Tasmania’s salmon industry detonates underwater bombs to scare away seals – but at what cost?


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Benjamin J. Richardson, University of TasmaniaAustralians consume a lot of salmon – much of it farmed in Tasmania. But as Richard Flanagan’s new book Toxic shows, concern about the industry’s environmental damage is growing.

With the industry set to double in size by 2030, one dubious industry practice should be intensely scrutinised – the use of so-called “cracker bombs” or seal bombs.

The A$1 billion industry uses the technique to deter seals and protect fish farming operations. Cracker bombs are underwater explosive devices that emit sharp, extremely loud noise impulses. Combined, Tasmania’s three major salmon farm operators have detonated at least 77,000 crackers since 2018.

The industry says the deterrent is necessary, but international research shows the devices pose a significant threat to some marine life. Unless the salmon industry is more strictly controlled, native species will likely be killed or injured as the industry expands.

pile of grey and white fish
Tasmanian salmon farming is a billion-dollar industry.
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Protecting a lucrative industry

Marine farming has been growing rapidly in Tasmania since the 1990s, and Atlantic salmon is Tasmania’s most lucrative fishery‑related industry. The salmon industry comprises three major producers: Huon Aquaculture, Tassal and Petuna.

These companies go to great effort to protect their operations from fur seals, which are protected in Australia with an exemption for the salmon industry.

Seals may attack fish pens in search of food and injure salmon farm divers, though known incidents of harm to divers are extremely rare.

The industry uses a number of seal deterrent devices, the use of which is approved by the government. They include:

  • lead-filled projectiles known as “beanbags”, which are fired from a gun
  • sedation darts fired from a gun
  • explosive charges or “crackers” thrown into the water which detonate under the surface.

In June this year, the ABC reported on government documents showing the three major salmon producers had detonated more than 77,000 crackers since 2018. The documents showed how various seal deterrent methods had led to maiming, death and seal injuries resulting in euthanasia. Blunt-force trauma was a factor in half the reported seal deaths.

A response to this article by the salmon industry can be found below. The industry has previoulsy defended the use of cracker bombs, saying it has a responsibility to protect workers. It says the increased use of seal-proof infrastructure means the use of seal deterrents is declining. If this is true, it’s not yet strongly reflected in the data.




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Here’s the seafood Australians eat (and what we should be eating)


salmon farm infrastructure in water
Seal deterrents are deployed to protect salmon farm operations.
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Piercing the ocean silence

Given the prevalence of seal bomb use by the salmon industry, it’s worth reviewing the evidence on how they affect seals and other marine life.

A study on the use of the devices in California showed they can cause horrific injuries to seals. The damage includes trauma to bones, soft tissue burns and prolapsed eye balls, as well as death.

And research suggests damage to marine life extends far beyond seals. For example, the devices can disturb porpoises which rely on echolocation to find food, avoid predators and navigate the ocean. Porpoises emit clicks and squeaks – sound which travels through the water and bounces off objects. In 2018, a study found seal bombs could disturb harbour porpoises in California at least 64 kilometres from the detonation site.

There is also a body of research showing how similar types of industrial noise affect marine life. A study in South Africa in 2017 showed how during seismic surveys in search of oil or gas, which produce intense ocean noise, penguins raising chicks often avoided their preferred foraging areas. Whales and fish have also shown similar avoidance behaviour.

The study showed underwater blasts can also kill and injure seabirds such as penguins. And there may be implications from leaving penguin nests unattended and vulnerable to predators, and leaving chicks hungry longer.

Research also shows underwater explosions damage to fish. One study on caged fish reported profound trauma to their ears, including blistering, holes and other damage. Another study cited official reports of dead fish in the vicinity of seal bomb explosions.




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dolphin jumps out of waves
Man-made noise can disturb a variety of marine animals, including porpoises.
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Shining a light

Clearly, more scientific research is needed into how seal bombs affect marine life in the oceans off Tasmania. And regulators should impose far stricter limits on the salmon industry’s use of seal bombs – a call echoed by Tasmania’s Salmon Reform Alliance.

All this is unfolding as federal environment laws fail to protect Australian plant and animal species, including marine wildlife.

And the laws in Tasmania are far from perfect. In 2017, Tasmania’s Finfish Farming Environmental Regulation Act introduced opportunities for better oversight of commercial fisheries. However, as the Environmental Defenders Office (EDO) has noted, the director of Tasmania’s Environment Protection Authority can decide on license applications by salmon farms without the development necessarily undergoing a full environmental assessment.

Tasmania’s Marine Farming Planning Act covers salmon farm locations and leases. As the EDO has noted, the public is not notified of some key decisions under the law and has very limited public rights of appeal.

Two relevant public inquiries are underway – a federal inquiry into aquaculture expansion and a Tasmanian parliamentary probe into fin-fish sustainability. Both have heard evidence from community stakeholders, such as the Tasmanian Alliance for Marine Protection and the Tasmanian Conservation Trust, that the Tasmanian salmon industry lacks transparency and provides insufficient opportunities for public input into environmental governance.

The Tasmanian government has thrown its support behind rapid expansion of the salmon industry. But it’s essential that the industry is more tightly regulated, and far more accountable for any environmental damage it creates.




Read more:
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In a statement in response to this article, the Tasmanian Salmonid Growers Association, which represents the three producers named above, said:

Around $500 million has been spent on innovative pens by the industry. These pens are designed to minimise risks to wildlife as well as to fish stocks and the employees. We believe that farms should be designed to minimise the threat of seals, but we also understand that non-lethal deterrents are a part of the measures approved by the government for the individual member companies to use. If these deterrents are used it is under strict guidelines, sparingly, and in emergency situations when staff are threatened by these animals, which can be very aggressive.

Tasmania has a strong, highly regulated, longstanding salmon industry of which we should all be proud. The salmon industry will continue its track record of operating at world’s best practice now and into future. Our local people have been working in regional communities for more than 30 years, to bring healthy, nutritious salmon to Australian dinner plates, through innovation and determination.The Conversation

Benjamin J. Richardson, Professor of Environmental Law, University of Tasmania

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

The clock is ticking on net-zero, and Australia’s farmers must not get a free pass


Dan Peled/AAP

James Ha, Grattan InstitutePolitical momentum is growing in Australia to cut greenhouse gas emissions to net-zero by 2050. On Friday, Treasurer Josh Frydenberg was the latest member of the federal government to throw his weight behind the goal, and over the weekend, Prime Minister Scott Morrison acknowledged “the world is transitioning to a new energy economy”.

But for Australia to achieve net-zero across the economy, emissions from agriculture must fall dramatically. Agriculture contributed about 15% to Australia’s greenhouse gas emissions in 2019 – most of it from cattle and sheep. If herd numbers recover from the recent drought, the sector’s emissions are projected to rise.

Cutting agriculture emissions will not be easy. The difficulties have reportedly triggered concern in the Nationals’ about the cost of the transition for farmers, including calls for agriculture to be carved out of any net-zero target.

But as our new Grattan Institute report today makes clear, agriculture must not be granted this exemption. Instead, the federal government should do more to encourage farmers to adopt low-emissions technologies and practices – some of which can be deployed now.




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four people walk through dusty farm
The Morrison government must do more to help farmers get on the path to net-zero.
Alex Ellinghausen AAP/Fairfax Media pool

Three good reasons farmers must go net-zero

Many farmers want to be part of the climate solution – and must be – for three main reasons.

First, the agriculture sector is uniquely vulnerable to a changing climate. Already, changes in rainfall have cut profits across the sector by 23% compared to what could have been achieved in pre-2000 conditions. The effect is even worse for cropping farmers.

Livestock farmers face risks, too. If global warming reaches 3℃, livestock in northern Australia are expected to suffer heat stress almost daily.

Second, parts of the sector are highly exposed to international markets – for example, about three-quarters of Australia’s red meat is exported.

There are fears Australian producers may face a border tax in some markets if they don’t cut emissions.
The European Union, for instance, plans to introduce tariffs as early as 2023 on some products from countries without effective carbon pricing, though agriculture will not be included initially.

Third, the industry recognises action on climate change can often boost farm productivity, or help farmers secure resilient revenue streams. For example, trees provide shade for animals, while good soil management can preserve the land’s fertility. Both activities can store carbon and may generate carbon credits.

Carbon credits can be used to offset farm emissions, or sold to other emitters. In a net-zero future, farmers can maximise their carbon credit revenue by minimising their own emissions, leaving them more carbon credits to sell.

The agriculture sector itself is increasingly embracing the net-zero goal. The National Farmers Federation supports an economy-wide aspiration to be net-zero by 2050, with some conditions. The red meat and pork industries have gone further, committing to be carbon neutral by 2030 and 2025 respectively.




Read more:
Land of opportunity: more sustainable Australian farming would protect our lucrative exports (and the planet)


hand presses soil
Good soil management aids a farm’s fertility.
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What can be done?

Australian agricultural activities emitted about 76 million tonnes of carbon dioxide-equivalent emissions in 2019. Of this, about 48 million tonnes were methane belched by cattle and sheep, and a further 11 million came from their excrement.

The sector’s non-animal emissions largely came from burning diesel, the use of fertiliser, and the breakdown of leftover plant material from cropping.

Unlike in, say, the electricity sector, it’s not possible to completely eliminate agricultural emissions, and deep emissions cuts look difficult in the near term. That’s because methane produced in the stomachs of cattle and sheep represents more than 60% of agricultural emissions; these cannot be captured, or eliminated through renewable energy technology.

Supplements added to stock feed – which reduce the amount of methane the animal produces – are the most promising options to reduce agricultural emissions. These supplements include red algae and the chemical 3-nitrooxypropanol, both of which may cut methane by up to 90% if used consistently at the right dose.

But it’s difficult to distribute these feed supplements to Australian grazing cattle and sheep every day. At any given time, only about 4% of Australia’s cattle are in feedlots where their diet can be easily controlled.

Diesel use can be reduced by electrifying farm machinery, but electric models are not yet widely available or affordable for all purposes.

These challenges slow the realistic rate at which the sector can cut emissions. Yet there are things that can be done today.

Many manure emissions can be avoided through smarter management. For example, on intensive livestock farms, manure is often stored in ponds where it releases methane. This methane can be captured and burnt, emitting the weaker greenhouse gas, carbon dioxide, instead.

And better targeted fertiliser use is a clear win-win – it would save farmers money and reduce emissions of nitrous oxide, a potent greenhouse gas.

sheep in lots
Supplements added to stock feed are a promising way to cut emissions.
Dean Lewins/AAP

Governments must walk and chew gum

An economy-wide carbon price would be the best way for Australia to reduce emissions in an economically efficient manner. But the political reality is that carbon pricing is out of reach, at least for now. So Australia should pursue sector-specific policies – including in agriculture.

Governments must walk and chew gum. That means introducing policies to support emissions-reducing actions that farmers can take today, while investing alongside the industry in potential high-impact solutions for the longer term.

Accelerating near-term action will require improving the federal government’s Emissions Reduction Fund, to help more farmers generate Australian carbon credit units. It will also require more investment in outreach programs to give farmers the knowledge they need to reduce emissions.

Improving the long-term emissions outlook for the agriculture sector requires investment in high-impact research, development and deployment. Bringing down the cost of new technologies is possible with deployment at scale: all governments should consider what combination of subsidies, penalties and regulations will best drive this.

Agriculture must not become the missing piece in Australia’s net-zero puzzle. Without action today, the sector may become Australia’s largest source of emissions in coming decades. This would require hugely expensive carbon offsetting – paid for by taxpayers, consumers and farmers themselves.




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The Conversation


James Ha, Associate, Grattan Institute

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

Climate change means Australia may have to abandon much of its farming


Andrew Wait, University of Sydney and Kieron Meagher, Australian National UniversityThe findings of the Intergovernmental Panel on Climate Change suggest Australia may have to jettison tracts of the bush unless there is a massive investment in climate-change adaptation and planning.

The potential impacts of climate change on employment and the livability of the regions have not been adequately considered. Even if emissions are curtailed, Australia likely faces billions of dollars of adaptation costs for rural communities.

As the IPCC’s Sixth Assessment Report (published last month) makes clear, the climate will change regardless of any mitigation actions taken now.

Even under its modest conservative projections, worldwide temperatures will rise by 1.5℃. That may not sound like much, but it will double the frequency of droughts — from once every 10 years to once every five.

Worse still, a 2℃ temperature rise — also a likely outcome without substantial emission reductions — will make droughts 2.5 times more frequent.




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Farm profits are falling

Climate change is already hurting Australian farmers. Compared with historical averages, agricultural profits have fallen 23% over the 20 years to 2020. This trend will continue.

The Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES) predicts a likely scenario is that overall farm profit will fall by 13% by 2050. There will be significant differences between regions. Cropping profits in Western Australia, for example, are predicted to drop 32%.


Effect of 2001-2020 seasonal conditions on farm profit


ABARES

With higher emissions, the reductions will be worse. Estimates of the fall in farm profits range from 11% to 50%.

These changes go beyond the cycles of weather with which Australian farmers have always had to cope. Inconsistent water supplies, increased natural disasters and greater production risks will render agricultural production in many areas uneconomic.

Due to these climatic changes agricultural assets, both land and infrastructure, could become virtually worthless – so-called stranded assets.

No future without water

Vibrant regional communities aren’t just about farms. They are interdependent networks of businesses, towns, public infrastructure and people.

The effect of falls in farm income will ripple throughout these communities. Lower output will mean fewer jobs. If farms close, so will other regional businesses, leading to more stranded assets. Those affected could face displacement along with an inability to sell their homes and businesses.

And of course these communities can’t survive without water.

So far development planning in Australia has not adequately considered the potential impacts of the climate on livability, especially in rural communities.
This failure to account for climate change exacerbates the potential for stranded assets.

For example, the NSW Auditor General reported in September 2020 that the state government had “not effectively supported or overseen town water infrastructure planning in regional NSW since at least 2014”. This contributed during the intense drought of 2019 to at least ten regional NSW cities or towns coming close to “zero” water.




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Population pressures

In some areas these water problems are being compounded by population growth.

Consider, for instance, the NSW townships surrounding Canberra. In January 2020 the town of Braidwood (about halfway between Canberra and Batemans Bay) had to start trucking in water when its own water source, the Shoalhaven river, stopped flowing. Yet nearby Bungedore (about 50 km away) is building a new high school due to population growth.

This “tree-change” trend, with people leaving cities in search of a better lifestyle and more affordable housing, is widespread. It appears to have been amplified by the COVID-19 pandemic, with figures showing net internal migration of people out of Sydney and Melbourne.

More investment in adaptation needed

There is an urgent need for a comprehensive assessment by all levels of government of risks to livelihoods in agriculture and regional communities, and of the default risk on stranded assets.

Budget projections need to account for climate-change adaptation and economic structural change.

In last year’s budget the federal government committed to investing A$20 billion “to ensure Australia is leading the way in the adoption of new low-emissions technologies while supporting jobs and strengthening our economy”.

As important as this is, we must start planning and spending on adaptation.




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Australian farmers are adapting well to climate change, but there’s work ahead


The A$1.2 billion over five years the federal budget allocated for natural disasters is just the beginning. In some regions changed farming practices, subsidised insurance and investment in water infrastructure may be enough. But proper infrastructure takes many years to plan, and to build.

Some areas are going to become unviable. We will need deal with the loss of entire communities, and internal climate refugees.

It is time to start budgeting for the costs of living with climate change, not just the costs of cutting emissions.The Conversation

Andrew Wait, Professor, University of Sydney and Kieron Meagher, Professor, Research School of Economics, Australian National University

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

Australian farmers are adapting well to climate change, but there’s work ahead


PETER LORIMER/AAP

Neal Hughes, Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES)Australian farmers have proven their resilience, rebounding from drought and withstanding a global pandemic to produce record-breaking output in 2020-21.

But while the pain of drought is fading from view for some, the challenge of a changing climate continues to loom large.

Farmers have endured a poor run of conditions over the last 20 years, including a reduction in average rainfall (particularly in southern Australia during the winter cropping season) and general increases in temperature.

While these trends relate to climate change, uncertainty remains over how they will develop, particularly over how much rain or drought farmers will face.

Research published today by the Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES) examines the effects of past and potential future changes in climate, and sets out how productivity gains to date have been helping farmers adapt to the drier and hotter conditions.

Conditions have been tough

The research examines the effect on farms of climate conditions over the past 20 years, compared to the preceding 50 years.

Holding other factors constant (including commodity prices and technology) ABARES estimates the post-2000 shift in conditions reduced farm profits by an average of 23%, or around A$29,000 per farm per year.




Read more:
Climate change since 2000 has cut farm profits 22%


As with past research, these effects have been strongest among cropping farmers in south-eastern and southern-western Australia, with impacts of over 50% observed in some of the most severely affected areas.


Effect of 2001 to 2020 climate conditions on average farm profit

Simulated broadacre farm profit with current (2015–16 to 2018–19) farms and commodity prices and recent (2000–01 to 2019–20) climate conditions. Interpolated farm-level percentage changes relative to 1949–50 to 1999–2000 climate.
ABARES farmpredict model (Hughes, Lu et al. 2021)

Farmers have been adapting

While these changes in conditions have been dramatic, farmers’ adaptation has been equally impressive.

After controlling for climate, farm productivity (the output from a given amount of land and other inputs) has climbed around 28% since 1989, with a much larger 68% gain in the cropping sector.

These gains have offset the adverse climate conditions and along with increases in commodity prices have allowed farmers to maintain and even increase average production and profit levels over the last decade.

While productivity growth in agriculture is nothing new, the recent gains have been especially focused on adapting to drier and hotter conditions.

Within the cropping sector, for example, a range of new technologies and practices have emerged to better utilise soil moisture to cope with lower rainfall.

As a result, Australian farmers have produced remarkable harvests making use of limited rain, particularly in Western Australia.

Adaptation has also involved movement of traditional Australian cropping zones, increasing cropping in higher rainfall coastal areas, and reducing cropping in marginal in-land areas.

Climate change could make conditions tougher

While climate models generally project a hotter and drier future, a wide range of outcomes are possible, particularly for rainfall.

Climate projections suggest that nationally farmers could experience reductions in average winter season rainfall of 3% to 30% by 2050 (compared to 1950-2000).

The study simulates the effect of future climate change scenarios with current farm technology and no further productivity gains.

As such, these scenarios are not a prediction, but an indication of which regions and sectors might be under the greatest pressure to adapt.

For example, under most scenarios cropping farmers in Western Australia will face more pressure than those in eastern Australia.

Livestock farms will also face more pressure under high emissions scenarios as they are especially impacted by higher temperatures.

Generally, inland low-rainfall farming areas are expected to face greater challenges than regions closer to the coast.


Simulated change in farm profits relative to historical (1950 to 2000) climate

Change in simulated average farm profit for broadacre farms, assuming current commodity prices (2015–16 to 2018–19), and current farm technology (no adaptation), relative to historical climate conditions (1949–50 to 1999–2000). Bars show minimum, maximum and average across the GCMs for each scenario.
Source: ABARES farmpredict model (Hughes, Lu et al. 2021)

There is more work ahead

Recent experience shows that productivity growth can help offset the impact of a changing climate.

However, there remains uncertainty over how far technology can push farm efficiency beyond current levels.

Further, even if technology can offset climate impacts, other exporting nations could still become more competitive relative to Australia, if they are less affected by climate change or can adapt faster.

Here, investment in research and development remains crucial, including efforts to improve the productivity and reduce the carbon footprint of existing crop and livestock systems, along with research into more transformational responses to help diversify farm incomes.

Farmland can be repurposed.
Mick Tsikas

This could include for example, carbon and biodiversity farming, plantation forestry and the use of land to produce renewable energy.

Carbon and biodiversity farming schemes are the subject of ongoing research and policy trials, and already we have seen farmers generate significant revenue from carbon farming.

Uncertainty over the future climate, especially rainfall, remains a key constraint on adaptation. Efforts to refine and better communicate climate information through initiatives such as Climate Services for Agriculture could help farmers and governments make more informed decisions.

While the future is still highly uncertain, the challenge of adapting to climate change is here and now.

Significant resources have been committed in this area, including the Australian government’s Future Drought Fund.

We need to make the most of these investments to prepare for whatever the future holds.The Conversation

Neal Hughes, Senior Economist, 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.

More livestock, more carbon dioxide, less ice: the world’s climate change progress since 2019 is (mostly) bad news


Thomas Newsome, University of Sydney; Christopher Wolf, Oregon State University, and William Ripple, Oregon State UniversityBack in 2019, more than 11,000 scientists declared a global climate emergency. They established a comprehensive set of vital signs that impact or reflect the planet’s health, such as forest loss, fossil fuel subsidies, glacier thickness, ocean acidity and surface temperature.

In a new paper published today, we show how these vital signs have changed since the original publication, including through the COVID-19 pandemic. In general, while we’ve seen lots of positive talk and commitments from some governments, our vital signs are mostly not trending in the right direction.

So, let’s look at how things have progressed since 2019, from the growing number of livestock to the meagre influence of the pandemic.

Is it all bad news?

No, thankfully. Fossil fuel divestment and fossil fuel subsidies have improved in record-setting ways, potentially signalling an economic shift to a renewable energy future.

The graph on the left shows an increase in fossil fuel divestment by 1,117 organisations based on data from 350.org, and the graph on the right shows a decrease in subsidies for fossil fuels based on the International Energy Agency subsidies database. The red lines show changes since our original publication in 2019.

However, most of the other vital signs reflect the consequences of the so far unrelenting “business as usual” approach to climate change policy worldwide.

Especially troubling is the unprecedented surge in climate-related disasters since 2019. This includes devastating flash floods in the South Kalimantan province of Indonesia, record heatwaves in the southwestern United States, extraordinary storms in India and, of course, the 2019-2020 megafires in Australia.

In addition, three main greenhouse gases — carbon dioxide, methane and nitrous oxide — set records for atmospheric concentrations in 2020 and again in 2021. In April this year, carbon dioxide concentration reached 416 parts per million, the highest monthly global average concentration ever recorded.

Time series of three climate-related responses. The red lines show changes since our original publication in 2019.

Last year was also the second hottest year in recorded history, with the five hottest years on record all occurring since 2015.

Ruminant livestock — cattle, buffalo, sheep, and goats — now number more than 4 billion, and their total mass is more than that of all humans and wild mammals combined. This is a problem because these animals are responsible for impacting biodiversity, releasing huge amounts of methane emissions, and land continues to be cleared to make room for them.

There are now more than 4 billion livestock on Earth.
Flickr

In better news, recent per capita meat production declined by about 5.7% (2.9 kilograms per person) between 2018 and 2020. But this is likely because of an outbreak of African swine fever in China that reduced the pork supply, and possibly also as one of the impacts of the pandemic.

Tragically, Brazilian Amazon annual forest loss rates increased in both 2019 and 2020. It reached a 12-year high of 1.11 million hectares deforested in 2020.

Ocean acidification is also near an all-time record. Together with heat stress from warming waters, acidification threatens the coral reefs that more than half a billion people depend on for food, tourism dollars and storm surge protection.

Map of land-ocean temperature index anomaly in June, relative to the 1951-1980 baseline.
Oregon State/NASA

What about the pandemic?

With its myriad economic interruptions, the COVID-19 pandemic had the side effect of providing some climate relief, but only of the ephemeral variety.

For example, fossil-fuel consumption has gone down since 2019 as did airline travel levels.

But all of these are expected to significantly rise as the economy reopens. While global gross domestic product dropped by 3.6% in 2020, it is projected to rebound to an all-time high.

So, a major lesson of the pandemic is that even when fossil-fuel consumption and transportation sharply decrease, it’s still insufficient to tackle climate change.

There is growing evidence we’re getting close to or have already gone beyond tipping points associated with important parts of the Earth system, including warm-water coral reefs, the Amazon rainforest and the West Antarctic and Greenland ice sheets.

Warming waters are threatening West Antarctic and Greenland ice sheets.
Flickr

OK, so what do we do about it?

In our 2019 paper, we urged six critical and interrelated steps governments — and the rest of humanity — can take to lessen the worst effects of climate change:

  1. prioritise energy efficiency, and replace fossil fuels with low-carbon renewable energy
  2. reduce emissions of short-lived pollutants such as methane and soot
  3. curb land clearing to protect and restore the Earth’s ecosystems
  4. reduce our meat consumption
  5. move away from unsustainable ideas of ever-increasing economic and resource consumption
  6. stabilise and, ideally, gradually reduce human populations while improving human well-being especially by educating girls and women globally.

These solutions still apply. But in our updated 2021 paper, we go further, highlighting the potential for a three-pronged approach for near-term policy:

  1. a globally implemented carbon price
  2. a phase-out and eventual ban of fossil fuels
  3. strategic environmental reserves to safeguard and restore natural carbon sinks and biodiversity.

A global price for carbon needs to be high enough to induce decarbonisation across industry.

And our suggestion to create strategic environmental reserves, such as forests and wetlands, reflects the need to stop treating the climate emergency as a stand-alone issue.

By stopping the unsustainable exploitation of natural habitats through, for example, creeping urbanisation, and land degradation for mining, agriculture and forestry, we can reduce animal-borne disease risks, protect carbon stocks and conserve biodiversity — all at the same time.

A kangaroo in burnt bushland
There has been a worrying number of disasters since 2019, including Australia’s megafires.
Shutterstock

Is this actually possible?

Yes, and many opportunities still exist to shift pandemic-related financial support measures into climate friendly activities. Currently, only 17% of such funds had been allocated that way worldwide, as of early March 2021. This percentage could be lifted with serious coordinated, global commitment.

Greening the economy could also address the longer term need for major transformative change to reduce emissions and, more broadly, the over-exploitation of the planet.

Our planetary vital signs make it clear we need urgent action to address climate change. With new commitments getting made by governments all over the world, we hope to see the curves in our graphs changing in the right directions soon.




Read more:
11,000 scientists warn: climate change isn’t just about temperature


The Conversation


Thomas Newsome, Academic Fellow, University of Sydney; Christopher Wolf, Postdoctoral Scholar, Oregon State University, and William Ripple, Distinguished Professor and Director, Trophic Cascades Program, Oregon State University

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

US scheme used by Australian farmers reveals the dangers of trading soil carbon to tackle climate change


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Aaron Simmons, University of New England; Annette Cowie, University of New England; Brian Wilson, University of New England; Mark Farrell, CSIRO; Matthew Tom Harrison, University of Tasmania; Peter Grace, Queensland University of Technology; Richard Eckard, The University of Melbourne; Vanessa Wong, Monash University, and Warwick Badgery, The University of MelbourneSoil carbon is in the spotlight in Australia. A key plank in the Morrison government’s technology-led emissions reduction policy, it involves changing farming techniques so soils store more carbon from the atmosphere.

Farmers can encourage and accelerate this process through methods that increase plant production, such as improving nutrient management or sowing permanent pastures. For each unit of atmospheric carbon they remove in this way, farmers can earn “carbon credits” to be sold in emissions trading markets.

But not all carbon credits are created equal. In one high-profile deal in January, an Australian farm sold soil carbon credits to Microsoft under a scheme based in the United States. We analysed the methodology behind the trade, and found some increases in soil carbon claimed under the scheme were far too optimistic.

It’s just one of several problems raised by the sale of carbon credits offshore. If not addressed, the credibility of carbon trading will be undermined. Ultimately the climate – and the planet – will be the loser.

sunset on farm with cattle and trees
The integrity of soil carbon trading must be assured.
Shutterstock

What is soil carbon trading?

Plants naturally remove carbon dioxide (CO₂) from the air through photosynthesis. As plants decompose, carbon-laden organic matter is added to the soil. If more organic matter is added than is lost, soil carbon levels increase.

Carbon trading schemes require the increase in soil carbon levels to be measured. The measurement methods are well-established, but can be costly and complex because they involve collecting and analysing large numbers of soil samples. And different carbon credit schemes measure the change in different ways – some more robust than others.

The Australian government’s Emissions Reduction Fund has a rigorous approach to soil sampling, laboratory analysis and calculation of credits. This ensures only genuine removals of atmospheric carbon are rewarded, in the form of “Australian Carbon Credit Units”.

Farmers can choose other schemes under which to earn carbon credits, such as the US-based carbon offset platform Regen Network.

Regen Network’s method for estimating soil carbon largely involves collecting data via satellite imagery. The extent of physical on-the-ground soil sampling is limited.

Regen Network issues “CarbonPlus credits” to farmers deemed to have increased soil carbon stores. Farmers then sell these credits on the Regen Network trading platform.

Regen Network video explaining its remote sensing methods.

‘A number of concerns’

It was Regen Network which sold Microsoft the soil carbon credits generated by an Australian farm, Wilmot Station. Wilmot is owned by the Macdoch Group, and other Macdoch properties have also claimed carbon credits under the Regen Scheme.

Regen Network should be applauded for making its methods and calculations available online. And we appreciate Regen’s open, collaborative approach to developing its methods.

However, we have reviewed their documents and have a number of concerns:

  • the dry weight of soil in a known volume, also known as “bulk density”, is a key factor in calculating soil carbon stocks. Rather than bulk density being measured from field samples, it was calculated using an equation. We examined this method and determined it was far less reliable than field sampling
  • Estimates of soil carbon were not adjusted for gravel content. Because gravel contains no carbon, carbon stock may have been overestimated
  • The remote sensing used by Regen Network involved assessment of vegetation cover via satellite imagery, from which soil carbon levels were estimated. However, vegetation cover obscures soil, and research has found predictions of soil carbon using this method are highly uncertain.



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Wilmot increased soil carbon, or “sequestration”, through changes to grazing and pasture management. The resulting rates of carbon storage calculated by Regen Network were extremely high – 7,660 tonnes of carbon over 1,094 hectares. This amounts to 7 tonnes of carbon per hectare from 2018 to 2019.

These results are not consistent with our experience of what is possible through pasture management. For example, the CSIRO has documented soil carbon increases of 0.1 to 0.3 tonnes of carbon per hectare per year in Australia from a range of methods to increase pasture production.

We believe inaccurate methods have led to the carbon increase being overestimated. Thus, it appears excess carbon credits may have been awarded.

Many carbon trading schemes apply rules to ensure integrity is maintained. These include:

  • an “additionality test” to ensure the extra carbon storage in the soil would not have happened anyway. It would prevent, for example, farmers claiming credits for practices they adopted in the past
  • ensuring sequestered carbon is maintained over time
  • disallowing double-counting of credits – for example, by preventing a country claiming credits that have been sold offshore.

The Emissions Reduction Fund and other well-recognised international schemes, such as Verra and Gold Standard, apply these rules stringently. Regen Network’s safeguards are less rigorous.

Responses to these claims from Regen Network and Macdoch Group can be found at the end of this article. A full response from Regen can also be found here.

diagram. showing arms, money, laptop and leaves over world map
Carbon trading is a way for farmers to make money by changing their land management practices.
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Not in the national interest?

Putting aside the problems noted above, the offshore sale of soil carbon credits generated by Australian farmers raises other concerns.

First, selling credits offshore means Australia loses out, by not being able to claim the abatement towards our own government and industry targets.

Second, soil carbon does not have unlimited emissions reduction potential. The quantum of carbon that can be stored in each hectare of soil is constrained, and limited by factors such as land availability and climate change. So measures to increase soil carbon should not detract from society’s efforts to reduce emissions from fossil fuel use.

And third, ensuring carbon remains in soil long after it’s deposited is a challenge because soil microbes break down organic matter. Carbon credit schemes commonly manage this by requiring a “buffer” of unsold credits. If stored carbon is lost, farmers must relinquish credits from the buffer.

If the loss is greater than the buffer, credits must be purchased to make up the difference. This exposes farmers to financial risk, especially if carbon prices rise.




Read more:
We need more carbon in our soil to help Australian farmers through the drought


farmer sits on rock
Poorly managed carbon trading schemes can put farmers at financial risk.
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Getting it right

Soil carbon is a promising way for Australia to substantially reduce its emissions. But methods used to measure gains in soil carbon must be accurate.

Carbon markets must be regulated to ensure credit is awarded for genuine abatement, and risks to farmers are limited. And the extent to which offshore carbon markets prevent Australia from meeting its own obligations to reduce emissions should be clarified and managed.

Improving the integrity of soil carbon trading will have benefits beyond emissions reduction. It will also improve soil health and farm productivity, helping agriculture become more resilient under climate change.


Regen Network response

Regen Network provided The Conversation with a response to concerns raised in this article. The full nine-page statement provided by Regen Network is available here.

The following is a brief summary of Regen Network’s statement:

– Limited on-ground soil sampling: Regen Network said its usual minimum number of soil samples was not reached in the case of Wilmot Station, because historical soil samples – taken before the project began – were used. To compensate for this, relevant sample data from a different farm was combined with data from Wilmot.

“We understand the use of ancillary data does not follow best practice and our team is working hard to ensure future projects are run using a sufficient number of samples,” Regen Network said.

– Bulk density: Regen Network said the historical sample data from Wilmot did not include “bulk density” measurements needed to estimate carbon stocks, which required “deviations” from its usual methodology. However the company was taking steps to ensure such estimates in future projects “can be provided with higher degrees of accuracy”.

– Gravel content: Regen Network said lab reports for soil samples included only the weight, not volume, of gravel present. “Best sampling practice should include the gravel volume as an essential parameter for accurate bulk density measurements. We will make sure to address this in our next round of upgrades and appreciate the observation!” the statement said.

– Remote sensing of vegetation: Regen Network said it did not use vegetation assessment at Wilmot station. It tested a vegetation assessment index at another property and found it ineffective at estimating soil carbon. At Wilmot station Regen used so-called individual “spectral bands” to estimate soil carbon at locations where on-ground sampling was not undertaken.

– Sequestration rates at Wilmot: Regen Network said while it was difficult to directly compare local sequestration rates across climatic and geologic zones, the sequestration rates for the projects in question “fall within the relatively wide range of sequestration rates” reported in key scientific studies.

Regen Network said its methodology “provides a conservative estimate on the final number of credits issued”. Its statement outlines the steps taken to ensure soil carbon levels are not overestimated.

– Integrity safeguards: Regen Network said it employs standards “based both on existing standards of reputable programs […] and inputs from project developers, in order to come up with a standard that not only is rigorous but also practical”. Regen Network takes steps to ensure additionality and permanence of carbon stores, as well as avoid double counting of carbon credits generated through their platform.

A more detailed response from Regen Network can be found here.


Wilmot Station response

Wilmot Station provided the following response from Alasdair Macleod, chairman of Macdoch Group. It has been edited for brevity:

We entered into the deals with Regen Network/Microsoft because we wanted to give a hint of the huge potential that we believe exists for farmers in Australia and globally to sequester soil carbon which can be sold through offset markets or via other methods of value creation.

Whilst we recognise that the soil carbon credits generated on the Macdoch Group properties in the Regen Network/Microsoft deal will not be included in Australia’s national carbon accounts, it is our hope that over time the regulated market will move towards including appropriately rigorous transactions such as these in some form.

At the same time we have also been working closely with the Australian government, industry organisations, academia and other interested parties on Macdoch Group properties to develop appropriate soil carbon methodologies under the government’s Climate Solutions Fund.

This is because carbon measurement methodologies are an evolving science. We have always acknowledged and will welcome improvements that will be made over the coming years to the methodologies utilised by both the voluntary and regulated markets.

In any event it has become clear that there is huge demand from the private sector for offset deals of this nature and we will continue to work towards ensuring that other farmers can take advantage of the opportunities that will become available to those that are farming in a carbon-friendly fashion.The Conversation

Aaron Simmons, Adjunct Senior Research Fellow, University of New England; Annette Cowie, Adjunct Professor, University of New England; Brian Wilson, Associate Professor, University of New England; Mark Farrell, Principal Research Scientist, CSIRO; Matthew Tom Harrison, Associate Professor of Sustainable Agriculture, University of Tasmania; Peter Grace, Professor of Global Change, Queensland University of Technology; Richard Eckard, Professor & Director, Primary Industries Climate Challenges Centre, The University of Melbourne; Vanessa Wong, Associate Professor, Monash University, and Warwick Badgery, Research Leader Pastures an Rangelands, The University of Melbourne

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

New research: nitrous oxide emissions 300 times more powerful than CO₂ are jeopardising Earth’s future



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Pep Canadell, CSIRO; Eric Davidson, University of Maryland, Baltimore; Glen Peters, Center for International Climate and Environment Research – Oslo; Hanqin Tian, Auburn University; Michael Prather, University of California, Irvine; Paul Krummel, CSIRO; Rob Jackson, Stanford University; Rona Thompson, Norwegian Institute for Air Research, and Wilfried Winiwarter, International Institute for Applied Systems Analysis (IIASA)

Nitrous oxide from agriculture and other sources is accumulating in the atmosphere so quickly it puts Earth on track for a dangerous 3℃ warming this century, our new research has found.

Each year, more than 100 million tonnes of nitrogen are spread on crops in the form of synthetic fertiliser. The same amount again is put onto pastures and crops in manure from livestock.

This colossal amount of nitrogen makes crops and pastures grow more abundantly. But it also releases nitrous oxide (N₂O), a greenhouse gas.

Agriculture is the main cause of the increasing concentrations, and is likely to remain so this century. N₂O emissions from agriculture and industry can be reduced, and we must take urgent action if we hope to stabilise Earth’s climate.

2000 years of atmospheric nitrous oxide concentrations. Observations taken from ice cores and atmosphere. Source: BoM/CSIRO/AAD.

Where does nitrous oxide come from?

We found that N₂O emissions from natural sources, such as soils and oceans, have not changed much in recent decades. But emissions from human sources have increased rapidly.

Atmospheric concentrations of N₂O reached 331 parts per billion in 2018, 22% above levels around the year 1750, before the industrial era began.

Agriculture caused almost 70% of global N₂O emissions in the decade to 2016. The emissions are created through microbial processes in soils. The use of nitrogen in synthetic fertilisers and manure is a key driver of this process.

Other human sources of N₂O include the chemical industry, waste water and the burning of fossil fuels.




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N₂O is destroyed in the upper atmosphere, primarily by solar radiation. But humans are emitting N₂O faster than it’s being destroyed, so it’s accumulating in the atmosphere.

N₂O both depletes the ozone layer and contributes to global warming.

As a greenhouse gas, N₂O has 300 times the warming potential of carbon dioxide (CO₂) and stays in the atmosphere for an average 116 years. It’s the third most important greenhouse gas after CO₂ (which lasts up to thousands of years in the atmosphere) and methane.

N₂O depletes the ozone layer when it interacts with ozone gas in the stratosphere. Other ozone-depleting substances, such as chemicals containing chlorine and bromine, have been banned under the United Nations Montreal Protocol. N₂O is not banned under the protocol, although the Paris Agreement seeks to reduce its concentrations.

A farmer emptying fertiliser into machinery
Reducing fertiliser use on farms is critical to reducing N₂O emissions.
Shutterstock

What we found

The Intergovernmental Panel on Climate Change has developed scenarios for the future, outlining the different pathways the world could take on emission reduction by 2100. Our research found N₂O concentrations have begun to exceed the levels predicted across all scenarios.

The current concentrations are in line with a global average temperature increase of well above 3℃ this century.

We found that global human-caused N₂O emissions have grown by 30% over the past three decades. Emissions from agriculture mostly came from synthetic nitrogen fertiliser used in East Asia, Europe, South Asia and North America. Emissions from Africa and South America are dominated by emissions from livestock manure.

In terms of emissions growth, the highest contributions come from emerging economies – particularly Brazil, China, and India – where crop production and livestock numbers have increased rapidly in recent decades.

N₂O emissions from Australia have been stable over the past decade. Increase in emissions from agriculture and waste have been offset by a decline in emissions from industry and fossil fuels.

Regional changes in N₂O emissions from human activities, from 1980 to 2016, in million tons of nitrogen per year. Data from: Tian et al. 2020, Nature. Source: Global Carbon Project & International Nitrogen Initiative.

What to do?

N₂O must be part of efforts to reduce greenhouse gas emissions, and there is already work being done. Since the late 1990s, for example, efforts to reduce emissions from the chemicals industry have been successful, particularly in the production of nylon, in the United States, Europe and Japan.

Reducing emissions from agriculture is more difficult – food production must be maintained and there is no simple alternative to nitrogen fertilisers. But some options do exist.




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In Europe over the past two decades, N₂O emissions have fallen as agricultural productivity increased. This was largely achieved through government policies to reduce pollution in waterways and drinking water, which encouraged more efficient fertiliser use.

Other ways to reduce N₂O emissions from agriculture include:

  • better management of animal manure

  • applying fertiliser in a way that better matches the needs of growing plants

  • alternating crops to include those that produce their own nitrogen, such as legumes, to reduce the need for fertiliser

  • enhanced efficiency fertilisers that lower N₂O production.

Global nitrous oxide budget 2007-16. Adopted from Tian et al. 2020. Nature. Source: Global Carbon Project & International Nitrogen Initiative.

Getting to net-zero emissions

Stopping the overuse of nitrogen fertilisers is not just good for the climate. It can also reduce water pollution and increase farm profitability.

Even with the right agricultural policies and actions, synthetic and manure fertilisers will be needed. To bring the sector to net-zero greenhouse gas emissions, as needed to stabilise the climate, new technologies will be required.




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The Conversation


Pep Canadell, Chief research scientist, Climate Science Centre, CSIRO Oceans and Atmosphere; and Executive Director, Global Carbon Project, CSIRO; Eric Davidson, Director, Appalachian Laboratory and Professor, University of Maryland, Baltimore; Glen Peters, Research Director, Center for International Climate and Environment Research – Oslo; Hanqin Tian, Director, International Center for Climate and Global Change Research, Auburn University; Michael Prather, Distinguished Professor of Earth System Science, University of California, Irvine; Paul Krummel, Research Group Leader, CSIRO; Rob Jackson, Professor, Department of Earth System Science, and Chair of the Global Carbon Project, Stanford University; Rona Thompson, Senior scientist, Norwegian Institute for Air Research, and Wilfried Winiwarter, , International Institute for Applied Systems Analysis (IIASA)

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

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



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Richard Eckard, University of Melbourne

The National Farmer’s Federation says Australia needs a tougher policy on climate, today calling on the Morrison government to commit to an economy wide target of net-zero greenhouse gas emission by 2050.

It’s quite reasonable for the farming sector to call for stronger action on climate change. Agriculture is particularly vulnerable to a changing climate, and the sector is on its way to having the technologies to become “carbon neutral”, while maintaining profitability.

Agriculture is a big deal to Australia. Farms comprise 51% of land use in Australia and contributed 11% of all goods and services exports in 2018–19. However, the sector also contributed 14% of national greenhouse gas emissions.

A climate-ready and carbon neutral food production sector is vital to the future of Australia’s food security and economy.

A tractor plowing a field.
Agriculture comprises 51% of Australia’s land use.
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Paris Agreement is driving change

Under the 2015 Paris Agreement, 196 countries pledged to reduce their emissions, with the goal of net-zero emissions by 2050. Some 119 of these national commitments include cutting emissions from agriculture, and 61 specifically mentioned livestock emissions.

Emissions from agriculture largely comprise methane (from livestock production), nitrous oxide (from nitrogen in soils) and to a lesser extent, carbon dioxide (from machinery burning fossil fuel, and the use of lime and urea on soils).




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In Australia, emissions from the sector have fallen by 10.8% since 1990, partly as a result of drought and an increasingly variable climate affecting agricultural production (for example, wheat production).

But the National Farmers’ Federation wants the sector to grow to more than A$100 billion in farm gate output by 2030 – far higher than the current trajectory of $84 billion. This implies future growth in emissions if mitigation strategies are not deployed.

Farm machinery spreading fertiliser
Farm machinery spreading fertiliser, which is a major source of agriculture emissions.
Shutterstock

Runs on the board

Players in Australia’s agriculture sector are already showing how net-zero emissions can be achieved.

In 2017, the Australian red meat sector committed to becoming carbon neutral by 2030. A number of red-meat producers have claimed to have achieved net-zero emissions including Arcadian Organic & Natural’s Meat Company, Five Founders and Flinders + Co.

Our research has shown two livestock properties in Australia – Talaheni and Jigsaw farms – have also achieved carbon neutral production. In both cases, this was mainly achieved through regeneration of soil and tree carbon on their properties, which effectively draws down an equivalent amount of carbon dioxide from the atmosphere to balance with their farm emissions.




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Other agricultural sectors including dairy, wool and cropping are actively considering their own emission reduction targets.

Carbon neutral wine is being produced, such as by Ross Hill, and Tulloch and Tahbilk.

Most of these examples are based on offsetting farm emissions – through buying carbon credits or regenerating soil and tree carbon – rather than direct reductions in emissions such as methane and nitrous oxide.

But significant options are available, or emerging, to reduce emissions of “enteric” methane – the result of fermentation in the foregut of ruminants such as cattle, sheep and goats.

Wine grapes growing on a vine
Some Australian wineries have gone carbon neutral.
Shutterstock

For example, livestock can be fed dietary supplements high in oils and tannins that restrict the microbes that generate methane in the animal’s stomach. Oil and tannins are also a byproduct of agricultural waste products such as grape marc (the solid waste left after grapes are pressed) and have been found to reduce methane emissions by around 20%.

Other promising technologies are about to enter the market. These include 3-NOP and Asparagopsis, which actively inhibit key enzymes in methane generation. Both technologies may reduce methane by up to 80%.

There are also active research programs exploring ways to breed animals that produce less methane, and raise animals that produce negligible methane later in life.

On farms, nitrous oxide is mainly lost through a process called “denitrification”. This is where bacteria convert soil nitrates into nitrogen gases, which then escape from the soil into the atmosphere. Options to significantly reduce these losses are emerging, including efficient nitrogen fertilisers, and balancing the diets of animals.

There is also significant interest in off-grid renewable energy in the agricultural sector. This is due to the falling price of renewable technology, increased retail prices for electricity and the rising cost to farms of getting connected to the grid.

What’s more, the first hydrogen-powered tractors are now available – meaning the days of diesel and petrol consumption on farms could end.

Wind turbine on a farm
Renewable energy on farms can be cheaper and easier than grid connection.
Yegor Aleyev/TASS/Sipa

More work is needed

In this race towards addressing climate change, we must ensure the integrity of carbon neutral claims. This is where standards or protocols are required.

Australian researchers have recently developed a standard for the red meat sector’s carbon neutral target, captured in simple calculators aligned with the Australian national greenhouse gas inventory. This allow farmers to audit their progress towards carbon neutral production.

Technology has moved a long way from the days when changing the diet of livestock was the only option to reduce farm emissions. However significant research is still required to achieve a 100% carbon neutral agriculture sector – and this requires the Australian government to co-invest with agriculture industries.

And in the long term, we must ensure measures to reduce emissions from farming also meet targets for productivity, biodiversity and climate resilience.




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The Conversation


Richard Eckard, Professor & Director, Primary Industries Climate Challenges Centre, University of Melbourne

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

Emissions of methane – a greenhouse gas far more potent than carbon dioxide – are rising dangerously



Sukree Sukplang/Reuters

Pep Canadell, CSIRO; Ann Stavert; Ben Poulter, NASA; Marielle Saunois, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ) – Université Paris-Saclay ; Paul Krummel, CSIRO, and Rob Jackson, Stanford University

Fossil fuels and agriculture are driving a dangerous acceleration in methane emissions, at a rate consistent with a 3-4℃ rise in global temperatures this century.

Our two papers published today provide a troubling report card on the global methane budget, and explore what it means for achieving the Paris Agreement target of limiting warming to well below 2℃.

Methane concentration in the atmosphere reached 1,875 parts per billion at the end of 2019 – more than two and a half times higher than pre-industrial levels.

Once emitted, methane stays in the atmosphere for about nine years – a far shorter period than carbon dioxide. However its global warming potential is 86 times higher than carbon dioxide when averaged over 20 years and 28 times higher over 100 years.

In Australia, methane emissions from fossil fuels are rising due to expansion of the natural gas industry, while agriculture emissions are falling.

Agriculture and fossil fuels are driving the rise in methane emissions.
EPA

Balancing the global methane budget

We produced a methane “budget” in which we tracked both methane sources and sinks. Methane sources include human activities such as agriculture and burning fossil fuels, as well as natural sources such as wetlands. Sinks refer to the destruction of methane in the atmosphere and soils.

Our data show methane emissions grew almost 10% from the decade of 2000-2006 to the most recent year of the study, 2017.




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Atmospheric methane is increasing by around 12 parts per billion each year – a rate consistent with a scenario modelled by the Intergovernmental Panel on Climate Change under which Earth warms by 3-4℃ by 2100.

From 2008-2017, 60% of methane emissions were man-made. These include, in order of contribution:

  • agriculture and waste, particularly emissions from ruminant animals (livestock), manure, landfills, and rice farming
  • the production and use of fossil fuels, mainly from the oil and gas industry, followed by coal mining
  • biomass burning, from wood burning for heating, bushfires and burning biofuels.
2000 years of atmospheric methane concentrations. Observations taken from ice cores and atmosphere. Source: BoM/CSIRO/AAD.

The remaining emissions (40%) come from natural sources. In order of contribution, these include:

  • wetlands, mostly in tropical regions and cold parts of the planet such as Siberia and Canada
  • lakes and rivers
  • natural geological sources on land and oceans such as gas–oil seeps and mud volcanoes
  • smaller sources such as tiny termites in the savannas of Africa and Australia.

So what about the sinks? Some 90% of methane is ultimately destroyed, or oxidised, in the lower atmosphere when it reacts with hydroxyl radicals. The rest is destroyed in the higher atmosphere and in soils.

Increasing methane concentrations in the atmosphere could, in part, be due to a decreasing rate of methane destruction as well as rising emissions. However, our findings don’t suggest this is the case.

Measurements show that methane is accumulating in the atmosphere because human activity is producing it at a much faster rate than it’s being destroyed.

NASA video showing sources of global methane.

Source of the problem

The biggest contributors to the methane increase were regions at tropical latitudes, such as Brazil, South Asia and Southeast Asia, followed by those at the northern-mid latitude such as the US, Europe and China.

In Australia, agriculture is the biggest source of methane. Livestock are the predominant cause of emissions in this sector, which have declined slowly over time.

The fossil fuel industry is the next biggest contributor in Australia. Over the past six years, methane emissions from this sector have increased due to expansion of the natural gas industry, and associated “fugitive” emissions – those that escape or are released during gas production and transport.




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Tropical emissions were dominated by increases in the agriculture and waste sector, whereas northern-mid latitude emissions came mostly from burning fossil fuels. When comparing global emissions in 2000-2006 to those in 2017, both agriculture and fossil fuels use contributed equally to the emissions growth.

Since 2000, coal mining has contributed most to rising methane emissions from the fossil fuel sector. But the natural gas industry’s rapid growth means its contribution is growing.

Some scientists fear global warming will cause carbon-rich permafrost (ground in the Arctic that is frozen year-round) to thaw, releasing large amounts of methane.

But in the northern high latitudes, we found no increase in methane emissions between the last two decades. There are several possible explanations for this. Improved ground, aerial and satellite surveys are needed to ensure emissions in this vast region are not being missed.

More surveys are needed into thawing permafrost in the high northern latitudes.
Pikist

Fixing our methane leaks

Around the world, considerable research and development efforts are seeking ways to reduce methane emissions. Methods to remove methane from the atmosphere are also being explored.

Europe shows what’s possible. There, our research shows methane emissions have declined over the past two decades – largely due to agriculture and waste policies which led to better managing of livestock, manure and landfill.

Livestock produce methane as part of their digestive process. Feed additives and supplements can reduce these emissions from ruminant livestock. There is also research taking place into selective breeding for low emissions livestock.




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The extraction, processing and transport of fossil fuels contributes to substantial methane emissions. But “super-emitters” – oil and gas sites that release a large volume of methane – contribute disproportionately to the problem.

This skewed distribution presents opportunities. Technology is available that would enable super-emitters to significantly reduce emissions in a very cost effective way.

Clearly, current upward trends in methane emissions are incompatible with meeting the goals of the Paris climate agreement. But methane’s short lifetime in the atmosphere means any action taken today would bring results in just nine years. That provides a huge opportunity for rapid climate change mitigation.The Conversation

Pep Canadell, Chief research scientist, CSIRO Oceans and Atmosphere; and Executive Director, Global Carbon Project, CSIRO; Ann Stavert, Project Scientist; Ben Poulter, Research scientist, NASA; Marielle Saunois, Enseignant-chercheur, Laboratoire des sciences du climat et de l’environnement (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ) – Université Paris-Saclay ; Paul Krummel, Research Group Leader, CSIRO, and Rob Jackson, Chair, Department of Earth System Science, and Chair of the Global Carbon Project, globalcarbonproject.org, Stanford University

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

Climate explained: what if we took all farm animals off the land and planted crops and trees instead?



Kira Volkov/Shutterstock

Sebastian Leuzinger, Auckland University of Technology


CC BY-ND

Climate Explained is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change.

If you have a question you’d like an expert to answer, please send it to climate.change@stuff.co.nz


I would like to know how much difference we could make to our commitment under the Paris Agreement and our total greenhouse gas emissions if we removed all cows and sheep from the country and grew plants in their place (hemp, wheat, oats etc). Surely we could easily become carbon neutral if we removed all livestock? How much more oxygen would be produced from plants growing instead? How would this offset our emissions? And what if we returned the land the animals were on to native forests or even pine plantations?

This is an interesting question and gives me the opportunity for some nice – albeit partly unrealistic – model calculations. Before I start, just two comments regarding the question itself.

Oxygen concentrations have been relatively stable at around 21% of the air we breathe for millions of years. This will not change markedly even if carbon dioxide emissions increase for years to come. Carbon dioxide concentrations, even in the most pessimistic emissions scenarios, will only get to around 0.1% of the atmosphere, hardly affecting the air’s oxygen content.

Secondly, grazing animals like cows and sheep emit methane — and that’s what harms the climate, not the grassland itself. Hemp or wheat plantations would have a similar capacity to take up carbon dioxide as grassland. But growing trees is what makes the difference.




Read more:
Climate explained: how different crops or trees help strip carbon dioxide from the air


Here’s a back-of-the-envelope calculation to work out how New Zealand’s carbon balance would change if all livestock were removed and all agricultural land converted to forest.

If New Zealand stopped farming cows and sheep, it would remove methane emissions.
Heath Johnson/Shutterstock

Converting pasture to trees

This would remove all methane emissions from grazing animals (about 40 megatonnes of carbon dioxide equivalent per year).

New Zealand has about 10 million hectares of grassland. Let us assume that mature native bush or mature pine forests store the equivalent of roughly 1,000 tonnes of carbon dioxide per hectare.

If it takes 250 years to grow mature native forests on all former agricultural land, this would lock away 10 billion tonnes of carbon dioxide within that time span, offsetting our carbon dioxide emissions (energy, waste and other smaller sources) during the 250 years of regrowth. Because pine forest grows faster, we would overcompensate for our emissions until the forest matures (allow 50 years for this), creating a net carbon sink.

Note these calculations are based on extremely crude assumptions, such as linear growth, absence of fire and other disturbances, constant emissions (our population will increase, and so will emissions), ignorance of soil processes, and many more.

If agricultural land was used to grow crops, we would save the 40 megatonnes of carbon dioxide equivalent emitted by livestock in the form of methane, but we would not store a substantial amount of carbon per hectare.




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Steps towards a carbon-neutral New Zealand

How should we interpret this rough estimate? First, we must acknowledge even with our best intentions, we still need to eat, and converting all agricultural land to forest would leave us importing food from overseas — certainly not great for the global carbon budget.

Second, it shows if livestock numbers were at least reduced, and we all turned to a more plant-based diet, we could reduce our emissions substantially. The effect would be similar to reforesting large parts of the country.

Third, this example also shows that eventually, be it after 250 years in the case of growing native forests, or after about 50 years in the case of pine forests, our net carbon emissions would be positive again. As the forests mature, carbon stores are gradually replenished and our emissions would no longer be compensated. Mature forests eventually become carbon neutral.

Even though the above calculations are coarse, this shows that a realistic (and quick) way to a carbon-neutral New Zealand will likely involve three steps: reduction of emissions (both in the agricultural and energy sectors), reforestation (both native bush and fast growing exotics), and a move to a more plant-based diet.The Conversation

Sebastian Leuzinger, Professor, Auckland University of Technology

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