It’s a savage summer in the Northern Hemisphere – and climate change is slashing the odds of more heatwaves


Andrew King, University of Melbourne and Ben Henley, University of Melbourne

In Australia we know about sweltering summer heat. We all remember the images of burned koala paws, collapsing tennis players and, far more seriously, the tragic events of Black Saturday.

Aussies may scoff at Britain’s idea of a heatwave, but this time it’s the real deal and it’s no laughing matter.

Extreme heat has hit locations throughout the Northern Hemisphere, in places as far apart as Montreal, Glasgow, Tokyo and Lapland. In the past few weeks heat records have tumbled in a wide range of places, most notably:




Read more:
Why hot weather records continue to tumble worldwide


Heat has not been the only problem. Much of northern Europe is experiencing a very persistent drought, with little to no measurable rainfall in months. This has caused the normally lush green fields of England and other European countries to turn brown and even reveal previously hidden archaeological monuments.

There have also been major wildfires in northern England, Sweden and, most recently and devastatingly, Greece. The Greek wildfires came off the back of a very dry winter and spring.

What’s behind the widespread extreme heat?

The jet stream, a high-altitude band of air that pushes weather systems around at lower altitudes, has been weaker than normal. It has also been positioned unusually far to the north, particularly over Europe. This has kept the low-pressure systems that often drive wind and rain over northern Europe at bay.

The jet stream has remained locked in roughly the same position over the Atlantic Ocean and northern Europe for the past couple of months. This has meant that the same weather types have remained over the same locations most of the time.

Weather is typically more transient than it has been recently. Even when we do have blocking high-pressure systems associated with high temperatures in northern Europe, they don’t normally linger as long as this.

Is it driven by climate change?

Although climatologists have made great strides in recent years in the field of event attribution – identifying the human climate fingerprint on particular extreme weather events – it is hard to quantify the role of climate change in an event that is still unfolding.

Until the final numbers are in we won’t be able to tell just how much climate change has altered the likelihood or intensity of these particular heat extremes.

Having said that, we can use past analyses of extreme heat events, together with future climate change projections, to infer whether climate change is playing a role in these events.

We also know that increasing numbers of hot temperature records are being set, and that the increased probability of hot temperature records can indeed be attributed to the human influence on the climate.

In Europe especially, there is already a large body of literature that has looked at the role of human-caused climate change in heat extremes. In fact, the very first event attribution study, led by Peter Stott from the UK Met Office, found that human-caused climate change had at least doubled the likelihood of the infamous European heatwave of 2003.

For all manner of heat extremes in Europe and elsewhere, including in Japan, a clear and discernible link with climate change has been made.

Research has also shown that heat extremes similar to those witnessed over the past month or two are expected to become more common as global temperatures continue to climb. The world has so far had around 1℃ of global warming above pre-industrial levels, but at the global warming limits proposed in the Paris climate agreement, hot summers like that of 2003 in central Europe would be a common occurrence.

At 2℃ of global warming, the higher of the two Paris targets, 2003-like hot summers would very likely happen in most years.

Similarly, we know that heat exposure and heat-induced deaths in Europe will increase with global warming, even if we can limit this warming to the levels agreed in Paris.




Read more:
Yes, the Arctic’s freakishly warm winter is due to humans’ climate influence


But summers have always been hot, haven’t they?

For most parts of the world summers have got warmer, and the hottest summer on record is relatively recent – such as 2003 in parts of central Europe and 2010 in much of eastern Europe. One exception is central England, where the hottest summer remains 1976, although it may be challenged this year.

While extreme hot summers and heatwaves did happen in the past, they were less common. One big difference as far as England is concerned is that its extreme 1976 heatwave was a global outlier, whereas this year’s isn’t.

In 1976 northwestern Europe had higher temperature anomalies than almost anywhere else on the globe. In June 2018 the same region was unusually warm, but so was most of the rest of the Northern Hemisphere.

The ConversationSo while the persistent weather patterns are driving much of the extreme heat we’re seeing across the Northern Hemisphere, we know that human-caused climate change is nudging the temperatures up and increasing the odds of new heat extremes.

Andrew King, ARC DECRA fellow, University of Melbourne and Ben Henley, Research Fellow in Climate and Water Resources, University of Melbourne

This article was originally published on The Conversation. Read the original article.

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How to turn the waste crisis into a design opportunity



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David Lisbona/Flickr, CC BY-SA

Tom Lee, University of Technology Sydney; Berto Pandolfo, University of Technology Sydney; Nick Florin, University of Technology Sydney, and Rachael Wakefield-Rann, University of Technology Sydney

You might never have heard of expanded polystyrene, but you’ve definitely used it. It’s the lightweight white foam used for everything from packing peanuts to holding boxes of veggies at the supermarket.

Expanded polystyrene (EPS) is versatile, waterproof, and surprisingly strong. Unfortunately, it’s also a nightmare to dispose of. It fragments easily into many small, light pieces which can be easily carried away by the wind, and is difficult to process.




Read more:
We can’t recycle our way to ‘zero waste’


Australia exports some EPS to be recycled overseas, but we have less than one collection point per state. All of this means that The NSW Evironmental Protection Agency estimates that some 12,000 tonnes of EPS is sent to landfill every year. According to the Australian Plastics Recycling survey, about 14% of EPS is recovered for recycling. Most of that is exported – only around 1.6% of all the EPS used in Australia is recycled here.

This is why many researchers are looking for ways to re-purpose EPS, taking advantage of this very useful material and keeping it out of landfill.

Turning trash into treasure

Over the past seven weeks our Master of Design students at UTS have been working on this problem. On level two of the UTS tower, down in the carpark, is a piece of machinery that turns EPS into patties of hardened plastic. These are collected on a palette, taken to a processing facility, and turned into low grade industrial products like traffic bumpers.

EPS is fed into the machine at one end. It’s then shredded, heated, and pressed through an opening at the other end.

It coils into a messy sausage on the cement floor, before being quickly worked into a rough disk by a service worker using a rudimentary, rake-like tool. The spectacle is vaguely reminiscent of watching chefs work pizza dough. Every week cluttered stacks of EPS become these compact, easy-to-handle patties.

Artist Peter Trimble uses a similar method to create Rubbish Stools out of EPS. The process removes the air from the material, reducing it to 3-5% of its original volume.

A different kind of meaning emerges when this substance, rather than piling up in an inchoate lump on the floor, transforms into something useful: a chair, bowl, or tray.

Design and systemic change

Design involves finding ways to create value and meaning with materials that might otherwise remain inconspicuous and neglected. Rather than dismiss EPS as redundant packaging, we aim to see it as something with its own inherent functional and aesthetic value.

In their initial experiments my design students discovered that EPS can be a beautiful material. Through the application of heat and use of specific moulds, EPS can take on an organic, porous texture, reminiscent of bone, or an immaculate, plastic sheen, almost like glass.

This intensity of contrast is one of the common attributes of aesthetic beauty. It could easily be turned into an object, such as a vase or bowl, that someone might hold onto for life.

Considered in isolation, these insights are of limited value to a sustainable Australia. It doesn’t help that many people if the UTS gift store begins selling items made from recycled material (although obviously it is a very small improvement).

However, if these things find their way to landfill soon after purchase the sustainability benefit is marginal.




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If we can’t recycle it, why not turn our waste plastic into fuel?


The more significant change comes when good design helps create a broader shift. For example, could UTS change its recycling systems to accommodate a range of ongoing projects, designed to supply the needs of the university community?

Better still, could those results be applied to large shopping centres, local councils, or small towns? Sometimes seeing the beauty in an overlooked piece of rubbish can open our minds to many different possibilities.


The ConversationThe authors would like to acknowledge Andrew Simpson, founder of Vert Design, for his guidance and teaching expertise in the student project.

Tom Lee, Lecturer, Faculty of Design and Architecture Building, University of Technology Sydney; Berto Pandolfo, Senior Lecturer Product Design, University of Technology Sydney; Nick Florin, Research Director, Institute for Sustainable Futures, University of Technology Sydney, and Rachael Wakefield-Rann, Research Consultant and PhD Candidate, Institute for Sustainable Futures, University of Technology Sydney

This article was originally published on The Conversation. Read the original article.

A numbers game: killing rabbits to conserve native mammals



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Controlling rabbit populations has a key role in conserving Australia’s native plants and animals
William Booth

Euan Ritchie, Deakin University; Damien Fordham, University of Adelaide, and Miguel Lurgi, Centre national de la recherche scientifique (CNRS)

Invasive species have a devastating effect on biodiversity. In Australia, introduced red foxes and feral cats have been implicated in the majority of the extinctions of the native mammal fauna, which has been decimated since European arrival.

But there’s a herbivore that also causes eco-catastrophe. Rabbits both compete with native animals for food and shelter and act as easy prey for abundant populations of cats and foxes. By over-grazing vegetation and reducing habitat complexity, they make hunting easier for introduced predators.




Read more:
Invasive predators are eating the world’s animals to extinction – and the worst is close to home


Food webs are complex. Because of this, once an invasive species is embedded in a food web, simply eradicating them without considering the potential knock-on effects to other species they interact with, could cause unintended and undesirable consequences. We modelled different rates of rabbit population reduction to assess what level of control might be best for aiding the conservation of native mammals and not causing negative outcomes.

Rabbit numbers boom and crash

Rabbits, famously, reproduce rapidly and can cope with a relatively high predation rate. This can cause “hyper-predation”, where rabbit-inflated cat and fox populations indirectly increase the predation pressure on native mammals. This is especially so when rabbit populations intermittently crash due to, for example, extreme environmental events (like severe and prolonged droughts) or disease. This causes predators to switch their diet and eat more native mammals.

Threatened species such as the greater bilby are likely to benefit from rabbit control.
Jasmine Vink

This logically suggests that reducing rabbit numbers might thus help reduce cat and fox populations, by removing their abundant prey. Collectively this should benefit native plants and animals, including many threatened mammal species. However, ecosystem and pest management is a complex game.

When controlling rabbits we need to look beyond one or two species. We should consider the potential consequences for the entire ecological community, which ultimately depend on how changes in one species percolate through the network of ecological interactions between them.

Our new research, recently published in the Journal of Applied Ecology, set out to examine these questions in more detail. We consider other key players in Australia’s arid regions, such as kangaroos and dingoes, when looking at the effects of rabbit control on small native mammals. Our aim was to provide a better understanding of how changes in rabbit populations might affect other species via the food web.

We developed a multi-species ecological network model to describe and quantify how changing rabbit abundance can affect species on different feeding levels. In addition to rabbits, small native mammals, and mesopredators (cats and foxes), our model also considers apex predators (dingo) and large herbivores (kangaroo) as part of the Australian arid food web. This model allowed us to examine changes in predator-prey interactions (including potential prey switching and hyper-predation) and how these could affect the survival of native prey through time.

Our model of an Australian arid ecosystem food web.
Author provided

We found that removing rabbits at rates between 30-40% appeared to benefit small mammals. This is approximately the rate at which rabbits are currently managed in Australia using biocontrol agents (introduced diseases).

Rabbit control in Australia typically involves a “press and pulse” approach. Rabbit populations are suppressed via biocontrol (press) and periods of warren destruction and poisoning (pulse). Finding that reducing rabbit populations by around 40% seems most beneficial to small mammals is important, as it informs how and when we combine these strategies.

The 40% rate corresponds well with the disease-induced (press) mortality rate in rabbit populations due to rabbit haemorrhagic disease and myxomatosis. These are the primary biocontrol agents used in arid Australia to control rabbit populations.

Our study supports rabbit-reduction strategies that involve sustained “press” control, that kill a moderate portion of a rabbit population, with less frequent removal at higher proportions of the population.

To effectively manage invasive species, it’s important to focus on entire communities. Targeting single species might not be enough – every animal exists within a complex web of interactions.




Read more:
Mourn our lost mammals, while helping the survivors battle back


There has been much focus by the current government on controlling feral cats, as a way to conserve many of Australia’s unique and threatened mammal species.

The ConversationHowever, more focus could be devoted to protecting habitat cover and complexity, by reducing the land clearing and over-grazing that makes hunting easier. We can also manage rabbits sensibly to reduce competition for resources, and indirectly control cats and foxes.

Euan Ritchie, Associate Professor in Wildlife Ecology and Conservation, Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University; Damien Fordham, , University of Adelaide, and Miguel Lurgi, Postdoctoral research fellow, Centre national de la recherche scientifique (CNRS)

This article was originally published on The Conversation. Read the original article.