Victor Luca, 8-Aug-20.
Published, The Beacon 30-Sep-20.
This will be the forth post I will have written on Climate Change since I returned home to Whakatāne in early 2019. In the one dated 20-Sep-19 I pointed out that we in little old New Zealand represent only a tiny fraction of global emissions; less than about 0.2 % to put a number on it. My answer to the question of what we can do to avert an impending global climate disaster was to set an example in the hope of inducing major emitters such as China, the United States and Europe to follow suit. This is not a moral argument as some National politicians have cynically suggested in the past. Rather, it is a purely self-serving one. Having said that, our per-capita emissions do rank quite high and so morals are not totally irrelevant either.
The crux of my argument was that if we in NZ can’t get our own house in order, and in so doing induce major emitters to reduce emissions by setting an example, we are all done for. Our government seems to want to do the right thing, or at least be seen to be doing the right thing. In that regard, in November of 2019 our parliament passed the so-called ‘Zero Carbon Bill’. Conveniently left out of the bill however, were biogenic methane (CH4) emissions. Methane is a potent green-house gas (GHG) that is usually considered to be somewhere between 22 and 30 times more potent than CO2, although it only lasts about 12 years in the atmosphere.
Now it is time to take a close look at what we can actually do about this impending crisis/catastrophe that goes beyond posturing and platitudes.
If saving the planet boils down to reducing emissions, then we need to take a closer objective look at these emissions. In Figure 1a is a pie graph of NZ’s GHG emissions and it shows what most of us may already probably know, that agriculture is our biggest source of emissions accounting for about 49% of the pie. Energy production is the next largest slice of the pie at 39%. About 44% of this 39% is due to the transport sector (Figure 1b).
We could relatively easily cut transport sector emissions in half through all-out adoption of battery electric vehicles (BEV), a technology that I can confidently say has come of age. Everyone has heard of Tesla’s impressive BEVs but how about the Lucid Air that is expected to be available in early 2021. It can do 0-100 km/h in less than 2.8 seconds and has a maximum range of 855 km in mild weather.
Figure 1. (a) New Zealand’s GHG emissions by sector in 2013, (b) breakdown of energy sector emissions. Source: Mason, Transitioning New Zealand to Renewable Energy. EEA Conference & Exhibition 2017. IPPU is industrial emissions from product manufacture and use.
I reckon that with the way the technology is advancing the days of the internal combustion engine are numbered.
Despite the impressive specs of such ‘green’ vehicles we can never totally eliminate all GHG from the transport sector because the very process of building BEV’s generates GHGs and those emissions have to be taken into account. Comprehensive Life Cycle Analysis (LCA) studies have consistently shown that at best we can reduce transport emissions 50% if we fully embrace BEV technology. It would be better to reduce transport-related emissions to zero but we should take whatever we can get for now.
However, if we are truly wanting to reduce emissions we can’t simply ignore the biggest slice of the pie, which in our country, is due to intensive agriculture. We are not just feeding ourselves but much of Asia and other places.
A large proportion of agricultural emissions come from the livestock industry. Livestock emissions are from cow burps, and to a less extent farts, although other activities both within and outside the farm gate also count. There are about two cows for every person in New Zealand and five times more sheep than people. Despite the jokes Australians make about us Kiwis, they are not far behind in the sheep-per-capita numbers. It is often argued that the CH4 emitted by cows came from carbon in the grass eaten by cows which came from the CO2 in the atmosphere. However, this is a very simplistic argument since one needs to take into account the potency and lifetimes of these gases.
Cow burbs however only account for a part of craddle-to-farm gate emissions. There are plenty of other emissions to account for since this industry requires transport, refrigeration, fertilizer and so forth. These will all be accounted for in the life-cycle analysis.
Cows and sheep are called ruminant animals because they digest grass (carbohydrates) in the first chamber of their stomachs known as the rumen. In the rumen, carbohydrates (sugars) are broken down by fermentation with the main byproduct being methane which is produced in process called methanogenesis. But not all livestock use this digestive process that emits large quantities of methane. Next to each animal in the figure below I provide the Global Warming Potential (GWP) in Kg of CO2-eq emitted per Kg of meat produced (Kg CO2-eq/Kg). You can see that our steadfast friends, the cow and the sheep, have the highest GWP of all animals followed closely by the underrated drought-tolerant goat. On the next tier of the diagram appears first our friend the pig with a lower GWP by almost a factor of 10 compared to cows. Not far behind are kangaroos & wallabies. These animals are much despised in NZ but more loved in Australia. In fact, together with rabbits, kangaroos and wallabies are considered serious pests here (see Beacon article of 7-Aug-20). Then come the flightless birds including the turkey, ducks and chickens, which are highly favored sources of protein in countries such as the United States and France respectively. We of course eat our fair share of chicken in this country but not so much turkey and duck.
Figure 2. Global Warming Potential in Kg CO2-eq/Kg of different livestock. Source: Clunes et al. (2017).
Aside from GHG emissions, we should also consider the water requirements of these animals. Water is a precious resource and that needs to be taken into account. Again cows and sheep rank worst of all. It takes more than 15,400 L of water to produce 1 Kg of beef. Since the average cow weighs about 450 Kg and contains about 275 Kg of meat, that makes 4.2 million liters of water per cow. Sheep meat requires 30% less water and chicken meat about 60% less.
The conclusions here are inescapable. If we are really serious about the environment and reducing emissions then we simply cannot ignore the contribution livestock make to emissions. Perhaps it is time the planet started a gradual transition toward more climate friendly foods.
I have been aware of the risks posed by anthropogenic climate change for the better part of three decades and so far I have seen scant action - in fact we have been all talk and no action. In the past decade science has moved beyond talk of preventing climate change and more toward talk of adaption. This is clearly very bad news indeed.
More recently, I take heart from the fact that one of the main recent emitters, China, appears to be grabbing the bull by the horns. Aside from concerted efforts to electrify their entire transport sector, in 2016 Chinese authorities released new dietary guidelines recommending a 50% reduction in personal meat consumption by 2030. Incidentally, China is a country ruled by technocrats not bullshit artists and I suspect that whatever they do is in the interests of self-preservation.
Efforts are underway to reduce the amount of methane cows emit by genetic engineering and dietary manipulation and these are good avenues to pursue no matter what. However, at best reductions by these methods will be relatively marginal. Also, there is a limit on how much we can actually genetically engineer a cow. We have already done enough to this once formidable beast. To be realistic we will always want to drink cow’s milk and cheese so I guess we will never totally get rid of our friend the cow that has contributed to our country’s prosperity over decades.
But we could reduce our reliance on them and move to eating animals (if we are to eat animals at all) that are more consistent with the wellbeing of the planet and humanity.
We could place more emphasis on other sectors such as technology. So let’s put aside the bullshit and start adapting or risk perishing.
Another measure we could take is to eat more beans rather than beef. It has been shown that switching beef for beans in the United States could free up 42% of cropland (Harwatt et al., 2017). The cropland that is freed up could then be used to plant trees and this would help to remove CO2 from the atmosphere.
References
Harwatt et al., Substituting beans for beef as a contribution toward US climate change targets. Climate Change 2017, 143, 261.
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