Want to save the world this Christmas? The best way may not be what you think... and may not involve giving up meat

It's the time of year many start thinking about their diet, about turning over a new leaf. An the Paris climate talks may have given that new impetus for those keen to 'save the planet'. But it's abstinence – meaning eating and travelling less – that they should be considering, rather than a new diet or production system.

This is a poorly timed message – given the current commitment to over-indulging during the holiday season – is nevertheless an important consideration this New Year.

And it's not just about food. In New Zealand, the most common birthday between 1980 and 2014 was 30th September; 40 weeks after Christmas. That suggests a fertile holiday period. In the USA it is 16th September, indicating Christmas conception.

The Worldometer Population Clock is indicating a world population of almost 7.4 billion people and 140 million births already this year. New Zealand is not overpopulated, and arguments have been put forward (e.g. by the New Zealand Institute of Economic Research) that 15 million would give a more stable and innovative economy. However, every individual contributes to the global challenges through consumption of food, goods and transport (directly and indirectly), creating greenhouse gases (GHG) and waste. And the world is heading towards more people than it can sustain.

The Paris talks were accompanied by comments about vegetarian diets or veganism being potential saviours of the planet. These were followed in short order by a report from Carnegie Mellon University researchers with headlines that lettuce created more GHG than bacon and that vegetarians were actually creating more harm than their meat-eating counterparts. Claims that organic systems should replace conventional systems for better outcomes were also made.

The reality, as it so often does, depends on starting point, relativity and alternatives.

A vegetarian diet in theory avoids killing things (the realist might point out that the harvesting of grain crops tends to result in the death of insects and rodents). It does usually include eggs and dairy products. Purists would say that an egg has to die in order to be eaten, and they might also avoid cheese because the rennet involved in making cheese used to come from dead calves. (The latter is no longer true – most cheese involves rennet created through advances in biotechnology, specifically genetic engineering (GE). Although the GE micro-organisms involved in rennet are killed after fermentation, so that no GE components are in the ultimate product [e.g., cheese], the process does involve genetic engineering of DNA from bovines into yeast – trans-genics.)

Replacing pasture with crops reduces the organic matter in the soil (in New Zealand the pasture figure is approximately 8.5% whereas the cropping figure is approximately 5%) and increases the requirement for cultivation, irrigation, nutrients (fertilisers) to replace harvested material and chemical control of weeds and pests. This in turn increases GHG through loss of organic matter, fuel and the embodied GHG in chemical creation.

And it's important to remember that ideal cropping land is limited in area; using land that's not ideal increases the environmental impact (e.g., through erosion and/or nutrient loss), increases the requirement for intervention (fertilisers and other chemicals) and is generally associated with lower yields. Headlines such as ‘give up meat to save the planet’ tend to overlook the difficulties of producing protein for human consumption without involving animals to harvest grass from non-ideal areas.

Another factor in what makes any stretch of land ‘ideal’ is climate and distance to market. New Zealand is limited to fava beans in the protein crops it can grow successfully (though more hot dry weather on the Canterbury Plains, such as that currently being experienced, could increase the potential for lentils, soya beans and chickpeas). Nutritional websites indicate that one hundred grams of dry fava beans contains approximately 8g protein in comparison with 26g protein for red meat. The Foundation for Arable Research, however, records a protein concentration of approximately 27% and yields of 8.5 t/ha, giving 1.7 t/ha of protein.

DairyNZ data suggests this can be compared with milk protein of approximately 600 kg/ha. Fava beans appear to produce more protein, but there is an ongoing debate about the quality of plant versus animal protein for human consumption. The GHG comparison then depends on the amount of fuel and chemical to harvest the protein and to render it in edible form.

Vegan diets eschew all animal protein and animal products (leather belts, shoes and bags, for instance, plus anything containing gelatine such as ‘lollies’ and marshmallows, or L-cysteine such as some peanut brands, bagels and breads). Earlier this year ‘Going vegan could save the world, reports UN study’ appeared on various websites. The articles went on to say: ‘According to a new UN report, “A global shift towards a vegan diet is vital to save the world from hunger, fuel poverty, and the worst impacts of climate change”.

The report, Assessing the environmental impacts of consumption and production: priority products and materials was actually published in 2010 and the only place ‘diet’ was mentioned, apart from once in the reference list, was in the future outlook section 6.62:

“impacts from agriculture are expected to increase substantially due to population growth, increasing consumption of animal products. Unlike fossil fuels, it is difficult to look for alternatives: people have to eat. A substantial reduction of impacts would be possible with a substantial worldwide diet change, away from animal products.”

Veganism was not mentioned in the original report, and a ‘substantial shift’ clearly requires a starting point, relativity and consideration of alternatives. Writing in the Lancet in 2007, authors McMichael, Powles, Butler and Uauy from The Australian National University proposed 90g of meat a day as a working global target, with not more than 50g coming from ruminants. World Economic Forum data indicate that average meat consumption per day in the USA and Australia is 250g; the New Zealand average is 200g and China is 134g.

A ‘move away’ from animal products can be achieved without becoming vegan, leaving animals to graze pastures (thereby maintaining soil organic matter) where cropping is not possible. It's also worth considering that animals on poorer quality pasture (on poorer quality land) do not produce as much milk or meat as those on high quality pasture (and land), which means an increase in GHG per unit of production – it is the same argument as that used for crops.

Meat and milk are produced for fewer GHG per unit of production from pasture-fed than grain-fed animals, putting New Zealand in a very good position for premium markets. (A poll by Peparami in the UK reported that men would rather give up sex, booze, Sky Sports and their jobs, and swim with sharks, than become vegetarian.)

The headline indicating that ‘eating lettuce is more than three times worse in GHG emission than eating bacon’ is a further example of misrepresentation. Bacon does not appear in the original paper, and the calculation was GHG per calorie. It is well known that lettuce is a super-model food…

Another popular ‘save the world’ suggestion is changing from conventional to organic systems which are believed not to require chemicals. The reality is that without ‘intervention’, yields would be severely compromised and ‘natural’ chemicals are allowed. Copper sulphate and lime sulphur are permitted in organic production systems in New Zealand to control fungi such as brown spot or mildew, and neem, derris and pyrethrins are permitted for use against insects.

Organic production systems do not mean pesticide or chemical free, but the limited range of chemicals that are allowed means that control of pests is not generally as effective in comparison with conventional systems.

AgResearch has shown that organic sheep and beef farms tend to be operating at 60% of the production of conventional farms; Lincoln, Otago and Massey Universities have shown that organic dairy farms operate at 70-80% and horticulture is somewhere between 0 and 100% depending on the season and pest and disease pressure.

Of further consideration is that results of a meta-analysis of research comparing organic and conventional systems done by researchers at Oxford and Cambridge Universities have indicated that although organic farming practices generally had positive impacts on the environment per unit of area, the same was not necessarily true per unit of production. Because of lower yields in organic systems, the effect of GHG per unit of production (meat or milk) was higher from organic than conventional systems.

These comparisons were done in developed countries where efficiencies of production are high; relativities must be remembered…. Where yields are low because fertilisers and chemicals are not available, organic systems involving ‘natural’ additions can improve yields.

There are no simple solutions; not in population, diet or production system. Even ‘moderation in all things’ has detractors because a widely diverse diet (tempting the palate) has been associated with a wider waistline by researchers at The University of Texas, Houston.

The fundamental problem for the world is the ever-increasing number of people, doing an ever increasing amount of travel and expecting to have more and more things from all over the world – food as well as ‘stuff’.

Nothing an individual chooses to do will have a direct impact, but a move to ‘cutting back’ could, with encouragement, go viral. Cutting back, however, must always consider the starting point, the relativities and the alternatives.

The New Year is a great time to resolve to do better, whatever that means for you.