Public health ethics in times of global environmental change: time to look beyond human interests

Abstract

In public health, awareness of the threats to human health of global environmental change is slowly increasing. Important examples of global environmental change are climate change, large-scale soil degradation, freshwater depletion, and biodiversity losses [1]. These are all due to increased human pressure on our planetary environment, driven by population growth and an increase in per capita resource use and waste production. Global environmental changes form potential, though partly or largely unknown, threats to human health, for example through heatwaves and other extreme weather events, changes in the spread of microorganisms, changes in biological productivity of land and water, and air and water pollution [2]. While these potential threats to human health are important enough to warrant the attention of public health researchers and policy-makers [3], the impact of global environmental change on the health of other species is actually much larger. The rise in human population numbers, from slightly below 1 billion in 1800 to more than 6 billion in 2005, has been associated with a massive extinction of other living species. This is due to habitat destruction, introduction of invasive non-native species, pollution of air, water, and soil, and over-harvesting by hunting and fishing [4]. The total number of living species has been estimated to be around 6 million. As a result of gradually changing environments, species come and go, albeit on a rather large time-scale (0.1 to 10 million years). On the basis of fossil records, it has been possible to estimate the long-term background extinction rate, i.e. the rate at which species have disappeared in the past. This is around one to five species per year, taking all forms of life together [4]. Currently, the extinction rate of mammals and birds alone is approximately one species per year. If the extinction rate of these well-researched species is indicative of that of invertebrates, the total number of species disappearing each year could be in the order of 1,000. If current trends of habitat destruction continue, half of all living species may disappear in the coming 50 to 100 years [4]. In the words of one biologist, during these years life on earth will go through a narrow bottleneck, and this will require determined conservation measures [5].