The elephant in the room is climate change.  NPS Director Jon Jarvis has called climate change “the greatest threat we have to the integrity of our natural resources.” 

We believe that food source disruptions are symptomatic of climate change and that further disruptive ecosystem-wide changes are not only possible, but likely, and will significantly impact grizzly bears.

A warming trend over the past decades is abundantly documented by Yellowstone scientists and is considered a component of the food resource disruptions mentioned previously.

Climate change forecasts generated by Yellowstone National Park's own scientists are ominous and the effects on the ecosystem and the grizzlies are unclear but deemed to be significant regarding the recent collapse of important food resources. 

Other impacts are likely be become apparent in the coming years and decades and these impacts may lead to significant additional displacement of food and habitat resources. Adding to the potential for food security disruption, recent research shows that invasive species out-compete native species in a climate change scenario.