Friday, March 29, 2024

PULPIT: Forests only a temporary measure

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The recent Parliamentary Commissioner for the Environment report Farms, Forests and Fossil Fuels is a breath of fresh air, which looks holistically at and puts in historical context a number of our land use sustainability issues.
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Further, it presents a coherent way forward, which is particularly relevant given Government consultations on both the Emissions Trading Scheme and Zero Carbon Bill, together with general public concern about water quality and biodiversity. 

The logical application of the latest science in commissioner Simon Upton’s report is in sharp contrast to the ideological basis of most public submissions and the simplistic approach being presented by the Government’s Interim Climate Change Committee.

The New Zealand economy has always been based on agriculture, which has demonstrated over time to be remarkably resilient and adaptable. 

A family farm with an inter-generational investment horizon has encouraged innovation and development with, for example, typically 50% of dairy farm revenue spent in local regions (NZ Institute of Economic Research report to the Dairy Companies Association). 

However, that has resulted in considerable modification of the landscape with the associated impact that can have on water quality.

It is disappointing to see a Government claiming to have a regional focus appearing to blindly consider major policy changes contrary to science. Without following science it will all be all pain without enduring gain. 

Interim measures mooted by the ICCC to impose low-level taxes at processor level will not influence farm behaviour and risks being the Trojan horse for larger imposts.

Upton comprehensively addresses the impact of short-term gases, principally methane, on global warming. 

The oft-repeated claim that agriculture contributes 48% of NZ emissions is based on a simplistic, arbitrary assumption of carbon equivalence known as GWP100. It has been adopted internationally because it is simple and is reasonable for most countries, which have insignificant biological emissions. 

For NZ it is highly misleading to equate release of persistent CO2 from fossil fuels accumulated over geological time with methane from a ruminant stomach accumulated by photosynthesis in the previous month, with a twelve-year half-life. 

It is acknowledged that each molecule of methane does cause significantly greater warming than CO2. 

Upton quotes Allen et al (Oxford University) who has shown that GWP (as opposed to GWP100) is a much better predictor of actual radiative forcing (warming). The principal drivers of GWP are the accumulated CO2 concentration and the annual rate of change in concentration of short-lived gases. 

Using GWP, methane’s actual contribution to NZ’s warming since 1990 reduces from above that of CO2 to less than half CO2.

More importantly, the GWP formula means that to hold 2050 warming to the Paris accord’s goal to limit warming to a 1.5C increase above pre-industrial levels, CO2 should be reduced to zero because any emissions will result in ongoing warming in perpetuity. This means NZ use of fossil fuels must be phased out or international credits bought. 

A sector that has not attracted much attention but is possibly the most problematic is international tourism, often touted as a replacement for agriculture.

Government-controlled Air NZ has, without scientific justification, submitted to zero carbon consultation that methane concentrations should be reduced to zero. 

However, Allen et al show short term gases, of which methane is the most important, need only to have their rate of release modestly reduced. For biologically derived methane a 10% reduction over 30 years would suffice to achieve the 1.5C. A greater reduction target (IPCC estimated 35%) would apply to fossil derived methane.

GWP100 refers to warming in 100 years.

Upton highlights the focus on 2050 is another arbitrary horizon. Conveniently, beyond 2050, the easy option treating the symptom rather than the cause via tree planting, will have a much lower effect. 

Large-scale forestry should not make windfall gains via the ETS at pastoral agriculture’s expense as such forest sinks are not a permanent solution. The extent of largely irreversible land use change from sheep and beef to forestry required to be effective is dramatic, as would be the impact on downstream industry and the regions generally.

One of the strengths of Upton’s report is its pulling together of a number of interrelated issues. Land use change affects both carbon emissions and water quality. Farmers should be incentivised to plant low-productivity areas in either plantation or permanent forest. 

The Ministry of Primary Industries’ ETS consultation documents are not encouraging in this respect. 

MPI sensibly proposes to simplify the ETS by moving to an average forest carbon accumulation without the contingent liabilities at harvest or via natural disaster. 

However, for the 80% of existing post-1989 forests MPI estimates are not registered, proposed transition arrangements mean they will not accrue any carbon credits for this or any subsequent rotation, yet there is no penalty for not replanting. 

The extent of the land use change necessary for forestry to temporarily meet GWP100 targets would be devastating for rural communities and the economics of residual livestock processing.

The ICCC openly contemplates stranded on-farm and processing assets. 

Widespread plantation forestry is a biological risk in itself and harvesting poses a huge risk of sediment discharges, of which recent east coast North Island events are just an extreme example.

While farmers are being encouraged to plant riparian strips, plantation forestry refuses to consider realistic set-backs from waterways, which has contributed to these sediment discharges.

There is also a suggestion that turpene emissions from pine trees might inhibit methane removal from the atmosphere.

Aside from the imperative to eliminate fossil fuels the greatest opportunity for warming mitigation is a reduction of short-term gases. 

Reduction of biological methane beyond 10% over 30 years would exceed the Paris Accord goal. Agriculture should be encouraged and rewarded if it can achieve that and be regarded as climate heroes not villains.

Carbon footprint and productivity gains of about 1% a year over the last 30 years suggest it might be achievable and thus provide NZ a sustainable warming reduction, particularly considering it is generally accepted we are at or close to peak cow. 

A similar strategy applies to nitrous oxide, the next most important short-lived gas. Farm system and forage changes plus fertiliser technologies should see reductions in both warming and nitrogen losses to the environment.

Following the holistic approach of the PCE report, the Government, if it genuinely wants a sustainable NZ solution consistent with the Paris accord should: 

 Plan to eliminate fossil fuels by 2050-2075 with a phase-out that allows adaptation and some purchase of international units;

 Treat short-term gases, methane in particular, separately to leverage the effects of their reductions;

 Set minimum reductions for short-term gases, perhaps via a separate methane ETS, likely to be reductions of the order of 10-20%;

 Incentivise appropriate reductions in short term gases as the best way to sustainably meet or exceed our Paris accord obligations. This is likely to be NZ’s lowest-cost, least-disruptive and most-likely-to-succeed strategy. Biological emitters should be rewarded for exceeding targets;

 Prioritise investment in science to achieve methane reduction with minimal production compromise;

 Encourage via the ETS more diverse tree planting, particularly on-farm and eliminate disincentives such as the proposed transition to forest averaging;

 Provide that tree planting on-farm can be used to directly offset farm emissions;

 Ensure incentives to satisfy Paris accord obligations via plantation forestry do not lead to large-scale land use change because they will at best provide short-term relief and pose risks;

 Require all plantation forestry, agriculture and horticulture to meet equivalent water quality standards. Nitrogen cycle technologies will be important in achieving this;

 Avoid easy-to-apply processor taxes that do nothing to encourage change in on-farm behaviour and;

 Not apply capital gains tax to inter-generational farming because it looks beyond short-term profitability to long-term sustainability.

Who am I?

Graeme Edwards is a Northland dairy farmer.

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