Australians could have saved over $1 billion in fuel if car emissions standards were introduced 3 years ago



Legislative action regarding vehicle emissions is overdue, and needs urgent attention by the federal government.
Shutterstock

Robin Smit, The University of Queensland; Jake Whitehead, The University of Queensland, and Nic Surawski, University of Technology Sydney

When it comes to road transport, Australia is at risk of becoming a climate villain as we lag behind international best practice on fuel efficiency.

Road transport is one of the main sources of greenhouse gas emissions and represented 16% of Australia’s total carbon dioxide emissions in 2000, growing to 21% in 2016. Total CO₂ emissions from road transport increased by almost 30% in the period 2000-16.

Fuel efficiency (CO₂ emission) standards have been adopted in around 80% of the global light vehicle market to cap the growth of transport emissions. This includes the United States, the European Union, Canada, Japan, China, South Korea and India – but not Australia.




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Emissions standards on cars will save Australians billions of dollars, and help meet our climate targets


If Australia had introduced internationally harmonised emissions legislation three years ago, households could have made savings on fuel costs to the tune of A$1 billion.

This shocking figure comes from our preliminary calculations looking at the effect of requiring more efficient vehicles to be sold in Australia.

A report, published yesterday by Transport Energy/Emission Research, looked at what Australia has achieved in vehicle fuel efficiency and CO₂ standards over the past 20 years. While Australia has considered and tried to impose standards a number of times, sadly these attempts were unsuccessful.

Legislative action on vehicle CO₂ emissions is long overdue and demands urgent attention by the Australian government.

Australian consumers are increasingly buying heavier vehicles with bigger emissions.
Shuterstock

How did Australia get here?

The most efficient versions of vehicle models offered in Australia are considerably less efficient than similar vehicles in other markets.

Australia could increasingly become a dumping ground for the world’s least efficient vehicles with sub-par emissions performance, given our lack of fuel efficiency standards. This leaves us on a dangerous path towards not only higher vehicle emissions, but also higher fuel costs for passenger travel and freight.

Australia has attempted to impose CO₂ or fuel efficiency standards on light vehicles several times over the past 20 years, but without success. While the federal government was committed to addressing this issue in 2015, four years later we are still yet to hear when – or even if – mandatory fuel efficiency standards will ever be introduced.

The general expectation appears to be that average CO₂ emission rates of new cars in Australia will reduce over time as technology advances overseas. In the absence of CO₂ standards locally, it is more likely that consumers will continue to not be offered more efficient cars, and pay higher fuel costs as a consequence.

Estimating the fuel savings

Available evidence suggests Australian motorists are paying on average almost 30% more for fuel than they should because of the lack of fuel efficiency standards.

The Australian vehicle fleet uses about 32 billion litres of fuel per year.

Using an Australian fleet model described in the TER report, we can make a conservative estimate that the passenger vehicle fleet uses about half of this fuel: 16 billion litres per year. New cars entering the fleet each year would represent about 5% of this: 800 million litres per year.

So assuming that mandatory CO₂ standards improve fuel efficiency by 27%, fuel savings would be 216 million litres per year.

In the last three years, the average fuel price across Australia’s five major cities is A$1.33 per litre. This equates to a total savings of A$287 million per year, although this would be about half the first year as new cars are purchased throughout the year and travel less, and would reduce as vehicles travel less when they age.

The savings are accumulative because a car purchased in a particular year continues to save fuel over the following years.

The table below shows a rough calculation of savings over the three year period (2016-2018), for new cars sold in the same period (Model Years 2016, 2017 and 2018).

As a result, over a period of three years, A$1.3 billion in potential savings for car owners would have accumulated.

Policy has come close, but what are we waiting for?

The Australian government is not progressing any measures to introduce a fuel efficiency target. In fact, it recently labelled Labor’s proposed fuel efficiency standard as a “car tax”.

But Australia has come close to adopting mandatory vehicle CO₂ emission standards in the past.

In late 2007, the Labor government committed to cutting emissions to achieve Australia’s obligations under the Kyoto Protocol. The then prime minister, Kevin Rudd, instructed the Vehicle Efficiency Working Group to:

… develop jointly a package of vehicle fuel efficiency measures designed to move Australia towards international best practice.

Then, in 2010, the Labor government decided mandatory CO₂ emissions standards would apply to new light vehicles from 2015. But a change in government in 2013 meant these standards did not see the light of day.

The amount of fuel that could have been saved is A$287 million per year.
Shutterstock

Things looked promising again when the Coalition government released a Vehicle Emissions Discussion Paper in 2016, followed by a draft Regulation Impact Statement in the same year.

The targets for adopting this policy in 2025, considered in the draft statement, were marked as “strong” (105g of CO₂ per km), “medium” (119g/km) and “mild” (135g/km) standards.

Under all three targets, there would be significant net cost savings. But since 2016, the federal government has taken no further action.

It begs the question: what exactly are we waiting for?

The technical state of play

Transport Energy/Emission Research conducted preliminary modelling of Australian real-world CO₂ emissions.

This research suggests average CO₂ emission rates of the on-road car fleet in Australia are actually increasing over time and are, in reality, higher than what is officially reported in laboratory emissions tests.

In fact, the gap between mean real-world emissions and the official laboratory tests is expected to grow from 20% in 2010 to 65% in 2025.

This gap is particularly concerning when we look at the lack of support for low-emissions vehicles like electric cars.




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Given that fleet turnover is slow, the benefits of fuel efficiency standards would only begin to have a significant effect several years into the future.

With continuing population growth, road travel will only increase further. This will put even more pressure on the need to reduce average real-world CO₂ emission rates, given the increasing environmental and health impacts of the vehicle fleet.

Even if the need to reduce emissions doesn’t convince you, the cost benefits of emissions standards should. The sale of less efficient vehicles in Australia means higher weekly fuel costs for car owners, which could be avoided with the introduction of internationally harmonised emissions legislation.The Conversation

Robin Smit, Adjunct professor, The University of Queensland; Jake Whitehead, Research Fellow, The University of Queensland, and Nic Surawski, Lecturer in Environmental Engineering, University of Technology Sydney

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

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Eastern China pinpointed as source of rogue ozone-depleting emissions



Sunset at Australia’s Cape Grim observatory, one of the key global background monitoring sites for CFC-11.
Paul Krummel/CSIRO, Author provided

Paul Krummel, CSIRO; Bronwyn Dunse, CSIRO; Nada Derek, CSIRO; Paul Fraser, CSIRO, and Paul Steele, CSIRO

A mysterious rebound in the emissions of ozone-depleting chemicals – despite a global ban stretching back almost a decade – has been traced to eastern China.

Research published by an international team today in Nature used a global network of monitoring stations to pinpoint the source of the rogue emissions. According to these data, 40-60% of the increase in emissions seen since 2013 is due to possibly illegal industrial activity in the Chinese provinces of Shandong and Hebei.




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Chlorofluorocarbon-11 (CFC-11) is a powerful ozone-depleting chemical that plays a major role in the appearance, each spring, of the ozone “hole” over Antarctica.

In the past, CFC-11 had been used primarily as a propellant in aerosol products and as a foam plastic blowing agent. The production and consumption (use) of CFC-11 are controlled by the global Montreal Protocol. CFC-11 consumption has been banned in developed countries since 1996, and worldwide since 2010.

This has resulted in a significant decline of CFC-11 in the atmosphere. Long-term CFC-11 measurements at Cape Grim, Tasmania, show the amount in the atmosphere peaked in 1994, and fell 14% by 2018.

However, this decline has not been as rapid as expected under the global zero production and consumption mandated by the Montreal Protocol since 2010.

Background levels of CFC-11 measured at Australia’s Cape Grim Baseline Air Pollution Station, located at the north-west tip of Tasmania.
CSIRO/Bureau of Meteorology

A 2014 study was the first to deduce that global emissions of CFC-11 stopped declining in 2002. In 2015, CSIRO scientists advised the Australian government, based on measurements compiled by the Advanced Global Atmospheric Gases Experiment (AGAGE), which includes those from Cape Grim, that emissions had risen significantly since 2011. The cause of this rebound in CFC-11 emissions was a mystery.

Global CFC-11 emissions based on atmospheric measurements compared with the expected decline of this compound in the atmosphere if compliance with the Montreal Protocol was adhered to.
CSIRO/AGAGE

An initial explanation came in 2018, when researchers led by Stephen Montzka of the US National Oceanic and Atmospheric Administration analysed the CFC-11 data collected weekly at Mauna Loa, Hawaii. They deduced that the increased emissions originated largely from East Asia – likely as a result of new, illegal production.

Montzka’s team concluded that if these increased CFC-11 emissions continued, the closure of the Antarctic ozone hole could be delayed, possibly for decades. This was a remarkable piece of detective work, considering that Mauna Loa is more than 8,000km from East Asia.

Suspicions confirmed

A still more detailed explanation is published today in the journal Nature by an international research team led by Matt Rigby of the University of Bristol, UK, and Sunyoung Park of Kyungpook National University, South Korea, together with colleagues from Japan, the United States, Australia and Switzerland. The new study uses data collected every two hours by the AGAGE global monitoring network, including data from Gosan, South Korea, and from an AGAGE-affiliated station at Hateruma, Japan. Crucially, Gosan and Hateruma are just 1,000km and 2,000km, respectively, from the suspected epicentre of CFC-11 emissions in East Asia.

The Korean and Japanese data show that these new emissions of CFC-11 do indeed come from eastern China – in particular the provinces of Shandong and Hebei – and that they have increased by around 7,000 tonnes per year since 2013.

Meanwhile, the rest of the AGAGE network has detected no evidence of increasing CFC-11 emissions elsewhere around the world, including in North America, Europe, Japan, Korea or Australia.

Yet while this new study has accounted for roughly half of the recent global emissions rise, it is possible that smaller increases have also taken place in other countries, or even in other parts of China, not covered by the AGAGE network. There are large swathes of the globe for which we have very little detailed information on CFC emissions.

Map showing the region where the increased CFC-11 emissions came from, based on atmospheric measurements and modelling.
University of Bristol/CSIRO

Nevertheless, this study represents an important milestone in atmospheric scientists’ ability to tell which regions are emitting ozone-depleting substances and in what quantities. It is now vital we find out which industries are responsible for these new emissions.

If the emissions are due to the manufacture and use of products such as foams, it is possible that, so far, we have seen in the atmosphere only a fraction of the total amount of CFC-11 that was produced illegally. The remainder could be locked up in buildings and chillers, and will ultimately be released to the atmosphere over the coming decades.




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Explainer: what is the Antarctic ozone hole and how is it made?


While our new study cannot determine which industry or industries are responsible, it does provide strong evidence that substantial new emissions of CFC-11 have occurred from China. Chinese authorities have identified, and closed down, some illegal production facilities over the past several years.

This study highlights the importance of undertaking long-term measurements of trace gases like CFC-11 to verify that international treaties and protocols are working. It also identifies shortcomings in the global networks for detecting regional emissions of ozone depleting substances. This should encourage expansion of these vital measurement networks which would lead to a capability of more rapid identification of future emission transgressions.The Conversation

Paul Krummel, Research Group Leader, CSIRO; Bronwyn Dunse, Climate Science Centre, CSIRO Oceans and Atmosphere, CSIRO; Nada Derek, Centre for Australian Weather and Climate Research, CSIRO; Paul Fraser, Honorary Fellow, CSIRO, and Paul Steele, Centre for Australian Weather and Climate Research, CSIRO

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

Will the discovery of another plastic-trashed island finally spark meaningful change?


Jennifer Lavers, University of Tasmania and Annett Finger, Victoria University

Today we learnt of yet another remote and formerly pristine location on our planet that’s become “trashed” by plastic debris.

Research published today in Scientific Reports shows some 238 tonnes of plastic have washed up on Australia’s remote Cocos (Keeling) Islands.

It’s not the first time the world has been confronted with an island drowning under debris. Perhaps it’s time to take stock of where we’re at, what we’ve learnt about plastic and figure out whether we can be bothered, or care enough, to do something meaningful.




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This South Pacific island of rubbish shows why we need to quit our plastic habit


Taking stock

In 2017, the world was introduced to Henderson Island, an exceptionally remote uninhabited island in the South Pacific. It has the dubious honour of being home to the beach with the highest ever recorded density of plastic debris (more than 4,400 pieces per metre squared).

What’s more, a single photo taken in 1992 showed Henderson Island had gone from pristine to trashed in only 23-years.

Now, the Cocos (Keeling) Islands off the coast of Australia are set to challenge that record, despite being sparsely populated and recognised for having one of Australia’s most beautiful beaches.

A recent, comprehensive survey of the Cocos (Keeling) Islands revealed mountains of plastic trash washed up on the beaches.




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While the density of debris on Cocos (a maximum of 2,506 items per square metre) was found to be less than that on Henderson Island, the total amount of debris Cocos must contend with is staggering: an estimated 414 million debris items weighing 238 tonnes.

A quarter of the identifiable items were found to be “single-use”, or disposable plastics, including straws, bags, bottles, and an estimated 373,000 toothbrushes.

At only 14 kilometres squared, the entire Cocos (Keeling) Island group is a little more than twice the size of the Melbourne CBD. So it’s hard to envision 414 million debris items in such a small area.

Lessons learned

Islands “filter” debris from the ocean. Items flow past and accumulate on beaches, providing valuable information about the quantity of plastic in the oceans.

So, what have these two studies of remote islands taught us?

South Island. A quarter of the identifiable items were found to be disposable plastics.
Cara Ratajczak, Author provided

On Cocos, the overwhelming quantity of debris you can see on the surface accounts for just 7% of the total debris present on the islands. The remaining 93% (approximately 383 million items) is buried below the sediment. Much like the proverbial iceberg, we’re only seeing the very tip of the problem.

Henderson Island, on the other hand, highlighted the terrifying pace of change, from pristine, tropical oasis to being inundated with 38 million plastic items in just two decades.

In the past 12 months alone, scientists have made other, ground-breaking discoveries that have emphasised how little we understand about the behaviour of plastic in the environment and the myriad consequences for species and habitats – including ourselves.




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Eight million tonnes of plastic are going into the ocean each year


Here are a few of the shocking discoveries:

  • microplastics were reported in bottled water, salt and beer

  • chemicals from degrading plastic in the ocean were found to disrupt photosynthesis in marine bacteria that are important to the carbon cycle, including producing the oxygen for approximately every tenth breath we take

  • degrading plastic exposed to UV sunlight (such as those on beaches) was reported to produce greenhouse gas emissions, including methane. This is predicted to increase significantly over the next 20 years in line with plastic production trends

  • microplastic particles are ingested by krill at the base of the marine food web, then fragmented into nano-sized particles

  • plastic items recovered from the ocean were found to be reservoirs and potential vectors for microbial communities with antibiotic resistant genes

  • tiny nanoplastics are transported via wind in the atmosphere and deposited in cities and even remote areas, including mountain tops

Meaningful action

Clean-ups on near-shore islands and coastal areas around cities are fantastic.

The educational component is invaluable and they provide an important sense of community. They also prevent large items, like bottles, from breaking up into hundreds or thousands of bite-sized microplastics.

But large-scale clean-ups of the Cocos (Keeling) Islands, and most other remote islands, are challenging for a variety of reasons. Getting to these locations is expensive, as would be shipping the plastic off for recycling or disposal.

There are also serious biosecurity issues relating to moving plastic debris off islands. Even if we did somehow manage to clean these remote islands, it would not be long before the beaches are trashed again, as it was estimated on Henderson Island that more than 3,500 new pieces of plastic wash up every single day.

As Heidi Taylor from Tangaroa Blue, an Australian initiative tackling marine debris, puts so aptly:

if all we ever do is clean up, that is all we will ever do.

For our clean-up efforts to be effective, they must be paired with individual behaviour change, underpinned by legislation that mandates producers to take responsibility for the entire lifecycle of their products.

Single-use items, such as razors, cutlery, scoops for coffee or laundry powder and toothbrushes were very common on the beaches of Cocos. Clearly this is an area where extended product stewardship laws (following the principles of a circular economy), coupled with informed consumer choices can lead to better decisions about the types of products we use and how and when we dispose of them.




Read more:
There’s no ‘garbage patch’ in the Southern Indian Ocean, so where does all the rubbish go?


The global plastic crisis requires immediate and wide-ranging actions that drastically reduce our plastic consumption. And large corporations and government need to adopt a leadership role.

In the EU, for instance, governments voted in March 2019 to implement a ban on the ten most prolific single-use plastic items by 2021. The rest of the world urgently needs to follow suit. Let’s stop arguing about how to clean up the mess, and start implementing meaningful preventative actions.The Conversation

Jennifer Lavers, Research Scientist, University of Tasmania and Annett Finger, Adjunct Research Fellow, Victoria University

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

There’s no ‘garbage patch’ in the Southern Indian Ocean, so where does all the rubbish go?


File 20190401 177175 1wvztzj.jpg?ixlib=rb 1.1
Plastic waste on a remote beach in Sri Lanka.
Author provided

Mirjam van der Mheen, University of Western Australia; Charitha Pattiaratchi, University of Western Australia, and Erik van Sebille, Utrecht University

Great areas of our rubbish are known to form in parts of the Pacific and Atlantic oceans. But no such “garbage patch” has been found in the Southern Indian Ocean.

Our research – published recently in Journal of Geophysical Research: Oceans – looked at why that’s the case, and what happens to the rubbish that gets dumped in this particular area.

Every year, up to 15 million tonnes of plastic waste is estimated to make its way into the ocean through coastlines (about 12.5 million tonnes) and rivers (about 2.5 million tonnes). This amount is expected to double by 2025.




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Some of this waste sinks in the ocean, some is washed up on beaches, and some floats on the ocean surface, transported by currents.

The garbage patches

As plastic materials are extremely durable, floating plastic waste can travel great distances in the ocean. Some floating plastics collect in the centre of subtropical circulating currents known as gyres, between 20 to 40 degrees north and south, to create these garbage patches.

The Great Pacific Garbage Patch.
National Oceanic and Atmospheric Administration

Here, the ocean currents converge at the centre of the gyre and sink. But the floating plastic material remains at the surface, allowing it to concentrate in these regions.

The best known of these garbage patches is the Great Pacific Garbage Patch, which contains about 80,000 tonnes of plastic waste. As the National Oceanic and Atmospheric Administration points out, the “patches” are not actually clumped collections of easy-to-see debris, but concentrations of litter (mostly small pieces of floating plastic).

Similar, but smaller, patches exist in the North and South Atlantic Oceans and the South Pacific Ocean. In total, it is estimated that only 1% of all plastic waste that enters the ocean is trapped in the garbage patches. It is still a mystery what happens to the remaining 99% of plastic waste that has entered the ocean.

Rubbish in the Indian Ocean

Even less is known about what happens to plastic in the Indian Ocean, although it receives the largest input of plastic material globally.

For example, it has been estimated that up to 90% of the global riverine input of plastic waste originates from Asia. The input of plastics to the Southern Indian Ocean is mainly through Indonesia. The Australian contribution is small.

The major sources of riverine input of plastic material into the Indian Ocean.
The Ocean Cleanup, CC BY-NC-ND

The Indian Ocean has many unique characteristics compared with the other ocean basins. The most striking factor is the presence of the Asian continental landmass, which results in the absence of a northern ocean basin and generates monsoon winds.

As a result of the former, there is no gyre in the Northern Indian Ocean, and so there is no garbage patch. The latter results in reversing ocean surface currents.

The Indian and Pacific Oceans are connected through the Indonesian Archipelago, which allows for warmer, less salty water to be transported from the Pacific to the Indian via a phenomenon called the Indonesian Throughflow (see graphic, below).

Schematic currents and location of a leaky garbage patch in the southern Indian Ocean: Indonesian Throughflow (ITF), Leeuwin Current (LC), South Indian Counter Current (SICC), Agulhas Current (AC).
Author provided

This connection also results in the formation of the Leeuwin Current, a poleward (towards the South Pole) current that flows alongside Australia’s west coast.

As a result, the Southern Indian Ocean has poleward currents on both eastern and western margins of the ocean basin.

Also, the South Indian Counter Current flows eastwards across the entire width of the Southern Indian Ocean, through the centre of the subtropical gyre, from the southern tip of Madagascar to Australia.

The African continent ends at around 35 degrees south, which provides a connection between the southern Indian and Atlantic Oceans.

How to follow that rubbish

In contrast to other ocean basins, the Indian Ocean is under-sampled, with only a few measurements of plastic material available. As technology to remotely track plastics does not yet exist, we need to use indirect ways to determine the fate of plastic in the Indian Ocean.

We used information from more than 22,000 satellite-tracked surface drifting buoys that have been released all over the world’s oceans since 1979. This allowed us to simulate pathways of plastic waste globally, with an emphasis on the Indian Ocean.

Global simulated concentration of floating waste after 50 years.
Mirjam van der Mheen, Author provided

We found that unique characteristics of the Southern Indian Ocean transport floating plastics towards the ocean’s western side, where it leaks past South Africa into the South Atlantic Ocean.

Because of the Asian monsoon system, the southeast trade winds in the Southern Indian Ocean are stronger than the trade winds in the Pacific and Atlantic Oceans. These strong winds push floating plastic material further to the west in the Southern Indian Ocean than they do in the other oceans.

So the rubbish goes where?

This allows the floating plastic to leak more readily from the Southern Indian Ocean into the South Atlantic Ocean. All these factors contribute to an ill-defined garbage patch in the Southern Indian Ocean.

Simulated concentration of floating waste over 50 years in the Indian Ocean.

In the Northern Indian Ocean our simulations showed there may be an accumulation of waste in the Bay of Bengal.




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It is also likely that floating plastics will ultimately end up on beaches all around the Indian Ocean, transported by the reversing monsoon winds and currents. Which beaches will be most heavily affected is still unclear, and will probably depend on the monsoon season.

Our study shows that the atmospheric and oceanic attributes of the Indian Ocean are different to other ocean basins and that there may not be a concentrated garbage patch. Therefore the mystery of all the missing plastic is even greater in the Indian Ocean.The Conversation

Mirjam van der Mheen, PhD Candidate in Oceanography, University of Western Australia; Charitha Pattiaratchi, Professor of Coastal Oceanography, University of Western Australia, and Erik van Sebille, Associate Professor in Oceanography and Climate Change, Utrecht University

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

Mercury pollution from decades past may have been re-released by Tasmania’s bushfires



File 20190405 114905 1kz1fq7.jpg?ixlib=rb 1.1
Tasmania’s fires may have released mercury previously absorbed by trees.
AAP Image

Larissa Schneider, Australian National University; Kathryn Allen, University of Melbourne, and Simon Haberle, Australian National University

Tasmania’s bushfires may have resulted in the release of significant amounts of mercury from burnt trees into the atmosphere. Our research shows that industrial mercury pollution from decades past has been locked up in west Tasmanian trees.

Mercury occurs naturally in Earth’s crust. Over the past 200 years, industrial activities have mobilised mercury from the crust and released it into the atmosphere. As a consequence, atmospheric mercury concentrations are now three to four times higher than in the pre-industrialisation era.

Mining is the largest source of the global atmospheric mercury, accounting for 37% of mercury emissions. When Europeans first arrived in Australia, there was, of course, no Environmental Protection Act in place to limit emissions from industrial activities. In western Tasmania, where mining has occurred for more than a century, this meant mercury was being released without control into the local atmosphere until changes in technology, market conditions, and later, regulation, conspired to reduce emissions.




Read more:
Australia emits mercury at double the global average


Because mercury is also very persistent in the environment, past mining activity has generated a reservoir of mercury that could be released to the atmosphere under certain conditions. This is a concern because even small amounts of mercury may be toxic and may cause serious health problems. In particular, mercury can threaten the normal development of a child in utero and early in its life.

Tree rings can reveal past mercury contamination

How much mercury has been released into the Australian environment and when has remained largely unknown. However, in a new study we show how mercury levels in Tasmania have dramatically changed over the past 150 years due to mining practices. Long-lived Huon pine, endemic to western Tasmania, is one of the most efficient bioaccumulators of mercury in the world. This makes it a good proxy for tracking mercury emissions in western Tasmania. If concentrations of mercury in the atmosphere are high in a given year, this can be detected in the annual ring of Huon pine for that year.

Mercury pollution from past mining practices in western Tasmania has left a lasting environmental legacy. The sampled trees contained a significant reservoir of mercury that was taken up during the peak mining period in Queenstown. Changes in mercury concentrations in the annual rings of Huon pine are closely aligned with changes in mining practices in the region.

Increased concentrations coincide with the commencement of pyritic copper smelting in Queenstown in 1896. They peak between 1910 and 1920 when smelting was at its height. In 1922, concentrations begin to decline in parallel with the introduction of a new method to separate and concentrate ores. This method required only one small furnace instead of 11 large ones. In 1934, a new dust-collection apparatus was installed in the smelter’s chimney, coinciding with the further decrease in mercury concentrations in nearby Huon pine.

Temporal tree rings of Huon pine, revealing historical mercury pollution.
Author provided

Toxic elements or compounds taken up by vegetation can also be released back into the local environment. Bushfires that burn trees that have accumulated mercury may release this mercury as vapour, dust or fine ash, potentially exposing people and wildlife to the adverse effects of mercury. It is estimated that bushfires release 210,000kg of mercury into the global atmosphere each year. As these fires become more frequent and ferocious in Australia, mercury concentrations in the atmosphere are likely to increase. Mercury released by bushfires can persist in the atmosphere for a year, allowing for long-distance transportation depending on wind strength and direction. This means that mining activity from over a century ago may have regional implications in the near future. The Tasmanian fires in December-February burned almost 200,000 hectares, including areas around Queenstown.

It is not currently possible to know how much mercury has been released by these recent fires. Our results simply highlight the potential risk and the need to better understand the amount of mercury taken up by vegetation that may one day be released back to the atmosphere via bushfires.

Re-release of historical mercury emissions by bushfires.
Author provided



Read more:
Dry lightning has set Tasmania ablaze, and climate change makes it more likely to happen again


Although there is no simple way to remove bio-accumulated mercury from trees, the history of mercury contamination recorded in tree rings provides important lessons. Decreased uptake of mercury after upgrades to the Queenstown copper smelter operations demonstrates the positive impact that good management decisions can have on the amount of mercury released into the environment.

To control mercury emissions globally, the United Nations Environment Programme (UNEP) has developed the Minamata Convention on Mercury. Its primary goal is to protect human health and the environment from the negative effects of mercury. Australia has signed the convention and but has yet to ratify it. Once ratified, Australia would be required to record sources of mercury and quantify emissions, including those from bushfires.

But to do this, the government must first be able to identify environmental reservoirs of mercury. Our study, the first of its kind in the Southern Hemisphere, shows that the long-lived Huon pine can be used to for this purpose. Further work to determine what other tree species record atmospheric emissions of mercury and other toxic elements in other regions of Australia is required.The Conversation

Larissa Schneider, DECRA fellow, Australian National University; Kathryn Allen, Academic, Ecosystem and Forest Sciences, University of Melbourne, and Simon Haberle, Professor, Australian National University

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