11,000 scientists warn: climate change isn’t just about temperature



Land clearing, cattle populations and carbon emissions stand alongside temperature as important measures of climate change.
DAN PELED/AAP

Thomas Newsome, University of Sydney and William Ripple, Oregon State University

Exactly 40 years ago, a small group of scientists met at the world’s first climate conference in Geneva. They raised the alarm about unnerving climate trends.

Today, more than 11,000 scientists have co-signed a letter in the journal BioScience, calling for urgently necessary action on climate.

This is the largest number of scientists to explicitly support a publication calling for climate action. They come from many different fields, reflecting the harm our changing climate is doing to every part of the natural world.




Read more:
40 years ago, scientists predicted climate change. And hey, they were right


Why no change?

If you’re thinking not much has changed in the past 40 years, you might be right. Globally, greenhouse gas emissions are still rising, with increasingly damaging effects.

Much of the focus to date has been on tracking global surface temperatures. This makes sense, as goals like “prevent 2℃ of warming” create a relatively simple and easy-to-communicate message.

However, there’s more to climate change than global temperature.

In our paper, we track a broader set of indicators to convey the effects of human activities on greenhouse gas emissions, and the consequent impacts on climate, our environment, and society.

The indicators include human population growth, tree cover loss, fertility rates, fossil fuel subsidies, glacier thickness, and frequency of extreme weather events. All are linked to climate change.

Troubling signs over the past 40 years

Profoundly troubling signs linked to human activities include sustained increases in human and ruminant populations, global tree cover loss, fossil fuel consumption, number of plane passengers, and carbon dioxide emissions.

The concurrent trends on the actual impacts of climate change are equally troubling. Sea ice is rapidly disappearing, and ocean heat, ocean acidity, sea level, and extreme weather events are all trending upwards.

These trends need to be closely monitored to assess how we are responding to the climate emergency. Any one of them could hit a point of no return, creating a catastrophic feedback loop that could make more regions of Earth uninhabitable.




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The need for better reporting

We urge national governments to report on how their own results are trending. Our indicators will allow policymakers and the public to better understand the magnitude of this crisis, track progress, and realign priorities to alleviate climate change.

Some of the indicators could even be presented monthly to the public during news broadcasts, as they are arguably more important than the trends in the stock exchange.

It’s not too late to act

In our paper we suggest six critical and interrelated steps that governments, and the rest of humanity, can take to lessen the worst effects of climate change:

  1. prioritise energy efficiency, and replace fossil fuels with low-carbon renewable energy sources,

  2. reduce emissions of short-lived pollutants like methane and soot,

  3. protect and restore the Earth’s ecosystems by curbing land clearing,

  4. reduce our meat consumption,

  5. move away from unsustainable ideas of ever-increasing economic and resource consumption, and

  6. stabilise and ideally, gradually reduce human populations while improving human well-being.

We recognise that many of these recommendations are not new. But mitigating and adapting to climate change will entail major transformations across all six areas.

How can you help?

Individuals can make a difference by reducing meat consumption, voting for political parties and members of government bodies who have clear climate change policies, rejecting fossil fuels where possible, using renewable and clean sources of energy, reducing car and air travel, and joining citizen movements.

Lots of small changes will help inspire larger scale shifts in policy and economic frameworks.

We are encouraged by a recent global surge of concern. Some governments are declaring climate emergencies. Grassroots citizen movements are demanding change.




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As scientists, we urge widespread use of our indicators to track how changes across the six areas above will start to change our ecosystem trajectories.The Conversation

Thomas Newsome, Lecturer, University of Sydney and William Ripple, Distinguished Professor and Director, Trophic Cascades Program, Oregon State University

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

‘This situation brings me to despair’: two reef scientists share their climate grief



A researcher completing bleaching surveys in the southern Great Barrier Reef after a major bleaching event.
ARC CENTRE OF EXCELLENCE FOR CORAL REEF STUDIES

Jon Brodie, James Cook University and Alana Grech, James Cook University

Few feel the pain of the Great Barrier Reef’s decline more acutely than the scientists trying to save it. Ahead of next week’s UN climate summit, two researchers write of their grief, and hope.

Jon Brodie

Professorial Fellow, ARC Centre of Excellence for Coral Reef Studies, James Cook University

As I write this, much of inland eastern Australia is enduring what is likely to be the worst drought ever recorded. Bushfires are devastating parts of New South Wales and southern Queensland, tearing through rainforest that should not be dry enough to burn. Major towns will probably soon run out of water. The condition of the vital Murray-Darling river system is dire.

Some federal government MPs have responded by questioning whether these events are linked to anthropogenic, or man-made, climate change. Others deny the science outright. Now we have a politically motivated Senate inquiry into water quality on the Great Barrier Reef.

This situation brings me to despair. For the past 45 years I have researched and managed coral reef water quality in Australia and overseas. Now 72, I see that much of my work, and that of my colleagues, has not led to a bright future for coral reefs. In decades to come they will probably still contain some corals, but ecologically speaking they will not be growing, or even functioning.

Coral bleaching at Lizard Island on the Great Barrier Reef in 2016.
XL CATLIN SEAVIEW SURVEY

Official assessments appear to confirm the reef’s inexorable demise. A five-yearly outlook report from the Great Barrier Reef Marine Park Authority this month declared the outlook was “very poor” – a decline from “poor” in 2014. A joint federal-Queensland government report released on the same day found “minimal progress” in addressing water quality – the second most serious threat to the reef.




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The United Nations Intergovernmental Panel on Climate Change warned in October last year that a global temperature rise of 2℃ above pre-industrial levels will decimate coral growth. It said we must stay below 1.5℃ of warming for coral reefs to have a reasonable chance for a future.

Flood plume extending 60km offshore after an extreme monsoon weather event, February 2019. Such events can seriously damage water quality.
Matt Curnock

About 1.2℃ of this warming has already occurred; on current policies, the world is on track for a 3℃ temperature rise.

I feel guilty when discussing this situation with young scientists. I worry that my legacy is such that they will spend their professional lives studying and documenting the terminal decline of coral reefs.

I feel the same sense of guilt towards my 19-year-old grandson, who is in his first year of university studying mathematics. The outlook is grim, not just for coral reefs but for society in general.

My life’s work, spent mostly outside, has taken a toll on my health. I’ve had several skin cancers excised over the past 25 years and in recent years have undergone major skin cancer surgery. I have recovered well and still come to James Cook University every day. But the combination of ill-health, coupled with political inaction over the dire state of the environment, only compounds a feeling that I can’t really make a difference anymore.




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But on a more positive note, the Great Barrier Reef is more than just coral. It includes a wonderful array of seagrass, dugongs, turtles, fish, dolphins, birds, and whales – and this is not a complete list.

Many of these species are also in decline. But good water quality management will, for example, help encourage the growth of seagrass on which dugongs and green turtles rely for food. The overall picture may be grim, but there are small spots of hope.

A researcher surveys the aftermath of coral bleaching at Lizard Island on the Great Barrier Reef in 2016.
XL CATLIN SEAVIEW

Alana Grech

Assistant Director, ARC Centre of Excellence for Coral Reef Studies, James Cook University

I spent last weekend on Magnetic Island, just a short ferry ride from my Townsville home. With great joy I sat with our infant under a beach tent and watched my older son happily snorkel among the corals and fish.

The intergenerational inequalities posed by climate change have become all the more real since I became a mum. The reef my son swam over is fundamentally different from reefs that existed when my parents were children, and they are continuing to change.

As the wet season approaches, my anxiety, and that of my colleagues, increases at the prospect of another extreme marine heatwave. Two consecutive summers of coral bleaching in 2016 and 2017 severely damaged two-thirds of the Great Barrier Reef. Some researchers who bore witness to these events experienced “ecological grief”: a profound sense of loss at the environmental harm that global warming brings.

Damage to the Great Barrier Reef threatens the region’s economy, including the fishing and tourism industries.
AAP

In much the same way, a large proportion of north Queensland residents and tourists experience significant grief associated with coral bleaching and mortality. Biodiversity loss also affects Traditional Owners, impacting their connection to Sea Country.

Extreme weather events associated with climate change jeopardise the tourism and fishing industries, and coastal infrastructure that underpin the region’s economy. Insurance premiums are already higher in northern Australia than in the rest of the country, and some places may one day become uninsurable.

However, my children were born in a wealthy country that is likely to withstand and recover from climate impacts that affect their basic needs. This privilege is not shared by the majority of reef-dependent coastal communities in the world’s tropics.

Fijian Prime Minister Frank Bainimarama warns: “Our region remains on the front line of humanity’s greatest challenges”

I come from a family of healthcare professionals, but felt a career in environmental science offered the potential to make a broader impact. The state of the planet and human health and well-being are inextricably linked.

I continue to be motivated by my research on the Great Barrier Reef. But I am deeply concerned about rising mistrust in the scientific process, despite unequivocal evidence of the reef’s decline and the impacts of climate change. It is particularly distressing when members of the federal government undermine the science that informs their own policies – including North Queensland politicians advocating for a national watchdog to verify scientific papers.

Clownfish in the Great Barrier Reef. Sediment is damaging fish gills and causing disease.
AAP/James Cook University

If our political leaders want to support community adaptation and resilience to climate change, they should build, rather than erode, public trust in the evidence that underpins reef management and policy.


This piece is part of Covering Climate Now, a global collaboration of more than 250 news outlets to strengthen coverage of the climate story.The Conversation

Jon Brodie, Professorial Fellow, ARC Centre of Excellence for Coral Reef Studies, James Cook University and Alana Grech, Assistant Director, ARC Centre of Excellence for Coral Reef Studies, James Cook University

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

40 years ago, scientists predicted climate change. And hey, they were right



It’s been four decades since the first credible, global report on the effect of carbon dioxide on the global climate.
Shutterstock

Neville Nicholls, Monash University

This month the world has been celebrating the 50th anniversary of Neil Armstrong setting foot on the Moon. But this week sees another scientific anniversary, perhaps just as important for the future of civilisation.

Forty years ago, a group of climate scientists sat down at Woods Hole Oceanographic Institution in Massachusetts for the first meeting of the “Ad Hoc Group on Carbon Dioxide and Climate”. It led to the preparation of what became known as the Charney Report – the first comprehensive assessment of global climate change due to carbon dioxide.




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It doesn’t sound as impressive as landing on the Moon, and there certainly weren’t millions waiting with bated breath for the deliberations of the meeting.

But the Charney Report is an exemplar of good science, and the success of its predictions over the past 40 years has firmly established the science of global warming.

What is this ‘greenhouse gas’ you speak of?

Other scientists, starting in the 19th century, had already demonstrated that carbon dioxide was what we now call a “greenhouse gas”. By the 1950s, scientists were predicting warming of several degrees from the burning of fossil fuels. In 1972 John Sawyer, the head of research at the UK Meteorological Office, wrote a four-page paper published in Nature summarising what was known at the time, and predicting warming of about 0.6℃ by the end of the 20th century.

But these predictions were still controversial in the 1970s. The world had, if anything, cooled since the middle of the 20th century, and there was even some speculation in the media that perhaps we were headed for an ice age.

The meeting at Woods Hole gathered together about 10 distinguished climate scientists, who also sought advice from other scientists from across the world. The group was led by Jule Charney from the Massachusetts Institute of Technology, one of the most respected atmospheric scientists of the 20th century.

The Report lays out clearly what was known about the likely effects of increasing carbon dioxide on the climate, as well as the uncertainties. The main conclusion of the Report was direct:

We estimate the most probable warming for a doubling of CO₂ to be near 3℃ with a probable error of 1.5℃.

In the 40 years since their meeting, the annual average CO₂ concentration in the atmosphere, as measured at Mauna Loa in Hawaii, has increased by about 21%. Over the same period, global average surface temperature has increased by about 0.66℃, almost exactly what could have been expected if a doubling of CO₂ produces about 2.5℃ warming – just a bit below their best estimate. A remarkably prescient prediction.


Author provided/The Conversation, CC BY-ND

Reception of the article

Despite the high regard in which the authors of the Charney Report were held by their scientific peers at the time, the report certainly didn’t lead to immediate changes in behaviour, by the public or politicians.

But over time, as the world has continued to warm as they predicted, the report has become accepted as a major milestone in our understanding of the consequences our actions have for the climate. The current crop of climate scientists revere Charney and his co-authors for their insight and clarity.

Strong science

The report exemplifies how good science works: establish an hypothesis after examining the physics and chemistry, then based on your assessment of the science make strong predictions. Here, “strong predictions” means something that would be unlikely to come true if your hypothesis and science were incorrect.

In this case, their very specific prediction was that warming of between 1.5℃ and 4.5℃ would accompany a doubling of atmospheric CO₂. At the time, global temperatures, in the absence of their hypothesis and science, might have been expected to stay pretty much the same over the ensuing 40 years, cooled a bit, possibly even cooled a lot, or warmed a lot (or a little).

In the absence of global warming science any of these outcomes could have been feasible, so their very specific prediction made for a very stringent test of their science.

The Charney Report’s authors didn’t just uncritically summarise the science. They also acted sceptically, trying to find factors that might invalidate their conclusions. They concluded:

We have tried but have been unable to find any overlooked or underestimated physical effects that could reduce the currently estimated global warmings due to a doubling of atmospheric CO₂ to negligible proportions or to reverse them altogether.

The report, and the successful verification of its prediction, provides a firm scientific basis for the discussion of what we should do about global warming.

Over the ensuing 40 years, as the world warmed pretty much as Charney and his colleagues expected, climate change science improved, with better models that included some of the factors missing from their 1979 deliberations.




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This subsequent science has, however, only confirmed the conclusions of the Charney Report, although much more detailed predictions of climate change are now possible.The Conversation

Neville Nicholls, Professor emeritus, School of Earth, Atmosphere and Environment, Monash University

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

Sit! Seek! Fly! Scientists train dogs to sniff out endangered insects


Julia Mynott, La Trobe University

Three very good dogs – named Bayar, Judd and Sasha – have sniffed out the endangered Alpine Stonefly, one of the smallest animals a dog has been trained to successfully detect in its natural habitat.

The conservation of threatened species is frequently hampered by the lack of relevant data on their distributions. This is particularly true for insects, where the difficulty of garnering simple information means the threatened status of many species remains unrecognised and unmanaged.




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In alpine areas there is a pressing need for innovative methods to better reveal the distribution and abundance of threatened insects.

Alpine regions rely on cool temperatures, and since climate change will bring warmer weather and lower rainfalls, insects like the Alpine Stonefly, which lives in the alpine freshwater system, will struggle to survive.

And while insects might not be appealing to everyone, they are extremely important for ecosystem function.

Traditional survey detection methods are often labour intensive, and hard-to-find species provide limited information. This is where the labrador, border collie and samoyed came to the rescue.

La Trobe’s Anthrozoology Research Group Dog Lab in Bendigo, Victoria have been training a pool of local community volunteers and their dogs in conservation detection to use with environmental DNA sampling. Using both environmental DNA and detection dogs has the potential to generate a lot of meaningful data on these threatened stoneflies.

For seven weeks in a special program, dogs were trained to memorise the odour of the Alpine Stonefly (Thaumatoperla alpina), a threatened but iconic insect in the high plains.

The dogs have previously been trained to sniff out animal nests or faeces but not an animal itself, so this was a new approach and an Australian first.

Stoneflies are hard to catch

The Alpine Stonefly are brightly coloured aquatic insects and are difficult to find, especially as larvae in water where they live as predators for up to two years in the streams on the Bogong High Plains, Mount Buller-Mount Stirling, Mt Baw Baw and the Yarra Ranges.

They often burrow underneath cobbles, boulders and into the stream bed while the adults only emerge from the water for a few months between January and April to reproduce.

With all this in mind, it’s easy to understand why traditional detection methods can be time consuming and often ineffective.

We predominately focused on the endangered Alpine Stonefly, found across the Bogong High Plains. Their restricted distribution and habitat made them an ideal candidate to trial detection dogs and environmental DNA techniques.




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We need a bank of DNA from dirt and water to protect Australia’s environment


How dogs and environmental DNA help

We collected water samples from across the Bogong High Plains, Mount Buller and Mount Stirling with trace DNA, such as cells shed from the insect. The ability to quickly take these samples from a broad area to indicate the presence of a species is important to understand distribution. But this approach limits the amount of ecological information that is gathered.

Initial training introduced the dogs to the odour of the Alpine Stonefly in a controlled laboratory setting. Then they graduated from the laboratory to small areas of bushland to search for the insect.

Once the dogs successfully completed their training, it was time to trial the dogs in the alpine environment and survey Alpine Stoneflies in their natural environment.

The trial was conducted at Falls Creek with the dogs’ three volunteer handlers. And the surveys were successful, with all three dogs finding Alpine Stoneflies in their natural habitats.

So could this success be transferred to a similar species?

Absolutely. In preliminary trials, Bayar, Judd and Sasha detected the Stirling Stonefly, a related species of Thaumatoperla that lives in Mount Buller and Mount Stirling, suggesting detection dogs can transfer their conservation training from one species to another.

This is a great find as it means this technique can be used to survey yet another species of Thaumatoperla that lives in Mt Baw Baw and the Yarra Ranges.




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Our research is showing that these new sampling techniques supporting conservation are an important part of keeping biodiversity protected in alpine regions.

Now that we’ve successfully trained three dogs, we’re hoping to secure funding to conduct future and more thorough surveys on the Alpine and Stirling Stonefly, and eventually on the third species of stonefly.

By developing creative techniques to detect these species, we boost our ability to document them and, importantly, to protect them.The Conversation

Julia Mynott, Research Officer, Centre for Freshwater Ecosystems, La Trobe University

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

To reduce fire risk and meet climate targets, over 300 scientists call for stronger land clearing laws



File 20190308 150700 3qu1wc.jpg?ixlib=rb 1.1
Without significant tree cover, dry and dusty landscapes can result.
Don Driscoll, Author provided

Martine Maron, The University of Queensland; Andrea Griffin, University of Newcastle; April Reside, The University of Queensland; Bill Laurance, James Cook University; Don Driscoll, Deakin University; Euan Ritchie, Deakin University, and Steve Turton, CQUniversity Australia

Australia’s high rates of forest loss and weakening land clearing laws are increasing bushfire risk, and undermining our ability to meet national targets aimed at curbing climate change.

This dire situation is why we are among the more than 300 scientists and practitioners who have signed a declaration calling for governments to restore, or better strengthen regulations to protect native vegetation.




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Land clearing on the rise as legal ‘thinning’ proves far from clear-cut


Land clearing laws have been contentious in several states for years. New South Wales relaxed its land clearing controls in 2017, triggering concerns over irreversible environmental damage. Although it is too early to know the impact of those changes, a recent analysis found that land clearing has increased sharply in some areas since the laws changed.

The Queensland Labor government’s 2018 strengthening of land clearing laws came after years of systematic weakening of these protections. Yet the issue has remained politically divisive. While discussing a federal inquiry into the impact of these policies on farmers, federal agriculture minister David Littleproud suggested that the strenthening of regulations may have worsened Queensland’s December bushfires.

We argue such an assertion is at odds with scientific evidence. And, while the conservation issues associated with widespread land clearing are generally well understood by the public, the consequences for farmers and fire risks are much less so.

Tree loss can increase fire risk

During December’s heatwave in northern Queensland, some regions were at “catastrophic” bushfire risk for the first time since ratings began. Even normally wet rainforests, such as at Eungella National Park inland from Mackay, sustained burns in some areas during “unprecedented” fire conditions.

There is no evidence to support the suggestion that 2018’s land clearing law changes contributed to the fires. No changes were made to how vegetation can be managed to reduce fire risk. This is governed under separate laws, which remained unaltered.

In fact, shortly after the fires, Queensland’s land clearing figures were released. They showed that in the three years to June 2018, an area equivalent to roughly 570,000 Melbourne Cricket Grounds (1,138,000 hectares) of bushland was cleared, including 284,000 hectares of remnant (old-growth) ecosystems.

Tree clearing can worsen fire risk in several ways. It can affect the regional climate. In parts of eastern Australia, tree cover reductions are estimated to have increased summer surface temperatures by up to 2℃ and southwest Western Australia by 0.4–0.8℃, reduced rainfall in southeast Australia, and made droughts hotter and longer.

Removing forest vegetation depletes soil moisture. Large, intact areas of forest typically have cooler, wetter microclimates buffered from extreme temperatures. Over time, some forest types can even become fire-resistant, but smaller patches of trees are typically drier and more flammable.

Trees also form a natural windbreak that can slow the spread of bushfires. An analysis of the 2005 Wangary fire in South Australia found that fires spread most rapidly through paddocks, rather than through areas lined with native trees.

Trends from 1978 to 2017 in the annual (July to June) sum of the daily Forest Fire Danger Index, an indicator of the severity of fire weather conditions. Positive trends, shown in the yellow to red colours, indicate increasing length and intensity of the fire weather season. Areas where there are sparse data coverage, such as central parts of Western Australia, are faded.
CSIRO/Bureau of Meteorology/State of the Climate 2018

Finally, Australia’s increasing risk of bushfire and worsening drought are driven by global climate change, to which land clearing is a major contributor.

Farmers on the frontline of environmental risk

Extensive tree clearing also leads to problems for farmers, including rising salinity, reduced water quality, and soil erosion. Governments and rural communities spend significant money and labour redressing the aftermath of excessive clearing.

Sensible regulation of native vegetation removal does not restrict existing agriculture, but rather seeks to support sustainable production. Retained trees can help deal with many environmental risks that hamper agricultural productivity, including animal health, long-term pasture productivity, risks to the water cycle, pest control, and human well-being.

Rampant tree clearing is undoing climate policy too. Much of the federal government’s A$2.55 billion Emissions Reduction Fund has gone towards tree planting. But it would take almost this entire sum just to replace the trees cleared in Queensland since 2012.




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In 2019, Australians might reasonably expect that our relatively wealthy and well-educated country has moved beyond a frontier-style reliance on continued deforestation, and we would do well to better acknowledge and learn lessons from Indigenous Australians with respect to their land management practices.

Yet the periodic weakening of land clearing laws in many parts of Australia has accelerated the problem. The negative impacts on industry, society and wildlife are numerous and well established. They should not be ignored.The Conversation

Martine Maron, ARC Future Fellow and Associate Professor of Environmental Management, The University of Queensland; Andrea Griffin, Senior Lecturer, School of Psychology, University of Newcastle; April Reside, Researcher, Centre for Biodiversity and Conservation Science, The University of Queensland; Bill Laurance, Distinguished Research Professor and Australian Laureate, James Cook University; Don Driscoll, Professor in Terrestrial Ecology, Deakin University; Euan Ritchie, Associate Professor in Wildlife Ecology and Conservation, Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University, and 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.

Scientists are developing greener plastics – the bigger challenge is moving them from lab to market



File 20180813 2915 3vl524.jpg?ixlib=rb 1.1
Used once and done.
Michael Coghlan, CC BY-SA

Richard Gross, Rensselaer Polytechnic Institute

Synthetic plastics have made many aspect of modern life cheaper, safer and more convenient. However, we have failed to figure out how to get rid of them after we use them.

Unlike other forms of trash, such as food and paper, most synthetic plastics cannot be easily degraded by live microorganisms or through chemical processes. As a result, a growing plastic waste crisis threatens the health of our planet. It is embodied by the Great Pacific Garbage Patch – a massive zone of floating plastic trash, three times the size of France, stretching between California and Hawaii. Scientists have estimated that if current trends continue, the mass of plastics in the ocean will equal the mass of fish by 2050. Making plastics from petroleum also increases carbon dioxide levels in the atmosphere, contributing to climate change.

Much of my work has been dedicated to finding sustainable ways to make and break down plastics. My lab and others are making progress on both fronts. But these new alternatives have to compete with synthetic plastics that have established infrastructures and optimized processes. Without supportive government policies, innovative plastic alternatives will have trouble crossing the so-called “valley of death” from the lab to the market.

From wood and silk to nylon and plexiglass

All plastics consist of polymers – large molecules that contain many small units, or monomers, joined together to form long chains, much like strings of beads. The chemical structure of the beads and the bonds that join them together determine polymers’ properties. Some polymers form materials that are hard and tough, like glass and epoxies. Others, such as rubber, can bend and stretch.

A monomer of Teflon, a nonstick synthetic resin (top), and a chain of monomers (bottom).
Chromatos

For centuries humans have made products out of polymers from natural sources, such as silk, cotton, wood and wool. After use, these natural plastics are easily degraded by microorganisms.

Synthetic polymers derived from oil were developed starting in the 1930s, when new material innovations were desperately needed to support Allied troops in World War II. For example, nylon, invented in 1935, replaced silk in parachutes and other gear. And poly(methyl methacrylate), known as Plexiglas, substituted for glass in aircraft windows. At that time, there was little consideration of whether or how these materials would be reused.

Modern synthetic plastics can be grouped into two main families: Thermoplastics, which soften on heating and then harden again on cooling, and thermosets, which never soften once they have been molded. Some of the most common high-volume synthetic polymers include polyethylene, used to make film wraps and plastic bags; polypropylene, used to form reusable containers and packaging; and polyethylene terephthalate, or PET, used in clothes, carpets and clear plastic beverage bottles.

Recycling challenges

Today only about 10 percent of discarded plastic in the United States is recycled. Processors need an input stream of non-contaminated or pure plastic, but waste plastic often contains impurities, such as residual food.

Batches of disposed plastic products also may include multiple resin types, and often are not consistent in color, shape, transparency, weight, density or size. This makes it hard for recycling facilities to sort them by type.

Melting down and reforming mixed plastic wastes creates recycled materials that are inferior in performance to virgin material. For this reason, many people refer to plastic recycling as “downcycling.”

As most consumers know, many plastic goods are stamped with a code that indicates the type of resin they are made from, numbered one through seven, inside a triangle formed by three arrows. These codes were developed in the 1980s by the Society of the Plastics Industry, and are intended to indicate whether and how to recycle those products.


Filtre

However, these logos are highly misleading, since they suggest that all of these goods can be recycled an infinite number of times. In fact, according to the Environmental Protection Agency, recycling rates in 2015 ranged from a high of 31 percent for PET (SPI code 1) to 10 percent for high-density polyethylene (SPI code 2) and a few percent at best for other groups.

In my view, single-use plastics should eventually be required to be biodegradable. To make this work, households should have biowaste bins to collect food, paper and biodegradable polymer waste for composting. Germany has such a system in place, and San Francisco composts organic wastes from homes and businesses.

Designing greener polymers

Since modern plastics have many types and uses, multiple strategies are needed to replace them or make them more sustainable. One goal is making polymers from bio-based carbon sources instead of oil. The most readily implementable option is converting carbon from plant cell walls (lignocellulosics) into monomers.

As an example, my lab has developed a yeast catalyst that takes plant-derived oils and converts them to a polyester that has properties similar to polyethylene. But unlike a petroleum-based plastic, it can be fully degraded by microorganisms in composting systems.

It also is imperative to develop new cost-effective routes for decomposing plastics into high-value chemicals that can be reused. This could mean using biological as well as chemical catalysts. One intriguing example is a gut bacterium from mealworms that can digest polystyrene, converting it to carbon dioxide.

Other scientists are developing high-performance vitrimers – a type of thermoset plastic in which the bonds that cross-link chains can form and break, depending on built-in conditions such as temperature or pH. These vitrimers can be used to make hard, molded products that can be converted to flowable materials at the end of their lifetimes so they can be reformed into new products.

It took years of research, development and marketing to optimize synthetic plastics. New green polymers, such as polylactic acid, are just starting to enter the market, mainly in compost bags, food containers, cups and disposable tableware. Manufacturers need support while they work to reduce costs and improve performance. It also is crucial to link academic and industrial efforts, so that new discoveries can be commercialized more quickly.

The ConversationToday the European Union and Canada provides much more government support for discovery and development of bio-based and sustainable plastics than the United States. That must change if America wants to compete in the sustainable polymer revolution.

Richard Gross, Professor of Chemistry, Rensselaer Polytechnic Institute

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

Scientists create new building material out of fungus, rice and glass


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Fungal bricks have the potential to create safer and more sustainable buildings.
V Anisimov / Shutterstock

Tien Huynh, RMIT University and Mitchell Jones, RMIT University

Would you live in a house made of fungus? It’s not just a rhetorical question: fungi are the key to a new low-carbon, fire-resistant and termite-deterring building material.

This type of material, known as a mycelium composite, uses the Trametes versicolor fungus to combine agricultural and industrial waste to create lightweight but strong bricks. It’s cheaper than synthetic plastics or engineered wood, and reduces the amount of waste that goes to landfill.




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Affordable, sustainable, high-quality urban housing? It’s not an impossible dream


What a fun guy

Fungal brick prototypes made from rice hulls and glass fines waste.
Tien Huynh, Author provided

Working with our colleagues, we used fungus to bind rice hulls (the thin covering that protects rice grains) and glass fines (discarded, small or contaminated glass). We then baked the mixture to produce a new, natural building material.

Making these fungal bricks is a low-energy and zero-carbon process. Their structure means they can be moulded into many shapes. They are therefore suited to a variety of uses, particularly in the packaging and construction industries.

A staple crop for more than half the world’s population, rice has an annual global consumption of more than 480 million metric tonnes and 20% of this is comprised of rice hulls. In Australia alone, we generate about 600,000 tonnes of glass waste a year. Usually these rice hulls and glass fines are incinerated or sent to landfill. So our new material offers a cost-effective way to reduce waste.

Fire fighter

Fungal bricks make ideal fire-resistant insulation or panelling. The material is more thermally stable than synthetic construction materials such as polystyrene and particleboard, which are derived from petroleum or natural gas.

Rice hulls, glass fines and the mixture of rice, glass and fungus, before baking.
Wikipedia/Tien Huynh, Author provided

This means that fungal bricks burn more slowly and with less heat, and release less smoke and carbon dioxide than their synthetic counterparts. Their widespread use in construction would therefore improve fire safety.

Thousands of fires occur every year and the main causes of fatalities are smoke inhalation and carbon monoxide poisoning. By reducing smoke release, fungal bricks could allow more time for escape or rescue in the event of a fire, thus potentially saving lives.




Read more:
How can we build houses that better withstand bushfires?


Bug battler

Termites are a big issue: more than half of Australia is highly susceptible to termite infestations. These cost homeowners more than A$1.5 billion a year.

Our construction material could provide a solution for combating infestations, as the silica content of rice and glass would make buildings less appetising to termites.




Read more:
Hidden housemates: the termites that eat our homes


The use of these fire-and-termite-resistant materials could simultaneously revolutionise the building industry and improve waste recycling.

Figure 3. Termite infestation zones in Australia.
termitesonline.com.au, Author provided

This is an exciting time to get creative about our waste. With China no longer buying Australia’s recycling – and new rules reducing plastic use in Australian supermarkets – we have the chance to move in line with communities in Japan, Sweden and Scotland that have near-zero waste.

Fungal bricks could be just one example of the creative thinking that will help us get there.


The Conversation


Read more:
The next step in sustainable design: Bringing the weather indoors


Tien Huynh, Senior Lecturer in the School of Sciences, RMIT University and Mitchell Jones, PhD Student, RMIT University

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