Almost all advocates of international climate change policy hope and expect that the Climate Change Conference to be held in Paris in November–December 2015 will reach an agreement to reduce global anthropomorphic greenhouse gas emissions. Yet more than 25 years of international climate change policy has failed to reach such an agreement: emissions, far from having been reduced, have greatly increased. In the author’s view, no agreement is likely to be reached in Paris. Anticipating this, Lord Stern, a highly influential figure in international climate change policy, has restated the case for continuing with this policy while relinquishing the objective of reaching such an agreement, argued in 2009 to be essential to ‘save the world’. Advocating the continuation of climate change policy while abandoning an acknowledged condition of its success seems to represent a further stage in the abandonment of rationality in climate change policy formulation.