Reality, magic potions & clairvoyance - NZAGRC · Leading Partners in Science Performance assumptions - dairy cattle Milk Yield Cow Weight 2012 base value 3972 463 Max Efficiency

Leading Partners in Science

Reality, magic potions & clairvoyance

Harry Clark

Director

New Zealand Agricultural GHG Research Centre (NZAGRC)

Copyright © 2010 New Zealand Agricultural Greenhouse Gas Research Centre 30 MARCH 2017 | 1


The Reality of reducing agricultural GHG emissions in New Zealand – guiding principles

• Is the mitigation option effective?

• Does the mitigation option have other impacts?

• Is the mitigation option likely to be cost-effective?

• Can the mitigation option be integrated into current & future NZ farming systems?

• What is the impact at the national scale?



Do we currently have any solutions available now?

• Increasing ‘efficiency’ reduces emissions per unit of product but reduction in absolute emissions depends on the quantity of product produced

• Several feed types have good scientific evidence that they can reduce CH4 emissions – e.g. concentrates, forage rape

• Reducing dietary N concentrations & N fertiliser use can reduce N2O emissions



Do these solutions pass the Reality test?

• Concentrate – % in diet, cost, general applicability

• Forage rape - ↑N2O, limited % in diet

• Reducing dietary N concentrations – cost, general applicability

• Reducing N fertiliser – ↓forage product, small % of emissions



Magic Potions!


Magic Potions!

• Strong Advocacy, Light Evidence

• Marketing & justification for funding/resources

• Even where results are quoted they are often in-vitro, uncontrolled, non-replicated & short term; credibility issue

• Even where credible results are presented any solution has to pass the ‘Reality’ test

• There are no shortcuts!



Clairvoyance – what will New Zealand’s agricultural emissions be in 2050?



• Scenario approach – not a forecast!!!!

• NZ inventory tool used for emissions estimates

• Based on currently available agricultural land

no major change into/out of livestock; may not be realistic

Dairy sector continues to expand at expense of sheep & beef;

relative commodity prices & water quality issues could change

this

• Individual animal performance continues to improve in all sectors

Methodology and key assumptions


Population assumptions

High dairy expansion 600,000ha + 247,000ha

Low dairy expansion235,000ha + 94,000ha

Dairy Beef Sheep Dairy Beef Sheep

2012 6.17 3.85 31.1 6.17 3.85 31.1

2050 9.13 3.24 24.91 7.71 3.61 28.01

• Assumes current pastoral land area remains constant

• Assumes dairy continues to expand at the expense of beef and sheep

• Stocking rates on existing dairy land remain constant in existing dairy areas but

increase in new conversions

• Fall in beef and sheep numbers based on reduced land area and current

stocking rates

• Populations change linearly from 2012-2050


Performance assumptions - dairy cattleMilk Yield Cow Weight

2012 base value 3972 463

Max Efficiency 2050 5500 470

Dairy Expansion and Dairy Constrained 2050 5000 470

Minimum Efficiency 2050 4500 470

• Changes in milk yield are linear

• Small increases in milk quality – linear interpolation of past changes


Nitrogen fertiliser use

Total N use

2012 base value 362,000

Dairy Expansion & Maximum Efficiency 2050 481,000

Dairy Constrained & Minimum Efficiency 2050 418,000

• N fertiliser based on fixed amounts per head


Warming is proportional to cumulative CO2 emissionsBaseline scenarios

• High or low expansion of dairy land

• High or low efficiency per animal

four baseline scenarios

• Maximum and minimum absolute emissions

• Maximum and minimum emissions intensity


Warming is proportional to cumulative CO2 emissionsBaseline scenarios: all agriculture


Warming is proportional to cumulative CO2 emissionsBaseline scenarios: by category


Warming is proportional to cumulative CO2 emissionsBaseline intensity scenarios: dairy


Warming is proportional to cumulative CO2 emissionsBaseline scenarios summary

• Absolute emissions will continue to increase

• Emissions intensity will continue to decline, but at a gradually slower rate as productivity increases

• Lifting productivity significant mitigation option for emissions intensity – but increases absolute emissions without constraints on animal numbers or total production


Warming is proportional to cumulative CO2 emissionsMitigation options modelled

• Accelerated performance (intensity only)

• Low-nitrogen:fertiliser, low-N feeds

• Additional technologies:vaccine, inhibitor, breeding, DCD

• Enhanced manure management

Not modelled: feed additives, low-methane feeds, major system change towards grain-based diets


Warming is proportional to cumulative CO2 emissionsMitigation packages: absolute(high adoption rates)

enhanced dairy expansion, high productivity constrained dairy expansion, low productivity


Warming is proportional to cumulative CO2 emissionsMitigation packages: absolute(low adoption rates)

enhanced dairy expansion, high productivity constrained dairy expansion, low productivity


Warming is proportional to cumulative CO2 emissionsMitigation packages: intensity(high adoption rates)

high productivity low productivity


Dairy population (M)

6.7 6.7 5.4 6.0

Beef population (M)

3.7 3.7 2.6 2.9

Sheep population (M)

29.8 29.8 19.4 22.4

Total emissions (Mt)

39.6 33.2 24.7 28.5

Net Zero in NZ: Report by Vivid Economics, March 2017

Source: Vivid Economics and Statistics New Zealand 2016

2014 Off-track

Innovative Resourceful


Are the results from scenario studies consistent?• Reisinger & Clark assume that dairy cow numbers will rise – forecasts based on

economic and trade models, driven by historical relationships

• Vivid scenarios explicitly assume that dairy cow populations will not rise –‘increases in heads of dairy cows is unlikely to be consistent with a 2°C world and so are not considered’

• Both suggest that large emissions reductions below BAU are possible in the future

• Both suggest that new technologies are needed for large impact

• Both suggest that a basket of technologies/practices are needed for large impact

• Future emissions scenarios depend critically on assumptions around the size of the livestock sector



www.nzagrc.org.nz

Thank you

http://www.globalresearchalliance.org/

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Reality, magic potions & clairvoyance - NZAGRC · Leading Partners in Science Performance assumptions - dairy cattle Milk Yield Cow Weight 2012 base value 3972 463 Max Efficiency