The link below is to an article that takes a look at increased home ranges of giraffes dues to the proximity of towns and reduced food sources.
If we’re serious about feeding the world’s growing population healthy food, and not ruining the planet, we need to get used to a new style of eating. This includes cutting our Western meat and sugar intakes by around 50%, and doubling the amount of nuts, fruits, vegetables and legumes we consume.
These are the findings our the EAT-Lancet Commission, released today. The Commission brought together 37 leading experts in nutrition, agriculture, ecology, political sciences and environmental sustainability, from 16 countries.
Over two years, we mapped the links between food, health and the environment and formulated global targets for healthy diets and sustainable food production. This includes five specific strategies to achieve them through global cooperation.
Right now, we produce, ship, eat and waste food in a way that is a lose-lose for both people and planet – but we can flip this trend.
What’s going wrong with our food supply?
Almost one billion people lack sufficient food, yet more than two billion suffer from obesity and food-related diseases such as diabetes and heart disease.
The foods causing these health epidemics – combined with the way we produce our food – are pushing our planet to the brink.
One-third of the greenhouse gas emissions that drive climate change come from food production. Our global food system leads to extensive deforestation and species extinction, while depleting our oceans, and fresh water resources.
To make matters worse, we lose or throw away around one-third of all food produced. That’s enough to feed the world’s hungry four times over, every year.
At the same time, our food systems are at risk due to environmental degradation and climate change. These food systems are essential to providing the diverse, high-quality foods we all consume every day.
A radical new approach
To improve the health of people and the planet, we’ve developed a “planetary health diet” which is globally applicable – irrespective of your geographic, economic or cultural background – and locally adaptable.
The diet is a “flexitarian” approach to eating. It’s largely composed of vegetables and fruits, wholegrains, legumes, nuts and unsaturated oils. It includes high-quality meat, dairy and sugar, but in quantities far lower than are consumed in many wealthier societies.
The planetary health diet consists of:
- vegetables and fruit (550g per day per day)
- wholegrains (230 grams per day)
- dairy products such as milk and cheese (250g per day)
- protein sourced from plants, such as lentils, peas, nuts and soy foods (100 grams per day)
- small quantities of fish (28 grams per day), chicken (25 grams per day) and red meat (14 grams per day)
- eggs (1.5 per week)
- small quantities of fats (50g per day) and sugar (30g per day).
Of course, some populations don’t get nearly enough animal-source foods necessary for growth, cognitive development and optimal nutrition. Food systems in these regions need to improve access to healthy, high-quality diets for all.
The shift is radical but achievable – and is possible without any expansion in land use for agriculture. Such a shift will also see us reduce the amount of water used during production, while reducing nitrogen and phosphorous usage and runoff. This is critical to safeguarding land and ocean resources.
By 2040, our food systems should begin soaking up greenhouse emissions – rather than being a net emitter. Carbon dioxide emissions must be down to zero, while methane and nitrous oxide emissions be kept in close check.
How to get there
The commission outlines five implementable strategies for a food transformation:
1. Make healthy diets the new normal – leaving no-one behind
Shift the world to healthy, tasty and sustainable diets by investing in better public health information and implementing supportive policies. Start with kids – much can happen by changing school meals to form healthy and sustainable habits, early on.
Unhealthy food outlets and their marketing must be restricted. Informal markets and street vendors should also be encouraged to sell healthier and more sustainable food.
2. Grow what’s best for both people and planet
Realign food system priorities for people and planet so agriculture becomes a leading contributor to sustainable development rather than the largest driver of environmental change. Examples include:
- incorporating organic farm waste into soils
- drastically reducing tillage where soil is turned and churned to prepare for growing crops
- investing more in agroforestry, where trees or shrubs are grown around or among crops or pastureland to increase biodiversity and reduce erosion
- producing a more diverse range of foods in circular farming systems that protect and enhance biodiversity, rather than farming single crops or livestock.
The measure of success in this area is that agriculture one day becomes a carbon sink, absorbing carbon dioxide from the atmosphere.
3. Produce more of the right food, from less
Move away from producing “more” food towards producing “better food”.
This means using sustainable “agroecological” practices and emerging technologies, such as applying micro doses of fertiliser via GPS-guided tractors, or improving drip irrigation and using drought-resistant food sources to get more “crop per drop” of water.
In animal production, reformulating feed to make it more nutritious would allow us to reduce the amount of grain and therefore land needed for food. Feed additives such as algae are also being developed. Tests show these can reduce methane emissions by up to 30%.
We also need to redirect subsidies and other incentives to currently under-produced crops that underpin healthy diets – notably, fruits, vegetables and nuts – rather than crops whose overconsumption drives poor health.
4. Safeguard our land and oceans
There is essentially no additional land to spare for further agricultural expansion. Degraded land must be restored or reforested. Specific strategies for curbing biodiversity loss include keeping half of the current global land area for nature, while sharing space on cultivated lands.
The same applies for our oceans. We need to protect the marine ecosystems fisheries depend on. Fish stocks must be kept at sustainable levels, while aquaculture – which currently provides more than 40% of all fish consumed – must incorporate “circular production”. This includes strategies such as sourcing protein-rich feeds from insects grown on food waste.
5. Radically reduce food losses and waste
We need to more than halve our food losses and waste.
Poor harvest scheduling, careless handling of produce and inadequate cooling and storage are some of the reasons why food is lost. Similarly, consumers must start throwing less food away. This means being more conscious about portions, better consumer understanding of “best before” and “use by” labels, and embracing the opportunities that lie in leftovers.
Circular food systems that innovate new ways to reduce or eliminate waste through reuse will also play a significant role and will additionally open new business opportunities.
For significant transformation to happen, all levels of society must be engaged, from individual consumers to policymakers and everybody along the food supply chain. These changes will not happen overnight, and they are not the responsibility of a handful of stakeholders. When it comes to food and sustainability, we are all at the decision dining table.
The EAT-Lancet Commission’s Australian launch is in Melbourne on February 1. Limited free tickets are available.
Alessandro R Demaio, Australian Medical Doctor; Fellow in Global Health & NCDs, University of Copenhagen; Jessica Fanzo, Bloomberg Distinguished Associate Professor of Global Food and Agriculture Policy and Ethics, Johns Hopkins University, and Mario Herrero, Chief Research Scientist, Food Systems and the Environment, CSIRO
What did you have for dinner last night? Might you have made a different choice if you had a simple way to compare the environmental impacts of different foods?
Most people do not recognise the environmental impact of their food choices. Our research, published in Nature Climate Change, shows that even when consumers do stop to think about the greenhouse gas emissions associated with their food, they tend to underestimate it.
Fortunately, our study also points to a potential solution. We found that a simple “carbon label” can nudge consumers in the right direction, just as nutrition information helps to highlight healthier options.
Most food production is highly industrialised, and has environmental impacts that most people do not consider. In many parts of the world, conversion of land for beef and agricultural production is a major cause of deforestation. Natural gas is a key input in the manufacture of fertiliser. Refrigeration and transportation also depend heavily on fossil fuels.
Overall, food production contributes 19-29% of global greenhouse emissions. The biggest contributor is meat, particularly red meat. Cattle raised for beef and dairy products are major sources of methane, a potent greenhouse gas.
Meat production is inherently inefficient: fertiliser is used to grow feedstock, but only a small portion of this feed becomes animal protein. It takes about 38 kilograms of plant-based protein to produce 1kg of beef – an efficiency of just 3%. For comparison, pork has 9% efficiency and poultry has 13%.
We could therefore cut greenhouse emissions from food significantly by opting for more vegetarian or vegan meals.
Food for thought
To find out whether consumers appreciate the environmental impact of their food choices, we asked 512 US volunteers to estimate the greenhouse emissions of 19 common foods and 18 typical household appliances.
We told the respondents that a 100-watt incandescent light bulb turned on for 1 hour produces 100 “greenhouse gas emission units”, and asked them to make estimates about the other items using this reference unit. In these terms, a serving of beef produces 2,481 emission units.
As shown below, participants underestimated the true greenhouse gas emissions of foods and appliances in almost every case. For example, the average estimate for a serving of beef was around 130 emission units – more than an order of magnitude less than the true amount. Crucially, foods were much more underestimated than appliances.
Improving consumers’ knowledge
People often overestimate their understanding of common everyday objects and processes. You might think you have a pretty solid idea of how a toilet works, until you are asked to describe it in exact detail.
Food is a similarly familiar but complex phenomenon. We eat it every day, but its production and distribution processes are largely hidden. Unlike appliances, which have energy labels, are plugged into an electrical outlet, emit heat, and generally have clear indications of when they are using electricity, the release of greenhouse gases in the production and transportation of food is invisible.
One way to influence food choice is through labelling. We designed a new carbon label to communicate information about the total amount of greenhouse emissions involved in the production and transport of food.
Drawing on knowledge from the design of existing labels for nutrition, fuel economy and energy efficiency, we came up with the label shown below. It has two key features.
First, it translates greenhouse emissions into a concrete, familiar unit: equivalent number of light bulb minutes. A serving of beef and vegetable soup, for example, is roughly equivalent to a light bulb turned on for 2,127 minutes – or almost 36 hours.
Second, it displays the food’s relative environmental impact compared with other food, on an 11-point scale from green (low impact) to red (high impact). Our serving of beef and vegetable soup rates at 10 on the scale – deep into the red zone – because beef production is so emissions-intensive.
To test the label, we asked 120 US volunteers to buy cans of soup from a selection of six. Half of the soups contained beef and the other half were vegetarian. Everyone was presented with price and standard nutritional information. Half of the group was also presented with our new carbon labels.
Volunteers who were shown the carbon labels chose significantly fewer beef soup options. Importantly, they also had more accurate perceptions of the relative carbon footprints of the different soups on offer.
Figuring out the carbon footprint of every food item is difficult, expensive, and fraught with uncertainty. But we believe a simplified carbon label – perhaps using a traffic light system or showing relative scores for different foods – can help inform and empower consumers to reduce the environmental impact of their food choices.
Adrian R. Camilleri, Senior Lecturer in Marketing, University of Technology Sydney; Dalia Patino-Echeverri, Associate professor, Duke University, and Rick Larrick, Professor of Management and Organizations, Duke University
Globally, one-third of food produced for human consumption is wasted. Food waste costs Australia A$20 billion each year and is damaging our planet’s resources by contributing to climate change and inefficient land, fertiliser and freshwater use.
And it’s estimated if no further action is taken to slow rising obesity rates, it will cost Australia A$87.7 billion over the next ten years. Preventable chronic diseases are Australia’s leading cause of ill health, and conditions such as coronary heart disease, stroke, high blood pressure, some forms of cancer and type 2 diabetes are linked to obesity and unhealthy diets.
But we can tackle these two major issues of obesity and food waste together.
Avoid over-consumption of food
Described as metabolic food waste, the consumption of food in excess of nutritional requirements uses valuable food system resources and manifests as overweight and obesity.
The first of the Australian dietary guidelines is:
To achieve and maintain a healthy weight, be physically active and choose amounts of nutritious food and drinks to meet your energy needs.
In 2013, researchers defined three principles for a healthy and sustainable diet. The first was:
Any food that is consumed above a person’s energy requirement represents an avoidable environmental burden in the form of greenhouse gas emissions, use of natural resources and pressure on biodiversity.
Reduce consumption of processed, packaged foods
Ultra-processed foods are not only promoting obesity, they pose a great threat to our environment. The damage to our planet not only lies in the manufacture and distribution of these foods but also in their disposal. Food packaging (bottles, containers, wrappers) accounts for almost two-thirds of total packaging waste by volume.
Ultra-processed foods are high in calories, refined sugar, saturated fat and salt, and they’re dominating Australia’s food supply. These products are formulated and marketed to promote over-consumption, contributing to our obesity epidemic.
Healthy and sustainable dietary recommendations promote the consumption of fewer processed foods, which are energy-dense, highly processed and packaged. This ultimately reduces both the risk of dietary imbalances and the unnecessary use of environmental resources.
Author Michael Pollan put it best when he said, “Don’t eat anything your great-grandmother wouldn’t recognise as food.”
So what do we need to do?
In response to the financial and environmental burden of food waste, the federal government’s National Food Waste Strategy aims to halve food waste in Australia by 2030. A$133 million has been allocated over the next decade to a research centre which can assist the environment, public health and economic sectors to work together to address both food waste and obesity.
One of Brazil’s five guiding principles states that dietary recommendations must take into account the impact of the means of production and distribution on social justice and the environment. The Qatar national dietary guidelines explicitly state “reduce leftovers and waste”.
Many would be surprised to learn Australia’s dietary guidelines include tips to minimise food waste:
store food appropriately, dispose of food waste appropriately (e.g. compost, worm farms), keep food safely and select foods with appropriate packaging and recycle.
These recommendations are hidden in Appendix G of our guidelines, despite efforts from leading advocates to give them a more prominent position. To follow international precedence, these recommendations should be moved to a prominent location in our guidelines.
At a local government level, councils can encourage responsible practices to minimise food waste by subsidising worm farms and compost bins, arranging kerbside collection of food scraps and enabling better access to soft plastic recycling programs such as Red Cycle.
Portion and serving sizes should be considered by commercial food settings. Every year Australians eat 2.5 billion meals out and waste 2.2 million tonnes of food via the commercial and industrial sectors. Evidence shows reducing portion sizes in food service settings leads to a reduction in both plate waste and over-consumption.
Given the cost of food waste and obesity to the economy, and the impact on the health of our people and our planet, reducing food waste can address two major problems facing humanity today.
Following our annual Christmas overindulgence, many of us have set ambitious goals for the year ahead. But eating healthy shouldn’t just mean cutting down on snacks; given the environmental impact of food production, a more sustainable diet should feature high on everyone’s list of New Year’s resolutions.
Australians have one of the largest per capita dietary environmental footprints in the world, so there’s definitely room for improvement. But, as with all diets, radical and sudden changes like going vegan or vegetarian are notoriously difficult.
Smaller, more achievable behavioural shifts are more realistic. This also makes sense from an environmental perspective – large-scale drastic changes might end up shifting one type of environmental impact to another.
This guide is about making informed, feasible changes towards a more environmentally sustainable diet. It starts with the food items you put in your shopping basket.
Meat, junk and waste
Sustainability researchers, like myself, track the life cycle of food from farm to fork, measuring the energy used and emissions generated by the entire process.
There are many reasons our diets have such a large environmental impact, but one of the biggest is that we’re a nation of meat eaters. On average, an Aussie eats 95kg of meat a year, significantly more than the OECD average of 69kg.
Generally, animal-derived foods require more energy and resources and release significantly more emissions than most plant foods. This is particularly true for red meat: the current average consumption is 24% higher than the maximum recommended intake.
Another reason is our overconsumption of total calories, often driven by junk foods. Eating more food than we need means the environmental resources used in producing that extra food are wasted. It also leads to a range of health problems such as obesity.
What is realistic dietary change?
Sustainable dietary choices aren’t just about environmental impact – it also means being realistic and consistent. Only 11% of Australians are vegetarian, so expecting a majority to drastically reduce meat consumption is impractical, and probably alienating.
Alternatives like flexitarianism (eating meat more rarely) are more achievable for most.
An added complication is that most Australian cows are raised on pasture, which has a high carbon footprint but requires less water than growing many plant foods. So, the complete substitution of red meat or dairy with plant-based products could simply change one environmental impact for another.
Putting it all together – simple shopping advice
Moderation: Cutting out staples of the Australian diet, like meat, is not a realistic goal for many people. But try moderating your cmeat that has the highest environmental impact (beef and lamb) and instead go for chicken or pork.
Reducing junk food is good for your wallet, waist and the environment. Processed meats or dairy-based desserts have the highest footprints amongst junk foods, so when the urge to indulge hits, go for fruit-only desserts such as sorbets. Or just buy more fruit to freeze and turn into delicious and healthy smoothies that you can enjoy even more regularly. (Grapes are very high in sugar, and when frozen are great summer treats.)
Meal planning can also help cut down food waste, so it might be worth trying a pantry planning app.
Substitution: Think about your favourite recipes, and how you can swap out the most resource-greedy ingredients. Some meats can be replaced with alternative sources of protein such as legumes and nuts.
Sustainably-farmed or sourced seafood is another protein alternative with a lower environmental footprint compared to meat, as long as you choose your seafood wisely – for canned tuna make sure to check the label! Seasonal produce usually requires fewer resources and needs to travel less to the store, so it’s worth checking a guide to what’s in season in your region.
Complex packaging of many food products, which is often unnecessary, also contributes to their environmental impact. Opt for loose fruit and vegetables and take your own shopping bags.
Experimentation: When you do buy meat, opt for novel protein sources such as game meat – we are lucky to have an abundance of kangaroo as a more sustainable protein alternative in Australia. If you’re feeling even more adventurous, you could also try some insects.
This guide is a starting point for thinking about a more sustainable diet, but food systems are incredibly complex. Animal welfare and the viability of farming communities are just part of the social and economic issues we much deal with.
Ultimately, while consumers can drive change, this will be incremental: transformative change can only be achieved by food producers and retailers also coming on board to drive a more sustainable food system.
Last night I cooked my family a delicious pasta dinner using biogas energy. This morning we all had eggs cooked on biogas. I’m not sure what’s for dinner tonight, but I know what will provide the energy for cooking: biogas.
And not just any biogas – it’s home biogas, produced in our suburban backyard, as part of my ongoing “action research” into sustainable energy practices.
In an age of worrying climate change and looming fossil energy decline, the benefits of biogas are obvious. It is a renewable energy source with zero net greenhouse emissions. And yet its potential has largely gone untapped, at least in the developed world.
Based on my research and experience, I contend that home-produced biogas is an extremely promising technology whose time has come. In fact, I believe it could provoke a domestic green energy revolution, if only we let it.
What is biogas?
Biogas is produced when organic matter biodegrades under anaerobic conditions (that is, in the absence of oxygen). This process produces a mixture of gases – primarily methane, some carbon dioxide and tiny portions of other gases such as hydrogen sulfide.
When the biogas is filtered to remove the hydrogen sulfide, the resulting mixture can be burned as an energy source for cooking, lighting, or heating water or space. When compressed it can be used as fuel for vehicles. On a commercial scale biogas can be used to generate electricity or even refined and fed into the gas grid.
The types of organic matter used to produce biogas include food waste, animal manure and agricultural byproducts. Some commercial systems use sewage to produce and capture biogas.
The primary benefit of biogas is that it is renewable. Whereas the production of oil and other fossil fuels will eventually peak and decline, we will always be able to make biogas as long as the sun is shining and plants can grow.
Biogas has zero net greenhouse emissions because the CO₂ that is released into the atmosphere when it burns is no more than what was drawn down from the atmosphere when the organic matter was first grown.
As already noted, when organic matter biodegrades under anaerobic conditions, methane is produced. It has been estimated that each year between 590 million and 800 million tones of methane is released into the atmosphere. This is bad news for the climate – pound for pound, methane is a far more potent greenhouse gas than CO₂.
But in a biogas system this methane is captured and ultimately converted to CO₂ when the fuel is burned. Because that CO₂ was going to end up in the atmosphere anyway through natural degradation, biogas has zero net emissions.
There are other benefits too. The organic matter used in biogas digesters is typically a waste product. By using biogas we can reduce the amount of food waste and other organic materials being sent to landfill.
Furthermore, biogas systems produce a nutrient-rich sludge that can be watered down into a fertiliser for gardens or farms. All of this can help to develop increased energy independence, build resilience and save money.
My biogas experiment
In the spirit of scientific research, I installed one of the few home biogas systems currently available, at a cost of just over A$1,000 delivered, and have been impressed by its ease and functionality. (Please note that I have no affiliation, commercial or otherwise, with the manufacturer.)
In practical terms, I put in about 2kg of food waste each day and so far I have had enough gas to cook with, sometimes twice a day. If I ever needed more gas, I could put in more organic matter. I will continue to monitor the system as part of my research and will publish updates in due course. If interested, watch this space.
My personal motivation to explore biogas (related to my research) arises primarily from a desire to decarbonise my household’s energy use. So far, so good. We have disconnected from the conventional gas grid and now have more money to spend on projects such as expanding our solar array.
Given the alarming levels of food waste in Australia, I also like the idea of turning this waste into green energy. My neighbours kindly donate their organic matter to supplement our own inputs, increasing community engagement. When necessary I cycle to my local vegetable market and enthusiastically jump into their large food waste bin to take what I need, with permission.
They think I’m mad. But, then, I think using fossil fuels is mad.
Hurdles and hopes
Home biogas is widely produced in developing regions of the world. The World Bank and the United Nations actively encourage its use as a cheap, clean energy source. China has 27 million biogas plants.
But developed regions, including Australia, have been slow to exploit this vast potential. Given that Australia is one of the most carbon-intensive countries on Earth, this is unfortunate.
The failure to embrace home biogas is partly due to a lack of clear regulations about its use. Where is the Home Biogas Act? Almost every Australian backyard has an independent gas bottle to power the ubiquitous barbecue, so clearly storing gas in the backyard is not a problem. My biogas system came with robust safety certificates, warranties and insurance, and these systems do not feature high-pressure gas pipes.
Home biogas production is unusual. But I believe that state governments should draw up legislation to accommodate it, and that local councils should offer advice and assistance to householders who are interested in taking it up. Hoping for progress in this regard, I recently made a submission to the Victorian government as part of its Waste to Energy consultations.
My own carefully managed experiment demonstrates how home biogas can be used safely and successfully. Nevertheless, biogas is a combustible fuel and needs to be filtered for poisonous hydrogen sulfide. Like any fuel, it should be respected and used responsibly. But biogas need not be feared. Fossil gas is far more dangerous anyway.
Climate change and extreme weather events are already impacting our food, from meat and vegetables, right through to wine. In our series on the Climate and Food, we’re looking at what this means for the food chain.
The concentration of carbon dioxide in our atmosphere is increasing. Everything else being equal, higher CO₂ levels will increase the yields of major crops such as wheat, barley and pulses. But the trade-off is a hit to the quality and nutritional content of some of our favourite foods.
In our research at the Australian Grains Free Air CO₂ Enrichment (AGFACE) facility, we at Agriculture Victoria and The University of Melbourne are mimicking the CO₂ levels likely to be found in the year 2050. CO₂ levels currently stand at 406 parts per million (PPM) and are expected to rise to 550PPM by 2050. We have found that elevated levels of CO₂ will reduce the concentration of grain protein and micronutrients like zinc and iron, in cereals (pulses are less affected).
The degree to which protein is affected by CO₂ depends on the temperature and available water. In wet years there will be a smaller impact than in drier years. But over nine years of research we have shown that the average decrease in grain protein content is 6% when there is elevated CO₂.
Because a decrease in protein content under elevated CO2 can be more severe in dry conditions, Australia could be particularly affected. Unless ways are found to ameliorate the decrease in protein through plant breeding and agronomy, Australia’s dry conditions may put it at a competitive disadvantage, since grain quality is likely to decrease more than in other parts of the world with more favourable growing conditions.
There are several different classes of wheat – some are good for making bread, others for noodles etc. The amount of protein is one of the factors that sets some wheat apart from others.
Although a 6% average decrease in grain protein content may not seem large, it could result in a lot of Australian wheat being downgraded. Some regions may be completely unable to grow wheat of high enough quality to make bread.
But the protein reduction in our wheat will become manifest in a number of ways. As many farmers are paid premiums for high protein concentrations, their incomes could suffer. Our exports will also take a hit, as markets prefer high-protein wheat. For consumers, we could see the reduction in bread quality (the best bread flours are high-protein) and nutrition. Loaf volume and texture may be different but it is unclear whether taste will be affected.
The main measure of this is loaf volume and texture, but the degree of decrease is affected by crop variety. A decrease in grain protein concentration is one factor affecting loaf volume, but dough characteristics (such as elasticity) are also degraded by changes in the protein make-up of grain. This alters the composition of glutenin and gliadin proteins which are the predominant proteins in gluten. To maintain bread quality when lower quality flour is used, bakers can add gluten, but if gluten characteristics are changed, this may not achieve the desired dough characteristics for high quality bread. Even if adding extra gluten remedies poor loaf quality, it adds extra expense to the baking process.
Nutrition will also be affected by reduced grain protein, particularly in developing areas with more limited access to food. This is a major food security concern. If grain protein concentration decreases, people with less access to food may need to consume more (at more cost) in order to meet their basic nutritional needs. Reduced micronutrients, notably zinc and iron, could affect health, particularly in Africa. This is being addressed by international efforts biofortification and selection of iron and zinc rich varieties, but it is unknown whether such efforts will be successful as CO₂ levels increase.
What can we do about it?
Farmers have always been adaptive and responsive to changes and it is possible management of nitrogen fertilisers could minimise the reduction in grain protein. Research we are conducting shows, however, that adding additional fertiliser has less effect under elevated CO₂ conditions than under current CO₂ levels. There may be fundamental physiological changes and bottlenecks under elevated CO₂ that are not yet well understood.
If management through nitrogen-based fertilisation either cannot, or can only partly, increases grain protein, then we must question whether plant breeding can keep up with the rapid increase in CO₂. Are there traits that are not being considered but that could optimise the positives and reduce the negative impacts?
Selection for high protein wheat varieties often results in a decrease in yield. This relationship is referred to as the yield-protein conundrum. A lot of effort has gone into finding varieties that increase protein while maintaining yields. We have yet to find real success down this path.
A combination of management adaptation and breeding may be able to maintain grain protein while still increasing yields. But, there are unknowns under elevated CO₂such as whether protein make-up is altered, and whether there are limitations in the plant to how protein is manufactured under elevated CO2. We may require active selection and more extensive testing of traits and management practices to understand whether varieties selected now will still respond as expected under future CO₂ conditions.
Finally, to maintain bread quality we should rethink our intentions. Not all wheat needs to be destined for bread. But, for Australia to remain competitive in international markets, plant breeders may need to select varieties with higher grain protein concentrations under elevated CO2 conditions, focusing on varieties that contain the specific gluten protein combinations necessary for a delicious loaf.