Transcript Modernisation of Weather, Climate and Hydrological Service

Best practice in using climate scenarios
and hydrological models
Model simulations of annual energy production at Kairakkum, Tajikistan
Rob Wilby, Department of Geography, Loughborough University ([email protected])
PPCR Workshop on Climate Resilience and the Energy Sector
6-7 March 2012, Barki Tojik, Dushanbe, Tajikistan
Changing mix of uncertainty elements
Precipitation
Temperature
The total uncertainty in CMIP3 global mean, decadal mean projections for the 21st
century, separated into three components: internal variability (orange), model
uncertainty (blue) and scenario uncertainty (green). Source: Hawkins and Sutton (2010)
PPCR Workshop on Climate Resilience and the Energy Sector
6-7 March 2012, Barki Tojik, Dushanbe, Tajikistan
Cascading uncertainties
Future
society
The cascade of uncertainty
GHG
emissions
Climate
model
Regional
scenario
Impact
model
Local
impacts
Adaptation
responses
Envelope of uncertainty
Source: Wilby & Dessai (2009)
PPCR Workshop on Climate Resilience and the Energy Sector
6-7 March 2012, Barki Tojik, Dushanbe, Tajikistan
Winter temperatures
(four GCMs)
Winter temperature
bias (four GCMs)
Hard truths
Three big assumptions:
1. Skill at simulating the
present climate implies
skill at predicting the
future climate
CMIP3 average
Source: Knutti (2008)
CMIP3 average
2. Agreement amongst
climate models boosts
confidence in
predictions
3. All known regional
climate forcings are
included in the climate
prediction
Is there another way?
PPCR Workshop on Climate Resilience and the Energy Sector
6-7 March 2012, Barki Tojik, Dushanbe, Tajikistan
Strategy 0: Conventional scenario-led
20
15
10
Percent change
5
0
-5
-10
-15
-20
-25
-30
5
25
50
75
95
Median
Dry Scenario
Wet Scenario
Climate change flow factors (2020s) for the River Itchen at Highbridge. Data source: UKWIR (2007)
PPCR Workshop on Climate Resilience and the Energy Sector
6-7 March 2012, Barki Tojik, Dushanbe, Tajikistan
Strategy 1: Demand management
PPCR Workshop on Climate Resilience and the Energy Sector
6-7 March 2012, Barki Tojik, Dushanbe, Tajikistan
Strategy 2: Modify operations
Zero
Historic
Licence
ROC
Smart
Harms macroinvertebrates
(days/yr)
250
200
150
100
50
0
1961-1990
1901-1930
1931-1960
1991-2009
DRY
WET
Mean annual frequency of ecologically harmful flows (<224 Ml/d) in the River Itchen
under various abstraction license conditions, climate variability and change.
Source: Wilby et al. (2011).
PPCR Workshop on Climate Resilience and the Energy Sector
6-7 March 2012, Barki Tojik, Dushanbe, Tajikistan
Strategy 3: Delay decision/investment
1961-1990
1921-1990
140
Detection times (years from 1990) for
summer low flows in the River Itchen
using two different periods to estimate
variance (1961-90 and 1921-90).
Detection time (years)
120
100
80
60
40
20
0
0
10
20
30
40
50
Detection trend (% change)
Source: Wilby (2006)
PPCR Workshop on Climate Resilience and the Energy Sector
6-7 March 2012, Barki Tojik, Dushanbe, Tajikistan
60
70
Strategy 4: Accept lower levels of performance
The business as usual scenario for East Devon: the fraction of CP.net projections that fail
to meet average water demand in October under SRES A1B. Source: Lopez et al (2009)
PPCR Workshop on Climate Resilience and the Energy Sector
6-7 March 2012, Barki Tojik, Dushanbe, Tajikistan
Strategy 5: Evaluate adaptation portfolios
Failure rate (% climate model runs)
Business as Usual
Demand
Reservoir
Demand+Reservoir
40
35
30
25
20
15
10
5
0
1960-89 2020-29 2030-39 2040-49 3050-59 2060-69 2070-79
Modelled water supply failure rates (%) in East Devon, UK with no adaptation to climate change (Business as Usual),
15% reduction in water consumption (Demand), 18% increase in storage capacity (Reservoir), or demand reduction
combined with increased storage (Demand+Reservoir). The results are based on 246 climate model runs under SRES
A1B emissions from the CPDN experiment. Without adaptation the system failure rate exceeds 35% by the 2070s, but
with both demand reduction and increased reservoir capacity is less than 10%. Source: Lopez et al (2009).
PPCR Workshop on Climate Resilience and the Energy Sector
6-7 March 2012, Barki Tojik, Dushanbe, Tajikistan
Strategy 6: Improve asset/network resilience
*
*Security & Emergency Measures Direction
Resistance to +20% flood
Resilience to +20% flood
Source: Henriques & Spraggs (2011)
PPCR Workshop on Climate Resilience and the Energy Sector
6-7 March 2012, Barki Tojik, Dushanbe, Tajikistan
Strategy 7: Apply safety margin(s)
PPCR Workshop on Climate Resilience and the Energy Sector
6-7 March 2012, Barki Tojik, Dushanbe, Tajikistan
Concluding remarks
• Climate models best
used for sensitivity tests
• Plenty of low regret
measures (hydrometry)
• Seasonal forecasting
more tractable
• System models useful
for evaluating options
PPCR Workshop on Climate Resilience and the Energy Sector
6-7 March 2012, Barki Tojik, Dushanbe, Tajikistan