Adapting to a changing climate

Jerry Knox, Centre for Water Science

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Temperaturedeviation,comparedto1850-1899average

(oC)

Annual deviations (land only)

10-year moving average (land only)

2008 10th warmest on record

1990s warmest decadein last 100 years

Observed increase in European annual mean air temperature, 1860 to 2008

Impact pathways for irrigated agriculture

Human activity

Climate andweather

Increase inatmospheric CO2

concentration

Stomatal resistanceCrop growth rates

Changes in rainfalland ET (pattern and

intensity)

Crop cultivarsAreas irrigatedDepths applied

Irrigation waterdemand

Climate variability drives irrigation water demand

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Evapotranspiration (ET)

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cip

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2050L 2050H

Predicted changes in rainfall

Predicted changes in evapotranspiration (ET)

Current agroclimatevariability (1961-90)

Supplemental irrigationconcentrated in east andsouth east England – whererainfall <600 mm year

A changing climate (2020s)

By the 2020s, the irrigationneeds of central England willbe similar to those experiencednow in eastern England

A changing climate (2050s)

By the 2050s, easternsouthern and central Englandwill have irrigation needsgreater than those currentlyexperienced anywhere inEngland

Case study – impacts of climate changeon potatoes in the 2050s

Maris piper variety for pre-pack market

Sandy loam soil

Overhead irrigation

Scheduled for scab control and bulking

Impacts on water use and yield

Impacts on future irrigation needs (mm)

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3 8 14 19 24 30 35 41 46 51 57 62 68 73 78 84 89 95 100

Probability of non exceedance (%)

Irri

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Baseline

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Impacts on future irrigation needs (mm)

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3 8 14 19 24 30 35 41 46 51 57 62 68 73 78 84 89 95 100

Probability of non exceedance (%)

Irri

gai

ton

nee

d(m

m)

Baseline

2050_L

2050_H

1. Future ‘average year’ more like a current‘dry year’

2. Irrigation schemes could fail to meet futurepeak irrigation demand in 50% of years

Uncertainty in future irrigation needs

Climate impacts on potato yield

The adaption message

Water is already scarce, and climate change will make it even scarcer

Adaptation will be essential, and will reinforce current trends

Many adaptations actions will be “no regret”

i.e. they make sense now by solving existing water resource issues,

and contribute to your future adaptability

Beware of mal-adaptations - changes that climate change renders

worthless

Crop level adaptationCrop level adaptation

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

Adaption – what others are doing

Building reservoirs

Starting to work together

forming ‘water abstractor groups’

Making better use of existing supplies