Climate explained: why is the Arctic warming faster than other parts of the world?


Shutterstock/Michal Balada

Steve Turton, CQUniversity Australia


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


What is Arctic amplification? Do we know what is causing this phenomenon? What effects is it having, both in the region and for the world? Is Antarctica experiencing the same thing?

Human civilisation and agriculture first emerged about 12,000 years ago in the early Holocene. Our ancestors benefited from a remarkably stable climate during this time as carbon dioxide levels in the atmosphere remained near 280ppm until the beginning of the industrial revolution in the 1800s.

Prior to the 1800s, the balance between incoming and outgoing energy (radiation) at the top of the atmosphere (the greenhouse effect) maintained global average temperatures for many centuries. Only small changes in solar output and occasional volcanic eruptions caused periods of relative warming and cooling. For example, the Little Ice Age was a cooler period between 1300 and 1870.

Today carbon dioxide levels are near 420ppm and all greenhouse gases are rising rapidly due to the burning of fossil fuels, industrial processes, tropical forest destruction, landfills and agriculture. The global average temperature has increased by a little more than 1℃ since 1900.

This figure seems small, but the Arctic region has warmed by about 2℃ in this time — twice as fast.

This warming differential between the poles and the tropics is known as Arctic (or polar) amplification.

A map showing which parts of the world are warming faster than others.
The Arctic region is warming faster than other parts of the globe.
Berkeley Earth, CC BY-ND

It occurs whenever there is any change in the net radiation balance of Earth, and this produces a larger change in temperature near the poles than the global average. It is typically measured as the ratio of polar warming to tropical warming.

Melting ice

So how is climate change and associated global heating driving Arctic amplification? This amplification is primarily caused by melting ice — a process that is increasing in the Arctic at a rate of 13% per decade.

Ice is more reflective and less absorbent of sunlight than land or the surface of an ocean. When ice melts, it typically reveals darker areas of land or sea, and this results in increased sunlight absorption and associated warming.

Polar amplification is much stronger in the Arctic than in Antarctica. This difference is because the Arctic is an ocean covered by sea ice, while Antarctica is an elevated continent covered in more permanent ice and snow.

In fact, the Antarctic continent has not warmed in the past seven decades, despite a steady increase in the atmospheric concentrations of greenhouse gases.

The exception is the Antarctic peninsula, which juts out further north into the Southern Ocean and has been warming faster than any other terrestrial environment in the southern hemisphere during the latter half of the 20th century.




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


Satellite data also show that between 2002 and 2020, Antarctica lost an average of 149 billion metric tonnes of ice per year, partly because the oceans around the continent are warming.

Effects of Arctic warming

One of the most significant effects of Arctic amplification is the weakening of west-to-east jet streams in the northern hemisphere. As the Arctic warms at a faster rate than the tropics, this results in a weaker atmospheric pressure gradient and hence lower wind speeds.

The links between Arctic amplification, slowing (or meandering) jet streams, blocking highs and extreme weather events in the mid to high latitudes of the northern hemisphere is controversial. One view is that the link is strong and the major driver behind recent severe summer heat waves and winter cold waves. But more recent research questions the validity of these links for the mid latitudes.

Here we look at the larger body of evidence that supports the relationship between Arctic warming and slowing jet streams.




Read more:
Siberia heatwave: why the Arctic is warming so much faster than the rest of the world


The Arctic is warming much faster than the rest of the planet and the loss of reflective ice contributes somewhere between 30-50% of Earth’s global heating. This rapid loss of ice affects the polar jet stream, a concentrated pathway of air in the upper atmosphere which drives the weather patterns across the northern hemisphere.

The weakened jet stream meanders and brings the polar vortex further south, which results in extreme weather events in North America, Europe and Asia.

Graphic explaing the polar vortex

NOAA, CC BY-ND

So what are the future prospects for Australia and Aotearoa/New Zealand? Global climate models project stronger surface warming in the Arctic than the Antarctic under climate change. Given that temperatures above the Antarctic continent have remained stable for over 70 years despite the rise in greenhouse gases, we might expect little change for our region — just normal climatic variability due to other climate drivers like the El Niño-Southern Oscillation, the Southern Annular Mode, and the Indian Ocean Dipole.

But as the tropics continue to warm and expand, we may expect an increase in the pressure gradient between the tropics and Antarctica that will lead to increased circumpolar westerlies winds.

The recent intensification and more poleward location of the southern hemisphere belt of westerly winds have been linked to continental droughts and wildfires, including those in Australia. We can also expect strengthening westerlies to affect mixing in the Southern Ocean, which could reduce its capacity to take up carbon dioxide and enhance the ocean-driven melting of ice shelves fringing the West Antarctic Ice Sheet.

These changes in turn have far-reaching implications for global ocean circulation and sea level rise.The Conversation

Steve Turton, Adjunct Professor of Environmental Geography, CQUniversity Australia

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

Hundreds of Australian lizard species are barely known to science. Many may face extinction


E Vanderduys, Fourni par l’auteur

Jane Melville, Museums Victoria and Reid Tingley, Monash UniversityMost of the incredible diversity of life on Earth is yet to be discovered and documented. In some groups of organisms – terrestrial arthropods such as spiders and scorpions, marine invertebrates such as sponges and molluscs, and others – scientists have described fewer than 20% of species.

Even our knowledge of more familiar creatures such as fish and reptiles is far from complete. In our new research, we studied 1,034 known species of Australian lizards and snakes and found we know so little about 164 of them that not even the experts know whether they are fully described or not. Of the remaining 870, almost a third probably need some work to be described properly.

Map of Australia shaded in colours from blue to red.
Return on investment for taxonomic research on lizards and snakes in Australia. Red areas have high numbers of species and high conservation value. Hotspots include the Kimberley in WA, northern tropical savannas and also far north eastern QLD.
R. Tingley, Author provided

Documenting and naming what species are out there – the work of taxonomists – is crucial for conservation, but it can be difficult for researchers to decide where to focus their efforts. Alongside our lizard research, we have developed a new “return on investment” approach to identify priority species for our efforts.

We identified several hotspots across Australia where research is likely to be rewarded. More broadly, our approach can help target taxonomic research for conservation worldwide.

Why we need to look at species more closely

As more and more species are threatened by land clearing, climate change and other human activities, our research highlights that we are losing even more biodiversity than we know.

Conservation often relies on species-level assessments such as those conducted by the International Union for Conservation of Nature (IUCN) Red List, which lists threatened species. Although new species are being discovered all the time, a key problem is that already named “species” may harbour multiple undocumented and unnamed species. This hidden diversity remains invisible to conservation assessment.

The Roma Earless Dragon (Tympanocryptis wilsoni), described in 2014, lives only in grasslands in the western Darling Downs QLD and has recently been listed as Vulnerable in Queensland.
A. O’Grady, Author provided

One such example are the Grassland Earless Dragons (Tympanocryptis spp.) found in the temperate native grasslands of south-eastern Australia. These small secretive lizards were grouped within a single species (Tympanocryptis pinguicolla) and listed as Endangered on the IUCN Red List.

But recent taxonomic research split this single species into four, each occurring in an isolated region of grasslands. One of these new species may represent the first extinction of a reptile on mainland Australia and the other three have a high probability of being threatened.




Read more:
Why we’re not giving up the search for mainland Australia’s ‘first extinct lizard’


Scientists call documenting and describing species “taxonomy”. Our research shows the importance of prioritising taxonomy in the effort to conserve and protect species.

Taxonomists at work

Many government agencies do take some account of groups smaller than species in their conservation efforts, such as distinct populations. But these are often ambiguously defined and lack formal recognition, so they are not widely used. That’s where taxonomists come in, to identify species and describe them fully.

Our new research was a collaboration of 30 taxonomists and systematists, who teamed up to find a good way of working out which species should be a priority for taxonomic research for conservation outcomes. This new approach compares the amount of work needed with the likelihood of finding previously unknown species that are at risk of extinction.

Barrier Range Dragon (Ctenophorus mirrityana), described in 2013, is restricted to rocky ranges in western NSW and is listed as Endangered in NSW.
S. Wilson, Author provided

The research team, who are experts on the taxonomy and systematics of Australia’s reptiles, implemented this new approach on Australian lizards and snakes. This group of reptiles is ideal as a test case because Australia is a global hotspot of lizard diversity – and we also have a strong community of taxonomic experts.

Australia’s lizards and snakes

Of the 1,034 Australian lizard and snake species, we were able to assess whether 870 of them may contain undescribed species. This means we know so little about the remaining 164 species that even the experts could not make an informed opinion on whether they contain hidden diversity. There is so much still to learn!

Of the 870 species experts could assess, they determined 282 probably or definitely needed more taxonomic research. Mapping the distributions of these species indicated hotspot regions for this taxonomic research, including the Kimberley, the Tanami Desert region, western Victoria and offshore islands (such as Tasmania, Lord Howe and Norfolk Islands). Some areas in the Kimberley region had more than 60 species that need further taxonomic research.

In this map, red hotspot areas have lower species diversity but still a very high average return on investment. National hotspots include Tasmania, western Victoria and the Tanami Desert region in WA and NT.
R. Tingley, Author provided

We found 17.6% of the 282 species that need more taxonomic research contained undescribed species that would probably be of conservation concern, and 24 had a high probability of being threatened with extinction. Taxonomists know that there are undescribed species because there is some data available already but the description of these species – the process of defining and naming – has not been done.

These high-priority species belong to a range of families including geckos, skinks and dragons found across Australia.

The high number of undescribed species, especially those with significant likelihood of being endangered, was a shock to even the experts. The IUCN currently estimates only 6.3% of Australian lizards and snakes require taxonomic revision, but this is obviously a significant underestimate.

A race against extinction

Beyond lizards, there is a huge backlog of species awaiting description.

Recent projects have used genetic analyses to discover unknown species, including a $180 million global BIOSCAN effort aiming to identify millions of new species. However, genetics is only a first step in the formal recognition of species.




Read more:
About 500,000 Australian species are undiscovered – and scientists are on a 25-year mission to finish the job


The taxonomic process of documenting, describing and naming species requires multiple further steps. These steps include a comprehensive diagnostic assessment using a combination of evidence, such as genetics and morphology, to uniquely distinguish each species from another. This process requires a high level of familiarity and scholarship of the group in question.

The Mt Elliot Sunskink (Lampropholis elliotensis), described in 2018, is found in leaf litter of highland rainforest above 600m on Mt Elliot in Bowling Green Bay National Park. Queensland, and is probably Vulnerable.
C. Hoskin, Author provided

Among the Australian lizards and snakes alone, there is a backlog of 59 undescribed species for which only the final elements of taxonomic research are awaiting completion.

To work through these taxonomic backlogs – let alone species that are so far entirely unknown – resources need to be invested in taxonomy, including research funding and increased provision of viable career paths.

Without taxonomic research, the conservation assessment of these undocumented species will not proceed. There are untold numbers of species needing taxonomic research that are already under threat of extinction. If we don’t hurry, they may go extinct before we even know they exist.The Conversation

Jane Melville, Senior Curator, Terrestrial Vertebrates, Museums Victoria and Reid Tingley, Lecturer, Monash University

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

About 500,000 Australian species are undiscovered – and scientists are on a 25-year mission to finish the job


Wikimedia

Kevin Thiele, The University of Western Australia and Jane Melville, Museums VictoriaHere are two quiz questions for you. How many species of animals, plants, fungi, fish, insects and other organisms live in Australia? And how many of these have been discovered and named?

To the first, the answer is we don’t really know. But the best guess of taxonomists – the scientists who discover, name, classify and document species – is that Australia’s lands, rivers, coasts and oceans probably house more than 700,000 distinct species.

On the second, taxonomists estimate almost 200,000 species have been scientifically named since Europeans first began exploring, collecting and classifying Australia’s remarkable fauna and flora.

Together, these estimates are disturbing. After more than 300 years of effort, scientists have documented fewer than one-third of Australia’s species. The remaining 70% are unknown, and essentially invisible, to science.

Taxonomists in Australia name an average 1,000 new species each year. At that rate, it will take at least 400 years to complete even a first-pass stocktake of Australia’s biodiversity.

This poor knowledge is a serious threat to Australia’s environment. And a first-of-its kind report released today shows it’s also a huge missed economic opportunity. That’s why today, Australia’s taxonomists are calling on governments, industry and the community to support an important mission: discovering and documenting all Australian species within 25 years.

Australia: a biodiversity hotspot

Biologically, Australia is one of the richest and most diverse nations on Earth – between 7% and 10% of all species on Earth occur here. It also has among the world’s highest rates of species discovery. But our understanding of biodiversity is still very, very incomplete.

Of course, First Nations peoples discovered, named and classified many species within their knowledge systems long before Europeans arrived. But we have no ready way yet to compare their knowledge with Western taxonomy.

Finding new species in Australia is not hard – there are almost certainly unnamed species of insects, spiders, mites and fungi in your backyard. Any time you take a bush holiday you’ll drive past hundreds of undiscovered species. The problem is recognising the species as new and finding the time and resources to deal with them all.

Taxonomists describe and name new species only after very careful due diligence. Every specimen must be compared with all known named species and with close relatives to ensure it is truly a new species. This often involves detailed microscopic studies and gene sequencing.

More fieldwork is often needed to collect specimens and study other species. Specimens in museums and herbaria all over the world sometimes need to be checked. After a great deal of work, new species are described in scientific papers for others to assess and review.

So why do so many species remain undiscovered? One reason is a shortage of taxonomists trained to the level needed. Another is that technologies to substantially speed up the task have only been developed in the past decade or so. And both these, of course, need appropriate levels of funding.

Of course, some groups of organisms are better known than others. In general, noticeable species – mammals, birds, plants, butterflies and the like – are fairly well documented. Most less noticeable groups – many insects, fungi, mites, spiders and marine invertebrates – remain poorly known. But even inconspicuous species are important.

Fungi, for example, are essential for maintaining our natural ecosystems and agriculture. They fertilise soils, control pests, break down litter and recycle nutrients. Without fungi, the world would literally grind to a halt. Yet, more than 90% of Australian fungi are believed to be unknown.




Read more:
How we discovered a hidden world of fungi inside the world’s biggest seed bank


fungi on log
Fungi plays an essential ecosystem role.
Shutterstock

Mind the knowledge gap

So why does all this matter?

First, Australia’s biodiversity is under severe and increasing threat. To manage and conserve our living organisms, we must first discover and name them.

At present, it’s likely many undocumented species are becoming extinct, invisibly, before we know they exist. Or, perhaps worse, they will be discovered and named from dead specimens in our museums long after they have gone extinct in nature.

Second, many undiscovered species are crucial in maintaining a sustainable environment for us all. Others may emerge as pests and threats in future; most species are rarely noticed until something goes wrong. Knowing so little about them is a huge risk.

Third, enormous benefits are to be gained from these invisible species, once they are known and documented. A report released today
by Deloitte Access Economics, commissioned by Taxonomy Australia, estimates a benefit to the national economy of between A$3.7 billion and A$28.9 billion if all remaining Australian species are documented.

Benefits will be greatest in biosecurity, medicine, conservation and agriculture. The report found every $1 invested in discovering all remaining Australian species will bring up to $35 of economic benefits. Such a cost-benefit analysis has never before been conducted in Australia.

The investment would cover, among other things, research infrastructure, an expanded grants program, a national effort to collect specimens of all species and new facilities for gene sequencing.




Read more:
A few months ago, science gave this rare lizard a name – and it may already be headed for extinction


Two scientists walk through wetlands holding boxes
Discovering new species often involves lots of field work.
Shutterstock

Mission possible

Australian taxonomists – in museums, herbaria, universities, at the CSIRO and in
government departments – have spent the last few years planning an ambitious mission to discover and document all remaining Australian species within a generation.

So, is this ambitious goal achievable, or even imaginable? Fortunately, yes.

It will involve deploying new and emerging technologies, including high-throughput robotic DNA sequencing, artificial intelligence and supercomputing. This will vastly speed up the process from collecting specimens to naming new species, while ensuring rigour and care in the science.

A national meeting of Australian taxonomists, including the young early career researchers needed to carry the mission through, was held last year. The meeting confirmed that with the right technologies and more keen and bright minds trained for the task, the rate of species discovery in Australia could be sped up by the necessary 16-fold – reducing 400 years of effort to 25 years.

With the right people, technologies and investment, we could discover all Australian species. By 2050 Australia could be the world’s first biologically mega-rich nation to have documented all our species, for the direct benefit of this and future generations.




Read more:
Hundreds of Australian lizard species are barely known to science. Many may face extinction


The Conversation


Kevin Thiele, Adjunct Assoc. Professor, The University of Western Australia and Jane Melville, Senior Curator, Terrestrial Vertebrates, Museums Victoria

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

Don’t forget the need for zero-emission buses in the push for electric cars


NH53/Flickr, CC BY

John Stone, The University of Melbourne; Iain Lawrie, The University of Melbourne, and Nat Manawadu, The University of MelbourneAs part of efforts to decarbonise urban transport, Australian states and the ACT have announced various zero-emission bus trials and targets for replacing diesel buses. These trials are designed to help resolve some of the complex technical and contractual issues facing bus operators and public transport agencies.

It is important to remember the vital role of buses, and public transport more generally, in decarbonising the transport sector — Australia’s third-largest source of greenhouse gas emissions. We fear this point has been lost in recent climate advocacy highlighting the slow pace of the transition to green propulsion for private cars in Australia.

Chart showing Australian transport sector greenhouse gas emissions from 1990 to 2020

Chart. The Conversation. Data: National Greenhouse Gas Inventory Quarterly Update December 2020, CC BY



Read more:
Transport is letting Australia down in the race to cut emissions


Our research aims to learn more about the obstacles to an effective transition to zero-emission buses. We are engaging mainly with groups connected with the trial announced by the Victorian Department of Transport in late 2020, but the issues are similar across Australia.

Why can’t we rely on electric cars?

Even if Australia’s transition to green-electric cars is successful, the climate benefits will be less than we need. The carbon costs of manufacturing replacements for Australia’s 20 million-strong vehicle fleet will be equivalent to around 20 years’ emissions from Australia’s dirtiest brown coal generator at Yallourn. And tonnes of concrete and bitumen will continue to be laid for new toll roads and car parks.

A city of electric vehicles will also perpetuate the fatal burdens of car dependence: urban sprawl, inequitable access to the riches of city life, suppression of cycling and walking, and a host of health risks ranging from physical inactivity to air pollution. Even if exhausts were cleaner, recent UK research shows a significant proportion of damaging particulates come from worn tyres and brake linings.

To protect the climate and to make city life safer, fairer and healthier, we need policies that take cars off the roads, regardless of how they are fuelled.

Late afternoon congestion in both directions on the Kwinana Freeway (looking north towards and onto the Narrows Bridge) in Perth, Western Australia
Apart from emissions, electric cars won’t solve the other problems associated with heavy car use – such as traffic jams – and could even make them worse.
Orderinchaos/Wikimedia Commons, CC BY-SA



Read more:
Think taxing electric vehicle use is a backward step? Here’s why it’s an important policy advance


Bus services are under-utilised — we can fix that

The technical complexities of the transition to zero-emission buses could, if we are not careful, lead governments to lose sight of this bigger picture. Buses can help reduce demand for car travel, but only if they operate as effective links in a seamless public transport network.

In Melbourne, for example, many buses run almost empty. Routes are convoluted and services infrequent. It would be a travesty to invest millions in moving to greener buses without improving services in ways that increase patronage.

We can use internationally proven techniques to restructure the network so buses provide practical and convenient alternatives to the car. We can then attract a new generation of riders who currently think that “buses are not for me”. This is achievable within current Australian urban densities.




Read more:
Why cities planning to spend billions on light rail should look again at what buses can do


What other challenges must be overcome?

The first technical challenge is to decide between electric battery and hydrogen power. Most governments are leaning towards batteries. This is largely because the technology and its support systems are more evolved.

However, not all battery buses are created equal. One configuration might work well for a bus that will operate on short routes and can easily return to base to recharge. A bus that will operate on longer or steeper routes might need a different set-up. Operators will need to understand these trade-offs before they order new vehicles.

electric bus operating on the Balmain route in Sydney
One of Sydney’s ‘Electric Blu’ buses running on the Balmain route – operators must select battery-powered buses that suit their intended route.
MDRZ/Wikimedia Commons, CC BY-SA

As established supply chains and cost structures for fossil fuels become obsolete, operators will also need to come to grips with the intricacies of Australia’s electricity market. At the same time, the power industry is grappling with new forecasts for demand and the infrastructure required for secure supply. Added to this, there are fears of a repeat of the “gold-plating” by private energy providers and distributors that has plagued the industry in recent years.

The change of power source also creates new challenges for fleet managers. If the transition takes several years, how will an operator manage the changing demands on depot space for refuelling and maintenance? Are depots in the right locations for new patterns of refuelling and deployment? How will the workforce gain the new skills they will need?




Read more:
Climate explained: why switching to electric transport makes sense even if electricity is not fully renewable


Issues won’t be resolved overnight

These issues and other technical questions can certainly be resolved. However, the institutional framework in which this must occur makes it hard to imagine it can be done quickly.

In Melbourne, buses operate under more than 15 different contracts, some with multinationals and others with tiny family businesses. These contracts vary in their provisions for determining routes and frequencies, for fleet and depot ownership, and for rollover or re-tendering. This complexity is a historical legacy compounded by decades of political and bureaucratic inertia.

The challenge for governments is to find a path to introducing zero-emission buses and reforming bus networks that deals with the technical uncertainties and the allocation of cost and risk in a fragmented market. The arrival of new commercial players — offering combined bus procurement, operation, charging infrastructure and energy supply — makes the market all the more complex. Nevertheless, success is crucial for the climate and for the health of our cities.




Read more:
Climate policy that relies on a shift to electric cars risks entrenching existing inequities


The Conversation


John Stone, Senior Lecturer in Transport Planning, The University of Melbourne; Iain Lawrie, PhD Candidate and Sessional Lecturer in Planning, The University of Melbourne, and Nat Manawadu, Research Assistant, Architecture, Building and Planning, The University of Melbourne

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