Decaying forest wood releases a whopping 10.9 billion tonnes of carbon each year. This will increase under climate change


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Marisa Stone, Griffith University; David Lindenmayer, Australian National University; Kurtis Nisbet, Griffith University, and Sebastian Seibold, Technical University of MunichIf you’ve wandered through a forest, you’ve probably dodged dead, rotting branches or stumps scattered on the ground. This is “deadwood”, and it plays several vital roles in forest ecosystems.

It provides habitat for small mammals, birds, amphibians and insects. And as deadwood decomposes it contributes to the ecosystem’s cycle of nutrients, which is important for plant growth.

But there’s another important role we have little understanding of on a global scale: the carbon deadwood releases as it decomposes, with part of it going into the soil and part into the atmosphere. Insects, such as termites and wood borers, can accelerate this process.

The world’s deadwood currently stores 73 billion tonnes of carbon. Our new research in Nature has, for the first time, calculated that 10.9 billion tonnes of this (around 15%) is released into the atmosphere and soil each year — a little more than the world’s emissions from burning fossil fuels.

But this amount can change depending on insect activity, and will likely increase under climate change. It’s vital deadwood is considered explicitly in all future climate change projections.

An extraordinary, global effort

Forests are crucial carbon sinks, where living trees capture and store carbon dioxide from the atmosphere, helping to regulate climate.
Deadwood — including fallen or still-standing trees, branches and stumps — makes up 8% of this carbon stock in the world’s forests.

Our aim was to measure the influence of climate and insects on the rate of decomposition — but it wasn’t easy. Our research paper is the result of an extraordinary effort to co-ordinate a large-scale cross-continent field experiment. More than 30 research groups worldwide took part.

White boxes on the forest floor
We used mesh cages to keep insects away from some deadwood to test their effect on decay.
Marisa Stone, Author provided

Wood from more than 140 tree species was laid out for up to three years at 55 forest sites on six continents, from the Amazon rainforest to Brisbane, Australia.
Half of these wood samples were in closed mesh cages to exclude insects from the decomposition process to test their effect, too.

Some sites had to be protected from elephants, another was lost to fire and another had to be rebuilt after a flood.

What we found

Our research showed the rate of deadwood decay and how insects contribute to it depend very strongly on climate.

We found the rate increased primarily with rising temperature, and was disproportionately greater in the tropics compared to all other cooler climatic regions.

In fact, deadwood in tropical regions lost a median mass of 28.2% every year. In cooler, temperate regions, the median mass lost was just 6.3%.

More deadwood decay occurs in the tropics because the region has greater biodiversity (more insects and fungi) to facilitate decomposition. As insects consume the wood, they render it to small particles, which speed up decay. The insects also introduce fungal species, which then finish the job.




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Wood beetles are nature’s recyclers – with a little help from fungi


Of the 10.9 billion tonnes of carbon dioxide released by deadwood each year, we estimate insect activity is responsible for 3.2 billion tonnes, or 29%.

Let’s break this down by region. In the tropics, insects were responsible for almost one-third of the carbon released from deadwood. In regions with low temperatures in forests of northern and temperate latitudes — such as in Canada and Finland — insects had little effect.

Mushrooms growing on a log
After insects break deadwood into smaller pieces, fungi are responsible for the final stages of decay.
Marisa Stone, Author provided

What does this mean in a changing climate?

Insects are sensitive to climate change and, with recent declines in insect biodiversity, the current and future roles of insects in deadwood are uncertain.

But given the vast majority of deadwood decay occurs in the tropics (93%), and that this region in general is set to become even warmer and wetter under climate change, it’s safe to say climate change will increase the amount of carbon deadwood releases each year.

Close-up of three termites in wood
Termites and other insects can speed up deadwood decay in warmer climates.
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It’s also worth bearing in mind that the amount of carbon dioxide released is still only a fraction of the total annual global deadwood carbon stock. That is, 85% of the global deadwood carbon stock remains on forest floors and continues to store carbon each year.

We recommend deadwood is left in place — in the forest. Removing deadwood may not only be destructive for biodiversity and the ability of forests to regenerate, but it could actually substantially increase atmospheric carbon.




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For example, if we used deadwood as a biofuel it could release the carbon that would otherwise have remained locked up each year. If the world’s deadwood was removed and burned, it would be release eight times more carbon than what’s currently emitted from burning fossil fuels.

This is particularly important in cooler climatic regions, where decomposition is slower and deadwood remains for several years as a vital carbon sink.

Lush, green forest
Deadwood is essential for a healthy forest ecosystem.
Milk tea/Unsplash, CC BY

What next?

The complex interplay of interactions between insects and climate on deadwood carbon release makes future climate projections a bit tricky.

To improve climate change predictions, we need much more detailed research on how communities of decomposer insects (such as the numbers of individuals and species) influence deadwood decomposition, not to mention potential effects from insect diversity loss.

But insect diversity loss is also likely to vary regionally and would require long-term studies over decades to determine.

For now, climate scientists must take the enormous annual emissions from deadwood into account in their research, so humanity can have a better understanding of climate change’s cascading effects.




Read more:
Trees can’t save us from climate change – but society will always depend on forests – podcast


The Conversation


Marisa Stone, Adjunct Research Fellow, Centre for Planetary Health and Food Security, Griffith University; David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University; Kurtis Nisbet, Scientific Officer, Griffith University, and Sebastian Seibold, Adjunct Teaching Professor, Technical University of Munich

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

As the world battles to slash carbon emissions, Australia considers paying dirty coal stations to stay open longer


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Tim Nelson, Griffith University and Joel Gilmore, Griffith UniversityA long-anticipated plan to reform Australia’s electricity system was released on Thursday. One of the most controversial proposals by the Energy Security Board (ESB) concerns subsidies which critics say will encourage dirty coal plants to stay open longer.

The subsidies, under a so-called “capacity mechanism”, would aim to ensure reliable energy supplies as old coal plants retire.

Major coal generators say the proposal will achieve this aim. But renewables operators and others oppose the plan, saying it will pay coal plants for simply existing and delay the clean energy transition.

So where does the truth lie? Unless carefully designed, the proposal may enable coal generators to keep polluting when they might otherwise have closed. This is clearly at odds with the need to rapidly cut greenhouse gas emissions and stabilise Earth’s climate.

firefighter and bushfire engulfing house
Extending the life of coal plants is at odds with climate action efforts.
Dan Himbrechts/AAP

Paying coal stations to exist

The ESB provides advice to the nation’s energy ministers and comprises the heads of Australia’s major energy governing bodies.

Advice to the ministers on the electricity market redesign, released on Thursday, includes a recommendation for a mechanism formally known as the Physical Retailer Reliability Obligation (PRRO).

It would mean electricity generators are paid not only for the actual electricity they produce, which is the case now, but also for having the capacity to scale up electricity generation when needed.

Electricity prices on the wholesale market – where electricity is bought and sold – vary depending on the time of day. Prices are typically much higher when consumer demand peaks, such as in the evenings when we turn on heaters or air-conditioners. This provides a strong financial incentive for generators to provide reliable electricity at these times.

As a result of these incentives, Australia’s electricity system has been very reliable to date.

But the ESB says as more renewables projects come online, this reliability is not assured – due to investor uncertainty around when coal plants will close and how governments will intervene in the market.




Read more:
IPCC report: how to make global emissions peak and fall – and what’s stopping us


Under the proposed change, electricity retailers – the companies everyday consumers buy energy from – must enter into contracts with individual electricity generators to make capacity available to the market.

Energy authorities would decide what proportion of a generator’s capacity could be relied upon at critical times. Retailers would then pay generators regardless of whether or not they produce electricity when needed.

Submissions to the ESB show widespread opposition to the proposed change: from clean energy investors, battery manufacturers, major energy users and consumer groups. The ESB acknowledges the proposal has few supporters.

In fact, coal generators are virtually the only groups backing the proposed change. They say it would keep the electricity system reliable, because the rapid expansion of rooftop solar has lowered wholesale prices to the point coal plants struggle to stay profitable.

The ESB says the subsidy would also go to other producers of dispatchable energy such as batteries and pumped hydro. It says such businesses require guaranteed revenue streams if they’re to invest in new infrastructure.

Man gives thumbs up in front of hydro project
Prime Minister Scott Morrison at the Snowy Hydro project. Such generators would also be eligible for the proposed subsidy.
Lukas Coch/AAP

A questionable plan

In our view, the arguments from coal generators and the ESB require greater scrutiny.

Firstly, the ESB’s suggestion that the existing market is not driving investment in new dispatchable generation is not supported by recent data. As the Australian Energy Market Operator recently noted, about 3.7 gigawatts of new gas, battery and hydro projects are set to enter the market in coming years. This is on top of 3.2 gigawatts of new wind and solar under construction. Together, this totals more than four times the operating capacity of AGL’s Liddell coal plant in New South Wales.

It’s also difficult to argue the system is made more reliable by paying dispatchable coal stations to stay around longer.

One in four Australian homes have rooftop solar panels, and installation continues to grow. This reduces demand for coal-fired power when the sun is shining.

The electricity market needs generators that can turn on and off quickly in response to this variable demand. Hydro, batteries and some gas plants can do this. Coal-fired power stations cannot – they are too slow and inflexible.

Coal stations are also becoming less reliable and prone to breakdowns as they age. Paying them to stay open can block investment in more flexible and reliable resources.

Critics of the proposed change argue coal generators can’t compete in a world of expanding rooftop solar, and when large corporate buyers are increasingly demanding zero-emissions electricity.

There is merit in these arguments. The recommended change may simply create a new revenue stream for coal plants enabling them to stay open when they might otherwise have exited the market.

Governments should also consider that up to A$5.5 billion in taxpayer assistance was allocated to coal-fired generators in 2012 to help them transition under the Gillard government’s (since repealed) climate policies. Asking consumers to again pay for coal stations to stay open doesn’t seem equitable.

Steam billows from coal plant
Coal plants have already received billions in subsidies.
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The ultimate test

The nation’s energy ministers have not yet decided on the reforms. As usual, the devil will be in the detail.

For any new scheme to improve electricity reliability, it should solely reward new flexible generation such as hydro, batteries, and 100% clean hydrogen or biofuel-ready gas turbines.

For example, reliability could be improved by establishing a physical “reserve market” of new, flexible generators which would operate alongside the existing market. This generation could be seamlessly introduced as existing generation fails and exits.

The ESB has recommended such a measure, and pivoting the capacity mechanism policy to reward only new generators could be beneficial.

The Grattan Institute
has also proposed a scheme to give businesses more certainty about when coal plant will close. Together, these options would address the ESB’s concerns.

This month’s troubling report by the Intergovernmental Panel on Climate Change was yet another reminder of the need to dramatically slash emissions from burning fossil fuels.

Energy regulators, politicians and the energy industry owe it to our children and future generations to embrace a zero-emissions energy system. The reform of Australia’s electricity market will ultimately be assessed against this overriding obligation.




Read more:
Climate change has already hit Australia. Unless we act now, a hotter, drier and more dangerous future awaits, IPCC warns


The Conversation


Tim Nelson, Associate Professor of Economics, Griffith University and Joel Gilmore, Associate Professor, Griffith 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.
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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.



Read more:
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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.

Net zero won’t be achieved in inner city wine bars: Morrison


Michelle Grattan, University of CanberraAs Scott Morrison gradually pivots his climate policy towards embracing a target of net zero emissions by 2050, he is seeking to distinguish the government from “inner city” types and political opponents who’ve been marching down that road for a long time.

The Prime Minister told a Business Council of Australia dinner on Monday the government was charting its own course “to ensure Australia is well placed to prosper through the great energy transition of our time, consistent with strong action on climate change”.

“The key to meeting our climate change ambitions is commercialisation of low emissions technology,” he said.

“We are going to meet our ambitions with the smartest minds, the best technology and the animal spirits of capitalism.”

Morrison was speaking ahead of this week’s two-day virtual summit on climate called by President Biden.

The Biden administration has made the issue a major policy priority, which has increased the pressure on Australia to sign up to the 2050 target before the Glasgow meeting on climate late in the year.

Morrison acknowledged that “we need to change our energy mix over the next 30 years on the road to net zero emissions”.

But he said “we will not achieve net zero in the cafes, dinner parties and wine bars of our inner cities.

“It will not be achieved by taxing our industries that provide livelihoods for millions of Australians off the planet, as our political opponents sought to do, when they were given the chance.

“It will be achieved by the pioneering entrepreneurialism and innovation of Australia’s industrial workhorses, farmers and scientists.

“It will be won in places like the Pilbara, the Hunter, Gladstone, Portland, Whyalla, Bell Bay, and the Riverina.

“In the factories of our regional towns and outer suburbs. In the labs of our best research institutes and scientists.

“It will be won in our energy sector. In our industrial sector. In our agricultural sector. In our manufacturing sector.

“This is where the road to net zero is being paved in Australia. And those industries and all who work in them, will reap the benefits of the changes they are making and pioneering.”

Morrison said Australia’s natural resources and its industries’ strength presented “a huge opportunity to capitalise on the new energy economy”.

“And let’s not forget that Australia already produces many of the products that will be in growing demand as part of a low carbon future – from copper to lithium.

“It is this practical approach of making new technologies commercial that will see us achieve our goals.”

He said Australia was making real progress.

Its total emissions were 19% lower at the end of 2020 than in 2005.

“Our domestic emissions have already fallen by 36% from 2005 levels.

“Australia has deployed renewable energy ten times faster than the global average and four times faster than in Europe and the United States.

“One in four rooftops has solar, more than anywhere else in the world.

“Australia takes our emission reductions targets very seriously. We don’t make them lightly. We prepare our plan to achieve them and we follow through.”The Conversation

Michelle Grattan, Professorial Fellow, University of Canberra

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

Climate explained: rising carbon emissions (probably) won’t make the Earth uninhabitable


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Laura Revell, University of Canterbury


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


Even with all humanity’s carbon emissions to date, there’s a lot less carbon dioxide in Earth’s atmosphere than Venus, and Earth is further away from the Sun. But if carbon emissions continue at the current rate, is there any risk of reaching a tipping point at which a runaway greenhouse effect takes over, making Earth uninhabitable for any form of life?

When sunlight enters the Earth’s atmosphere, some is reflected back to space by clouds, some is reflected by bright surfaces such as ice and snow and some is absorbed by the land surface and ocean.

To maintain a balance, the Earth emits energy back to space in the form of infrared, or longwave, radiation. Some longwave radiation is absorbed in the atmosphere by heat-trapping gases, such as carbon dioxide.

This is the well-known greenhouse effect.




Read more:
Climate Explained: what Earth would be like if we hadn’t pumped greenhouse gases into the atmosphere


As is already well established, concentrations of carbon dioxide have increased over the past 250 years, causing the average surface temperature to increase.

One consequence of increasing atmospheric carbon dioxide concentrations is that, as the atmosphere warms, it can contain more water vapour. Since water vapour is itself a greenhouse gas, this can create an amplifying effect.

In general, as surface temperature increases, the Earth emits more longwave radiation to space to maintain the energy balance. But there is a limit to how much longwave radiation can be emitted.

If the atmosphere becomes completely saturated with water vapour, the Earth’s surface and lower atmosphere warm up, but further increases in emission of longwave radiation are not possible.

The runaway greenhouse

This is termed a runaway greenhouse and would mean the Earth would become lethally hot and unable to cool itself by emitting heat to space.

Ultimately, this is the fate of the Earth. In billions of years from now the Sun will become brighter and grow into a Red Dwarf. As the Sun’s luminosity increases, the Earth will become hotter and its oceans will evaporate.

We’re doomed … but not for billions of years.

The hot and steamy atmosphere will ensure the Earth is just as uninhabitable to current life-forms as Venus is today.

But could we bring such a situation about on a shorter timeframe through continued carbon dioxide emissions? The good news is, probably not.

We’re safe, for now

Previous research has found that, due to differences in the properties of water vapour and carbon dioxide as greenhouse gases, adding carbon dioxide to the atmosphere is likely insufficient to trigger a runaway greenhouse.

Atmospheric carbon dioxide is currently around 416 parts per million (ppm) – up from approximately 280 ppm since the first industrial revolution began, some 250 years ago.

In geological terms, this is a very large increase to take place over a short period of time. Yet human emissions of carbon dioxide are considered insufficient to trigger a runaway greenhouse, given the fossil fuel reserves available.

The Earth should be safe from a runaway greenhouse developing for at least another 1.5 billion years.

But then …

The caveat to all the above is that the models scientists use to study future climate are built based on past, known conditions. It is therefore difficult to predict how certain parts of the climate system might operate under extremely high greenhouse gas emissions scenarios.

Clouds hiding the Sun but with rays of light emerging from behind top.
Clouds can reflect sunlight back to space.
Flickr/scheendijk, CC BY

For example, clouds can reflect sunlight back to space, or they can trap heat emitted by the Earth. In a warming world, scientists are still unclear on the role clouds will play.




Read more:
Expect the new normal for NZ’s temperature to get warmer


While a runaway greenhouse would make Earth completely uninhabitable to life as we know it, the losses that may accrue from just a few degrees Celsius of global warming are serious and must not be discounted.

Sea level rise, increased frequency and intensity of extreme weather events, threats to endangered species and unique ecosystems are just a few of the many reasons we have to be concerned.

The silver lining is we (probably) don’t need to worry about becoming like our neighbour Venus any time soon.The Conversation

We’re not heading this way just yet.

Laura Revell, Senior Lecturer in Environmental Physics, University of Canterbury

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

The European Union wants to impose carbon tariffs on Australian exports. Is that legal?


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Felicity Deane, Queensland University of TechnologyWhat Australian politicians call carbon tariffs, the European Union labels a carbon border adjustment mechanism.

While one sounds bad (the World Trade Organisation has rules that restrict tariffs) the other sounds understandable — if the European Union is imposing a carbon tax on its own products as Australia once did, surely it is reasonable to impose it on products from overseas.

The argument is that if a German steel manufacturer has to pay a tax of, say, $77 a tonne for the carbon it emits while making the steel, an Australian manufacturer should be charged the same when its product enters the country, unless it has already paid the same tax here.

To do otherwise would give the Australian product an unfair price advantage — it would create “carbon leakage” of the kind Australian businesses used to warn about in the leadup to Australia’s carbon price.

The European Union approved the idea in principle on March 10.

The details are less than clear, in part because it is possible that carbon tariffs are not permitted under the rules of the World Trade Organisation to which European nations and most other nations belong.

WTO rules might help Australia…

The rules say taxes or “charges of any kind” can only be imposed on imported products the same way as they are domestically.

That appears to mean that they can be imposed on importers but not on producers, which isn’t quite what the European Union has in mind.

Ideally the World Trade Organisation would be able to provide guidance, but (in part because of the actions of the US Trump administration) it isn’t really in a position to do.

…if only they were enforceable

New World Trade Organisation director general Ngozi Okonjo-Iweala.
Fabrice Coffrini/AP

The WTO has a new director general in Ngozi Okonjo-Iweala who took office this month, but it will remain in an “induced coma” for as long as its appellate body is unable to hear disputes.

Under Trump, the US kept vetoing appointments to the appellate body until the expiration of terms of its existing members meant it no longer had a quorum.

Disputes can still be initiated by countries such as Australia, forcing consultations, but without final determinations.

Although the European Union says it wants to ensure that its adjustment mechanism complies with the WTO’s rules, it hasn’t ruled out the possibility of relying on provisions that allow exceptions.

Both sides could make a case

Exceptions are allowed for the protection of human, animal or plant life or health or the protection of an exhaustible natural resource.

The catch is these exceptions are not allowed to discriminate between countries and must not be disguised restrictions on trade.

It is arguable that an adjustment mechanism designed to protect the competitiveness of European industries will breach these provisions.




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No point complaining about it, Australia will face carbon levies unless it changes course


The European Union has suggested that border adjustments will be unnecessary when the rest of the world has matched it in committing to achieve net zero emissions by 2050, so long as these commitments are back up by real actions.

But that hasn’t happened yet, and despite talk by Prime Minister Scott Morrison of his “hope” that Australia can get to net zero by 2050, Australia hasn’t made a commitment, and hasn’t backed it with tax-like instrument.

With any World Trade Organisation determination uncertain and perhaps impossible, apart from complaining about carbon tariffs or border adjustments, there may be little Australia can do.The Conversation

Felicity Deane, Associate Professor, Queensland University of Technology

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

No point complaining about it, Australia will face carbon levies unless it changes course


John Quiggin, The University of Queensland

Reports that Britain’s prime minister Boris Johnson is considering calling for carbon border levies at the G7 summit to be held in London in June have produced a predictable reaction from the Australian government.

The levies would impose tariffs on carbon-intensive goods from countries such as Australia that haven’t adopted a carbon price or a 2050 net-zero emissions target.

Appearing to be shocked by the news, Energy Minister Angus Taylor declared that Australia is “dead against” carbon tariffs.

They were a “new form of protectionism designed to shield local industries from free trade”.

In fact they are already the policy of the European Union and the US, where President Joe Biden calls them a “carbon adjustment fee against countries that are failing to meet their climate and environmental obligations”. Canada, which has an economy-wide price on carbon, isn’t worried.

Saying you’re dead against something doesn’t stop it, and nor does asserting that it is anti free trade, when it is just as arguable that it is pro fair trade because it denies exporters from countries that aren’t taking action against climate change an unfair advantage.

Australia not the primary target

The mining industry itself made this point during the Gillard government’s introduction of Australia’s short-lived carbon price.

It would leave Australian exporters at a “disadvantage compared with international competitors”.

Australia isn’t the primary target in any event. The main aim of carbon tariffs would be to encourage China’s leader Xi Jinping to shift his country’s zero emissions date from 2060 to 2050, benefiting the rest of the world.




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If Xi Jinping does it, he’ll be on a level playing field with much of the world, although not with Australia, whose fate, like that of Britain’s Admiral Byng in 1757 would be used “to encourage the others”.

Complaining won’t much help. The International Monetary Fund has endorsed the idea, saying

in the absence of an agreement on carbon pricing – which would be by far preferable – applying the same carbon prices on the same products irrespective of where they are produced could help avoid shifting emissions out of the EU to countries with different standards

The World Trade Organisation, which has in the past has pushed back against environmental considerations in trade, is neutered.

World Trade Organisation powerless

In the late 1990s the WTO struck down a range of environmental restrictions imposed by the United States that required imported tuna to be labelled “dolphin safe” and required shrimp catchers to take action to protect turtles.

These decisions proved disastrous for the WTO, producing bitter hostility from the environmental movement and contributing to mass protests at the 1999 WTO meeting, which became known as the Battle of Seattle and ultimately killed the Doha round of trade negotiations.

Right now the WTO is in the organisational equivalent of an induced coma. By refusing to fill vacancies as they arose, the Trump Administration denied its appellate panel a quorum, forcing it to stop hearing cases.

President Donald Trump, neutered the World Trade Organisation.
AP

The result is that any appeal to the WTO against carbon border tariffs would be left in limbo. US President Joe Biden has agreed to the appointment of a new WTO director general, stalled by Trump, but is in no hurry to re-establish the appellate body.

Instead, he will first try to refashion the WTO into an organisation that supports his own policies, among them stronger environmental measures, carbon tariffs and “Buy American” provisions. When reformed, the appellate body will give complaints from Australia’s government short shrift.

Prime Minister Scott Morrison has shown some signs of recognising these realities, making baby steps towards announcing a 2050 zero emissions target.

But time is short. Morrison will have to either face down the denialists and do-nothingists on his own side of politics, or set himself, and Australia, up for a series of humiliations on the international stage, with real and damaging consequences.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.

Astronomers create 40% more carbon emissions than the average Australian. Here’s how they can be more environmentally friendly



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Adam Stevens, University of Western Australia and Sabine Bellstedt, University of Western Australia

Astronomers know all too well how precious and unique the environment of our planet is. Yet the size of our carbon footprint might surprise you.

Our study, released today in Nature Astronomy, estimated the field produces 25,000 tonnes of carbon dioxide-equivalent emissions per year in Australia. With fewer than 700 active researchers nationwide (including PhD students), this translates to 37 tonnes per astronomer per year.




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As a point of reference, the average Australian adult was responsible for 26 tonnes of emissions in 2019, total. That means the job of being an astronomer is 40% more carbon-intensive than the average Australian’s job and home life combined.

While we often defer to governments for climate policy, our global carbon footprint can be dramatically reduced if every industry promotes strategies to reduce their own footprint. For individual industries to make progress, they must first recognise just how much they contribute to the climate emergency.

Where do all the emissions come from?

We found 60% of astronomy’s carbon footprint comes from supercomputing. Astronomers rely on supercomputers to not only process the many terabytes of data they collect from observatories everyday, but also test their theories of how the Universe formed with simulations.

Antennas and a satellite dish in the foreground, with others in the background, in the WA desert.
Antennas of CSIRO’s ASKAP telescope at the Murchison Radio-astronomy Observatory in Western Australia.
CSIRO Science Image

Frequent flying has historically been par for the course for astronomers too, be it for conference attendance or on-site observatory visits all around the world. Prior to COVID-19, six tonnes of annual emissions from flights were attributed to the average astronomer.

An estimated five tonnes of additional emissions per astronomer are produced in powering observatories every year. Astronomical facilities tend to be remote, to escape the bright lights and radio signals from populous areas.

Some, like the Parkes radio telescope and the Anglo-Australian Telescope near Coonabarabran, are connected to the electricity grid, which is predominately powered by fossil fuels.

Others, like the Murchison Radio-astronomy Observatory in Western Australia, need to be powered by generators on site. Solar panels currently provide around 15% of the energy needs at the Murchison Radio-astronomy Observatory, but diesel is still used for the bulk of the energy demands.

Finally, the powering of office spaces accounts for three tonnes of emissions per person per year. This contribution is relatively small, but still non-negligible.

They’re doing it better in Germany

Australia has an embarrassing record of per-capita emissions. At almost four times the global average, Australia ranks in the top three OECD countries for the highest per-capita emissions. The problem at large is Australia’s archaic reliance on fossil fuels.

A study at the Max Planck Institute for Astronomy in Germany found the emissions of the average astronomer there to be less than half that in Australia.

The difference lies in the amount of renewable energy available in Germany versus Australia. The carbon emissions produced for each kilowatt-hour of electricity consumed at the German institute is less than a third pulled from the grid in Australia, on average.

The challenge astronomers in Australia face in reducing their carbon footprint is the same challenge all Australian residents face. For the country to claim any semblance of environmental sustainability, a swift and decisive transition to renewable energy is needed.

Taking emissions reduction into our own hands

A lack of coordinated action at a national level means organisations, individuals, and professions need to take emissions reduction into their own hands.

For astronomers, private arrangements for supercomputing centres, observatories, and universities to purchase dedicated wind and/or solar energy must be a top priority. Astronomers do not control the organisations that make these decisions, but we are not powerless to effect influence.




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The good news is this is already happening. A recent deal made by Swinburne University to procure 100% renewable energy means the OzSTAR supercomputer is now a “green machine”.

CSIRO expects the increasing fraction of on-site renewables at the Murchison Radio-astronomy Observatory has the potential to save 2,000 tonnes of emissions per year from diesel combustion. And most major universities in Australia have released plans to become carbon-neutral this decade.

As COVID-19 halted travel worldwide, meetings have transitioned to virtual platforms. Virtual conferences have a relatively minute carbon footprint, are cheaper, and have the potential to be more inclusive for those who lack the means to travel. Despite its challenges, COVID-19 has taught us we can dramatically reduce our flying. We must commit this lesson to memory.




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And it’s encouraging to see the global community banding together. Last year, 11,000 scientists from 153 countries signed a scientific paper, warning of a global climate emergency.

As astronomers, we have now identified the significant size of our footprint, and where it comes from. Positive change is possible; the challenge simply needs to be tackled head-on.The Conversation

Adam Stevens, Research Fellow in Astrophysics, University of Western Australia and Sabine Bellstedt, Research Associate in Astronomy, University of Western Australia

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

Dishing the dirt: Australia’s move to store carbon in soil is a problem for tackling climate change



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Robert Edwin White, University of Melbourne and Brian Davidson, University of Melbourne

To slow climate change, humanity has two main options: reduce greenhouse gas emissions directly or find ways to remove them from the atmosphere. On the latter, storing carbon in soil – or carbon farming – is often touted as a promising way to offset emissions from other sources such as energy generation, industry and transport.

The Morrison government’s Technology Investment Roadmap, now open for public comment, identifies soil carbon as a potential way to reduce emissions from agriculture and to offset other emissions.

In particular, it points to so-called “biochar” – plant material transformed into carbon-rich charcoal then applied to soil.

But the government’s plan contains misconceptions about both biochar, and the general effectiveness of soil carbon as an emissions reduction strategy.

Emissions rising from a coal plant.
Soil carbon storage is touted as a way to offset emissions from industry and elsewhere.
Shutterstock

What is biochar?

Through photosynthesis, plants turn carbon dioxide (CO₂) into organic material known as biomass. When that biomass decomposes in soil, CO₂ is produced and mostly ends up in the atmosphere.

This is a natural process. But if we can intervene by using technology to keep carbon in the soil rather than in the atmosphere, in theory that will help mitigate climate change. That’s where biochar comes in.

Making biochar involves heating waste organic materials in a reduced-oxygen environment to create a charcoal-like product – a process called “pyrolysis”. The carbon from the biomass is stored in the charcoal, which is very stable and does not decompose for decades.

Plant materials are the predominant material or “feedstock” used to make biochar, but livestock manure can also be used. The biochar is applied to the soil, purportedly to boost soil fertility and productivity. This has been tested on grassland, cropping soils and in vineyards.

A handful of biochar.
Biochar is produced by burning organic material in a low oxygen environment.
Shutterstock

But there’s a catch

So far, so good. But there are a few downsides to consider.

First, the pyrolysis process produces combustible gases and uses energy – to the extent that when all energy inputs and outputs are considered in a life cycle analysis, the net energy balance can be negative. In other words, the process can create more greenhouse gas emissions than it saves. The balance depends on many factors including the type and condition of the feedstock and the rate and temperature of pyrolysis.

Second, while biochar may improve the soil carbon status at a new site, the sites from which the carbon residues are removed, such as farmers’ fields or harvested forests, will be depleted of soil carbon and associated nutrients. Hence there may be no overall gain in soil fertility.




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Third, the government roadmap claims increasing soil carbon can reduce emissions from livestock farming while increasing productivity. Theoretically, increased soil carbon should lead to better pasture growth. But the most efficient way for farmers to take advantage of the growth, and increase productivity, is to keep more livestock per hectare.

Livestock such as cows and sheep produce methane – a much more potent greenhouse gas than carbon dioxide. Our analysis suggests the methane produced by the extra stock would exceed the offsetting effect of storing more soil carbon. This would lead to a net increase, not decrease, in greenhouse gas

Beef cattle grazing in a field
Farmers would have to increase stock numbers to benefit from pasture growth.
Dan Peled/AAP

A policy failure

The government plan refers to the potential to build on the success of the Emissions Reduction Fund. Among other measures, the fund pays landholders to increase the amount of carbon stored in soil through carbon credits issued through the Carbon Farming Initiative.

However since 2014, the Emissions Reduction Fund has not significantly reduced Australia’s greenhouse gas emissions – and agriculture’s contribution has been smaller still.




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So far, the agriculture sector has been contracted to provide about 9.5% of the overall abatement, or about 18.3 million tonnes. To date, it’s supplied only 1.54 million tonnes – 8.4% of the sector’s commitment.

The initiative has largely failed because several factors have made it uneconomic for farmers to take part. They include:

  • overly complex regulations
  • requirements for expensive soil sampling and analysis
  • the low value of carbon credits (averaging $12 per tonne of CO₂-equivalent since the scheme began).
A farmer inspecting crops.
For many farmers, taking part in the Emissions Reduction Fund is uneconomic.
Shutterstock

A misguided strategy

We believe the government is misguided in considering soil carbon as an emissions reduction technology.

Certainly, increasing soil carbon at one location can boost soil fertility and potentially productivity, but these are largely private landholder benefits – paid for by taxpayers in the form of carbon credits.




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If emissions reduction is seen as a public benefit, then the payment to farmers becomes a subsidy. But it’s highly questionable whether the public benefit (in the form of reduced emissions) is worth the cost. The government has not yet done this analysis.

To be effective, future emissions technology in Australia should focus on improving energy efficiency in industry, the residential sector and transport, where big gains are to be made.The Conversation

Robert Edwin White, Professor Emeritus, University of Melbourne and Brian Davidson, Senior Lecturer, Department of Agriculture and Food Systems, University of Melbourne

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

Gabon’s large trees store huge amounts of carbon. What must be done to protect them



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John Poulsen, Duke University

Large trees are the living, breathing giants that tower over tropical forests, providing habitat and food for countless animals, insects and other plants. Could these giants also be the key to slowing climate change?

The Earth’s climate is changing rapidly due to the buildup of greenhouse gases, like carbon dioxide, in the atmosphere as a result of human activities. Trees absorb carbon from the air and store it in their trunks, branches, and roots. In general, the larger the tree, the more carbon it stores.

Globally, tropical forests remove a staggering 15% of carbon dioxide emissions that humans produce. Africa’s tropical forests – the second largest block of rainforest in the world – have a large role to play in slowing climate change.

But large trees are in trouble everywhere. I carried out research to examine the distribution, drivers and threats to large trees in Gabon. Gabon has 87% forest cover and is the second most forested country in the world.

By carrying out this project, I was able to identify areas with a wealth of large trees (and therefore key carbon stores and sinks), what needed to be done to better protect them and eventually recommend those areas as a priority for conservation.

National inventory

In 2012, the government of Gabon began a national inventory of its forests to measure the amount of carbon stored in its trees – one of the first nationwide efforts in the tropics.

An inventory of this scale isn’t easy, especially in a heavily forested country. Technicians from Gabon’s National Parks Agency travelled to every corner of the country, sometimes hiking more than two days crossing swamps and traversing rivers, to measure the diameter and height of trees in plots a bit larger in size than a soccer field.

Using Gabon’s new inventory of 104 plots, we calculated the amount of carbon in 67,466 trees, representing at least 578 different species. We did this by applying equations to the tree measurements.

The results indicated that the density of carbon stored in Gabon’s trees is among the highest in the world. On average, Gabon’s old growth forests harbour more carbon per area than old growth forests in Amazonia and Asia.

Most of this carbon is stored in the largest trees – those with diameters bigger than 70cm at 1.3 meters from the ground. Just the largest 5% of trees stored 50% of the forest carbon. In other words, 3,373 trees out of the 67,466 measured trees contained half of the carbon.

Drivers of forest carbon stocks

Next, we examined the drivers of carbon stocks. What determines whether an area of forest holds many large trees and lots of carbon? Do environmental conditions or human activities have the largest impact on forest carbon stocks?

Environmental factors – such as soil fertility and depth, temperature, precipitation, slope and elevation – often influence the amount of carbon in a forest. During photosynthesis, trees harness energy from the sun to convert water, carbon dioxide, and minerals into carbohydrates for growth. Therefore, forests with low levels of soil minerals or that receive little rainfall should store less carbon than areas with abundant minerals and water.

Human activities – like agriculture and logging – also influence carbon stocks. Cutting down trees for timber, to clear land for farming, or for construction reduces the amount of carbon stored in forests.

We examined the amount of carbon in each tree plot in relation to the environmental factors and human activities associated with the plot. Surprisingly, we found that human activities, not environmental factors, overwhelmingly affect carbon stocks.

The impact of human activities on forest carbon was largely unexpected because of Gabon’s high forest cover (the second highest of any country) and low population density (9 people per square kilometer), 87% of which is located in urban areas. If human impacts are this strong in Gabon, what must their effects be in other tropical nations?

Although we don’t know for sure, we believe past and present swidden (slash-and-burn) agriculture is the principle cause for low carbon stocks in some areas. Forests close to villages had lower levels of carbon, probably because forest clearing for farming converts old growth forest to secondary forest.

Interestingly, forests in logging concessions held similar amounts of carbon as old growth forests. It is too early to conclude that timber harvest doesn’t reduce carbon levels by cutting large trees, but this finding gives hope that logging concessions can be managed sustainably to conserve carbon stocks.

Importantly, forests in national parks stored roughly 25% more carbon than forests outside of parks. Thus, protecting mostly undisturbed forests can effectively conserve carbon and biodiversity.

Saving Gabon’s giants

The critical role of humans in diminishing carbon stocks is both a blessing and a curse. One one hand, the future of forests are in our hands, giving us the power to choose our fate. On the other hand, we cannot ignore the responsibility to act collectively to secure these resources while considering the interests of the countries that host them.

Gabon is taking laudable actions to conserve its forests, including a protected area network of 13 parks. In addition, Gabon is reforming its logging sector and developing a nationwide land use plan. These actions are a great start, yet continued action is necessary to curb the effects of swidden agriculture and ensure that growing industrial agriculture does not reverse Gabon’s achievements.

Intact forests can pay returns. Norway recently committed to paying Gabon $150 million for stewardship of its forests. Conservation of forests requires sacrifice by the Gabonese people. Yet, this payment demonstrates that Gabon’s large trees are a national asset that can contribute to its development as well as an international resource requiring collective action to conserve.The Conversation

John Poulsen, Associate Professor of Tropical Ecology, Duke University

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