Global climate change has stimulated a host of scientific studies and has, in some cases, created a need for disaster mitigation projects to protect local people from catastrophic events. While many people appreciate these efforts, others resent, distrust, or remain ambivalent about them. Sometimes local residents fight against projects that scientists, engineers, and government officials believe will benefit or protect local people. To understand local residents’ views of climate change researchers and disaster prevention programs, this study examines Peru’s Cordillera Blanca mountain range, where twentieth century global warming has produced the world’s most deadly glacial lake outburst floods. These glacier disasters have, in turn, generated both scientific studies of climate change, glacier tongue variation, equilibrium-line altitude, and glacial lake formation, as well as disaster mitigation projects to contain dozens of unstable moraine-dammed glacial lakes. Two broadly-defined social groups inhabit the Cordillera Blanca: (1) rural indigenous people with culturally-specific understanding of hydrological cycles, and (2) urban mestizos (mixed Spanish-indigenous descendants) with Western-science-based knowledge of the environment. This study examines these two groups’ interactions with the Peruvian Glaciology and Lakes Security Office since the 1940s. First, the groups’ perspectives of the Glaciology and Lakes Security Office are analyzed at the time of major glacier disasters (1941, 1950, 1962, 1970, and the 2003 avalanche threat that NASA recently announced), as well as during the initial development of the office (1950s), during its heyday (1970s), and during its recent phase of severe budget and staff cuts (mid-1990s to the present). Second, the study explains how the two local groups’ views and responses were shaped not solely by a scientific understanding (or lack thereof) of natural processes, but rather by: (a) historical circumstances, which produced an inherent distrust of outsiders and government officials; (b) politics, which, according to both local groups, played a bigger role in determining glacier-disaster mitigation projects than did scientific evidence; and (c) spontaneous social responses to disasters, including fear of impending outburst floods and coping with glacier catastrophes. By recognizing that local opinions about scientists and engineers are historically, politically, culturally, and socially produced, researchers can consider local viewpoints and objectives while analyzing effects of global climate change—thereby fostering a more fluid working relationship among scientists, engineers, and local residents.