Although integrated assessment models (IAM) of the Intergovernmental Panel on Climate Change (IPCC) consider
population, along with economic growth and technological change, as one of the root causes of greenhouse gas emissions, how population dynamics affect climate change is still under debate. While policy debates around climate change engender lively discussion on a number of factors, population is rarely mentioned. Studies in the past decade have added significantly to understanding the mechanisms and complexity of population and climate interactions. In addition to the growth of total population size, research shows that changes in population composition (i.e. age, urban-rural residence, and household structure) generate substantial effects on the climate system. Moreover, studies by the impact, vulnerability and adaptation (IAV) community also reveal that population dynamics are critical in the near term for building climate change resilience and within adaptation strategies. This paper explores how global population dynamics affect carbon emissions and climate systems, how recent demographic trends matter to worldwide efforts to adapt to climate change, and how population policies could make differences for climate change mitigation and adaptation.