Climate trends, variations and climate change

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Transcript Climate trends, variations and climate change

Climate Change
Bill Taylor
The Intergovernmental Panel on Climate Change
(IPCC)
“The work of the…IPCC represents the
consensus of the international science
community on climate change science. We
recognize IPCC as the world’s most reliable
source of information…and endorse its
method of achieving this consensus.”
Joint statement by Academies of Science – May 2001
www.ipcc.ch
Part 1
Evidence of climate change
Is the climate changing?
Earth’s temperature record
deschutes.gso.uri.edu/
www.studyworksonline.com
Proxy record
www.studyworksonline.com
Instrumental record
Variations in the Earth’s surface temperature
for the past 140 years
Global
Data from thermometers
Source: IPCC Third Assessment Report, 2001
Departures in temperature (°C)
from the 1961-1990 average
Variations in the Earth’s surface temperature
for the past 1000 years (N. Hemisphere)
Data from thermometers (red) and from tree rings,
corals, ice cores and historical records (blue).
Source: IPCC Third Assessment Report, 2001
Temperature trends in Canada
annual -
from 1950–1998
Daily Minimum
Units are degrees C per 49-year period. Grid squares with trends
statistically significant at 5% are marked by crosses.
Source: Zhang et al, 2000
Trends in daily minimum temperature
seasonal -
from 1950–1998
Units are degrees C per 49-year period. Grid squares with trends
statistically significant at 5% are marked by crosses.
Source: Zhang et al, 2000
20th Century warming in
Southern Canada
• Temperature increase of 0.9° C per
century
• Canada has become “less cold”
• Canada is wetter
• Shifts in snow fraction
• Large regional differences
• Large seasonal differences
Source: Zhang et al, 2000
Part 2
Physical evidence
Visible changes?
Glaciers in
retreat
Source: IPCC, Third Assessment Report, 2001
Sea-ice extent and
thickness
Northern Hemisphere
•10% reduction in
sea-ice extent during
spring and summer
• 40% reduction in
Arctic sea-ice
thickness
Source: Vinnikov et al, 1999
Source: IPCC, Third Assessment Report, 2001
Snow-cover extent and
duration
Changes in Northern
Hemisphere in 20th Century
• 10% reduction in snow
cover extent since late ‘60s
• 2 week reduction in
duration of lake and river
ice cover
Source: IPCC, Third Assessment Report, 2001
Source: R. Brown, Environment Canada
Part 3
Impacts on hydrology
Vulnerability to climate
change?
Water Management & Climate Change
in the Okanagan – CCAF Project
• Climate change
scenarios
• Hydrologic modeling
(water supply)
• Agricultural modeling
(water demand)
• Adaptation Options(cost/benefit;
stakeholder dialogue)
Supported by a grant from the Climate Change Action Fund (#A463/433),
Natural Resources Canada, Ottawa.
Okanagan Agriculture
• Wine industry
– ~$200 million sales
– Tourism
• Tree fruit
– $67 million sales
(apples = $43
million)
• % change in area
grown 1996-2001
– Apples -20%
– Grapes +193%
Source: (1) BC Wine Institute (2) BC Ministry of Agriculture, Food and Fisheries (2001 data)
Irrigation
“Agricultural sustainability in these semi-arid
regions is primarily determined by water
supply being adequate to meet demand.”
(Denise Nelisen, PARC)
18
16
14
13
Summerland
14
12
11
10
12
9
10
8
7
8
6
5
6
Thousands of acre-feet
Annual total consumption in million cubic metres
Annual water use
4
4
2
Residential consumption
2
Irrigation
Total consumption
0
1975
3
1980
1985
Courtesy: David Sellers, consultant
1990
1995
2000
1
Total consumption trendline
0
Residential trendline
2005
Irrigation trendline
Crop Water Demand
• Amount of water required
depends on
– Crop coefficients (ET)
– Length of growing season
(growing degree days)
• Area x usage for each
polygon
• Summed over all polygons
Indicator: daily maximum
temperature in growing season
Water supply (Snow Pack)
• Supply of water
during growing
season depends on
accumulation of snow
during winter
Indicators:
• Snowpack (SWE)
• Winter and spring temperature
• Snow fraction
Trends in Daily Maximum
Temperature
0.024 ºC per year
0.010 ºC per year
0.012 ºC per year
0.013 ºC per year
Daily Maximum Temperature - Summerland
Trends in snow fraction
• SF = portion of
precipitation that
falls as snow
• Based on Nov-Mar
snow and precip
• Differences in
elevation
– McCulloch – 1250m
– Penticton – 344m
Trends in snow pack
• April 1 SWE
– Declines at some
stations
– Elevation?
1780 m
• Warmer springtime!
April 1 SWE at Summerland Reservoir
vs March Tmax at Summerland
450
1280 m
400
SWE (mm)
350
300
250
200
150
100
50
0
4
5
6
7
8
9
degrees (C)
10
11
12
13
14
Onset of snow-melt
• = Date of Tavg > 0
• Based on Daily
Average
Temperature at
McCulloch (1250m)
• Advance of 11 days
over 45 years
(11 +/- 4 days)
Part 4
Climate change projections
How will climate change in
future?
Causes of climate change
•Natural factors
- Solar variability
- Volcanic dust
- Internal variability
(ENSO, PDO)
•Human factors
- Greenhouse gases
- Aerosols
- Ozone depletion
- Land use change
Global temperature response to
SRES scenarios
5.8°
1.4°
Source: IPCC, Third Assessment Report, 2001
Unprecedented warming!
Source: IPCC Third Assessment Report, 2001
o
Precipitation Change (%)
Winter Season (DJF) 2050, Lat=50 Lon=120
Climate Change
Scenarios for 50 °N,
120°W
for the 2050s
o
25
20
15
10
5
Legend
0
0
1
2
3
4
5
Mean Temperature Change (oC)
CGCM2 A21
CGCM2 B21
CSIROMk2 A21
o
Summer Season (JJA) 2050, Lat=50 Lon=120
o
Precipitation Change (%)
CSIROMk2 B21
10
HadCM3 A22
0
HadCM3 B22
-10
-20
-30
-40
0
1
2
3
4
o
Mean Temperature Change ( C)
5
Impacts on Water Supply
• Reduction in snow pack
• More rain dominated
hydrograph
• Change in volume and
timing of peak flows
Modeled SWE for Pearson Creek catchment
based on Joe Rich Creek
700
600
SWE (mm)
500
Base
400
CGCM2 A2
300
HadCM3 A2
200
CSIRO A2
100
19
61
19
71
19
81
19
91
20
01
20
11
20
21
20
31
20
41
20
51
20
61
20
71
20
81
20
91
0
Snow Water Equivalent
Stream Discharge
Source: Wendy Merritt & Younes Alila, UBC – UBC Watershed Model results
Basin crop water use in response to
climate change
Cubic metres (millions)
400
350
Total water use
300
A21
B21
250
200
historic
150
CGCM2CSIROM2-
100
HADCM3-
50
0
hist
2020
2050
2080
2020
Scenario date
Source: Denise Neilsen, PARC, Ag. Canada, Summerland
2050
2080
Costs and Benefits of Adaptation
Options in the Okanagan
• Demand-side management options
–
–
–
–
–
Public education (10%)
Irrigation scheduling (10%)
Drip irrigation (30%)
Leak detection (10 to 15%)
Domestic water metering (20 to 30%)
• Supply-side options
– Lake pumping (up to 100%)
– Increase storage (limited)
Costs range from $1,000 to $2,000 per acre-foot
The End