Informal settlements are found in cities and towns where urban poverty is rife. Residents are often unaware of the vulnerability of their housing - sometimes located directly on river floodplains. Slums lack clean water, energy sources, adequate infrastructure, sanitation, and financial, social, municipal, and/or medical support. Partnered with overcrowding and poor housing conditions, slum populations are already extremely vulnerable to infections and physical, social, and psychological illnesses. Conditions and location characteristics increase the severity of, and sometimes encourage, destruction brought on by changing weather patterns.
Extreme temperatures are a result of climate change and it is estimated that there will be a 2.5°C rise by the end of this century (Prasad, et al. 2009). Heat waves have already become quite prevalent and will continue to increase while frost days will be less frequent, with snow replaced by rain. Characteristic of urban environments is a lack of vegetation and influence by the "heat island" effect, the retaining of heat by urban building exteriors/materials. Slum temperatures are exacerbated by the proximity of city structures, vehicle exhaust emissions, and industrial activity. As heat wave intensity increases, so will heat stroke and mortality from cardio-respiratory diseases. Especially vulnerable are the urban poor, many of whom work in external conditions as laborers (Kovats & Akhtar, 2008). There is a likelihood that heat wave deaths may be compensated for by fewer deaths during warmer winters.
With warmer land mass and cooler oceans, monsoons and cyclones intensify and occur more often. Congested cities, with poor drainage systems, are threatened by flooding and landslides which accompany torrential rains and melting glaciers and snowcaps. When immense spans of ground are covered with manmade forms (as is common in informal settlements), such as roofs and roads, natural rain flow is prevented, leading to runoff and increased river flow (Douglas, et al. 2008). Deforestation and other forms of land-use, such as farming and grazing, on floodplains have led to increased erosion/mudslides. It is evident that human alteration to the landscape has inadvertently encouraged flooding, killing hundreds at a time. Melting glaciers lead to increased sea levels – the Intergovernmental Panel on Climate Change has predicted that sea levels will reach 18 cm by 2040 – flooding coasts, eroding beaches, salinizing of inland rivers and the groundwater table, engulfing cities, and destroying homes (Prasad, et al. 2009). Poor drainage systems and congested canals encourage water contamination by sewage, garbage, and hazardous substances/metals. As the infected water dissipates, the soil becomes contaminated, and eventually the food – slum farming occurs on the same floodplains they live upon.
The majority of slums are positioned in tropical climates, thus are threatened by tropical diseases. Inadequate water systems and low hygiene standards increase vulnerabilities to infection. In the slums of Mumbai, after the floods of 2000, 2001, and 2005, increased cases of leptospirosis were found in children; the infection was attributed to playing or wading through polluted floodwaters that had pervaded streets and homes (Kovats, 2008). The stagnant water following storms is a breeding ground for virus carrying vectors, such as mosquitoes. Studies have shown that the urban poor experience increased rates of infections such as malaria, cholera, cryptosporidiosis, typhoid, diarrhea, and especially dengue fever (pathogens thrive in improper water storage systems) following floods. Increased temperatures also quicken maturation time for some vectors and bite frequency, increasing the incidence of illness and death. Rodent populations also amplify, leading to diseases such as leptospirosis and tularaemia (Campbell-Lendrum & Corvalan, 2003).
The psychological health of urban poor is a major concern. Inadequate living situations, overcrowding, and noise may lead to mental disorders such as depression, anxiety, chronic stress, schizophrenia, and suicide (Confalonieri, et al. 2007). Natural disasters can destroy livelihoods, amplifying mental turmoil amongst the impoverished.
Issues influenced by and influencing climate change are food production and energy use. Malnutrition is an apparent condition within slums, yet climate change only exacerbates food shortages. Agricultural resources can be lost in mudslides, minimizing quantity and quality of food in informal settlements. Methods and aspects of modern food production, such as land-clearing, fertilizers, pesticides, veterinary antibiotics, and methane discharge, aggravate the environment and promote climate shifts. Because energy resources are typically unavailable in the slums, more than 3 billion still rely on burning solid fuels for heating and cooking. Air pollution, intensified by excessive urban automobile use, results and the lack of ventilation increase vulnerability to pneumonia, respiratory infections, and lung cancer (Kjellstrom, et al. 2007).
Anthropogenic greenhouse gases (GHG) are perpetuating the climate change. Yet, the impoverished only contribute about 3% of GHG global emissions. The United States is the largest contributor with 28% of all global emissions (Prasad, et al. 2009). Because the effects of climate change are already significantly impacting society, the necessary step is adaptation. Slums are the most vulnerable and at risk because they are not provided the means to survive disasters, leading to greater asset loss than wealthy sectors (World Development Report, 2009). The only way to proceed is to reduce poverty – raise housing standards, living standards, services, and the status of residents. The World Bank recommends an overhaul of informal settlements by implementing actual land policies (previously lacking which led to haphazard/informal settlement) and allocating "safe sites" to low-income individuals to build structurally reliable "quality housing"(Kovats & Akhtar, 2008). Climate, Housing and Health must always be considered as mutually informing agents of development. New housing or slum upgrading should address thermal, natural disaster, and disease concerns while supporting the environment through energy efficient, low carbon materials, improved drainage, sanitation facilities, and flood control measures. Reducing slum vulnerability is a comprehensive effort that must include public health, social, environmental, and welfare improvements.
Peter Williams is Founder and Executive Director of the ARCHIVE Institute. He is also a visiting scholar in the Healthy Infrastructure Research Centre, University College London.
The author would like to thank Liezel Pimentel at ARCHIVE, for compiling most of the research work on this article.
Image source: International Rice Research Institute