This thesis is an integrated study that links several disciplines-archaeology, anthropology, geography, atmospheric sciences, and microbiology. It attempts to generate an argument that central to climate change is disequilibrium in human ecologies- in my case, disease ecologies in Iceland during the 15th century. This thesis investigates the environment's effect on human adaptability. The effect of the environment on Icelanders as they moved from settlement to later periods was disquieting. The climate of the world was changing- moving from the Medieval Warm Period to the colder Little Ice Age. I analyze the disease ecology of the 15th century and also conduct an archeological and cultural analysis of the Icelandic people, to show the deficiencies in their adaptation, and submit that certain shortcomings in their physical environment, as well as the inadequate adaptive synthesis to the environment, led to a marginal adaptation. This was augmented by political unrest and problems with outside trade, which left them vulnerable and susceptible to disease pathogenesis. I discuss the climate change during the Little Ice Age, and assert that this event is the crucible that crushed Iceland after 400 years of reasonably good fortune. Hundreds of epidemics, natural disasters, and hardships befall the Icelanders. One of them is the plague, which comes twice in the 15th century. The important observation here is that the epidemiological and archeological evidence does not always match up. The principal problem is that the traditional vector for the disease cannot have survived the climate as it was in the winters during the LIA. I offer an analysis that pontificates this issue and I examine the ongoing debate concerning The Black Death in Europe. I introduce another possible explanation: the introduction of disease through environmental vectors. The creation of disease ecologies through climate change is important, in light of problems that we face today. I discuss the phenomenon of the dust storm and its connection to disease pathogenesis. By showing several key examples of dust from Africa to disease pathogenesis in the Caribbean, I make the connection a good one. In addition to this connection is the atmospheric analysis that shows incontrovertibly that the dust found in Greenland ice cores is only from Asia. Finally, there is the fact that the inveterate loci of the plague bacterium is located in the same areas that Asian Dust Events occur and travel from. I create a methodology for investigating this disease ecology and am able to show that the pathogen can be identified in situ- meaning that it can be found in geological deposits that can be properly dated. My pilot study creates a methodology for the examination of ice cores- the principal reservoir for atmospheric deposits made during the LIA. Finally, I look at the aftermath. I introduce the idea of disease ecology, as opposed to that of a healthy ecology, and suggest by the end of the thesis that within the disease ecology are created many of the platforms for emergent biological changes that translate through evolution over time. Like the bacterium in the ice core, I suggest that evidence for disease states in the history of a people can be found through laboratory techniques. The presence of the CCR5 gene mutation is indicative of such a presence. I believe that the presence of the delta 32 gene mutation found in Icelandic people is the result of being exposed to the plague in the 15th century. This thesis is a platform for future synoptic scale disease studies. / Graduation date: 2005