Geoscience Reference
In-Depth Information
and oceanic changes. h ese factors act simultaneously and involve feedback
loops, producing changes in regional and global climate. For regions like the
American West, the net result over the past 20,000 years has been a climate
that l uctuates broadly between warmer and colder, wetter and drier, and
is punctuated by more extreme l oods and droughts that recur on a regular
basis.
h e average climate in the West has been relatively benign over the past
century and a half, encouraging human settlement and expansion. A certain
faith in the reliability of water needed for the quality of life we enjoy has
also fostered a tremendous population growth. In the following chapter, we
present an overview of how humans during the past 150 years have adapted to
the climate in the West and the ways in which these adaptations, including
extensive water development projects, have af ected ecosystems in the West,
particularly those in the aquatic environment.
