Social impacts of disasters
Natural Disasters can cause social impacts that are similar in different types of communities such as the need for rebuilding, urgent access to health care, simply accessing shelter during/after a storm, availability to food and water, turning towards the government for aid or towards religious organization for aid and moral support.
Increased mental health issues, alcohol misuse, domestic violence, chronic disease and short-term unemployment have resulted from extreme weather events such as bushfires, severe storms, cyclones, floods and earthquakes.
Emergency situations can be an incredibly stressful, disruptive and traumatic time for those affected. Whole communities can be uprooted, friends and family divided, homes, livelihoods and, of course, lives can be lost. In the aftermath of such a disaster, people may experience a range of physical, psychological, emotional or behavioural reactions that, while perfectly natural, can significantly impact their ability to cope with the situation.
People may experience shock and disbelief, fear and apprehension, anger, and shame and guilt in the early days after an event, and over the longer term. Trauma and grief will put personal, family and community relationships under pressure. The mental health impacts of disasters can lead to an increase in problematic alcohol and drug use, self-harm, violence and abuse – which may well act as early warning signs. Whether or not they have experienced direct losses, the disaster may trigger post-traumatic stress for people who have experienced previous trauma, including war service, previous bushfires or house fires, and family loss.
In addition, the ability of a community to recover from a disaster reflects its underlying functioning. Communities that function well in everyday life, with strong social connections and plentiful resources will often be most resilient when facing a crisis. People and communities with pre-existing vulnerabilities or who are disadvantaged are more at risk of the immediate, medium and long-term effects of disasters, such as loss, injury, and social and economic hardship.
Environmental impacts of disasters
Major floods create myriad effects on river-floodplain ecosystems. During periods of low flow, typically in midsummer, the rivers occupy channels. During rainy seasons, rivers spill into their floodplains, recharging the surrounding wetlands, forests, and lakes with fresh supplies of water, nutrients, and sediments. During great floods, floodplains do not merely store water, but become part of the flowing river itself, conveying water slowly downstream through the forests and marshes. Plant and animal species have adapted over time to exploit, tolerate, or escape seasonal floodpulses and exceptional great floods. The combination of the flood-adapted animals and plants, the seasonal flows and great floods, the river and its channels, and the complex patchwork of floodplain habitats constitute the dynamic and phenomenally productive river-floodplain ecosystem.
Large river-floodplain ecosystems provide valuable hydrological and ecological services and functions, such as flood storage and conveyance; the maintenance of biodiversity; retention, recycling, and conversion of potentially polluting nutrients into useful biomass; production of fish, wildlife, and forests; and the provisions of corridors for migratory fish and wildlife. Annual floodpulses help regulate and maintain these ecosystems by promoting exchanges of water, sediment, nutrients, and organisms between the rivers and their floodplains. Moreover, infrequent great floods and droughts help maintain habitat and species diversity.
Unlike floods, droughts generally damage ecological systems and yield few offsetting benefits. In fact, the most subtle and enduring impacts of droughts occur in the environment. The cumulative stress on wetlands, wildlife, forests, ground water, and soils cannot be measured accurately, and many effects occur slowly and over a period of years, making them extremely difficult to quantify.
The problems generated by droughts begin with changes in the quantity and quality of water available in the hydrologic system. Drought damages both plant and animal species by depriving them of food and water, increasing their susceptibility to disease, and increasing their vulnerability to predation. As with floods, droughts produce a loss of biodiversity, and often increase erosion of dried soils when rain eventually comes. Droughts also degrade water quality, shifting salt concentration, pH levels and dissolved oxygen, while increasing water temperatures. Even air quality is diminished because of increased dust and pollutants. Droughts also lead to more wildfires, while adversely changing salinity levels in coastal estuaries and reducing the flushing of pollutants.
Hurricanes and tropical storms create environmental damages within paths that vary from 50 to 150 miles in width. The environmental consequences largely consist of damages to trees and underbrush in the storm path. At the same time, the long-term ecosystem damages of these storms are uncertain. To be sure, during coastal storms in particular there is often significant erosion of shores and beaches. In the long run, however, nature generally has adapted to these events, so the extent of negative impacts of these events is not clear.