The importance of uncertainty to climate change

Climate change policy must be discussed in terms of the uncertainty of future outcomes. Climate policy discussion now hinges on long-term scientific or economic forecasts which are, by their nature, imprecise. The reality is that is that it is difficult to precisely predict changes in climate, economies, and geopolitics over the time-scales involved (e.g. 50-100 years). Complex statistical models can give some idea of the range of possible outcomes, but the likelihood of specific outcomes is hazy. There is a small, but unknown risk of catastrophic consequences. It is the uncertainty in the chance of catastrophe that is particularly concerning to scientists. Discussion of climate change needs to include acknowledgement of this uncertainty. Climate change policy should be dictated by the risk aversion of the public, or how much risk is acceptable for the costs of reducing it.

The importance of risk aversion is noted in this MIT debate on the release of emails, code, etc from the Climate Research Unit at the University of East Anglia. The debate is the most interesting commentary I have seen of that event, as it contains varied viewpoints on the implications for science and climate change policy. It is noted in the debate that individuals’ opinions on climate change policy are already largely informed by their aversion to environmental risk. This implies that the acceptability of different levels of environmental risk to the general public should be a central component of how nations approach the challenges of climate change. This requires discussing openly the unknown factors in predictions of the future, and not relying on ‘most likely’ outcomes.

This is not to deride predictive models as worthless. They are vital to give an indication of where the world is headed. However the extremities of probability are notoriously hard to predict, and may not be predictable within a time-frame that the prediction is useful. Neither does this mean that discussion of climate change policy should simply be spun to emphasise extreme events and catastrophic destruction. A better approach may be to accept that science tells us the general direction the world is headed, but there is great uncertainty as to where specifically within a spectrum of possibilities. The fact that science is uncertain of the exact outcome may in fact make the general public more inclined to mitigating climate change. Firstly, it is honest. Addressing the uncertainties involved in the scientific predictions may be more convincing compared to the typical approach of more radical environmentalists – hysterical alarmism. Secondly, aversion to small risks with significant consequences has often been a powerful driver for human action. It is risk aversion that makes insurance companies successful, and encourages people to follow safety regulations.