Geoscience Reference
In-Depth Information
f igu r e 34 . Lake Powell, in 2009, showing a white calcium carbonate “bathtub ring”
exposed at er a decade of drought lowered the level of the reservoir to 60 percent of its
capacity. (Photo courtesy of U.S. Bureau of Reclamation.)
West were to melt by May, there would not be any water supply during the
mid- to late summer, severely af ecting the animals and plants that depend
on that water.
In an ef ort to predict the possible ecological consequences of these
changes, Harte's research team has been conducting empirical experiments
artii cially heating wildl owers in a Colorado meadow near Crested Butte
since the early 1990s. h is research documents the fact that wildl owers
bloom earlier when temperatures rise, and it indicates the consequences of
that trend. In many cases, wildl owers depend on, and sustain, migrating
butterl ies that pollinate them. But the pollinators are not arriving earlier:
their migration is triggered by day length, not temperature. h is has dire
consequences for the wildl owers (not to mention for the butterl ies as well),
threatening an enormous decline in their abundance.
Dozens of plant and animal species are now threatened by climate-
induced changes in their food and water sources, habitats, and natural
temperature ranges. In prehistoric periods of climatic warming, plants and
animals had the time and space to gradually shit their habitats to higher
