adapting to a changing climate - jerry knox (cranfield university)

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