Natural Disasters

Natural disasters, also referred to as natural hazards, are extreme, sudden events caused by environmental factors such as storms, floods, droughts, fires and heatwaves. Natural disasters are now occurring with increasing severity, scope and impact. When we explore natural disasters in the context of planetary health, we are utilizing a systems-thinking approach to grasp the complexities and anthropogenic drivers relating a given disaster to causes and effects. 

Globally, twice as many people were affected by natural disasters in the 1990s vs. in the 1980s, and global annual economic losses from extreme events increased 10-fold over the past four decades. Heat waves, droughts, fires, floods, tropical storms, and other natural disasters pose long-term health consequences. For example, particulate matter from fires reduces air quality and causes morbidity and mortality from cardiorespiratory disease; flooding can cause biological contamination of water supplies, displacement and trauma; more intense coastal storms, combined with sea level rise and loss of coastal barrier systems (mangrove forests, vegetated dunes, coral reefs, and wetlands), generate a “triple threat” for inhabitants of low-lying coastal areas. Survivors of natural disasters face serious, yet poorly understood, physical and mental health impacts. It must be a priority to investigate trends in exposure to natural hazards, which populations are most vulnerable, and effective practices for reducing vulnerability.


Risser MD, Wehner MF. Attributable Human-Induced Changes in the Likelihood and Magnitude of the Observed Extreme Precipitation during Hurricane Harvey . Geophysical Research Letters [Internet]. 2017;44 (24). Publisher's VersionAbstract

Record rainfall amounts were recorded during Hurricane Harvey in the Houston, Texas, area, leading to widespread flooding. We analyze observed precipitation from the Global Historical Climatology Network with a covariate-based extreme value statistical analysis, accounting for both the external influence of global warming and the internal influence of El Niño–Southern Oscillation. We find that human-induced climate change likely increased the chances of the observed precipitation accumulations during Hurricane Harvey in the most affected areas of Houston by a factor of at least 3.5. Further, precipitation accumulations in these areas were likely increased by at least 18.8% (best estimate of 37.7%), which is larger than the 6–7% associated with an attributable warming of 1°C in the Gulf of Mexico and Clausius-Clapeyron scaling. In a Granger causality sense, these statements provide lower bounds on the impact of climate change and motivate further attribution studies using dynamical climate models.

Hasan MA, Mouw C, Jutla A, Akanda AS. Quantification of rotavirus diarrheal risk due to hydroclimatic extremes over South Asia: Prospects of satellite-based observations in detecting outbreaks . GeoHealth [Internet]. 2017. Publisher's VersionAbstract

Rotavirus is the most common cause of diarrheal disease among children under five. Especially in South Asia, rotavirus remains the leading cause of mortality in children due to diarrhea. As climatic extremes and safe water availability significantly influence diarrheal disease impacts in human populations, hydroclimatic information can be a potential tool for disease preparedness. In this study, we conducted a multivariate temporal and spatial assessment of thirty-four (34) climate indices calculated from ground and satellite earth observations to examine the role of temperature and rainfall extremes on the seasonality of rotavirus transmission in Bangladesh. We extracted rainfall data from the Global Precipitation Measurement (GPM) and temperature data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors to validate the analyses and explore the potential of a satellite-based seasonal forecasting model. Our analyses found that the number of rainy days and nighttime temperature range from 16°C to 21°C are particularly influential on the winter transmission cycle of rotavirus. The lower number of wet days with suitable cold temperatures for an extended time accelerates the onset and intensity of the outbreaks. Temporal analysis over Dhaka also suggested that water logging during monsoon precipitation influences rotavirus outbreaks during a summer transmission cycle. The proposed model shows lag components, which allowed us to forecast the disease outbreaks one to two-months in advance. The satellite data-driven forecasts also effectively captured the increased vulnerability of dry-cold regions of the country, compared to the wet-warm regions.

Myers SS. Planetary health: protecting human health on a rapidly changing planet . The Lancet [Internet]. 2017. Publisher's VersionAbstract

The impact of human activities on our planet's natural systems has been intensifying rapidly in the past several decades, leading to disruption and transformation of most natural systems. These disruptions in the atmosphere, oceans, and across the terrestrial land surface are not only driving species to extinction, they pose serious threats to human health and wellbeing. Characterising and addressing these threats requires a paradigm shift. In a lecture delivered to the Academy of Medical Sciences on Nov 13, 2017, I describe the scale of human impacts on natural systems and the extensive associated health effects across nearly every dimension of human health. I highlight several overarching themes that emerge from planetary health and suggest advances in the way we train, reward, promote, and fund the generation of health scientists who will be tasked with breaking out of their disciplinary silos to address this urgent constellation of health threats. I propose that protecting the health of future generations requires taking better care of Earth's natural systems.

Sorensen CJ, Borbor-Cordova MJ, Calvello-Hynes E, Diaz A, Lemery J, Stewart-Ibarra AM. Climate Variability, Vulnerability, and Natural Disasters: A Case Study of Zika Virus in Manabi, Ecuador Following the 2016 Earthquake . GeoHealth [Internet]. 2017;1 (8) :298–304. Publisher's VersionAbstract

Climate change presents complex and wide-reaching threats to human health. A variable and changing climate can amplify and unmask ecological and socio-political weaknesses and increase the risk of adverse health outcomes in socially vulnerable regions. When natural disasters occur in such areas, underlying climatic conditions may amplify the public health crisis. We describe an emerging epidemic of Zika virus (ZIKV) in Ecuador following the 2016 earthquake, which coincided with an exceptionally strong El Niño event. We hypothesize that the trigger of a natural disaster during anomalous climate conditions and underlying social vulnerabilities were force multipliers contributing to a dramatic increase in ZIKV cases postearthquake.

Adger WN, W.Arnell N. Successful adaptation to climate change across scales. Global Environmental Change [Internet]. 2005;15 (2). Publisher's VersionAbstract

Climate change impacts and responses are presently observed in physical and ecological systems. Adaptation to these impacts is increasingly being observed in both physical and ecological systems as well as in human adjustments to resource availability and risk at different spatial and societal scales. We review the nature of adaptation and the implications of different spatial scales for these processes. We outline a set of normative evaluative criteria for judging the success of adaptations at different scales. We argue that elements of effectiveness, efficiency, equity and legitimacy are important in judging success in terms of the sustainability of development pathways into an uncertain future. We further argue that each of these elements of decision-making is implicit within presently formulated scenarios of socio-economic futures of both emission trajectories and adaptation, though with different weighting. The process by which adaptations are to be judged at different scales will involve new and challenging institutional processes.

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