About the Puget Sound Institute

Climate change
projections would result in sea level rise for the northwest Olympic Peninsula, it is not
yet possible to conclusively rule out a decline in sea level for that region.
17. Short-term sea level variations can temporarily offset or accelerate trends. Sea level
can be temporarily elevated or depressed by up to a foot in winter as a result of natural
periodic cycles in climate patterns such as El Niño and the Pacific Decadal Oscillation
(NRC 2012). This variability will continue in the future.
Ocean acidification
18. Observed acidification of the global ocean. The acidity of the global ocean has increased
by about +26% since 1750. The current rate of acidification is nearly ten times faster than
any time in the past 50 million years (IPCC 2013). 15
19. Ocean acidification. The acidity of the ocean is projected to increase by +38 to +109%
(IPCC 2013) 15 by 2100 relative to 1986-2005 (or increase roughly +150 to +200%
relative to pre-industrial levels, Feely et al., 2009) as global oceans continue to absorb
carbon dioxide from the atmosphere.
20. Local changes in Ocean Acidification are modulated by upwelling and runoff. Local
conditions are also affected by seasonal upwelling of deeper Pacific Ocean water that is
low in pH and high in nutrients, transport of nutrients and organic carbon from land,
and oceanic absorption of other acidifying atmospheric gases.
Snow
21. Observed decreases in spring snowpack in the Washington Cascades. Spring (April 1 st )
snowpack fluctuates substantially from year-to-year, but declined by about −25% overall
(range −15% to −35%) in the Washington Cascades from the mid-20 th century to 2006
(Stoelinga et al., 2009; Mote et al., 2008). 16 This trend is due primarily to increasing
regional temperature and reflects the influence of both climate variability and climate
change (Hamlet et al., 2005; Pierce et al., 2008). Natural variability can dominate over
shorter time scales, resulting (for example) in an increase in spring snow accumulation
in recent decades (Stoelinga et al., 2009).
22. Observed decreases in Washington glaciers. About two-thirds of the glaciated area in
the lower 48 states (174 out of 266 sq. miles) is in Washington (Fountain et al., 2007).
Although there are some exceptions, most Washington glaciers are in decline. Declines
range from a −7% loss of average glacier area in the North Cascades (1958-1998,
15
Although the acidity of the ocean is projected to increase, the ocean itself is not expected to become acidic (i.e.,
drop below pH 7.0). Ocean pH has decreased from 8.2 to 8.1 (a 26% increase in hydrogen ion concentration, which
is what determines the acidity of a fluid) and is projected to fall to 7.8-7.9 by 2100. The term “ocean acidification”
refers to this shift in pH towards the acidic end of the pH scale.
16
These numbers indicate changes in April 1 st Snow Water Equivalent (SWE). SWE is a measure of the total amount
of water contained in the snowpack. April 1 st is the approximate current timing of peak annual snowpack in the
mountains of the Northwest.
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