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.

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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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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



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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 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



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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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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.




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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.




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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


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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.

Climate scientists explore hidden ocean beneath Antarctica’s largest ice shelf



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The team used hot-water drilling gear to melt a hole through Antarctica’s Ross Ice Shelf to explore the ocean below.
Christina Hulbe, CC BY-ND

Craig Stevens and Christina Hulbe

Antarctica’s Ross Ice Shelf is the world’s largest floating slab of ice: it’s about the size of Spain, and nearly a kilometre thick.

The ocean beneath, roughly the volume of the North Sea, is one of the most important but least understood parts of the climate system.

We are part of the multi-disciplinary Aotearoa New Zealand Ross Ice Shelf programme team, and have melted a hole through hundreds of metres of ice to explore this ocean and the ice shelf’s vulnerability to climate change. Our measurements show that this hidden ocean is warming and freshening – but in ways we weren’t expecting.

Instruments travelling 360m down a bore hole, from the snow-covered surface of the Ross Ice Shelf through to the ocean below the ice. After splash-down at about 60m, they move through the bubble-rich upper ice and down into the dark bubble-free lower reaches of the ice – passing embedded sediment that left the coast line centuries ago.



Read more:
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A hidden conveyor belt

All major ice shelves are found around the coast of Antarctica. These massive pieces of ice hold back the land-locked ice sheets that, if freed to melt into the ocean, would raise sea levels and change the face of our world.

An ice shelf is a massive lid of ice that forms when glaciers flow off the land and merge as they float out over the coastal ocean. Shelves lose ice by either breaking off icebergs or by melting from below. We can see big icebergs from satellites – it is the melting that is hidden.

Because the water flowing underneath the Ross Ice Shelf is cold (minus 1.9C), it is called a “cold cavity”. If it warms, the future of the shelf and the ice upstream could change dramatically. Yet this hidden ocean is excluded from all present models of future climate.

This satellite map shows the camp site on the Ross Ice Shelf, Antarctica.
Ross Ice Shelf Programme, CC BY-ND

There has only been one set of measurements of this ocean, made by an international team in the late 1970s. The team made repeated attempts, using several types of drills, over the course of five years. With this experience and newer, cleaner, technology, we were able to complete our work in a single season.

Our basic understanding is that seawater circulates through the cavity by flowing in at the sea bed as relatively warm, salty water. It eventually finds its way to the shore – except of course this is a shoreline under as much as 800 metres of ice. There it starts melting the shelf from beneath and flows across the shelf underside back towards the open ocean.

Peering through a hole in the ice

The New Zealand team – including hot water drillers, glaciologists, biologists, seismologists, oceanographers – worked from November through to January, supported by tracked vehicles and, when ever the notorious local weather permitted, Twin Otter aircraft.

As with all polar oceanography, getting to the ocean is often the most difficult part. In this case, we faced the complex task of melting a bore hole, only 25 centimetres in diameter, through hundreds of metres of ice.

A team of ice drillers from Victoria University of Wellington used hot water and a drilling system developed at Victoria to melt a hole through hundreds of metres of ice.
Craig Stevens, CC BY-ND

But once the instruments are lowered more than 300m down the bore hole, it becomes the easiest oceanography in the world. You don’t get seasick and there is little bio-fouling to corrupt measurements. There is, however, plenty of ice that can freeze up your instruments or freeze the hole shut.

A moving world

Our camp in the middle of the ice shelf served as a base for this science, but everything was moving. The ocean is slowly circulating, perhaps renewing every few years. The ice is moving too, at around 1.6 metres each day where we were camped. The whole plate of ice is shifting under its own weight, stretching inexorably toward the ocean fringe of the shelf where it breaks off as sometimes massive icebergs. The floating plate is also bobbing up and down with the daily tides.

The team at work, preparing a mooring.
Christina Hulbe, CC BY-ND

Things also move vertically through the shelf. As the layer stretches toward the front, it thins. But the shelf can also thicken as new snow piles up on top, or as ocean water freezes onto the bottom. Or it might thin where wind scours away surface snow or relatively warm ocean water melts it from below.

When you add it all up, every particle in the shelf is moving. Indeed, our camp was not so far (about 160km) from where Robert Falcon Scott and his two team members were entombed more than a century ago during their return from the South Pole. Their bodies are now making their way down through the ice and out to the coast.

What the future might hold

If the ocean beneath the ice warms, what does this mean for the Ross Ice Shelf, the massive ice sheet that it holds back, and future sea level? We took detailed temperature and salinity data to understand how the ocean circulates within the cavity. We can use this data to test and improve computer simulations and to assess if the underside of the ice is melting or actually refreezing and growing.

Our new data indicate an ocean warming compared to the measurements taken during the 1970s, especially deeper down. As well as this, the ocean has become less salty. Both are in keeping with what we know about the open oceans around Antarctica.

We also discovered that the underside of the ice was rather more complex than we thought. It was covered in ice crystals – something we see in sea ice near ice shelves. But there was not a massive layer of crystals as seen in the smaller, but very thick, Amery Ice Shelf.

Instead the underside of the ice held clear signatures of sediment, likely incorporated into the ice as the glaciers forming the shelf separated from the coast centuries earlier. The ice crystals must be temporary.

None of this is included in present models of the climate system. Neither the effect of the warm, saline water draining into the cavity, nor the very cold surface waters flowing out, the ice crystals affecting heat transfer to the ice, or the ocean mixing at the ice fronts.

The ConversationIt is not clear if these hidden waters play a significant role in how the world’s oceans work, but it is certain that they affect the ice shelf above. The longevity of ice shelves and their buttressing of Antarctica’s massive ice sheets is of paramount concern.

Craig Stevens, Associate Professor in Ocean Physics and Christina Hulbe, Professor and Dean of the School of Surveying (glaciology specialisation)

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