Geoscience Reference
In-Depth Information
thirteen
Future Climate Change and the
American West
Many scales of climate change are in fact natural, from the slow
tectonic scale, to the fast changes embedded within glacial and
interglacial times, to the even more dramatic changes that char-
acterize a switch from glacial to interglacial. So why worry about
global warming, which is just one more scale of climate change?
h e problem is that global warming is essentially of the scale
of normal in two ways: the rate at which this climate change is
taking place, and how dif erent the “new” climate is compared
to what came before.
Anthony Barnosky,
Heatstroke
lilacs and snowmelt: warning signs
A sure sign of the beginning of spring in the American West is the
annual bloom of wildl owers: they blanket hillsides and i elds, setting them
ablaze with color. During the 1990s, Dan Cayan, Susan Kammerdiener, Mike
Dettinger, and Dave Peterson, all climate researchers at the U.S. Geological
Sur vey, took an interest in the fragrant lilac. h ey were looking for plant data
that would provide a key to interpreting satellite imagery of the mountain
snowpack, a critically important feature of the water supply in the West. h ey
did not start out wanting to know more about l owers; rather, they wanted to
know more about snow cover. As it happens, the two are intimately linked.
h e idea began in 1957, when Montana's state climatologist Joe Caprio
distributed lilac plants (
Syringa vulgaris
) to people across the West, request-
ing that they send him annual postcard reports with the dates of when the
l owers sprouted and bloomed. Lilacs were chosen because they are found
throughout the United States, they thrive in all types of soil and climate con-
ditions, and they bloom in response to the increase in spring temperatures.
Four decades later, when Cayan and his fellow climatologists inherited
these accumulated data on western spring wildl owers, they found surprising
