The noble gases get their collective moniker from their tendency toward snobbishness. The six elements in the family, which includes helium and neon, don’t normally bond with other elements and they don’t dissolve into minerals the way other gases do. But now, geochemists from Brown University have found a mineral structure with which the nobles deign to fraternize.

Researchers led by Colin Jackson, a graduate student in geological sciences, have found noble gases to be highly soluble in amphibole, a mineral commonly found in oceanic crust. “We found remarkably high solubility,” said Stephen Parman, assistant professor of geological sciences at Brown and Jackson’s Ph.D. adviser. “It was three or four orders of magnitude higher than in any other mineral than had been measured.”

The findings, which are published in Nature Geoscience, are a step toward answering puzzling questions about how noble gases are cycled between the atmosphere and the depths of the Earth.

Completing the cycle

Gases in the air we breathe are on a geological conveyor belt of sorts, cycled from the Earth’s mantle to the atmosphere and back again. Carbon dioxide, water vapor and other gases are released into the atmosphere and oceans from molten magma during volcanic eruptions, and then returned to depths through subduction, when one tectonic plate slides underneath another. The subducting crust is injected deep into the mantle, taking water and any other volatiles it may carry along for the ride.

Noble gases are also released during volcanic activity, but the amount of those gases returned to the mantle through subduction was long thought to be minimal. After all, if noble gases don’t dissolve in minerals, they would lack a vehicle to make the trip. Recent research, however, has suggested that some noble gases are indeed recycled, leaving scientists at a loss to find a mechanism for it. By showing definitively that noble gases are soluble in amphibole, Jackson and his colleagues have shown how noble gases could be carried in subducting slabs.

The key to amphibole’s ability to dissolve noble gases, the researchers say, is its lattice structure. Amphibole and other silicate minerals are made up of tetrahedral and octahedral structures linked together in a way that creates a series of rings. It’s those rings, called A-sites, that provide a home for otherwise finicky noble gases, the research suggests.

Jackson performed a series of experiments to see if the number of empty rings in different types of amphibole were correlated to its ability to dissolve noble gases. He placed cut amphibole gems into a tube with helium or neon under high pressure and temperature, and then used a mass spectrometer to see how much of the gas had dissolved in each gem over the duration of each experiment. The experiments showed that noble gas solubility was highest in types of amphibole with the most unoccupied ring structures.

“This was the meat of the paper,” Parman said. “It’s telling us a specific site where we think the noble gases are. It might be the first time anyone has made a positive identification of where noble gases are going into a mineral.”

Importantly, the researchers said, amphibole isn’t the only crustal mineral with these ring structures. Ring structures are actually quite common in crustal minerals, and could provide a wide variety of potential vehicles that could take noble gases back to the depths via subduction.

A high-fidelity fingerprint

Understanding how noble gases are cycled between the Earth’s surface and interior could shed new light on how other volatiles are recycled, the researchers said.

Scientists are particularly interested in tracking the cycling of water and carbon. Water is obviously vital for life, and carbon cycling has an important impact on the climate. Scientists try to track the cycle by looking at isotope ratios, which can provide a fingerprint that helps to identify where elements originated. Butarbon and the hydrogen in water have only a few isotopes that scientists can use for tracking, and in the case of hydrogen, the isotope ratios are easily thrown off by all kinds of natural processes.

The noble gases, on the other hand, have lots of isotopes, giving scientists ways to track them with great specificity. So if noble gases are cycled in the same minerals that cycle other volatiles like water and carbon, they could be used as a marker to track those other volatiles. “It’s a very high-fidelity fingerprint because you have so many isotopes to play with,” Jackson said.

There’s more work to be done before noble gases could be used as such a fingerprint, but this work does provide a first step: showing which kinds of minerals could be responsible for noble gas recycling.

Other authors on the paper were Simon Kelley of The Open University in the United Kingdom and Reid Cooper, professor of geological sciences at Brown. The work was funded by the National Science Foundation’s Division of Earth Sciences (1019229).

The international study involving experts from the universities of Newcastle, UK, Cologne, Frankfurt and GEOMAR-Kiel, confirms the link between global cooling and a crash in the marine ecosystem during the mid-Cretaceous greenhouse period.

It also quantifies for the first time the amplitude and duration of the temperature change. Analysing the geochemistry and micropaleontology of a marine sediment core taken from the North Atlantic Ocean, the team show that a global temperature drop of up to 5^oC resulted in a major shift in the global carbon cycle over a period of 2.5 million years.

Occurring during a time of high tectonic activity that drove the breaking up of the super-continent Pangaea, the research explains how the opening and widening of new ocean basins around Africa, South America and Europe created additional space where large amounts of atmospheric CO₂ was fixed by photosynthetic organisms like marine algae. The dead organisms were then buried in the sediments on the sea bed, producing organic, carbon rich shale in these new basins, locking away the carbon that was previously in the atmosphere.

The result of this massive carbon fixing mechanism was a drop in the levels of atmospheric CO₂, reducing the greenhouse effect and lowering global temperature.

This period of global cooling came to an end after about 2 million years following the onset of a period of intense local volcanic activity in the Indian Ocean. Producing huge volumes of volcanic gas, carbon that had been removed from the atmosphere when it was locked away in the shale was replaced with CO₂ from Earth’s interior, re-instating a greenhouse effect which led to warmer climate and an end to the “cold snap.”

The research team highlight in this study how global climate is intrinsically linked to processes taking place in Earth’s interior at million year time scales. These processes can modify ecospace for marine life, driving evolution.

Current research efforts tend to concentrate on global warming and the impact that a rise of a few degrees might have on past and present day ecosystems. This study shows that if global temperatures swing the other way by a similar amount, the result can be just as severe, at least for marine life.

However, the research team emphasise that the observed changes of the Earth system in the Cretaceous happened over millions of years, rather than decades or centennial, which cannot easily be related to our rapidly changing modern climate conditions.

“As always it’s a question of fine balance and scale,” explains Thomas Wagner, Professor of Earth Systems Science at Newcastle University, and one of the leaders of this study.

“All earth system processes are operating all the time and at different temporal and spatial scales; but when something upsets the balance — be it a large scale but long term natural phenomenon or a short and massive change to global greenhouse gases due to anthropogenic activity — there are multiple, potential knock-on effects on the whole system.

“The trick is to identify and quantify the initial drivers and consequences, which remains an ongoing challenge in climate research.”

The Government has rejected calls to wind down the coal industry, after a Climate Commission report suggested the majority of the world’s coal must be left unburned.

The report says global carbon dioxide emissions cannot exceed 600 billion tonnes between now and 2050 if the climate is to stay within 2 degrees Celsius of pre-industrial levels.

It says that 600 billion tonne budget is being used far too quickly, and global emissions need to trend downward by the end of the decade to keep temperatures at a manageable level.

Co-author of the report Professor Lesley Hughes says there will be catastrophic consequences for the environment if action is not taken.

“In order to achieve that goal of stabilising the climate at 2 degrees or less, we simply have to leave about 80 per cent of the world’s fossil fuel reserves in the ground,” she said.

“We cannot afford to burn them and still have a stable and safe climate.”

Minister says Australian coal helping millions out of poverty

Federal Resources Minister Gary Gray says he acknowledges the need for clean energy, but says coal is still vital to the global economy.

He says while Australia can turn to natural gas, it should still export its coal reserves.

“There is no solution to global baseload energy generation that does not figure a big contribution by coal,” he said.

“It’s also important for us to have investments in smart coal technologies to ensure that we can capture CO2 in the flue.”

Mr Gray says Australia’s coal is helping nations like India and China bring hundreds of millions of people out of poverty.

“We do have to accept that in a growing region there are still countries that need these resources in order to draw hundreds of millions of people out of poverty,” he said.

“That’s why we also invest in the technologies of the future, not just the minerals processes of the future.”

Coalition says real change depends on global action

Opposition environment spokesman Greg Hunt also ruled out closing the coal industry in a bid to reduce carbon emissions.

Mr Hunt says the Coalition supports Australia’s emissions reduction target, but that real change will not happen until there is a global agreement.

“The key for the world is a global agreement between the big G4 of China and the United States, India and the EU,” he said.

Greens Leader Christine Milne says the Government and the Coalition are showing they do not accept the climate change science.

“You either [accept] climate science and you understand those coal reserves have to stay in the ground or, if you’re going to back those coal reserves and the ports in Queensland, then you don’t believe the climate science,” she said.”

• Lenore Taylor, political editor
• guardian.co.uk, Sunday 16 June 2013 21.58 AEST

Maurice Newman, seen here at the ABC, of which he was formerly chair. He will chair Tony Abbott’s business advisory council Photograph: JEREMY PIPER/AAPIMAGE

The man who will chair Tony Abbott‘s business advisory committee is among a group of country landholders threatening to sue a neighbouring farmer for “substantial damages” if their health or property values are harmed by his agreement to allow wind turbines to built on his property.

Maurice Newman, former chairman of the Australian Stock Exchange and the ABC and chair of Abbott’s three person panel of business advisors, was one of seven families in the Crookwell area who signed a legal letter to local farmer Charlie Prell threatening to sue if the wind farm went ahead and caused them nuisance or harm, including to their health or property values.

The letter urged Prell to seek legal advice as to whether he could break his contract with the wind farm proponent Union Fenosa.

Newman last week described subsidies for renewable energy as “a crime against the people” because higher energy costs hit poorer households the hardest and, in his opinion, the science of global warming was “somewhat in tatters” so there was no longer any logical reason to have them.

The letter, from law firm Piper Alderman on behalf of Newman and the other landholders, states, “Our clients wish to inform you…that they consider that the proposed wind farms, if erected, are likely to constitute a common law nuisance, and therefore an infringement of their rights as neighbouring landowners to have their reasonable enjoyment of their land not disrupted by the wind farm on your land. Our clients also wish you to be in no doubt that they will if necessary take steps to protect their rights, all of which rights are reserved, including to seek compensation for infringement of those rights.”

“…we suggest that, if wind turbines commenced operation on your land, the likely impact on our clients and other neighbours will constitute actionable nuisance for which you will be liable and they would be entitled to recover substantial damages from you.”

The letter says such a lawsuit has not been taken before regarding a wind farm because “of the reluctance of rural people to sue their neighbours, rather than any comment on the law” and warns “please note that our clients are not so reluctant and are ready, willing and able to litigate in order to enforce their proprietary rights to be protected from nuisance caused by you and other hosts.”

The letter also warns Prell that the wind farm operator might not be able to remove the turbines and “remediate’ his property if it suffers financial difficulty “for example because of a change in government energy policy, technical difficulties with the wind farm, or obsolescence.”

Prell says he has no intention of breaking his legal contract with the company, which will help him secure a regular income and “drought proof” his property.

But Prell, who will speak at a pro wind farm rally held in central Canberra on Tuesday, says he is concerned that wind farm projects that could help rural communities like his own might not proceed under a Coalition government.

The Coalition is under intense pressure to back a moratorium on new wind farms and to wind back or scrap the renewable energy target, both from some of it’s own MPs and Senators and from the active anti wind farm lobby that is holding a rally outside Parliament House on Tuesday.

The Coalition has already promised to impose new continuous noise monitoring rules on windfarms that the industry says will inflict crippling costs and provide no useful information but several MPs and Senators are pressing for a moratorium on new wind farms and a scaling back or scrapping of the renewable energy target.

Industry spokesman Ian Macfarlane says the backlash against wind farms is so strong that the new noise policy is the only way to calm “community divisions” .

“If we don’t do this my concern is that the issues around wind farms have the potential to escalate into a community divide similar to coal seam gas,” he told Guardian Australia.

Maurice Newman, chairman of Coalition’s proposed business advisory council, sends legal warning over windfarm