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Separating greenhouse gases in climate policy -Experts React

Press Release – Science Media Centre

The Parliamentary Commissioner for the Environment (PCE) has proposed the Government treat agricultural greenhouse gases differently to fossil fuel emissions in climate policy.

The Parliamentary Commissioner for the Environment (PCE) has proposed the Government treat agricultural greenhouse gases differently to fossil fuel emissions in climate policy.

In his report, Simon Upton suggests we should shift away from treating all greenhouse gas sources and sinks as interchangeable. Instead, he argues, we should use forest sinks to counter biological emissions and focus on reducing fossil-fuel derived CO2 emissions as soon as possible.

The SMC asked experts to comment on the PCE’s report.

Dr Sara Mikaloff-Fletcher, Atmospheric Scientist, NIWA comments:

“The PCE report lays out a pathway to a low carbon economy that focuses on eliminating fossil fuel emissions at the source, rather than offsetting them with carbon credits. Forest carbon uptake currently offsets nearly 30 per cent of New Zealand’s gross emissions, including fossil fuels, agriculture, and land use change. Yet, forests exist on different timescales than fossil fuel emissions. Carbon dioxide emitted to the atmosphere from fossil fuel burning remains there for hundreds of years, while carbon dioxide absorbed by a forest can be released on by logging, disease, forest fires, or climate change itself.

“The PCE report recommends two targets: 1) eliminating gross emissions from fossil fuels and 2) reducing net biological emissions (agriculture, land use change, etc.), which are combined under a single umbrella. Forest carbon uptake could only be used to offset agricultural emissions because the lifetime of these gases is relatively short.

“This is a bold approach, which focuses policy attention on eliminating fossil emissions of carbon dioxide, because they are the primary driver of climate change. Without this focus, we have no hope of achieving the goals of the Paris Agreement. By grouping biological sources and forest carbon credits under a single umbrella, the recommended strategy makes full use of the potential of our forests to slow climate change while reflecting the real limitations of over-reliance on forest carbon in the long term. This grouping may also give land managers flexibility to develop sustainable land use plans with multiple benefits.”

No conflict of interest.

Professor Ralph Sims, Director, Centre for Energy Research, Massey University, comments:

“The PCE’s report presents a good overview: like the rest of the world we have to concentrate on reducing carbon dioxide emissions eventually down to zero. Growing more forests can buy us some time by helping to offset emissions of greenhouse gases but is only a temporary measure. Competition for land use is a key issue to consider and planting trees must not be an excuse for delaying the transition away from burning coal, oil and natural gas (and deforestation) from where the carbon dioxide arises.

“In simple terms, as they grow trees absorb carbon dioxide during photosynthesis and thus lock up the carbon atoms in the woody biomass produced, thus removing carbon from the atmosphere. A hectare of land under pasture contains maybe 10-20 tonnes of carbon in the plants and soil. If planted in Pinus radiata, when the forest reaches maturity it will contain around 150-200 tonnes of carbon. But once the forest is harvested, or through a forest fire, much of this carbon will be released back into the atmosphere over time. If replanted, the carbon will be re-accumulated over time as the forest matures. One hectare of indigenous forest contains a ‘stock’ of around 300 tonnes of carbon that remains fairly constant as trees die and others grow to replace them. In its natural state, it has a carbon balance and so is not a forest sink.

“Planting one billion trees will need a land area roughly the same as the current 1.3 M ha of Pinus radiate (~5% of New Zealand’s total land area). This will include fencing off some areas of erosion-prone land unsuitable for farming, and letting it revert back to natural bush. Other marginal land with low productivity could be taken out of agricultural production by planting a range of tree species (including mānuka or other natives). Agro-forestry (grazing beneath widely spaced trees; riparian strips and shelterbelts) may also be planted. However, for the carbon content to be valued, it has to be measurable and that is only practically possible for larger plots. (But planting more trees in the garden all helps.)

“The PCE’s report concentrates on biological greenhouse gas emissions and the international dilemma of how best to compare the warming impact of different greenhouse gases. Growing trees absorb carbon dioxide, so how can that be used to offset methane produced when our sheep, cows and deer digest their food, especially since a molecule of methane survives in the atmosphere for only one or two decades, whereas a molecule of carbon dioxide survives for one or more centuries and thus the atmospheric concentration level accumulates more over time.

“Commendably, the report also looks at the wider picture as a ‘systems approach’ to the issue, including costs, impacts on communities, other environmental challenges etc. and correctly portrays the complexity of the climate problem and possible solutions that New Zealand could take based on our specific situation as principally a primary production economy. Should the recommendation be accepted by Government that forest sinks should only be used to offset biological emissions, then the voluntary investments in forests by Air New Zealand, Z Energy and other companies to offset their fossil fuel use will not be possible and urgently reducing their carbon dioxide emissions will be the only option.”

Conflict of interest statement: No conflicts (I own shares in a forest but it is outside of ETS).

Dr David Whitehead, plant and soil scientist, Manaaki Whenua – Landcare Research and New Zealand Agricultural Greenhouse Gas Research Centre, comments:

“There is no doubt that New Zealand needs to commit to more stringent actions to meet expected international obligations to reduce its greenhouse gas emissions. While New Zealand contributes very little to these global emissions, we need to develop technologies for our land-based economy to maintain credibility and make them available to other countries where they can be adopted more widely.

“This report addresses these issues with the fresh perspective of how we can change land use at large spatial scales larger than on individual farms. Such changes could also transform our farming systems to increase resilience to adverse climate events and improve community wellbeing. The overall benefit to enhancing other ecosystem services is much more than reducing greenhouse emissions.

“Treating biological and fossil emissions separately is a very sensible approach. Forestry expansion remains a predominant way to offset emissions but the report clearly identifies the long-term risks. Opportunities and willingness to introduce more diverse farming systems at landscape scales, incorporating trees, need to be encouraged, involving less intensive land use, fewer animals and reduced water and fertiliser inputs. The report addresses the conundrum of increasing soil carbon stocks and, sensibly, concludes that there is yet insufficient certainty from scientific studies to support inclusion of changes in soil carbon to meet emissions reduction targets.

“There is enormous opportunity to increase soil carbon in degraded landscapes globally with additional benefits to food security. The focus for New Zealand must be to prioritise land management practices that prevent further reductions in soil carbon stocks and increase resilience of our agricultural systems.”

Conflict of interest statement: I receive funding to undertake research in mitigating greenhouse gas emissions but I have no conflicts of interest.

Catherine Leining, Policy Fellow, Motu Economic and Public Policy Research, comments:

“The Parliamentary Commissioner for the Environment usefully reinforces three important points: targets and policies should reflect differences across greenhouse gases, fossil carbon dioxide (CO2) emissions need to reach zero during this century, and management of New Zealand’s land sector would be enhanced by a landscape approach that integrates climate change and other considerations.

“The PCE’s proposed solution is to create separate emissions trading systems (ETS) for fossil and biological emissions. The fossil system does not appear to include non-energy industrial emissions; the report suggests these may not be price responsive and could benefit from ongoing free allocation or auction revenue recycling. The logic for this is not clear given CO2 needs to go to zero and some fossil fuel uses will also be difficult to replace. The report signals landfill emissions could potentially join the biological trading system.

“If New Zealand was starting to design mitigation policy with a blank slate, the proposed two-system approach could be a valid choice. However, the same concerns raised by the PCE can also be addressed within a single all-sectors, all-gases ETS using the readily available toolkit of greenhouse gas metrics, forestry rules, free allocation, and application of additional standards, regulations and policies to drive sector-specific change. Whether using a one-system or two-system approach, it is possible to achieve different marginal emission prices and emission outcomes for different sectors. Under a single system, if progress with reducing fossil CO2 emissions seems too slow, the cap can be tightened and fossil fuel standards, regulations and policies strengthened to accelerate progress. If forest sequestration or biological emissions seem too high, forestry rules, GHG metrics or agricultural free allocation could be adjusted.

“New Zealand’s government, businesses and foresters are already heavily invested in a single ETS. Experience suggests policy volatility can be harder to manage – and more important for long-term investment – than price volatility. The September 2017 election marked the first time ever that New Zealand had carbon pricing policy continuity across a change in government. In this context, adjusting the existing ETS wisely and rapidly with cross-party support could do a lot more for domestic decarbonisation than engineering a complicated transition to a new and uncertain set of policies.”

These comments are provided in my individual capacity. No conflict of interest.

Dr Robyn Dynes, Farm Systems Scientist, AgResearch, comments:

“The report challenges policymakers and landowners to learn from previous land use transformations. Rural communities already live with the impact of previous broad brush interventions which led to transformations of the landscape, and understand both the positive and negative outcomes of these changes. These communities must be at the table to bring their voice to policy development. The report case study from the Hurunui catchment demonstrates the scale of the benefits to the agricultural sector of this proposal and of the opportunities our sectors must take to inform policy.

“This alternate approach for New Zealand provides the opportunity for landowners, their catchment and community to be in the driving seat to shape how their catchment will transform in land use over time. It also offers the opportunity for all we know about land and environmental process to come together, which can be shaped by the grassroots knowledge of the farming sector and communities. The incentive could be there for those who live in these communities to bring their collective innovation to find ways to more than balance sources and sinks, and to address other values in their solutions. With this alternative approach, areas of forestry would still increase, driven by landowners seeking to rebalance the natural capital on which they depend and within the wider ecosystems services which they already value.”

Conflict of interest statement: Robyn Dynes provided science information for the preparation of this report.

She also received funding from MPI for research into GHG emissions.

Dr Ivan Diaz-Rainey, Associate Professor of Finance and Co-Director of the Otago Energy Research Centre, comments:

“The elephant in the room of New Zealand climate policy for some time has been what to do with biological emissions from agriculture. The New Zealand Emissions Trading Scheme (NZ ETS) was meant to be an all gasses and all sectors scheme, but that never materialised with agriculture ‘given a free ride’ in the decade or so since the NZ ETS’ inception.

“This report begins to map the way forward both for biological emissions and the role that forestry sinks play in meeting New Zealand’s international climate commitments. Chapter 4 provides an alternative vision to the all gasses and all sectors flexibility envisioned for the original New Zealand Emissions Trading Scheme. It suggests differentiating carbon and biological emissions since the former are long-lived and the latter are relatively short-lived.

“Further, it suggests afforestation carbon sinks should only be used to offset biological emissions – the logic being that using afforestation to tackle carbon reductions creates risks since forest may burn down, eventually they will need harvesting and ultimately land in which to plant them is limited and may crowd-out other land uses. Using afforestation to tackle our carbon reductions means that we do not work hard enough to decarbonise the economy in more fundamental ways (switching to electric vehicles; building passive houses etc.).

“Overall the report signals a fundamentally different approach to climate policy than that envisioned with the NZ ETS over a decade ago. Differentiating carbon and biological emissions is sensible both from a science and a political expediency perspective. Reducing reliance on carbon sinks also seem very sensible (there will still be afforestation but just not as much).

“If the government does go down this path it will represent major changes for the NZ ETS. It will become more of a NZ Carbon Trading Scheme and the ‘cheap’ afforestation option will be gone.

“Does this mean a free ride for agriculture once more? Probably not, but the devil will be in the detail. The agricultural sector are heavy energy users so they will be covered by the inevitable rise in mitigation costs implied by the changes outlined above.

“What the reduction targets for biological emissions should be is not clear – though the reports cites a range of between 22–48% by 2050 as potentially feasible with investment in R&D (p.119). Nor is the mechanisms of achieving any such target yet apparent; it could be a separate biological emissions trading scheme or a levy.

“The degree to which afforestation can be used to offset agricultural emissions also needs to be thought about; should this be unlimited? Might unlimited offsets lead to landscapes that are either forests or relatively intensive dairy farming, with little else in between? Clearly, there needs to be strong incentives to reduce biological emissions beyond the offset option that push towards more sustainable forms of farming.”

No conflicts of interest.

Professor Euan Mason, School of Forestry, University of Canterbury, comments:

“Forests tend to be short-term sinks, on scales of up to centuries, but eventually they simply become reservoirs. So they can help us reach a target such as net-zero greenhouse gases by 2050, but eventually we need to reduce emissions and we should not divert ourselves from that goal.

“The PCE’s premise that forests are short term reservoirs, however, is open to debate. Forests in aggregate are often maintained over millennia, and the question of what average level of carbon storage they represent can be predicted quite accurately. The implication of this weak premise is that forests could, if we chose, be used to provide long-term storage of carbon that was previously placed in the atmosphere by burning of fossil fuels. Trees represent the most economically viable mechanism for removing CO2 from the atmosphere, and we ignore this potential at our peril.

“If we follow his recommendations we would inevitably have to abandon our commitment to greenhouse gas neutrality by 2050. The Globe report makes it abundantly clear that we cannot get there by 2050 without integrating tree sequestration into our overall plan.

“Separating land-based emissions and sequestration from transport and industrial emissions policy has one benefit and some clear disadvantages. The obvious benefit is that our ‘cap and trade’ emissions trading scheme would finally become logical without forestry. A cap could be set, and no tree-planting loophole would be available to allow people to exceed the cap.

“The main disadvantage is that agriculture would once again be given a free pass, and in a sense, the forestry sector would be made responsible for cleaning up agriculture’s messes.

“From an international perspective, New Zealand would still be polluting the atmosphere with methane and nitrous oxide, while claiming that our carbon dioxide sequestration was off-setting those gaseous emissions. We’d still be faced with the prospect of comparing greenhouse effects of CO2 with those of methane and nitrous oxide, while ignoring the obvious and easy balance between CO2 sequestration and CO2 emissions.

“On balance, I welcome the report, but I see it as a valuable contribution to the debate rather than as an obvious solution.”

No conflict of interest.

Professor Dave Frame, NZ Climate Change Research Institute, Victoria University of Wellington, comments:

“This report is a thoughtful and constructive look at New Zealand’s land sector and how it contributes to climate change. It’s a far more comprehensive view of the sector’s contribution than has been assembled before.

“Its perspective that the roles of various emissions sources and sinks should be thought about in terms of how they contribute to warming is very welcome, and I think very constructive. As with the Productivity Commission’s work last year, there’s an active acknowledgement of the important differences between gases which accumulate (like CO2) and those which do not (like methane).

“The report applies similar thinking about timescales and permanence to forestry sinks. This is a good idea, and a necessary step if we are to develop a coherent, warming-focused set of climate policies across all sectors. I think it’s a really valuable resource.”

I have no conflicts of interest here.

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