Commercial rock lobster and dive fisheries in parts of Tasmania’s south-east will be closed for three months to “mitigate trade risks” linked to antibiotic use by the salmon industry.
Larrakia custodians have appealed to the federal government to remediate heavy fuels and PFAS chemicals from a former Navy fuel storage base in Darwin before the land is returned to them.
Thousands of delegates, scientists and world leaders are gathered in Turkey for the latest United Nations climate summit, COP31. Their task is familiar: agree on how to cut greenhouse gas emissions and help countries cope with a warming planet.
But after more than three decades of negotiations, global emissions remain stubbornly high and the world is on course to overshoot the critical threshold of 1.5°C of warming. So have these annual summits actually achieved anything?
Dr Wesley Morgan, a climate diplomacy expert at UNSW Sydney, tells The Conversation Weekly podcast the answer is yes:
The Paris Agreement is a monumental diplomatic achievement.
Agreed in 2015, the treaty brought more than 190 countries together around shared climate goals. Morgan says it has helped shift the trajectory of global warming:
We were headed towards utter catastrophe. We’re still headed towards some very dire circumstances and more ambition is needed, but it is better than it would have been without this global agreement.
This year’s summit presents a particular diplomatic challenge for Australia because its climate and energy minister, Chris Bowen, is leading the negotiations.
Morgan says Australia can “tell a very positive story about what’s happening domestically in Australia”, including by pointing to significant strides in rooftop solar, which is now installed on one in three homes.
But Australia’s role as President of Negotiations at COP31 is controversial because Australia remains one of the world’s biggest exporters of coal and gas.
“It really is a tightrope,” Morgan says.
In September, the federal government approved an expansion of BHP’s Saraji coal mine in Queensland, while authorities in New South Wales gave the green light for a major Hunter Valley coal mine to keep operating until 2045.
The negotiations also face a major setback following the Trump administration’s withdrawal in January from international climate cooperation.
Yet Morgan notes that no other country has followed the United States out of the talks.
He points to the influence of Pacific island nations as evidence that smaller countries can shape global agreements. In 2015, The Republic of the Marshall Islands helped build the High Ambition Coalition, which was instrumental in securing the Paris Agreement and its 1.5°C goal.
For Pacific countries, Morgan says, that target is a matter of survival:
The rallying cry from the Pacific is 1.5 to stay alive.
One possible outcome from COP31 is a new global electrification target dubbed “35 by 35”: meeting 35% of the world’s final energy demand with electricity by 2035.
Morgan sees it as another step towards economies powered by clean energy – and despite the setbacks, he insists the transition is already underway:
There’s plenty of reasons for hope as well as reasons for despair.
Disclosure statement
Wesley Morgan is a fellow at the Climate Council of Australia.
Credits
This episode of The Conversation Weekly was written and produced by Miki Perkins and Grace Jennings-Edquist. Sound mixing by Michelle Macklem and theme music by Neeta Sarl. Ashlynne McGhee is head of editorial innovation. Gemma Ware is head of audio. Misha Ketchell and Stephen Kahn are editors-in-chief.
News clips in this episode from The Australian, ABC, CBS News, CBC News and NDTV Profit.
Listen to The Conversation Weekly via any of the apps listed above, download it directly via our RSS feed or find out how else to listen here. A transcript of this episode is available via the Apple Podcasts or Spotify apps.
Concrete is the most used human-made material on Earth. Billions of tonnes are produced every year.
Unfortunately, concrete is responsible for 5-8% of global carbon dioxide emissions. Concrete is typically made of sand, gravel and cement, the binding agent. The manufacturing of cement is the main reason why concrete is so high-emitting.
For two centuries, cement makers have relied on the Portland cement method. This requires heating limestone to about 1400°C in kilns. At these temperatures, limestone breaks down, releasing carbon dioxide. Kilns often run on coal or gas, which release even more CO? when burned.
Low-emissions concrete is entirely possible and it depends on substituting limestone cement with another binder. One of the best alternatives is geopolymer concrete, which often uses industrial byproducts. Emissions from geopolymers are up to 80% less than for Portland concrete. Australia has one of the largest geopolymer cement project in the world – Queensland’s Wellcamp Airport near Toowoomba, which used about 40,000 cubic metres of geopolymer cement.
But over a decade after the airport was built, geopolymer cement hasn’t taken off. Here’s why – and what we can do about it.
A polymer is a long molecule made up of repeating smaller chemical units. Geopolymers is the term for polymers made from minerals. They’re typically produced from mining byproducts such as clay or industrial byproducts such as fly ash and slag from blast furnaces. Alkaline chemicals such as sodium hydroxide are used as activators to convert these byproducts into a ceramic-like material able to bind together.
Australia produces about 10-15 million tonnes of fly ash a year – comparable to its annual cement consumption of about 11-12 million tonnes. Fly ash is challenging to dispose of and can become a major waste problem. Geopolymers offer a clever way to convert it into something valuable.
Australian companies such as Wagners (Queensland) and Zeobond (Victoria) started commercialising geopolymer cement in the 2000s. The 2014 construction of Wellcamp Airport by Wagners showed concrete without cement could be deployed at commercial scale.
Geopolymers have major advantages over traditional concrete. But there are major barriers to overcome.
One is a lack of long-term performance data. Cement concrete has 150 years of real-world evidence, while geopolymers have only been around since the 1980s. The construction industry can’t yet confidently guarantee or insure geopolymer structures.
Public infrastructure projects can help by trialling geopolymers and monitoring long-term performance. This would build the evidence base needed if the industry is to accept it.
In the meantime, there’s already enough evidence to show geopolymers are well suited for masonry, mortar, renders, plasters, paving and precast products.
Workability and handling is another challenge. Construction workers know how to handle cement-based concrete. But geopolymers have to be handled differently, as they can be corrosive until they set. This means they need extra safety measures and operator training. The way this concrete sets and hardens is also different to cement.
While Australia’s existing standards and operating procedures primarily focus on conventional concrete, geopolymer guidance has recently been released. More will need to be done to boost familiarity.
Variation in product quality is another major issue. Because geopolymers are often produced from industrial by-products, feedstock quality can vary significantly and give inconsistent results.
Fly ash is a good example. After coal is burned, it leaves this fine, powdery ash behind. But the ash itself differs depending on type of coal – brown coal (lignite) makes fly ash with more calcium while black coal (anthracite) produces ash with little calcium and more silica and alumina. These differences can lead to concrete with very different characteristics, from strength to setting time to durability.
Geopolymers can also be made from feedstocks such as mineral processing waste, which can give it useful properties such as resistance to acids.
For the industry to mature, it makes clear sense to classify geopolymers based on their precursor type. Kevlar and cling film are both made from plastic polymers, but it wouldn’t make sense to simply call them “polymers”.
Finding more feedstock options is sensible.
One final challenge is the local availability of feedstocks and chemical activators such as caustic soda and water glass (sodium silicate). Both of these can be produced in Australia, but supplies of fly ash depend on coal plants. As these retire, fly ash may become harder to source.
These technical challenges can be overcome. But large-scale adoption will mean overcoming a classic chicken-and-egg problem.
Concrete producers are reluctant to invest in large-scale geopolymer production if the demand isn’t there, while builders, developers and infrastructure firms are hesitant to rely on less familiar materials without established supply chains and a long-term history of performance.
Government procurement policies and demonstration projects could help solve the problem by creating early demand and building industry confidence.
Geopolymers are unlikely to replace cement any time soon. But as the construction industry seeks to reduce emissions, geopolymers have real promise.
With continued research, appropriate standards, targeted government support and stronger industry engagement, geopolymer concrete could play a significant role in Australia’s efforts to cut emissions, tackle industrial waste and make infrastructure more sustainable.
Mariam Darestani and other authors receive funding from SmartCrete CRC and Zeolite Australia. This funding has no bearing on the article's findings.
Bijan Markhali, Kazem Javan, and Pooja Kaur Chaggar do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.
Australian PM boasts of success in renewables but is criticised for not addressing the nation’s huge coal industry
Get our breaking news email, free app or daily news podcast
Anthony Albanese has said governments have a “solemn responsibility” to act on climate change in a historic speech to the UN’s climate summit, but he failed to mention the fossil fuels driving the crisis.
The Australian prime minister landed in the Mediterranean resort city of Antalya on Wednesday morning where the Cop31 talks are being presided over by his climate change minister, Chris Bowen, but hosted by Turkey.