Caspar Ammann, a climate scientist working at the National Center for Atmospheric Research, also spoke at the symposium, providing graph after graph of colored lines that pointed to bad news. "What-if" scenarios, he said, show even if the world stabilizes greenhouse emissions right now, the world would still warm up a fraction of a degree. If we keep on with "business almost as usual," temperatures will rise 8 degrees Fahrenheit by the end of the 21st century, he said.

The result, he says, will be "of a magnitude we haven't seen before." He reiterated the conclusion drawn earlier this year in Paris by the Intergovernmental Panel on Climate Change that it is "very unlikely" that global climate change of the past 50 years can be explained by natural causes alone.

Rising temperatures can mean "the potential for re-assortment of species," said USU's Wagner, who acknowledged that all this is "incredibly complex and is nothing that can be predicted at this point in time." But already, he said, scientists are observing that the phenology of plants and animals — when they bloom, reproduce, migrate — is changing. Robins in the Rocky Mountains, for example, are now migrating back 10 to 15 days earlier in the spring than they did 30 years ago.

Some species, like a variety of checkerspot butterfly, have been moving north. The red fox has moved farther north into Canada, putting it in conflict with the Arctic fox. The mountain pine beetle has moved north into British Columbia, decimating lodgepole pines there. Scientists are concerned that when the pine beetle moves into other new areas it will jump to other types of pines.

Rising air temperatures also increase the temperature of bodies of water, from oceans to streams. In Utah, that means that cutthroat trout, which prefer low-temperature waters, will move upstream, until they might eventually run out of water cold enough to live in, he said.

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