Persistent debate on climate change in the late Nineteenth and early Twentieth century reflected growing concerns with the human impact on the natural environment and became polarized over the issue of the climatological role of forests. This paper examines the debate throughout Australia and New Zealand with a particular focus on how the policy process was influenced by the press, parliament and science. The paper traces the rise and fall of the twin faiths that climate was changing and that human agency was to blame. The role of formal science in ultimately debunking these views provides a remarkable counterpoint to the development of the debate today.