Schindler presentation Part A – PDF

Transcription

Schindler presentation Part A – PDF
Western Canada’s Freshwater in a Changing Climate
D.W. Schindler
N. America in a “Greenhouse
Dominated” World?
2 x CO2
Current
4 x CO2
Environics Canadian Poll 28 Sept 2015
Why?
Economics as a Religion?
Silencing
Science and
Environmental
Groups?
Friends of Science Billboard in Calgary
Contrarian Propaganda?
The Myth of Abundance:
Canada has a lot of water
Three million lakes
Several great lakes
• But
Average precipitation only slightly exceeds
evaporation, so most large water bodies are
renewed very slowly.
In the past, evaporation has exceeded
precipitation in many periods, so that lake levels
decline over time
.
Table 1. Renewable water resources for five
countries with large water supplies
Supply (km3 per Percentage of
year)
world supply
Brazil
5,418
12.4
Russian
Federation
4,313
10.0
Canada
2,850
6.5
United States
2,818
6.4
China
2,812
6.4
Schindler 2009 Limnol. Oceanogr., Modified from Sprague (2007).
60% of
Global
standing
water is in
Boreal regions
Ave. Annual Runoff, mm
unknown
100-199
50-99
<50
Adapted from Hydrological Atlas of Canada, 1978
% of initial flow
Relative change in summer flow in the Peace and Oldman Rivers
At Peace River and Lethbridge, AB
200
Peace River (Peace River)
- 42.1%
180
Oldman River (Lethbridge)
- 57.1%
160
140
120
100
80
60
40
20
0
1910
1920
1930
1940
1950
1960
Year
Schindler and Donahue 2006 PNAS
1970
1980
1990
2000
Relative change in summer flow in the South
Saskatchewan River at Saskatoon, SK
160
140
% of initial flow
120
(-83.6%)
100
80
60
40
20
0
1910
1920
1930
1940
Schindler and Donahue 2006 PNAS
1950
1960
Year
1970
1980
1990
2000
Irrigation Water Use by Province-2010-Stats Canada
Water Quality- S. Sask. River
31 reaches- Alberta Environment
Levels- Endorheic Prairie Lakes
D. Sauchyn et al. PARC project
Table 2. Historical changes in yearly persistence and maximum depth of snowpacks in the WPP
(Environment Canada CDCD database).
Days with snowpack (yr-1)
Site
Ft Smith
Ft Chipewyan
Slave Lake
Banff
Calgary
Medicine Hat
Lethbridge
Prince Albert
Saskatoon
Regina
Period
1956-2003
1963-1993
1971-2003
1956-2003
1956-2003
1956-2003
1962-2003
1956-2003
1956-2003
1956-2003
Absolute
change
-7.7
N/S
-39.0
N/S
6.3
-25.3
N/S
-16.2
-23.3
-24.0
%
Change
-3.6
-24.7
4.4
-23.1
-9.4
-14.3
-15.0
Maximum snowpack
Absolute
change (cm)
N/S
N/S
-26.8
-32.3
N/S
-9.9
-18.3
-29.8
-10.4
-32.4
%
Change
-54.1
-61.3
-38.1
-63.5
-52.4
-31.1
-54.7
Schindler and Donahue 2006 PNAS
Schindler and Donahue
2006 PNAS
Bow Glacier in 1897…
Source: John Collie,
Whyte Museum, Banff AB
… and in 2002
(Source: Graeme Pole, 2003)
Robson Glacier
Clarke et al. 2015 Nature Geosciences
Modeled changes in mean annual temperature in the western
Canadian Prairie Region
(CGCM-2A; CCIS Project, University of Victoria, Canada
12
Mean annual temperature (C)
Baseline
2010-2039
2040-2069
2070-2099
Mean
10
+ 6.5° C from 1961 – 1990 average
8
6
4
2
0
1950
1970
1990
2010
2030
Year
Schindler and Donahue 2006 PNAS
2050
2070
2090
2110
2090-2099
Fire Severity – NRCan
Greenland Ice Loss-NOAA

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