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The Great Carbon Myth. 3 March 2021

The Great Carbon Myth. 3 March 2021

Forests have always played a critical part of our environment as carbon sinks, consuming about a quarter of the carbon dioxide pollution produced worldwide.

But decades of warming temperatures and drought have increased wildfire risks which in turn have the potential to change forests from carbon sinks to carbon sources.

There is currently, an increasing amount of interest in understanding how to recognise and encourage carbon sequestration on farmland.

To do this effectively, an accurate and comprehensive estimate of net emissions and removals from vegetation and soils on farmland is required.

Studies have shown that grass pastures can store more carbon than forests because they are impacted less by droughts and wildfires and this doesn’t include the potential benefits of good land management to help boost soil health and increase carbon stocks in grass pastures.

Forests have always played a critical part of our environment as carbon sinks, consuming about a quarter of the carbon dioxide pollution produced worldwide.

But decades of warming temperatures and drought have increased wildfire risks which in turn have the potential to change forests from carbon sinks to carbon sources.

Increased drought and wildfire risk make grass pasture more reliable as carbon sinks than trees.

Unlike forests, grass pastures sequester most of their carbon underground, while forests store it mostly in woody biomass and leaves. When wildfires cause trees to go up in flames, the burned carbon they formerly stored is released back to the atmosphere. When fire burns grass pastures, however, the carbon fixed underground tends to stay in the roots and soil.

In a stable climate, trees store more carbon than grass pastures. But with global warming and a drought-likely future, we could lose some of the most productive carbon sinks on the planet from the extreme weather changes that are beginning to occur all over the world.

A recent report prepared by Auckland University of Technology, estimated woody vegetation on sheep and beef farms may be offsetting 63 to 118 per cent of the gross agricultural emissions from this sector (Case and Ryan, 2020).

In contrast, the findings of the recent report prepared by the Ministry for the Environment indicated net carbon dioxide removals are 63 per cent lower than the midpoint estimate of the Auckland University of Technology report by Case and Ryan (2020), equivalent to 33 per cent of the on-farm agricultural emissions.

This MfE report claims to provide a robust and up-to-date estimate of net carbon dioxide removals occurring on sheep and beef farmland.

I am not suggesting that grass pastures should replace forests on the landscape or diminish the many other benefits of trees.

Trees and forests are an ecological necessity but when you put them into the Emissions Trading Scheme assuming they’re carbon sinks and trading them for pollution credits (ETS) while they’re not behaving as carbon sinks, emissions may not decrease as much as we hope.”

The carbon sequestration from farming is currently ignored under the ETS and surely this must mean that the basis for analysis of the GHG emissions from farming is based on flawed science and therefore gives an incorrect measure of the actual emissions from farming.

This then means that farming is unfairly penalised under the ETS from the omission of farming’s carbon sequestration ability, particularly given that the predictions are that we will see significant increase in global warming in the near future and the effects (from drought and wildfires) that this may have in relation to forestry.

We lose many hectares of farmland each year, much of which becomes greenhouse-gas-emitting housing developments, shopping centres, roads and parking lots. But the remaining millions of hectares of farmlands nationwide represent significant additional carbon storage with at least 33% the farming emissions being offset (which is currently ignored in the ETS even though MfE has recognised this offsetting in their current report).

When people look at farming they think of greenhouse gas emissions yet farming systems are actually sequestering carbon, yet the carbon sequestration is totally ignored when discussing emissions from farming.

It is only fair that if the discussions are to be held around the detrimental effects of farming on the environment, then the beneficial effects should also be part of the discussion to reflect the reality of the situation and bring some much needed balance to the discussions.

The world needs agriculture in all its different forms to ensure the population can be fed so any discussion should be based on science and include all of the relevant information that gives a realistic starting point when discussing rules around agriculture.

Unlike the current situation where the beneficial effects of agriculture have been totally removed from the discussion and there is no balance.

The failure to include the beneficial effects, (from carbon sequestration through to security of food supply) highlights the inequity in the current discussions where agriculture is being unfairly portrayed as a destroyer of the natural environment, when in actual fact it is no worse or better than other parts of society as we see it today. 

Farming is currently being asked to lower its carbon footprint to comply with New Zealand’s Paris agreement requirements when in fact if the true picture is used which includes the total carbon sequestration from all forms of on farm vegetation, then the farming industry will be seen to be nowhere near as bad as it has been portrayed in discussions up to now and this is supported by the findings of this report.

Even taking into account just the minimum offsetting figure produced in the MfE report of 33%, the farming industry in New Zealand has definitely been poorly served by government, in the whole discussion around GHG’s and farming’s part in New Zealand’s emission levels.

When we then take into account the differences between short lived GHG’s (Methane) & long lived GHG’s (Carbon Dioxide) and recognise that farming mainly produces methane, we can see even more clearly how poorly the farming industry has been treated by government through their total ignorance of the offsetting from on farm vegetation.

The “Great Carbon Myth” is that farming is the main cause of our GHG emissions and also that it will be the cure-all for those emissions. The current requirements on farming in relation to GHG emissions will only have the effect of endangering our country’s economy, our farmer’s economic survival and security of our food supply.

Andy Loader.

Co-Chairman P.L.U.G.