The Montana setting plays an important role in the novel’s conflict. It is a landscape beloved by the three main characters, but its ecosystem has been harmed by the effects of climate change. Montana encompasses a vast area—the fourth largest American state—with prairie lands in the east and mountain ranges in the west. Historically, it is known for its hot summers and cold winters, with snow prevalent in much of the state during those months. Areas with heavy snowfall are known to average 300 inches per year. Yet the climate is highly impacted by the Continental Divide: The area west of the divide experiences much milder winters, cooler summers, and more regular precipitation. Mountain valleys there have made Montana fertile for growing and harvesting grain (“Climate of Montana.” Western Regional Climate Center).

In the 20th century, Montana’s environment has been significantly impacted by climate change. Since the 1980s, the state’s temperature averages have risen by 2˚ Fahrenheit. This means that dangerous heat waves have become more frequent, and snow melt can occur earlier in the spring. The presence of snow shapes Montana in several ways—not only does its tourism industry depend on it for skiing, but a decrease in snowpack (snow accumulation over the course of a winter) also changes the tree line, causing it to shift. This shift impacts animal habitats, which in turn can endanger certain species. Similarly, the 1,000 glaciers that span northern Montana’s mountains are melting; experts predict that all of the state’s glaciers will be gone by the year 2030. Though rising temperatures can negatively impact agriculture by causing drought, the increased snow melt can offset this, so it is unknown whether Montana’s grain industry will ultimately be harmed or helped. Further, the fate of the state’s forests is also unknown: Increases in carbon dioxide in the environment may be a boon to trees; at the same time, increased temperatures mean increased numbers of insects that can damage forests.

One of the most significant results of temperature increase and drought has been an increase in the number of wildfires in the state each year. Not only do wildfires threaten animal habitat and destroy native forests, but they also pose health risks to humans because of the decreased air quality caused by smoke (“What Climate Change Means for Montana.” United States Environmental Protection Agency, Aug. 2016).

Throughout Dream State, Garrett is involved in tracking wolverines for conservation purposes. Near the end of the novel, his long search for a particular, aging wolverine, whose life he has studied for years, becomes a metaphor for Garrett’s own decline. Garrett notes that wolverines are becoming increasingly scarce in Montana and elsewhere, evidence of Human Impacts on the Environment. The wolverine is the largest member of the family Mustelidae, which includes mammals such as the mink and the weasel. Their weight ranges from 17 to 40 pounds, and they are generally 33 to 44 inches in length and one and a half feet tall. Their preferred habitat is at a high altitude in wooded areas. They are fierce predators of other animals such as rabbits, raccoons, and squirrels, but they will also scavenge from larger animals like deer or elk. It is estimated that the wolverine population in the continental United States is as low as 25 to 300 (“Wolverine.” National Wildlife Federation). The loss of habitat—and potential food sources—due to climate change has caused wolverines to become threatened nationwide.