Download Slide 1

UW Climate Impacts Group
Washington State
Climate Change
Impacts Assessment:
HB 1303 Key Findings
JISAO/CSES Climate Impacts Group
University of Washington
Washington State University
Pacific Northwest National Laboratory
Climate science in the
public interest
Assessment
Overview:
Study Region
Scientific progress,
assessment limitations
• Progress:
–
–
–
–
Vertical integration of climate change projections
Wide range of research areas
Narrowing of uncertainty with many climate models
Quantified impacts and ranges for decision making
• Limitations:
–
–
–
–
Modeling climate variability (interannual, decadal)
Interactions between impacts
Uncertainty in climate and projections
There may be thresholds we have yet to understand
Scenarios
changes in future temperature and precipitation for the PNW and
assessment of sub-regional climate change using regional climate
models
Projected Increases in Annual Temperature
2080s
* Compared with 1970-1999 average
2040s
2020s
5.9°F
3.5°F
2.2°F
°C
°F
Projected Changes in Annual Precipitation
* Compared with 1970-1999 average
•
Changes in annual precipitation averaged over all models are small
but some models show large seasonal changes, especially toward
wetter autumns and winters and drier summers.
Regional climate model projections
•
High-resolution models provide some key projections that
are similar across models, namely increases in extreme
precipitation in western WA and reductions in Cascade
snowpack.
•
Regional climate models provide detail about local
differences in the seasonal temperature and precipitation
changes compared to the state-wide mean obtained from
global models.
Regional climate model projections
Hydrology and Water Resources
changes in the hydrology (streamflow, snowpack, soil moisture) and
the water resources (water storage, irrigated agriculture) of
Washington
Hydrology and water resources
•
April 1 snowpack is projected to decrease by an average of 28% to
29% across the state by the 2020s, 38% to 46% by the 2040s and
56% to 70% by the 2080s Seasonal streamflow timing will shift
significantly in sensitive watersheds.
•
Due to changing seasonal streamflow, the Yakima basin reservoir
system will be less able to supply water to all users, especially
those with junior water rights. Historically, the Yakima basin has
been significantly water short 14% of the time. Without
adaptations, current projections of the medium (A1B) emissions
scenario estimate this value will increase to 32% (15% to 54% range)
in the 2020s and will increase further to 36% in the 2040s and 77%
in the 2080s. * (results are compared to 1970-2005)
Hydrology and water resources
* Compared with 1916-2006 average
Energy
changes in the demand for and production of hydropower in
Washington
Energy
•
Annual hydropower production is projected to decline by
a few percent due to small changes in annual flow, but
seasonal changes will be substantial.
•
Winter hydropower production is projected to increase by
about 0.5-4.0% by the 2020s, 4.0-4.2% by the 2040s, and
7%-10% by the 2080s (compared to water year 1917-2006)
•
Summer energy production is projected to decline by 10%
by the 2020s, 15% by the 2040s, and 20% by the 2080s. At
the same time summer cooling demands may increase by
400%
Energy
Changes in system-wide hydropower production in the Columbia system for three
future time frames: large declines in summer, slight increases in winter.
Agriculture & Economics
changes in the expected production of high-value crops in
Washington (apples, potatoes, wheat)
Agriculture
•
In the absence of water limitations, the projected impact
of climate change on eastern Washington agriculture will
not be severe. Likely changes in yields from climate alone
are increases in winter wheat (2-8% by the 2040s),
decreases in irrigated potatoes (15% by the 2040s) and
decreases in apples (3% by the 2040s).
•
However, the combination of warming and elevated CO2
could provide significant potential benefits that offset
these declines. There is some uncertainty about whether
the CO2 effect is transient, but for well managed crops in
eastern WA, the beneficial effect of elevated CO2 will most
likely be positive.
Salmon
changes in the quality and quantity of salmon freshwater habitat in
Washington
Salmon and Ecosystems
•
Rising stream temperature will reduce the quality and
quantity of freshwater salmon habitat substantially.
•
The duration of temperatures causing thermal migration
barriers and extreme thermal stress (where weekly water
temperatures exceed 70°F) are predicted to quadruple by
the 2080s.
•
Water temperatures for Western Washington stations are
generally cooler, and predicted impacts on thermal stress
are significant but less severe.
Salmon and Ecosystems
August Mean Surface Air Temperature and Maximum Stream Temperature
Historical (1970-1999)
2040s medium (A1B)
* Projections are compared with 1970-1999 average
Changes in Flood Risks
• Floods in western WA will likely increase in
magnitude due to the combined effects of
warming and increasingly intense winter storms.
• In other parts of the State, changes in flooding are
smaller, and in eastern WA projected reductions in
flood risk are common due to loss of spring snow
cover.
Forests
changes in the productivity, distribution and disturbance of forest
ecosystems in Washington
Forests
•
The area burned by fire regionally (in the U.S. Columbia
Basin) is projected to double or triple (medium scenario,
(A1B)), from about 425,000 acres annually (1916-2006) to
0.8 million acres in the 2020s, 1.1 million acres in the
2040s, and 2.0 million acres in the 2080s.
•
Due to climatic stress on host trees, mountain pine beetle
outbreaks are projected to increase in frequency and
cause increased tree mortality. Climatically suitable
habitat for pine species susceptible to mountain pine
beetle is likely to decline dramatically by the 2040s.
Forests
Changes in areas of potential pine species’ ranges in Washington. Combined with
impacts of fire and pine beetle, these areas are likely to see significant change (Data:
Rehfeldt et al. 2006, multiple IPCC scenarios).
Coasts
impacts in coastal areas of Washington
Coasts
•
A previous study involving the Climate Impacts Group found that
sea level rise in Puget Sound might be as little as 6” or as much
as 50” by 2100.
•
Sea Level Rise (SLR) will shift the coastal beaches and increase
erosion of unstable bluffs, endangering houses and other
structures built near the shore or near the bluff edges.
•
Shellfish will possibly be negatively impacted by increasing ocean
temperatures and acidity, shifts in disease and growth patterns,
and more frequent harmful algal blooms (HAB).
Urban Stormwater Infrastructure
changes in storms and demands on urban stormwater infrastructure
in Washington
Urban Stormwater Infrastructure
•
Drainage infrastructure designed using mid-20th century
rainfall records may be subject to a future rainfall regime that
differs from current design standards. Results from regional
climate models suggest increased extreme rainfall in late autumn
in western Washington.
•
Hydrologic modeling of two urban creeks in central Puget
Sound suggest overall increases in peak annual discharge over
the next half-century, but only those projections resulting from
one of the two RCM simulations are statistically significant.
Magnitudes of projected changes vary widely, depending on the
particular basin under consideration and the choice of the
underlying global climate model.
Human Health
impacts of heat waves and climate-related air pollution on health in
Washington
Human Health
•
In Washington, climate change will lead to larger numbers of
heat-related deaths due mainly to hotter summers and
population growth. For example in Seattle a medium climate
change scenario projects 101 additional deaths for people over
45 by 2025 and another 50% increase by 2045
•
Although better control of air pollution has led to improvements
in air quality, warmer temperatures threaten some of the
sizeable gains that have been made in recent years.
Human Health
Percent Increase in Risk of Death, and Number of Deaths Each Day for All NonTraumatic Causes by Heat Event Duration, Greater Seattle Area, 1980-2006.
Adaptation
fundamental concepts for planning for climate change and options
for adapting to the impacts identified in the above sectors
Adaptation Options and Opportunities
• Climate change impacts over the next few decades are
virtually certain. Impacts beyond this timeframe will be
greatly influenced by how successfully we reduce
greenhouse gas concentrations both in the near-term
and over time.
• State and local governments, businesses, and residents
are on the “front line” when it comes to dealing with
climate change impacts.
• Decisions with long-term impacts are being made every
day, and today’s choices will shape tomorrow’s
vulnerabilities.
Conclusions
Adaptation to climate change impacts is necessary because the
projected impacts within and across sectors are large.
To the extent that it can be identified, quantified, and mitigated,
uncertainty is a component of planning, not a reason to avoid
planning.
Many sectors report different impacts in different systems (e.g.,
snowpack response at low vs. high elevations, fire response in the
western Cascades vs. Blue Mountains, different species of salmonids,
different crops etc.), but the natural spatial and temporal complexity
of these systems is a key part of planning for the future.
By understanding the direction and magnitude of projected climate
changes and its impacts, we can better manage risks and capitalize on
opportunities to reduce impacts.
JISAO/CSES Climate Impacts Group
UW Climate Impacts Group
The Climate Impacts Group
www.cses.washington.ed/cig
Climate science in the
public interest