Don’t disturb the cockatoos on your lawn, they’re probably doing all your weeding for free (from The Conversation)

Shutterstock

Gregory Moore, University of Melbourne

Australians have a love-hate relationship with sulphur-crested cockatoos, Cacatua galerita. For some, the noisy parrots are pests that destroy crops or the garden, damage homes and pull up turf at sports ovals.

For others, they’re a bunch of larrikins who love to play and are quintessentially Australian.

Along with other scientists, I had a unique opportunity during the COVID-19 lockdowns to study things that had intrigued me closer to home, perhaps for years. While isolating in the suburbs of Melbourne, I wanted to find out why cockatoos return to the same places, and what they’re after.

The answer? Onion grass, reams of it.

Onion grass is a significant weed, and I estimated in a recent paper that one bird gorges on about 200 plants per hour. A flock of about 50 birds can consume 20,000 plants in a couple of hours.

This significantly reduces the weed level and may make expensive herbicide use unnecessary. So if you have a large amount of onion grass on your property and are regularly visited by sulphur-crested cockatoos, it would be wise to let them do their weeding first.

When play verges on vandalism

Most of us see cockies whether we live in rural communities or major cities, but how much do you really know about them?

Two sulphur-crested cockatoos sitting on a branch
Sulphur-crested cockatoos nest in old hollow trees. Shutterstock

In late winter and early spring in many parts of Australia, flocks of sulphur–crested cockatoos can be seen grazing on the ground. They’re usually found close to water, nesting in woodlands with old hollow trees, such as river red gums, Eucalyptus camaldulensis.

Where these forests and trees are being cleared, the number of cockies falls. But they are resilient and adaptable birds, and have spread their range to cities and the urban fringe, where numbers are increasing.


Read more: Birds that play with others have the biggest brains – and the same may go for humans


The birds are known to play with fruits, hang upside down on branches or perform flying cartwheels by holding a small branch or powerline with their feet, flapping their wings as they do loop after loop.

Sometimes their play verges on vandalism as they follow tree planters, deftly pulling up just-planted trees and laying them neatly beside the hole.

While cockatoos feed on the fruits and seed of native species, they’ve adapted very quickly to the introduction of exotic species, such as onion grass from South Africa, which is plentiful and easy to harvest.

I observed flocks ranging from nine to 63 cockatoos at seven sites along the Maribyrnong River in Keilor last July and August. Onion grass was the only item on their menu.

A pest for humans, a feast for birds

Onion grass (Romulea rosea) is small and usually inconspicuous with grass-like leaves. It’s typically only noticed when it flowers in spring, producing pretty, pink and yellow-throated flowers.

Conspicuous onion grass with a small purple flower
Onion grass comes from South Africa, and is a big problem for native grasslands. Harry Rose/Wikimedia, CC BY

Onion grass can be a serious weed that’s very difficult to control. It’s not only a problem for agricultural land, but also for recreational turf and native grasslands.

In some areas, there are nearly 5,000 onion grass plants per square metre. This is a massive number requiring costly control measures, such as spraying or scraping away the upper layer of top soil.


Read more: The river red gum is an icon of the driest continent


Onion grass gets its name from its onion-like leaves. At the base is a small bulb, which works as a modified underground stem called a “corm”. The corm is what cockatoos will travel many kilometres for, to dig up and return to for days on end.

A brown bulb with small roots coming out
When cockatoos eat onion grass corm, it prevents the weed from regenerating. Harry Rose/Wikimedia, CC BY

Their super weeding effort

Like other native parrots, sulphur-crested cockatoos are famously left-footed. So it was interesting to observe them primarily use their powerful beaks to pull onion grass plants from the ground and dig up corms, using their left foot only occasionally to manipulate the plant.


Read more: These historic grasslands are becoming a weed-choked waste. It could be one of the world’s great parks


The cockatoos fed for between 30 minutes and two and a half hours. At each feed, one or two sentry (or sentinel) birds, depending on the flock size, would keep watch and give raucous warning should danger threaten.

The cockies could remove a plant and corm from the ground in as little as six seconds, but sometimes it could take up to 30 seconds. They then removed and consumed a corm every 14 seconds on average in wet soil and every 18 seconds from harder, dry soil.

Eight cockatoos on grass, with autumn leaves
When flocks feed, one or two sentinel birds keep watch for danger. Shutterstock

This means a flock of 63 birds could remove more than 35,400 onion grass plants in a feeding session lasting two and half hours. This is a super weeding effort by any standard!

Future partnerships

My further investigation revealed most of the corms were within 20 millimetres of the soil surface, so the holes left in the soil by the birds extracting the onion grass were shallow and quite small. This shouldn’t give seeds from onion grass any great advantage.

And they’re very efficient: the birds eat over 87% of the corms they lift, which then won’t get a chance to generate in future years. So, if we’re going to try to eradicate onion grass, it may be better to let the cockies do their work first before we humans take a turn.

We have a lot to learn about how our native species interact with introduced weeds, and more research might reveal some very useful future partnerships. They might be birdbrains, but sulphur-crested cockatoos really know their onions when it comes to, well, onion grass.


Read more: Running out of things to do in isolation? Get back in the garden with these ideas from 4 experts


Gregory Moore, Doctor of Botany, University of Melbourne

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

Life After Truth by Ceridwen Dovey

‘Veritas’

The novel opens with extracts from the ‘Harvard Class of 2003 – Fifteenth Anniversary Report’: the self-penned entries of five close friends introduce the characters we will meet at the fifteen-year anniversary reunion: Jomo, Juliet (Jules), Eloise, Mariam, and Rowan. The chapters that follow provide us with a third person perspective from four of them. Only four? Jules, a famous actress, is very private and her own perspective is not shared. Jomo is a successful gemologist, carrying an engagement ring, but unable to propose to his girlfriend Giselle. Eloise has built a profession on the science of happiness. She is now Professor of Hedonics but struggles with some issues. Her wife, Binx is younger, and has different priorities. Mariam and Rowan married early. Rowan is the principal of a public school in Brooklyn while Mariam is occupied with the ‘daily slog of parenting’. Money is tight for Mariam and Rowan. Rowan wonders if they should have chosen meaning over wealth? And then there is the elephant in the room: the despised Frederick Reese, the disliked son of a disliked American president.

While we learn about each character from their own third person perspectives and their interactions with each other, our perspectives of Jules and Frederick are limited to the observations of others. Everyone is hiding something, each presents an aspect of themselves to the others, but what is truth? Why doesn’t Mariam tell Rowan about her newly found religious beliefs? Why doesn’t Eloise share her ambivalence around surrogacy with Binx? And why is Jomo unable to propose to Giselle? All these questions are overshadowed by the death of Frederick Reese, whose body is found on the last day of the reunion weekend. Truth in death?

I finished this novel hoping that some of the tensions between characters would be resolved, but recognising that life is complicated, that the friction between ambition and achievement is real and that communication is never complete. I am left disquieted about my feeling that the death of Frederick Reese is justified, and I am delighted that I have no wish to make the acquaintance of a  fembot named Elly+.

Jennifer Cameron-Smith

#AWW2021

#AussieAuthor2021

Honeybee by Craig Silvey

‘I wasn’t cold, but I was shivering when I walked onto the Clayton Road overpass.’

Sam Watson is fourteen years old when he climbs over the rail on that overpass and looks down. He cannot see any alternative to a life he cannot bear living. He is not alone: Vic, an elderly man, is standing at the other end of that same overpass. Sam does not want any witnesses, so he waits. Vic is tired and ill and ready to join his wife Edie, who died ten years earlier. But he wants to stop Sam from jumping. An unlikely friendship is struck.

What has led Sam and Vic to this bridge? The story moves between Sam’s past and present. Sam cannot be who he wants to be, and he is caught in an awful home situation. He does not think that his mother needs him anymore, now that his stepfather Steve is in control. Sam stays with Vic, and Vic tells him something of his own life, of his happiness with Edie and of things that have gone wrong. 

‘Edie’s diaries made me realise life was made up of lots of small moments that you could control and a few big ones that you couldn’t.’

Sam and Vic want to help each other but how does a fourteen-year-old learn to trust when years of bullying has caused him to develop such impressive defences against the world? How can Sam be himself when, in the past, he has been ridiculed and punished for being different? While Vic accepts Sam, he is elderly and ill. And not everyone sees their friendship as altruistic.

I became lost in this novel, unable to put it down, afraid to reach the end because I was not sure what would happen. I was pleased when Sam made friends who accepted and helped him, such as Agnes, Peter, and Diane. I liked Vic and I was delighted with his acceptance of Sam but struggled a little with how accepting he was. I finished the novel wishing that every person suffering from gender dysphoria could have a Vic, an Agnes, a Peter, and a Diane in their lives.

This novel contains some difficult themes, including domestic violence, drug abuse, gender dysphoria, and self-harm. Sam felt very real to me, as did most of the other characters.

‘It has nothing to do with you. And I’m not wrong, I’m me. And I don’t want to be invisible anymore.  I want people to see who I am.’

Highly recommended.

Jennifer Cameron-Smith

#AussieAuthor2021

Herd immunity is the end game for the pandemic, but the AstraZeneca vaccine won’t get us there (from The Conversation)

Zoë Hyde, University of Western Australia

In the past fortnight, two vaccine stories made headlines around the world.

Novavax announced spectacular results for its phase 3 trial, while preliminary data suggest the AstraZeneca vaccine is ineffective against the South African variant.

These two vaccines comprise the bulk of Australia’s vaccine portfolio, and the results should prompt an urgent rethink of our vaccination strategy.

Australia won’t reach herd immunity with the current plan.

Australia’s strategy

Australia has secured access to 20 million doses of the Pfizer/BioNTech vaccine, 53.8 million doses of the Oxford/AstraZeneca vaccine, and 51 million doses of the Novavax vaccine. All of these require two doses for maximum effectiveness.

The federal government plans to begin vaccinating groups at high risk with the Pfizer/BioNTech vaccine, then use the AstraZeneca vaccine for the remainder of the population.

The Novavax vaccine may be used at a later date.

But the efficacy of these vaccines is very different

There’s been some confusion over the efficacy of the AstraZeneca vaccine, because of a dosing mistake in one of the early trials. But what’s clear is that its efficacy with a standard, two-dose schedule is 62%.

In comparison, the efficacy of Pfizer/BioNTech’s vaccine is 95%, while interim results suggest the Novavax vaccine has an efficacy of 89%.

These differences matter, because if vaccine efficacy is below a certain level, it’s not possible to achieve herd immunity.

If we don’t achieve herd immunity, Australia could be dealing with outbreaks indefinitely

Herd immunity is the only sustainable, long-term strategy to prevent the virus from spreading throughout the community.

The proportion of the population needing to be vaccinated to achieve herd immunity depends on both how contagious a disease is, and how effective the vaccines for it are. It can be calculated by a simple formula, the results of which are shown in the graph below.

Proportion of the population that would need to be vaccinated to achieve herd immunity. Author provided

The contagiousness of the virus which causes COVID-19, given by its basic reproduction number (R₀), is thought to be around 2.5. That means, on average, a person with COVID-19 will infect 2.5 people. Of course, some people infect nobody, while others infect many more in super-spreading events.

We’d need to vaccinate almost everyone in Australia to achieve herd immunity with the AstraZeneca vaccine, which isn’t feasible.

Some people have medical conditions that prevent vaccination. We also won’t be able to vaccinate children for a while, because vaccines aren’t yet approved for this age group, although trials are underway.

However, we’d perhaps only need to vaccinate 63% of the population with the Pfizer/BioNTech vaccine, or 67% if we used the Novavax vaccine. This is achievable.

Using the planned combination of the Pfizer/BioNTech vaccine and the AstraZeneca vaccine will still require an unfeasibly large proportion of the population to be vaccinated, because children and teenagers make up about one-fifth of Australia’s population.

In practice, we’ll probably need to vaccinate slightly more people than these figures suggest, because vaccines likely protect against symptomatic disease better than they do against any infection. The figures for efficacy quoted above are for symptomatic disease.

But further unpublished results from the ongoing AstraZeneca trials, and data collected during the trial of the Moderna vaccine, suggest efficacy against infection may be reasonably close to that for symptomatic disease.

New variants threaten herd immunity

New viral variants have complicated the picture. They can threaten our ability to achieve herd immunity in two ways. More transmissible variants (with a higher R₀) mean more people will need to be vaccinated.

They can also directly affect vaccine efficacy, which we’ve seen in South Africa.

Preliminary data suggest the AstraZeneca vaccine is unable to prevent mild to moderate disease caused by the South African variant, and the efficacy of the vaccine dropped to 22%.


Read more: UK, South African, Brazilian: a virologist explains each COVID variant and what they mean for the pandemic


South Africa paused the rollout of the AstraZeneca vaccine, and will use the Johnson & Johnson and Pfizer/BioNTech vaccines instead.

The South African variant has also affected the efficacy of the Novavax vaccine, which was reduced to 60%. We don’t yet know how the variant might affect the efficacy of the Pfizer/BioNTech vaccine, but some reduction is likely.

What does this mean for Australia?

Australia is in an incredibly fortunate position, with almost no community transmission. Breaches in the hotel quarantine system are now the major source of outbreaks in Australia.

An increasing proportion of cases in Australian hotel quarantine are infected with variants. At least 18 cases of the South African variant have been detected so far.

Variants of concern are becoming dominant globally. These are what our vaccination strategy must prevent. AstraZeneca’s vaccine won’t protect us against the South African variant, but high-efficacy vaccines like those made by Novavax and Pfizer/BioNTech probably still will.

If Australia rolled out the AstraZeneca vaccine, we’d be starting behind the eight ball, and we’d have to do a second rollout to protect everyone against the South African variant.

But vaccination is going to be a mammoth task. To meet the government’s target of vaccinating all adults by October, Australia will need to vaccinate around 200,000 people per day.

Realistically, we’re only going to get one shot at achieving maximum population coverage, and so it’s critical that we get this right.

Is the AstraZeneca vaccine still useful?

Australia’s Chief Medical Officer, Paul Kelly, argued the AstraZeneca vaccine is still useful because it can prevent death and severe illness 100% of the time.

In reality, that’s not a claim supported by science, because the AstraZeneca trial lacked statistical power to evaluate this endpoint. In fact, only two severe cases occurred during the trial, including one death (both of which were in the placebo group).

We’d need a much larger trial to understand how well the AstraZeneca vaccine prevents severe disease. This would provide the larger number of events needed to distinguish a significant difference between the placebo and vaccine group.

However, we can expect COVID-19 vaccines to be better at preventing serious outcomes than mild ones, and so the AstraZeneca vaccine might still do quite well against severe disease.

But we don’t yet know what the efficacy will be, and death isn’t the only outcome to consider. Vaccines must also be able to prevent the debilitating condition known as “long COVID”, which is relatively common, even in people who initially had mild COVID-19.

The Office for National Statistics in the UK estimates that 1 in 10 people experience persistent symptoms lasting at least 12 weeks.

The AstraZeneca vaccine will still be very useful for countries battling second waves caused by the original strain of the virus. In this context, the vaccine will save lives.

It’s also very important to note that no safety concerns have been identified with the AstraZeneca vaccine.

Australia should go for herd immunity

With no widespread community transmission, Australia can afford to prioritise a long-term herd immunity strategy, rather than focusing on a short-term goal of saving lives.

In addition to expected overseas supplies of the Pfizer/BioNTech vaccine, Australia has the capacity to manufacture the high-efficacy Novavax vaccine domestically.

Unlike the Pfizer/BioNTech vaccine, the Novavax vaccine can be kept in a refrigerator, making it ideal for use in urban, rural, and remote Australia.

Australia must not squander this opportunity by proceeding with the rollout of a vaccine that’s already been proven ineffective against one of the world’s most concerning variants. Rather, we must use high-efficacy vaccines to build herd immunity, and secure Australia’s long-term future.

Zoë Hyde, Epidemiologist, University of Western Australia

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

Historic Tasmania Sketchbook by Patsy Adam Smith and Joan Woodberry (text) Max Angus, Frank Mather and Arthur Phillips (drawings)

‘There is only one reason for Tasmania retaining so many splendid buildings: they have been lived in by people who appreciate them and are determined to preserve them.’

I have a copy of the 1977 edition of this book. Whenever I get homesick for Tasmania, I browse through the sketches and reacquaint myself with some of the magnificent nineteenth buildings I recognise. But it isn’t just sketches of buildings contained in this book, there’s a sketch of Kelly’s Steps between Salamanca Place and Battery Point, and of the iron hull of the ‘Otago’ (remember Joseph Conrad?) on the east bank of the Derwent.

I am pleased I was able to visit the Church of St John the Baptist (consecrated in 1850) last time I was in Buckland (page 58). And the Morris Store building (now housing the everyday IGA) in Swansea (page 54) is superb.

While some buildings are in private hands, others are part of the National Trust including Franklin House (Launceston); Entally (Hadspen)and Clarendon (Evandale). And a visit to Richmond would not be complete without walking through the historic village, over the bridge and up to St John’s Church in Richmond (built in 1836).

On each page, there is a reminder of Tasmania’s colonial past: from the prosperous estates and mansions owned by the wealthy to the buildings of Port Arthur associated with convict transportation. I walk along St John Street in Launceston, past St John’s Church (page 186) where my grandparents were married in 1918, past the Dorset Terrace (page 164) where I’d love to live.  Launceston also has many beautiful civic buildings, built during its prosperous past: the Albert Hall (page 150) (where I sat examinations during the early 1970s); the Town Hall (page 168) and the Custom House (page174).

The book is divided into four parts:

Nineteenth Century Tasmania

Hobart

Launceston

Port Arthur

Superb sketches by Max Angus, Frank Mather and Arthur Phillips are accompanied by text by Patsy Adam Smith and Joan Woodberry.

If you are interested in Tasmania’s colonial past, this book (if you can find a copy) is worth exploring.

Jennifer Cameron-Smith

#AWW2021

#AussieAuthor2021

Factory 19 by Dennis Glover

‘Workers of the world unite. You have nothing to lose but your smartphones.’

Hobart, 2022. A city in recession, the future looks grim.  And then, one day, a rusty ship sails down the Derwent River to the site of the once famous, but now abandoned Gallery of Future Art, known as GoFA.

What on earth is going on?

Our narrator is Paul Richey:

‘I was the first confirmed case of something called ‘digital proximity anxiety’ – DPA – which the media inevitably dubbed ‘smartphone shock’.

Paul lived on Bruny Island in a low technology environment, to recover from a breakdown brought on by the relentless pressure of the 24/7 media cycle working for the unreasonable and demanding Prime Minister X. Eventually, he recovers well enough to move to Hobart. Paul tells us about the brave new world established by Dundas Faussett (D.F. as he is known), a world in which the future holds the past. D.F. founded the now abandoned GoFA and returns to Hobart to transform the site into a 1948 factory.

‘I contemplated my situation. I’d woken up in 2024 and was now about to go to bed in 1948.’

Yes, 1948. Specifically, March 1948, before the first commercial mainframe computer and the establishment of the RAND Corporation. Before the internet, before smartphones, before Amazon.  A world in which factories had production lines with people making things. Everyone has a job: making goods from 1948, using the materials available at the time. Measurements are imperial (again) and the men use Brylcreem.  My parents and grandparents would have been right at home.

‘Ladies and gentlemen, welcome to Factory 19. The sort of world you used to live in.’

But the transition back to the past might not be as easy as D.F. envisages. Not everyone wants to give up 21st century technology, and the success of the factory, with its growing export markets, brings a different set of problems.

‘It was one thing to re-create the past, but another altogether to get it to work efficiently.’

This is a brilliant novel, and I thoroughly enjoyed the way in which Mr Glover recreates the past, makes us nostalgic for what seem to be happier days (even those of us who were not born until after 1948). He reminds us that while the present is not always superior to the past, some aspects are not so easily jettisoned.

How does it end? You will need to read it to find out.

‘Remembering is the most powerful political act of all.’

Jennifer Cameron-Smith

#AussieAuthor2021

The Good Girls: An Ordinary Killing by Sonia Faleiro

‘People called them Padma Lalli like they were one person.’

On 27 May 2014, in the village of Katra Sadatgani in Uttar Pradesh, India, two teenaged girls went into the fields to relieve themselves before bed. They did not return. In the early hours of the following morning, their bodies were found hanging from a mango tree in the orchard tended by their families. Their bodies were to remain in that tree for some time.

We know those two girls as sixteen-year-old Padma* and fourteen-year-old Lalli*. They were cousins and best friends. *We do not know their real names as there is an Indian law which requires that the identity of the victims of certain crimes is kept private. The irony: a law which affords victims more privacy in death than they were ever accorded in life.

In this book, Ms Faleiro draws on official documents, interviews, and news reports to try to establish a timeline of events within the context of the environment in which the girls lived.  Ms Faleiro describes the physical setting: a poor village, with no running water or sanitation (which is why the girls had to relieve themselves in the field); a rigid family structure, shaped by caste, custom and religion; and mistrust of (often corrupt) authorities.

This is a confronting and uncomfortable read. The girls are left hanging in the mango tree because their families believe that this is necessary in order to obtain justice.  And once the girls are removed from the tree, inept handling and forensic processes mean mistakes are made, and erroneous conclusions are reached. Contradictory information is given by those interviewed; assumptions are made. The death of the girls is devastating for those left behind. But at every step the investigation is hampered. Honour becomes more important than truth.

What really happened to Padma and Lalli? I doubt that we will ever know.

In writing about this case, Ms Faleiro illustrates the complexity of life in India, the prevalence of crimes against women, the impact of tradition, and how mistrust shapes both investigation and witness accounts.

I finished this book wondering whether the situation has improved since Padma and Lalli died. This is not an easy book to read both because of the content and the amount of detail provided. The detail is necessary but can feel overwhelming.

‘Finally, while this is a story about the marginalisation and subjugation of women in India, it is also about what it means to be poor.’

Note: My thanks to NetGalley and Grove Press for providing me with a free electronic copy of this book for review purposes. 

Jennifer Cameron-Smith

Trust (Martin Scarsden #3) by Chris Hammer

‘I think it’s coming for us.’

Martin Scarsden, journalist and true crime writer, his girlfriend Mandalay (‘Mandy’) Blonde and her son Liam are settling into life at Port Silver (where Martin Scarsden #2 ended). Martin and Liam are on the beach. He picks up his phone: there is a voicemail from Mandy, a single scream. He rushes home. Mandy is missing, a man left unconscious on the floor.

Mandy has been drugged and abducted. Why, and by whom?

The answer rests in Mandy’s past, a past that she has not shared with Martin, a past she thought was far behind her. The answer is in Sydney.

‘Fewer know of its existence, fewer still know of its power.’

This is a fast-moving story which digs into Mandy’s past, into her relationship with a man who apparently stole millions from an investment bank and fled. But when his body is found in the foundations of a building, his involvement in the theft needs to be re-examined. Martin is asked to join his old editor, Max Fuller, in an investigation. But Max is killed, as is Elizabeth Torbett, a supreme court justice. Is it a murder-suicide? Martin wants answers.

Can Mandy trust Martin enough to tell him about the past? Can Martin find out what happened to Max Fuller and Elizabeth Torbett? There is plenty of suspense in this novel especially when Mandy and Martin join forces. Mr Hammer has peopled this novel with a fine mixture of characters: the good, the bad and the ugly. If you enjoy action filled novels, in a series where the main characters continue to develop, then I can recommend this.

Jennifer Cameron-Smith

#AussieAuthor2021

Nationals’ push to carve farming from a net-zero target is misguided and dangerous (from The Conversation)

Shutterstock

Rachelle Meyer, University of Melbourne

Prime Minister Scott Morrison might be warming to the goal of net-zero emissions by 2050, but federal Nationals leader Michael McCormack has thrown a spanner in the works by suggesting agriculture be excluded from the target.

On Sunday, McCormack told Sky News the Coalition government will not “whack regional Australia” just to meet a climate target. He went on:

There is no way we are going to […] hurt regional Australia, in any way shape or form just to get a target for climate in 2050. We are not going to hurt those wonderful people that put food on our table.

But the Nationals’ push is deeply misguided. It dumps the burden of emissions reduction on other sectors, and puts Australian farmers and the broader economy at greater risk of climate change damage.

Michael McCormack eating a piece of fruit
Nationals leader Michael McCormack wants farming exempted from emissions targets. Daniel Mariuz/AAP

Farming emissions: a sobering picture

Most emissions from the farming sector come in the form of methane and nitrous oxide.

Livestock such as cattle and sheep produce methane when they digest plant material. This gas makes up about 70% of Australia’s agricultural emissions.

Nitrous oxide is released from nutrient-rich soils, such as soils where fertilisers have been applied or when livestock deposit urine and manure on the ground.

In 2019, agriculture produced almost 13% of Australia’s national emissions, or 69 million tonnes. Land clearing for agriculture also drives deforestation in Australia, which is responsible for about 30 million tonnes of greenhouse gases a year. Combined, the emissions comprised about 18% of annual emissions in 2019 – equal to the transport sector.


Read more: Australia’s farmers want more climate action – and they’re starting in their own (huge) backyards


What’s more, agricultural emissions are projected to increase over the next decade. It’s estimated by 2030, the sector (excluding land clearing) will emit between 78 and 112 million tonnes of greenhouse gases each year. By 2050, that figure could reach 132.5 million tonnes, according to advice prepared for the federal government in 2013.

A report released last week by the expert Climate Targets Panel found Australia’s emissions must be slashed by 50% or more by 2030 to reach net-zero emissions by 2050. Australia must meet this target to be consistent with the international goal of keeping global warming below 2°C.

Granting an exemption to agriculture may well mean Australia would miss the 2050 target. At the very least, it would place an unfair burden on other industries to pick up the slack.

Farm meets forest
Forests, which reduce carbon in the atmosphere, are cleared for agriculture. Shutterstock

A challenging task

No-one says reducing emissions from the agriculture sector will be easy. In contrast to, say, the electricity sector, where low-carbon technology (in the form of renewable energy) is already widely deployed, such technologies in farming are largely still immature or involve complicating factors.

For example, chemical inhibitors can be applied to soil to reduce the production of nitrous oxide. However, inhibitors vary in effectiveness and the reasons behind this are not well understood.

Alternatively, legume crops increase nitrogen in the soil, and including them in rotations can mean less fertiliser is needed. But if planting legumes means other additional crops are planted elsewhere, this may lead to indirect emissions.

Feed additives given to livestock are a promising way to reduce methane emissions. For example 3-NOP, a chemical pellet mixed into animal feed, has been shown to slash methane emissions from Australian farms. However, 3-NOP is not yet been approved for use in Australia and the price may yet prove prohibitive.

Also, most of the agriculture sector’s methane emissions come from large farms where graziers don’t often directly feed or interact with livestock. That means feed additives and similar options are not practical in these systems.

Diagram showing the global carbon and nitrogen cycles and their interaction with land use.
Diagram showing the global carbon and nitrogen cycles and their interaction with land use. https://www.pce.parliament.nz/media/196523/report-farms-forests-and-fossil-fuels.pdf

Emissions from farms, returned to the land

So while the above options are being ironed out, what’s the best way to cut emissions from agriculture? Research I published last year proposed one solution: pairing agriculture emissions with forestry “sinks” – an area of trees and soil that sucks up carbon dioxide.

In a neat synergy, methane and nitrous oxide last in the atmosphere for about the same times as carbon is stored in land sinks, such as trees and soil. So it makes sense to use land sinks to offset agriculture emissions.


Read more: Climate Change Commission calls on New Zealand government to take ‘immediate and decisive action’ to cut emissions


Carbon dioxide, such as that emitted from power plants, lasts longer in the atmosphere than farming emissions. It’s best dealt with by decarbonising the electricity and transport sectors, rather than offsetting with biological sinks.

So farmers could, for example, offset their emissions by planting forests. This would enable them to start meeting a net-zero target while new methods for emissions reduction are developed and brought to market.

Research has shown the land sector could potentially achieve net-zero emissions by 2030, using carbon sinks and a mass reduction in land clearing.

Shrubs in buckets.
Planting trees can offest emissions by farmers. Shutterstock

A clear way forward

Reducing the footprint of Australia’s agriculture sector is no simple feat. It will require:

  • substantial investment to address research gaps
  • incentives for farmers to adopt commercially viable mitigation options, such as anaerobic digestors to turn animal waste in intensive systems into energy
  • incentives for farmers to adopt options that are not commercially viable. This might mean reducing stock numbers when necessary, to restore degraded pastures which increases soil carbon stocks.

Australia’s agriculture is extremely vulnerable to the effects of climate change: bushfires and extreme weather, as well as changes to rainfall, temperature, soils, water, pests and diseases.

Farming should not be exempt from a net-zero target. Not only would this make the job of climate action harder for other parts of the economy, it will ultimately come back to bite farmers themselves.


Read more: Biden’s Senate majority doesn’t just super-charge US climate action, it blazes a trail for Australia


Rachelle Meyer, Postdoctoral Fellow (Farm Systems Analysis), University of Melbourne

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

The Widows of Broome (Inspector Napoleon Bonaparte #13) by Arthur W. Upfield

‘Situated on the barren, inhospitable coast of the north-west of Australia, Broome’s only excuse for existence is pearl shell.’

Detective-Inspector Bonaparte (Bony) arrives in Broome after two well-to-do widows are murdered by strangulation. The murderer has apparently left no clues, the local police are shorthanded, and the town is on edge. Bony, posing as a visiting psychiatrist, has barely started his investigation when a third widow is murdered. But this time, the murderer may have been careless. Bony, with the help of Mr Dickenson, a colourful local character, starts to form a picture of the murderer. He is aided by footprints, three bundles of silk rags, and the sound of clicking teeth.

Time is running out: can Bony protect the remaining widows of Broome?

I enjoyed this clever, well-written murder mystery. I vaguely remember the Boney television series which ran for two seasons in the early 1970s. My mother was a big fan and read each of the novels. This is the first novel I have read, and I will look out for the others. Given the age of the novel, it is worth including this editorial note:

‘Part of the appeal of Arthur Upfield’s stories lies in their authentic portrayal of many aspects of outback Australian life in the 1930s and through into the 1950s. The dialogue, especially, is a faithful evocation of how people spoke. Hence, these books reflect and depict the attitudes and ways of speech, particularly with regard to Aborigines and to women, which were then commonplace.  In reprinting these books the publisher does not endorse the attitudes or opinions they express.’

Jennifer Cameron-Smith

#AussieAuthor2021