Transcript Baldocchi Ca Climate Conf Climate change and ag

Climate Change and Agricultural:
Trends and Bi-Directional Impacts
Dennis Baldocchi
Department of Environmental Science, Policy and
Management
University of California, Berkeley
Outline
• Background
– Trends in Agricultural Climate
Statistics
– Processes
• Temperature
– Phenology
– Dormancy
– Extreme Events
• Elevated CO2
• Water Use
• Land Use
• Case Studies
– Winter Chill Trends in Fruit
Growing Region of CA
– Impacts of Summer
Temperature Extremes on
Crop Water Use and Fruit
Temperatures
Climatic and Environmental Variables and Statistics affecting Agriculture
•
Agricultural Temperature
–
First and Last Frost
–
Summed cold units
•
•
Summed Heat Units
–
Extreme Temperature
•
Amount
•
–
Growth, Evaporation, Leaf Temperature
Diffuse/Direct Fraction
•
Canopy Photosynthesis Efficiency
Atmospheric Humidity Deficits
–
–
Evaporative Demand
Insect and Microbial Pests
CO2
–
•
amount, duration, frequency
Sunlight
–
•
Fruit and Leaf Damage
Rainfall and Irrigation
•
•
Phenology, Growth and Fruit Production
Water Supply
–
•
Dormancy
–
•
•
Length of Growing Season
Regulates Photosynthesis, Stomatal
Regulation, Transpiration
Pollution
–
ozone
Trends in Phenology, Observed WorldWide
Timing of Apple blossom blooming in Germany
Chmielewski, et al AgForMet
Trends in Growing Season Length and Last Frost Date
Feng and Hu, 2004, J Theor Appl Clim
United States
Trend in CA, ~ Growing Season Starts ~1 day Sooner per Decade
Trends, days per Decade
Feng and Hu, 2004, J Theor Appl Clim
Role of Temperature Extremes on Rice
Grain Yield
Biomass
Spikelets
Peng et al PNAS, 2003
Almond Yield Anomaly
Almond Yield (ton acre-1)
Role of Seasonal Statistics and Combination of Temperature and Rain
David Lobell, Unpublished, Data source: CIMIS, NASS
Trends in Dry and Wet Spells
Feng and Hu, 2004, J Theor Appl Clim
United States
Managed Agricultural Landscapes in California
Change in Irrigated Lands
Christy et al 2006 J Climate
Agriculture, Land use Change and Climate
• Albedo
• Energy Partitioning into Heat and Evaporation
– Leaf Area Index
– Surface Wetness
– Surface Conductance
• Carbon Uptake and Respiration
• Climate
– Maximum and Minimum Air Temperature
– Humidity
Role of Agriculture in the Climate System
Role of Agriculture in Carbon Cycle
Agricultural Crop
Grasslands
3
2
1
2
NEE (gC m d )
-1
0
-1
R)
PA
f(a
P= PP
GP <<G
R eco
Late Snow
Tsoil (-)
Reco(-)
-2
-2
Mediterranean Grassland
Harvest
-1
NEE (gC m d )
Planting Date
time when GPP>0
Winter fallow
GPP=0
Reco=f(Tsoil,)
4
Tsoil(+), Residual Matter(+)
Reco(+)
GPP=0
-2
Grain Filling
Reco(++)
0
-2
-3
-4
-4
0
50
100
150
200
Day
250
300
350
0
50
100
150
200
Day
250
300
350
Humidity/Temperature Transition, Desert to Irrigated Crop
25
25
x=0m
38
20
3
72
Height (m)
Height (m)
72
100
15
800
10
100
15
800
10
5
5
0
10.5
x=0m
20
11.0
11.5
Mean Humidity (g m- 3)
Baldocchi and Rao, BLM 1996
12.0
12.5
0
29.0
29.5
30.0
30.5
Mean Potential Temperature (C)
31.0
Central Valley Trends in Minimum Temperature:
Partially Attributed to Land Use Change
1895
years
2005
1895
years
2005
•Moisture, from Irrigation, increases downward Longwave energy at night
•Evaporative cooling offsets daytime warming trend
Christy et al., 2006 J Climate
Elevated CO2
• Pros
– Increases Photosynthesis, short-term
– Promotes Stomatal Closure
– Increases Water Use Efficiency
• Cons
– Down-regulation in Photosynthesis, long-term
300
0.012
250
0.010
200
0.008
150
0.006
100
0.004
LE
Stomatal Conductance
50
0.002
0
0
100
200
300
400
500
CO2
600
700
800
900
0.000
1000
Stomatal Conductance (ms-1)
LE (W m-2)
Leaf Transpiration and Elevated CO2
CO2 and Crop Temperature:
Induced Stomatal Closure Increases Surface Temperature
Long et al., 2006 Science
DownRegulation of Photosynthesis and Yield Occurs with Time
Long et al 2006 Science
Case Study
• Trends in Winter Dormancy in the CA Fruit
Growing Region
• Data Sources
– CIMIS, Hourly, from 1980s
– National Climate Center Coop, Max-Min, from
1930s
Estimating Winter Chill
 chillhours  d  2  (T
ref

Tref  Tmin
2
Tmax
)
Noon
a
Tave
b
d
Tref

c
Tmin
d
chillhours
 tan   (Tref  Tmin )
2
tan  
a
6hr

b Tave  Tmin
Testing Chill Hour Sums with Daily and Hourly Data on Annual Basis
Zamora, CA
Chill Hours, max-min
2000
1500
1000
Coefficients:
b[0]: 15.00
b[1]: 0.998
r ²: 0.887
500
0
0
500
1000
1500
Chill Hours, hourly data
2000
Downward Trend in Chill Hours near Brentwood, East Contra Costa
Chill Hours, below 7.22 oC Nov1 through Feb 29
Brentwood, CA
1600
1400
1200
1000
20 year record,
CIMIS Data
800
600
400
1985
1990
1995
2000
2005
2010
2000
2005
2010
Chill Degree-Hours, below 7.22 oC Nov1 through Feb 29
Year
4000
3500
3000
2500
2000
1500
1000
1985
1990
1995
Year
Downward Trend in Chill Hours near Orland, northern Sac Valley
Orland, Ca
1800
Coefficients:
b[0] 14228
b[1] -6.711
r ² 0.234
Chill Hours, below 7.22 oC
1600
1400
1200
50+ year Record,
Coop Data
1000
800
600
400
1940
1950
1960
1970
1980
1990
2000
2010
Year
Chill Degree-Hours, below 7.22 oC
5000
Coefficients:
b[0]: 47974
b[1]: -23.01
r ²: 0.248
4000
3000
2000
1000
0
1940
1950
1960
1970
1980
Year
1990
2000
2010
Trends in Winter Chill Hour Accumulation (hours per year)
Nov-Mar, 0 to 7.22 C
42
41
40
39
38
37
36
35
-40 to -20
-20 to -15
-15 to -10
-10 to -5
-5 to 0
0 to 10
34
33
-124
-123
-122
-121
-120
-119
-118
-117
-116
-115
Projected Trends in Winter Chill
1600
Red Bluff, CA, B1
Chill Hours, below 7.22 oC
1400
1200
1000
800
600
400
200
1940
1960
1980
2000
2020
2040
2060
2080
2100
2120
Years
1800
Chill Hours, below 7.22 oC
1600
Davis, CA, B1
1400
1200
1000
800
600
400
200
0
1940
1960
1980
2000
2020
2040
2060
2080
2100
2120
Years
1600
Fresno, CA, B1
Chill Hours, below 7.22 oC
1400
1200
1000
800
600
400
200
1940
1960
1980
2000
2020
2040
Years
2060
2080
2100
2120
ET: 1054 mm
LE (W m-2)
200
150
Walnut Water Use
100
50
0
0
50
100
150
200
250
300
350
400
Day
Walnuts
2003 Climate data
250
Ta + 3C, CO2 =500 ppm
ET: 1199 mm
40
ET: 1054 mm
LE (W m-2)
LE (W m-2)
200
150
100
20
0
50
0
0
50
100
150
200
Day
-2
)
40
Ta + 3C, CO2 =500 ppm
ET: 1199 mm
250
300
350
400
-20
0
50
100
150
200
Day
250
300
350
400
Potential Change in the
Incidence of Sunburn
Walnuts
Sunlit leaves
0.06
0.05
2003 weather
Ta + 3C; CO2= 500 ppm
0.04
0.03
pdf
0.02
0.01
0.00
-10
0
10
20
Tleaf
30
40
50
Solutions
• Irrigation scheduling and soil moisture
management
• Proper choice of Crops and Environment
• Mulches and increased soil organic matter to
reduce soil evaporation and runoff
• Precision agriculture and drip irrigation
• Changes in crops, timing and rotation
• Crop Breeding for water use efficiency, reduced
dormancy
• Use of Reflectants to Increase albedo and
reduce heat stress
Summary
• Climate Change is in Motion in California
– Due to a combination of Rising Greenhouse Gases
and Landuse Change
• Long term production of valuable fruit crops is
vulnerable due to trends in reduced winter chill
– The future trends may not be linear, but could
accelerate if winter fog patterns change
• Breeding programs are needed to produce
cultivars that require less winter chill
Trends in Winter Chill Degree Hours Accumulation (degree-hours per year)
Nov-Mar, 0 to 7.22 C
42
41
40
39
38
37
36
-100 to -75
-75 to -50
-50 to -25
-25 to -10
-10 to 0
0 to 10
35
34
33
-124
-123
-122
-121
-120
-119
-118
-117
-116
-115
Daily Basis
Zamora, CA
24
Computed Chill hours
20
16
12
8
Coefficients:
b[0] 0.878
b[1] 0.905
r ² 0.805
4
4
8
12
16
Observed Chill hours
20
24