Under climate change, winter will be the best time for bush burn-offs – and that could be bad news for public health


Giovanni Di Virgilio, UNSW; Annette Hirsch, UNSW; Hamish Clarke, University of Wollongong; Jason Evans, UNSW; Jason Sharples, UNSW, and Melissa Hart, UNSW

At the height of last summer’s fires, some commentators claimed “greenies” were preventing hazard reduction burns – also known as prescribed burns – in cooler months. They argued that such burns would have reduced the bushfire intensity.

Fire experts repeatedly dismissed these claims. As then NSW Rural Fire Service Commissioner Shane Fitzsimmons noted in January this year, the number of available days to carry out prescribed burns had reduced because climate change was altering the weather and causing longer fire seasons.




Read more:
How does bushfire smoke affect our health? 6 things you need to know


This public conversation led our research team to ask: if climate change continues at its current rate, how will this change the days suitable for prescribed burning?

Our results, published today, were unexpected. Climate change may actually increase the number of burn days in some places, but the windows of opportunity will shift towards winter months. The bad news is that burning during these months potentially increases the public health impacts of smoke.

A hot debate

Hazard reduction involves removing vegetation that could otherwise fuel a fire, including burning under controlled conditions. But its effectiveness to subdue or prevent fires is often debated in the scientific community.

Commissioner Fitzsimmons weighs in on a national debate about hazard-reduction burns.

Those with experience on fire grounds, including Fitzsimmons, say it’s an important factor in fire management, but “not a pancea”.

Despite the debate, it’s clear hazard reduction burning will continue to be an important part of bushfire risk management in coming decades.




Read more:
The burn legacy: why the science on hazard reduction is contested


Modelling future weather

Before conducting prescribed burns, firefighting agencies consider factors such as vegetation type, proximity to property, desired rate of spread and possible smoke dispersal over populated areas. But we wanted to distil our investigation down to daily weather factors.

We reduced those factors to five key components. These were maximum temperature, relative humidity, wind speed, fuel moisture and the McArthur forest fire danger index (the index used to forecast fire danger in southeast Australia).

We looked at these elements on prescribed burning days between 2004-2015. We then used climate models to simulate how the conditions would change with global warming over southeast Australia, relative to a baseline historical 20-year period for 1990-2009.

To make a valid 20-year comparison, we compared the historical period to a modelled period from 2060-2079, assuming emissions continue to rise at their current pace.

A controlled burn in bushland, with small flames and lots of smoke.
Under global warming, suitable conditions for prescribed burns will be shifted to late winter and early spring in many places.
Shutterstock

Surprisingly, we found, with one regional exception, the number of days suitable for prescribed burning did not change. And in many places, the number increased.

As the fire season lengthened under a warming climate, the number of days suitable for burning just shifted from autumn to winter.

Shifting seasons

Our research indicated that by 2060 there’ll be fewer prescribed burning days during March, April and May. These are the months when most burning happens now.

But there will be significantly more opportunities for burning days from June to October. This is because the conditions that make for a good day for prescribed burning – such as mild and still days – start to shift to winter. Today, weather in these months is unsuitable for conducting burns.

Interestingly, these results aren’t uniform across southeast Australia. For example, much of the Australian east coast and South Australia would see seasonal shifts in burning windows, with around 50% fewer burning days in March to May.

Much of Victoria and in particular the southern regions saw an increase in burning windows during April to May and, in some parts of the state, through September and October as well.

Only the east Queensland coast would see a total reduction in prescribed burn days from April to October.

The smoke trap

This may be good news for firefighters and those agencies who depend on prescribed burning as a key tool in bushfire prevention. But, as so often is the case with climate change, it’s not that simple.

A byproduct of prescribed burning is smoke, and it’s a very significant health issue.

Last year, research showed global warming will strengthen an atmospheric layer that traps pollution close to the land surface, known as the “inversion layer”. This will happen in the years 2060-79, relative to 1990-2009 – especially during winter.




Read more:
The smoke from autumn burn-offs could make coronavirus symptoms worse. It’s not worth the risk


Unfortunately, the conditions that create inversion layers – including cool, still air – correspond with conditions suitable for prescribed burning.

For asthmatics and those sensitive to air pollution, smokier burn days could make winter months more difficult and add further stress to the health system.

It also creates an additional challenge for firefighting agencies, which must already consider whether smoke will linger close to the surface and potentially drift into populated regions during prescribed burns.

This is just one factor our firefighting agencies will need to face in the future as bushfire risk management becomes more complex and challenging under climate change.




Read more:
How does bushfire smoke affect our health? 6 things you need to know


The Conversation


Giovanni Di Virgilio, Research associate, UNSW; Annette Hirsch, Post Doctoral Research Fellow, UNSW; Hamish Clarke, Research Fellow, University of Wollongong; Jason Evans, Professor, UNSW; Jason Sharples, Professor of Bushfire Dynamics, School of Science, UNSW Canberra, UNSW, and Melissa Hart, Graduate Director, ARC Centre of Excellence for Climate Extremes, UNSW

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

The mystery of the Top End’s vanishing wildlife, and the unexpected culprits



A brush-tailed rabbit-rat, one of the small mammals disappearing in northern Australia.
Cara Penton, Author provided

Alyson Stobo-Wilson, Charles Darwin University; Brett Murphy, Charles Darwin University; Graeme Gillespie, University of Melbourne; Jaana Dielenberg, The University of Queensland, and John Woinarski, Charles Darwin University

Only a few decades ago, encountering a bandicoot or quoll around your campsite in the evening was a common and delightful experience across the Top End. Sadly, our campsites are now far less lively.

Northern Australia’s vast uncleared savannas were once considered a crucial safe haven for many species that have suffered severe declines elsewhere. But over the last 30 years, small native mammals (weighing up to five kilograms) have been mysteriously vanishing across the region.




Read more:
Scientists and national park managers are failing northern Australia’s vanishing mammals


The reason why the Top End’s mammals have declined so severely has long been unknown, leaving scientists and conservation managers at a loss as to how to stop and reverse this tragic trend.

The author smiles at an adorable glider in a little blanket she's holding.
Alyson Stobo-Wilson with a savanna glider. Gliders are among the mammals rapidly declining in northern Australia.
Alyson Stobo-Wilson, Author provided

Our major new study helps unravel this longstanding mystery. We found that the collective influence of feral livestock — such as buffaloes, horses, cattle and donkeys — has been largely underestimated. Even at quite low numbers, feral livestock can have a big impact on our high-value conservation areas and the wildlife they support.

The race for solutions

In 2010, Kakadu National Park conducted a pivotal study on Top End mammals. It found that between 1996 and 2009, the number of native mammal species at survey sites had halved, and the number of individual animals dropped by more than two-thirds. Similar trends have since been observed elsewhere across the Top End.

Given the scale and speed of the mammal declines, the need to find effective solutions is increasingly urgent. It has become a key focus of conservation managers and scientists alike.

The list of potential causes includes inappropriate fire regimes, feral cats, cane toads, feral livestock, and invasive weeds.

Many small and medium-sized mammals are in rapid decline in northern Australia.

With limited resources, it’s essential to know which threats to focus on. This is where our study has delivered a major breakthrough.

We looked for patterns of where species have been lost and where they are hanging on. With the help of helicopters to reach many remote areas, we used more than 1,500 “camera traps” (motion-sensor cameras to record mammals) and almost 7,500 animal traps (such as caged traps) to survey 300 sites across the national parks, private conservation reserves and Indigenous lands of the Top End.

A new spotlight on feral livestock

We found most parts of the Top End have very few native mammals left. The isolated areas where mammals are persisting have retained good-quality habitat, with a greater variety of plant species and dense shrubs and grasses.

This habitat provides more shelter and food for native mammals, and has fewer cats and dingoes, which hunt more efficiently in open areas. In contrast, sites with degraded habitat have much less food and shelter available, and native mammals are more exposed to predators.

Six dark coloured horses roam among sparse trees in the Top End.
Feral horses can overgraze and trample over habitat, making it far less suitable for small native mammals.
Jaana Dielenberg, Author provided

Across northern Australia, habitat quality is primarily driven by two factors: bushfires and introduced livestock, either farmed or feral.

Our surveys revealed that areas with more feral livestock have fewer native mammals. This highlights that the role of feral livestock in the Top End’s mammal declines has previously been underestimated.

Even at relatively low densities, feral livestock are detrimental to small mammals. Through overgrazing and trampling, they degrade habitat and reduce the availability of food and shelter for native mammals.




Read more:
The world’s best fire management system is in northern Australia, and it’s led by Indigenous land managers


Frequent, intense fires also play a big role. Australia’s tropical savannas are among the most fire-prone on Earth, but fires that are too frequent, too hot and too extensive remove critical food and shelter.

Yet, even if land managers can manage fires to protect biodiversity, for example by reducing the occurrence of large, intense fires, the presence of feral livestock will continue to impede native mammal recovery.

A wild buffalo walks over grass, in front of trees.
Even small numbers of feral livestock can play a big role in native mammal declines.
Northern Territory Government, Author provided

A new way to manage cats

Cats have helped drive more than 20 Australian mammals to extinction. So it’s not surprising we found fewer native mammals at our sample sites where there were more cats.

However, our results suggest the best way to manage the impact of cats in this region may not be to simply kill cats, which is notoriously difficult across vast, remote landscapes. Instead, it may be more effective to manage habitat better, tipping the balance in favour of native mammals and away from their predators.

A striped, ginger cat with shining eyes looks at the camera at night.
A feral cat at one of the study sites. Cats have helped cause more than 20 native mammal extinctions.
Northern Territory Government, Author provided

The combination of prescribed burning to protect food and shelter resources, and culling feral livestock, might be all that’s needed to support native mammals and reduce the impact of feral cats.

What about dingoes?

Many scientists have suggested dingoes could also be part of the solution to reducing cat impacts — as cats are believed to avoid dingoes. With this in mind, we explored the relationship between the two predators in this study.

A brownish motion detection camera trap strapped to a tree.
One of more than 1,000 motion detection cameras used in this study.
Jaana Dielenberg, Author provided

We found no evidence dingoes influenced the distribution of feral cats. In fact, survey sites with more dingoes had fewer native small mammals, suggesting a negative impact by dingoes.

But, unlike cats, culling dingoes is not an option because they provide other important ecological roles, and are culturally significant for Indigenous (and non-Indigenous) Australians.

Controlling herbivores, not predators

Our study suggests an effective way to halt and reverse Top End mammal losses is to protect and restore habitat. For example, by improving fire management and controlling feral livestock through culling.




Read more:
EcoCheck: Australia’s vast, majestic northern savannas need more care


It is also very important to conserve the environments that still have high-quality habitat and healthy mammal communities, such as the high-rainfall areas along the northern Australian coast. These areas provide refuge for many of our most vulnerable mammal species.

A photo from a camera trap showing a black-footed tree-rat on its hind legs.
The native black-footed tree-rat has had major declines across northern Australia. It’s vulnerable to cats and is now restricted to areas that still have good quality habitat, fewer herbivores and less frequent fire.
Hugh Davies, Author provided

The tropical savannas of northern Australia are the largest remaining tract of tropical savanna on Earth and new species are still being discovered.

While there’s more research to be done, it’s crucial we start managing habitat better, before we lose more of our precious mammal species.


The authors would like to gratefully acknowledge the support from many Indigenous ranger groups, land managers and Traditional Owners. This includes the Warddeken, Bawinanga, Wardaman and Tiwi rangers, the Traditional Owners and land managers of Kakadu, Garig Gunak Barlu, Judbarra/Gregory, Litchfield and Nitmiluk National Parks, Djelk, Warddeken and Wardaman Indigenous Protected Areas, and Fish River Station and was facilitated by the Northern, Tiwi and Anindilyakwa Land Councils.The Conversation

Alyson Stobo-Wilson, Postdoctoral Research Associate, Charles Darwin University; Brett Murphy, Associate Professor / ARC Future Fellow, Charles Darwin University; Graeme Gillespie, Honorary Research Fellow, University of Melbourne; Jaana Dielenberg, Science Communication Manager, The University of Queensland, and John Woinarski, Professor (conservation biology), Charles Darwin University

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

Climate explained: are we doomed if we don’t manage to curb emissions by 2030?



Thongden Studio/Shutterstock

Robert McLachlan, Massey University


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


Is humanity doomed? If in 2030 we have not reduced emissions in a way that means we stay under say 2℃ (I’ve frankly given up on 1.5℃), are we doomed then?

Humanity is not doomed, not now or even in a worst-case scenario in 2030. But avoiding doom — either the end or widespread collapse of civilisation — is setting a pretty low bar. We can aim much higher than that without shying away from reality.

It’s right to focus on global warming of 1.5℃ and 2℃ in the first instance. The many manifestations of climate change — including heat waves, droughts, water stress, more intense storms, wildfires, mass extinction and warming oceans — all get progressively worse as the temperature rises.

Climate scientist Michael Mann uses the metaphor of walking into an increasingly dense minefield.

Good reasons not to give up just yet

The Intergovernmental Panel on Climate Change described the effects of a 1.5℃ increase in average temperatures in a special report last year. They are also nicely summarised in an article about why global temperatures matter, produced by NASA.

The global average temperature is currently about 1.2℃ higher than what it was at the time of the Industrial Revolution, some 250 years ago. We are already witnessing localised impacts, including the widespread coral bleaching on Australia’s Great Barrier Reef.

This graph shows different emission pathways and when the world is expected to reach global average temperatures of 1.5℃ or 2℃ above pre-industrial levels.
Global Carbon Project, Author provided

Limiting warming to 1.5℃ requires cutting global emissions by 7.6% each year this decade. This does sound difficult, but there are reasons for optimism.




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First, it’s possible technically and economically. For example, the use of wind and solar power has grown exponentially in the past decade, and their prices have plummeted to the point where they are now among the cheapest sources of electricity. Some areas, including energy storage and industrial processes such as steel and cement manufacture, still need further research and a drop in price (or higher carbon prices).

Second, it’s possible politically. Partly in response to the Paris Agreement, a growing number of countries have adopted stronger targets. Twenty countries and regions (including New Zealand and the European Union) are now targeting net zero emissions by 2050 or earlier.

A recent example of striking progress comes from Ireland – a country with a similar emissions profile to New Zealand. The incoming coalition’s “programme for government” includes emission cuts of 7% per year and a reduction by half by 2030.




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Third, it’s possible socially. Since 2019, we have seen the massive growth of the School Strike 4 Climate movement and an increase in fossil fuel divestment. Several media organisations, including The Conversation, have made a commitment to evidence-based coverage of climate change and calls for a Green New Deal are coming from a range of political parties, especially in the US and Europe.

There is also a growing understanding that to ensure a safe future we need to consume less overall. If these trends continue, then I believe we can still stay below 1.5℃.

The pessimist perspective

Now suppose we don’t manage that. It’s 2030 and emissions have only fallen a little bit. We’re staring at 2℃ in the second half of the century.

At 2℃ of warming, we could expect to lose more than 90% of our coral reefs. Insects and plants would be at higher risk of extinction, and the number of dangerously hot days would increase rapidly.




Read more:
Not convinced on the need for urgent climate action? Here’s what happens to our planet between 1.5°C and 2°C of global warming


The challenges would be exacerbated and we would have new issues to consider. First, under the “shifting baseline” phenomenon — essentially a failure to notice slow change and to value what is already lost — people might discount the damage already done. Continuously worsening conditions might become the new normal.

Second, climate impacts such as mass migration could lead to a rise of nationalism and make international cooperation harder. And third, we could begin to pass unpredictable “tipping points” in the Earth system. For example, warming of more than 2°C could set off widespread melting in Antarctica, which in turn would contribute to sea level rise.




Read more:
If warming exceeds 2°C, Antarctica’s melting ice sheets could raise seas 20 metres in coming centuries


But true doom-mongers tend to assume a worst-case scenario on virtually every area of uncertainty. It is important to remember that such scenarios are not very likely.

While bad, this 2030 scenario doesn’t add up to doom — and it certainly doesn’t change the need to move away from fossil fuels to low-carbon options.The Conversation

Robert McLachlan, Professor in Applied Mathematics, Massey University

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

Humans see just 4.7km into the distance. So how can we truly understand what the bushfires destroyed?



Jamie Pittock

Nanda Jarosz, University of Sydney

When the ashes from Australia’s last bushfire season cooled, we were left with a few mind-boggling numbers: 34 human lives lost, more than a billion animals dead, and 18.6 million hectares of land burned.

But those figures don’t necessarily help us understand what was lost. The human mind struggles to grasp very large scales. And in Australia, our colonial past skews the way we view landscapes today.

This disconnect is important. Many scientific concepts, including climate change, happen at scales outside human perception.

Understanding the scale of destruction wrought by bushfires is vital if governments and societies are to adapt in the future. So how can Australians truly come to terms with the damage wrought by last summer’s bushfires?

Dead koala in burnt forest
More than a billion animals died in last summer’s fires.
Daniel Mariuz/AAP

Beyond human perception

On average, humans can only see about 4.7 kilometres into the distance. So perceiving the true extent of the destruction bushfires requires using our imaginations.

This is not only true of bushfires. It also applies to human understanding of climate change, nanoseconds, the size of the Universe and the geological time scale (the millions of years over which continents, oceans and mountains formed).

But science has shown humans have trouble understanding, or imagining, large orders of magnitude. In one US study for example, university students struggled to understand the relative relationships between the age of the Earth, the time required for the origin of the first life forms, and the evolution of dinosaurs and humans.




Read more:
Click through the tragic stories of 119 species still struggling after Black Summer in this interactive (and how to help)


Even university students studying STEM subjects (science, technology, engineering and mathematics) have been shown to struggle with identifying and comparing magnitudes at large scales.

So what’s actually going on in our brains here? Research suggests humans use both numerical and “categorical” information – concepts drawn from their prior experience – to estimate the size of an object. For example, a person estimating the width of a truck might set it as a proportion of the presumed width of highway lanes.

The use of this prior experience can improve the accuracy of estimations. But it can also introduce bias and lead to inexact estimations.

Students in lab
Even university students studying STEM subjects struggled to comprehend large orders of magnitude.
Shutterstock

Understanding vast landscapes

During the fires, satellite images and interactive maps sought to help us understand the scale of the crisis. But they can’t give a full picture of the life destroyed. So how might we otherwise understand the richness lost in a burnt landscape?

Unfortunately, our colonial views of the land are not much help here. British colonisation of Australia, and subsequent land laws, were established on the basis of “terra nullius” – meaning the land belonged to no one. This denied Indigenous people’s prior occupation of the land in order to legitimise its “lawful” settlement by Europeans.

Settlers tended to describe the Australian landscape as empty and unpopulated when, in fact, it was biologically [abundant] and peopled by Indigenous Australians.




Read more:
Friday essay: this grandmother tree connects me to Country. I cried when I saw her burned


These colonial views have had lasting effects. It took more than 200 years before the terra nullius myth was formally dispelled by the 1992 Mabo decision.

Seeking to understand Indigenous perspectives of Country might help non-Indigenous Australians to truly comprehend the loss brought by bushfires. As Indigenous academic Bhiamie Williamson wrote on The Conversation in January:

the experience of Aboriginal peoples in the fire crisis engulfing much of Australia is vastly different to non-Indigenous peoples. How do you support people forever attached to a landscape after an inferno tears through their homelands: decimating native food sources, burning through ancient scarred trees and destroying ancestral and totemic plants and animals?

A human-centric view

Beyond the colonial influence, our generally human-centred view of the world also tends to render invisible the plants and wildlife within it. As Australian researcher Brendan Wintle and others noted in a recent paper, firefighting strategies routinely overlook the need to protect natural assets. They wrote:

It may be unrealistic to expect critical habitats of our most precarious species to compete for firefighting resources with houses and farms. We are far too self-interested. However, could we imagine the last remaining habitat for a brush-tailed rock-wallaby (Petrogale penicillata) might feature as an asset for protection in a fire that is burning through a wilderness area? Surely that needs doing.

In other words, gaining a better understanding the scale of a fire’s destruction means taking a more holistic view of what dwells in the landscape, and might need saving.

Brush-tailed rock wallaby and joey
Rock wallaby habitat should be protected from fire.
Taronga Zoo

Future fires

Under climate change, bushfires in Australia will become more severe and frequent. So bearing in mind our limited abilities to perceive the potential scale of loss next time, what can we do to prepare?

As Wintle argues, more work is needed to organise conservation efforts before, during, and immediately after a bushfire. That includes establishing “insurance populations” of species and keeping them out of harm’s way, and better monitoring and surveying before a fire, so we know which places need protecting.

Williamson wrote of how most Indigenous Australians “have been consigned to the margins in managing our homelands”, watching on as they were “mismanaged and neglected”, which increased the bushfire risk.




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Double trouble: this plucky little fish survived Black Summer, but there’s worse to come


The current bushfire royal commission has pledged to consider ways Indigenous land and fire management practices could improve our resilience to natural disasters. There is much room for ancient traditions to be incorporated into mainstream fire management.

It will take some time to grasp the repercussions of the last bushfire season. But it’s clear that we must transcend colonial, non-Indigenous, human-centred perceptions of the land if we’re to truly understand what was lost.

The Conversation

Nanda Jarosz, PhD Candidate, University of Sydney

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

Carbon emissions are chilling the atmosphere 90km above Antarctica, at the edge of space



Ashleigh Wilson

John French, University of Tasmania; Andrew Klekociuk, University of Tasmania, and Frank Mulligan, National University of Ireland Maynooth

While greenhouse gases are warming Earth’s surface, they’re also causing rapid cooling far above us, at the edge of space. In fact, the upper atmosphere about 90km above Antarctica is cooling at a rate ten times faster than the average warming at the planet’s surface.

Our new research has precisely measured this cooling rate, and revealed an important discovery: a new four-year temperature cycle in the polar atmosphere. The results, based on 24 years of continuous measurements by Australian scientists in Antarctica, were published in two papers this month.

The findings show Earth’s upper atmosphere, in a region called the “mesosphere”, is extremely sensitive to rising greenhouse gas concentrations. This provides a new opportunity to monitor how well government interventions to reduce emissions are working.

Our project also monitors the spectacular natural phenomenon known as “noctilucent” or “night shining” clouds. While beautiful, the more frequent occurrence of these clouds is considered a bad sign for climate change.

Studying the ‘airglow’

Since the 1990s, scientists at Australia’s Davis research station have taken more than 600,000 measurements of the temperatures in the upper atmosphere above Antarctica. We’ve done this using sensitive optical instruments called spectrometers.

These instruments analyse the infrared glow radiating from so-called hydroxyl molecules, which exist in a thin layer about 87km above Earth’s surface. This “airglow” allows us to measure the temperature in this part of the atmosphere.

Scientific equipment
Spectrometer in the optical laboratory at Davis station, Antarctica.
John French

Our results show that in the high atmosphere above Antarctica, carbon dioxide and other greenhouse gases do not have the warming effect they do in the lower atmosphere (by colliding with other molecules). Instead the excess energy is radiated to space, causing a cooling effect.

Our new research more accurately determines this cooling rate. Over 24 years, the upper atmosphere temperature has cooled by about 3℃, or 1.2℃ per decade. That is about ten times greater than the average warming in the lower atmosphere – about 1.3℃ over the past century.

Untangling natural signals

Rising greenhouse gas emissions are contributing to the temperature changes we recorded, but a number of other influences are also at play. These include the seasonal cycle (warmer in winter, colder in summer) and the Sun’s 11-year activity cycle (which involves quieter and more intense solar periods) in the mesosphere.

One challenge of the research was untangling all these merged “signals” to work out the extent to which each was driving the changes we observed.

Surprisingly in this process, we discovered a new natural cycle not previously identified in the polar upper atmosphere. This four-year cycle which we called the Quasi-Quadrennial Oscillation (QQO), saw temperatures vary by 3-4℃ in the upper atmosphere.

Discovering this cycle was like stumbling across a gold nugget in a well-worked claim. More work is needed to determine its origin and full importance.

But the finding has big implications for climate modelling. The physics that drive this cycle are unlikely to be included in global models currently used to predict climate change. But a variation of 3-4℃ every four years is a large signal to ignore.

We don’t yet know what’s driving the oscillation. But whatever the answer, it also seems to affect the winds, sea surface temperatures, atmospheric pressure and sea ice concentrations around Antarctica.

‘Night shining’ clouds

Our research also monitors how cooling temperatures are affecting the occurrence of noctilucent or “night shining” clouds.

Noctilucent clouds are very rare – from Australian Antarctic stations we’ve recorded about ten observations since 1998. They occur at an altitude of about 80km in the polar regions during summer. You can only see them from the ground when the sun is below the horizon during twilight, but still shining on the high atmosphere.




Read more:
Humans are encroaching on Antarctica’s last wild places, threatening its fragile biodiversity


The clouds appear as thin, pale blue, wavy filaments. They are comprised of ice crystals and require temperatures around minus 130℃ to form. While impressive, noctilucent clouds are considered a “canary in the coalmine” of climate change. Further cooling of the upper atmosphere as a result of greenhouse gas emissions will likely lead to more frequent noctilucent clouds.

There is already some evidence the clouds are becoming brighter and more widespread in the Northern Hemisphere.

Sea ice in Antarctica
The new temperature cycle is reflected in the concentration of sea ice in Antacrtica.
John French

Measuring change

Human-induced climate change threatens to alter radically the conditions for life on our planet. Over the next several decades – less than one lifetime – the average global air temperature is expected to increase, bringing with it sea level rise, weather extremes and changes to ecosystems across the world.

Long term monitoring is important to measure change and test and calibrate ever more complex climate models. Our results contribute to a global network of observations coordinated by the Network for Detection of Mesospheric Change for this purpose.

The accuracy of these models is critical to determining whether government and other interventions to curb climate change are indeed effective.




Read more:
Anatomy of a heatwave: how Antarctica recorded a 20.75°C day last month


The Conversation


John French, Atmospheric physicist, University of Tasmania; Andrew Klekociuk, Principal Research Scientist, Australian Antarctic Division and Adjunct Senior Lecturer, University of Tasmania, and Frank Mulligan, , National University of Ireland Maynooth

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

‘A wake-up call’: why this student is suing the government over the financial risks of climate change



Shutterstock

Jacqueline Peel, University of Melbourne and Rebekkah Markey-Towler, University of Melbourne

As the world warms, the value of “safe” investments might be at risk from inadequate climate change policies. This prospect is raised by a world-first climate change case, filed in the federal court last week.

Katta O’Donnell – a 23-year-old law student from Melbourne – is suing the Australian government for failing to disclose climate change risks to investors in Australia’s sovereign bonds.




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Sovereign bonds involve loans of money from investors to governments for a set period at a fixed interest rate. They’re usually thought to be the safest form of investment. For example, many Australians are invested in sovereign bonds through their superannuation funds.

But as climate change presents major risks to our economy as well as the environment, O’Donnell’s claim is a wake-up call to the government that it can no longer bury its head in the sand when it comes to this vulnerability.

Katta O'Donnell smiles at the camera in a long-sleeved black top.
Katta O’Donnell is bringing the class action lawsuit against the Australian government.
Molly Townsend

O’Donnell’s arguments

O’Donnell argues Australia’s poor climate policies – ranked among the lowest in the industrialised world – put the economy at risk from climate change. She says climate-related risks should be properly disclosed in information documents to sovereign bond investors.

O’Donnell’s claim alleges that by failing to disclose this information, the federal government breaches its legal duty. It alleges the government has engaged in misleading and deceptive conduct, and government officials breached their duty of care and diligence.

This is a standard similar to that owed by Australian company directors. Analysis from leading barristers indicates that directors who fail to consider climate risks could be found liable for breaching their duty of care and diligence.

O’Donnell argues government officials providing information to investors in sovereign bonds should meet the same benchmark.

Climate change as a financial risk

Under climate change, the world is already experiencing physical impacts, such as intense droughts and unprecedented bushfires. But we’re also experiencing “transition impacts” from steps countries take to prevent further warming, such as transitioning away from coal.

Combined, these impacts of climate change create financial risks. For example, by damaging property, assets and operations, or by reducing demand for fossil fuels with the risk coal mines and reserves become stranded assets.

This thinking is becoming mainstream among Australian economists. As the Australian Prudential Regulation Authority’s Geoff Summerhayes put it:

When a central bank, a prudential regulator and a conduct regulator, with barely a hipster beard or hemp shirt between them, start warning that climate change is a financial risk, it’s clear that position is now orthodox economic thinking.

Why safe investments are under threat

Sovereign bonds are a long-term investment. Katta O’Donnell’s bonds, for example, will mature in 2050. These time-frames dovetail with scientific projections about when the world will see severe impacts and costs from climate change.

And climate change is likely to hit Australia particularly hard. We’ve seen the beginning of this in the summer’s ferocious bushfires, which cost the economy more than A$100 billion.




Read more:
With costs approaching $100 billion, the fires are Australia’s costliest natural disaster


Over time, climate risks may impact sovereign bonds and affect Australia’s financial position in a number of ways. For example, by impacting GDP when the productive capacity of the economy is reduced by severe fires or floods.

Frequent climate-related disasters could also hit foreign exchange rates, causing fluctuations of the Australian dollar, as well as putting Australia’s AAA credit rating at risk. These risks would reduce if the government took climate change more seriously.

Already, some investors are voting with their feet. Last November, Sweden’s central bank announced it had sold Western Australian and Queensland bonds, stating Australia is “not known for good climate work”.

Unprecedented, but not novel

O’Donnell’s case against the federal government is an unprecedented climate case, even if its arguments are not novel.

Australia has been a “hotspot” for climate litigation in recent years, but the O’Donnell case is the first to sue the Australian government in an Australian court.

Previous cases suing governments have often raised human rights, such as the high-profile Urgenda case in 2015 against the Dutch government – the first case in the world establishing governments owe their citizens a legal duty to prevent climate change.

The O’Donnell case is also unique in its focus on sovereign bonds. But cases alleging misleading climate-related disclosures are themselves not new.

In Australia, shareholders sued the Commonwealth Bank of Australia in 2017 for failing to disclose climate change-related risks in its 2016 annual report. The case was settled after the bank agreed to improve disclosures in subsequent reports.




Read more:
Climate change is a financial risk, according to a lawsuit against the CBA


In another headline-making case, 23-year-old council worker Mark McVeigh is taking his superannuation fund, Retail Employees Superannuation Trust, to court seeking similar disclosures.

The O’Donnell case builds on this line of precedent, extending it to disclosures in bond information documents. As such, courts will likely take it seriously.

What precedent might it set?

If the O’Donnell case is successful it could establish the need for disclosure of climate-related financial risks for a range of investments.

At a minimum, a ruling in O’Donnell’s favour may compel the Australian government to disclose climate-related risks in its information documents for investors. This might make people think twice about how they choose to invest their money, especially as investors seek to “green” their portfolios.

It could also give rise to litigation using the same legal theory in sovereign bond disclosure claims against other governments, much in the way that the Urgenda case has spawned copycat proceedings from Belgium to Canada.

Whether the case provides the impetus for further government action to improve the effectiveness of Australia’s climate policies remains to be seen.

Still, it’s clear climate-related financial risks have entered the corporate boardroom. With this case, they’ve now come knocking at the government’s door.The Conversation

Jacqueline Peel, Professor of Environmental and Climate Law, University of Melbourne and Rebekkah Markey-Towler, Research assistant, University of Melbourne

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

How a scientific spat over how to name species turned into a big plus for nature



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Stephen Garnett, Charles Darwin University; Les Christidis, Southern Cross University; Richard L. Pyle, University of Hawaii, and Scott Thomson, Universidade de São Paulo

Taxonomy, or the naming of species, is the foundation of modern biology. It might sound like a fairly straightforward exercise, but in fact it’s complicated and often controversial.

Why? Because there’s no one agreed list of all the world’s species. Competing lists exist for organisms such as mammals and birds, while other less well-known groups have none. And there are more than 30 definitions of what constitutes a species. This can make life difficult for biodiversity researchers and those working in areas such as conservation, biosecurity and regulation of the wildlife trade.

In the past few years, a public debate erupted among global taxonomists, including those who authored and contributed to this article, about whether the rules of taxonomy should be changed. Strongly worded ripostes were exchanged. A comparison to Stalin was floated.

But eventually, we all came together to resolve the dispute amicably. In a paper published this month, we proposed a new set of principles to guide what one day, we hope, will be a single authoritative list of the world’s species. This would help manage and conserve them for future generations.

In the process, we’ve shown how a scientific stoush can be overcome when those involved try to find common ground.

Baby crocodile emerging from egg.
Scientists worked out a few differences over how to name species.
Laurent Gillieron/EPA

How it all began

In May 2017 two of the authors, Stephen Garnett and Les Christidis, published an article in Nature. They argued taxonomy needed rules around what should be called a species, because currently there are none. They wrote:

for a discipline aiming to impose order on the natural world, taxonomy (the classification of complex organisms) is remarkably anarchic […] There is reasonable agreement among taxonomists that a species should represent a distinct evolutionary lineage. But there is none about how a lineage should be defined.

‘Species’ are often created or dismissed arbitrarily, according to the individual taxonomist’s adherence to one of at least 30 definitions. Crucially, there is no global oversight of taxonomic decisions — researchers can ‘split or lump’ species with no consideration of the consequences.

Garnett and Christidis proposed that any changes to the taxonomy of complex organisms be overseen by the highest body in the global governance of biology, the International Union of Biological Sciences (IUBS), which would “restrict […] freedom of taxonomic action.”




Read more:
Taxonomy, the science of naming things, is under threat


An animated response

Garnett and Christidis’ article raised hackles in some corners of the taxonomy world – including coauthors of this article.

These critics rejected the description of taxonomy as “anarchic”. In fact, they argued there are detailed rules around the naming of species administered by groups such as the International Commission on Zoological Nomenclature and the International Code of Nomenclature for algae, fungi, and plants. For 125 years, the codes have been almost universally adopted by scientists.

So in March 2018, 183 researchers – led by Scott Thomson and Richard Pyle – wrote an animated response to the Nature article, published in PLoS Biology.

They wrote that Garnett and Christidis’ IUBS proposal was “flawed in terms of scientific integrity […] but is also untenable in practice”. They argued:

Through taxonomic research, our understanding of biodiversity and classifications of living organisms will continue to progress. Any system that restricts such progress runs counter to basic scientific principles, which rely on peer review and subsequent acceptance or rejection by the community, rather than third-party regulation.

In a separate paper, another group of taxonomists accused Garnett and Christidis of trying to suppress freedom of scientific thought, likening them to Stalin’s science advisor Trofim Lysenko.

Sea sponge under a microscope
Taxonomy can influence how conservation funding is allocated.
Queensland Museum

Finding common ground

This might have been the end of it. But the editor at PLoS Biology, Roli Roberts, wanted to turn consternation into constructive debate, and invited a response from Garnett and Christidis. In the to and fro of articles, we all found common ground.

We recognised the powerful need for a global list of species – representing a consensus view of the world’s taxonomists at a particular time.




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Such lists do exist. The Catalogue of Life, for example, has done a remarkable job in assembling lists of almost all the world’s species. But there are no rules on how to choose between competing lists of validly named species. What was needed, we agreed, was principles governing what can be included on lists.

As it stands now, anyone can name a species, or decide which to recognise as valid and which not. This creates chaos. It means international agreements on biodiversity conservation, such as the Convention on International Trade in Endangered Species (CITES) and the Convention on the Conservation of Migratory Species of Wild Animals (CMS), take different taxonomic approaches to species they aim to protect.

We decided to work together. With funding from the IUBS, we held a workshop in February this year at Charles Darwin University to determine principles for devising a single, agreed global list of species.

Pengiuns embracing each other.
The sparring scientists came together to develop agreed principles.
Shutterstock

Participants came from around the world. They included taxonomists, science governance experts, science philosophers, administrators of the nomenclatural (naming) codes, and taxonomic users such as the creators of national species lists.

The result is a draft set of ten principles that to us, represent the ideals of global science governance. They include that:

  • the species list be based on science and free from “non-taxonomic” interference
  • all decisions about composition of the list be transparent
  • governance of the list aim for community support and use
  • the listing process encompasses global diversity while accommodating local knowledge.

The principles will now be discussed at international workshops of taxonomists and the users of taxonomy. We’ve also formed a working group to discuss how a global list might come together and the type of institution needed to look after it.

We hope by 2030, a scientific debate that began with claims of anarchy might lead to a clear governance system – and finally, the world’s first endorsed global list of species.


The following people provided editorial comment for this article: Aaron M Lien, Frank Zachos, John Buckeridge, Kevin Thiele, Svetlana Nikolaeva, Zhi-Qiang Zhang, Donald Hobern, Olaf Banki, Peter Paul van Dijk, Saroj Kanta Barik and Stijn Conix.

The Conversation

Stephen Garnett, Professor of Conservation and Sustainable Livelihoods, Charles Darwin University; Les Christidis, Professor, Southern Cross University; Richard L. Pyle, Associate lecturer, University of Hawaii, and Scott Thomson, Research associate, Universidade de São Paulo

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