DELTA Model version 1.3 launched

NickS on 4 May 2021

The coloured bar shows the global average availability of each nutrient. The error bars show the range in availability in different parts of the world (10th and 90th population percentiles based on country level averages). While there are only a couple of nutrients where global availability is below target, the level of variation results in many more nutrients of concern at a country level.

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The latest version of the DELTA Model is now available online. It features new insights into national and regional nutrient availability, as well as nutrient trade.

It’s common to talk about food trade between countries or regions, but less common to think about the movement of individual food nutrients around the world. For example, New Zealanders are probably very aware of our country’s exports of animal-sourced foods (like dairy and red meat), but likely haven’t thought about what this means in terms of the calcium or iron included in these exports.

DELTA 1.3 presents the domestic production of 29 food nutrients, the export and import dynamics of these nutrients, and how this measures up to meeting per capita per day nutrient targets for a country. It also presents how this availability differs in different parts of the world, showing the user the inequalities in access to different nutrients. The results are adjusted for waste, non-food uses and bioavailability in the same way as the rest of the DELTA calculations.

Another change is to the splash page first displayed to the user. This now features an outline of the global nutrition challenge that the world is facing, as well as a description of how the DELTA Model was designed to contribute to our understanding of this complex challenge. Further additions and changes can be found in the release notes.

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Bottom trawling dragging up more than just fish

NickS on 20 April 2021

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A recent paper in Nature includes evidence that bottom trawling releases more CO2 emissions from carbon stores in marine sediment than the entire aviation industry.

Similar to how our soils store carbon, our oceans stock the largest amount of carbon on the planet. The paper suggests a framework to prioritise protection areas of the ocean that would see multiple benefits. These include preserving biodiversity, increasing yield for fisheries and securing marine carbon stocks.

Marine sediment stores carbon, which is released during bottom trawling, a common practise of fisheries. According to the present study, this activity was estimated to release 1 gigaton of carbon every year. Comparatively, the aviation industry releases about 918 million tonnes. However, all is not doom and gloom, as the paper also identifies areas that would be most beneficial to protect. They calculated 90% of the carbon disturbance could be avoided through protecting only 4% of the ocean, although this comes at a cost of 27 million tonnes of fish. Level of benefit in biodiversity, carbon and food are illustrated in various conservation strategies, dependent on the value placed on these factors.

This is not to say we should all rush to the airport, nor does this suggest forgoing fish and chip Friday. Rather, our ever-expanding database on the impact of human activities is a reminder of the system view we must take when exploring what a ‘sustainable’ lifestyle may look like. The global food system is full of intricacies, and the impact some food products have on the world could far surpass what seems reasonable.

As our breadth of knowledge from these individual studies increase, as do our capabilities in modelling and drawing evidence-based insights on our global food system. By also suggesting beneficial protection areas, rather than exclusively focusing on the impacts of bottom trawling, this paper may spark conversation rather than accusation between the fisheries industry and marine conservation groups.

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Could regenerative agriculture offer a solution to a more sustainable food system?

NickS on 13 April 2021

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Regenerative agriculture is a hot topic after suggestions it offers a partial remedy to climate change. However, for a concept surrounded with such high expectation, there is very little clarity around the definition of regenerative agriculture or it’s evidence-based benefits. The National Science Challenge, Our Land and Water New Zealand have published a white paper calling for further clarity and scientific testing of claims.

The term regenerative agriculture identifies an approach to food and farming systems that originated in the US focusing on five farming principles that claim to regenerate the land, rather than degrade it as many conventional practices have been found to do. These principles are: minimise soil disruption, keep soils covered, plant diverse crops, reduce fertiliser use, and practise rotational grazing. This idea has been embraced by the general public, leaving agricultural sectors around the world challenged to apply it to their own unique systems.

In our hunger for a quick fix to climate change, many have jumped on the assumption that regenerative agriculture could be a farmer’s way out of the flack often received for agriculture’s impacts on the environment. However, this may be an overly optimistic stance to a challenge that far exceeds the implementation of a regenerative mindset.

The white paper comes from over 200 representatives of the New Zealand agriculture sector to determine the next steps for regenerative agriculture research. Some of the recommendations include:

  • There is a requirement for further evidence-based research and trials on the true benefits, both environmental and economic, of regenerative agriculture for the farmer and food producers by assessing marketability and export value.
  • Application of the term ‘regenerative agriculture’ differs between countries. Although the term was conceived in the US, the mindset can be applied to other countries as long as it is made relevant, i.e. bringing in cultural aspects and maximising what the land may already have – for New Zealand this can be focusing on retaining soil carbon levels while the US looks at increasing soil carbon.

If food and farming is to be truly regenerative then a framework based on validated science is required. In the meantime, perhaps the concept of regenerative agriculture can act as a reminder to farmers and consumers of the care and consideration our environment deserves.

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The life of your food: A discussion of LCAs

NickS on 1 April 2021

A low impact lifestyle has become desirable as the consequences of our excessive consumption are exposed. However, how do we assess the environmental impacts that our product choices have? Here, we discuss the use of life cycle analyses (LCAs) and the challenges and opportunities these pose in estimating the environmental impact of our food systems.

LCAs are an assessment method used to estimate the environmental impact of items over their lifetime. Such impacts can include water use, land use and greenhouse gas emissions (GHGs). When used correctly, they can be an effective comparative tool between similar items and highlight points in the value chain for improvement.

LCAs have a number of stages, and there are a range of types of LCA. Lifecycle inventories (LCIs) are first collected, which take account of all inputs and outputs within a system. This is followed by LCIAs (lifecycle impact assessment) where the impacts of LCIs are quantified and often differentiated into ecosystem impacts, human impacts and resource depletion. The commonly used term ‘footprint’ can represent a partial or full LCA, but only focuses on one aspect of the system. For example, a water footprint assesses the impact on water availability and quality across the entire life cycle of the product, but this would not include the impact on carbon emissions or land use.

LCAs are recognised as a useful impact assessment tool and as such have standardised methods set by ISO (International Organization for Standardisation). These guidelines have been interpreted differently throughout the literature, especially when applied to a system requiring the allocation of upstream products and inputs that serve in more than one system. For example, water used to irrigate rice paddies would form part of the water footprint of the rice. However, if the rice straw is also used as animal feed, how should the water footprint be allocated between the rice and animal production? Another issue with the methodology when applied to GHGs is that it typically only uses the GWP100 climate change metric, which can misinterpret short lived gas potentials e.g. methane. These limitations highlight the complexities of LCAs and the need for consistent methodology to improve the reliability of the assessment.

Using LCAs for the estimate of a product’s impact provides a landscape where the products can be compared. Although this can see misinterpretation, which will be discussed later, the complexities of this process can also offer up informative results for consumers and producers that may not seem obvious at first glance. This can be best used when comparing products that are similar in their final output (i.e. provide an equivalent user benefit), but may differ in their production chain e.g. competitor products, items produced in different regions and countries, or comparing similar products manufactured by the same company.

One product may have a variety of impact levels dependent on its origin, where it was purchased, right down to the practices of the individual farmer. Simple consumer choices may significantly decrease an individual’s impact. When choosing a discretionary food like chocolate, the choice of dark chocolate over milk or white chocolate significantly reduces the environmental impact. A difference in the nutritional composition of these products should be noted, although it is not a product we eat for its nutritional benefit. Furthermore, it has also been found using LCAs that a change to using 100% recyclables will result in minor reductions in an individual’s carbon footprint, and rather a focus on simply reducing consumption of packaging would see better results.

One of the most robust uses of LCAs is in the optimisation of company production lines. An internal LCA can pinpoint both the area with the most opportunity to reduce impact (e.g. manufacture, shipping, retail) or highlight one product having less impact than another, signifying its value for the company. Having numerical figures produced by LCAs can also provide tangible options for tracking improvements through regular analyses. For example, following its first LCA in 2009, Nespresso committed to reducing the carbon footprint of a cup of its coffee by 28% by 2020. Through these LCAs, Nespresso also investigated the impact between coffee systems to show the use of Nespresso was equal in carbon footprint with three other common coffee systems, while fully automated coffee systems had the highest carbon footprint. Not only does the direct product hold opportunity for more sustainable consumption choices; so too do the processes used to extract the coffee.

The benefits of the accurate use and awareness of LCAs go further than educating individuals or companies. As the literature on LCAs increases across a broader range of products, processes and end-of-life options, it allows consumers to make informed decisions in their quest for a truly low impact life. This also provides critical data to modelling platforms such as the DELTA Model.

With the complexities of LCAs comes the opportunity for misleading comparisons. This can be through comparing two products that have little similarity in characteristics, comparing different parts of the value chain (cradle-to-farmgate versus cradle-to-grave), or only using one footprint to pull conclusions on an item’s entire impact. These have led to some misconceptions, especially when inappropriately exploited by commercial interests to promote one product over another. For example, plant-based milks being touted by some as better for the environment than dairy.

The environmental impact of bovine milk has shown significant variation between different countries, right down to differences inter-regionally. This variation allows the impact assessment outputs to be picked in favour of marketing claims by competitors. When used to compare bovine milk to plant-based alternatives, LCAs can create oversimplified and misinterpreted conclusions such as assuming nutritional equivalence between products, or using global average impacts not representative of the variation between production systems. More appropriate use of LCAs in milk comparisons would be to compare plant-based milks with one another, or compare different farming systems and practises between countries.

This scenario exemplifies the potential misuse of the tool, and highlights a gap in the literature that LCAs are yet to fill when applied to delivery of nutrition. A focus has been placed on whole products and macronutrients, where LCAs give footprints per kg of product or, less commonly, per kg of protein. Micronutrients are yet to be explored and would be an instrumental addition when considering the entire impact of food. This has become even more critical as deficiencies in specific nutrients when feeding the global population have been suggested by the DELTA Model. This gap can be demonstrated in LCA comparisons of protein sources that claim protein powders are more efficient protein sources than cheeses, grains and beef when considering their environmental impacts. This study does not include the numerous micronutrients also received from the ‘less efficient’ protein sources.

Taking a holistic view, you could argue that given the interconnectivity of complex systems such as the food system, even seemingly unrelated factors can have indirect impacts on one another. LCAs can provide an excellent measurement tool when estimating the impact of products on individual environmental factors. However, the examples of misinterpretation and the opportunity for further research demonstrate how the application of LCAs can fall victim to tunnel vision when estimating a product’s true impact. This absence of a holistic view can produce results misleading for consumers. Narrow LCAs provide one piece of the puzzle and consideration should be made of the broader impacts the product has on our planet, our bank accounts, our health and our livelihoods.

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Plight of the bumblebee

NickS on 16 March 2021

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Research in Global Change Biology has shown that cultivated land dependent on pollinators has increased by 137% over the last 50 years. Simultaneously, monoculture cropping has also increased, leaving pollinators challenged for diverse food sources at all times of the year.

Concerns over the decreasing population of many insect pollinators, particularly bees, are broadly heard. While many agricultural crops provide a food source for these insects, their seasonality means that they cannot be their sole food source. Expansion of monoculture agriculture leads to a decreasing diversity of available food sources for pollinators.

The article looks at global and regional trends, finding substantial differences in the degree of dependence on pollinators around the world. Generally, the greatest dependence on pollinators for successful cropping was in developing nations.

The article recommends the use of marginal land for pollinator-friendly plants and farmland heterogeneity, as conserving pollinator populations is essential to ongoing agricultural productivity.

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Perspectives on buying local

NickS on 9 March 2021

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A discussion piece for the Sustainable Food Trust addresses whether the movement towards buying locally sourced food in developed nations is an appropriate behaviour for all, particularly lower income families.

The two main sides to this debate are that, while local food systems may have social advantages and keep the economic benefits of food production within the community, such activity is often expensive and not available to all. The article addresses to what extent either argument is true, and how widely repeated statements on food and nutrition may not reflect the true experiences of the majority of people.

The author ends with the need to understand the evidential basis of different points of view on local food, a conclusion that is applicable to the sustainable food system debate generally. Regarding the wisdom of buying local, there is no single answer. It is not always the case that locally produced food has a lower environmental footprint or better nutritional content than the alternatives, and this should not be assumed.

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Trading in soil carbon stocks

NickS on 4 March 2021

Soil carbon has become a hot topic, with carbon sequestration in soil a possible method for reducing atmospheric CO2. But this isn’t an easy task, and there’s a lot more to soil carbon than just sequestration. Here, we provide an overview of soil carbon flows and what they mean in the context of the global food system.

The term soil carbon refers to carbon stocks, in various forms, present in the world’s soil. Soil carbon can be organic (e.g. living or decomposing organisms, humus) or inorganic (e.g. carbon-containing minerals such as calcite).

The amount of carbon in the world’s soils is estimated in the region of 2500 gigatons, more than three times that present in the atmosphere and more than four times that in all living organisms. Organic matter in the soil, including soil carbon, is vital to good soil health, improving water and nutrient retention, maintaining soil structure and as nutrient sources for plant and microbial life.

Soil carbon content can be understood as the balance between carbon inputs and carbon losses. A major contributor to soil carbon inputs is photosynthesis. Plants capture atmospheric CO2, which is transferred below the soil surface via the roots. As well as contributing to the structure of the plant, some carbon is passed to rhizobial microorganisms, the microbial populations that live in close association with plant roots. As root structures and microbial populations in the soil grow, so too does the bound soil carbon.

Carbon can also be added to the soil through decomposing plant and animal material. The process of decomposition involves microbial respiration, which releases CO2 into the atmosphere, but some of the carbon in the decomposing material remains in the soil. The net balance between carbon inputs and losses to the atmosphere determine whether the soil carbon concentration increases or decreases.

However, further complexity is added to the system by other, abiotic factors. Soil composition, temperature, water content and erosion all influence soil carbon cycling. Naturally, this means that soil carbon stocks vary enormously between different parts of the world, from less than 1 tonne of carbon per hectare in desert environments to several hundred tonnes in tropical forests. Even within local regions, soil type can result in significant differences in soil carbon concentrations. This variation makes quantifying soil carbon challenging.

Agriculture directly influences soil carbon stocks. Clearing of land for agriculture, and tillage and cropping are generally considered to reduce soil carbon concentrations. However, this is not always the case: in certain systems, conversion of forest to grassland results in increased soil carbon concentrations, but it is uncertain how permanent this change is.

A number of activities exist that can increase carbon sequestration in the soil, or decrease the rate of carbon loss incurred by agriculture. Reducing tillage and soil erosion minimises carbon loss to the atmosphere or to waterways, while organic fertiliser application can add to the carbon input on agricultural land. The use of cover crops, which prevent leaving the soil bare between cropping cycles, can also help to maintain or even increase soil organic carbon.

The benefits of such practices are both local and global. Increased soil carbon benefits soil health, increasing crop yields in some systems. The benefits to soil structure of high soil carbon also allow for better retention of micronutrients, such as iron and zinc. This can result in higher concentrations of these mineral in crops, and thus in our own nutrition.

However, there are challenges in increasing agricultural soil carbon stocks in many areas. It is far easier to add to soil carbon in areas where the current concentration is low than in areas with relatively high existing stocks, which may be close to saturation with carbon. Moreover, it is easier for agricultural interventions to increase carbon concentrations in the upper layers of soil than the deeper layers.

Perhaps the greatest driver of recent interest in soil carbon is for its potential in sequestering atmospheric carbon emissions from human activity. Atmospheric carbon, in the form of CO2, is well known as a greenhouse gas. Thus, the possibility of using soil as a carbon sink is gaining momentum.

The potential of this possibility has recently been demonstrated in Australia. Australia has an existing Carbon Farming Initiative that provides the legislation for obtaining carbon credits by demonstrating increases in soil carbon on owned land. Recently, an Australian cattle farm sold carbon credits to Microsoft to the value of $500,000, obtained entirely from soil carbon sequestration from the management of the farm’s grazing land.

Schemes like the Carbon Farming Initiative have the potential to spread. However, in order to quantify changes in soil carbon stocks, it is essential to measure changes in soil carbon over time. This can be done by taking soil samples from a number of representative sites and quantifying the carbon present. These measurements can then be repeated to establish changes in soil carbon concentration over time. However, the wide variation in soil carbon even within a small area makes generalisation of carbon concentrations difficult. Currently, work is underway to benchmark New Zealand soil carbon concentrations, with a view to tracking changes in the future. This work will have to contend with the difficulties of varied concentrations, but may ultimately lead to some form of soil carbon credit system in New Zealand.

Study of soil carbon is benefiting from the interest sparked by the need to reduce atmospheric carbon concentrations. However, its importance to the global food system reaches beyond carbon sequestration. Healthy soils play a role in reducing the environmental impacts of agriculture by retaining nutrients and structure, and enabling optimum crop yield and nutrient content. In the future, the drive for carbon sequestration may also influence land management and provide another source of income for food producers.

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Social perspectives on the future of livestock

NickS on 23 February 2021

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A recent article in Animal Frontiers identifies the social perspectives on the sustainability of animal-sourced food production, with a view to what this production might look like in the future.

The increasing global population and per capita income is predicted to drive food demand up by around 50%. But it is challenging to predict what role livestock will have in satisfying this demand.

As well as requiring increases in productivity with a reduced environmental footprint, animal-sourced food producers must maintain their “social license to operate” – the acceptance of their practices by consumers. General interest in how animal-sourced foods are produced is rising, and the author contextualises this discussion with some statistics for the US livestock industry.

From an environmental perspective, improvements are being made in reducing the amount of feed, land, water and greenhouse gas emissions of animal-sourced foods due to improved genetics, crop yields and management practices. US beef production reduced its land use footprint per kilo of beef by 33% between 1977 and 2007 and greenhouse gases by 16%. US pork production reduced its feed use per kilo of pork by 67% between 1959 and 2009, and water use by 22%. US milk production has reduced land use, fuel use and greenhouse gas emissions by around 20% each in just the ten years up to 2017.

There is also evidence that further improvements can be made, with wide differences in the footprints of animal-sourced food production even within the same country. Bringing the average closer to best practice should be as much a goal as pushing the boundaries of how small these footprints can become. These improvements must also be communicated to consumers.

The article identifies three key issues that should be prioritised by the animal-sourced food industry when considering its future: accounting for greenhouse gases equitably, with consideration of their differing lifespans; wider use of non-human-edible by-products as animal feed; and greater consideration of animal health and welfare. Each of these priorities will have benefits for the production, environmental sustainability and consumer perceptions of animal-sourced foods.

The author’s final thought is around demonstration and communication of the facts around animal-sourced food production, to ensure than consumer choices are evidence-based.

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WWF encourage planet-based diet

NickS on 9 February 2021

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The WWF report Bending the Curve: The Restorative Power of Planet-Based Diets joins other efforts to demonstrate the negative health and environmental consequences of our current way of producing and consuming food, while proposing ways to turn this around.

The report opens with the assertion that our food system must provide healthy, safe, affordable and nutritious diets for all, with reference to the UN Food Systems Summit later this year and the Sustainable Development Goals. This is completely in line with the principles of SNI: nutrition must come first when considering the global food system. The report then goes on to define planet-based diets as win-wins: healthy and with low environmental impacts and explores how these can be achieved.

A major recommendation of the report is that national dietary guidelines need to be more ambitious. This echoes a results of a previous WWF model. Currently, these guidelines largely reflect a healthier version of current consumption patterns and do not consider environmental impacts. The report argues that guidelines could be simultaneously healthier and more sustainable.

The main health recommendation of the report is to increase the plant-based proportion of the diet and decrease overconsumption. This is supported by the Global Burden of Disease study findings, indicating that low wholegrain and fruit intake, as well as high sodium intake, were the greatest dietary risk factors.

Beyond these overarching directions, recommendations for dietary and production change vary on a regional level. This is due to the difference in dietary, health and environmental factors seen in different parts of the world.

Countering biodiversity loss also requires a nuanced approach. For example, the report finds that most of the biodiversity loss associated with the Danish diet is due to imports of coffee, tea, cocoa and spices. Contrastingly, red meat holds this place for Latin American countries.

Similarly, the report states that we must feed our population on existing agricultural land and not further expand, but again the implications vary by region. Countries suffering from widespread undernutrition may need to expand their agricultural land to ensure healthy diets for their population, while more developed countries may need to contract.

The same regional variability is true for the planting of trees for carbon sequestration, conversion of grazing land to arable or optimising water use. The results of the report emphasise careful consideration of actions at a national level, as healthier diets can lead to increased environmental damage of one kind or another in vulnerable regions. A one-size-fits-all approach will not lead to a sustainable food system.

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FAO Statistical Yearbook 2020 shows big changes

NickS on 2 February 2021

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The latest global statistics from FAO show large increases in both crop and animal-sourced food production, but also reductions in cropland and agricultural employment.

Since 2000, there has been a drop of just over 1 billion people from the agriculture workforce, going from 40% of global employment to just 27% in recent years.

Countering this, use of agricultural pesticides increased sharply between 2000 and 2012, before levelling off. Increases were also seen for fertiliser, contributing to the 50% increase in crop production since 2000. Sugar cane, maize, wheat and rice dominate crop production, and the production of each is dominated by two or three countries.

The total agricultural land these crops are grown on showed reduction since 2000, decreasing by 75 million hectares, with a similar decrease of 89 million hectares of forest land.

In terms of animal-sourced foods, chicken showed the greatest increase of the meats, growing by 47% and reaching similar production quantities to pork, the highest producing meat sector. Milk production increased by 45%, while egg production increased by 50%.

Fisheries production showed a similar increase of 42% and is still dominated by marine fish. However, the expansion of aquaculture led to a 131% increase in freshwater fish since 2000. Aquaculture now represents 46% of total fisheries production, compared to 26% in 2000, with China largely responsible for the increase.

The increased food production coupled with decreased agricultural land and employment emphasise the increased efficiency, intensity and automation in food production. However, it should be noted that this is a global picture and that insights at a regional level are also necessary to fully understand the global food system.

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