Simon Hales Wellington School of Medicine, Wellington, New Zealand Impacts of global climate change on human health

Readings Many high quality reports and journal articles are available online Some resources for researchers are also available, including climate data and scenarios

What is climate change? What are the relevant health issues? What factors affect vulnerability? What options are available for adaptation? Overview

Global climate change  Destabilization of the Earth’s climate due to altered composition of the atmosphere (increased concentrations of “greenhouse” gases such as CO 2 )  Greenhouse gases trap solar radiation leading to global warming

Likely effects of climate change  a rise in sea level of about 50cm by 2100  A progressive increase in temperatures; an increased occurrence of very hot days, and a decrease in very cold days  an intensification of the global hydrological cycle, with altered global patterns of floods and droughts

Main types of potential health impact of global climate change direct effects (relatively easy to assess) indirect effects (more difficult to assess, but expected to predominate)

Direct effects sea-level rise, with population displacement and damage to infrastructure altered frequency of extreme events (deaths, injuries, psychological disorders) exposure to thermal extremes (altered rates of heat and cold-related illness and death)

Indirect effects altered local ecology of water-borne and food-borne infective agents altered food production due to changes in climate, weather events, and associated diseases effects on the range and activity of vectors and infective parasites

social, economic and demographic dislocations due to adverse climate change impacts on economy, infrastructure, and resources

IPCC’s conclusion “climate change is likely to have wide-ranging and mostly adverse impacts on human health, with significant loss of life” (IPCC, 1996)

Some complexities... Interdependence of climate change with other global issues Complex mechanisms and feedbacks at local, regional and global scales

Some key implications Human health is an “integrating” outcome of climate impacts Impacts will be strongly dependent on non- climate factors (upon local and regional context or “vulnerability”) Impacts might be greatly lessened by effective adaptations which reduce vulnerability

Determinants of vulnerability Poverty and inequality Resources: technical, economic, community, natural resources Population trends: growth, urbanisation, migration

“Cross-sectoral” measures Public policies to reduce vulnerability, including promotion of social equity within and between countries; rescheduling or cancellation of foreign debt; alteration of trade rules

“Public health” measures Improved surveillance of disease incidence and vector populations; vector control measures; epidemic warnings; possibly quarantine measures; improved public health infrastructure

“Inter-sectoral” adaptation measures (outside the health sector): early warning systems; planning of human settlements; disaster preparedness programmes; civil engineering planning; safe water supplies; waste management; sanitation

Summary Many “no regrets” measures are possible These would address current health problems in the short term In the long term, successful adaptation to climate change requires ecologically sustainable development