One is an oddly named and shaped tree inhabiting the high deserts of the Southwest. The other is a river of ice slowly flowing down the Crown of the Continent (among other places). Both are so iconic that national parks were created to highlight their most striking exemplars.
And now both are threatened by climate change.
We'v known about Glacier National Park's shrinking glaciers for some time. Now, research by US Geological Service ecologists suggests that Joshua trees face an uncertain future, limited by a warming climate and restricted to the northernmost portion of its range - excluding Joshua Tree National Park - by the end of this century.
Recently I wandered through the high desert of Joshua Tree National Park. I hiked through a forest, redefined: trees all around me, but no shade from the warm winter sun. The park is commonly described as a remote and forbidding place - a gold mine was active in the late 1800s, but otherwise the land shows few signs of human habitation - although it reveals its beauty to those who have eyes to see.
The Joshua tree, covered with tough spiny leaves and impervious to all but the fiercest fires, seems engineered to survive and thrive in the high desert. Early pioneers, no doubt hallucinating, thought the tree resembled Joshua holding up his arms to stop the sun from setting. However, it's a finicky plant, beginning with the rare germination of a seed, its survival dependent upon well-timed rains. It thrives only in altitudes between 1300 and 5900 feet, ranging from the namesake national park in the south to California's 395 Highway, east of the Sierra Nevada, and St. George, Utah in the north.
Now, a new study predicts an uncertain future for the tree: temperature increases resulting from climate change in the Southwest will likely eliminate Joshua trees from 90 percent of their current range in 60 to 90 years. The tree depends on animals to disperse its seeds. Prior to an abrupt change in climate about 12,000 years ago, the Shasta ground sloth did Johnny Appleseed duties, depositing seeds up to 10 miles away. No modern animal will carry seeds that far. Thus, when the desert warms beyond Joshua trees' tolerance, the trees will die in the park and throughout most of their range.
And in the alphabetical listing of national parks, the Park-Formerly-Known-As-Glacier will be followed by the Park-Formerly-Known-As-Joshua-Tree.