud formation on Mount Rwenzori were important indicators. Behavior of cattle at the onset of rains was important among the pastoralists, and flowering of coffee plants was important among the arable farmers. The behavior of the biotic indicators was driven by the availability of food, water, or other necessities. An attempt to explain the phenology underlying the behavior of biotic indicators and the meteorological science underlying some of the abiotic indicators is made. Although biotic environmental indicators are rudimentary and their accuracy is influenced by external factors such as climate change, they provide climate information within the locality of the farmers. Our results suggest that the indicators used in indigenous forecasting could be incorporated in national meteorological systems in a bid to improve the accuracy of rainfall forecasts and their use among farmers and pastoralists in rural Africa.

Free access