With so many other social, economic and environmental factors at work establishing linear, causative relationships between anthropogenic climate change and population dynamics it has been difficult to pinpoint the specific human consequences of climate change on respective populations. Qualitative information was examined based on interviewees’ testimonies and personal experience, as well as a descriptive analysis of population records, climate-change related impacts, and consequences of uneven development in the Republic of Kiribati and Tuvalu, two low-lying atoll nations in the Pacific region taken as examples to illustrate the issues involved. Strong evidence was found that recent influxes in population movements to urban central islands from rural outer islands experienced in these countries can be attributed to a combination of the adverse impacts of climate change and socioeconomic factors inherit in small island developing states. Moreover, internal migrants cannot be accommodated in their states of origin, putting pressure on local infrastructure and services. This, combined with a recent population boom, has led to a decline in human development indicators and a general livelihood decline.