Climate change is making ocean waves more powerful, threatening to erode many coastlines


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Thomas Mortlock, Macquarie University; Itxaso Odériz, Universidad Nacional Autónoma de México (UNAM); Nobuhito Mori, Kyoto University, and Rodolfo Silva, Universidad Nacional Autónoma de México (UNAM)Sea level rise isn’t the only way climate change will devastate the coast. Our research, published today, found it is also making waves more powerful, particularly in the Southern Hemisphere.

We plotted the trajectory of these stronger waves and found the coasts of South Australia and Western Australia, Pacific and Caribbean Islands, East Indonesia and Japan, and South Africa are already experiencing more powerful waves because of global warming.

This will compound the effects of sea level rise, putting low-lying island nations in the Pacific — such as Tuvalu, Kiribati and the Marshall Islands — in further danger, and changing how we manage coasts worldwide.

But it’s not too late to stop the worst effects — that is, if we drastically and urgently cut greenhouse gas emissions.

An energetic ocean

Since the 1970s, the ocean has absorbed more than 90% of the heat gained by the planet. This has a range of impacts, including longer and more frequent marine heatwaves, coral bleaching, and providing an energy source for more powerful storms.

Since at least the 1980s, wave power has increased worldwide as more heat is pumped into the ocean.
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But our focus was on how warming oceans boost wave power. We looked at wave conditions over the past 35 years, and found global wave power has increased since at least the 1980s, mostly concentrated in the Southern Hemisphere, as more energy is being pumped into the oceans in the form of heat.

And a more energetic ocean means larger wave heights and more erosive energy potential for coastlines in some parts of the world than before.




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Ocean waves have shaped Earth’s coastlines for millions of years. So any small, sustained changes in waves can have long-term consequences for coastal ecosystems and the people who rely on them.

Mangroves and salt marshes, for example, are particularly vulnerable to increases in wave energy when combined with sea level rise.

To escape, mangroves and marshes naturally migrate to higher ground. But when these ecosystems back onto urban areas, they have nowhere to go and die out. This process is known as “coastal squeeze”.

These ecosystems often provide a natural buffer to wave attack for low-lying coastal areas. So without these fringing ecosystems, the coastal communities behind them will be exposed to more wave energy and, potentially, higher erosion.

Mangrove forests are among the most imperilled ecosystems as sea levels rise and ocean waves crash harder against the coast.
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So why is this happening?

Ocean waves are generated by winds blowing along the ocean surface. And when the ocean absorbs heat, the sea surface warms, encouraging the warm air over the top of it to rise (this is called convection). This helps spin up atmospheric circulation and winds.

In other words, we come to a cascade of impacts: warmer sea surface temperatures bring about stronger winds, which alter global ocean wave conditions.




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Our research shows, in some parts of the world’s oceans, wave power is increasing because of stronger wind energy and the shift of westerly winds towards the poles. This is most noticeable in the tropical regions of the Atlantic and Pacific Oceans, and the subtropical regions of the Indian Ocean.

But not all changes in wave conditions are driven by ocean warming from human-caused climate change. Some areas of the world’s oceans are still more influenced by natural climate variability — such as El Niño and La Niña — than long-term ocean warming.

In general, it appears changes to wave conditions towards the equator are more driven by ocean warming from human-caused climate change, whereas changes to waves towards the poles remain more impacted by natural climate variability.

Ocean waves are generated by winds blowing across the ocean surface.
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How this could erode the coasts

While the response of coastlines to climate change is a complex interplay of many processes, waves remain the principal driver of change along many of the world’s open, sandy coastlines.

So how might coastlines respond to getting hit by more powerful waves? It generally depends on how much sand there is, and how, exactly, wave power increases.

For example, if there’s an increase in wave height, this may cause increased erosion. But if the waves become longer (a lengthening of the wave period), then this may have the opposite effect, by transporting sand from deeper water to help the coast keep pace with sea level rise.

Sandy beaches, including those around South Australia and Western Australia, may see greater risk of erosion in coming decades as wave power increases.
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For low-lying nations in areas of warming sea surface temperatures around the equator, higher waves – combined with sea level rise – poses an existential problem.

People in these nations may experience both sea level rise and increasing wave power on their coastlines, eroding land further up the beach and damaging property.
These areas should be regarded as coastal climate hotspots, where continued adaption or mitigation funding is needed.

It’s not too late

It’s not surprising for us to find the fingerprints of greenhouse warming in ocean waves and, consequentially, along our coastlines. Our study looked only at historical wave conditions and how these are already being impacted by climate change.

But if warming continues in line with current trends over the coming century, we can expect to see more significant changes in wave conditions along the world’s coasts than uncovered in our backward-looking research.

However, if we can mitigate greenhouse warming in line with the 2℃ Paris agreement, studies indicate we could still keep changes in wave patterns within the bounds of natural climate variability.




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Still, one thing is abundantly clear: the impacts of climate change on waves is not a thing of the future, and is already occurring in large parts of the world’s oceans.

The extent to which these changes continue and the risk this poses to global coastlines will be closely linked to decarbonisation efforts over the coming decades.

This story is part of Oceans 21

Our series on the global ocean opened with five in depth profiles. Look out for new articles on the state of our oceans in the lead up to the UN’s next climate conference, COP26. The series is brought to you by The Conversation’s international network.The Conversation

Thomas Mortlock, Senior Risk Scientist, Risk Frontiers, Adjunct Fellow, Macquarie University; Itxaso Odériz, Research assistant, Universidad Nacional Autónoma de México (UNAM); Nobuhito Mori, Professor, Kyoto University, and Rodolfo Silva, Professor, Universidad Nacional Autónoma de México (UNAM)

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

‘Green steel’ is hailed as the next big thing in Australian industry. Here’s what the hype is all about


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Jessica Allen, University of Newcastle and Tom Honeyands, University of NewcastleSteel is a major building block of our modern world, used to make everything from cutlery to bridges and wind turbines. But the way it’s made – using coal – is making climate change worse.

On average, almost two tonnes of carbon dioxide (CO₂) are emitted for every tonne of steel produced. This accounts for about 7% of global greenhouse gas emissions. Cleaning up steel production is clearly key to Earth’s low-carbon future.

Fortunately, a new path is emerging. So-called “green steel”, made using hydrogen rather than coal, represents a huge opportunity for Australia. It would boost our exports, help offset inevitable job losses in the fossil fuel industry and go a long way to tackling climate change.

Australia’s abundant and cheap wind and solar resources mean we’re well placed to produce the hydrogen a green steel industry needs. So let’s take a look at how green steel is made, and the challenges ahead.

Steel workers at plant
A green steel industry would give Australia a slice of the low-emissions manufacturing boom.
Daniel Munoz/AAP

Steeling for change

Steel-making requires stripping oxygen from iron ore to produce pure iron metal. In traditional steel-making, this is done using coal or natural gas in a process that releases CO₂. In green steel production, hydrogen made from renewable energy replaces fossil fuels.

Australia exports almost 900 million tonnes of iron ore each year, but only makes 5.5 million tonnes of steel. This means we have great capacity to ramp up steel production.

A Grattan Institute report last year found if Australia captured about 6.5% of the global steel market, this could generate about A$65 billion in annual export revenue and create 25,000 manufacturing jobs in Queensland and New South Wales.

Steel-making is a complex process and is primarily achieved via one of three processes. Each of them, in theory, can be adapted to produce green steel. We examine each process below.




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Roll of red-hot steel
Steel-making is a complex process.
Dean Lewins/AAP

1. Blast furnace

Globally, about 70% of steel is produced using the blast furnace method.

As part of this process, processed coal (also known as coke) is used in the main body of the furnace. It acts as a physical support structure for materials entering and leaving the furnace, among other functions. It’s also partially burnt at the bottom of the furnace to both produce heat and make carbon monoxide, which strips oxygen from iron ore leaving metallic iron.

This coal-driven process leads to CO₂ emissions. It’s feasible to replace a portion of the carbon monoxide with hydrogen. The hydrogen can strip oxygen away from the ore, generating water instead of CO₂. This requires renewable electricity to produce green hydrogen.

And hydrogen cannot replace carbon monoxide at a ratio of 1:1. If hydrogen is used, the blast furnace needs more externally added heat to keep the temperature high, compared with the coal method.

More importantly, solid coal in the main body of the furnace cannot be replaced with hydrogen. Some alternatives have been developed, involving biomass – a fuel developed from living organisms – blended with coal.

But sourcing biomass sustainably and at scale would be a challenge. And this process would still likely create some fossil-fuel derived emissions. So to ensure the process is “green”, these emissions would have to be captured and stored – a technology which is currently expensive and unproven at scale.




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Smoke billows from steel plant
Producing steel using the blast furnace method produces substantial emissions.
Dean Lewins/AAP

2. Recycled steel

Around 30% of the world’s steel is made from recycled steel. Steel has one of the highest recycling rates of any material.

Steel recycling is mainly done in arc furnaces, driven by electricity. Each tonne of steel produced using this method produces about 0.4 tonnes of CO₂ – mostly due to emissions produced by burning fossil fuels for electricity generation. If the electricity was produced from renewable sources, the CO₂ output would be greatly reduced.

But steel cannot continuously be recycled. After a while, unwanted elements such as copper, nickel and tin begin to accumulate in the steel, reducing its quality. Also, steel has a long lifetime and low turnover rate. This means recycled steel cannot meet all steel demand, and some new steel must be produced.

3. Direct reduced iron

“Direct reduced iron” (DRI) technology often uses methane gas to produce hydrogen and carbon monoxide, which are then used to turn iron ore into iron. This method still creates CO₂ emissions, and requires more electricity than the blast furnace method. However its overall emission intensity can be substantially lower.

The method currently accounts for less than 5% of production, and offers the greatest opportunity for using green hydrogen.

Up to 70% of the hydrogen derived from methane could be replaced with green hydrogen without having to modify the production process too much. However work on using 100% green hydrogen in this method is ongoing.




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workers walk past rolls of finished steel
New steel must be produced because not enough steel is available for recycling.
Dean Lewins/AAP

Becoming a green steel superpower

The green steel transition won’t happen overnight and significant challenges remain.

Cheap, large-scale green hydrogen and renewable electricity will be required. And even if green hydrogen is used, to achieve net-zero emissions the blast furnace method will still require carbon-capture and storage technologies – and so too will DRI, for the time being.

Private sector investment is needed to create a global-scale export industry. Australian governments also have a big role to play, in building skills and capability, helping workers retrain, funding research and coordinating land-use planning.

Revolutionising Australia’s steel industry is a daunting task. But if we play our cards right, Australia can be a major player in the green manufacturing revolution.The Conversation

Jessica Allen, Senior Lecturer and DECRA Fellow, University of Newcastle and Tom Honeyands, Director, Centre for Ironmaking Materials Research, University of Newcastle

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

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


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

This announcement is disappointing, but not surprising.

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

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

Tackling a ‘collective action’ problem

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

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

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

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

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




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

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

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

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

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

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

Joining the climate club

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




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

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

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

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




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

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

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

Like a stack of dominoes

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

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




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

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

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

Katie Steele, Associate Professor in Philosophy, Australian National University

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

Four seismic climate wins show Big Oil, Gas and Coal are running out of places to hide


Peter Dejong/AP

Jacqueline Peel, The University of Melbourne; Ben Neville, The University of Melbourne, and Rebekkah Markey-Towler, The University of MelbourneThree global fossil fuel giants have just suffered embarrassing rebukes over their inadequate action on climate change. Collectively, the developments show how courts, and frustrated investors, are increasingly willing to force companies to reduce their carbon dioxide pollution quickly.

A Dutch court ordered Royal Dutch Shell to slash its greenhouse emissions, and 61% of Chevron shareholders backed a resolution to force that company to do the same. And in an upset at Exxon Mobil, an activist hedge fund won two seats on the company’s board.

The string of wins was followed in Australia on Thursday by a court ruling that the federal environment minister, when deciding whether or not to approve a new coal mine, owes a duty of care to young people to avoid causing them personal injury from climate change.

The court rulings are particularly significant. Courts have often been reluctant to interfere in what is viewed as an issue best left to policymakers. These recent judgements, and others, suggest courts are more prepared to scrutinise emissions reduction by businesses and – in the case of the Dutch court – order them to do more.

Shell, Chevron and Exxon logos
The wins for climate action put big polluters on notice.
AP

Court warns of ‘irreversible consequences’

In a world-first ruling, a Hague court ordered oil and gas giant Shell to reduce CO₂ emissions by 45% by 2030, relative to 2019 levels. The court noted Shell had no emissions-reduction targets to 2030, and its policies to 2050 were “rather intangible, undefined and non-binding”.

The case was brought by climate activist and human rights groups. The court found climate change due to CO₂ emissions “has serious and irreversible consequences” and threatened the human “right to life”. It also found Shell was responsible for so-called “Scope 3” emissions generated by its customers and suppliers.

The Chevron upset involved an investor revolt. Some 61% of shareholders supported a resolution calling for Chevron to substantially reduce Scope 3 emissions generated by the use of its oil and gas.

And last week, shareholders of ExxonMobil, one of the world’s biggest corporate greenhouse gas emitters, forced a dramatic management shakeup. An activist hedge fund, Engine No. 1, won two, and potentially three, places on the company’s 12-person board.

Engine No. 1 explicitly links Exxon’s patchy economic performance to a failure to invest in low-carbon technologies.




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oil rig
The court said Shell’s emissions reduction efforts were ‘rather intangible’.
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Climate-savvy shareholders unite

As human activity causes Earth’s atmosphere to warm, large fossil fuel companies are under increasing pressure to act.

A mere 20 companies have contributed 493 billion tonnes of CO₂ and methane to the atmosphere, primarily from the burning of their oil, coal and gas. This equates to 35% of all global greenhouse gas emissions since 1965.

Shareholders – many concerned by the financial risks of climate change – are leading the corporate accountability push. The Climate Action 100+ initiative is a leading example.

It involves more than 400 investors with more than A$35 trillion in assets under management, who work with companies to reduce emissions, and improve governance and climate-related financial disclosures. Similar movements are emerging worldwide.

Shareholders in Australia are also stepping up engagement with companies over climate change.

Last year, shareholder resolutions on climate change were put to Santos and Woodside. While neither resolution achieved the 75% support needed to pass, both received unprecedented levels of support – 43.39% and 50.16% of the vote, respectively.

And in May 2021, Rio Tinto became the first Australian board to publicly back shareholder resolutions on climate change, which subsequently passed with 99% support.




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Rio Tinto executives
The Rio Tinto board backed a shareholder resolution on climate change.
Brendan Esposito/AAP

The litigation trend

To date, the question of whether corporate polluters can be legally forced to reduce greenhouse emissions has remained unanswered. While fossil fuel companies have faced a string of climate lawsuits in the United States and Europe, courts have often dismissed the claims on procedural grounds.

Cases brought against governments have been more successful. In 2019, for example, the Dutch Supreme Court affirmed the government has a legal duty to prevent dangerous climate change.

The decision against Shell is significant, and sends a clear signal that corporations can be held legally responsible for greenhouse pollution.

Shell has previously argued it can only reduce its absolute emissions by shrinking its business. The recent case highlights how such companies may have to quickly find new forms of revenue, or face legal liability.

It’s unlikely we’ll see identical litigation in Australia, because our laws are different to those in the Netherlands. But the Shell case is emblematic of a broader trend of climate litigation being brought to challenge corporate polluters.

This includes the case decided on Thursday involving young people opposed to a company’s coal mine expansion, and Australian cases arguing for greater disclosure of climate risk by corporations, banks and super funds.




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teenagers involved in case
The case brought against the Australian government by a group of teenagers is part of a growing trend towards climate litigation.
Supplied

Change is nigh

Oil and gas companies often argue Scope 3 emissions are not their responsibility, because they don’t control how customers use their products. The Shell finding and shareholder action against Chevron suggest this claim may hold little sway with courts or shareholders in future.

The Shell case may also set off a global avalanche of copycat litigation. In Australia, legal experts have noted the turning tide, and warned is it’s only a matter of time before directors who fail to act on climate change face litigation.

Clearly, a seismic shift is looming, in which corporations will be forced to take greater responsibility for climate harms. These recent developments should act as a wake-up call for oil, gas and coal companies, in Australia and around the world.The Conversation

Jacqueline Peel, Professor of Environmental and Climate Law, The University of Melbourne; Ben Neville, Senior Lecturer and Program Director of the Master of Commerce, The University of Melbourne, and Rebekkah Markey-Towler, Research fellow, Melbourne Climate Futures, The University of Melbourne

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

Beautiful, rare ‘purple cauliflower’ coral off NSW coast may be extinct within 10 years


Author supplied

Meryl Larkin, Southern Cross University; David Harasti, Southern Cross University; Steve Smith, Southern Cross University, and Tom R DavisWhen we think of Australia’s threatened corals, the Great Barrier Reef probably springs to mind. But elsewhere, coral species are also struggling – including a rare type known as “cauliflower soft coral” which is, sadly, on the brink of extinction.

This species, Dendronephthya australis, looks like a purple cauliflower due to its pink-lilac stems and branches, crowned with white polyps.

The coral primarily occurs at only a few sites in Port Stephens, New South Wales, and is a magnet for divers and underwater photographers. But sand movements, boating and fishing have reduced the species’ population dramatically.

Recent flooding in NSW compounded the problem – in fact, it may have reduced the remaining coral population by 90%. Our recent research found cauliflower soft coral may become extinct in the next decade unless we urgently protect and restore it.

An ovulid on a cauliflower coral colony. Such coral may be extinct within a decade.
Author supplied

Lilac underwater gardens

Cauliflower soft corals are predominantly found in estuarine environments on sandy seabeds with high current flow. They rely on tidal currents to transport plankton on which they feed.

The species is most commonly found in the Port Stephens estuary, about 200 kilometres north of Sydney. It’s also found in the Brisbane Water estuary in NSW, and has been found sporadically in other locations south to Jervis Bay.

The coral colonies form aggregations or “gardens”. At Port Stephens, these gardens are the preferred habitat for the endangered White’s seahorse and protected species of pipefish. They also support juvenile Australasian snapper, an important species for commercial and recreational fishers.

In recent months, the cauliflower soft coral has been listed as endangered in NSW and nationally.




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An alarming decline

Scientists first mapped the distribution of the cauliflower soft coral in 2011. They found none of the biggest colonies in the Port Stephens estuary were protected by “no take” zones – areas where fishing and other extractive activities are banned.

In research in 2016, we found a sharp decline in the extent and distribution of cauliflower soft coral.

Our recent study examined the problem in more detail. It involved mapping the southern shoreline of Port Stephens, using an underwater camera towed by a vessel.

We found the cauliflower soft coral in the Port Stephens estuary has declined by almost 70% over just eight years. It now occurs over 9,300 square metres – down from 28,600 square metres in 2011.

Our subsequent modelling sought to identify what was driving the corals’ decline. We found a correlation between coral loss and sand movements over the last decade.

Human changes to shorelines, such as marina developments, have changed the dynamic of currents across the estuary. For example, previous research found a large influx of sand from the western end of Shoal Bay smothered cauliflower soft coral colonies at two nearby locations. As of 2018, those colonies had disappeared completely.

While diving as part of the project, we identified other causes of damage to the coral. Dropped boat anchors and the installation of moorings had damaged some colonies. Others were injured after becoming entangled in fishing line.

It is possible that disease, and pollution or other water quality issues, may also be contributing to the species’ decline.

Fishing line damaging a colony of cauliflower soft coral in Port Stephens.
Author supplied

Then the floods hit

Some 18 months after our most recent mapping, cauliflower soft corals suffered yet another blow. Major flooding in NSW in March this year caused a massive amount of fresh water to discharge from the Karuah River into the Port Stephens estuary, where sea water is dominant. Fresh water can kill cauliflower soft corals.

Following the floods, we conducted exploratory dives at locations where the cauliflower soft corals had been thriving at Port Stephens. We found much of the coral had disintegrated and disappeared. In fact, we estimated as much as 90% of the remaining cauliflower soft coral population was gone.

We plan to remap the estuary in the coming weeks, and feel confident our initial estimates will be close to the mark. If so, this means less than 5% of the species area mapped in 2011 now remains.

The floods also devastated kelp forests and other canopy-forming habitats in the estuary. Further work by scientists at the NSW Department of Primary Industries is underway to quantify these losses and monitor the recovery.




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Monitoring of existing cauliflower coral aggregations is ongoing.
Author supplied

Urgent work required

The cauliflower soft coral urgently needs protecting. This will require ongoing, coordinated research and management.

Clearly, action must be taken to reduce threats such as anchoring, fishing, and development that may magnify sand movement.

Best-practice rehabilitation is also needed. This may involve rearing the coral off-site and transplanting it into suitable habitat. Such trials at Port Stephens have shown promising signs.

Human activities are causing species loss at an alarming rate. We must do everything in our power to prevent the extinction of the cauliflower soft coral, and other threatened species, to preserve the balance of nature and its ecosystems.




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The Conversation


Meryl Larkin, PhD Candidate, Southern Cross University; David Harasti, Adjunct assistant professor, Southern Cross University; Steve Smith, Professor of Marine Science, National Marine Science Centre, Southern Cross University, and Tom R Davis, Research Scientist – Marine Climate Change

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

If you’re planning to hike this winter, invest in the right gear. Being unprepared for Australia’s harsh terrain can be deadly


Vanessa Adams, University of Tasmania; Jason Byrne, University of Tasmania, and Noelle Nemeth, University of TasmaniaTwo years ago, emergency workers rescued a hiker in Cradle Mountain-Lake St Clair National Park. He had spent nine days in his tent in freezing weather with dangerous blizzards, trying to keep dry from infiltrating snow and rain.

Because he was an experienced and prepared hiker, he had the skills and gear needed to keep himself safe and relatively warm until rescuers could find him. His preparedness ultimately led to his survival.

Such experiences, however, don’t always have happy endings.

Of the hikers, trekkers and bushwalkers who need rescuing from Australia’s harsh wilderness each year, a small proportion never make it back alive. And as we head into winter, the likelihood of accidents increases, especially in places like Tasmania.

Our recent research on hikers in Tasmania shows just how important preparedness is to prevent injuries and deaths. So let’s look at what it means to be prepared for a hike and who’s most at risk.

Slips, drops, hypothermia

Tasmania is quickly becoming known worldwide as a hiking destination, with Cradle Mountain National Park the crown jewel, from short two-hour walks to the multi-day Overland track.

In 2017-18, an estimated 280,000 people visited Cradle Mountain, and 9,000 hikers completed the Overland track between October and May.

Two hikers on a grassland trail
The Tassie wilderness provides awe-inspiring but physically demanding hikes for visitors.
Noelle Nemeth, Author provided

But in winter, Tasmania’s weather conditions can change rapidly, particularly in alpine areas that draw people in with the promise of snow-capped mountains. One hour it can be clear and sunny. The next, bad weather can worsen into a blizzard.

The island’s sometimes severe weather means risks are amplified. These can include getting lost, running out of food or water while sheltering, and having an accident such as falling from steep and slippery terrain.




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Across Tasmania, bushwalker rescues fluctuate substantially by year, from lows of six (2018) to highs of 44 (2019).

Of the recent hiker deaths in Tasmania, some have been due to falls from great heights, while others are attributed to a lack of preparation and appropriate gear causing hypothermia.

Hypothermia is life threatening. This video explains how you can be prepared in Tasmania’s parks and reserves.

For park management agencies, rescuing injured hikers or recovering the deceased can be dangerous and expensive. Estimated rescue costs range from a few hundred dollars to tens of thousands of dollars per incident.

At times, bad weather conditions means rescue agencies can’t access sites. They have to make the challenging decision not to respond to rescue calls, to protect the lives of volunteers and rescue staff.

What is preparedness and why does it matter?

Preparedness is about providing yourself with the necessary resources to safely tackle unexpected issues that may arise.

How prepared you are can be the difference between severe injury or death, and survival. We define preparedness as the process of:

  • packing essential clothing and equipment
  • conducting pre-planning and familiarisation with a destination (what are the weather conditions, or trail conditions like?)
  • self-assessment of capabilities (what’s your fitness level, and what are your wilderness knowledge and skills like?)
  • notifying others about your travel intentions.
Hiking boots overlooking a lake in Cradle Mountain
Wearing the right shoes on your next hike can save your life.
Shutterstock

Some hikers are better prepared than others

Our research surveyed overnight hikers in Tasmania. And we found a lack of preparedness is related to people’s backgrounds (such as age and sex) and behavioural traits (such as risk taking).

Young men, for example, appear more likely to take risks, overestimating their skills and experience. Some tourist groups, who are unfamiliar with local weather conditions and landscapes, are also at higher risk.

In many accidents, inadequate clothing or footwear is a culprit, such as lack of woollen base layers, hats and gloves, and waterproof outer layers. This can result in hypothermia, frostbite, falls and other major problems.




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We were surprised by what many hikers didn’t carry, including maps, compasses, whistles, and first aid kits — essential items for all hikers. Some told us they didn’t own that equipment, others thought it was unnecessary.

People in a tour group were less likely to carry food, a first aid kit and safety items, believing their guide would carry it for them. But if group members become separated, the consequences can be fatal.

Hiker beside an orange tent
Maps, compasses, whistles and first aid kits are essential on every hike.
Shutterstock

Our research also suggests hikers out for day trips or shorter walks, appear to feel there’s less risk and seem less prepared than if they were doing a longer trip.

They’re unlikely to take an emergency position indicating radio beacon (EPIRB) or personal locator beacon (PLB), which can send a distress signal and alert rescuers to your location in places with no phone reception. They may also wear sport shoes instead of hiking boots, and some don’t carry essential items for winter walking, such as a waterproof jacket or tent.

Being prepared with the right gear and experience is important regardless of how long you plan on being out. The reality is weather conditions can change suddenly, even if you’re not out for very long.

So how can you be better prepared?

In response to past hiker deaths, coronial inquests have identified better education, improved visitor management and safety measures as possible solutions.

But we’ve also identified a simple, but likely effective solution that could supplement a continued lack of appropriate gear: the use of a “gear library”.

A gear library would be set up at visitor centres where you’re usually expected to start hikes and would allow people to hire speciality gear items, such as personal safety devices (EPIRB, PLB). These can usually cost more than $200, but would be substantially cheaper in a gear library, ensuring rescue workers are notified and can find you after an accident.




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It’s also important to keep a checklist to pack essential items. Some key items include:

  • adequate supply of food and water, including contingency items for unexpected additional days hiking because of bad weather
  • warm clothes, such as a waterproof jacket with hood and storm front, waterproof over-trousers, sturdy walking boots and warm clothing (a fleece or woollen jumper, thermal base layers, hat and gloves)
  • appropriate footwear, such as hiking boots
  • a tent for overnight hikes
  • a first aid kit
  • a torch.

There are plenty of resources for people seeking information about how best to prepare for their bushwalk, including national park visitor centres, Westpac Rescue Tas and the Parks and Wildlife Tasmania website. These websites provide essential bushwalking guides on what to pack and how to prepare for bushwalking.

Anyone can safely enjoy a good day out in the Tasmanian wilderness — it’s beautiful, but can also be deadly. You can never be too prepared.




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The Conversation


Vanessa Adams, Senior Lecturer, Discipline of Geography and Spatial Sciences, University of Tasmania; Jason Byrne, Professor of Human Geography and Planning, University of Tasmania, and Noelle Nemeth, Master’s Research Student, University of Tasmania

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

Willow trees are notorious pests. But for freshwater animals, they could be unlikely climate heroes


Willow invasion on Happy Valley Creek in north east Victoria.
Author provided; Happy Valley Creek, Victoria, Author provided

Paul McInerney, CSIRO and Tanya Doody, CSIROClimate change will make Australia hotter and drier in future, and we’re starting to see the dangerous consequences of this in our rivers, lakes and streams.

As waters warm and flow patterns alter, the animals who call these waterways home may struggle to survive. Many are ectotherms — meaning that unlike humans, these animals can’t regulate their body temperature, putting them at the mercy of ambient water temperature. And for animals that have evolved in cold water, such as some native crayfish, increased water temperatures can be lethal.

Our new research paper calls for a (possibly controversial) solution: take advantage of willow trees growing along the banks. They can create cool, shady refuges in these warming waterways.

Willows are not native and, in many places, are an invasive weed. But for temperature-sensitive animals, their dense, leafy canopy may make willows the lesser of two evils in a warming climate.

The lesser evil

Willows belong to the genus Salix, and are natives of the northern hemisphere. They were introduced to Australia in the 19th century first as ornamental plants, then later planted to help stabilise river banks to combat erosion.

Today, they’re considered noxious weeds in Australia, South America and southern Africa, are highly invasive and have spread along waterways throughout temperate Australia.

Willows along waterways can prevent light from entering streams and cool water temperature.
Author provided; Yackandandah Creek, Victoria

The harms willows inflict on aquatic ecosystems are well documented. For example, they alter energy dynamics in streams by dropping all their leaves into the water at once, which can reduce water quality and the amount of food for animals.

Dense shading in summer reduces the amount of algae (an important food source) growing on surfaces in streams. Willows also out-shade and use more water than native plants, stopping them from re-colonising.

These reasons are why governments invest in removing willows from our waterways. But what if willows offer some benefits to their invaded ecosystems, too?

Freshwater wildlife in peril

As far as we know, the presence of willows hasn’t caused any extinctions. But in coming years, we can expect to see more animal extinctions due to temperature increases from climate change.

To deal with climate change, temperature-sensitive animals are left with two options: either migrate upstream to cooler water or adapt to warmer water. Both alternatives are problematic.

Willow trees on a river bank
Willow trees can out-shade native plants and stop them from re-colonising.
Shutterstock

Some animals, such as two-spined blackfish, aren’t well suited to (or potentially even capable of) long distance travel to cooler water. And many of our rivers have barriers, such as dams, weirs and waterfalls, making migration impossible.

If animals stay put, Australia’s climate is now warming at such a fast rate, some may struggle to adapt quickly enough. The critically endangered barred galaxias is another cool water adapted fish unlikely to successfully migrate to other habitats to escape warming climate, but remains at risk if it doesn’t.




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To give wildlife a fighting chance at survival, we need to consider a patchwork of new and alternative approaches to stream management, such as creating “climatic refugia”. These are places where local climate is cooler than the regional climate, providing areas animals can escape to when temperatures get extreme.

Warmer temperatures may cause the populations of some freshwater species, such as the Murray River turtle, to grow.
Author provided

Trees and shrubs growing along the edges of streams (riparian vegetation) do this when they shade the water surface, helping to mediate water temperature.

This could make willows a useful tool for natural resource managers as we see increases in extreme heat days.

Happy Valley Creek

For our research paper, we use a case study from north-east Victoria to illustrate how dense willow invasions can reduce stream water temperature and create climatic refugia.




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We logged water temperature in Happy Valley Creek at three locations: at an upstream native forested site, a midstream site with no vegetation, and a downstream site that was heavily shaded by invasive willows.

We expected water temperature to increase with distance downstream as it moves from cool upland areas to warmer lowland areas. Instead, we found the water temperature at the willow shaded site could be a few degrees cooler than the midstream site, particularly during periods of extreme heat.

Fish among rocks
Some animals, like the two-spined blackfish, are unlikley to migrate to cooler waters.
Alan Couch/Wikimedia, CC BY-SA

Many streams are fringed by native vegetation that provide comparable heat protection to animals as willows, and we should protect these from willow invasion.

But in locations where willow removal activities are unlikely to be successful in the long-term, it may be better to prioritise willow removal elsewhere. For example, if willows can’t be removed from upstream catchments, they’ll continue to recolonise downstream. And if there’s no funding for follow-up activities, willows may re-establish following removal.

Where willows are rampant, they may already be protecting populations of heat-sensitive animals from temperature extremes. Removing them could have unintended consequences for such animals.

An absence of shade from bank-side vegetation can increase stream temperatures.
Author provided; Happy Valley Creek, Victoria

What’s the end goal?

It’s important to clarify we’re not suggesting willow removal activities should stop to prevent further widespread invasion. But as our climate changes, we need to objectively consider what ecosystems will be sustainable in the future, and prioritise our restoration efforts accordingly.

We need to decide what state we’re trying to manage our ecosystems to — the likely endpoint.




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Given current river regulations, land-use and changing climate, restoring all ecosystems to a pre–European state may not be sustainable or even possible at this point.

For willow-dominated, degraded catchments, there may be more value in promoting willows as refuges from the temperature extremes of climate change, rather than pursuing an ideal that may not even be possible.The Conversation

Paul McInerney, Research scientist, CSIRO and Tanya Doody, Principle Research Scientist, CSIRO, CSIRO

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