Saturday, March 30, 2024

Farmers fight emissions in dark

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Using genetic modification to combat climate change emissions must be considered because existing mitigation measures have only limited impact, former Prime Minister’s chief science adviser Sir Peter Gluckman says.
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And there are questions about farmers’ ability to implement the measures available he says in a report on meeting New Zealand’s climate targets that also questions the use of Overseer for policing farm emissions.

Long-term climate stabilisation to avoid the most severe consequences of climate change requires very intensive and more urgent effort to reduce CO2 emissions to net zero or below while constraining emissions of other greenhouse gases, he said.

“NZ’s most important contribution to this effort will be in effectively reducing biological emissions from agriculture – an area where we are positioned to be world-leading. 

“Driving emissions mitigations from the agricultural sector is thus critical to the Government’s commitment to act domestically against climate change. 

“But the equation is not simple – it will involve trade-offs between multiple imperatives affecting different stakeholders differently.

“There are actions that farmers can take now and they should be encouraged to do so. 

“Many current approaches can be implemented to make small gains but there is much to be done to determine the optimal combinations for specific farm situations.”

Novel and effective ways to cut agricultural emissions show considerable, theoretical promise but many of the technologies will rely on gene editing or transgenic and genetic modification methods. 

That means there are important regulatory and social licence issues that will need to be considered as well as progress towards establishing context-specific proof of concept for reducing emissions.

The areas of greatest theoretical potential include transgenic forages such as AgResearch’s high energy ryegrass now being tested in United States field trials, transgenic endophytes and GM or GE forestry.

However, though the ryegrass has potential for considerable emissions reductions of more than 20% the inability to test such technologies in NZ conditions might be to the country’s long-term disadvantage.

“Each of these approaches would need broad social licence before any context-specific research was possible so these remain speculative approaches. 

“It is noteworthy that many ruminants in Europe now routinely consume GM feeds. 

“Clearly social licence for these technologies does not exist in NZ. However, given the progression of science on one hand and a broader understanding of the crisis of climate change on the other, not having a further discussion of these technologies at some point may limit our options.”

Various efforts are producing promising but limited answers and many questions remain, Gluckman said.

“Although some mitigation strategies based on existing technologies can be implemented immediately, their potential to significantly impact NZ’s emissions profile is not certain and will depend on complex biophysical, environmental and social interactions that need to be better understood in the context of individual farms. 

“NZ farms are highly variable in terms of landscape, land use, soil characteristics, tree cover, forages, livestock mix and farm management systems. Livestock farms are particularly complex systems with multiple, interacting components and determining the best approaches to reduce GHG emissions will depend on the specific local conditions and objectives of each individual farm.”

Modelling commissioned by the Biological Emissions Reference Group suggests available farm management practices might be able to reduce absolute biological emissions from individual farms in the range of 2% to 10%, possibly without reducing profitability although questions remain about the skills of farmers to achieve such outcomes. 

“However, it is important to note that many of the mitigation approaches are interconnected and are not necessarily additive – some combinations cannot be used together, others may improve reductions only incrementally when combined and in some cases reductions of one gas may result in increased emissions of other gases – referred to as pollution swapping.”

Farmers need to make strategic and responsive decisions about the many potential mitigation options so require decision-support tools that reflect actual reductions and that are linked to fiscal drivers. 

That is central to NZ’s climate change mitigation efforts in being able to measure progress from farm to national scale toward emissions reduction and demonstrably fulfilling international obligations.

“Unfortunately, there is no reliable way to directly and accurately measure emissions from an individual farm.

Overseer is the dominant tool used for accounting for GHG emissions, especially in the dairy sector, but is less suitable for complex farming systems involving mixed production. 

It was designed as a fertiliser use tool but is used by some regional councils as a regulatory tool in an effort to estimate and limit nutrient losses from farms. 

It is also used as a decision support tool to show the effect of changes in fertiliser use, effluent management and other farm management practices on nutrient losses affecting freshwater quality but even here its differential use between councils has proved controversial.

It was adapted to estimate on-farm emissions but there can be significant variability between the calculated and actual outputs. 

Though it can be used to identify practices that reduce emissions it can be difficult for farmers to use and does not account for all available mitigation options. Nor does it consider costs or economic outputs and cannot provide a full picture to support farmers’ decision-making.

The problem is compounded by the absence of a system-wide, accredited, advisory mechanism to help farmers make the best decisions both for the environment and the profitability of their farms) in a way that links their decisions to gas emissions abatement. 

“Many farm advisers at present will not have and cannot be expected to have the knowledge base to be effective in this regard,” Gluckman said.

And farmers need clear information to understand costs and benefits. That might best be served by a cadre of specialist advisers developing whole-farm environment plans that can accommodate the variable and economic needs of individual farms while considering the need to minimise GHG production in the context of all other initiatives.

“Failure to take action in the agricultural sector will not only be costly to those farmers who find themselves unprepared for change, it will also ultimately be costly to NZ,” Gluckman said.

MORE:

Read the report: http://www.pmcsa.org.nz/wp-content/uploads/Mitigating-agricultural-GHG-emissions-Strategies-for-meeting-NZs-goals.pdf

What’s next?

The Biological Emissions Reference Group is releasing the findings from research it has commissioned later this year.

Its report will include findings on various topics including:

• What mitigations can be implemented on-farm now and in the future;

• What the potential is for land-use change as a mitigation measure for climate change and its potential implications;

• What drives farmer decision-making in relation to climate change and;

• The costs and barriers of possible policy options to reduce biological emissions from agriculture including options for pricing biological emissions from agriculture via the Emissions Trading Scheme.

The Interim Climate Change Committee is doing a separate process to determine how agriculture can be included in the ETS.

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