Climate Change Impacts on Puget Sound

1. Climate Change Impacts on Puget Sound Nate Mantua, Ph.D. University of Washington Climate Impacts Group School of Aquatic and Fishery Sciences July 29, 2008

2. Columbia River Basin The University of Washington’s Climate Impacts Group A NOAA-funded research and education team at the University of Washington cses.washington.edu/cig

3. My short list of key issues for climate change impacts on Puget Sound ecosystems • Variability in winds • Snowmelt runoff and flooding • Ocean temperatures • Ocean acidification • Sea level rise • I won’t talk about diseases or invasive species, but they probably belong here too

4. Fickle winds can cause large changes in upwelling habitat on short time-space scales Stonewall Banks Buoy SST June 18 - August 2 2005 17.5C on July 14 ~11C on July 20 August June July Buoy SST plot courtesy of Pete Lawson 20 July 2005 SST NOAA CoastWatch image

5. The California Current Ecosystem is dynamic because Pacific winds vary greatly from year to year Sept 1997 El Niño Sept 1998 La Niña

6. Pacific Pomfret (Brama japonica) Ocean Sunfish (Mola mola) Chub mackerel (Scomber japonicus) Pacific Bonito (Sarda chiliensis) (Pelicanus occidentalis) Exotic Species Sightings off the BC Coast During 1983, an extreme El Niño year (J. Fulton, P.B.S.) Slide provided by Kim Hyatt, DFO

7. upwelling food webs in our coastal ocean Cool water, weak stratification high nutrients, a productive “subarctic” food-chain with abundant forage fish and few warm water predators Warm stratified ocean, few nutrients, low productivity “subtropical” food web, a lack of forage fish and abundant predators

8. Sea Surface Temperature (Race Rocks lighthouse, Victoria)

9. Race Rocks Salinity and Temperature Annual mean SST and SSS phase diagram for Race Rocks lighthouse show trends toward warmer and fresher surface waters at Race Rocks

10. 21st Century PNW Temperature Change Scenarios

12. springtime snowpack will decline in the warmest locations + 4.1°F + 4.5% winter precip + 4.1 ºF (2.3 ºC) & + 4.5% winter precipitation +2.3C, +4.5% winter precip Figure courtesy of Alan Hamlet, UW Climate Impacts Group

13. The coldest locations are less sensitive to warming + 4.1°F + 4.5% winter precip Figure courtesy of Alan Hamlet, UW Climate Impacts Group

14. +3.6 to +5.4°F (+2 to +3°C) Streamflow patterns are temperature dependent A warming climate will shift runoff timing in snow fed streams. Snowmelt runoff in summer will decrease; winter flows will increase. Western Washington Precip Oct Feb Jun

15. A warmer climate and flooding • At mid-elevations, more precipitation will fall as rain and less as snow • a warmer atmosphere holds more moisture: theory and climate models suggest an increased intensity of precipitation • This combination points to an increased frequency of river flooding in fall and winter

16. Future warming will increase stratification • Observations of the past 50 years show that most of the warming of the global oceans is concentrated in the upper few hundred meters • Projections for the future point to more of the same -- upper ocean warming and increased stratification • This will likely impact the ability to supply nutrients to the photic zone and impact the timing, duration and intensity of plankton blooms

17. Window for accelerated growth of HABs in Puget Sound Rising water temperatures alone may promote earlier and longer lasting blooms of harmful algae (like Alexandrium catenella, which causes psp in Puget Sound). Stephanie Moore, NOAA/NWFSC

18. A Changing Chemical Regime for Marine Ecosystems Ocean Acidification That ‘other’ CO2 problem pH CO32- CO2(aq) Estimated aragonite saturation states of the surface ocean for the years 1765, 1995, 2040, and 2100 (Feely et al., submitted), based on the modeling results of Orr et al. (2005) and a business-as-usual CO2 emissions scenario. Wolf-Gladrow et al., 1999 As ocean calcium carbonate saturation state decreases, a concomitant reduction in calcification rates by marine organisms can occur. - reduced extension rates - weaker skeletons/shells

19. Ocean Acidification of the North American Continental Shelf NACP Coastal Survey Cruise: 11 May - 14 June 2007 Distribution of the depths of the corrosive water (aragonite saturation < 1.0; pH < 7.75) on the continental shelf of western North America from Queen Charlotte Sound, Canada to San Gregorio Baja California Sur, Mexico. On transect lines 5 and 6 the corrosive water reaches all the way to the surface in the inshore waters near the coast. Depth of corrosive waters Feely et al. 2008: Science Express

20. PNW sea level rise Mote et al 2008

21. A timely report from the National Wildlife Federation • The Sea Level Affecting Marshes Model (SLAMM) is used to project the impacts of sea level rise on Northwest coastal habitats http://www.nwf.org/sealevelrise

22. Projected Changes for a 27” slr (NWF 2007) • Region-wide, estuarine beaches inundated and eroded for a 65% loss • 44% of tidal flats lost • 13% of inland fresh marsh and 25% of tidal marsh lost

23. Projected Changes for a 27” slr (NWF 2007) • Impacts vary for different location because of the region’s variable habitat and landform types • For the areas pictured at right, impacts include substantial losses of estuarine beach, brackish marsh, and tidal swamp habitat, and substantial increases in tidal flat and saltmarsh habitat

24. Projected Changes for a 27” slr (NWF 2007) • Habitat will be converted! • beaches to tide flats; tide flats to shallow water • Freshwater marsh to saltwater marsh

25. Nearshore habitat has already undergone extreme changes due to land use (image reproduced from Sound Science 2007)

26. Puget Sound Food-webs • Puget Sound’s food-webs will be impacted, both directly and indirectly by climate-driven habitat changes • Predicting isn’t always easy! Image reproduced from Sound Science 2007

27. CO2 and Climate Change will play an important role in West Coast Marine Ecosystems • Natural patterns of variability (the annual cycle, El Niño, PDO, etc.) coordinate broad-scale changes in habitat, some aspects of which are predictable • The regional impacts of global warming are likely to cause many direct and indirect ecosystem impacts • Biogeographic shifts; match-mismatch between predators and prey; top-down, bottom-up, middle-out impacts; changes in dissolved oxygen concentrations • changing winds a major factor and a key source of uncertainty • Ocean acidification due to increasing concentrations of atmospheric CO2 poses potentially large threats to west coast food webs, but those threats are currently not well understood • Other issue I haven’t mentioned: invasive species, diseases

28. For more information • The Intergovernmental Panel on Climate Change http://www.ipcc.ch • The UW Climate Impacts Group http://cses.washington.edu/cig • RealClimate -- a “no spin zone” on climate science http://realclimate.org