The climate-change controversy

Of all the environmental issues that have emerged in the past few decades, global climate change is the most serious, and the most difficult to manage. It is the most serious because of the severity of harms it might bring. Many aspects of human society and well-being – where we live, how we build, how we move around, how we earn our livings, and what we do for recreation – still depend on a relatively benign and narrow range of climatic conditions, even though this dependence has been reduced and obscured in modern industrial societies by their wealth and technology. This dependence on climate can be seen in the economic harms and human suffering caused by the climate variations of the past century, such as the “El Niño” cycle and the multi-year droughts that occur in western North America every few decades. Climate changes projected this century are much larger than these twentieth-century variations, and their human impacts are likely to be correspondingly greater. Moreover, climate does not just affect people directly: it also affects all other environmental and ecological processes, including many whose connection to climate might not be immediately recognizable. Consequently, large or rapid climate change will represent an added threat to other environmental issues such as air and water quality, endangered ecosystems and biodiversity, and threats to coastal zones, wetlands, and the stratospheric ozone layer.