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AEMC suggests new body to decide on battery storage standards
Windlab to receive $10 million milestone success payment in respect of the Coopers Gap Wind Farm
Rethinking the grid: Changes in power sector are an opportunity, not a threat
Brazil opens vast Amazon reserve to mining
Trump thinks clean coal is when workers mine coal and actually ‘clean it’
Home battery market not booming yet – but consumer interest is
WA’s biggest pig farm about to go 100 per cent renewable energy
Will fairy tale Białowieża forest survive Poland’s fight with the EU?
Antarctic ice reveals that fossil fuel extraction leaks more methane than thought
![](https://cdn.theconversation.com/files/183132/width496/file-20170823-13299-1u60k1n.jpg)
The fossil fuel industry is a larger contributor to atmospheric methane levels than previously thought, according to our research which shows that natural seepage of this potent greenhouse gas from oil and gas reservoirs is more modest than had been assumed.
In our research, published in Nature today, our international team studied Antarctic ice dating back to the last time the planet warmed rapidly, roughly 11,000 years ago.
Katja Riedel and Hinrich Schaefer discuss NIWA’s ice coring work at Taylor Glacier in Antarctica.We found that natural seepage of methane from oil and gas fields is much lower than anticipated, implying that leakage caused by fossil fuel extraction has a larger role in today’s emissions of this greenhouse gas.
However, we also found that vast stores of methane in permafrost and undersea gas hydrates did not release large amounts of their contents during the rapid warming at the end of the most recent ice age, relieving fears of a catastrophic methane release in response to the current warming.
The ice is processed in a large melter before samples are shipped back to New Zealand.
Hinrich Schaefer, CC BY-ND
Methane levels started to increase with the industrial revolution and are now 2.5 times higher than they ever were naturally. They have caused one-third of the observed increase in global average temperatures relative to pre-industrial times.
If we are to reduce methane emissions, we need to understand where it comes from. Quantifying different sources is notoriously tricky, but it is especially hard when natural and human-driven emissions happen at the same time, through similar processes.
Read more: Detecting methane leaks with infrared cameras: they’re fast, but are they effective
The most important of these cases is natural methane seepage from oil and gas fields, also known as geologic emissions, which often occurs alongside leakage from production wells and pipelines.
The total is reasonably well known, but where is the split between natural and industrial?
To make matters worse, human-caused climate change could destabilise permafrost or ice-like sediments called gas hydrates (or clathrates), both of which have the potential to release more methane than any human activity and reinforce climate change. This scenario has been hypothesised for past warming events (the “clathrate gun”) and for future runaway climate change (the so-called “Arctic methane bomb”). But how likely are these events?
![](https://cdn.theconversation.com/files/183134/width754/file-20170823-13285-16053hy.jpg)
To find answers, we needed a time capsule. This is provided by tiny air bubbles enclosed in polar ice, which preserve ancient atmospheres. By using radiocarbon (14C) dating to determine the age of methane from the end of the last ice age, we can work out how much methane comes from contemporary processes, like wetland production, and how much is from previously stored methane. During the time the methane is stored in permafrost, sediments or gas fields, the 14C decays away so that these sources emit methane that is radiocarbon-free.
In the absence of strong environmental change and industrial fossil fuel production, all radiocarbon-free methane in samples from, say, 12,000 years ago will be from geologic emissions. From that baseline, we can then see if additional radiocarbon-free methane is released from permafrost or hydrates during rapid warming, which occurred around 11,500 years ago while methane levels shot up.
Tracking methane in iceThe problem is that there is not much air in an ice sample, very little methane in that air, and a tiny fraction of that methane contains a radiocarbon (14C) atom. There is no hope of doing the measurements on traditional ice cores.
Our team therefore went to Taylor Glacier, in the Dry Valleys of Antarctica. Here, topography, glacier flow and wind force ancient ice layers to the surface. This provides virtually unlimited sample material that spans the end of the last ice age.
![](https://cdn.theconversation.com/files/183136/width754/file-20170823-13285-gv9u10.jpg)
For a single measurement, we drilled a tonne of ice (equivalent to a cube with one-metre sides) and melted it in the field to liberate the enclosed air. From the gas-tight melter, the air was transferred to vacuum flasks and shipped to New Zealand. In the laboratory, we extracted the pure methane out of these 100-litre air samples, to obtain a volume the size of a water drop.
Only every trillionth of the methane molecules contains a 14C atom. Our collaborators in Australia were able to measure exactly how big that minute fraction is in each sample and if it changed during the studied period.
Low seepage, no gun, no bombBecause radiocarbon decays at a known rate, the amount of 14C gives a radiocarbon age. In all our samples the radiocarbon date was consistent with the sample age.
Radiocarbon-free methane emissions did not increase the radiocarbon age. They must have been very low in pre-industrial times, even during a rapid warming event. The latter indicates that there was no clathrate gun or Arctic methane bomb going off.
So, while today’s conditions differ from the ice-covered world 12,000 years ago, our findings implicate that permafrost and gas hydrates are not too likely to release large amounts of methane in future warming. That is good news.
Wetlands must have been responsible for the increase in methane at the end of the ice age. They have a lesser capacity for emissions than the immense permafrost and clathrate stores.
Geologic emissions are likely to be lower today than in the ice age, partly because we have since drained shallow gas fields that are most prone to natural seepage. Yet, our highest estimates are only about half of the lower margin estimated for today. The total assessment (natural plus industrial) for fossil-fuel methane emissions has recently been increased.
In addition, we now find that a larger part of that must come from industrial activities, raising the latter to one third of all methane sources globally. For comparison, the last IPCC report put them at 17%.
Measurements in modern air suggest that the rise in methane levels over the last years is dominated by agricultural emissions, which must therefore be mitigated. Our new research shows that the impact of fossil fuel use on the historic methane rise is larger than assumed. In order to mitigate climate change, methane emissions from oil, gas and coal production must be cut sharply.
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Hinrich Schaefer works for the National Institute of Water and Atmospheric Research. He has received funding from the New Zealand Government through Strategic Science Investment Funds and a Marsden Grant. In previous positions, his work has received government funding from Germany, the European Union, Canada and the USA, as well as a grant from the American Chemical Society.
Capturing the true wealth of Australia’s waste
![](https://cdn.theconversation.com/files/183101/width496/file-20170823-13308-ce4edu.jpg)
One of the byproducts of landfill is “landfill gas”, a mixture of mostly methane and carbon dioxide generated by decomposing organic material. Methane is a particularly potent greenhouse gas, but it can be captured from landfill and used to generate clean electricity.
Methane capture is a valuable source of power but, more importantly, it can significantly reduce Australia’s methane emissions. However the opportunity to produce energy from waste is largely being squandered, as up to 80% of the potential methane in waste is not used.
If more councils were prepared to invest in better facilities, Australians would benefit from less waste in landfill and more energy in our grids. Even the by-product from using state-of-art processing methods can be used as a bio-fertiliser.
Read more: Explainer: how much landfill does Australia have?
And while these facilities are initially more expensive, Australians are generally very willing to recycle, compost and take advantage of community schemes to reduce waste. It’s reasonable to assume that a considerable percentage of our population would support updating landfill plants to reduce methane emissions.
Recycling in AustraliaAustralia may have a bad rap when it comes to waste recycling, but there are plenty of positives.
Australians produce approximately 600 kilograms of domestic waste per person, per year – no more than most northern European countries, which set the benchmark in sustainable waste management.
Looking at kerbside bins we, on average, recycle 30-35% of that waste, saving much of our paper, glass, aluminium and steel from landfill (which also saves and reduces emissions).
Although the household recycling rate in Australia is less than the best-performing EU recycling rates of 40-45%, this is primarily due to a lack of access to (or awareness of) schemes to recycle e-waste and metals. Data therefore suggests that at the community level, there is a willingness to minimise and recycle waste.
Read more:
Australia is still miles behind in recycling electronic products
Campaigns urging us to ‘care more’ about food waste miss the point
Between 55% and 60% of kerbside waste sent to landfill in Australia is organic material. Over 65% of this organic fraction is food waste, similar to the make-up of the EU organic waste stream, comprised of 68% of food waste.
Despite this large fraction, approximately half of the household organic we produce – mostly garden waste – is separately collected and disposed, again demonstrating high participation by the community in recycling when collection and disposal options are available.
Turning waste into energyEnergy recovery from waste is the conversion of non-recyclable material into useable heat, electricity, or fuel. Solid, non-organic waste is usually converted to energy after being heated, but organic waste like kitchen and and garden refuse has too much moisture to be treated this way.
Read more: Explainer: why we should be turning waste into fuel
Instead, when organic waste is sent to landfill it is broken down naturally by microorganisms. This process releases methane, a greenhouse gas 25 times more potent than carbon dioxide, and represents the loss of a valuable energy resource.
Around 130 landfills in Australia are capturing methane and using it to generate electricity. Based on installed power generation capacity and the amount of waste received, Australia’s largest landfills use 20-30% of the potential methane in waste for electricity generation.
Ravenhall in Melbourne processes 1.4 million tonnes of waste per year, and proposes to generate 8.8 megawatts (MW) of electricity by 2020. Roughly 461,000 tonnes of waste goes to Woodlawn in NSW, and in 2011 it generated 4MW of electrical power. Swanbank in Queensland receives 500,000 tonnes a year and generates 1.1MW.
The remainder of the methane is flared due to poor gas quality or insufficient transmission infrastructure, is oxidised as it migrates towards the surface of the landfill, or simply escapes. The methane generating capacity of waste is also diminished because organics begin composting as soon as they reach landfill.
But there are more efficient ways to capture methane using specialised anaerobic digestion tanks. The process is simple: an anaerobic (oxygen free) tank is filled with organic waste, which is broken down by bacteria to produce biogas. This is similar to the natural process that occurs in landfill, but is much more controlled and efficient in a tank.
Read more: Biogas: smells like a solution to our energy and waste problems
The biogas can be combusted to produce electricity and heat, or can be converted to pure biomethane to be used either in the mains gas grid, or as a renewable transport fuel. In contrast to landfills, 60-80% of the methane potential of waste is used to generate electricity in anaerobic digesters, with most of the remainder used to power waste handling and the digestion process.
The nutrient-rich sludge that remains after anaerobic digestion, called digsetate, is also a valuable biofertiliser. It can support food production, and further reduce greenhouse gases by decreasing our reliance on energy-intensive manufactured fertilisers.
The use of food waste as a feedstock for anaerobic digestion is largely untapped in Australia but has huge potential. A site in Sydney’s geographic centre (Earth Power Technologies) and Richgro’s Jandakot facility near Perth are part of a handful that are converting food waste to energy using this technology.
The future of organic recyclingLocal council recycling and waste infrastructure is typically not a priority election issue, except for those close to existing or proposed landfills.
Read more: Australian recycling plants have no incentive to improve
Ratepayers are generally not informed of the possibility of separately collecting food waste, either for industrial-scale composting or methane capture. We have the right to this information, with costs and benefits presented in the context of the costs we already pay for waste management, and relative to the environmental performance of landfill.
As an example, landfill operators often promote the number of homes they power by electricity generated from methane as a key measure of sustainability. But how does this compare to the electricity and heat that might be obtained from an anaerobic digester that processes the same waste?
Given the choice, the Australian community may have an appetite to extend organic recycling beyond well-established garden waste composting. They only have to be asked.
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William Clarke has received funding from the Australian Research Council, the Queensland Government and Remondis Australia. He is a member of the Managing Board of the International Waste Working Group.
Bernadette McCabe is a member of Bioenergy Australia and is National Team Leader for the International Energy Agency Task 37 Energy from Biogas
Coal in decline: an energy industry on life support
Special report: The pace of coal plants shutting down in Australia could mean the country’s fleet could be gone before 2040. The transformation is enormous – and seems inevitable
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For a glimpse into the future of coal power in Australia, go west. The country’s last major investment in coal-fired electricity was in Western Australia in 2009, when Colin Barnett’s state government announced a major refurbishment of the Muja AB station about 200km south of Perth, far from the gaze of the east coast political-media class.
The plant was 43 years old and mothballed. Reviving it was meant to cost $150m, paid for by private investors who would reap the benefits for years to come. But costs and timeframes blew out. An old corroded boiler exploded. The joint venture financing the project collapsed; a wall followed suit. The bill ultimately pushed beyond $300m, much of it to be stumped up by taxpayers – and once completed, the plant was beset with operational problems. It ran only 20% of the time.
Continue reading...'Alarmingly high' levels of arsenic in Pakistan's ground water
Have you modified your bicycle? Share your photos with us
Bicycles offer endless opportunities for modification, both practical and decorative. We’d like you to share your bicycle projects with us
From converting a multi-speed hub into a fixed gear, adding downtube shift levers or simply a comfy seat, a bicycle offers endless opportunities for the DIY enthusiast. We’d like you to share your bicycle modifications with us.
Whether it’s to help those with mobility problems, to transport your children or just to look like the coolest rider on the street, there are any number of ways to make your bike even better.
Continue reading...Tributes paid to 'silent hero' wildlife conservationist killed in Tanzania
Government officials and fellow conservationists paid tribute to Wayne Lotter at a special memorial yesterday
Hundreds of people gathered at Baobab Village in Dar es Salaam to pay tribute to Wayne Lotter on Tuesday evening, as tributes continued to come in from around the world.
Lotter, 51, was shot and killed last week while travelling in a taxi from the airport to his hotel on Dar es Salaam’s Msasani Peninsula. Lotter, who co-founded PAMS Foundation, a conservation nonprofit, was responsible for supporting anti-poaching efforts that had led to the arrests of more than 2000 ivory poachers and traffickers, and had taken down several key poaching syndicates in the country. He had received numerous death threats since starting the organization in 2009.
Continue reading...Invasive rhododendrons damage woodland environment
Motorist would not have landed cyclist's 'wanton and furious driving' charge
Charlie Alliston should have had a front brake but 18mph is a cautious speed and double standards are at work here
A heavy-handed prosecution against a cyclist for manslaughter has failed but a charge of “wanton and furious driving” has succeeded.
In 2016 more than 400 pedestrians were killed on UK roads. Each a terrible tragedy to those involved and almost all avoidable. One of these casualties, Kim Briggs, died after a collision between herself and a teenage cyclist, Charlie Alliston.
Continue reading...Arctic radar to probe 'space weather'
Conservationists slam 'hateful' survey promoting wasp killing
Big Wasp Survey encourages volunteers to build homemade traps then send dead wasps to entomologists to monitor populations
Drowning wasps in beer in the name of science may seem a socially acceptable way to exterminate a seasonal pest. But a citizen science survey “harnessing the public’s dislike of wasps” has been criticised for its “hateful language” and for unnecessarily killing rare insects.
The Big Wasp Survey is encouraging 2,000 volunteers to build homemade bottle traps before posting the dead wasps to entomologists to produce a clearer picture of the much-maligned insect’s decline.
Continue reading...Three more rangers killed in a deadly month around the world for wildlife defenders
Wildlife protection has become an increasingly dangerous business as rangers face armed gunmen and poachers
Three rangers have been killed in separate countries in a deadly month for wildlife defenders.
A ranger at Serra da Capivara national park, in Brazil’s north-eastern Piaui region, was killed by hunters on 18 August. Edilson Aparecido da Costa Silva and two other colleagues were patrolling the park when they were ambushed by a group of four armed men who are believed to have been hunting in the park illegally. Costa Silva was killed in the shootout that followed, while the other two rangers were injured.
Continue reading...Firefighters eat sausages made of piglets they saved from blaze
Farmer sends gift of sausages to thank Wiltshire firefighters who rescued piglets and two sows from fire in barn
A farmer whose piglets were saved from a barn fire has served the animals up as sausages to thank the firefighters who rescued them.
The baby pigs and two sows were freed by firefighters from Pewsey in Wiltshire when a barn went up in flames in February.
Continue reading...