Elizabeth G. Hanna

Climate Change and Rising Heat: Population Health Implications for Working People in Australia

The rapid rise in extreme heat events in Australia recently is already taking a health toll. Climate change scenarios predict increases in the frequency and intensity of extreme heat events in the future, and population health may be significantly compromised for people who cannot reduce their heat exposure. Exposure to extreme heat presents a health hazard to all who are physically active, particularly outdoor workers and indoor workers with minimal access to cooling systems while working. At air temperatures close to (or beyond) the core body temperature of 37°C, body cooling via sweating is essential, and this mechanism is hampered by high air humidity. Heat exposure among elite athletes and the military has been investigated, whereas the impacts on workers remain largely unexplored, particularly in relation to future climate change. Workers span all age groups and diverse levels of fitness and health status, including people with higher than “normal” sensitivity to heat. In a hotter world, workers are likely to experience more heat stress and find it increasingly difficult to maintain productivity. Modeling of future climate change in Australia shows a substantial increase in the number of very hot days (>35°C) across the country. In this article, the authors characterize the health risks associated with heat exposure on working people and discuss future exposure risks as temperatures rise. Progress toward developing occupational health and safety guidelines for heat in Australia are summarized.

Limitations to thermoregulation and acclimatization challenge human adaptation to global warming

Human thermoregulation and acclimatization are core components of the human coping mechanism for withstanding variations in environmental heat exposure. Amidst growing recognition that curtailing global warming to less than two degrees is becoming increasing improbable, human survival will require increasing reliance on these mechanisms. The projected several fold increase in extreme heat events suggests we need to recalibrate health protection policies and ratchet up adaptation efforts. Climate researchers, epidemiologists, and policy makers engaged in climate change adaptation and health protection are not commonly drawn from heat physiology backgrounds. Injecting a scholarly consideration of physiological limitations to human heat tolerance into the adaptation and policy literature allows for a broader understanding of heat health risks to support effective human adaptation and adaptation planning. This paper details the physiological and external environmental factors that determine human thermoregulation and acclimatization. We present a model to illustrate the interrelationship between elements that modulate the physiological process of thermoregulation. Limitations inherent in these processes, and the constraints imposed by differing exposure levels, and thermal comfort seeking on achieving acclimatization, are then described. Combined, these limitations will restrict the likely contribution that acclimatization can play in future human adaptation to global warming. We postulate that behavioral and technological adaptations will need to become the dominant means for human individual and societal adaptations as global warming progresses.

Preparing health services for climate change in Australia

Although the implications of climate change for public health continue to be elucidated, we still require much work to guide the development of a comprehensive strategy to underpin the adaptation of the health system. Adaptation will be an evolving process as impacts emerge. The authors aim is to focus on the responses of the Australian health system to health risks from climate change, and in particular how best to prepare health services for predicted health risks from heat waves, bushfires, infectious diseases, diminished air quality, and the mental health impacts of climate change. In addition, the authors aim to provide some general principles for health system adaptation to climate change that may be applicable beyond the Australian setting. They present some guiding principles for preparing health systems and also overview some specific preparatory activities in relation to personnel, infrastructure, and coordination. Increases in extreme weather—related events superimposed on health effects arising from a gradually changing climate will place additional burdens on the health system and challenge existing capacity. Key characteristics of a climate change—prepared health system are that it should be flexible, strategically allocated, and robust. Long-term planning will also require close collaboration with the nonhealth sectors as part of a nationwide adaptive response.

Climate change and Australian agriculture: a review of the threats facing rural communities and the health policy landscape.

Population health is a function of social and environmental health determinants. Climate change is predicted to bring significant alterations to ecological systems on which human health and livelihoods depend; the air, water, plant, and animal health. Agricultural systems are intrinsically linked with environmental conditions, which are already under threat in much of southern Australian because of rising heat and protracted drying. The direct impact of increasing heat waves on human physiology and survival has recently been well studied. More diffusely, increasing drought periods may challenge the viability of agriculture in some regions, and hence those communities that depend on primary production. A worst case scenario may herald the collapse of some communities. Human health impacts arising from such transition would be profound. This article summarizes existing rural health challenges and presents the current evidence plus future predictions of climate change impacts on Australian agriculture to argue the need for significant augmentation of public health and existing health policy frameworks. The article concludes by suggesting that adaptation to climate change requires planning for worst case scenario outcomes to avert catastrophic impacts on rural communities. This will involve national policy planning as much as regional-level leadership for rapid development of adaptive strategies in agriculture and other key areas of rural communities.

Climate Change and Human Health: Building Australia’s Adaptation Capacity

The links between climate change and health have been reported by the Intergovernmental Panel on Climate Change, which states that climate change is already contributing to the global burden of disease and premature death and that these effects are likely to increase in all countries. The extent and nature of future health impacts will depend on the nature and magnitude of climate change. Climate change is a global issue, but it will not be experienced uniformly across the globe, and a significant proportion of adaptation measures will need to be developed and implemented at a local or regional level. Understanding the pathway from climate change to predicted health impacts can provide us with critical information for planning effective adaptation strategies. Health impact pathways can occur through a range of direct or indirect exposures. Direct exposures refer to immediate health impacts that occur as a direct result of a climate variable. This type of exposure usually refers to impacts caused by extreme events such as flooding, fires, and heat waves. Indirect exposures occur when climate affects a range of environmental parameters such as air, water, or food quality; food production and disease vectors; or social parameters such as changes to population distribution and economic variables. The pathway between climate and health impact for indirect exposures typically includes multiple steps, many of which occur in nonhealth sectors. Australia adopted a novel approach to build national adaptive capacity to respond to the threats posed by climate change. The Australian government called for tenders for collaborations to host a National Climate Change Adaptation Research Facility (NCCARF), which would generate the knowledge required for Australia to adapt to the physical impacts of climate change and oversee the roll out of Adaptation Research Networks (ARNs) across Australia. A nine member consortium led by Griffith University’s Gold Coast Campus was successful, and NCCARF was established in November 2007 (http://www.nccarf.edu.au/about-facility). Soon afterwards, the Federal Department of Climate Change (now Department of Climate Change and Energy Efficiency) was established in December 2007. NCCARF then repeated the tender process, calling for proposals from nationwide collaborations of researchers to host ARNs across eight key research domains: terrestrial biodiversity; human health; marine biodiversity and resources; water resources and freshwater biodiversity;

Estimating Risks of Heat Strain by Age and Sex: A Population-Level Simulation Model

Individuals living in hot climates face health risks from hyperthermia due to excessive heat. Heat strain is influenced by weather exposure and by individual characteristics such as age, sex, body size, and occupation. To explore the population-level drivers of heat strain, we developed a simulation model that scales up individual risks of heat storage (estimated using Myrup and Morgan’s man model “MANMO”) to a large population. Using Australian weather data, we identify high-risk weather conditions together with individual characteristics that increase the risk of heat stress under these conditions. The model identifies elevated risks in children and the elderly, with females aged 75 and older those most likely to experience heat strain. Risk of heat strain in males does not increase as rapidly with age, but is greatest on hot days with high solar radiation. Although cloudy days are less dangerous for the wider population, older women still have an elevated risk of heat strain on hot cloudy days or when indoors during high temperatures. Simulation models provide a valuable method for exploring population level risks of heat strain, and a tool for evaluating public health and other government policy interventions.

Climate change: an emerging health issue

The World Health Organization chose climate change as the theme for last year’s World Health Day in an explicit attempt to attract policy-makers to the compelling evidence about the impacts of climate change on health. The reality of humaninduced climate change can no longer be doubted, but the extent of its consequences for health can still be reduced. Consideration of the health impacts of climate change can enable political leaders to act with the required urgency.1

Climate change threatens the achievement of the millennium development goal for maternal health.

This article discusses the unlikelihood that the Millennium Development Goal (MDG) 5 improving maternal health will be met by 2015. It describes how climate change has a significant effect on achieving all MDGs particularly MDG 5 and is an essential element of the debate regarding the achievement of the MDGs.

Small Island States - canaries in the coal mine of climate change and health.

This chapter describes the geography, population and demography, economy and health status of small island developing states (SIDS). The drivers of the vulnerability of SIDS to the impacts of climate change (natural disasters, extreme weather events) and some of the key health risks and adaptive options these nations face are discussed. Examples and case studies cited are taken predominantly from Pacific island nations, although their plight is shared more broadly across developing island nations of the Caribbean and Indian Ocean regions.

Determinants of health: the contribution of the natural environment.

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