Health Risks and Costs of Climate Variability and Change

Abstract

The scientific community agrees that climate change is happening, is largely human induced, and will have serious consequences for human health (Field and others 2014). The health consequences of climate variability and change are diverse, potentially affecting the burden of a wide range of health outcomes. Changing weather patterns can affect the magnitude and pattern of morbidity and mortality from extreme weather and climate events, and from changing concentrations of ozone, particulate matter, and aeroallergens (Smith and others 2014). Changing weather patterns and climatic shifts may also create environmental conditions that facilitate alterations in the geographic range, seasonality, and incidence of some infectious diseases in some regions, such as the spread of malaria into highland areas in parts of Sub-Saharan Africa. Changes in water availability and agricultural productivity could affect undernutrition, particularly in some parts of Africa and Asia (Lloyd, Kovats, and Chalabi 2011). Although climate change will likely increase positive health outcomes in some regions, the overall balance will be detrimental for health and well-being, especially in low- and lower-middle-income countries that experience higher burdens of climate-sensitive health outcomes (Smith and others 2014).The pathways between climate change and health outcomes are often complex and indirect, making attribution challenging. Climate change may not be the most important driver of climate-sensitive health outcomes over the next few decades but could be significant past the middle of this century. Climate change is a stress multiplier, putting pressure on vulnerable systems, populations, and regions. For example, temperature is associated with the incidence of some food- and water-borne diseases that are significant sources of childhood mortality (Smith and others 2014). Reducing the burden of these diseases requires improved access to safe water and improved sanitation. Poverty is a primary driver underlying the health risks of climate change (Smith and others 2014). Poverty alleviation programs could improve the capacity of health systems to manage risks and reduce the overall costs of a changing climate.Climate change entails other unique challenges:Significant reductions in greenhouse gas emissions (mitigation) in the next few years will be critical to preventing more severe climate change later in the century, but they will have limited effects on weather patterns in the short term. In terms of costing, another complexity is that these policies and technologies are associated with short-term health benefits (Garcia-Menendez and others 2015).Reducing and managing health risks over the next few decades will require modifying health systems to prepare for, cope with, and recover from the health consequences of climate variability and change; these changes are part of what is termed adaptation. Adaptation will be required across the century, with the extent of mitigation being a key determinant of health systems’ ability to manage risks projected later in the century (Smith and others 2014). No matter the success of adaptation and mitigation, residual risks from climate change will burden health systems, particularly in low- and middle-income countries (LMICs).Given these complexities, estimating the costs of managing the health risks of climate variability and change is not straightforward. The wide range of health outcomes potentially affected means counting (1) costs associated with increased health care and public health interventions for morbidity and mortality from a long list of climate-sensitive health outcomes; (2) costs associated with lost work days and lower productivity; and (3) costs associated with well-being. Costs could also accrue from repeated episodes of malaria, diarrhea, or other infectious diseases that affect childhood development and health in later life. Costs associated with actions taken in other sectors are also important for health, such as access to safe water and improved sanitation. A portion of the costs of managing the health risks associated with migrants and environmental refugees could be, but has not been, counted.Further, costs and benefits will be displaced over time, with costs associated with increased health burdens occurring now because of past greenhouse gas emissions and benefits occurring later in the century because of mitigation implemented in the next few years. A few preliminary estimates have been made of the costs of adaptation. However, more work is needed to understand how climate variability and change could affect the ability of health systems to manage risks over long temporal scales.This chapter reviews the health risks of climate variability and change, discusses key components of those risks, summarizes the attributes of climate-resilient health systems, provides an overview of the costs of increasing health resilience that arise from other sectors, reviews temporal and spatial scale issues, and summarizes key conclusions regarding the costs of the health risks of climate change.