PREPARING FOR CLIMATIC CHANGE: THE WATER, SALMON, AND
FORESTS OF THE PACIFIC NORTHWEST
PHILIP W. MOTE
, ALAN F. HAMLET
WILLIAM S. KEETON
, DENNIS LETTENMAIER
, NATHAN MANTUA
EDWARD L. MILES
, DAVID W. PETERSON
, DAVID L. PETERSON
and AMY K. SNOVER
JISAO/SMA Climate Impacts Group, Box 354235, University of Washington,
Seattle, WA 98195, U.S.A.
John F. Kennedy School of Government, Harvard University, U.S.A.
Dept. of Civil and Environmental Engineering, UW, U.S.A.
Now at School of Natural Resources, University of Vermont, U.S.A.
Now at USDA Forest Service, Forest Sciences Laboratory, Wenatchee, WA, U.S.A.
USDA Forest Service, Paciﬁc Northwest Research Station, U.S.A.
Richard Slaughter Associates, Boise, Idaho, U.S.A.
Abstract. The impacts of year-to-year and decade-to-decade climatic variations on some of the
Paciﬁc Northwest’s key natural resources can be quantiﬁed to estimate sensitivity to regional cli-
matic changes expected as part of anthropogenic global climatic change. Warmer, drier years, often
associated with El Niño events and/or the warm phase of the Paciﬁc Decadal Oscillation, tend to be
associated with below-average snowpack, streamﬂow, and ﬂood risk, below-average salmon survival,
below-average forest growth, and above-average risk of forest ﬁre. During the 20th century, the
region experienced a warming of 0.8
C. Using output from eight climate models, we project a further
warming of 0.5–2.5
C (central estimate 1.5
C) by the 2020s, 1.5–3.2
C) by the 2040s, and
an increase in precipitation except in summer. The foremost impact of a warming climate will be
the reduction of regional snowpack, which presently supplies water for ecosystems and human uses
during the dry summers. Our understanding of past climate also illustrates the responses of human
management systems to climatic stresses, and suggests that a warming of the rate projected would
pose signiﬁcant challenges to the management of natural resources. Resource managers and planners
currently have few plans for adapting to or mitigating the ecological and economic effects of climatic
Certain natural resources feel the inﬂuence of climatic variability and change,
and knowledge of those inﬂuences could improve long-term management of nat-
ural resources. This paper examines the inﬂuence of past climatic variability and
likely future climatic change on three key climate-sensitive resources in the Paciﬁc
Northwest (PNW), namely, water, salmon, and forests. Undergirding the work is
a retrospective analysis of connections between climatic variations and each re-
source. This retrospective approach also allows us to examine how the region’s
Climatic Change 61: 45–88, 2003.
© 2003 Kluwer Academic Publishers. Printed in the Netherlands.