What’s happening and what’s causing it?
Global warming is happening. This is fact. The main reason is the rapid increase of carbon dioxide, nitrous oxide and methane in the atmosphere. These ‘greenhouse’ gases (GHGs) trap heat which would otherwise be lost from the planet. See the graph of CO2 increase since 1960!
At least 80% of the increase is a direct result of activities and processes which would not be happening if the human race was not present on earth. Foremost among these is the mining and burning of fossil fuels, particularly to make electricity and fuel for manufacturing, heating, cooling and transport of all types, and the increase in agricultural production. The burning of coal is the single biggest producer of carbon dioxide. Rice paddies are the biggest producer of methane internationally, followed by cattle and sheep burps. The urine of cows is responsible for about half of New Zealand’s nitrous oxide emissions, probably the most potent GHG per gram, because of our large number of cows.
Some climate change deniers argue that because there is geological evidence that episodes of global warming occurred before humans were around, it cannot be true that we are the main cause this time. Others adopt the view that even if we are, why worry, because some natural global warming event will come along sooner or later anyway. For sure, any number of natural events may have caused both global warming and ice-ages in the past. Huge releases of molten magma and sunlight-blocking massive meteor hits are the odds-on favourites respectively. But this time round, it is beyond reasonable doubt that it is very largely due to the activities of Homo Sapiens. Only fully paid-up members of the Flat Earth Society think otherwise. These people cannot cope with the idea that Earth is not just a place for us to live on and do what we like, and that our actions all have reactions.
The man-made rise in global temperatures does not follow a straight line. There are ups and downs caused by short and longer-term climate effects. But the trend line is up, no question.
The rapid increase in the amount of the Artic ice-shelf that melts year-on-year is perhaps the best example. This cools the sea and air, which brings colder weather down to Europe in the winter. The same occurs in the Eastern United States. This is climate change, a sub-set of global warming. Some incredibly naïve people present these very cold winter events as ‘proof’ that there is no global warming.
Once the Artic does not ice up much over winter anymore, the rate of increase in temperature in the Northern Hemisphere will accelerate. This might just be uncontrollable. Greta Thunberg has every right to be very angry.
At this point in time, the main effect of overall global warming we see in the short term is increasing climate change. Colder air passing over warming seawater (and vice-versa) causes increasingly violent thermal interactions, leading to increasing numbers of increasingly violent storms, particularly in equatorial regions. These will just keep getting more and more violent and frequent. Rising sea-levels will greatly exacerbate the coastal damage caused by storms.
It is great that young people like Greta can galvanise youth to put increasing pressure on governments to take effective action. Without this, I think it is likely to take a few years of high-fatality summer heatwaves in Europe, North Africa, the United States and India before concerted and effective world action is taken. The question is, will it be too late by then? We can expect mass migration of climate refugees to the nearest cooler and wetter countries involving far greater numbers than those of civil war refugees from the Middle East and North Africa in recent years.
What should New Zealand do?
While it is true that New Zealand cannot by itself improve global warming by itself, we must not use this as an excuse to do nothing. We can lead by example by both doing the research to establish what we could do to greatly reduce our emissions, and equally importantly, put the findings of this research into effect with no delay.
So, what does all this mean for New Zealand agriculture? We all need to think this through carefully, not just hide behind the parts of the wider story that suit us. An increasing proportion on Kiwi’s know very little about farming life, and have little or no perception of how dependent all of us are dependent for our standard of living.
There is no doubt that the intensity of dairy farming in New Zealand needs to be reduced. In the last 20-25 years, we have progressively pushed the capacity of many of our soils, particularly the shallow irrigated ones, well beyond their ability to efficiently recycle the nutrient inputs as fertiliser and more recently as animal feeds like palm kernel extract (PKE). The overuse of the very inefficient granular fertiliser urea, soluble phosphate and PKE feed are the key mistakes that cause pollution of our waterways. The increasing number of cows per hectare this allows means more and more excreta and effluent that is being applied to the soil.
Dairy farmers need and deserve to be able to make a good living from grazed pastures, but this brings with it a few caveats. Bringing about much improved water quality and greatly reduced gaseous emissions are the most important. Fencing of waterways and the use of riparian strips and wetlands where practicable are an important start. Every bit as important are (i) increasing the percentage of clover and other forage plants in the pasture, (ii) the use of far less PKE, (iii) minimising the use of winter crops, and relying much more on farm-grown maize, hay and silage, (iv) limiting fertiliser N use to 100 kg N/ha of fertiliser annually, which will automatically drive the change to more efficient N fertiliser, (v) limiting soil Olsen P levels to 30% of the ASC (P Retention), and (vi) replacing soluble P fertiliser with sustained release forms. The last 3 actually reduce farm costs.
Why aren’t these mitigations happening much faster?
I think that the main reasons for the slow rate of adoption of many of the most cost-effective mitigations are (a) a lack of cohesion between government and industry interests, and (b) Fonterra’s auction system, combined with rushed and expensive pushes into difficult markets. This strategy has pushed their suppliers down the path of having to producing more and more milksolids to remain profitable. Under this sort of pressure, they are very hesitant to change their farming system. Those hundreds of millions of dollars wasted in China should have being put instead into creating a truly credible and premium NZ dairy brand, by giving farmers the tools and incentives they need to greatly reduce adverse environmental effects. Then and only then should we be looking at expanding overseas.
Unfortunately, new cost-effective tools to achieve true sustainability are damned with faint praise by those with vested interests. For example, instead of the regional councils demanding that the fertiliser industry develop and promote more environmentally- protective and cost-effective fertilisers, farmers are pressured to install expensive on-farm works like riparian strips. The big industry players play lip-service to it; it barely rates are mention in Ballance’s ‘Mitigator’ . The big Regional Councils such as WRC tow the line by ignoring the scientific evidence in favour of using more cost-effective and environmentally-protective N and P fertilisers.
While riparian strips do reduce bacterial run-off and sediment loss (except in storm events, when they can become sources of bacteria and sediment), they do very little to reduce total farm nitrate leaching, GHG emissions and P run-off and leaching. Fenced-off grass berms work just as well; in fact better long-term, because the grass can be harvested for silage. But the most effective mitigations are to use more efficient fertiliser N and sustained-release P. As for these over-hyped ‘phosphate walls’. Who will be paying to install and maintain these? Why, the farmer of course! If sustained-release P is used, they are totally unnecessary!
In the absence of these being supported by the big players, increasing regulation by Government is becoming inevitable. Overseer, in its current form at least, is definitely not the answer. It was developed in the first place to justify the increasing use of N and soluble P by the fertiliser industry. It greatly underestimates P run-off from soluble P vs sustained release P such as RPR. The ability to reduce ammonia volatilisation losses compared to granular urea by using ONEsystem nbpt-treated prilled urea are not mentioned, despite independently-conducted trials under on grazed dairy farms being published scientifically (NZ Grasslands Journal) 4 years ago. Ammonia is not a GHG directly, but it is the key component in the formation of very fine particulate smog that is so deadly to our lungs. Nitrate leaching and nitrous oxide GHG can be reduced with lower N-content pastures and by detecting and treating fresh patches with Spikey®.
The nutrient loss models in Overseer need to be either totally rebuilt by independent scientists. But there are very, very few of this breed in New Zealand. The great majority of AgResearch’s and Massey and Lincoln’s fertiliser research is channelled through the two big players.
Interlinkage of water quality and GHG emissions in NZ
Water quality and climate change are inextricably interlinked. Once we have far more specific and effective mitigations underway to improve our water quality and reduce GHG emissions, and doing a far more credible job of marketing our dairy products internationally, we need to be putting more resources into reducing methane emissions from livestock. The potential to achieve this is actually very high. The current level of emissions come about almost entirely because of the presence of methanogenic organisms (actually a group called archaea, not bacteria) in the rumen, that get rid of excess hydrogen released from the feed by turning it into methane. Bacteria on the other and have evolved ways to combine the hydrogen with carbon in far more energy-efficient ways.
There are at least a dozen quite-different, promising options for reducing the concentration of methanogenic organisms in the rumen. Some may even increase production by increasing feed utilisation. More digestible feeds are known to result in less methane being produced. Individual animals of a species can vary 4-fold in the amount of methane they produce. We need to learn a great deal more about selecting low methane-emitting cows, beef and sheep without penalising production.
In the meantime, dairy production in New Zealand needs to be reduced by 20%, provided the mitigations mentioned earlier are put into practice. Most of this reduction needs to be on the shallow, irrigated free-draining soils of Canterbury and in poorly drained – or mole and tile drained – soils elsewhere.
Emissions from transport
As far as GHG emissions from transport are concerned, I have always been sceptical about the true, net benefits of battery-powered electric vehicles, especially in countries where the electricity itself is derived from fossil fuel or natural gas plants. New Zealand has a big advantage in producing most of its electricity from hydro plants. But even in New Zealand’s case, there needs to be far more in-depth study of the ‘vehicle-life-cycle’ advantages in costs and emissions.
Recent studies in Europe have incorporated the increasingly complex design, manufacturing and recycling costs of battery-powered EVs, rather than looking just the reduction in their running costs and emissions. They have shown that EVs are definitely preferable to diesels, but have little or no life-cycle cost or emissions advantage over high-efficiency petrol or non-plug-in petrol-hybrid cars. And that is without considering what is going to be done environmentally with all the (non-recyclable) lithium batteries from EVs. Or consideration of what happens if a cartel is formed between the 2 or 3 countries that have virtually all the world’s lithium?
I believe that hydrogen fuel-cells (that make their own electricity on the go) will take over from battery EVs within 30 years, rendering battery EVs just as unloved as diesel-powered cars are rapidly becoming. The safe storage, distribution and handling of hydrogen still faces challenges, but these will be overcome. The required infrastructure costs will be huge. But range-anxiety will be gone, and cars fitted with 1000 km range fuel-cells will be even lighter than petrol-powered cars. And New Zealand simply has to find ways to greatly reduce the massive use of diesel for transporting goods by heavy trucks. Diesel typically makes up 25% of their total running costs. Hydrogen fuel cell -powered trucks are way ahead of any other option, I believe.
The big picture for New Zealand
If all the above are brought totally into effect over the next 30 years, New Zealand’s emissions will be less than half what they are now. Realistically, dairy production will not have to fall more than 20%. Once-a-day milking will become much more common. One of the many benefits this brings is the ease of tapping into regular 8 hours-a-day and even part-time labour from neighbouring towns.
Putting huge areas of New Zealand into forestry can destroy rural communities. Also, when a forest is harvested and exported 25-30 years after planting, we lose the carbon stored in them, and we spend the next 30 years building it up again. To achieving an ongoing increase in fixed carbon from exotic forestry we need to ensure that the timber is sold only for permanent use like housing. So New Zealand needs to be producing kitset homes for export, not selling logs to be made into short-life paper and cardboard overseas.
We must do what we can to directly reduce the emission of carbon dioxide and other GHGs. A tax on GHG production puts the cost where it needs to be, so society can assimilate its true environmental costs into life choices. By comparison, carbon exchange schemes muddy the water.