Uncertainty in global environmental and resource problems

Abstract

Our plans for climate change mitigation and adaptation depend largely on what the climate will be like in the future and what resources will be available. We therefore need to get some sort of handle on the future. This is easiest in a precise science such as planetary astronomy. We can, for example, predict very accurately when eclipses will occur, or when Halley's comet will return, as we have accurate mathematical models to predict these, based on well-validated physical laws. This comfortable certainty disappears in cases where humans can influence the future, as is the case for anthropogenic emissions of greenhouse gases, or land-use changes. Further, there is even uncertainty about the scientific aspects of climate change, particularly the climate sensitivity. This chapter explores the uncertainty that surrounds the likely future of both our global environment, particularly climate, and resource availability. We examine the various techniques that have been used to handle uncertainty, including detailed analysis of historical trends, expert solicitation, scenario analysis, and the Precautionary Principle. Given the uncertain response of the climate system to given levels of greenhouse gases, and the difficulty of reversing the melting of the Greenland ice cap, for example, we suggest that the Precautionary Principle should guide prudent policy. In general, the optimisation approaches of engineering will need to be replaced by ones which include more recognition of both rising uncertainty and ethical considerations.