Abstract

Understanding of the anthropogenic influences on the Earth and climate system is built on a foundation where models are the integrating framework for the science. Contemporary climate models, also termed Earth system models, allow us to have insight into how an external forcing on the climate – such as an increase in greenhouse gas emissions from human activity – affects the climate system and the properties of the system that emerge from the complex interactions of the system’s multitude of constituent sub-system and small-scale components. The epistemic challenges present in the science when attempting to understand and predict climate change are largely a consequence of the complicated issues of uncertainty involved in the development and implementation of climate models and their use to create simulations representing possible future climates. This chapter tackles the issue of model-based uncertainty in climate science, focusing on the nature of climate models and the multitude of sources from which uncertainty arises, including structural and parameter uncertainty, scenario uncertainty, and initial condition uncertainty.