Climate change awareness, risk perception and policy support vary between and within countries. National-scale comparisons can help to explain this variability and be used to develop targeted interventions.While scientific understanding of the biophysical impacts of climate change has increased, along with degrees of certainty, there is still wide spread variability in public awareness, understanding and risk perceptions within and between countries. The failure of global climate negotiations to achieve a robust international agreement has rested largely on disagreements over targets and financial transfers created in part by the relative ambition of different nations and domestic policy objectives. Public support for national-scale climate policies is predicated on four key beliefs; that climate change is real, human caused, serious and solvable. Certainty that climate change is occurring is strongly associated with support for policy action. Thus raising levels of climate change understanding and risk perception could result in increased acceptance of climate policy and progress international agreements.