The impact of projected climate change on Monaro farms.
Doug Alcock
Livestock Officer (Sheep and Wool)
Climate Change Adaptation in Southern Australian Livestock Industries Project
Southern Livestock Adaptation 2030
• National Project
• Uses modelling of – Climate– Pasture / Livestock Systems
• Compares current systems (1971 – 2000) with the same system in a projected climate (2030)
• Looking for adaptations to reduce impacts
What is a Global Climate Model?Global climate models (GCMs) combine knowledge of
Physics, Fluid Dynamics and Chemistry to describe how
– atmosphere,
– oceans,
– Land
– Volcanic activity
– living things
– ice
– Solar energy
affect each other and Earth's climate.
Turning Global Scale Modelling into local projected weather!
• GCM,s operate as a broad brush.– Around 200km resolution
• Each cell gives a regional scale projection
How can we assess the likely impact?
• Just as with projecting climate change modelling is the only way.
• One appropriate model is GrassGro
How will plants respond to increased CO2
Leaf Photosynthesis Leaf Water Loss
• Increased photosynthesis in C3 grasses and legumes (growth)• Reduced water use • Lower crude protein in grasses (higher CO2 availability dilutes Nitrogen)
Relative Assimilation Rate
0.90
0.95
1.00
1.05
1.10
1.15
1.20
350 400 450 500 550 600 650 700
C3 Grass, Legume
C4 Grass
Reference Stomatal Conductance (m/s)
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
350 400 450 500 550 600 650 700
C3 Grass
C4 Grass
Legume
Base Farm System
• Merino Ewes
• 2.5 ewes/ha
• Nov Shorn
• Unfertilised native pasture on Stony Basalt.– Poa, Stipa, legume, annual grass.
• Sell progeny at 14 months
• Feed to maintain CS 2.
Bungarby’s weather data past and 2030
Annual Rainfall Annual Max / Min temperature
1971 to 2000 544 mm 18.3 C / 4.8 C
2000 to 2009 451 mm 19.1 C / 4.8 C
CCSM (USA) 605 mm (+11%) 19.5 C / 5.9 C
HadGEM1 (UK) 561 mm (+3%) 19.1 C / 5.7 C
ECHAM5-OM (German) 439 mm (-19%) 19.7 C / 5.7 C
GFDL 2.1 (USA) 488 mm (-10%) 19.5 C / 5.9 C
CCSM 3.0 HadGEM1 ECHAM5-OM GFDL 2.1
-5
0
5
10
15
20
25
30
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Monthly Ave. Temp compared to “1971 -2000”T
empe
ratu
re °
C
SUSTAINABILITY - EROSION
Source: FERTILISER: A key to Profitable Livestock Production & Sustainable Pastures
• SOILLOSS software - DLWC
CCSM 3.0 HadGEM1 ECHAM5-OM GFDL 2.11970 - 2000
Annual Minimum Ground Cover @ 2.5 ewes/ha
Median
Bottom 25% of years
Top 25% of years
Middle 50% of years
Baseline @ 2.5 ewes/ha
13.8% of the time below 80% GC
70% of years Min GC > 80%
Echam @ 2.5 ewes/ha
30% of years Min GC > 80%
46.7% of the time below 80% GC
Echam @ 0.7 ewes/ha
63% of years Min GC > 80%
13.8% of the time below 80% GC
Merino breeding past and future
Median Annual pasture kgDM/ha
Sustainable Stocking Rate
Average Profit/ha
1970 to 2000 5833 2.5 ewes/ha $72
2000 to 2009 4717 2.5 ewes/ha(1.5 ewes/ha)
$52($8)
CCSM 3.0 6697 2.6 ewes/ha $89
HadGEM1 6720 2 ewes/ha $46
ECHAM5-OM 4258 0.7 ewes/ha -$31
GFDL 5712 1.6 ewes/ha $20
Projected profit for merino breeding at Bungarby
CCSM 3.0 HadGEM1 ECHAM5-OM GFDL 2.11970 - 2000
2000
2001 2002
2003
2004
2005
2006
2007
20082009
1.5/
ha
2.5/
ha
Some other locations and enterprises
• Beef production near Nimmitabel– British Breed– Weaner Steer with heifers retained to yearling– Improved pasture (Fescue / Sub. Clover)– Fertilised deep duplex Granite soils
• Merino’s west of Bombala.– Self replacing merino flock – Cocksfoot/Sub with some cork-screw and annual
grasses.– Fertilised deep loamy gradational soil (metasediment)
Projected Pasture Growth at Nimmitabel
0
10
20
30
40
50
60
70
80
1-Ja
n15
-Jan
29-J
an12
-Feb
26-F
eb12
-Mar
26-M
ar9-
Apr
23-A
pr7-
May
21-M
ay4-
Jun
18-J
un2-
Jul
16-J
ul30
-Jul
13-A
ug27
-Aug
10-S
ep24
-Sep
8-O
ct22
-Oct
5-N
ov19
-Nov
3-D
ec17
-Dec
Kg
Dry
Mat
ter/
ha/
day
CCSM 3.0 HadGEM1 ECHAM5-OM GFDL 2.11971-2000
Profit
CCSM 3.0 HadGEM1 ECHAM5-OM GFDL 2.11970 - 2000
0.6 cows/ha
0.8 cows/ha
0.6 cows/ha
0.5 cows/ha
0.7 cows/ha
Some other locations and enterprises
Merino’s west of Bombala.– Self replacing merino flock – Cocksfoot/Sub with some cork-screw and
annual grasses.– Fertilised deep loamy soil
Bombala projected pasture Growth
0
10
20
30
40
50
60
70
80
1-Ja
n15
-Jan
29-J
an12
-Feb
26-F
eb12
-Mar
26-M
ar9-
Apr
23-A
pr7-
May
21-M
ay4-
Jun
18-J
un2-
Jul
16-J
ul30
-Jul
13-A
ug27
-Aug
10-S
ep24
-Sep
8-O
ct22
-Oct
5-N
ov19
-Nov
3-D
ec17
-Dec
Kg
Dry
Mat
ter/
ha/
day
CCSM 3.0 HadGEM1 ECHAM5-OM GFDL 2.11971-2000
Projected profit for merino ewes at Bombala
CCSM 3.0 HadGEM1 ECHAM5-OM GFDL 2.11970 - 2000
4 ew
es/h
a
4.3
ewes
/ha
3.1
ewes
/ha
1.8
ewes
/ha
2.1
ewes
/ha
Possible impacts without adaptation
• Lower ground cover
• Lower sustainable carrying capacity
• Lower profits/ha.– BUT
• Not necessarily the case for all locations and all climate projections?
Possible Adaptations
• Drought lots (ground cover management)
• Genetic improvements
• Grazing management
• New species
• Enterprise changes
• Lambing / calving time
+ 10% Fleece weight @ -0.5 µm
CCSM 3.0 HadGEM1 ECHAM5-OM GFDL 2.11970 - 2000
4 ew
es/h
a
4.3
ewes
/ha
3.1
ewes
/ha
1.8
ewes
/ha
2.1
ewes
/ha
Top Related