Thursday, April 25, 2024

New report raises serious questions about NZ’s methane targets: Feds

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Federated Farmers say the Climate Change Commission to take this significant new research into account and set targets based on a climate warming approach. 
Federated Farmers, Beef + Lamb and DairyNZ heads Wayne Langford, Kate Acland and Jim van der Poel after their meeting in Hamilton, Friday 15 September 2023. Photo: Stephen Barker / Barker Photography. ©Federated Farmers of NZ
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For years Federated Farmers have argued that New Zealand’s methane reduction targets go further and faster than is fair for Kiwi farmers.  A new scientific report from the Universities of Oxford and Cranfield has confirmed we were probably right. 

There are now serious questions being asked about the ambition and scientific underpinning of our current methane reduction targets. 

The report, commissioned by Federated Farmers, DairyNZ and Beef + Lamb NZ, found that if other countries meet their existing emissions reduction commitments then a 15% reduction in methane would see New Zealand methane contribute no additional warming from 2020 – and warming is the problem. That’s why the Paris Agreement has a temperature target.

“The current methane reduction targets have been a real point of contention for most farmers who have felt like they’ve been asked to go further and faster than needed – that’s why this new study is so important,” Federated Farmers President Wayne Langford says. 

“For years farmers have been told that we’re responsible for half of New Zealand’s emissions, but this report clearly shows that we’re not responsible for half of the warming – and global warming is what we’re trying to prevent.”

The Zero Carbon Act targets require reductions of 10% by 2030 and 24-47% by 2050 relative to 2017 levels, but the global understanding of climate change science has evolved significantly since New Zealand set those targets in 2019. 

With the Climate Change Commission (CCC) set to review New Zealand’s methane reduction targets in 2024 in line with Zero Carbon Act, Federated Farmers, B+LNZ, and DairyNZ commissioned research to help inform the conversation and help work out the most appropriate way agriculture can contribute to New Zealand’s climate goals.  We want the Commission to take this significant new research into account and set targets based on a climate warming approach. 

The study on the warming impact of New Zealand’s current methane targets was led by internationally respected climate scientist Professor Myles Allen.  He’s a Professor of Geosystem Science at the University of Oxford, Director of the Oxford Net Zero Initiative, and has been described by the BBC as ‘the physicist behind net zero’. Fellow Oxford experts Jessica Zionts and Miyabi Barth, and Dr Michelle Cain of Cranfield University also contributed to the research. These are highly credible international climate scientists who are widely regarded as experts when it comes to methane.
The study found that if other countries meet their existing emissions reduction commitments, then a 15% reduction in methane would see emissions of that gas from New Zealand contribute not additional warming from 2020 levels.  If countries significantly increased their current levels of ambition, a reduction of up to 27% of methane in New Zealand may be required.

Or to frame that in another way, the study found that if we stick to current methane reduction targets, that will offset all the additional warming from carbon dioxide and nitrous oxide from the entire New Zealand economy. This raises serious equity issues for rural communities and farming families who may be asked to shoulder more than their fair share of the climate burden to offset a lack of emissions reductions in urban communities. 

Essentially the current targets would see New Zealand peak its warming in the 2030s and reverse back to 2022-27 levels which is well ahead of most other countries who are currently aiming to achieve peak warming (“net zero”) from 2050. 

The research is a critical contribution to the conversation about climate change and raises serious equity concerns for farmers who may be being asked to do more of the heavy lifting, and bear more of the cost, than other parts of the economy.

That’s an even more pertinent question when one considers that agriculture delivers more than 60% of New Zealand’s merchandise exports.

Federated Farmers will continue to advocate that warming impact of the various greenhouse gases is the key consideration in any debate on reduction targets.  Together with B+LNZ and DairyNZ, Wayne Landford says Feds aim is to continue to inform farmers and New Zealand communities about warming impacts ahead of the Climate Change Commission’s public consultation in 2024.
Farmers will then have the opportunity to have their say on the Commission’s advice on targets in 2024.

“Farmers have been making huge progress in reducing our environmental footprint and our methane emissions have been stable or declining for the last decade,” Langford said.

“If we want to get an accurate picture of how we are progressing as part of global efforts, it’s important that we measure and report our emissions based on their warming impact. Total emissions just don’t give you the full picture”.

These tables, from the Universities of Oxford and Cranfield report, show the differences between the contribution to warming by methane and carbon dioxide under various emissions scenarios.

Why is it important to take a warming approach?

• The Paris Agreement’s goal is to limit warming to well below 2 degrees.  It therefore makes sense that a country’s climate change objectives take account of how much they are contributing to warming.

• Most countries globally are aiming to be “net zero” by 2050. For countries that have emissions profiles dominated by CO2, this means that they will cease contributing to further warming (achieving peak warming) by approximately 2050. 

• For CO2 emissions to cause no additional warming, they need to be reduced to net-zero. 

• Methane emissions do not need to be reduced to zero to stop causing additional warming.  

• Under the current methane targets New Zealand would achieve peak warming in the 2030s and reverse warming back to 2022-2027 levels by 2050. This is because the “cooling” impact of the ambitious reductions in agriculture (and waste) offset the ongoing additional warming caused by energy and transport over this period. 

• Methane, a short-lived gas, does not accumulate in the atmosphere in the same way as long-lived gases like CO2 and N2O. While more potent than CO2 at trapping heat in the atmosphere, methane persists in the atmosphere for around 12 years as opposed to the millennial timescale of CO2. 

Why did the Government set targets of 24-47% 

• The Government recognized that methane is different and does not need to go to zero by taking a split gas approach in the Zero Carbon Bill. 

• It took the 24-47% reduction targets from an IPCC “special report on pathways to 1.5 degrees” that came out in 2019, but the authors of that report specifically said that the ranges in their report should not be used as national targets and countries should determine their own relevant ones.  

• Professor Myles Allen was a coordinating lead author of the IPCC report

A word on greenhouse gas metrics

In 1997, the Kyoto Protocol standardised national emissions reporting by applying the Global Warming Potential (GWP) accounting metric and applying a 100-year time horizon so greenhouse gases could be combined into a single common unit. However, there have been concerns as to the accuracy of GWP100 for decades, and that it has created distorting incentives. 

Professor Myles Allen and fellow report authors say this is because the amount of global warming caused by short-lived GHGs is largely driven by their annual emissions rate (i.e., the flow into the atmosphere of that gas). This contrasts with long-lived GHGs such as CO2, as their contribution to global warming is dependent on the total cumulative emissions since pre-industrialisation (i.e. the stock of the gas in the atmosphere).    

GWP* is a ‘flow-based’ metric, which looks at the rate-of-change of short-lived GHG emissions, which contrasts with GWP and GTP which are both ‘stock-based’. Given the Paris Agreement’s goal to limit warming to well below 2 degrees, the authors note that using a metric that measures the contribution of each gas to warming relative to that threshold would constitute a useful policy tool that more accurately represented progress towards the temperature target. 

While countries are required to use GWP100 for international reporting of their emissions and NDCs (nationally determined commitments), there is nothing to prevent them from also using other metrics as a basis for their emissions reduction policies. Allen and his team argue it could also be useful for countries to report GHGs separately and set separate targets alongside their GWP conversions. 

“This would allow tracking of an entity’s contribution to warming in addition to progress towards targets set using aggregate stock-based metrics.”

NZ agriculture is not the greatest contributor to warming

Professor Allen and his fellow researchers state that in New Zealand prior to 1990, methane was the dominant contributor to global warming, causing nearly 60% of New Zealand’s contribution to global warming since 1850.  While there has been a lot of discussion about historic warming and responsibility to reduce, their report notes that most developed countries have opposed this. 

“Countries with CO2 as their predominant gas could only remove their historic warming by actively removing CO2 from the atmosphere, and can only stop adding to additional warming by reaching net zero. As such, contributions to additional warming since 1990, arguably the earliest date of an emerging international consensus on the climate issue, are generally considered more relevant,” their summary report states. 

The report therefore assessed the relative contribution of each gas to warming since 1990 and found that energy had contributed the largest proportion (54%) and agriculture second at 37%.  Methane was responsible for just 16% and nitrous oxide 20% of the 37% contribution to warming from agriculture over this period. 

The Oxford study showed that methane’s contribution to ongoing warming has reduced significantly, particularly in the last decade, because methane emissions have been stable or declining. The authors noted that, while agriculture was 51% of current annual emissions using GWP100, this was quite different to its current contribution to warming and this reinforced the importance of taking a warming approach to emissions.

Federated Farmers, New Zealand’s leading independent rural advocacy organisation, has established a news and insights partnership with AgriHQ, the country’s leading rural publisher, to give the farmers of New Zealand a more informed, united and stronger voice. Feds news and commentary appears each week in its own section of the Farmers Weekly print edition and online.

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