adapting to a changing climate - jerry knox (cranfield university)
DESCRIPTION
This presentation formed part of the Farming Futures event 'FarmWater Futures'. 30th March 2010TRANSCRIPT
Adapting to a changing clim ate
Dr. Jerry Knox
O utline
1. Impacts on agroclimate2. Impacts on potato yield and water use3. Responses - adaptation
O bserved European annual m ean air tem perature
-1.50
-1.25
-1.00
-0.75
-0.50
-0.25
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
18501860
18701880
18901900
19101920
19301940
19501960
19701980
19902000
Temperature deviation, compared to 1850-1899 average
(o C)
Annual deviations (land only)
10-year moving average (land only)
2008 10th warmest on record
1990s warmest decade in last 100 years
Clim ate w ill continue to change
Global surface temperature increase:<10% probability less than 1.5 degrees
Likely range 2.0-4.5 deg with best guess3.0 degrees
Higher than 4.5 deg cannot be excluded
Clim ate change im pact pathw ays
Clim ate variability drives irrigation dem and
0
10
20
30
40
50
60
70
80
90
100
Jan Feb Mar Apr
May Jun Jul Aug Sep Oct Nov
Dec
Rainfall (P)
Evapotranspiration (ET)
Predicted changes in evapotranspiration (ET)
Predicted changes in rainfall (NIAB, 2050s)
‐60
‐40
‐20
0
20
40
60
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Precipitation anom
aly (%) .
2050L 2050H
Long-term average agroclim ate (1961-90)
Average agroclim ate Low em issions2050s
Average agroclim ate High em issions2050s
Current w ater resource stress
(Source: PCL, 2009)(Source: EA, 2008)
Potato production and w ater resources
42%22%
20%
12%
5%
29%
28%
25%
9%
8%
In the future, potato production likely move onto new land with secure water supplies
Case studies
Farm site (2003-08)LF Papworth and Son, FelminghamMaris piper (pre-pack)Sandy loam soilOverhead irrigationScheduled for scab control and bulking
Experimental site (2003-08)Cambridge University Farm
O bserved v sim ulated yields for baseline
Predicted changes in yield (t ha-1) 2050s
Future irrigation needs (m m ) 2050s
1. Future ‘average year’ more like a current ‘dry year’
2. Irrigation schemes could fail to meet future peak irrigation demand in 50% of years
Clim ate uncertainty -im pacts on irrigation (m m )
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
100 150 200 250 300 350 400 450 500 550
Irrigation requirement (mm)
Prob
abili
ty d
ensit
y (p
er m
m)
2050L2050HActual
1995, typical dry year
Im pact on irrigation costs
Increase in daily peak• Large pumps and main pipes• More mobile irrigators needed for given area• But solid set costs are mostly not affected – drip, centre pivot
Increase in annual application• Does not necessarily impact equipment costs• Larger reservoir needed• Higher fuel and labour costs
For existing irrigators, on-farm irrigation cost increases will be proportionately smaller than irrigation need increases
W ork so far…W ork planned…
Modelling assumed unchanged practices - but there will be autonomous adaptation even if not planned adaptation
• Earlier planting and harvest dates• Change to better adapted varieties• Less use of very light soils• Move to different region – northwards and westwards• GM technology
Sum m ary -the adaptation m essage
Water is already scarce
Climate change will make it even scarcer
Adaptation will be essential – preferably plannedAdaptation reinforces current trends - many adaptations
are “no regret” - they make senseBeware of mal-adaptations - changes that climate
change render worthless
Adaptation – w hat others are doing
Building reservoirsStarting to work togetherforming ‘water abstractor groups’
Making better use of existing supplies