Published on April 24, 2008
Climate change projections for Washington state economic impacts assessment : Climate change projections for Washington state economic impacts assessment Amy Snover, PhD Climate Impacts Group Center for Science in the Earth System Joint Institute for the Study of the Atmosphere and Oceans University of Washington April 6, 2006 University of Washington Climate Science in the Public Interest Outline: Outline Consensus on climate change Changes already observed Projected future change Regional consequences Climate Science in the Public Interest Outline: Outline Consensus on climate change Changes already observed Projected future change Regional consequences Science of climate change: Science of climate change Thousands of peer-reviewed scientific papers Intergovernmental Panel on Climate Change (IPCC) Major reports in 1990, 1996, 2001, 2007 2001 report involved 637 contributing authors, 420 peer-reviews, then another review by government experts and policy-makers Conclusions: “An increasing body of observations gives a collective picture of a warming world and other changes in the climate system.” “There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.” www.ipcc.ch: www.ipcc.ch Facts about global climate change: Facts about global climate change There is a natural greenhouse effect Humans are increasing the greenhouse effect by adding greenhouse gases to the atmosphere There is considerable evidence that Earth has warmed in the last 100 years Without drastic changes in current emissions trends, greenhouse gas concentrations will increase dramatically over the next century and beyond Source: The Intergovernmental Panel on Climate Change (IPCC), www.ipcc.ch Three “knowns” about climate change : Three “knowns” about climate change 1. There is a natural greenhouse effect Pierce Slide8: Humans are increasing the greenhouse effect by adding greenhouse gases to the atmosphere CO2: by 32% Methane: by 150% Nitrous oxide: by 17% Three “Knowns” IPCC 2001 Slide9: OSTP Three “Knowns”: HALOE H2O Convection Frequency (0.5, 1, 5, 10%) Tropopause Randel et al 2001, fig 6 Three “Knowns” 3. Effects of a changing climate are already apparent and there is likely much more to come. Slide11: Natural Climate Influence Human Climate Influence All Climate Influences “There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.” (IPCC 2001) IPCC 2001 Outline: Outline Consensus on climate change Changes already observed Projected future change Regional consequences Slide13: 3.6°F 2.7°F 1.8°F 0.9°F cooler warmer Temperature trends (°F per century) since 1920 PNW warmed +1.5 F during the 20th century In contrast: No clear 20th century trend in precipitation … Mote 2003a Slide14: Mote 2003(b) Trends in April 1 SWE, 1950-2000 Snow water equivalent trends, 1950-2000 73% of stations show a decline in April 1 snow water equivalent Decrease Increase Slide15: Nearly every glacier in the Cascades and Olympics has retreated during the past 50-150 years Photos courtesy of Dr. Ed Josberger, USGS Glacier Group, Tacoma, WA South Cascade Glacier, 1928 (top) and 2000 (right) Outline: Outline Consensus on climate change Changes already observed Projected future change Regional consequences Slide17: Global average temperature projected to rise 2.5-10.4°F by 2100 Other changes too: sea level rise, extreme events, etc. Even if CO2 emissions ended tomorrow, warming would continue through 21st century Due to atmospheric persistence of greenhouse gases Changes over next several decades are independent of emission paths Today’s choices matter for longer-term changes Source: IPCC TAR 2001 IPCC 2001 Global climate change model uncertainty emissions uncertainty Slide18: Source: IPCC TAR 2001 Pacific Northwest climate change Accelerated warming Rate = 0.2-1.0°F per decade vs. 0.15°F per decade over 20th century Possibly more in summer than winter Precipitation wetter wet season drier dry season year-to-year variability continues Figure source: CIG Climate change is more than just averages: Climate change is more than just averages frost days decreasing snowfall decreasing precipitation intensity... Outline: Outline Consensus on climate change Changes already observed Projected future change Regional consequences Washington’s economy and natural resources are sensitive to climate changes: Washington’s economy and natural resources are sensitive to climate changes we know this from experience the water cycle plays an especially prominent role in transmitting climate impacts into resource impacts “drought” – a water supply shortage – is our region’s greatest climate vulnerability Springtime snowpack will decline, especially at the warmest locations: Springtime snowpack will decline, especially at the warmest locations +2.3C, +4.5% winter precip + 4.1 ºF (2.3 ºC) & + 4.5% winter precipitation Figure source: CIG Slide23: + 4.1°F + 4.5% winter precip Springtime snowpack will decline, especially at the warmest locations Figure source: CIG Warmer winters have a negative impact on skiing in Washington: Warmer winters have a negative impact on skiing in Washington delayed season openings, a shorter ski season, and lower quality ski conditions lowest elevation (warmest) areas are impacted the most (Snoqualmie Pass and Stevens Pass) 0 20 40 60 80 100 Streamflow patterns are temperature dependent: Streamflow patterns are temperature dependent Impacts on Columbia Basin hydropower supplies: Impacts on Columbia Basin hydropower supplies Winter and Spring: increased generation Summer: decreased generation Annual: total production will depend on annual precipitation Plus: impacts on electricity demand in winter in summer NWPCC (2005) Warming climate impacts on electricity demand: Warming climate impacts on electricity demand reductions in winter heating demand smaller increases in summer air conditioning demand in the warmest parts of the region NWPCC (2005) Slide28: Oct Dec Feb Apr Jun Aug Impacts on Seattle’s water supply reduced summertime inflows, increasing the size and extending the time of the summertime inflow-demand deficit this is common to all our region’s municipal (surface) water supplies Wiley (2004) A warmer climate and flooding, stormwater & wastewater management: A warmer climate and flooding, stormwater & wastewater management At mid-elevations more precipitation will fall as rain and less as snow, leading to an increased frequency of river flooding At high elevations there are competing factors: reduced snowpack may reduce flood risks in spring elevated spring soil moisture may increase vulnerability to flooding during spring storms a warmer atmosphere holds more moisture: theory and climate models suggest an increased intensity of precipitation if WA precipitation events become more intense, it will increase the risk of urban flooding and combined sewer overflows Sea Level Rise scenarios depend on regional tectonics: Sea Level Rise scenarios depend on regional tectonics tectonic processes are causing South Puget Sound to subside and the Olympic Peninsula to uplift this means that relative sea level rise will be greatest in South Puget Sound (~3.3ft by 2100), and least near Neah Bay (~1.3ft by 2100) Slide31: Top-Down Change Agostini 2005 NOAA John Field Slide32: Source: NMFS acoustic surveys National Marine Fisheries Service acoustical surveys Slide33: 134 lb marlin caught 40 mi. west of Westport, WA, Sept 2, 2005 Photo obtained from the Seattle Times web-archives Slide34: Climate impacts on salmon must be added to existing stresses across their full life-cycle Slide35: Temperature thresholds for coldwater fish in freshwater Warming temperatures will increasingly stress coldwater fish in the warmest parts of our region A monthly average temperature of 68ºF (20ºC) has been used as an upper limit for resident cold water fish habitat, and is known to stress Pacific salmon during periods of freshwater migration, spawning, and rearing. +3.4 °F +4.1 °F Climate change impacts on Washington’s forests: Climate change impacts on Washington’s forests CO2 fertilization a transient impact Longer dry season increased vulnerability to fires & insects; reduced regeneration and growth at low-dry sites; some benefit at higher elevations Shifts in species ranges Forest fires will accelerate change climate has played a key role in recent increases in area burned average annual area burned in Washington could increase 2-5x by 2100 Ecosystem thresholds: the case of the Mountain Pine Beetle: Ecosystem thresholds: the case of the Mountain Pine Beetle a massive outbreak of the mountain pine beetle in BC has killed 100 billion board feet (approx. 9 years of harvest) low temperatures (< -10°F) limit beetle activity a recent lack of extreme cold, killing temperatures has allowed the beetle to thrive in epidemic numbers beetle killed pines in BC Photos from http://www.for.gov.bc.cal Slide38: http://www.for.gov.bc.ca/hre/bcmpb/ Warmer climate and increased CO2 impacts on agriculture: Warmer climate and increased CO2 impacts on agriculture increased crop yields – where sufficient soil moisture or irrigation water is available but crops could suffer more days of heat & moisture stress where soil moisture/irrigation water supply decreases may stimulate crop pests, pathogens, and weeds summer irrigation water supplies are likely to decline where storage capacity is limited the Yakima Basin, for example changes in crop types: new opportunities for some and lost opportunities for others different varieties of wine grapes Slide40: Climate change will force resource managers and planners to deal with increasingly complex trade-offs between different management objectives.