Net zero by 2050? Even if Scott Morrison gets the Nationals on board, hold the applause


Peter Christoff, The University of MelbourneResurrected Nationals leader Barnaby Joyce is back in the saddle, facing backwards. His determination to prevent the Morrison government from adopting a target of net-zero greenhouse emissions by 2050 will again delay the renovation of Australia’s climate policy.

The Nationals’ leadership spill reportedly followed growing disquiet about Morrison’s slow pivot towards a net-zero by 2050 goal. Many Nationals MPs have indicated they don’t back the target, and Joyce says he will be “guided by the party room” on the issue.

If Morrison eventually gets the 2050 target past Joyce and passed by the joint party room, there will be little cause for celebration. In fact, the achievement will be as exciting as watching a vaudeville magician wrench an old rabbit out of a moth-eaten hat.

Australia’s premiers will yawn in unison. Every state and territory in the country has already adopted this target, or better. Yet at the end of the day, net-zero by 2050 is a risky and inadequate goal, especially for wealthy nations such as Australia.

two men and a woman
Barnaby Joyce, centre, says the Nationals’ stance on a zero-emissions target will be guided by the party room.
Mick Tsikas/AAP

A target is nothing without a plan to get there

All G7 states and 11 G20 members are aiming for net-zero emissions by mid-century. These include the United Kingdom, Japan, Canada, Germany, France, the Republic of Korea, Italy, the European Union, Argentina and the United States. China, the world’s largest emitter, has committed to net-zero by 2060.

However, as international environment law expert Professor Lavanya Rajamani has argued, net-zero targets should not automatically be applauded. First, they should be checked for their credibility, accountability and fairness. On these measures, a net-zero by 2050 target for Australia is nothing to cheer.

Why? First, because a target is nothing without an effective strategy to get there – something Australia is sorely lacking.

To successfully achieve net-zero emissions by 2050, tough short- and medium-term targets are essential to staying on track. Victoria, for example, has pledged to halve carbon emissions by 2030. The UK is aiming for a 78% reduction by 2035, reflecting its confidence in existing and emerging technologies.




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The Morrison government’s 2030 target – a 26-28% reduction below 2005 emissions levels – is not credible. Experts say a 2030 target of between 50% and 74% is needed to put Australia in line with keeping warming below 2℃ and 1.5℃ respectively – the goals of the Paris Agreement.

So what about Australia’s actual emissions-reduction measures? The Morrison government’s technology-first approach falls short of what’s needed to drive quick and deep emissions cuts.

Reaching net-zero requires substantial government funding and tax relief for investors in renewable technologies. Morrison’s announcement of an additional A$540 million for new technologies is insufficient and partly misdirected.

For instance, the government is investing in carbon capture and storage. As others have argued, the technology is increasingly commercially unviable and encourages further fossil fuel use.

In the meantime, the government is failing to assist the uptake of proven technologies such as electric vehicles, despite transport being Australia’s third-worst sector for emissions.

Close up of words on car reading 'zero emissions'
The Morrison government has failed to invest in electric vehicles.
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2050 goal is risky business

Even if Australia adopted a goal of net-zero by 2050, and measures to get there comfortably, the target is risky.

In 2018, the Intergovernmental Panel on Climate Change (IPCC) released a report on the potentially catastrophic impacts of exceeding 1.5℃ global warming. In the same report it established the idea of “net zero” as a global aim, saying achieving the target by 2050 was needed to stay below that warming threshold.

The IPCC described the emissions-reduction pathways required, but failed to emphasise crucial assumptions underlying them. Most depended on “negative emissions” – drawing down carbon from the atmosphere.

Many of those presumed drawdown measures involve land use measures that potentially threaten biodiversity or food security, for instance by requiring farmland and virgin forests to be used for growing “carbon crops”. Others involve geo-engineeering technologies which are yet to be tested or proven safe at scale.

It’s a risky strategy to avoid rapid, substantial and real emissions cuts in favour of gradual mitigation pathways that rely on such future carbon drawdown. It locks us into technologies which are problematic or don’t yet exist. To limit these risks, Australia must aim for net-zero well before 2050, predominantly via actual emissions cuts.




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bleached coral
The IPCC warned of catastrophic climate impacts, such as coral bleaching.
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A matter of fairness

The matter of equity is another where policymakers have been inattentive to nuance. The undifferentiated call for net-zero by 2050 shifts the burden and costs of effort onto poorer countries. No wonder so many developed countries have been happy to adopt it!

The United Nations Framework Convention on Climate Change, the Kyoto Protocol and the Paris Agreement each require developed countries to cut emissions faster than poorer countries – and to assist poorer countries in their efforts. This recognises the fact developed nations are largely responsible for global warming, and have the wealth and technological capacities to act.

Developing nations such as India, Pakistan and Bangladesh, as well as those in Southeast Asia, Latin America, the Pacific and Africa, are mostly below global average wealth. Forcing them to meet the same net-zero timeframe as rich nations is patently unfair.

And for the international community to achieve even the 2050 goal, China – a global emissions giant – must increase its ambition to at least net-zero by 2050 (rather than its current 2060 timeframe).

smoggy city skyline
China must accelerate its climate efforts.
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Morrison’s bind

It’s clear that rich developed countries must both aim for net-zero emissions well before 2050, and provide climate finance to assist poorer countries to do the same. Anything less will almost certainly guarantee Earth overshoots an already risky target.

Australia, given its wealth and technological means, must certainly aim for net-zero well before 2050. A report in April this year suggested reaching net-zero in 2035, to make a “fair and achievable contribution to the global task” and given our vulnerability to extreme weather.

The issue of climate finance was on the agenda at this month’s G7 summit, but critics say the final commitment – meeting an overdue spending pledge of US$100 billion a year – is inadequate considering the urgency of the task.

Just months out from a crucial UN climate summit in Glasgow in November, Scott Morrison is caught in a bind. On the global stage, he’s under increasing pressure to commit to a net-zero emissions target or face carbon tariffs. At home, he’s forced to assuage a minor coalition partner now led by a man who will reportedly push for a new coal-fired power station, and for agriculture – and potentially mining – to be exempt from emissions targets.

The looming general election will test whether rural voters are prepared to endure Joyce’s climate antics or will swing to savvy independents. And it remains to be seen whether urban voters will tolerate a prime minister whose transactional politics leaves Australia increasingly exposed at home and abroad.The Conversation

Peter Christoff, Senior Research Fellow and Associate Professor, Melbourne Climate Futures initiative, The University of Melbourne

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

Peatlands worldwide are drying out, threatening to release 860 million tonnes of carbon dioxide every year


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Yuanyuan Huang, CSIRO and Yingping Wang, CSIROPeatlands, such as fens, bogs, marshes and swamps, cover just 3% of the Earth’s total land surface, yet store over one-third of the planet’s soil carbon. That’s more than the carbon stored in all other vegetation combined, including the world’s forests.

But peatlands worldwide are running short of water, and the amount of greenhouse gases this could set loose would be devastating for our efforts to curb climate change.

Specifically, our new research in Nature Climate Change found drying peatlands could release an additional 860 million tonnes of carbon dioxide into the atmosphere every year, by around 2100. To put this into perspective, Australia emitted 539 million tonnes in 2019.

To stop this from happening, we need to urgently preserve and restore healthy, water-logged conditions in peatlands. These thirsty peatlands need water.

Peatlands are like natural archives

Peatlands are found across the world: the arctic tundra, coastal marshes, tropical swamp forests, mountainous fens and blanket bogs on subantarctic islands.

They’re characterised by having water-logged soil filled with very slowly decaying plant material (the “peat”) that accumulated over tens of thousands of years, preserved by the low-oxygen environment. This partially decomposed plant debris is locked up in the soils as organic carbon.




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Peatlands can act like natural archives, letting scientists and archaeologists reconstruct past climate, vegetation, and even human lives. In fact, an estimated 20,500 archaeological sites are preserved under or within peat in the UK.

As unique habitats, peatlands are home for many native and endangered species of plants and animals that occur nowhere else, such as the white-bellied cinclodes (Cinclodes palliatus) in Peru and Australia’s giant dragonfly (Petalura gigantea), the world’s largest. They can also act as migration corridors for birds and other animals, and can purify water, regulate floods, retain sediments and so on.

Giant dragonfly on a branch
The giant dragonfly (Petalura gigantea) is listed as endangered under NSW environment law.
Christopher Brandis/iNaturalist, CC BY-NC

But over the past several decades, humans have been draining global peatlands for a range of uses. This includes planting trees and crops, harvesting peat to burn for heat, and for other land developments.

For example, some peatlands rely on groundwater, such as portions of the Greater Everglades, the largest freshwater marsh in the United States. Over-pumping groundwater for drinking or irrigation has cut off the peatlands’ source of water.

Together with the regional drier climate due to global warming, our peatlands are drying out worldwide.

What happens when peatlands dry out?

When peat isn’t covered by water, it could be exposed to enough oxygen to fuel aerobic microbes living within. The oxygen allows the microbes to grow extremely fast, enjoy the feast of carbon-rich food, and release carbon dioxide into the atmosphere.

A marsh in Les Sables d Olonne, France. Some peatlands are also a natural sources of methane, which is a more potent greenhouse gas than carbon dioxide.
Arthur Gallois, Author provided

Some peatlands are also a natural source of methane, a potent greenhouse gas with the warming potential up to 100 times stronger than carbon dioxide.

But generating methane actually requires the opposite conditions to generating carbon dioxide. Methane is more frequently released in water-saturated conditions, while carbon dioxide emissions are mostly in unsaturated conditions.




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This means if our peatlands are getting drier, we would have an increase in emissions of carbon dioxide, but a reduction in methane emissions.

So what’s the net impact on our climate?

We were part of an international team of scientists across Australia, France, Germany, Netherlands, Switzerland, the US and China. Together, we collected and analysed a large dataset from carefully designed and controlled experiments across 130 peatlands all over the world.

In these experiments, we reduced water under different climate, soil and environmental conditions and, using machine learning algorithms, disentangled the different responses of greenhouse gases.

Our results were striking. Across the peatlands we studied, we found reduced water greatly enhanced the loss of peat as carbon dioxide, with only a mild reduction of methane emissions.

A swamp forest in Peru.
Rupesh Bhomia, Author provided

The net effect — carbon dioxide vs methane — would make our climate warmer. This will seriously hamper global efforts to keep temperature rise under 1.5℃.

This suggests if sustainable developments to restore these ecosystems aren’t implemented in future, drying peatlands would add the equivalent of 860 million tonnes of carbon dioxide to the atmosphere every year by 2100. This projection is for a “high emissions scenario”, which assumes global greenhouse gas emissions aren’t cut any further.

Protecting our peatlands

It’s not too late to stop this from happening. In fact, many countries are already establishing peatland restoration projects.

For example, the Central Kalimantan Peatlands Project in Indonesia aims to rehabilitate these ecosystems by, for instance, damming drainage canals, revegetating areas with native trees, and improving local socio-economic conditions and introducing more sustainable agricultural techniques.

Likewise, the Life Peat Restore project aims to restore 5,300 hectares of peatlands back to their natural function as carbon sinks across Poland, Germany and the Baltic states, over five years.

But protecting peatlands is a global issue. To effectively take care of our peatlands and our climate, we must work together urgently and efficiently.




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People, palm oil, pulp and planet: four perspectives on Indonesia’s fire-stricken peatlands


The Conversation


Yuanyuan Huang, Research Scientist , CSIRO and Yingping Wang, Chief research scientist, CSIRO

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

Tasmania’s reached net-zero emissions and 100% renewables – but climate action doesn’t stop there


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Rupert Posner, ClimateWorks Australia and Simon Graham, ClimateWorks AustraliaGetting to net-zero greenhouse gas emissions and 100% renewable energy might seem the end game for climate action. But what if, like Tasmania, you’ve already ticked both those goals off your list?

Net-zero means emissions are still being generated, but they’re offset by the same amount elsewhere. Tasmania reached net-zero in 2015, because its vast forests and other natural landscapes absorb and store more carbon each year than the state emits.

And in November last year, Tasmania became fully powered by renewable electricity, thanks to the island state’s wind and hydro-electricity projects.

The big question for Tasmania now is: what comes next? Rather than considering the job done, it should seize opportunities including more renewable energy, net-zero industrial exports and forest preservation – and show the world what the other side of net-zero should look like.

electricity transmission lines
Hydro-electric power and wind energy mean Tasmania runs on 100% renewable energy.
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A good start

The Tasmanian experience shows emissions reduction is more straightforward in some places than others.

The state’s high rainfall and mountainous topography mean it has abundant hydro-electric resources. And the state’s windy north is well suited to wind energy projects.

What’s more, almost half the state’s 6.81 million hectares comprises forest, which acts as a giant carbon “sink” that sucks up dioxide (CO₂) from the atmosphere.

Given Tasmania’s natural assets, it makes sense for the state to go further on climate action, even if its goals have been met.




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The Tasmanian government has gone some way to recognising this, by legislating a target of 200% renewable electricity by 2040.

Under the target, Tasmania would produce twice its current electricity needs and export the surplus. It would be delivered to the mainland via the proposed A$3.5 billion Marinus Link cable to be built between Tasmania and Victoria. The 1,500 megawatt cable would bolster the existing 500 megawatt Basslink cable.

But Tasmania’s climate action should not stop there.

artist impression of marinus link
The Marinus Link would provide a second electricity connection from Tasmania to the mainland.
http://www.marinuslink.com.au

Other opportunities await

Tasmania can use its abundant renewable electricity to decarbonise existing industrial areas. It can also create new, greener industrial precincts – clusters of manufacturers powered by renewable electricity and other zero-emissions fuels such as green hydrogen.

Zero-emission hydrogen, aluminium and other goods produced in these precincts will become increasingly sought after by countries and other states with their own net-zero commitments.




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Tasmania’s vast forests could be an additional source of economic value if they were preserved and expanded, rather than logged. As well as supporting tourism, preserving forests could enable Tasmania to sell carbon credits to other jurisdictions and businesses seeking to offset their emissions, such as through the federal government’s Emissions Reduction Fund.

The ocean surrounding Tasmania also presents net-zero economic opportunities. For example, local company Sea Forest is developing a seaweed product to be added to the feed of livestock, dramatically reducing the methane they emit.

logs on a truck
Retaining, rather than logging, Tasmania’s forests presents an economic opportunity.
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Concrete targets are needed

The Tasmanian government has commissioned a review of its climate change legislation, and is also revising its climate change action plan.

These updates give Tasmania a chance to be a global model for a post-net-zero world. But without firm action, Tasmania risks sliding backwards.

While having reached net-zero, the state has not legislated or set a requirement to maintain it. The state’s current legislated emission target is a 60% reduction by 2050 on 1990 levels – which, hypothetically, means Tasmania could increase its emissions in future.




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Also, despite reaching net-zero emissions, Tasmania still emits more than 8.36 million tonnes of CO₂ each year from sources such as transport, natural gas use, industry and agriculture. Tasmania’s emissions from all sectors other than electricity and land use have increased by 4.5% since 2005.

Without a net-zero target set in law – and a plan to stay there – these emissions could overtake those drawn down by Tasmania’s forests. In fact, a background paper prepared for the Tasmanian government shows the state’s emissions may rise in the coming years and stay “positive” until 2040 or later.

The legislation update should also include a process to set emissions targets for each sector of the economy, as Victoria has done. It should also set ambitious targets for “negative” emissions – which means sequestering more CO₂ than is emitted.

Industrial plant billowing smoke
Tasmania must cut emissions from industry and other sectors.
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Action on all fronts

Under the Paris Agreement, the world is pursuing efforts to limit global warming to 1.5℃ this century. For Australia to be in line with this goal, it must reach net-zero by the mid-2030s.

Meeting this momentous task requires action on all fronts, in all jurisdictions. Bigger states and territories are aiming for substantial emissions reductions this decade. Tasmania must at least keep its emissions net-negative, and decrease them further.

Tasmania has a golden opportunity. With the right policies, the state can solidify its climate credentials and create a much-needed economic boost as the world transitions to a low-carbon future.The Conversation

Rupert Posner, Systems Lead – Sustainable Economies, ClimateWorks Australia and Simon Graham, Senior Analyst, ClimateWorks Australia

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

‘Conditional commitments’: the diplomatic strategy that could make Australia do its fair share on climate change


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Katie Steele, Australian National UniversityThe International Energy Agency’s recent, landmark report put another glaring spotlight on Australia’s failure to act on climate change. On the same night the report was released, warning against any new fossil fuel projects, the federal government announced A$600 million for a new gas-fired power plant.

This announcement is disappointing, but not surprising.

It’s just the latest embarrassing incident from the Morrison government when it comes to climate change, as it fails to set any meaningful new targets, international climate summit after climate summit.

If we take a philosophical perspective on the issue, I believe there’s a cautious and strategic way for Australia to do its fair share, one that hasn’t been widely considered: adopting “conditional committents”.

Tackling a ‘collective action’ problem

Conditional commitments are promises to raise (or lower) emissions reduction efforts, depending on what others do. For example, imagine if Australia were to publicly affirm our Asian neighbours’ climate ambitions, and seize the opportunity to make these ambitions more concrete via a conditional offer: that we would introduce a carbon tax if China or Japan were to do so first.

So far, conditional commitments have been the domain of developing countries seeking international finance. We can see this in the “nationally determined contributions” — long-term goals under the Paris Agreement — of Angola, Nigeria and other countries, which involves raising their emissions reduction targets conditional on (typically unspecified) financial support from richer nations.

But let’s look at why conditional commitments can also work in a more effective way to boost the climate change mitigation efforts of richer countries.

Climate change has the structure of a “collective-action problem”, where many nations have an interest in jointly preventing harm. Yet the independent efforts of each are arguably not cost effective, even for relatively “altruistic” nations that place higher premium on global well-being, due to making little difference to the global outcome.

This is why Australia’s contribution to climate change is unexceptional, and yet our response to the problem significant.




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If you take a “non-consequentialist” ethical stance towards collective harms, you might think the case for ambitious emissions reductions is straightforward: it’s not acceptable to contribute to a large harm, despite making a relatively small difference.

But those with “consequentialist” reasoning will maintain we must pick our battles and concentrate on where we can do the most good. That’s the charitable reading of the Morrison government’s half-hearted climate policies.

Such a strategy certainly guards against the risks of other nations free-riding off our possible climate efforts, rendering them costly and futile. In other words, we might spend big and yet make very little difference to the climate problem and hence the well-being of Australians and other global citizens.

Wind turbines over farm
Conditional commitments could extend to fossil fuel production around the world.
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But will a concerted Australian effort to mitigate climate change necessarily achieve little good? It’s extremely risky to assume so.

Either Australia will be left out in the cold should an effective coalition of cooperating nations emerge, perhaps on the back of the slew of ambitions recently announced at US President Joe Biden’s global climate summit.

Or else the future will be as bleak for Australia, as for any other nation, should all cooperative efforts fail and we’re left to face an inhospitable climate.

Joining the climate club

Joining and enhancing an international coalition for climate action (or “climate club”) is a less risky way to negotiate a collective-action problem where much is at stake.




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An important diplomatic strategy, to this end, are conditional commitments — pledges to undertake mitigation efforts in the event other nations fulfil similar obligations.

In this way, we can ensure when we buy one small “share” in a stable climate, we get many more shares for free. That is, while the direct effects of our emissions reduction on climate change would be small, the total indirect effects — the sum of all international emissions reductions in tandem with our own — would be substantial. And well and truly worth the punt.

Let’s say there was a conditional commitment that extended to fossil fuel production: Australia would tax our coal production, if China were also to do so. If the free-rider problem is what prevents Australia from doing its fair share on climate change, this should be an attractive way forward.

Australia could then play a pivotal diplomatic role in extending the circle of conditional commitments to the other major coal producers in our region, such as India and Indonesia.




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There would be no reason for countries genuinely concerned about the global climate, such as the US under the Biden administration, to defect from this “coal tax club”. But broadening membership beyond such countries would require incentives, including special trading benefits, among those in the climate club.

This could be in the form of commitments to pursue trade in new green products, such as green steel and zero-carbon hydrogen, or exemption from border taxes (as per the European Union’s strategy).

If the more reluctant members failed to follow through on their commitments, they would be expelled from the club. But provided the incentives were good enough, this would be unlikely. And even then, it woudn’t be devastating to the collective effort, if enough enthusiastic cooperators remained.

Like a stack of dominoes

Of course, conditional commitments must be credible — others must believe they’ll be followed through. And that’s not easy to establish.

But this is where international meetings and treaties can play a crucial role. The next major international summit, COP26, will be held in November this year, where world leaders will try to agree on a new plan to tackle climate change.




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With so much at stake, there’s no reason not to make grand and far-sighted conditional commitments that reflect the kind of climate we want to collectively bring about.

With careful treaty design, nations can effectively hedge their bets: either others will come to the party and make it worthwhile to invest heavily in emissions reduction, or others will not come to the party and we make a terrible situation no worse by lack of investment.

In this way, the risks of high costs and no appreciable climate benefit are reduced for those at the vanguard of climate action. And, like a stack of dominoes, the risks are reduced for everyone else, including those yet to be born.The Conversation

Katie Steele, Associate Professor in Philosophy, Australian National University

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

Government-owned firms like Snowy Hydro can do better than building $600 million gas plants


Arjuna Dibley, The University of MelbourneThe Morrison government today announced it’s building a new gas power plant in the Hunter Valley, committing up to A$600 million for the government-owned corporation Snowy Hydro to construct the project.

Critics argue the plant is inconsistent with the latest climate science. And a new report by the International Energy Agency has warned no new fossil fuel projects should be funded if we’re to avoid catastrophic climate change.

The move is also inconsistent with research showing government-owned companies can help drive clean energy innovation. Such companies are often branded as uncompetitive, stuck in the past and unable to innovate. But in fact, they’re sometimes better suited than private firms to take investment risks and test speculative technologies.

And if the investments are successful, taxpayers, the private sector and consumers share the benefits.

Wind farm
If government-owned firms led the way in clean energy technologies, society would benefit.
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Lead, not limit

Federal energy minister Angus Taylor announced the funding on Wednesday. He said the 660-megawatt open-cycle gas turbine at Kurri Kurri will “create jobs, keep energy prices low, keep the lights on and help reduce emissions”.

Experts insist the plan doesn’t stack up economically and may operate at less than 2% capacity.

But missing from the public debate is the question of how government-owned companies such as Snowy Hydro might be used to accelerate the clean energy transition.

Australian governments (of all persuasions) have not often used the companies they own to lead in clean energy innovation. Many, such as Hydro Tasmania, still rely on decades-old hydroelectric technologies. And others, such as Queensland’s Stanwell Corporation and Western Australia’s Synergy, rely heavily on older coal and gas assets.

Asking Snowy Hydro to build a gas-fired power plant is yet another example – but it needn’t be this way.




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gas plant
Snowy Hydro has been funded to build a $600 million gas plant, but it could do better.
Shutterstock

The burning question

Globally, more than 60% of electricity comes from wholly or partially state-owned companies. In Australia, despite the 20-year trend towards electricity privatisation, government-owned companies remain important power generators.

At the Commonwealth level, Snowy Hydro provides around 20% of capacity to New South Wales and Victoria. And most electricity in Queensland, Tasmania and Western Australia is generated by state government-owned businesses.

But political considerations mean government-owned electricity companies can struggle to navigate the clean energy path.

For example in April this year, the chief executive of Stanwell Corporation, Richard Van Breda, suggested the firm would mothball its coal-powered generators before the end of their technical life, because cheap renewables were driving down power prices.

Queensland’s Labor government was reportedly unhappy with the announcement, fearing voter backlash in coal regions. Breda has since stepped down and Stanwell is reportedly backtracking on its transition plans.

Such examples beg the question: can government-owned companies ever innovate on clean energy? A growing literature in economics, as well as several real-world examples, suggest that under the right conditions, the answer is yes.




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desk showing Stanwell logo
State-owned Stanwell Corporation is reportedly back-tracking on plans to mothball its coal plants early.
Stanwell Corporation

Privatised is not always best

Economists have traditionally argued state-owned companies are not good innovators. As the argument goes, the absence of competitive market forces makes them less efficient than their private sector peers.

But recent research by academics and international policy institutions such as the OECD has shown government ownership in the electricity sector can be an asset, not a curse, for achieving technological change.

The reason runs contrary to orthodox economic thinking. While competition can lead to firm efficiency, some economists argue government-owned firms can take greater risks. Without the pressure for market-rate returns to shareholders, government enterprises may be freer to invest in more speculative technologies.

My ongoing research has shown the reality is even more complex. Whether state-owned electric companies can drive clean energy innovation depends a great deal on government interests and corporate governance rules.

For example, consider the New York Power Authority (NYPA) which, like Snowy Hydro, is wholly government owned.

New York Governor Andrew Cuomo has deliberately sought to use NYPA to decarbonise the state’s electricity grid. The government has managed the company in a way that enables it to take risks on new transmission and generation technologies that investor-owned peers cannot.

For instance, NYPA is investing in advanced sensors and computing systems so it can better manage distributed energy sources such as solar and wind. The technology will also simulate major catastrophic events, including those likely to ensue from climate change.

These investments are likely to contribute to greater grid stability and greater renewables use, benefiting not just NYPA but other electricity generators and ultimately, consumers.

Such innovation is nothing new. Also in the US, the state-owned Sacramento Municipal Utility District built one of the first utility-scale solar projects in the world in 1984.

Andrew Cuomo in front of flag
NY Governor Andrew Cuomo is using a state-owned company to aid the clean energy transition.
Mary Altaffer/AP

The way forward

More could be done to ensure Australian government-owned corporations are clean energy catalysts.

Clean energy technologies can struggle to bridge the gap from invention to widespread adoption. Public investment can bring down the price of such technologies or demonstrate their efficacy.

In this regard, government-owned companies could work with private technology firms to invest in technologies in the early stages of development, and which could have significant public benefits. For instance, in 2020, the Western Australian government-owned company Synergy sought to build a 100 megawatt battery with private sector partners.

But many problems facing state-owned companies are the result of ever-changing government policy priorities. The firms should be reformed so they are owned by government, but operated at arm’s length and with other partners. This might better enable clean energy investment without the politics.




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The Conversation


Arjuna Dibley, Visiting Researcher, Climate and Energy College, The University of Melbourne

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

The budget should have been a road to Australia’s low-emissions future. Instead, it’s a flight of fancy


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John Quiggin, The University of QueenslandLooking at other nations around the world, the path to cutting greenhouse gas emissions seems clear.

First, develop wind and solar energy and battery storage to replace coal- and gas-fired electricity. Then, replace petrol and diesel cars with electric vehicles running off carbon-free sources. Finally, replace traditionally made steel, cement and other industries with low-carbon alternatives.

In this global context, the climate policies announced in Tuesday’s federal budget are a long-odds bet on a radically different approach. In place of the approaches adopted elsewhere, the Morrison government is betting heavily on alternatives that have failed previous tests, such as carbon capture and storage. And it’s blatantly ignoring internationally proven technology, such as electric vehicles.

The government could have followed the lead of our international peers and backed Australia’s clean energy sector to create jobs and stimulate the post-pandemic economy. Instead, it’s sending the nation on a fool’s errand.

Prime Minister Scott Morrison, left, and Treasurer Josh Frydenberg shake hands
Prime Minister Scott Morrison, left, and Treasurer Josh Frydenberg should have used the budget to create jobs in the clean economy.
Mick Tsikas/AAP

Carbon-capture folly

The Morrison government is taking a “technology, not taxes” approach to emissions reduction. Rather than adopt a policy such as a carbon price – broadly considered the most effective and efficient way to cut emissions – the government has instead pinned its hopes on a low-emissions technology plan.

That means increased public spending on research and development, to accelerate the commercialisation of low emissions technologies. The problems with this approach are most obvious in relation to carbon capture and storage (CCS).

The budget contains A$263.7 million to fund new carbon capture and storage projects. This technology promises to capture some – but to date, not all – carbon dioxide at the point of emission, and then inject it underground. It would allow continued fossil fuel use with fewer emissions, but the process is complex and expensive.

In fact, recent research found of 39 carbon-capture projects examined in the United States, more than 80% ended in failure.




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The 1.5℃ global warming limit is not impossible – but without political action it soon will be


The government’s CCS funding is focused on capturing CO₂ from gas projects. This is despite the disappointing experience of Australia’s only CCS project so far, Chevron’s Gorgon gas field off Western Australia.

Some 80% of emissions from the operation were meant to be captured from 2016. But the process was delayed for three years, allowing millions of tonnes of CO₂ to enter the atmosphere. As of January this year, the project was still facing technical issues.

CCS from gas will be expensive even if it can be made to work. Santos, which has proposed a CCS project at its Moomba gas plant in South Australia, suggests a cost of $A30 per tonne of CO₂ captured.

This money would need to come from the government’s Climate Solutions Fund, currently allocated about A$2 billion over four years. If Moomba’s projected emissions reduction of 20 million tonnes a year were realised, this project alone would exhaust the fund.

two men stand over equipment
Plans to capture carbon from Chevron’s Gorgon gas project have not gone to plan.
Chevron Australia

What about electric vehicles?

There is a striking contrast between the Morrison government’s enthusiasm for carbon capture, and its neglect of electric vehicles.

It ought to be obvious that if Australia is to achieve a target of net-zero emissions by 2050 – which Treasurer Josh Frydenberg this week reiterated was his government’s preference – the road transport sector must be decarbonised by then.

The average age of Australian cars is about 10 years. This implies, given fairly steady sales, an average lifespan of 20 years. This in turn implies most petrol or diesel vehicles sold after 2030 will have to be taken off the road before the end of their useful life.

In any case, such vehicles will probably be very difficult to buy within 15 years. Manufacturers including General Motors and Volvo have announced plans to stop selling petrol and diesel vehicles by 2035 or earlier.

But the Morrison government has ruled out consumer incentives to encourage electric vehicle uptake – a policy at odds with many other nations, including the US.




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The US jumps on board the electric vehicle revolution, leaving Australia in the dust


Despite the “technology, not taxes” mantra, this week’s federal budget ignored electric vehicles. This includes a A$10 billion infrastructure spend which did not include charging stations as part of highway upgrades.

Unless the government takes action soon, Australian motorists will be faced with the choice between a limited range of second-rate petrol and diesel vehicles, or electric vehicles for which key infrastructure is missing.

It’s hard to work out why the government is so resistant to doing anything to help electric vehicles. Public support appears strong. There are no domestic carmakers left to protect.

The car retail industry is generally unenthusiastic about electric vehicles. Its business model is built on combining competitive sticker prices with a high-margin service and repair business, and electric vehicles don’t fit this model.

At the moment (although not for much longer), electric vehicles are more expensive than traditional cars to buy upfront. But they are cheaper to run and service.

There are fears of job losses in car maintenance as electric vehicle uptake increases. However, car dealers have adjusted to change in the past, and can do so in future.

electric vehicle on charge
The budget ignored electric vehicles.
Shutterstock

Wishful thinking

The Morrison government is still edging towards announcing a 2050 net-zero target in time for the United Nations Climate Change Conference in Glasgow this November. But as Prime Minister Scott Morrison himself has emphasised, there’s no point having a target without a strategy to get there.

Yet at this stage, the government’ emissions reduction strategy looks more like wishful thinking than a road map.




Read more:
Australia’s states are forging ahead with ambitious emissions reductions. Imagine if they worked together


The Conversation


John Quiggin, Professor, School of Economics, The University of Queensland

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

The outlook for coral reefs remains grim unless we cut emissions fast — new research


Morgan Pratchett, ARC Centre of Excellence for Coral Reef Studies, CC BY-ND

Christopher Cornwall, Te Herenga Waka — Victoria University of Wellington and Verena Schoepf, University of AmsterdamThe twin stress factors of ocean warming and acidification increasingly threaten coral reefs worldwide, but relatively little is known about how various climate scenarios will affect coral reef growth rates.

Our research, published today, paints a grim picture. We estimate that even under the most optimistic emissions scenarios, we’ll see dramatic reductions in coral reef growth globally.
The good news is that 63% of all reefs in this emissions scenario will still be able to grow by 2100.

But if emissions continue to rise unabated, we predict 94% of coral reefs globally will be eroding by 2050. Even under an intermediate emissions scenario, we project a worst-case outcome in which coral reefs on average will no longer be able to grow vertically by 2100.

The latter scenarios would have dramatic consequences for marine biodiversity and the millions of people who depend on healthy, actively growing coral reefs for livelihoods and shoreline protection. This highlights the urgency and importance of acting now to drastically reduce carbon dioxide emissions.

Coral reefs are home to more than 830,000 species and provide coastal communities with food and income through fisheries and tourism.

The Great Barrier Reef alone contributes A$6.4 billion to the Australian economy. Critically, coral reefs also protect coastlines from storm surges and create land for many low-lying Indo-Pacific island nations.

Marine heatwaves, caused by ongoing ocean warming, have already had a severe impact on coral reef ecosystems by triggering mass bleaching events. These events are becoming more frequent and intense, and cause mass die-offs across large areas.

Bleaching at the Great Barrier Reef
Marine heatwaves trigger mass bleaching and coral die-offs.
Morgan Pratchett, ARC Centre of Excellence for Coral Reef Studies, CC BY-ND

Ocean acidification also reduces the growth of corals by limiting their ability to build their skeletons from calcium carbonate. Together, these stressors threaten the ability of coral reefs to grow and keep up with sea level rise.

Complex impacts from ocean warming and acidification

Our understanding of how ocean warming and acidification threaten reef-forming species has improved considerably over the past decade. However, understanding how coral reef growth will be altered by climate change is more complex than simply measuring rates of change from individual taxonomic groups of corals.

Our study of 183 reefs worldwide provides the first quantitative estimate of how most of the processes that control reef growth respond to climate change and affect carbonate accumulation and growth rates.

Coral reef
Coral on the Great Barrier Reef during the 2020 bleaching event.
Morgan Pratchett, ARC Centre of Excellence for Coral Reef Studies, CC BY-ND

Reefs grow by layering calcium carbonate, produced either by corals and coralline algae. The amount of calcium carbonate built by these reefs depends on many factors.

Cyclones, waves and currents can flush parts of the reef away. Acidifying ocean water means more dissolves chemically. And there is a biological carbonate exchange, known as bio-erosion. Sponges, parrotfish, sea urchins and algae can all eat it, but then return some as defecated sand.

Depending on which of these processes dominates, coral reefs either grow and accrete vertically, or they start to erode. Most of these processes vary for each reef, and almost all are affected by climate change.




Read more:
The Great Barrier Reef outlook is ‘very poor’. We have one last chance to save it


To complicate matters, the frequency and intensity of marine heatwaves will vary geographically, making it difficult to estimate to what degree coral mass bleaching events will reduce coral cover.

In our research, we applied these local and global processes to 233 locations on 183 distinct coral reefs that vary in their species compositions and physical complexity. We found significant variability in responses to ocean acidification and warming.

Geographical and species variability

We predict coral mass bleaching events will have the largest impact on carbonate production across all sites. The world’s coral reefs have already been transformed dramatically by these events over the past few decades.

Coral bleaching at the Maledives
Coral reef in the Maldives, before coral mass bleachign event.
Chris Perry, CC BY-ND



Read more:
We just spent two weeks surveying the Great Barrier Reef. What we saw was an utter tragedy


Diver and equipment at a coral reef
Experimental setup used to measure calcification coralline algae on the Great Barrier Reef.
Guillermo Diaz-Pulido, CC BY-ND

We used the documented impacts of the 2016 mass bleaching on the Great Barrier Reef, which affected a large range of reefs with different species compositions, depths and latitudes. During this event, each reef experienced varying heat stress, which manifested in different levels of coral cover loss.

This information helped us to calibrate models to predict heat-stress events globally between now and 2100 and to gauge the future magnitudes of heat stress and their impact on our study sites.

We found currently degraded reefs fared poorly in our model, even under lower emissions scenarios. Reefs whose carbonate production was more robust against the effects of climate change tended to be those with high present-day carbonate production rates, higher contributions from coralline algae (which are also vulnerbable, but comparatively more resistant to warming than corals) and low rates of bio-erosion.

Hope for coral reefs

In higher emissions scenarios, even reefs dominated by coralline algae began to suffer as ocean acidification and warming intensified. It is also important to note that such reefs will provide different, and perhaps reduced, services compared to coral-dominated reefs because they are structurally less complex.

People standing on a coal reef
Team members assess coral health during the 2016 bleaching event in the Kimberley, Western Australia.
Christopher Cornwall, CC BY-ND

We did not explore in depth whether remaining coral reef communities could gain tolerance to rising temperatures over time. This could manifest as an increase in the proportional abundance of heat-tolerant species as more heat-sensitive corals die during mass bleaching events.

Surviving corals could acclimatise or even adapt. But whether these mechanisms could provide hope for the continued growth of coral reefs in the future — and if so, to what extent — is largely unknown. Nor can we say if more heat-tolerant corals could sustain similar rates of reef growth and structural complexity.

Coral reef in Chagos
A coral reef in Chagos before a bleaching event in April 2016.
Chris Perry, CC BY-ND

The best hope to save coral reefs and their ecological, societal and economic benefits is to reduce our carbon emissions dramatically, and quickly. Even under our projected intermediate scenarios we expect mean global erosion of coral reefs.

Under the lowest emissions scenario we examined, we expect profound changes in coral reef growth rates and their ability to provide ecosystem services. In this scenario, only some reefs will be able to keep pace with rising sea levels.

We owe it to our children and grandchildren to reduce emissions now, if we have any hope of them witnessing the majestic nature of coral reef ecosystems.The Conversation

Christopher Cornwall, Rutherford Discovery Fellow, Te Herenga Waka — Victoria University of Wellington and Verena Schoepf, Assistant Professor, University of Amsterdam

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

A great start, but still not enough: why Victoria’s new climate target isn’t as ambitious as it sounds


Anita Foerster, Monash University; Alice Bleby, UNSW, and Anne Kallies, RMIT UniversityIn a great start towards net zero emissions by 2050, the Victorian Government recently released their Climate Change Strategy, committing to halving greenhouse emissions by 2030.

Victoria’s leadership, alongside commitments from other Australian states and territories, stands in stark contrast to the poor climate performance of our federal government.

But is it enough? Climate scientists are urging Australia to do more to reduce emissions and to do it quicker if we’re going to avert dangerous global warming. In fact, a recent Climate Council report claims achieving net zero emissions by 2050 is at least a decade too late.

We think the Victorian government has the legal mandate to do more. But we also recognise that ambitious climate action at the state level is hindered by a lack of commitment at the federal level.

Using law to drive emissions reductions

Victoria’s new strategy was developed under the Climate Change Act 2017, state legislation requiring the government to set interim emissions reduction targets on the way to net zero by 2050.

It spreads the job of achieving these targets across the economy, with different ministers responsible for pledging emissions reductions actions and reporting on progress over time.

Laws like this are emerging around the world to set targets and hold governments accountable for delivering on them. They’re a key tool to deliver on international commitments under the Paris Agreement to limit global warming to well below 2℃.

Although Australia has set a national target for emissions reduction under the Paris Agreement, it’s widely considered to be inadequate, and there’s currently no framework climate law at the national level. Independent Zali Steggall introduced such a bill in 2020, but the Morrison government hasn’t supported it.

Victoria’s new strategy lacks detail

Victoria’s Climate Change Strategy contains many exciting climate policy announcements, including:

  • renewable energy zones and big batteries in the regions
  • all government operations including schools and hospitals powered by 100% renewables by 2025
  • targets and subsidies for electric vehicle uptake
  • commitments to support innovation in hard-to-abate sectors such as agriculture.

It also recognises the need to phase out natural gas and accelerate Victoria’s renewable hydrogen industry.

These policies are designed to reduce emissions while supporting economic growth and job creation. Yet they are scant on detail.

There’s heavy reliance on achieving emissions reductions in the energy sector — arguably, this is the low-hanging fruit. Policies in transport and agriculture are far less developed, with no quantification of targeted emissions reductions to 2030.

Cows in a paddock
Victoria has committed to support innovation in hard-to-abate sectors such as agriculture.
Shutterstock

This makes it difficult to assess whether the sector pledges will drive enough change to achieve the government’s interim targets (ambitious or otherwise) and support a trajectory to net zero.

It has taken several years to develop the Climate Change Strategy. This makes the lack of detail and the undeveloped nature of some pledges a big concern.

There are also few safeguards in the Climate Change Act to ensure pledges add up to achieving targets, or that ministers across sectors deliver on them. Much depends on the political will of the government of the day.

Why Victoria’s targets aren’t enough

The Victorian Government proposes targets to reduce emissions by 28–33% on 2005 levels by 2025, and by 45–50% on 2005 levels by 2030.

The government claims these targets are ambitious. Compared to current federal government targets, this is true.




Read more:
Australia’s states are forging ahead with ambitious emissions reductions. Imagine if they worked together


However, the target ranges are lower than those recommended in 2019 by the Independent Expert Panel, established under the Climate Change Act to advise the government on target setting.

The panel recommended targets of 32–39% by 2025 and 45–60% by 2030 as Victoria’s “fair share” contribution to limiting warming to well below 2℃ in accordance with Paris Agreement goals. And it acknowledged these recommended ranges still wouldn’t be enough to keep warming to 1.5℃, in the context of global efforts.

Solar panels on a roof
Reducing emissions in the energy sector is low-hanging fruit.
Shutterstock

Ultimately, Victoria’s targets don’t match what scientists are now telling us about the importance of cutting emissions early to avoid the worst impacts of climate change.

A pragmatic approach or a missed opportunity?

In setting the targets, the state government has clearly taken a politically pragmatic approach.

The government claims the targets are achievable and suggests they would’ve set more ambitious targets if the federal government made a stronger commitment to climate action.

Yes, the current lack of climate ambition at the federal level in Australia is a very real constraint on progress in some areas such as energy, where a coordinated approach is crucial. But this shouldn’t outweigh aligning to best available science.

State governments have many regulatory, policy and economic levers at their disposal, with opportunities to drive significant change and innovation. And Victoria has already demonstrated strong progress in emissions reduction and renewables in the energy sector, easily meeting and exceeding previous targets.

Under the Climate Change Act, the Victorian Government will need to set new, more ambitious targets in five years.

But waiting five years goes against Victoria’s aim to lead the nation on climate action and contribute fairly to global efforts to mitigate global warming. More ambitious, science-aligned targets now would’ve been a valuable signal for industry and a sign of real climate leadership.

We need stronger laws

Without doubt, the new Climate Change Strategy is a significant step forward on an issue that’s plagued Australian politics for years. Victoria has showed framework climate laws can drive government action on climate change.




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Conservative but green independent MP Zali Steggall could break the government’s climate policy deadlock


But there are also opportunities to bolster the Climate Change Act by aligning targets to science, strengthening legal obligations to drive timely progress, and including an ongoing role for independent experts to advise on target setting and oversee progress.

Finally, it’s important to get on with the job at a federal level.

Zali Steggall’s Climate Change Bill 2020 picks up on best practice climate laws from around the world. It’s also supported by industry groups and investors.

Victoria’s experience suggests it’s surely time for Australia to take this important step.The Conversation

Anita Foerster, Senior Lecturer, Monash University; Alice Bleby, PhD Candidate, UNSW, and Anne Kallies, Senior Lecturer, RMIT University

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

We found methane-eating bacteria living in a common Australian tree. It could be a game changer for curbing greenhouse gases


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Luke Jeffrey, Southern Cross UniversityTrees are the Earth’s lungs – it’s well understood they drawdown and lock up vast amounts of carbon dioxide from the atmosphere. But emerging research is showing trees can also emit methane, and it’s currently unknown just how much.

This could be a major problem, given methane is a greenhouse gas about 45 times more potent than carbon dioxide at warming our planet.

However, in a world-first discovery published in Nature Communications, we found unique methane-eating communities of bacteria living within the bark of a common Australian tree species: paperbark (Melaleuca quinquenervia). These microbial communities were abundant, thriving, and mitigated about one third of the substantial methane emissions from paperbark that would have otherwise ended up in the atmosphere.

Because research on tree methane (“treethane”) is still in its relative infancy, there are many questions that need to be resolved. Our discovery helps fill these critical gaps, and will change the way we view the role of trees within the global methane cycle.

Wait, trees emit methane?

Yes, you read that right! Methane gas within cottonwood trees was first reported in 1907, but has been largely overlooked for almost a century.

Only in 2018 was a tree methane review published and then a research blueprint put forward, labelling this as “a new frontier of the global carbon cycle”. It has since been gaining rapid momentum, with studies now spanning the forests of Japan, UK, Germany, Panama, Finland, China, Australia, US, Canada, France and Borneo just to name a few.

Research on tree methane is still in its relative infancy.

In some cases, treethane emissions are significant. For example, the tropical Amazon basin is the world largest natural source of methane. Trees account for around 50% of its methane emissions.

Likewise, research from 2020 found low-lying subtropical Melaleuca forests in Australia emit methane at similar rates to trees in the Amazon.

Dead trees can emit methane, too. At the site of a catastrophic climate-related mangrove forest dieback in the Gulf of Carpentaria, dead mangrove trees were discovered to emit eight times more methane than living ones. This poses new questions for how climate change may induce positive feedbacks, triggering potent greenhouse gas release from dead and dying trees.

Aerial shot of river through trees in the Amazon
Trees account for around 50% of the total Amazon basin methane emissions.
Shutterstock

Treethane emissions most likely account for some of the large uncertainties within the most recent global methane budget, which tries to determine where all the methane in the atmosphere comes from. But we’re still a long way from refining an answer to this question. Currently, trees are not yet included as a distinct emissions category.

So where exactly is the treethane coming from?

Within wetland forests, scientists assumed most treethane emissions originate from the underlying soils. The methane is transported upwards via the tree roots and stems, then through to the atmosphere via their bark.

We confirmed, in other recent research, that wetland soils were indeed the source of methane emissions in lowland forest trees. But this wasn’t always the case.

Some lowland forest trees such as cottonwood can emit flammable methane directly from their stems, which is likely produced by microbes living within the moist trees themselves. Dry upland forest trees are also emerging as methane emitters too — albeit at much lower rates.

Paperbark trees surround a body of water
Paperbark forest in a wetland, where bark-dwelling methane-eating microbes were discovered.
Luke Jeffrey, Author provided

Discovering methane-eating bacteria

For our latest research, we used microbiological extraction techniques to sample the diverse microbial communities that live within trees.

We discovered the bark of paperbark trees provide a unique home for methane-oxidizing bacteria — bacteria that “consumes” methane and turns it into carbon dioxide, a far less potent greenhouse gas.

Remarkably, these bacteria made up to 25% of total microbial communities living in the bark, and were consuming around 36% of the tree’s methane. It appears these microbes make an easy living in the dark, moist and methane-rich environments.




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


This discovery will revolutionise the way in which we view methane emitting trees and the novel microbes living within them.

Only through understanding why, how, which, when and where trees emit the most methane, may we more effectively plant forests that effectively draw down carbon dioxide while avoiding unwanted methane emissions.

Author sampling microbes from paperbark tree
Microbe sampling techniques have advanced within the last few decades, allowing us to understand the diverse microbial communities living within trees.
Luke Jeffrey, Author provided

Our discovery that bark-dwelling microbes can mitigate substantial treethane emissions complicates this equation, but provides some reassurance that microbiomes have evolved within trees to consume methane as well.

Future work will undoubtedly look further afield, exploring the microbial communities of other methane-emitting forests.

A trillion trees to combat climate change

We must be clear: trees are in no way shape or form bad for our climate and provide a swath of other priceless ecosystem benefits. And the amount of methane emitted from trees is generally dwarfed by the amount of carbon dioxide they will take in over their lifetime.

However, there are currently 3.04 trillion trees on Earth. With both upland and lowland forests capable of emitting methane, mere trace amounts of methane on a global scale may amount to a substantial methane source.

As we now have a global movement aiming to reforest large swaths of the Earth with 1 trillion trees, knowledge surrounding methane emitting trees is critical.




Read more:
Half of global methane emissions come from aquatic ecosystems – much of this is human-made


The Conversation


Luke Jeffrey, Postdoctoral Research Fellow, Southern Cross University

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

Half of global methane emissions come from aquatic ecosystems – much of this is human-made


Shutterstock

Judith Rosentreter, Yale University; Alberto Borges, Université de Liège; Ben Poulter, NASA, and Bradley Eyre, Southern Cross UniversityMethane — a greenhouse gas far more potent than carbon dioxide — plays a major role in controlling the Earth’s climate. But methane concentrations in the atmosphere today are 150% higher than before the industrial revolution.

In our paper published today in Nature Geoscience, we show as much as half of global methane emissions come from aquatic ecosystems. This includes natural, human-created and human-impacted aquatic ecosystems — from flooded rice paddies and aquaculture ponds to wetlands, lakes and salt marshes.

Our findings are significant. Scientists had previously underestimated this global methane contribution due to underaccounting human-created and human-impacted aquatic ecosystems.

It’s critical we use this new information to stop rising methane concentrations derailing our attempts to stabilise the Earth’s temperature.

From underwater sediment to the atmosphere

Most of the methane emitted from aquatic ecosystems is produced by micro-organisms living in deep, oxygen-free sediments. These tiny organisms break down organic matter such as dead algae in a process called “methanogenesis”.

Flooded rice paddies
Rice farming releases more methane per year than the entire open ocean.
Shutterstock

This releases methane to the water, where some is consumed by other types of micro-organisms. Some of it also reaches the atmosphere.

Natural systems have always released methane (known as “background” methane). And freshwater ecosystems, such as lakes and wetlands, naturally release more methane than coastal and ocean environments.

Human-made or human-impacted aquatic ecosystems, on the other hand, increase the amount of organic matter available to produce methane, which causes emissions to rise.




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


Significant global contribution

Between 2000 and 2006, global methane emissions stabilised, and scientists are still unsure why. Emissions began steadily rising again in 2007.

There’s active debate in the scientific community about how much of the renewed increase is caused by emissions or by a decline of “methane sinks” (when methane is eliminated, such as from bacteria in soil, or from chemical reactions in the atmosphere).

We looked at inland, coastal and oceanic ecosystems around the world. While we cannot resolve the debate about what causes the renewed increase of atmospheric methane, we found the combined emissions of natural, impacted and human-made aquatic ecosystems are highly variable, but may contribute 41% to 53% of total methane emissions globally.




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In fact, these combined emissions are a larger source of methane than direct anthropogenic methane sources, such as cows, landfill and waste, and coal mining. This knowledge is important because it can help inform new monitoring and measurements to distinguish where and how methane emissions are produced.

Water is a big part of much of our landscape, from mountain rivers to the coastal ocean. This aerial image shows Himalaya rivers, wetlands, lakes and ponds, and the world’s largest mangrove forest (the Sundarbans) at the coast of the tropical Bay of Bengal.
George Allen, Author provided

The alarming human impact

There is an increasing pressure from humans on aquatic ecosystems. This includes increased nutrients (like fertilisers) getting dumped into rivers and lakes, and farm dam building as the climate dries in many places.

In general, we found methane emissions from impacted, polluted and human-made aquatic ecosystems are higher than from more natural sites.

For example, fertiliser runoff from agriculture creates nutrient-rich lakes and reservoirs, which releases more methane than nutrient-poor (oligotrophic) lakes and reservoirs. Similarly, rivers polluted with nutrients also have increased methane emissions.

An aquaculture farm
Coastal aquaculture farms emit up to 430 times more methane per area than coastal habitats.
Shutterstock

What’s particularly alarming is the strong methane release from rice cultivation, reservoirs and aquaculture farms.

Globally, rice cultivation releases more methane per year than all coastal wetlands, the continental shelf and open ocean together.

The fluxes in methane emissions per area of coastal aquaculture farms are 7-430 times higher than from coastal habitats such as mangrove forests, salt marshes or seagrasses. And highly disturbed mangroves and salt marsh sites have significantly higher methane fluxes than more natural sites.

So how do we reduce methane emissions?

For aquatic ecosystems, we can effectively reduce methane emissions and help mitigate climate change with the right land use and management choices.

For example, managing aquaculture farms and rice paddies so they alternate between wet and dry conditions can reduce methane emissions.




Read more:
Climate explained: methane is short-lived in the atmosphere but leaves long-term damage


Restoring salt marsh and mangrove habitats and the flow of seawater from tides is another promising strategy to further reduce methane emissions from degraded coastal wetlands.

We should also reduce the amount of nutrients coming from fertilisers washing into freshwater wetlands, lakes, reservoirs and rivers as it leads to organic matter production, such as toxic algal blooms. This will help curtail methane emissions from inland waters.

These actions will be most effective if we apply them in the aquatic ecosystems that have the greatest contribution of aquatic methane: freshwater wetlands, lakes, reservoirs, rice paddies and aquaculture farms.

This will be no small effort, and will require knowledge across many disciplines. But with the right choices we can create conditions that bring methane fluxes down while also preserving ecosystems and biodiversity.The Conversation

Judith Rosentreter, Postdoctoral Research Fellow, Yale University; Alberto Borges, Research Director FRS-FNRS, Associate Professor at ULiège, Université de Liège; Ben Poulter, Research scientist, NASA, and Bradley Eyre, Professor of Biogeochemistry, Director of the Centre for Coastal Biogeochemistry, Southern Cross University

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