New study: changes in climate since 2000 have cut Australian farm profits 22%

The Australian Bureau of Agricultural and Resource Economics and Sciences farmpredict model finds that changes in climate conditions since 2000 have cut farm profits by 22% overall, and by 35% for cropping farms..
ABARES/Shutterstock

Neal Hughes, Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES) and Steve Hatfield-Dodds, Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES)

The current drought across much of eastern Australia has demonstrated the dramatic effects climate variability can have on farm businesses and households.

The drought has also renewed longstanding discussions around the emerging effects of climate change on agriculture, and how governments can best help farmers to manage drought risk.

A new study released this morning by the Australian Bureau of Agricultural and Resource Economics and Sciences offers fresh insight on these issues by quantifying the impacts of recent climate variability on the profits of Australian broadacre farms.

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The results show that changes in temperature and rainfall over the past 20 years have had a negative effect on average farm profits while also increasing risk.

The findings demonstrate the importance of adaptation, innovation and adjustment to the agriculture sector, and the need for policy responses which promote – and don’t unnecessarily inhibit – such progress.

Measuring the effects of climate on farms

Measuring the effects of climate on farms is difficult given the many other factors that also influence farm performance, including commodity prices.

Further, the effects of rainfall and temperature on farm production and profit can be complex and highly location and farm specific.

To address this complexity, ABARES has developed a model based on more than 30 years of historical farm and climate data—farmpredict — which can identify effects of climate variability, input and output prices, and other factors on different types of farms.

Cropping farms most exposed

The model finds that cropping farms generally face greater climate risk than beef farms, but also generate higher average returns.

Cropping farm revenue and profits are lower in dry years, with large reductions in crop yields and only small savings in input costs.

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Effect of climate variability on rate of return

Based on historical climate conditions (1950 to 2019), holding non-climate factors constant. See report for more detail. ABARES FarmPredict

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In contrast, drought has a smaller immediate effect on beef farm revenue, because in dry years farmers can increase the quantity of livestock sold.

However, drought also lowers herd numbers, which lowers farm profit when herd value is accounted for.

Higher temperatures, lower winter rainfall

Australian average temperatures have increased by about 1°C since 1950.

Recent decades have also seen a trend towards lower average winter rainfall in the southwest and southeast.

This drying trend has been linked to atmospheric changes associated with global warming.

However, while global climate models generally predict a decline in winter season rainfall across southern Australia and more time spent in drought, there is still much uncertainty about what will happen in the long term, particularly to rainfall.

Climate shifts have cut farm profits

ABARES has assessed the effect of climate variability on farm profits over the period 1950 to 2019, holding all other factors constant including commodity prices and farm management practices.

We find that the shift in climate conditions since 2000 (from conditions in the period 1950-1999 to conditions in the period 2000-2019) has had a negative effect on the profits of both cropping and livestock farms.

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Effect of 2000 – 2019 climate conditions on average farm profit

“Farm profit percentiles for the period 2000-2019 relative to 1950-1999, holding non-climate factors constant. See report for more detail. ABARES

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We estimate that the shift in climate has cut average annual broadacre farm profits by around 22%, which is an average of $18,600 per farm per year, controlling for all other factors.

The effects have been most pronounced in the cropping sector, reducing average profits by 35%, or $70,900 a year for a typical cropping farm.

At a national level this amounts to an average loss in production of broadacre crops of around $1.1 billion a year.

Although beef farms have been less affected than cropping farms overall, some beef farming regions have been affected more than others, especially south-western Queensland.

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Like previous ABARES research this study finds evidence of adaptation, with farmers reducing their sensitivity to dry conditions over time.

Our results suggest that without this adaptation the effects of the post-2000 climate shift would have been considerably larger, particularly for cropping farms.

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Effect of post-2000 climate on average annual farm profits

Per cent change relative to 1950-1999 climate, holding non-climate factors constant. See report for more detail. ABARES FarmPredict

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Risk and income volatility have also increased

The changed climate conditions since 2000 have also increased risk and income volatility.

This is particularly so for cropping farms, where we find the chance of low-profit years has more than doubled as a result of the change in climate conditions.

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Effect of climate variability on typical cropping farm

Distribution of farm profits for 1950-1999 climate and 2000-2019 climate. See report for more detail. ABARES FarmPredict

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Handle with care – the drought policy dilemma

Drought policy faces an almost unavoidable dilemma, that providing relief to farm businesses and households in times of drought risks slowing industry structural adjustment and innovation.

Adjustment, change and innovation are fundamental to improving agricultural productivity; maintaining Australia’s competitiveness in world markets; and providing attractive and financially sustainable opportunities for farm households.

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Helping farmers in distress doesn’t help them be the best: the drought relief dilemma

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For these reasons, the strategic intent of drought policy has shifted away from seeking to protect and insulate farmers towards the promotion of drought preparedness and self‑reliance.

The best options for reconciling the drought policy dilemma focus on boosting the resilience of farm businesses and households to future droughts and climate variability, including through action and investment when farmers are not in drought.

The government’s Future Drought Fund, which will support research and innovation, is a good example of this approach.

Developing new insurance options is one worthwhile avenue of research which could provide farmers a way to self-manage risk. It would require investments in data and knowledge to support viable weather insurance markets: where farmers pay premiums sufficient to cover costs over time.

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Better data would help crack the drought insurance problem

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Supporting farm households experiencing hardship is legitimate and important, but for the long term health of the farm sector this needs to be done in ways that promote resilience and improved productivity and allow for long term adjustment to change.

Neal Hughes, Senior Economist, Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES) and Steve Hatfield-Dodds, Executive Director, Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES)

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Early sowing can help save Australia’s wheat from climate change

Timing is of the essence when it comes to growing wheat.
Author provided

James Hunt, La Trobe University

Climate change has already reduced yields for Australian wheat growers, thanks to increasingly unreliable rains and hostile temperatures. But our new research offers farmers a way to adapt.

By sowing much earlier than they currently do, wheat growers can potentially increase yields again. However, our study published today in Nature Climate Change shows that to do this they need new varieties that allow them more leeway to vary their sowing dates in the face of increasingly erratic rainfall.

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Sowing wheat is a matter of delicate timing. Seeds of current varieties need to be planted at just such a time so that, months later, the plants flower during a window of just 1-2 weeks, known as the optimal flowering period.

In Australia’s wheat belt this window is generally in early spring. At this time the soil is moist after the cool, wet winter; days are getting longer and sunnier; maximum temperatures are still relatively low; and frosts are less frequent. If crops flower outside the optimal window, yields decline sharply.

Crops and colonies

When Europeans first started trying to grow wheat in Australia, they used varieties that were suited to the cool, wet climate of northern Europe, where the optimal flowering period is in summer. These varieties were much too slow to flower in Australian conditions, and yields were very low. Wheat breeder William Farrer used faster-developing wheats from India to create the Federation variety, which revolutionised wheat production in Australia, earning Farrer the ultimate honour of having a pub named after him.

Federation wheat is a “spring wheat”, moving rapidly through its life cycle regardless of when it is planted. If you sow it earlier, it flowers earlier. For more than a century Australian wheat breeders have bred spring wheats, allowing growers to adjust their sowing time to get their crops to flower during the optimal period. Anzac Day has traditionally been the start of sowing season, after autumn rains have wet the soil enough for seeds to germinate.

Here is where climate change is causing a problem. If farmers sow later than mid-May, the wheat is likely to miss its spring flowering window. But southern Australia has experienced declining April and May rainfall, making it harder for growers to sow and establish crops at the right time. This in turn means crops flower too late the following spring, meaning yields are reduced by drought and heat.

Growers could start sowing earlier, and use stored soil water from summer rain (which hasn’t declined and has even increased at some locations), but current spring wheat varieties would flower too early to yield well. For farmers to sow earlier, they need a different sort of wheat in which development is slowed down by an environmental cue. One such environmental cue is called vernalisation. Plants that are sensitive to vernalisation will not flower until they have experienced a period of cold temperatures. These strains are thus called “winter wheats”.

Ironically enough, the wheat varieties that Europeans first brought to Australia were winter wheats, but they were further slowed by sensitivity to day length which made them too slow to reach the earlier flowering times needed in the hotter, drier colony.

But this problem can be sidestepped by using a “fast winter wheat”, which is sensitive to vernalisation but not to day length. Our previous research showed that this type of wheat was very suited to Australian conditions – it can be sown early but still flower at the right time. In fact, the vernalisation requirement means that this wheat can be sown over a much broader range of dates and experience fluctuating temperatures, and still flower at the right time.

Yielding results

In our new research, we developed different lines of wheat that varied in their response to vernalisation and day length, and grew them across the wheat belt to compare which ones would yield best at earlier sowing times.

We found that a fast winter wheat performed best over most of the wheatbelt, and on average yielded 10% more than spring wheat when they flower at the same time.

We then used computer simulations to investigate how these crops would perform at the scale of an entire farm. Our results showed that if Australian growers had access to adapted winter varieties in addition to spring varieties, they could start sowing earlier in seasons where there was an opportunity. If the rains come early, farmers can use the winter wheat; if they come late they can switch to the spring wheat, which yields better than winter wheat at late sowing times.

This would mean that more area of crop would be planted on time, and yields would increase as a result. If realised, this could increase national wheat production by about 20%, or roughly 7.1 million tonnes.

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Australia’s farming future: can our wheat keep feeding the world?

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The main hurdle is that growers do not currently have access to suitable winter wheats. Breeding companies have started work on them, but it will be several years before suitably high-quality varieties become available.

Australian growers urgently need to keep pace with climate change. Although Australia only produces 4% of the world’s wheat, it accounts for 10% of exports and is thus important in determining global supply and price. If global wheat supply is low, prices rise, and it becomes unaffordable for many of the world’s poorest people, potentially causing malnutrition and civil unrest. Steeply rising wheat prices were among the factors behind the food riots that broke out in more than 40 countries in 2007-08, which helped to trigger the Arab Spring uprisings of 2010-12.

The world’s poorest people deserve to be able to buy wheat. But Australian wheat farmers also need to earn a decent living and stay internationally competitive. The only way to meet all these needs is to keep production costs low – and increasing yields by sowing the right wheat cultivars for Australia’s changing climate is one way to go about it.

James Hunt, Associate Professor, La Trobe University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How to grow crops on Mars if we are to live on the red planet

We can create the right kind of food plants to survive on Mars.
Shutterstock/SergeyDV

Briardo Llorente, Macquarie University

Preparations are already underway for missions that will land humans on Mars in a decade or so. But what would people eat if these missions eventually lead to the permanent colonisation of the red planet?

Once (if) humans do make it to Mars, a major challenge for any colony will be to generate a stable supply of food. The enormous costs of launching and resupplying resources from Earth will make that impractical.

Humans on Mars will need to move away from complete reliance on shipped cargo, and achieve a high level of self-sufficient and sustainable agriculture.

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Discovered: a huge liquid water lake beneath the southern pole of Mars

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The recent discovery of liquid water on Mars – which adds new information to the question of whether we will find life on the planet – does raise the possibility of using such supplies to help grow food.

But water is only one of many things we will need if we’re to grow enough food on Mars.

What sort of food?

Previous work has suggested the use of microbes as a source of food on Mars. The use of hydroponic greenhouses and controlled environmental systems, similar to one being tested onboard the International Space Station to grow crops, is another option.

This month, in the journal Genes, we provide a new perspective based on the use of advanced synthetic biology to improve the potential performance of plant life on Mars.

Synthetic biology is a fast-growing field. It combines principles from engineering, DNA science, and computer science (among many other disciplines) to impart new and improved functions to living organisms.

Not only can we read DNA, but we can also design biological systems, test them, and even engineer whole organisms. Yeast is just one example of an industrial workhorse microbe whose whole genome is currently being re-engineered by an international consortium.

The technology has progressed so far that precision genetic engineering and automation can now be merged into automated robotic facilities, known as biofoundries.

These biofoundries can test millions of DNA designs in parallel to find the organisms with the qualities that we are looking for.

Mars: Earth-like but not Earth

Although Mars is the most Earth-like of our neighbouring planets, Mars and Earth differ in many ways.

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The gravity on Mars is around a third of that on Earth. Mars receives about half of the sunlight we get on Earth, but much higher levels of harmful ultraviolet (UV) and cosmic rays. The surface temperature of Mars is about -60℃ and it has a thin atmosphere primarily made of carbon dioxide.

Unlike Earth’s soil, which is humid and rich in nutrients and microorganisms that support plant growth, Mars is covered with regolith. This is an arid material that contains perchlorate chemicals that are toxic to humans.

Also – despite the latest sub-surface lake find – water on Mars mostly exists in the form of ice, and the low atmospheric pressure of the planet makes liquid water boil at around 5℃.

Plants on Earth have evolved for hundreds of millions of years and are adapted to terrestrial conditions, but they will not grow well on Mars.

This means that substantial resources that would be scarce and priceless for humans on Mars, like liquid water and energy, would need to be allocated to achieve efficient farming by artificially creating optimal plant growth conditions.

Adapting plants to Mars

A more rational alternative is to use synthetic biology to develop crops specifically for Mars. This formidable challenge can be tackled and fast-tracked by building a plant-focused Mars biofoundry.

Such an automated facility would be capable of expediting the engineering of biological designs and testing of their performance under simulated Martian conditions.

With adequate funding and active international collaboration, such an advanced facility could improve many of the traits required for making crops thrive on Mars within a decade.

This includes improving photosynthesis and photoprotection (to help protect plants from sunlight and UV rays), as well as drought and cold tolerance in plants, and engineering high-yield functional crops. We also need to modify microbes to detoxify and improve the Martian soil quality.

These are all challenges that are within the capability of modern synthetic biology.

Benefits for Earth

Developing the next generation of crops required for sustaining humans on Mars would also have great benefits for people on Earth.

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Before we colonise Mars, let’s look to our problems on Earth

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The growing global population is increasing the demand for food. To meet this demand we must increase agricultural productivity, but we have to do so without negatively impacting our environment.

The best way to achieve these goals would be to improve the crops that are already widely used. Setting up facilities such as the proposed Mars Biofoundry would bring immense benefit to the turnaround time of plant research with implications for food security and environmental protection.

So ultimately, the main beneficiary of efforts to develop crops for Mars would be Earth.

Briardo Llorente, CSIRO Synthetic Biology Future Science Fellow, Macquarie University

This article was originally published on The Conversation. Read the original article.

The secret agents protecting our crops and gardens

Lacewings are fantastic predators and are easy to rear and release.
Dan Papacek & Tony Meredith (Bugs for Bugs), Author provided

Lizzy Lowe, Macquarie University and Manu Saunders, University of New England

Insect pests cause a huge amount of damage to crops globally. In Australia alone, pests are responsible for around A$360 million of crop losses a year. Controlling pest outbreaks is crucial for food security and human health. Since the 1940s, our primary defence against crop pests has been synthetic pesticides. But using pesticides comes at a huge cost.

Not all bugs are bad!

Bees, flies and butterflies help to pollinate our plants. Decomposers like beetles and worms help break down wastes and return nutrients to the soil. Meanwhile, predators and parasites help control the species that are pests. One of the biggest environmental problems with pesticides is that they can affect these beneficial species as well as the pests they’re targeting.

Predatory insects and spiders control pests with none of the health and environmental risks of chemicals. So when we kill these species with insecticides, we are shooting ourselves in the foot.

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The real cost of pesticides in Australia’s food boom

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Losing insects also has flow-on effects for larger animals that rely on them for food. Because invertebrates have such important roles to play in our environment, losing them to insecticides can completely change how ecosystems function.

An alternative to insecticides

Biological control (or biocontrol) relies on “secret agents” – the natural enemies (predators and parasitoids) of pests that live freely in the ecosystems around us.

There is a huge range of predatory invertebrates that eat pests. They include dragonflies, preying mantids, beetles (including ladybugs), lacewings, spiders, mites, wasps, and even some flies.

Parasitoids, meanwhile, are insects that lay their eggs in the bodies of other invertebrates. Their larvae extract nutrients from the host during their development, which ultimately kills the host. Wasps are best known for this strategy but there are also parasitoid flies and beetles.

Lady birds are voracious predators ready to eat pests in crops and gardens.
Manu Saunders

Predators and parasitoids are useful because they use pest insects, like caterpillars and aphids, as food to reproduce and grow their populations. We walk past many of these hard working agents every day without knowing it.

One biocontrol method that gardeners and land managers use is called augmentation. This simply means raising lots of live individuals of particular natural enemies, like ladybirds or wasps, and releasing them into an area to control pests.

Alternatively, gardeners might change the local environment to encourage these natural enemies to move in on their own. They might include natural insectariums or planting different types of vegetation to encourage diverse invertebrate communities. There is increasing evidence of the success of these strategies in organic farming so we should be thinking about using them more broadly.

Selecting your insects

If you want to release biocontrol agents, you need to choose them carefully, just like human special agents. Like any introduced plant or animal, there is a risk that good bugs could become pests (if they feed on the wrong insects, for example).

Selecting biological control agents requires close collaboration between managers, skilled entomologists and other scientists. For each new species, they identify the pest and some potential predators. They look at the predator’s life cycle and resource needs, and consider how it interacts not just with pests, but with other insects too. If agents are coming in from overseas, they also need to be cleared by government biosecurity.

Parasiotid wasps, lacewings, predatory mites, ladybird beetles, and nematodes are all common biocontrol agents. These species are relatively easy to raise in large numbers and work well when released into the field. Spiders are also a really important predator of many pest insects, but they’re often overlooked in the biocontrol game because they are harder to breed – and for some reason people don’t always like releasing large numbers of spiders.

Many biocontrol agents are enemies of pests in general, preying on aphids, caterpillars and fruit flies alike. It’s important to have generalists around for every day pest control, but sometimes a more targeted approach is needed. This is when specialised predators or parasitoids come in. These are species that only target specific pests like leaf miners, beetles, scale insects or spider mites. This way the target pest can be managed with no risk of the parasitoids accidentally attacking other beneficial invertebrates.

Raising good bugs

It’s very exciting to get live insects in the mail!
Lizzy Lowe

Once a biocontrol agent has been selected, greenhouses or lab facilities start raising a large population. This is an emerging market in Australia, but there are already a number of companies in Australia who specialise in rearing biological control agents.

This is a tricky job because demand for the product is variable and is not easy to predict. Warmer seasons are the peak time for most pests, but problems can arise at any time of the year. In most cases the biocontrol company will maintain breeding colonies throughout the year and will be ready to ramp up production at a moment’s notice when a farmer identifies a pest problem. Each company usually provides 10-20 different biocontrol agents and are always looking for new species that might be useful.

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Birds, bees and bugs: your garden is an ecosystem, and it needs looking after

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When it comes to getting the agents to the farmers, the bugs can be shipped as eggs (ready to hatch on arrival), or as live adults ready to disperse and lay their own eggs. The packages are express posted in boxes designed to keep the insects cool and safe.

Once the farmer or natural resource manager receives the bugs, applying them is quite simple. The secret agents are released among the crops, usually by hand, but in some special cases they may be airlifted in via specialised drones!

Drones can be used to deploy biological control agents.
Nathan Roy (Aerobugs)

It’s important to monitor the pests and the biological control agents after release to check that the agents are working. Some farmers are happy to do this themselves but most biological control companies have experts to visit the farms and keep an eye on all parties.

Can I use good bugs in my garden?

If you have a problem with a pest like aphids it is possible to buy predators such as ladybirds or lacewings to quickly deal with the problem. But for long term pest control, there are probably already some natural enemies living in your garden! The easiest and cheapest way to help them is to put the insecticides away and ensure your garden is a friendly environment for secret agents.

Lizzy Lowe, Postdoctoral researcher, Macquarie University and Manu Saunders, Research fellow, University of New England

This article was originally published on The Conversation. Read the original article.

How climate change threatens to make our bread less tasty

Increasing carbon dioxide is impacting some of our favourite foods.

Glenn Fitzgerald, University of Melbourne

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.

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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.

Increasing carbon dioxide could impact the flour your bread.
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Food quality

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.

Will new breeds of wheat stand up to increasing carbon dioxide?

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.

Glenn Fitzgerald, Honorary Associate Professor of Agriculture and Food, University of Melbourne

This article was originally published on The Conversation. Read the original article.

As global food demand rises, climate change is hitting our staple crops

Farmers face falling crop yields and growing food demand.
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Andrew Borrell, The University of Queensland

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.

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While increases in population and wealth will lift global demand for food by up to 70% by 2050, agriculture is already feeling the effects of climate change. This is expected to continue in coming decades.

Scientists and farmers will need to act on multiple fronts to counter falling crop yields and feed more people. As with previous agricultural revolutions, we need a new set of plant characteristics to meet the challenge.

When it comes to the staple crops – wheat, rice, maize, soybean, barley and sorghum – research has found changes in rainfall and temperature explain about 30% of the yearly variation in agricultural yields. All six crops responded negatively to increasing temperatures – most likely associated with increases in crop development rates and water stress. In particular, wheat, maize and barley show a negative response to increased temperatures. But, overall, rainfall trends had only minor effects on crop yields in these studies.

Since 1950, average global temperatures have risen by roughly 0.13°C per decade. An even faster rate of roughly 0.2°C of warming per decade is expected over the next few decades.

As temperatures rise, rainfall patterns change. Increased heat also leads to greater evaporation and surface drying, which further intensifies and prolongs droughts.

A warmer atmosphere can also hold more water – about 7% more water vapour for every 1°C increase in temperature. This ultimately results in storms with more intense rainfall. A review of rainfall patterns shows changes in the amount of rainfall everywhere.

Maize yields are predicted to decline with climate change.
Shutterstock

Falling yields

Crop yields around Australia have been hard hit by recent weather. Last year, for instance, the outlook for mungbeans was excellent. But the hot, dry weather has hurt growers. The extreme conditions have reduced average yields from an expected 1-1.5 tonnes per hectare to just 0.1-0.5 tonnes per hectare.

Sorghum and cotton crops fared little better, due to depleted soil water, lack of in-crop rainfall, and extreme heat. Fruit and vegetables, from strawberries to lettuce, were also hit hard.

But the story is larger than this. Globally, production of maize and wheat between 1980 and 2008 was 3.8% and 5.5% below what we would have expected without temperature increases. One model, which combines historical crop production and weather data, projects significant reductions in production of several key African crops. For maize, the predicted decline is as much as 22% by 2050.

Feeding more people in these changing conditions is the challenge before us. It will require crops that are highly adapted to dry and hot environments. The so-called “Green Revolution” of the 1960s and 1970s created plants with short stature and enhanced responsiveness to nitrogen fertilizer.

Now, a new set of plant characteristics is needed to further increase crop yield, by making plants resilient to the challenges of a water-scarce planet.

Developing resilient crops for a highly variable climate

Resilient crops will require significant research and action on multiple fronts – to create adaptation to drought and waterlogging, and tolerance to cold, heat and salinity. Whatever we do, we also need to factor in that agriculture contributes significantly to greenhouse gas emissions (GHGs).

Scientists are meeting this challenge by creating a framework for adapting to climate change. We are identifying favourable combinations of crop varieties (genotypes) and management practices (agronomy) to work together in a complex system.

We can mitigate the effects of some climate variations with good management practices. For example, to tackle drought, we can alter planting dates, fertilizer, irrigation, row spacing, population and cropping systems.

Genotypic solutions can bolster this approach. The challenge is to identify favourable combinations of genotypes (G) and management (M) practices in a variable environment (E). Understanding the interaction between genotypes, management and the environment (GxMxE) is critical to improving grain yield under hot and dry conditions.

Genetic and management solutions can be used to develop climate-resilient crops for highly variable environments in Australia and globally. Sorghum is a great example. It is the dietary staple for over 500 million people in more than 30 countries, making it the world’s fifth-most-important crop for human consumption after rice, wheat, maize and potatoes.

‘Stay-green’ in sorghum is an example of a genetic solution to drought that has been deployed in Australia, India and sub-Saharan Africa. Crops with stay-green maintain greener stems and leaves during drought, resulting in increased stem strength, grain size and yield. This genetic solution can be combined with a management solution (e.g. reduced plant population) to optimise production and food security in highly variable and water-limited environments.

Other projects in India have found that alternate wetting and drying (AWD) irrigation in rice, compared with normal flooded production, can reduce water use by about 32%. And, by maintaining an aerobic environment in the soil, it reduces methane emissions five-fold.

Climate change, water, agriculture and food security form a critical nexus for the 21st century. We need to create and implement practices that will increase yields, while overcoming changing conditions and limiting the emissions from the agricultural sector. There is no room for complacency here.

Andrew Borrell, Associate Professor, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland; Centre Leader, Hermitage Research Facility; College of Experts, Global Change Institute, The University of Queensland

This article was originally published on The Conversation. Read the original article.

Butterflies: Genetically Modified Crops Killing Butterflies

The article below reports on how genetically modified crops are killing off Monarch Butterfly populations. There is also a simple answer to the problem revealed in the article.

For more, visit:
http://grist.org/list/study-gmo-crops-are-killing-butterflies/

BioFuel Advance: Using Kelp to Produce Ethanol

The following link is to an article about producing ethanol from seaweed, thereby reducing the need for terrestrial biofuel crops.

For more visit:
http://news.mongabay.com/2012/0120-kelp_power.html