Adaptation:Adjustment in natural or human systems in response to actual or expected climatic stimuli or their effects, which moderates harm or exploits beneficial opportunities.
Adaptive capacity:The ability of a system to adjust to climate change (including climate variability and extremes) to moderate potential damages, to take advantage of opportunities, or to cope with consequences.
The extent to which human health is affected depends on: (i) the exposures of populations to climate change and its environmental consequences, (ii) the sensitivity of the population to the exposure, and (iii) the ability of affected systems and populations to adapt (Figure 11.1). We therefore need to understand how decisions are made about adaptation, including the roles of individuals, communities, nations, institutions and private sector.
The main determinants of a community’s adaptive capacity are: economic wealth, technology, information and skills, infrastructure, institutions, and equity. Adaptive capacity is also a function of current population health status and pre-existing disease burdens.
Wealthy nations are better able to adapt because they have the economic resources to invest, and to offset the costs of adaptation. In general, poverty enhances vulnerability – and we live in a world in which approximately one-fifth of the world’s population lives on less than US$1 per day.
Access to technology in key sectors and settings (e.g., agriculture, water resources, health-care, urban design) is an important determinant of adaptive capacity. Many health-protecting adaptive strategies involve technology – some of which is well established, some new and still being disseminated, and some still being developed to enhance coping with a changing climate.
The health risks from proposed technological adaptations should be assessed in advance. For example, increased air conditioning would protect against heat stress, but could increase emissions of greenhouse gases and other air pollutants. Poorly designed coastal "defences" may increase vulnerability to tidal surges if they engender false security and promote low-lying coastal settlements.
Information and skills
In general, countries with more “human capital” or knowledge have greater adaptive capacity (1). Illiteracy increases a population’s vulnerability to many problems (4). Health systems are labor-intensive and require qualified and experienced staff, including those trained in the operation, quality control, and maintenance of public health infrastructure (5).
Infrastructure specifically designed to reduce vulnerability to climate variability (e.g., flood control structures, air conditioning, and building insulation) and general public health infrastructure (e.g., sanitation facilities, wastewater treatment systems, laboratory buildings) enhance adaptive capacity. However, infrastructure (especially if immovable) can be adversely affected by climate, especially extreme events such as floods and hurricanes.
Countries with weak institutional arrangements have less adaptive capacity than countries with wellestablished institutions (1). For example, institutional and managerial deficiencies contribute to Bangladesh’s vulnerability to climate change.
Collaboration between public and private sectors can enhance adaptive capacity. For example, the Medicines for Malaria Venture – a joint public-private initiative to develop new antimalarial drugs – is developing new products for use in developing countries.
Adaptive capacity is likely to be greater when access to resources within a community, nation, or the world is equitably distributed (6). Under-resourced and marginal populations lack adaptive resources. While universal access to quality services is fundamental to public health, many still lack access to health care. Overall, the developing world, with 10 per cent of the world’s health resources, carries 90 per cent of the disease burden (5).
Health Status and Pre-existing Disease Burdens
Population well-being is an important ingredient and determinant of adaptive capacity. Great progress has been achieved in public health, yet 170 million children in poor countries are underweight, of whom over three million die each year. Many countries face the double burden of increases of non-communicable diseases, but with continued prevailing infectious diseases.
Adaptive strategies intended to protect public health will be needed whether or not actions are taken to mitigate climate change. Building capacity is an essential preparatory step. Adapting to climate change will require more than financial resources, technology, and public health infrastructure. Education, awareness-raising and the creation of legal frameworks, institutions and an environment that enables people to take well-informed, long-term, sustainable decisions are all needed.