The effects of climate change are being felt across British Columbia. Given that climate is the most important determinant of crop suitability for a given location, climatic change has and will affect which crops can most profitably be grown in BC and where. Crop suitability modelling uses our understanding of growing season requirements, phenological development, and/or critical temperature thresholds for individual crops to determine their suitability across the landscape. Model output using historical and future climate data can help the agricultural sector anticipate the effects of climate change on crop suitability, manage risks and adapt. There are a number of approaches to crop suitability modelling. Agriculture and Agri-Food Canada’s Land Suitability Ratings (LSRS) is used to predict the suitability of commercial field crops across the landscape; recent work using LSRS under a range of future climate scenarios suggests that crop suitability for corn may initially improve in the Fraser Valley up to the mid-century but that increasing temperatures will reverse this trend beyond 2050. Similarly, crop suitability modelling for sweet cherry, driven by modules for dormancy, spring phenology and growing season heat requirements, has shown that recent warming has extended the suitable growing region for sweet cherries northward and upslope; climate projections suggest that the Cariboo region may become available for cherry cultivation by the mid-century. In order to support BC’s agricultural sector into the future, expansion of transportation corridors and irrigation infrastructure will likely be required, as will a comprehensive assessment of the available irrigation water supply.

1. Changing climate,
shifting crops
How might climate change affect the crops we grow in
the Okanagan Valley?
Denise Neilsen, Scott Smith, Grace Frank, Istvan Losso (AAFC, retired);
Alex Cannon; Ron Fretwell; Molina Ith-Tek

2. Our climate is changing…
0
5
10
15
1916 1936 1956 1976 1996 2016
Annual number of days over
35°C
0
5
10
15
20
25
1916 1936 1956 1976 1996 2016
Annual number of days less
than -20°C
Environment Canada data for Summerland, BC
https://www.cbc.ca/news/technology/greenhouse-gases-
1.5371968

3. Climate determines the types
of crops we can grow…
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Cartoonstock.com

4. We can use modelling to help us
anticipate changes in crop
suitability across the landscape…

5. 1. Suitable sites
 Slope <30%
 Soil depth > 50 cm
 Well-drained
 < 60 % stones
 Low salinity
Neilsen et al. 2017. Modelling changing suitability for tree fruits in complex
terrain. Acta Hortic. 1160:207–214

6. 1. Suitable sites
 Slope <30%
 Soil depth > 50 cm
 Well-drained
 < 60 % stones
 Low salinity

7. 2. Weather data - daily
(500 m resolution)
Minimum
temperature,
December 29th,
1968
Maximum
temperature,
July 30th, 2003
Neilsen et al. 2017. Modelling changing suitability for tree fruits in complex
terrain. Acta Hortic. 1160:207–214

8. 2. Weather data
- Agro-climatic indices
Growing season length
(frost-free period)
0
2800
1200
800
400
2400
2000
1600
Growing degree days
Neilsen et al. 2017. Modelling changing suitability for tree fruits in complex
terrain. Acta Hortic. 1160:207–214

9. 3. Crop suitability models
SPRING:
Do temperatures get cold enough to damage flower buds?
GROWING SEASON:
Are there enough warm days for the fruit to reach maturity?
Does get hot enough to damage fruit?
AUTUMN & WINTER:
Do temperatures get cool enough to allow trees to complete dormancy
requirements?
Do temperatures get cold enough to damage flower buds?
Do temperatures ever drop below -30 C?
Neilsen et al. 2017. Modelling changing suitability for tree fruits in complex
terrain. Acta Hortic. 1160:207–214

10. Changing distribution of sweet
cherry suitability
Climate AND soil/landscape suitable
Climate suitable but soil/landscape unsuitable
Unsuitable
Neilsen et al. 2017. Modelling changing suitability for tree fruits in complex
terrain. Acta Hortic. 1160:207–214

11. But what about crop
suitability into the future?
 Canadian Earth System Model 2 (CanESM2)
 ‘Representative concentration pathway’ (RCP) 8.5 (radiative
forcing of 8.5 W m-2)
 Used to model past and project future daily temperatures for the
Okanagan Valley
 50 ‘realisations’ driven by CanESM2
 Each ‘realisation’ begins in 1950, using a randomly generated
‘seed’, and is run until 2100
 Daily climate data generated at 500 m2 spatial resolution

12. Sweet cherry suitability
– 1950s
Suitable 21-30
times out of 50…
Suitable 0-10 times out of 50…
Suitable 11-20 times out
of 50…

13. Suitable 41-50
times out of 50…
Suitable 31-40
times out of 50…
Sweet cherry suitability
– 2000s

14. Sweet cherry suitability
– 2050s

15. Will fruit be damaged by heat?
Do temperatures drop below -30 C?
Will flower buds be frozen in the
fall/winter?
Is the growing season long enough
for fruit to mature?
Will flowers be frozen in the spring?
Are dormancy requirements met?
What is driving the shift in sweet
cherry suitability?

16. Will fruit be damaged by heat?
Do temperatures drop below -30 C?
Will flower buds be frozen in the
fall/winter?
Is the growing season long enough
for fruit to mature?
Will flowers be frozen in the spring?
Are dormancy requirements met?
What is driving the shift in sweet
cherry suitability?

17. So… is climate change is good for
agriculture in the Okanagan Valley?

18. Insects and pests…
Pest/Disease Hosts
Suspected
Year of
Introduction
into BC
Apple clearwing moth
(Synanthedon myopaeformis)
All tree fruits, mountain ash,
hawthorn
2000
Spotted wing drosophila
(Drosophila suzukii)
Tree fruits and berries 2009
https://www.bctfpg.ca/ifp-organics/invasive-alien-pests/

19. 2015 2016 2017 2018 2019
Flood
Wildfire
Drought
Extreme events…
www.bclocalnews.com/news/
www.ctvnews.ca/canada

20. 0
50
100
150
200
250
300
350
Bonaparte
Cariboo
Comox
Cowichan
FraserValley
Kettle
Kootenays
Lillooet
Nicola
N.Okanagan
N.Thompson
Okanagan
Pemberton
SalmonRiver
Similkameen
S.Thompson
S.GulfIslands
MLx1000
Historic 1960-2000
Increase due to land use change
Increase due to climate change
Neilsen et al. 2018. Frontiers Environ Sci. Landscape based
agricultural water demand modeling – a tool for water
management decision making in BC, Canada. 1160:207–214
Irrigation water needs…
Indicators of climate change for BC. 2016
update.
https://www2.gov.bc.ca/gov/content/environ
ment/climate-change/adaptation/impacts

21. Changing climate, shifting
crops…
 Climate is changing in the Okanagan
 Crop suitability is shifting (sweet cherries)
 Modelling suggests that crop suitability will change
dramatically in the next few decades
 Cold temperatures expected become less limiting to
fruit production
 Fruit production may become limited by other factors
(e.g., heat; pests and disease; smoke; availability of
irrigation water)
 What can we do to prepare?
 How can we adapt?
Denise Neilsen, Scott Smith, Grace Frank, Istvan Losso (AAFC, retired);
Alex Cannon; Ron Fretwell; Molina Ith-Tek

22. Suitable 41-50
times out of 50…
Suitable 31-40
times out of 50…
Sweet cherry suitability
– 2000s

23. 3. Crop suitability models
Risk
SPRING:
Do temperatures get cold enough to damage flower buds? >2/10 yr to
>5/10 yr
GROWING SEASON:
Are there enough warm days for the fruit to reach maturity? >3/10 yr
Does get hot enough to damage fruit? >5/10 yr
AUTUMN & WINTER:
Do temperatures get cool enough to allow trees to complete
dormancy requirements?
>3/10 yr
Do temperatures get cold enough to damage flower buds? >4/10 yr
Do temperatures ever drop below -30 C? >0/10 yr
Neilsen et al. 2017. Modelling changing suitability for tree fruits in complex
terrain. Acta Hortic. 1160:207–214