Global Warming: Potential Effects on National Parks in the Pacific Northwest - PowerPoint PPT Presentation

Loading...

PPT – Global Warming: Potential Effects on National Parks in the Pacific Northwest PowerPoint presentation | free to download - id: 5725ff-NjE0Y



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Global Warming: Potential Effects on National Parks in the Pacific Northwest

Description:

Global Warming: Potential Effects on National Parks in the Pacific Northwest Cliff Mass, Department of Atmospheric Sciences University of Washington – PowerPoint PPT presentation

Number of Views:134
Avg rating:3.0/5.0
Slides: 26
Provided by: Cliffo70
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Global Warming: Potential Effects on National Parks in the Pacific Northwest


1
Global Warming Potential Effects on National
Parks in the Pacific Northwest
  • Cliff Mass,
  • Department of Atmospheric Sciences
  • University of Washington

2
Global Warming and the Northwest National Parks
  • Some potential impacts that have been mentioned
  • More windstorms, with increased damage to forests
    and coastal zones
  • Heavier rain, with more flooding events.
  • Reduced snowpack, and earlier spring melt.
  • Reduction in number and extent of glaciers.

3
Questions
  • Have we seen such impacts during the past few
    decades?
  • What should we expect during the remainder of
    this century?

4
The Bottom Line
  • Global warming is an extraordinarily serious
    global issue, but some areas will have lesser or
    greater effects.
  • The Northwest may well be a location where GW
    effects are delayed and weaker than the global
    average.
  • At this point in time, we are not able to
    demonstrate that global warming has produced
    measurable impacts on Northwest weather and
    climate.

5
The Bottom Line
  • The impact of global warming over the Northwest
    during the next few decades is not clear.
  • Impacts, specifically on snowpack and glacier
    extend, should be large by the middle to end of
    the century.

6
Floods
  • The November 6, 2006 floods at Mount Rainier and
    the December 3, 2007 flooding of Chehalis and
    Centralia has sensitized us to this threat.
  • The hand-waving argument is that warming
    temperatures will result in more water vapor in
    the atmosphere, heavier rain, and more floods.
  • Reality is much more complicated.

7
What does the data show?
Coastal Rainfall The trend in the number of
events greater than two inches over two days from
1950-2000
Increasing Trend
Decreasing Trend
California Oregon Washngton Canada
8
Trend in the top 60 storms 24h rainfall
9
High Resolution Global Warming Simulations
Looking to the Future
10
(No Transcript)
11
(No Transcript)
12
(No Transcript)
13
Its Not So Simple
  • Flooding is associated patterns called
    Atmospheric Rivers.a.k.a. the Pineapple
    Expresswhich are closely associated with the the
    jet stream.

14
Another possibility
  • Most most models suggest the jet stream will
    weaken and move poleward under global warming.
  • Will the hose---the atmospheric rivers move
    with it? Is that is what is happening in Oregon?
  • A lot of uncertainty exists.

15
What about other weather elements influencing the
parks?
  • Major Northwest windstormslike the Columbus Day
    Storm or the Chanukah Eve Stormare closely
    associated with the jet stream.
  • Unlike hurricanes their energy source is
    horizontal temperature contrasts, not warm
    water.
  • Climate models suggest that the jet streamand
    associated temperature contrasts, will weaken and
    more northward.
  • Implication weaker and farther north storms in
    the midlatitudes
  • Interestingly, the number of major windstorms in
    Oregon has apparently decreased.

16
Declining snowpack due to global warming?
  • Major issue in the popular threat and among some
    politicianssome claiming we have already lost
    50!

From Mote et al 2006
17
Washington-wide snowpack since 1950, Relative to
1971-2000 normal
Snowpack in usual maximum month
18

Washington-wide snowpack period of
record, Relative to 1971-2000 normal
Snowpack in usual maximum month
19
Cascade Snowpack has INCREASED during the past 30
yrs
1976-2007 Trends in 1 Apr SWE for Elevation
Quartiles (EQs)
EQ4 7.1 EQ3 9.4 EQ2
7.8 EQ1 6.4
EQ4
High
EQ3
EQ2
EQ1
Low
Stoelinga et al 2008. Time series of elevation
quartile (EQ)-averaged 1 April SWE (in mm)
measured at snow course during the period
1976-2007. Elevation ranges for the four
quartiles are (1) 792-1119 m (2) 1119-1288 m
(3) 1288-1542 m and (4) 1542-1981 m. Dashed
lines show best-fit lines for each EQ. Also
listed are the 1976-2007 trends for each EQ (as
percent of the 1961-1990 mean).
20
Pacific Decadal Oscillation (PDO)
PDO is thought to be a natural mode of
atmospheric variability Negative phase of PDO
associated with greater snowpack in NW.
21
A Favored Area?
  • The Northwest is downwind of the eastern Pacific
    and thus our snowpack is controlled by the
    Pacific temperatures.
  • The eastern Pacific has not warmed up during the
    past 30 years.
  • Global climate models suggest the eastern Pacific
    will warm more slowly than most locations.

22
-1.4
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Air Temperature Trend (1979-2005)
Change in Surface Air Temperature (C) from
1979-2008
23
Climate Model Output for 2100
24
Averaging a collection of the best climate models
over the Pacific Suggests the Same Thing for the
Future
(a) SST
(b) Tsfc
(c) T850
SST
850 mb
0.0
0.2
0.4
0.6
0.8
1.0
2.0
3.0 C
Air Temp
Stoelinga, Albright and Mass 2008 Predicted
linear trend of November-March mean temperature
for 2000 to 2025 (C), as predicted by the
ensemble of climate models used in the IPCC AR4
report. Shown are the ensemble means of (a)
sea-surface temperature, (b) surface air
temperature, and (c) 850-hPa temperature.
25
Summary
  • Global warming is certain, the question is its
    magnitude and regional effects.
  • The magnitudes of the changes will vary
    geographically, and the Northwest may see
    weakened and delayed effects, because of our
    location downstream of the Pacific, and the
    nature of our storms.
  • Global warming is a serious, but complicated
    issue, and some of the ideas being thrown around
    by the popular press and well-intentioned but
    misinformed people are not necessarily correct.
  • Little concrete evidence at this time of any
    major global warming threats to the region or the
    parks during the next several decades
About PowerShow.com