Mike Cranstone, Whanganui Federated Farmers: Carbon Zero by 2050?

Two different futures for Whanganui hill country; we need to challenge the assumptions of what is best for the climate, the environment and our regional economy. Photo / Mike Cranstone

With the frantic pace that this Government wants to transition our country to a Zero Carbon economy, should we step back a moment and make sure that the principles and science are robust?

There has been significant research into understanding the different greenhouse gases roles' in climate change, how the biogenic carbon cycle works in a biological system such as agriculture and different stocks of carbon in the environment.
Unfortunately, many of our politicians and bureaucrats are blinkered by what we knew in the 1990s.

In November, the Primary Industries of New Zealand Summit was held at Te Papa. Over the two days of this conference, there were some insights into some of the research from this country's top scientists.

Professor David Frame, director of the NZ Climate Change Research Institute at Victoria University, exposed the fallacy of allowing companies to offset their fossil fuel emissions by planting trees. The plantation of trees will only sequester carbon from the atmosphere until it reaches maturity, for pine trees at about 40 years. At this point it is a saturated sink, whereas the CO2 from the burnt fossil fuel will continue warming the planet for 1000 years. The plantation of trees will help the country reach net zero emissions, but to stay at that level we will need to plant another plantation to offset the next 40 years of warming from that original CO2 emission. We will rapidly run out of productive land in New Zealand, in the process we will decimate the pastoral agricultural industry which not only is the economic glue of our provincial economies but earns $8 billion of export revenue.

Another interesting presentation was Dr Paul Mudge from Landcare Research titled Quantifying NZ's Soil Carbon Stocks. There is twice as much carbon in the soil as there is in the atmosphere. NZ's soils are high in carbon, typically at least twice the levels of the United States, South Africa and Australia. Ireland's with significant areas of peat land are higher.

Soil carbon is not accounted for in this country's carbon inventory, because it is difficult to measure and fluctuates with soil moisture. Landcare measures soil carbon at 500 sites across NZ and has measured 20-year trends under different land uses. Soil under grassland pasture averages 106 tonnes of carbon per hectare, with annual cropping this reduces by 16.2 tonnes and with exotic forest it reduces by 13.7 tonnes.

Is it fair or right to ignore part of the natural carbon cycle just because it is difficult to measure, so it is hard to place a monetary value on it? Agriculture is liable for the methane belched from livestock, but it receives no credit for the carbon removed from the atmosphere by photosynthesis or sequestered in the soil.

How we measure and account for our country's greenhouse gas emissions is set by the United Nations led IPCC. There are many flaws as to how emissions are accounted for; emissions are accounted for on a production basis rather than consumption, international offsetting is allowed utilising poorer countries' land resource to offset the emissions from the lifestyles of wealthy economies. In the Paris Accord the exclusion of emissions from air travel is a classic example. There is little motivation to change the rules when wealthy economies can maintain headroom for future warming while restricting the opportunities of agriculture dependent countries, being most developing nations along with our country.

We have some politicians who have staked their reputations on transitioning New Zealand to being Carbon Zero by 2050 or earlier. Their egos will reap the benefit, but the process to achieve it will deny future generations of New Zealanders of prosperity and opportunities. They are prepared to use agricultural land on which to plant trees to provide a 40-year band aid; it will look good on the greenhouse gas accounting ledger because of the current flawed rules, but once they are harvested or reach maturity, they will provide no further benefit to the planet's climate. Future generations of New Zealanders will be denied the opportunity of benefiting from this land, whether it be farming it themselves or from benefiting from the money that it brings into the country and our regional communities.