Expanding gas mining threatens our climate, water and health


Melissa Haswell, Queensland University of Technology and David Shearman, University of Adelaide

Australia, like its competitors Qatar, Canada and the United States, aspires to become the world’s largest exporter of gas, arguing this helps importing nations reduce their greenhouse emissions by replacing coal.

Yes, burning gas emits less carbon dioxide than burning coal. Yet the “fugitive emissions” – the methane that escapes, often unmeasured, during production, distribution and combustion of gas – is a much more potent short-term greenhouse gas than carbon dioxide.




Read more:
Who gets to decide whether we dig up coal and gas?


A special report issued by the World Health Organisation after the 2018 Katowice climate summit urged governments to take “specific commitments to reduce emissions of short-lived climate pollutants” such as methane, so as to boost the chances of staying with the Paris Agreement’s ambitious 1.5℃ global warming limit.

Current gas expansion plans in Western Australia, the Northern Territory and Queensland, where another 2,500 coal seam gas wells have been approved, reveal little impetus to deliver on this. Harvesting all of WA’s gas reserves would emit about 4.4 times more carbon dioxide equivalent than Australia’s total domestic energy-related emissions budget.

Gas as a cause of local ill-health

There are not only global, but also significant local and regional risks to health and well-being associated with unconventional gas mining. Our comprehensive review examines the current state of the evidence.

Since our previous reviews (see here, here and here), more than 1,400 further peer-reviewed articles have been published, helping to clarify how expanding unconventional gas production across Australia risks our health, well-being, climate, water and food security.




Read more:
Chief Scientist CSG report leaves health concerns unanswered


This research has been possible because, since 2010, 17.6 million US citizens’ homes have been within a mile (1.6km) of gas wells and fracking operations. Furthermore, some US research funding is independent of the gas industry, whereas much of Australia’s comparatively small budget for research in this area is channelled through an industry-funded CSIRO research hub.

Key medical findings

There is evidence that living close to unconventional gas mining activities is linked to a wide range of health conditions, including psychological and social problems.

The US literature now consistently reports higher frequencies of low birth weight, extreme premature births, higher-risk pregnancies and some birth defects, in pregnancies spent closer to unconventional gas mining activities, compared with pregnancies further away. No parallel studies have so far been published in Australia.

US studies have found increased indicators of cardiovascular disease, higher rates of sinus disorders, fatigue and migraines, and hospitalisations for asthma, heart, neurological, kidney and urinary tract conditions, and childhood blood cancer near shale gas operations.

Exploratory studies in Queensland found higher rates of hospitalisation for circulatory, immune system and respiratory disorders in children and adults in the Darling Downs region where coal seam gas mining is concentrated.

Water exposure

Chemicals found in gas mining wastewater include volatile organic compounds such as benzene, phenols and polyaromatic hydrocarbons, as well as heavy metals, radioactive materials, and endocrine-disrupting substances – compounds that can affect the body’s hormones.

This wastewater can find its way into aquifers and surface water through spillage, injection procedures, and leakage from wastewater ponds.

The environmental safety of treated wastewater and the vast quantities of crystalline salt produced is unclear, raising questions about cumulative long-term impacts on soil productivity and drinking water security.

Concern about the unconventional gas industry’s use of large quantities of water has increased since 2013. Particularly relevant to Australian agriculture and remote communities is research showing an unexpected but consistent increase in the “water footprint” of gas wells across all six major shale oil and gas mining regions of the US from 2011 to 2016. Maximum increases in water use per well (7.7-fold higher, Permian deposits, New Mexico and Texas) and wastewater production per well (14-fold, Eagle Ford deposits, Texas) occurred where water stress is very high. The drop in water efficiency was tied to a drop in gas prices.

Air exposure

Research on the potentially harmful substances emitted into the atmosphere during water removal, gas production and processing, wastewater handling and transport has expanded. These substances include fine particulate pollutants, ground-level ozone, volatile organic compounds, polycyclic aromatic hydrocarbons, hydrogen sulfide, formaldehyde, diesel exhaust and endocrine-disrupting chemicals.

Measuring concentrations and human exposures to these pollutants is complicated, as they vary widely and unpredictably in both time and location. This makes it difficult to prove a definitive causal link to human health impacts, despite the mounting circumstantial evidence.




Read more:
Why Australians need a national environment protection agency to safeguard their health


Our review found substantially more evidence of what we suspected in 2013: that gas mining poses significant threats to the global climate, to food and water supplies, and to health and well-being.

On this basis, Doctors for the Environment Australia (DEA) has reinforced its position that no new gas developments should occur in Australia, and that governments should increase monitoring, regulation and management of existing wells and gas production and transport infrastructure.The Conversation

Melissa Haswell, Professor of Health, Safety and Environment, School of Public Health and Social Work, Queensland University of Technology, Queensland University of Technology and David Shearman, Emeritus Professor of Medicine, University of Adelaide

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

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Here’s how a 100% renewable energy future can create jobs and even save the gas industry



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The gas industry of the future could manufacture and deliver renewable fuels, rather than mining and processing natural gas.
Shutterstock.com

Sven Teske, University of Technology Sydney

The world can limit global warming to 1.5℃ and move to 100% renewable energy while still preserving a role for the gas industry, and without relying on technological fixes such as carbon capture and storage, according to our new analysis.

The One Earth Climate Model – a collaboration between researchers at the University of Technology Sydney, the German Aerospace Center and the University of Melbourne, and financed by the Leonardo DiCaprio Foundation – sets out how the global energy supply can move to 100% renewable energy by 2050, while creating jobs along the way.

It also envisions how the gas industry can fulfil its role as a “transition fuel” in the energy transition without its infrastructure becoming obsolete once natural gas is phased out.




Read more:
Want to boost the domestic gas industry? Put a price on carbon


Our scenario, which will be published in detail as an open access book in February 2019, sets out how the world’s energy can go fully renewable by:

  • increasing electrification in the heating and transport sector

  • significant increase in “energy productivity” – the amount of economic output per unit of energy use

  • the phase-out of all fossil fuels, and the conversion of the gas industry to synthetic fuels and hydrogen over the coming decades.

Our model also explains how to deliver the “negative emissions” necessary to stay within the world’s carbon budget, without relying on unproven technology such as carbon capture and storage.

If the renewable energy transition is accompanied by a worldwide moratorium on deforestation and a major land restoration effort, we can remove the equiavalent of 159 billion tonnes of carbon dioxide from the atmosphere (2015-2100).

Combining models

We compiled our scenario by combining various computer models. We used three climate models to calculate the impacts of specific greenhouse gas emission pathways. We then used another model to analyse the potential contributions of solar and wind energy – including factoring in the space constraints for their installation.

We also used a long-term energy model to calculate future energy demand, broken down by sector (power, heat, industry, transport) for 10 world regions in five-year steps. We then further divided these 10 world regions into 72 subregions, and simulated their electricity systems on an hourly basis. This allowed us to determine the precise requirements in terms of grid infrastructure and energy demand.

Interactions between the models used for the One Earth Model.
One Earth Model, Author provided

‘Recycling’ the gas industry

Unlike many other 1.5℃ and/or 100% renewable energy scenarios, our analysis deliberately integrates the existing infrastructure of the global gas industry, rather than requiring that these expensive investments be phased out in a relatively short time.

Natural gas will be increasingly replaced by hydrogen and/or renewable methane produced by solar power and wind turbines. While most scenarios rely on batteries and pumped hydro as main storage technologies, these renewable forms of gas can also play a significant role in the energy mix.

In our scenario, the conversion of gas infrastructure from natural gas to hydrogen and synthetic fuels will start slowly between 2020 and 2030, with the conversion of power plants with annual capacities of around 2 gigawatts. However, after 2030, this transition will accelerate significantly, with the conversion of a total of 197GW gas power plants and gas co-generation facilities each year.

Along the way the gas industry will have to redefine its business model from a supply-driven mining industry, to a synthetic gas or hydrogen fuel production industry that provides renewable fuels for the electricity, industry and transport sectors. In the electricity sector, these fuels can be used to help smooth out supply and demand in networks with significant amounts of variable renewable generation.

A just transition for the fossil fuel industry

The implementation of the 1.5℃ scenario will have a significant impact on the global fossil fuel industry. While this may seem to be stating the obvious, there has so far been little rational and open debate about how to make an orderly withdrawal from the coal, oil, and gas extraction industries. Instead, the political debate has been focused on prices and security of supply. Yet limiting climate change is only possible when fossil fuels are phased out.

Under our scenario, gas production will only decrease by 0.2% per year until 2025, and thereafter by an average of 4% a year until 2040. This represents a rather slow phase-out, and will allow the gas industry to transfer gradually to hydrogen.

Our scenario will generate more energy-sector jobs in the world as a whole. By 2050 there would be 46.3 million jobs in the global energy sector – 16.4 million more than under existing forecasts.




Read more:
The government is right to fund energy storage: a 100% renewable grid is within reach


Our analysis also investigated the specific occupations that will be required for a renewables-based energy industry. The global number of jobs would increase across all of these occupations between 2015 and 2025, with the exception of metal trades which would decline by 2%, as shown below.

Division of occupations between fossil fuel and renewable energy industries in 2015 and 2025.
One Earth Model, Author provided

However, these results are not uniform across regions. China and India, for example, will both experience a reduction in the number of jobs for managers and clerical and administrative workers between 2015 and 2025.

Our analysis shows how the various technical and economic barriers to implementing the Paris Agreement can be overcome. The remaining hurdles are purely political.The Conversation

Sven Teske, Research Director, Institute for Sustainable Futures, University of Technology Sydney

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

How biomethane can help turn gas into a renewable energy source



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Are there greener pastures ahead for gas?
Shutterstock.com

Bernadette McCabe, University of Southern Queensland

Australia’s report card on reducing its greenhouse gas emissions is not exactly glowing, but there are ample opportunities to get it on track during this period of rapid change in the energy sector. Greater use of renewable electricity sources like wind and solar are playing a large part in reducing emissions, and gas can also lift its game.

Gas provides nearly one quarter of Australia’s total energy supply. Around 130,000 commercial businesses rely on gas, and it delivers 44% of Australia’s household energy to more than 6.5 million homes which use natural gas for hot water, domestic heating, or cooking.

Gas has lower greenhouse emissions than most other fuels, and the gas used in power generation has about half the emissions of the current electricity grid.

Even so, natural gas can do more to help Australia meet its carbon-reduction targets.




Read more:
Biogas: smells like a solution to our energy and waste problems


An industry document released last year, Gas Vision 2050, explains how new technologies such as biomethane and hydrogen can make that happen, by replacing conventional natural gas with low-emission alternative fuels.

Around the world

Worldwide, renewable natural gas is dominated by biomethane, which can be generated from organic materials and residues from agriculture, food production and waste processing.

Multiple products of anaerobic digestion.
Modified from ADBA with permission

The top biomethane-producing countries include Germany, the UK, Sweden, France and the United States, and many others are planning to use renewable gas more widely.

A 2017 report suggests that renewable natural gas could meet 76% of Europe’s natural gas demand by 2050.

What is biomethane?

Biomethane is a clean form of biogas that is 98% methane. Also known as green gas, it can be used interchangeably with conventional fossil-fuel natural gas.

Biogas is a mixture of around 60% methane and 40% carbon dioxide, plus traces of other contaminants. Turning biogas into biomethane requires technology that scrubs out the carbon dioxide.

Biomethane’s benefits include:

  • Net zero emissions
  • Interchangeability with existing natural gas usage
  • Ability to capture methane emissions from other processes such as landfill and manure production
  • Potential economic opportunity for regional areas
  • Generation of skilled jobs in planning, engineering, operating and maintenance of biogas and biomethane plants.

Australia’s potential for biomethane

While Australia currently does not have any upgrading plants, the production of biomethane can provide a huge boost to Australia’s nascent biogas industry.

The main use for biogas in Australia is for electricity production, heat, and combined heat and power.

Australia’s biogas sector has more than 240 anaerobic digestion (AD) plants, most of which are associated with landfill gas power units and municipal wastewater treatment. They also include:

  • about 20 agricultural AD plants, which use waste manure from piggeries
  • about 18 industrial AD plants, which use wastewater from red meat processing and rendering as feedstock for biogas production;

There is also manure from around one million head of cattle in feedlots, which is currently not used to produce biogas, but is stockpiled for use as fertiliser on agricultural land.

Australian biogas facilities.
CAE/USQ

There are untapped opportunities to produce biomethane using municipal sewage sludge, red meat processing waste, residues from breweries and distilleries, food waste, and poultry and cattle manure.




Read more:
Home biogas: turning food waste into renewable energy


The Australian Renewable Energy Agency is currently supporting the Australian Biomass for Bioenergy (ABBA) project. The Australian Renewable Energy Mapping Infrastructure (AREMI) platform will map existing and projected biomass resource data from the ABBA project, alongside other parameters such as existing network and transport infrastructure, land-use capability, and demographic data.

This topic and many others related to biogas and bioenergy more widely will be discussed at this week’s Annual Bioenergy Australia conference.

Of course, biomethane is just one way in which Australia can make the transition to a low-emissions future. But as natural gas is already touted as a “transition fuel” to a low-carbon economy, these new technologies can help ensure that existing gas infrastructure can still be used in the future.The Conversation

Bernadette McCabe, Associate Professor and Principal Scientist, University of Southern Queensland

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

New Zealand puts an end to new permits for exploration of deep-sea oil and gas reserves



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New Zealand’s government will not grant any new permits for exploration of offshore oil and gas reserves.
from http://www.shutterstock.com, CC BY-SA

James Renwick, Victoria University of Wellington

The New Zealand government’s announcement that it will not issue any new permits for offshore exploration for oil and gas deposits is exciting, and a step in the right direction.

We know that we can’t afford to burn much more oil if we want to meet the Paris Agreement target of keeping global temperature rise this century well below two degrees above pre-industrial levels. Almost all of the already known reserves must stay in the ground, and there is no room to go exploring for more.

Pursuing further reserves would only lead to stranded assets and would waste time and resources in the short term.




Read more:
Why New Zealand should not explore for more natural gas reserves


Moving away from fossil fuels

New Zealand currently has 31 active permits for oil and gas exploration, and 22 of these are offshore. A program set up by the previous government invites bids each year for new onshore and offshore exploration permits. But this year it is restricted to the onshore Taranaki Basin, on the west coast of the North Island.

Complementing the move to shut down the exploration of new deep-sea fossil fuel reserves, the government’s new transport funding plan aims to reduce demand for fossil fuels by putting emphasis on public transport, cycling and walking.

This gets away from the outdated mantra of more roads and more cars that we have seen over the past decade and will tackle the transport sector, which has seen very rapid growth in emissions since 1990. This will help New Zealand onto a low-carbon pathway and promises a more people-focused future.

New Zealand is a small player in global emissions of greenhouse gases but our actions can carry symbolic weight on the world stage. Given our present position of 80% renewable electricity and an abundance of solar, wind, wave and tidal energy, if any country can become zero-carbon, surely New Zealand can. It can only benefit New Zealand – socially, economically and politically – to lead in this crucial race to stabilise the climate.




Read more:
A new approach to emissions trading in a post-Paris climate


Rising emissions

As the government announced its ban on new offshore exploration permits, the latest greenhouse gas inventory was also released, showing some good news. New Zealand’s gross emissions went down slightly from 2015 to 2016.

But gross emissions are up nearly 20% since 1990, and net emissions (actual emissions minus the “sinks” from forestry) are up 54% over that time. The main factors that contributed to the increase were dairy intensification and increased transport and energy emissions.

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Even though agriculture is still the largest source of emissions overall, energy and transport are close behind. We have seen a near-doubling in carbon dioxide emissions from road transport over the past 27 years.

It is encouraging to see a decrease in emissions from the waste sector. Per head of population, New Zealanders throw away significantly above the OECD average of rubbish, a lot of which is green waste that decomposes and releases methane, another potent but short-lived greenhouse gas.

https://datawrapper.dwcdn.net/1hCga/1/

While New Zealand emits a tiny fraction of the world’s greenhouse gases, on a per-capita basis we are sixth-highest among developed countries. We have as much responsibility as any country to reduce our emissions.

Even though emissions have risen, we are set to meet our national target for 2020 (a 5% reduction on 1990 levels) because of “carry-over” credits from the first Kyoto reporting period from 2008 to 2012. But to live up to more stringent future targets, we need a lot more action than we’ve seen over the last decade. The government plans to introduce zero-carbon legislation that will commit New Zealand to reaching the goal of carbn neutrality by 2050.

The ConversationThis will require serious investment and commitment to renewable technologies, changes in the transport sector, changes to agriculture and land use, and ultimately changes in the way we all live our lives.

James Renwick, Professor, Physical Geography (climate science), Victoria University of Wellington

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

Fossil fuel emissions hit record high after unexpected growth: Global Carbon Budget 2017


Pep Canadell, CSIRO; Corinne Le Quéré, University of East Anglia; Glen Peters, Center for International Climate and Environment Research – Oslo; Robbie Andrew, Center for International Climate and Environment Research – Oslo; Rob Jackson, Stanford University, and Vanessa Haverd, CSIRO

Global greenhouse emissions from fossil fuels and industry are on track to grow by 2% in 2017, reaching a new record high of 37 billion tonnes of carbon dioxide, according to the 2017 Global Carbon Budget, released today.

The rise follows a remarkable three-year period during which global CO₂ emissions barely grew, despite strong global economic growth.

But this year’s figures suggest that the keenly anticipated global peak in emissions – after which greenhouse emissions would ultimately begin to decline – has yet to arrive.


Read more: Fossil fuel emissions have stalled: Global Carbon Budget 2016


The Global Carbon Budget, now in its 12th year, brings together scientists and climate data from around the world to develop the most complete picture available of global greenhouse gas emissions.

In a series of three papers, the Global Carbon Project’s 2017 report card assesses changes in Earth’s sources and sinks of CO₂, both natural and human-induced. All excess CO₂ remaining in the atmosphere leads to global warming.

We believe society is unlikely to return to the high emissions growth rates of recent decades, given continued improvements in energy efficiency and rapid growth in low-carbon energies. Nevertheless, our results are a reminder that there is no room for complacency if we are to meet the goals of the Paris Agreement, which calls for temperatures to be stabilised at “well below 2℃ above pre-industrial levels”. This requires net zero global emissions soon after 2050.

After a brief plateau, 2017’s emissions are forecast to hit a new high.
Global Carbon Project, Author provided

National trends

The most significant factor in the resumption of global emissions growth is the projected 3.5% increase in China’s emissions. This is the result of higher energy demand, particularly from the industrial sector, along with a decline in hydro power use because of below-average rainfall. China’s coal consumption grew by 3%, while oil (5%) and gas (12%) continued rising. The 2017 growth may result from economic stimulus from the Chinese government, and may not continue in the years ahead.

The United States and Europe, the second and third top emitters, continued their decade-long decline in emissions, but at a reduced pace in 2017.

For the US, the slowdown comes from a decline in the use of natural gas because of higher prices, with the loss of its market share taken by renewables and to a lesser extent coal. Importantly, 2017 will be the first time in five years that US coal consumption is projected to rise slightly (by about 0.5%).

The EU has now had three years (including 2017) with little or no decline in emissions, as declines in coal consumption have been offset by growth in oil and gas.

Unexpectedly, India’s CO₂ emissions will grow only about 2% this year, compared with an average 6% per year over the past decade. This reduced growth rate is likely to be short-lived, as it was linked to reduced exports, lower consumer demand, and a temporary fall in currency circulation attributable to demonetisation late in 2016.

Trends for the biggest emitters, and everyone else.
Global Carbon Project, Author provided

Yet despite this year’s uptick, economies are now decarbonising with a momentum that was difficult to imagine just a decade ago. There are now 22 countries, for example, for which CO₂ emissions have declined over the past decade while their economies have continued to grow.

Concerns have been raised in the past about countries simply moving their emissions outside their borders. But since 2007, the total emissions outsourced by countries with emissions targets under the Kyoto Protocol (that is, developed countries, including the US) has declined.

This suggests that the downward trends in emissions of the past decade are driven by real changes to economies and energy systems, and not just to offshoring emissions.

Other countries, such as Russia, Mexico, Japan, and Australia have shown more recent signs of slowdowns, flat growth, and somewhat volatile emissions trajectories as they pursue a range of different climate and energy policies in recent years.

Still, the pressure is on. In 101 countries, representing 50% of global CO₂ emissions, emissions increased as economies grew. Many of these countries will be pursuing economic development for years to come.

Contrasting fortunes among some of the world’s biggest economies.
Nigel Hawtin/Future Earth Media Lab/Global Carbon Project, Author provided

A peek into the future

During the three-year emissions “plateau” – and specifically in 2015-16 – the accumulation of CO₂ in the atmosphere grew at a record high that had not previously been observed in the half-century for which measurements exist.

It is well known that during El Niño years such as 2015-16, when global temperatures are higher, the capacity of terrestrial ecosystems to take up CO₂ (the “land sink”) diminishes, and atmospheric CO₂ growth increases as a result.

The El Niño boosted temperatures by roughly a further 0.2℃. Combined with record high levels of fossil fuel emissions, the atmospheric CO₂ concentration grew at a record rate of nearly 3 parts per million per year.

This event illustrates the sensitivity of natural systems to global warming. Although a hot El Niño might not be the same as a sustained warmer climate, it nevertheless serves as a warning of the global warming in store, and underscores the importance of continuing to monitor changes in the Earth system.

The effect of the strong 2015-16 El Niño on the growth of atmospheric CO₂ can clearly be seen.
Nigel Hawtin/Future Earth Media Lab/Global Carbon Project, based on Peters et al., Nature Climate Change 2017, Author provided

No room for complacency

There is no doubt that progress has been made in decoupling economic activity from CO₂ emissions. A number of central and northern European countries and the US have shown how it is indeed possible to grow an economy while reducing emissions.

Other positive signs from our analysis include the 14% per year growth of global renewable energy (largely solar and wind) – albeit from a low base – and the fact that global coal consumption is still below its 2014 peak.


Read more: World greenhouse gas levels made unprecedented leap in 2016


These trends, and the resolute commitment of many countries to make the Paris Agreement a success, suggest that CO₂ emissions may not return to the high-growth rates experienced in the 2000s. However, an actual decline in global emissions might still be beyond our immediate reach, especially given projections for stronger economic growth in 2018.

The ConversationTo stabilise our climate at well below 2℃ of global warming, the elusive peak in global emissions needs to be reached as soon as possible, before quickly setting into motion the great decline in emissions needed to reach zero net emissions by around 2050.

Pep Canadell, CSIRO Scientist, and Executive Director of the Global Carbon Project, CSIRO; Corinne Le Quéré, Professor, Tyndall Centre for Climate Change Research, University of East Anglia; Glen Peters, Research Director, Center for International Climate and Environment Research – Oslo; Robbie Andrew, Senior Researcher, Center for International Climate and Environment Research – Oslo; Rob Jackson, Chair, Department of Earth System Science, and Chair of the Global Carbon Project, globalcarbonproject.org, Stanford University, and Vanessa Haverd, Senior research scientist, CSIRO

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

Antarctic ice reveals that fossil fuel extraction leaks more methane than thought



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The analysis of large amounts of ice from Antarctica’s Taylor Valley has helped scientists to tease apart the natural and human-made sources of the potent greenhouse gas methane.
Hinrich Schaefer, CC BY-ND

Hinrich Schaefer, National Institute of Water and Atmospheric

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

A greenhouse gas history

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?

Antarctic ice traps tiny bubbles of air, which represents a sample of ancient atmospheres.
Hinrich Schaefer, CC BY-ND

The time capsule

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 ice

The 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.

A tonne of ice yielded only a drop of methane.
Hinrich Schaefer, CC BY-ND

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 bomb

Because 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%.

The ConversationMeasurements 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.

Hinrich Schaefer, Research Scientist Trace Gases, National Institute of Water and Atmospheric

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

Noise from offshore oil and gas surveys can affect whales up to 3km away



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Migrating humpback whales avoid loud, nearby sounds.
BRAHSS, Author provided

Rebecca Dunlop, The University of Queensland and Michael Noad, The University of Queensland

Air guns used for marine oil and gas exploration are loud enough to affect humpback whales up to 3km away, potentially affecting their migration patterns, according to our new research.

Whales’ communication depends on loud sounds, which can travel very efficiently over distances of tens of kilometres in the underwater environment. But our study, published today in the Journal of Experimental Biology, shows that they are affected by other loud ocean noises produced by humans.

As part of the BRAHSS (Behavioural Response of Humpback whales to Seismic Surveys) project, we and our colleagues measured humpback whales’ behavioural responses to air guns like those used in seismic surveys carried out by the offshore mining industry.


Read more: It’s time to speak up about noise pollution in the oceans


Air guns are devices towed behind seismic survey ships that rapidly release compressed air into the ocean, producing a loud bang. The sound travels through the water and into the sea bed, bouncing off various layers of rock, oil or gas. The faint echoes are picked up by sensors towed by the same vessel.

During surveys, the air guns are fired every 10-15 seconds to develop a detailed geological picture of the ocean floor in the area. Although they are not intended to harm whales, there has been concern for many years about the potential impacts of these loud, frequent sounds.

Sound research

Although it sounds like a simple experiment to expose whales to air guns and see what they do, it is logistically difficult. For one thing, the whales may respond to the presence of the ship towing the air guns, rather than the air guns themselves. Another problem is that humpback whales tend to show a lot of natural behavioural variability, making it difficult to tease out the effect of the air gun and ship.

There is also the question of whether any response by the whales is influenced more by the loudness of the air gun, or how close the air blast is to the whale (although obviously the two are linked). Previous studies have assumed that the response is driven primarily by loudness, but we also looked at the effect of proximity.

We used a small air gun and a cluster of guns, towed behind a vessel through the migratory path of more than 120 groups of humpback whales off Queensland’s sunshine coast. By having two different sources, one louder than the other, we were able to fire air blasts of different perceived loudness from the same distance.

We found that whales slowed their migratory speed and deviated around the vessel and the air guns. This response was influenced by a combination of received level and proximity; both were necessary. The whales were affected up to 3km away, at sound levels over 140 decibels, and deviated from their path by about 500 metres. Within this “zone”, whales were more likely to avoid the air guns.

Each tested group moved as one, but our analysis did not include the effects on different group types, such as a female with calf versus a group of adults, for instance.

The ConversationOur results suggest that when regulating to reduce the impact of loud noise on whale behaviour, we need to take into account not just how loud the noise is, but how far away it is. More research is needed to find out how drastically the whales’ migration routes change as a result of ocean mining noise.

Rebecca Dunlop, Senior Lecturer in Physiology, The University of Queensland and Michael Noad, Associate Professor, The University of Queensland

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