Tag Archives: Methane

Early rain as Arctic warms means more methane

As spring advances, so does the rain to warm the permafrost. It means more methane can get into the atmosphere to accelerate global warming.

LONDON, 18 February, 2019 − As the global temperature steadily rises, it ensures that levels of one of the most potent greenhouse gases are increasing in a way new to science: the planet will have to reckon with more methane than expected.

Researchers who monitored one bog for three years in the Alaskan permafrost have identified yet another instance of what engineers call positive feedback. They found that global warming meant earlier springs and with that, earlier spring rains.

And as a consequence, the influx of warm water on what had previously been frozen ground triggered a biological frenzy that sent methane emissions soaring.

One stretch of wetland in a forest of black spruce in the Alaskan interior stepped up its emissions of natural gas (another name for methane) by 30%. Methane is a greenhouse gas at least 30 times more potent than carbon dioxide.

“The microbes in this bog on some level are like ‘Oh man, we’re stuck making methane because that’s all this bog is allowing us to do’”

As a consequence, climate scientists may have to return yet again to the vexed question of the carbon budget, in their calculations of how fast the world will warm as humans burn more fossil fuels, to set up ever more rapid global warming and climate change, which will in turn accelerate the thawing of the permafrost.

The evidence so far comes from a detailed study of water, energy and carbon traffic from just one wetland. But other teams of scientists have repeatedly expressed concern about the integrity of the northern hemisphere permafrost and the vast stores of carbon preserved in the frozen soils, beneath the shallow layer that comes to life with each Arctic spring.

“We saw the plants going crazy and methane emissions going bonkers,” said Rebecca Neumann, an environmental engineer at the University of Washington in Seattle, who led the study. “2016 had above average rainfall, but so did 2014. So what was different about this year?”

What mattered was when the rain fell: it fell earlier, when the ground was still colder than the air. The warmer water saturated the frozen forest, flowed into the bog, and created a local permafrost thaw in anoxic conditions: the subterranean microbial communities responded by converting the once-frozen organic matter into a highly effective greenhouse gas.

Alarm rises

“It’d be the bottom of the barrel in terms of energy production for them,” Dr Neumann said. “The microbes in this bog on some level are like ‘Oh man, we’re stuck making methane because that’s all this bog is allowing us to do’.”

As global average temperature levels creep up, so does alarm about the state of the vast tracts of permafrost, home to huge stores of frozen carbon in the form of semi-decayed plant material that could be released into the atmosphere to fuel further global warming, with devastating consequences.

Spring has been arriving earlier everywhere in the northern hemisphere, including the Arctic, with unpredictable impacts on high latitude ecosystems.

The permafrost itself has been identified as a vulnerable region, change in which could tip the planet into a new and unpredictable climate regime, and geographers only this year have started to assess the direct hazard to the communities that live in the high latitudes as once-solid ground turns to slush under their feet.

More evaporation

Much more difficult to assess is how the steady attrition of the permafrost plays out in terms of the traffic of carbon between rocks, ocean, atmosphere and living things: researchers are still teasing out the roles of all the agencies at work, including subterranean microbes.

In a warmer world, evaporation will increase. Warmer air has a greater capacity for water vapour. In the end, it means more rain will fall. If it falls in spring or early summer, the research from one marshland in Alaska seems to suggest, more methane will escape into the atmosphere.

Right now, the rewards of the study are academic. They throw just a little more light on the subtle machinery of weather and climate. The test is whether what happens in one instance is likely to happen in other, similar terrain around the high latitudes.

“The ability of rain to transport thermal energy into soils has been under-appreciated,” Dr Neumann said. “Our study shows that by affecting soil temperature and methane emissions, rain can increase the ability of thawing permafrost to warm the climate.” − Climate News Network

As spring advances, so does the rain to warm the permafrost. It means more methane can get into the atmosphere to accelerate global warming.

LONDON, 18 February, 2019 − As the global temperature steadily rises, it ensures that levels of one of the most potent greenhouse gases are increasing in a way new to science: the planet will have to reckon with more methane than expected.

Researchers who monitored one bog for three years in the Alaskan permafrost have identified yet another instance of what engineers call positive feedback. They found that global warming meant earlier springs and with that, earlier spring rains.

And as a consequence, the influx of warm water on what had previously been frozen ground triggered a biological frenzy that sent methane emissions soaring.

One stretch of wetland in a forest of black spruce in the Alaskan interior stepped up its emissions of natural gas (another name for methane) by 30%. Methane is a greenhouse gas at least 30 times more potent than carbon dioxide.

“The microbes in this bog on some level are like ‘Oh man, we’re stuck making methane because that’s all this bog is allowing us to do’”

As a consequence, climate scientists may have to return yet again to the vexed question of the carbon budget, in their calculations of how fast the world will warm as humans burn more fossil fuels, to set up ever more rapid global warming and climate change, which will in turn accelerate the thawing of the permafrost.

The evidence so far comes from a detailed study of water, energy and carbon traffic from just one wetland. But other teams of scientists have repeatedly expressed concern about the integrity of the northern hemisphere permafrost and the vast stores of carbon preserved in the frozen soils, beneath the shallow layer that comes to life with each Arctic spring.

“We saw the plants going crazy and methane emissions going bonkers,” said Rebecca Neumann, an environmental engineer at the University of Washington in Seattle, who led the study. “2016 had above average rainfall, but so did 2014. So what was different about this year?”

What mattered was when the rain fell: it fell earlier, when the ground was still colder than the air. The warmer water saturated the frozen forest, flowed into the bog, and created a local permafrost thaw in anoxic conditions: the subterranean microbial communities responded by converting the once-frozen organic matter into a highly effective greenhouse gas.

Alarm rises

“It’d be the bottom of the barrel in terms of energy production for them,” Dr Neumann said. “The microbes in this bog on some level are like ‘Oh man, we’re stuck making methane because that’s all this bog is allowing us to do’.”

As global average temperature levels creep up, so does alarm about the state of the vast tracts of permafrost, home to huge stores of frozen carbon in the form of semi-decayed plant material that could be released into the atmosphere to fuel further global warming, with devastating consequences.

Spring has been arriving earlier everywhere in the northern hemisphere, including the Arctic, with unpredictable impacts on high latitude ecosystems.

The permafrost itself has been identified as a vulnerable region, change in which could tip the planet into a new and unpredictable climate regime, and geographers only this year have started to assess the direct hazard to the communities that live in the high latitudes as once-solid ground turns to slush under their feet.

More evaporation

Much more difficult to assess is how the steady attrition of the permafrost plays out in terms of the traffic of carbon between rocks, ocean, atmosphere and living things: researchers are still teasing out the roles of all the agencies at work, including subterranean microbes.

In a warmer world, evaporation will increase. Warmer air has a greater capacity for water vapour. In the end, it means more rain will fall. If it falls in spring or early summer, the research from one marshland in Alaska seems to suggest, more methane will escape into the atmosphere.

Right now, the rewards of the study are academic. They throw just a little more light on the subtle machinery of weather and climate. The test is whether what happens in one instance is likely to happen in other, similar terrain around the high latitudes.

“The ability of rain to transport thermal energy into soils has been under-appreciated,” Dr Neumann said. “Our study shows that by affecting soil temperature and methane emissions, rain can increase the ability of thawing permafrost to warm the climate.” − Climate News Network

Oil’s methane emissions higher than feared

methane emissions

New study shows that oil production can result in methane emissions up to twice as high as estimated by ‘simplistic’ data collection systems.

LONDON, 6 February, 2017 – Global methane emissions from oil production between 1980 and 2012 were far higher than previously thought – in some cases, as much as double the amount previously estimated, according to a new scientific study

The reason for the discrepancy is simple. The author of the study − which also includes emissions of another gas, ethane − says it is the first to take into account different production management systems and geological conditions around the world.

Lena Höglund-Isaksson, senior research scholar at the International Institute for Applied Systems Analysis (IIASA) in Laxenburg, Austria, describes the old figures, which were based on arguing that what happened in North American oilfields applied equally to the rest of the world, as “rather simplistic”.

The IIASA study, published in Environmental Research Letters journal, is another reminder that climate science – like all science – is only as dependable as the data on which it relies.

In a system as complex as the atmosphere, faulty data can have far-reaching consequences.

Potent greenhouse gas

Methane is a potent greenhouse gas − the most important contributor to climate change after carbon dioxide. There is now international agreement that methane is 34 times more potent than CO2 over a century, but 84 times more over a much shorter timespan – just 20 years.

Yet while methane concentrations in the atmosphere can easily be measured, it is much harder to establish how much the different sources, whether human or natural, contribute to the total. This information is needed to work out how to reduce emissions.

Dr Höglund-Isaksson explains: “In an oil reservoir, there is a layer of gas above the oil that has a methane content of 50% to 85%. When you pump the oil to the surface, this associated gas will also escape.”

In oil production in North America, she says, almost all of this gas is recovered, and most of the small amount that is not will be flared to prevent leakage − and possible explosions. A very small amount is simply vented.

In other parts of the world, where gas recovery rates are lower, much larger quantities of methane emissions are released into the atmosphere.

“In an oil reservoir, there is a layer of gas above
the oil that has a methane content of 50% to 85%”

“Existing global bottom-up emission inventories of methane used rather simplistic approaches for estimating methane from oil production, merely taking the few direct measurements that exist from North American oil fields and scaling them with oil production worldwide,” says Dr Höglund-Isaksson.

(Bottom-up, in this context, involves multiplying the production of oil by the amount of methane released per unit of oil produced).

This approach left ample room for error, so she decided to find a new method to provide a better explanation for the global variations.

In the new study, Dr Höglund-Isaksson estimated global methane emissions from oil and gas systems in over 100 countries over a 32-year period, using country-specific data ranging from reported volumes of associated gas to satellite imagery that can show flaring.

She also used atmospheric measurements of ethane, a gas that is released along with methane and is easier to link more directly to oil and gas activities.

Dr Höglund-Isaksson found that global methane emissions, particularly in the 1980s, were as much as double previous estimates.

Russia’s methane emissions

The study also found that the Russian oil industry contributes a large amount to the methane emissions.

A decline in the Russian oil industry in the 1990s contributed to a global decline in emissions, which continued until the early 2000s. That was when methane recovery systems were becoming more common and also helping to reduce emissions.

But since 2005, emissions from oil and gas systems have remained fairly constant, which Dr Höglund-Isaksson says is probably linked to increasing shale gas production, which largely offsets emission reductions achieved through increased gas recovery.

She says that there is still uncertainty in the numbers, and that improving the data requires close collaboration between the scientific measurement community and the oil and gas industry to make more direct measurements available from different parts of the world.

The good news is that her research promises more accurate measurements of how much methane is in the atmosphere.

The less good news is that just how much is there appears to be increasing rapidly – faster than at any time this century. – Climate News Network

New study shows that oil production can result in methane emissions up to twice as high as estimated by ‘simplistic’ data collection systems.

LONDON, 6 February, 2017 – Global methane emissions from oil production between 1980 and 2012 were far higher than previously thought – in some cases, as much as double the amount previously estimated, according to a new scientific study

The reason for the discrepancy is simple. The author of the study − which also includes emissions of another gas, ethane − says it is the first to take into account different production management systems and geological conditions around the world.

Lena Höglund-Isaksson, senior research scholar at the International Institute for Applied Systems Analysis (IIASA) in Laxenburg, Austria, describes the old figures, which were based on arguing that what happened in North American oilfields applied equally to the rest of the world, as “rather simplistic”.

The IIASA study, published in Environmental Research Letters journal, is another reminder that climate science – like all science – is only as dependable as the data on which it relies.

In a system as complex as the atmosphere, faulty data can have far-reaching consequences.

Potent greenhouse gas

Methane is a potent greenhouse gas − the most important contributor to climate change after carbon dioxide. There is now international agreement that methane is 34 times more potent than CO2 over a century, but 84 times more over a much shorter timespan – just 20 years.

Yet while methane concentrations in the atmosphere can easily be measured, it is much harder to establish how much the different sources, whether human or natural, contribute to the total. This information is needed to work out how to reduce emissions.

Dr Höglund-Isaksson explains: “In an oil reservoir, there is a layer of gas above the oil that has a methane content of 50% to 85%. When you pump the oil to the surface, this associated gas will also escape.”

In oil production in North America, she says, almost all of this gas is recovered, and most of the small amount that is not will be flared to prevent leakage − and possible explosions. A very small amount is simply vented.

In other parts of the world, where gas recovery rates are lower, much larger quantities of methane emissions are released into the atmosphere.

“In an oil reservoir, there is a layer of gas above
the oil that has a methane content of 50% to 85%”

“Existing global bottom-up emission inventories of methane used rather simplistic approaches for estimating methane from oil production, merely taking the few direct measurements that exist from North American oil fields and scaling them with oil production worldwide,” says Dr Höglund-Isaksson.

(Bottom-up, in this context, involves multiplying the production of oil by the amount of methane released per unit of oil produced).

This approach left ample room for error, so she decided to find a new method to provide a better explanation for the global variations.

In the new study, Dr Höglund-Isaksson estimated global methane emissions from oil and gas systems in over 100 countries over a 32-year period, using country-specific data ranging from reported volumes of associated gas to satellite imagery that can show flaring.

She also used atmospheric measurements of ethane, a gas that is released along with methane and is easier to link more directly to oil and gas activities.

Dr Höglund-Isaksson found that global methane emissions, particularly in the 1980s, were as much as double previous estimates.

Russia’s methane emissions

The study also found that the Russian oil industry contributes a large amount to the methane emissions.

A decline in the Russian oil industry in the 1990s contributed to a global decline in emissions, which continued until the early 2000s. That was when methane recovery systems were becoming more common and also helping to reduce emissions.

But since 2005, emissions from oil and gas systems have remained fairly constant, which Dr Höglund-Isaksson says is probably linked to increasing shale gas production, which largely offsets emission reductions achieved through increased gas recovery.

She says that there is still uncertainty in the numbers, and that improving the data requires close collaboration between the scientific measurement community and the oil and gas industry to make more direct measurements available from different parts of the world.

The good news is that her research promises more accurate measurements of how much methane is in the atmosphere.

The less good news is that just how much is there appears to be increasing rapidly – faster than at any time this century. – Climate News Network

Methane’s rapid spurt risks climate curbs plan

A recent rapid rise in methane could damage global attempts to slow climate change through cuts in carbon dioxide emissions.

LONDON, 12 December, 2016 – One year ago today, with huge relief, scarcely able to believe their achievement, world leaders finally agreed to reduce emissions of carbon dioxide.

But a bare 12 months later comes sobering news: atmospheric concentrations of another gas, methane, are growing faster than at any time in the last 20 years, putting further pressure on the historic Paris Agreement to deliver substantial cuts in emissions very soon.

Some scientists say the world now needs to change course and do more about methane to have a chance of keeping average global temperatures from rising by more than 2°C.

And one seasoned Arctic watcher says the changes there in the last decade are altering a system which has remained intact since the Ice Age.

Methane is the second major greenhouse gas, with agriculture accounting for 40% of emissions. Over a century it is 34 times more powerful as a greenhouse gas than carbon dioxide (though far less abundant), but over 20 years methane is 84 times more potent than CO2

In an editorial in the journal Environmental Research Letters, an international team of scientists reports that methane concentrations in the air began to surge around 2007 and grew steeply in 2014 and 2015. In those two years concentrations rose by 10 or more parts per billion annually. In the early 2000s they had been rising by an annual average of 0.5 ppb.

Mitigation possible

The scientists say the reason for the spike is unclear, but they think it may be the consequence of emissions from agricultural sources and mainly around the tropics – possibly from farm sites like rice paddies and cattle pastures.

They say research shows that the growth of CO2 emissions has flattened out in recent years, just as methanes seem to be soaring. 

Rob Jackson, a co-author of the editorial and professor of earth system science at Stanford University, US, says the methane findings are worrisome but provide an immediate opportunity for mitigation that complements efforts for carbon dioxide.

He and his fellow authors helped to produce the 2016 Global Methane Budget, a comprehensive look at how methane flowed in and out of the atmosphere from 2000 to 2012 because of human activities and other factors. The budget is published by the Global Carbon Project, a research initiative of Future Earth.

“The methane being released now, at an accelerating rate, could easily negate the carbon reductions we are making” 

Peter Wadhams, emeritus professor of ocean physics at Cambridge University, says scientists are now seeing large plumes of methane escaping from the shallow seas north of Siberia. These emissions, and those from the thawing tundra, are contributing to the sudden rise in methane concentrations.

Professor Wadhams devotes part of his new book A Farewell to Ice  to the subject. He told the Climate News Network: “The methane being released now, at an accelerating rate, could easily negate the carbon reductions we are making.

“A Russian expedition which returned from the Arctic recently estimates there’s so much methane in offshore sediments that if it all escaped it would mean an immediate temperature rise of about 0.6°C. And there’s quite a big chance of a total melt.

“I’ve been going to the Arctic for over 40 years, and this is entirely new. The melting sea ice   has allowed the water temperature to rise to 7°C since about 2005, affecting the permafrost which had till then remained unchanged since the Ice Age. The methane plumes are an amazing sight, a mass of bubbles erupting from the sea surface.”

And releases of methane from the sea floor are not restricted to the shallow Arctic waters: one of the places they are occurring as well is in the north Pacific

Rapid reversal

Methane comes from a variety of sources, including wild areas like marshes and wetlands, and fossil fuel exploration. About 60% of the gas which enters the atmosphere annually comes from human activities, notably agriculture.

Marielle Saunois, lead author of the ERL paper, from Versailles Saint-Quentin-en-Yvelines University (UVSQ), France, says the world should do more about methane emissions: If we want to stay below two degrees temperature increase, we should not follow this track and need to make a rapid turn-around.

Saunois says that, on available data, she and her colleagues think agricultural growth is the likelier source, at least for now, of rising methane than expanded natural gas drilling.

When it comes to methane, there has been a lot of focus on the fossil fuel industry, but we need to look just as hard if not harder at agriculture, Professor Jackson says. The situation certainly isnt hopeless. Its a real opportunity. Climate News Network

A recent rapid rise in methane could damage global attempts to slow climate change through cuts in carbon dioxide emissions.

LONDON, 12 December, 2016 – One year ago today, with huge relief, scarcely able to believe their achievement, world leaders finally agreed to reduce emissions of carbon dioxide.

But a bare 12 months later comes sobering news: atmospheric concentrations of another gas, methane, are growing faster than at any time in the last 20 years, putting further pressure on the historic Paris Agreement to deliver substantial cuts in emissions very soon.

Some scientists say the world now needs to change course and do more about methane to have a chance of keeping average global temperatures from rising by more than 2°C.

And one seasoned Arctic watcher says the changes there in the last decade are altering a system which has remained intact since the Ice Age.

Methane is the second major greenhouse gas, with agriculture accounting for 40% of emissions. Over a century it is 34 times more powerful as a greenhouse gas than carbon dioxide (though far less abundant), but over 20 years methane is 84 times more potent than CO2

In an editorial in the journal Environmental Research Letters, an international team of scientists reports that methane concentrations in the air began to surge around 2007 and grew steeply in 2014 and 2015. In those two years concentrations rose by 10 or more parts per billion annually. In the early 2000s they had been rising by an annual average of 0.5 ppb.

Mitigation possible

The scientists say the reason for the spike is unclear, but they think it may be the consequence of emissions from agricultural sources and mainly around the tropics – possibly from farm sites like rice paddies and cattle pastures.

They say research shows that the growth of CO2 emissions has flattened out in recent years, just as methanes seem to be soaring. 

Rob Jackson, a co-author of the editorial and professor of earth system science at Stanford University, US, says the methane findings are worrisome but provide an immediate opportunity for mitigation that complements efforts for carbon dioxide.

He and his fellow authors helped to produce the 2016 Global Methane Budget, a comprehensive look at how methane flowed in and out of the atmosphere from 2000 to 2012 because of human activities and other factors. The budget is published by the Global Carbon Project, a research initiative of Future Earth.

“The methane being released now, at an accelerating rate, could easily negate the carbon reductions we are making” 

Peter Wadhams, emeritus professor of ocean physics at Cambridge University, says scientists are now seeing large plumes of methane escaping from the shallow seas north of Siberia. These emissions, and those from the thawing tundra, are contributing to the sudden rise in methane concentrations.

Professor Wadhams devotes part of his new book A Farewell to Ice  to the subject. He told the Climate News Network: “The methane being released now, at an accelerating rate, could easily negate the carbon reductions we are making.

“A Russian expedition which returned from the Arctic recently estimates there’s so much methane in offshore sediments that if it all escaped it would mean an immediate temperature rise of about 0.6°C. And there’s quite a big chance of a total melt.

“I’ve been going to the Arctic for over 40 years, and this is entirely new. The melting sea ice   has allowed the water temperature to rise to 7°C since about 2005, affecting the permafrost which had till then remained unchanged since the Ice Age. The methane plumes are an amazing sight, a mass of bubbles erupting from the sea surface.”

And releases of methane from the sea floor are not restricted to the shallow Arctic waters: one of the places they are occurring as well is in the north Pacific

Rapid reversal

Methane comes from a variety of sources, including wild areas like marshes and wetlands, and fossil fuel exploration. About 60% of the gas which enters the atmosphere annually comes from human activities, notably agriculture.

Marielle Saunois, lead author of the ERL paper, from Versailles Saint-Quentin-en-Yvelines University (UVSQ), France, says the world should do more about methane emissions: If we want to stay below two degrees temperature increase, we should not follow this track and need to make a rapid turn-around.

Saunois says that, on available data, she and her colleagues think agricultural growth is the likelier source, at least for now, of rising methane than expanded natural gas drilling.

When it comes to methane, there has been a lot of focus on the fossil fuel industry, but we need to look just as hard if not harder at agriculture, Professor Jackson says. The situation certainly isnt hopeless. Its a real opportunity. Climate News Network

Useful waste offers win-win benefits

An unsung success story in the switch to renewable energy is the use of waste to produce gas – and a valuable by-product.

LONDON, 2 February, 2016 – The future is increasingly bright for renewable energy, with the US aiming to cut the price of solar photovoltaics by 75% between 2010 and 2020. Denmark plans to obtain 50% of its energy from wind just five years from now.

But one form of renewable energy – and one which attracts few headlines – manages to create two useful products at the same time, and is making a growing contribution to combatting climate change.

The medieval alchemists who sought to turn base metal into gold would have thrilled at   chemistry that let them turn waste into both fuel and fertiliser. Their twenty-first century successors have discovered the secret of doing exactly that. 

Unwanted food, animal waste, municipal rubbish, crop and forestry residues, sewage and dozens of other left-overs of civilisation can and are now being turned into methane to generate electricity, provide district heating and to fuel road vehicles.

Big contribution

This largely unheralded revolution takes different forms across the world, mostly because governments set their own rules to encourage the technology, and also because local circumstances provide contrasting piles of waste. But in every case the waste can be converted into gas for use as fuel.

Although the technology is only part of the solution to climate change, the European Biogas  Association estimates that over time it should be able to replace 30% of current natural gas consumption in Europe.

The technology is roughly the same whatever the size of the plant or its location. Biogas plants use microbes to eat waste in an oxygen-free environment to produce methane, and leave fertiliser or soil conditioner as a useful by-product. The plants vary from small household types, very popular in China and India, to farm plants and larger-scale municipal installations in Europe.

Poor relation

The potential of wind and solar power for replacing coal to produce electricity is familiar;  the biogas revolution is hardly recognised. The first report on biogas produced by the International Gas Union went virtually unreported.

Yet its details included, for example: “One bag of food waste composted to biogas is enough to power a gas-driven car for almost two kilometres”, and: “A bus with 55 passengers can run for 1,000 km on the food waste produced by its passengers each year.”

Biogas is produced naturally in environments with no oxygen: swamps, for example, rice paddies and the stomachs of ruminant animals like cattle. An anaerobic digester’s microbes produce the methane by eating the organic content of the waste, leaving a nutrient-rich fertiliser as the residue.

Germany and China are the world leaders in turning farm waste into gas, with 8,000 and 24,000 farm-based plants respectively. More surprising perhaps is the fact that China has built 42 million small biogas plants in a decade to turn village waste into fuel.

Compatible mix

Usually the methane produced in these digesters is fed into generators or small power stations on site and used locally. But if it is further purified the gas can simply be fed into a pipeline and mixed with natural gas.

In Sweden, which aims by 2030 to replace fossil fuels in transport with biogas, the number of gas-driven vehicles has doubled to 50,000 in the last five years. One Swedish advance is to cool the gas to -163°C until it liquefies, reducing its volume by 600 times and making it a perfect fuel for large lorries. Demand for biogas outstrips supply in much of the country, which is now using its ample supplies of forestry waste.

Elsewhere, for example in the UK and South Korea, much biogas comes from old rubbish dumps where the methane they emit is piped to mini-power stations on site. More recently, to cut down on waste, local authorities in the UK have begun collecting thrown-away food so that purpose-built anaerobic digesters can convert it into gas and fertiliser.

Scotland, although part of the UK, has a devolved government which recognises that stronger regulation can drive the biogas revolution. – Climate News Network

An unsung success story in the switch to renewable energy is the use of waste to produce gas – and a valuable by-product.

LONDON, 2 February, 2016 – The future is increasingly bright for renewable energy, with the US aiming to cut the price of solar photovoltaics by 75% between 2010 and 2020. Denmark plans to obtain 50% of its energy from wind just five years from now.

But one form of renewable energy – and one which attracts few headlines – manages to create two useful products at the same time, and is making a growing contribution to combatting climate change.

The medieval alchemists who sought to turn base metal into gold would have thrilled at   chemistry that let them turn waste into both fuel and fertiliser. Their twenty-first century successors have discovered the secret of doing exactly that. 

Unwanted food, animal waste, municipal rubbish, crop and forestry residues, sewage and dozens of other left-overs of civilisation can and are now being turned into methane to generate electricity, provide district heating and to fuel road vehicles.

Big contribution

This largely unheralded revolution takes different forms across the world, mostly because governments set their own rules to encourage the technology, and also because local circumstances provide contrasting piles of waste. But in every case the waste can be converted into gas for use as fuel.

Although the technology is only part of the solution to climate change, the European Biogas  Association estimates that over time it should be able to replace 30% of current natural gas consumption in Europe.

The technology is roughly the same whatever the size of the plant or its location. Biogas plants use microbes to eat waste in an oxygen-free environment to produce methane, and leave fertiliser or soil conditioner as a useful by-product. The plants vary from small household types, very popular in China and India, to farm plants and larger-scale municipal installations in Europe.

Poor relation

The potential of wind and solar power for replacing coal to produce electricity is familiar;  the biogas revolution is hardly recognised. The first report on biogas produced by the International Gas Union went virtually unreported.

Yet its details included, for example: “One bag of food waste composted to biogas is enough to power a gas-driven car for almost two kilometres”, and: “A bus with 55 passengers can run for 1,000 km on the food waste produced by its passengers each year.”

Biogas is produced naturally in environments with no oxygen: swamps, for example, rice paddies and the stomachs of ruminant animals like cattle. An anaerobic digester’s microbes produce the methane by eating the organic content of the waste, leaving a nutrient-rich fertiliser as the residue.

Germany and China are the world leaders in turning farm waste into gas, with 8,000 and 24,000 farm-based plants respectively. More surprising perhaps is the fact that China has built 42 million small biogas plants in a decade to turn village waste into fuel.

Compatible mix

Usually the methane produced in these digesters is fed into generators or small power stations on site and used locally. But if it is further purified the gas can simply be fed into a pipeline and mixed with natural gas.

In Sweden, which aims by 2030 to replace fossil fuels in transport with biogas, the number of gas-driven vehicles has doubled to 50,000 in the last five years. One Swedish advance is to cool the gas to -163°C until it liquefies, reducing its volume by 600 times and making it a perfect fuel for large lorries. Demand for biogas outstrips supply in much of the country, which is now using its ample supplies of forestry waste.

Elsewhere, for example in the UK and South Korea, much biogas comes from old rubbish dumps where the methane they emit is piped to mini-power stations on site. More recently, to cut down on waste, local authorities in the UK have begun collecting thrown-away food so that purpose-built anaerobic digesters can convert it into gas and fertiliser.

Scotland, although part of the UK, has a devolved government which recognises that stronger regulation can drive the biogas revolution. – Climate News Network

Arctic methane emissions persist in winter

Methane, a key greenhouse gas, is released from Arctic soils not only in the short summer period but during the bitterly cold winters too. 

LONDON, 22 December, 2015 – The quantity of methane leaking from the frozen soil during the long Arctic winters is probably much greater than climate models estimate, scientists have found.

They say at least half of annual methane emissions occur in the cold months from September to May, and that drier, upland tundra can emit more methane than wetlands.

The multinational team, led by San Diego State University (SDSU) in the US and including colleagues from the National Oceanic and Atmospheric Administration, and the University of Sheffield and the Open University in the UK, have published their conclusion, which challenges critical assumptions in current global climate models, in the Proceedings of the National Academy of Sciences.

Methane, a potent greenhouse gas, is about 25 times more powerful per molecule than carbon dioxide over a century, but more than 84 times over 20 years. The methane in the Arctic tundra comes primarily from organic matter trapped in soil which thaws seasonally and is decomposed by microbes.

It seeps naturally from the soil over the course of the year, but climate change can warm the soil enough to release more methane from organic matter that is currently stable in the permafrost

“Virtually all the climate models assume there’s no or very little emission of methane when the ground is frozen. That assumption is incorrect”

Scientists have for some years been accurately measuring Arctic methane emissions and incorporating the results into their climate models. But crucially, the SDSU team says, almost all of these measurements have been obtained during the Arctic’s short summer.

Its long cold period has been largely “overlooked and ignored,” according to Walter Oechel of SDSU, with most researchers thinking that, because the ground is frozen solid during the cold months, methane emissions practically shut down for the winter.

“Virtually all the climate models assume there’s no or very little emission of methane when the ground is frozen,” he says. “That assumption is incorrect.”

The authors say the water trapped in the soil doesn’t freeze completely at 0°C. The top layer of the ground – known as the active layer – thaws in the summer and refreezes in the winter, and it experiences a kind of sandwiching effect as it freezes.

When temperatures are around 0°C (called “the zero curtain”) the top and bottom of the active layer begin to freeze, but the middle remains insulated. Micro-organisms in this unfrozen layer continue to break down organic matter and emit methane many months into the Arctic winter.

Dual approach

To find out how much methane is emitted during the winter, the researchers used both ground-based and airborne methods.

The ground-based researchers recorded methane emissions from five sampling towers in Alaska over two summer-autumn-winter cycles between June 2013 and January 2015 and found that a major part of winter emissions was recorded when temperatures hovered near the zero curtain.

“This is extremely relevant for the Arctic ecosystem, as the zero curtain period continues from September until the end of December, lasting as long as or longer than the entire summer season,” said Donatella Zona, the study’s lead author.

“These results are the opposite of what modellers have been assuming, which is that the majority of the methane emissions occur during the warm summer months while the cold-season methane contribution is nearly zero.”

Data confirmed

The researchers also found that during the cold season methane emissions were higher at the drier, upland tundra sites than in the wetlands. Upland tundra had previously been assumed to contribute a negligible amount of methane, Zona said.

To test whether the site-specific sampling was typical of methane emissions across the Arctic, the researchers compared their results with measurements recorded during flights made by NASA’s Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE). 

The data from the ground-based sites proved well-matched with the larger-scale aircraft measurements, which showed that large areas of Arctic tundra and boreal forest continued to emit high levels of methane to the atmosphere long after the surface soil had frozen.

The team also used satellite microwave sensor measurements to develop regional maps of surface water cover, including the timing, extent and duration of seasonal flooding and drying of the region’s wetlands. This showed that the big methane-emitting areas were in the drier tundra. – Climate News Network

Methane, a key greenhouse gas, is released from Arctic soils not only in the short summer period but during the bitterly cold winters too. 

LONDON, 22 December, 2015 – The quantity of methane leaking from the frozen soil during the long Arctic winters is probably much greater than climate models estimate, scientists have found.

They say at least half of annual methane emissions occur in the cold months from September to May, and that drier, upland tundra can emit more methane than wetlands.

The multinational team, led by San Diego State University (SDSU) in the US and including colleagues from the National Oceanic and Atmospheric Administration, and the University of Sheffield and the Open University in the UK, have published their conclusion, which challenges critical assumptions in current global climate models, in the Proceedings of the National Academy of Sciences.

Methane, a potent greenhouse gas, is about 25 times more powerful per molecule than carbon dioxide over a century, but more than 84 times over 20 years. The methane in the Arctic tundra comes primarily from organic matter trapped in soil which thaws seasonally and is decomposed by microbes.

It seeps naturally from the soil over the course of the year, but climate change can warm the soil enough to release more methane from organic matter that is currently stable in the permafrost

“Virtually all the climate models assume there’s no or very little emission of methane when the ground is frozen. That assumption is incorrect”

Scientists have for some years been accurately measuring Arctic methane emissions and incorporating the results into their climate models. But crucially, the SDSU team says, almost all of these measurements have been obtained during the Arctic’s short summer.

Its long cold period has been largely “overlooked and ignored,” according to Walter Oechel of SDSU, with most researchers thinking that, because the ground is frozen solid during the cold months, methane emissions practically shut down for the winter.

“Virtually all the climate models assume there’s no or very little emission of methane when the ground is frozen,” he says. “That assumption is incorrect.”

The authors say the water trapped in the soil doesn’t freeze completely at 0°C. The top layer of the ground – known as the active layer – thaws in the summer and refreezes in the winter, and it experiences a kind of sandwiching effect as it freezes.

When temperatures are around 0°C (called “the zero curtain”) the top and bottom of the active layer begin to freeze, but the middle remains insulated. Micro-organisms in this unfrozen layer continue to break down organic matter and emit methane many months into the Arctic winter.

Dual approach

To find out how much methane is emitted during the winter, the researchers used both ground-based and airborne methods.

The ground-based researchers recorded methane emissions from five sampling towers in Alaska over two summer-autumn-winter cycles between June 2013 and January 2015 and found that a major part of winter emissions was recorded when temperatures hovered near the zero curtain.

“This is extremely relevant for the Arctic ecosystem, as the zero curtain period continues from September until the end of December, lasting as long as or longer than the entire summer season,” said Donatella Zona, the study’s lead author.

“These results are the opposite of what modellers have been assuming, which is that the majority of the methane emissions occur during the warm summer months while the cold-season methane contribution is nearly zero.”

Data confirmed

The researchers also found that during the cold season methane emissions were higher at the drier, upland tundra sites than in the wetlands. Upland tundra had previously been assumed to contribute a negligible amount of methane, Zona said.

To test whether the site-specific sampling was typical of methane emissions across the Arctic, the researchers compared their results with measurements recorded during flights made by NASA’s Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE). 

The data from the ground-based sites proved well-matched with the larger-scale aircraft measurements, which showed that large areas of Arctic tundra and boreal forest continued to emit high levels of methane to the atmosphere long after the surface soil had frozen.

The team also used satellite microwave sensor measurements to develop regional maps of surface water cover, including the timing, extent and duration of seasonal flooding and drying of the region’s wetlands. This showed that the big methane-emitting areas were in the drier tundra. – Climate News Network

Eat a plant and spare a tree

A less meat-intensive diet is essential for the sake of wildlife and forests and to slow climate change, says a report by UK-based researchers. LONDON, 31 August 2014 – Say goodbye to the steaks. Forget the foie gras. Put that pork chop away (assuming you can afford any of them). UK-based scientists say eating less meat is a vital part of tackling climate change. A study published in Nature Climate Change says that on present trends food production on its own will reach – and perhaps exceed – the global targets for total greenhouse gas emissions in 2050. Healthier diets – defined as meaning lower meat and dairy consumption – and reduced food waste are among the solutions needed to ensure food security and avoid dangerous climate change, the study says. More people, with more of us wanting meat-heavy Western diets, mean increasing farm yields will not meet the demands of an expected 9.6 billion humans. So we shall have to cultivate more land. This, the authors say, will mean more deforestation, more carbon emissions and further biodiversity loss, while extra livestock will raise methane levels.

Inefficient converters

Without radical changes, they expect cropland to expand by 42% by 2050 and fertiliser use by 45% (over 2009 levels). A further tenth of the world’s pristine tropical forests would disappear by mid-century. All this would cause GHG emissions from food production to increase by almost 80% by 2050 – roughly equal to the target GHG emissions by then for the entire global economy. They think halving food waste and managing demand for particularly environmentally-damaging food products – mainly from animals –  “might mitigate some” GHG emissions. “It is imperative to find ways to achieve global food security without expanding crop or pastureland,” said the lead researcher, Bojana Bajzelj, from the University of Cambridge’s department of engineering, who wrote the study with colleagues from Cambridge’s departments of geography and plant sciences and the University of Aberdeen’s Institute of Biological and Environmental Sciences. “The average efficiency of livestock converting plant feed to meat is less than 3%, and as we eat more meat, more arable cultivation is turned over to producing feedstock for animals… Agricultural practices are not necessarily at fault here – but our choice of food is.”

Squandered resources

This measure of efficiency is based on the units used in the study, which are grams of carbon in the biomass material, plant or meat. The team created a model that compares different scenarios for 2050, including some based on maintaining current trends. Another examines the closing of “yield gaps”. These gaps, between crop yields from best practice farming and actual average yields, exist everywhere but are widest in developing countries – particularly in sub-Saharan Africa. The researchers advocate closing the gaps through sustainable intensification of farming. But even then projected food demand will still demand additional land and more water and fertilisers – so the impact on emissions and biodiversity remains. Food waste occurs at all stages in the food chain, caused in developing countries by poor storage and transport and in the north by wasteful consumption. This squanders resources, especially energy, the authors say.

“As well as encouraging sustainable agriculture, we need to re-think what we eat”

Yield gap closure alone still shows a GHG increase of just over 40% by 2050. Closing yield gaps and halving food waste shows emissions increasing by 2%. But with healthy diets added too, the model suggests that agricultural GHG levels could fall by 48% from their 2009 level. The team says replacing diets containing too much food, especially emission-intensive meat and dairy products, with an average balanced diet avoiding excessive consumption of sugars, fats, and meat products, significantly reduces pressures on the environment even further. It says this “average” balanced diet is “a relatively achievable goal for most. For example, the figures included two 85g portions of red meat and five eggs per week, as well as a portion of poultry a day.” Co-author Professor Pete Smith from the University of Aberdeen said: “Unless we make some serious changes in food consumption trends, we would have to completely decarbonise the energy and industry sectors to stay within emissions budgets that avoid dangerous climate change. “That is practically impossible – so, as well as encouraging sustainable agriculture, we need to re-think what we eat.” – Climate News Network

A less meat-intensive diet is essential for the sake of wildlife and forests and to slow climate change, says a report by UK-based researchers. LONDON, 31 August 2014 – Say goodbye to the steaks. Forget the foie gras. Put that pork chop away (assuming you can afford any of them). UK-based scientists say eating less meat is a vital part of tackling climate change. A study published in Nature Climate Change says that on present trends food production on its own will reach – and perhaps exceed – the global targets for total greenhouse gas emissions in 2050. Healthier diets – defined as meaning lower meat and dairy consumption – and reduced food waste are among the solutions needed to ensure food security and avoid dangerous climate change, the study says. More people, with more of us wanting meat-heavy Western diets, mean increasing farm yields will not meet the demands of an expected 9.6 billion humans. So we shall have to cultivate more land. This, the authors say, will mean more deforestation, more carbon emissions and further biodiversity loss, while extra livestock will raise methane levels.

Inefficient converters

Without radical changes, they expect cropland to expand by 42% by 2050 and fertiliser use by 45% (over 2009 levels). A further tenth of the world’s pristine tropical forests would disappear by mid-century. All this would cause GHG emissions from food production to increase by almost 80% by 2050 – roughly equal to the target GHG emissions by then for the entire global economy. They think halving food waste and managing demand for particularly environmentally-damaging food products – mainly from animals –  “might mitigate some” GHG emissions. “It is imperative to find ways to achieve global food security without expanding crop or pastureland,” said the lead researcher, Bojana Bajzelj, from the University of Cambridge’s department of engineering, who wrote the study with colleagues from Cambridge’s departments of geography and plant sciences and the University of Aberdeen’s Institute of Biological and Environmental Sciences. “The average efficiency of livestock converting plant feed to meat is less than 3%, and as we eat more meat, more arable cultivation is turned over to producing feedstock for animals… Agricultural practices are not necessarily at fault here – but our choice of food is.”

Squandered resources

This measure of efficiency is based on the units used in the study, which are grams of carbon in the biomass material, plant or meat. The team created a model that compares different scenarios for 2050, including some based on maintaining current trends. Another examines the closing of “yield gaps”. These gaps, between crop yields from best practice farming and actual average yields, exist everywhere but are widest in developing countries – particularly in sub-Saharan Africa. The researchers advocate closing the gaps through sustainable intensification of farming. But even then projected food demand will still demand additional land and more water and fertilisers – so the impact on emissions and biodiversity remains. Food waste occurs at all stages in the food chain, caused in developing countries by poor storage and transport and in the north by wasteful consumption. This squanders resources, especially energy, the authors say.

“As well as encouraging sustainable agriculture, we need to re-think what we eat”

Yield gap closure alone still shows a GHG increase of just over 40% by 2050. Closing yield gaps and halving food waste shows emissions increasing by 2%. But with healthy diets added too, the model suggests that agricultural GHG levels could fall by 48% from their 2009 level. The team says replacing diets containing too much food, especially emission-intensive meat and dairy products, with an average balanced diet avoiding excessive consumption of sugars, fats, and meat products, significantly reduces pressures on the environment even further. It says this “average” balanced diet is “a relatively achievable goal for most. For example, the figures included two 85g portions of red meat and five eggs per week, as well as a portion of poultry a day.” Co-author Professor Pete Smith from the University of Aberdeen said: “Unless we make some serious changes in food consumption trends, we would have to completely decarbonise the energy and industry sectors to stay within emissions budgets that avoid dangerous climate change. “That is practically impossible – so, as well as encouraging sustainable agriculture, we need to re-think what we eat.” – Climate News Network

Wetland emissions mean more methane

FOR IMMEDIATE RELEASE Methane emissions are rising globally because wetlands – especially in northern latitudes – are releasing more than anyone had realised, a team of researchers based in Canada says. LONDON, 1 May – The bad news is that global emissions of methane appear to be rising. The worse news is that scientists believe there’s much more to come in the form of releases from many of the world’s wetlands. Methane is emitted from agriculture and fossil fuel use, as well as natural sources such as microbes in saturated wetland soils. It is a powerful greenhouse gas, and in the short term it does much more damage than the far more abundant carbon dioxide. Just how much more damaging it is is something scientists keep updating. There is now international agreement that methane is 34 times more potent than CO2 over a century, but 84 times more over a much shorter timespan – just 20 years. And two decades can be crucial in trying to slow the rate of climate change. Professor Merritt Turetsky, of the department of integrative biology at the University of Guelph, Canada, is the lead author of a paper published in the journal Global Change Biology. The paper is based on an analysis of global methane emissions examining almost 20,000 field data measurements collected from 70 sites across Arctic, temperate and tropical regions.

More to come

Professor Turetsky and her colleagues report that a recent rise in atmospheric methane probably stems from wetland emissions, suggesting that much more will escape into the atmosphere as northern wetlands continue to thaw and tropical ones to warm. The study supports calls for improved monitoring of wetlands and human changes to them. It also urges better methods of detecting different types of wetlands and different methane release rates between flooded and drained areas. The amount of atmospheric methane had remained relatively stable for about a decade, but concentrations began to rise again in 2007. Scientists assumed that wetland methane release was largest in the tropics, said Professor Turetsky. “But our analyses show that northern fens, such as those created when permafrost thaws, can have emissions comparable to warm sites in the tropics, despite their cold temperatures. That’s very important when it comes to scaling methane release at a global scale. “Not only are fens one of the strongest sources of wetland greenhouse gases, but we also know that Canadian forests and tundra underlain by permafrost are thawing and creating these kinds of high methane-producing ecosystems.”

Moisture the key

Most methane studies focus on measurements at a single site, said one of her co-authors, Narasinha Shurpali, from the University of Eastern Finland. “Our synthesis of data from a large number of observation points across the globe is unique and serves an important need.” The team showed that small temperature changes can release much more methane from wetland soils to the atmosphere than scientists had believed. Whether climate change will increase methane emissions will depend on soil moisture, said Professor Turetsky. Under warmer and wetter conditions, much more methane is likely to be emitted. If wetland soils dry out from evaporation or human drainage, though, emissions will fall – but not without other problems, like wildfires breaking out on drying peatlands. Another study co-author, Kim Wickland, of the United States Geological Survey, said: “This study provides important data for better accounting of how methane emissions change after wetland drainage and flooding.” She said emissions varied between those from natural wetlands and those from areas which had been disturbed or managed. – Climate News Network

FOR IMMEDIATE RELEASE Methane emissions are rising globally because wetlands – especially in northern latitudes – are releasing more than anyone had realised, a team of researchers based in Canada says. LONDON, 1 May – The bad news is that global emissions of methane appear to be rising. The worse news is that scientists believe there’s much more to come in the form of releases from many of the world’s wetlands. Methane is emitted from agriculture and fossil fuel use, as well as natural sources such as microbes in saturated wetland soils. It is a powerful greenhouse gas, and in the short term it does much more damage than the far more abundant carbon dioxide. Just how much more damaging it is is something scientists keep updating. There is now international agreement that methane is 34 times more potent than CO2 over a century, but 84 times more over a much shorter timespan – just 20 years. And two decades can be crucial in trying to slow the rate of climate change. Professor Merritt Turetsky, of the department of integrative biology at the University of Guelph, Canada, is the lead author of a paper published in the journal Global Change Biology. The paper is based on an analysis of global methane emissions examining almost 20,000 field data measurements collected from 70 sites across Arctic, temperate and tropical regions.

More to come

Professor Turetsky and her colleagues report that a recent rise in atmospheric methane probably stems from wetland emissions, suggesting that much more will escape into the atmosphere as northern wetlands continue to thaw and tropical ones to warm. The study supports calls for improved monitoring of wetlands and human changes to them. It also urges better methods of detecting different types of wetlands and different methane release rates between flooded and drained areas. The amount of atmospheric methane had remained relatively stable for about a decade, but concentrations began to rise again in 2007. Scientists assumed that wetland methane release was largest in the tropics, said Professor Turetsky. “But our analyses show that northern fens, such as those created when permafrost thaws, can have emissions comparable to warm sites in the tropics, despite their cold temperatures. That’s very important when it comes to scaling methane release at a global scale. “Not only are fens one of the strongest sources of wetland greenhouse gases, but we also know that Canadian forests and tundra underlain by permafrost are thawing and creating these kinds of high methane-producing ecosystems.”

Moisture the key

Most methane studies focus on measurements at a single site, said one of her co-authors, Narasinha Shurpali, from the University of Eastern Finland. “Our synthesis of data from a large number of observation points across the globe is unique and serves an important need.” The team showed that small temperature changes can release much more methane from wetland soils to the atmosphere than scientists had believed. Whether climate change will increase methane emissions will depend on soil moisture, said Professor Turetsky. Under warmer and wetter conditions, much more methane is likely to be emitted. If wetland soils dry out from evaporation or human drainage, though, emissions will fall – but not without other problems, like wildfires breaking out on drying peatlands. Another study co-author, Kim Wickland, of the United States Geological Survey, said: “This study provides important data for better accounting of how methane emissions change after wetland drainage and flooding.” She said emissions varied between those from natural wetlands and those from areas which had been disturbed or managed. – Climate News Network

Camels are frugal methane emitters

FOR IMMEDIATE RELEASE Some domesticated animals add appreciably to the methane which is warming the atmosphere.  But despite earlier assumptions, camels are not among them. LONDON, 10 April – Never accuse science of neglecting the smallest and apparently least significant detail in its efforts to understand fully how the Earth and all that’s in it keeps going. One of the latest arcane revelations comes from scientists in Switzerland, who describe in the Public Library of Science journal PLOS One why we should not heap blame on camels for adding to the methane already in the atmosphere. Camels – and their camelid relatives, llamas, guanacos, alpacas, vicuñas, dromedaries and Bactrian camels – do produce methane, which is more than 20 times as potent a greenhouse gas as carbon dioxide. But they produce significantly less of it than ruminants like cattle, sheep and goats. When they are digesting their food, ruminants exhale large quantities of methane, around 20% of global methane emissions. So far the assumption has been that camels, with their similar digestive systems, produce the same amount of the gas.

Smaller appetites

But now researchers at the University of Zurich and ETH Zurich have shown that camels release less methane than ruminants. Ruminants and camelids are similar but not identical: both groups have stomachs with several chambers, enabling them to regurgitate food from one chamber in order to reduce it in size by renewed chewing. That is why people had assumed till now that camelids and ruminants produce similar amounts of methane. But the researchers have concluded that in absolute terms camels release less methane than cows and sheep of comparable body size. Admittedly, it is slightly more complicated than that: if you compare methane production with the amount of what the team calls “converted feed”, then methane releases are the same in both groups. But the amount of converted feed is what matters. The research may be less esoteric than it at first appears. Working with Zurich zoo and private camel keepers, the researchers measured methane production in three types of camelids. They found that all three had a lower metabolism than ruminants – because they eat less.

Not enough meat

One of the report’s authors, Dr Marcus Clauss, a veterinary surgeon from the Vetsuisse Faculty of the University of Zurich, told the Network: “For each unit of digested food, ruminants and camelids produce the same amount of methane. “But camels generally have a lower metabolism and hence eat less than domestic ruminants. So the total amount of digested fibre per day is lower in camelids, hence the total amount of methane produced is also lower.” The authors say the camelids’ lower metabolism may be important for countries with lots of camels, like the dromedaries of the Middle East and Australia, or the alpacas and llamas of South America. But they do not advocate a switch from beef and lamb to camel meat. Dr Clauss says: “Personally, I do not think this has relevance to agricultural systems, because there are many other things to consider. For example, I am sure you could not produce the same amount of meat in the same time from a camel as you can from a steer.” – Climate News Network

FOR IMMEDIATE RELEASE Some domesticated animals add appreciably to the methane which is warming the atmosphere.  But despite earlier assumptions, camels are not among them. LONDON, 10 April – Never accuse science of neglecting the smallest and apparently least significant detail in its efforts to understand fully how the Earth and all that’s in it keeps going. One of the latest arcane revelations comes from scientists in Switzerland, who describe in the Public Library of Science journal PLOS One why we should not heap blame on camels for adding to the methane already in the atmosphere. Camels – and their camelid relatives, llamas, guanacos, alpacas, vicuñas, dromedaries and Bactrian camels – do produce methane, which is more than 20 times as potent a greenhouse gas as carbon dioxide. But they produce significantly less of it than ruminants like cattle, sheep and goats. When they are digesting their food, ruminants exhale large quantities of methane, around 20% of global methane emissions. So far the assumption has been that camels, with their similar digestive systems, produce the same amount of the gas.

Smaller appetites

But now researchers at the University of Zurich and ETH Zurich have shown that camels release less methane than ruminants. Ruminants and camelids are similar but not identical: both groups have stomachs with several chambers, enabling them to regurgitate food from one chamber in order to reduce it in size by renewed chewing. That is why people had assumed till now that camelids and ruminants produce similar amounts of methane. But the researchers have concluded that in absolute terms camels release less methane than cows and sheep of comparable body size. Admittedly, it is slightly more complicated than that: if you compare methane production with the amount of what the team calls “converted feed”, then methane releases are the same in both groups. But the amount of converted feed is what matters. The research may be less esoteric than it at first appears. Working with Zurich zoo and private camel keepers, the researchers measured methane production in three types of camelids. They found that all three had a lower metabolism than ruminants – because they eat less.

Not enough meat

One of the report’s authors, Dr Marcus Clauss, a veterinary surgeon from the Vetsuisse Faculty of the University of Zurich, told the Network: “For each unit of digested food, ruminants and camelids produce the same amount of methane. “But camels generally have a lower metabolism and hence eat less than domestic ruminants. So the total amount of digested fibre per day is lower in camelids, hence the total amount of methane produced is also lower.” The authors say the camelids’ lower metabolism may be important for countries with lots of camels, like the dromedaries of the Middle East and Australia, or the alpacas and llamas of South America. But they do not advocate a switch from beef and lamb to camel meat. Dr Clauss says: “Personally, I do not think this has relevance to agricultural systems, because there are many other things to consider. For example, I am sure you could not produce the same amount of meat in the same time from a camel as you can from a steer.” – Climate News Network

Warmer freshwater emits more methane

FOR IMMEDIATE RELEASE Scientists think the amount of methane emitted to the atmosphere from freshwater ecosystems will increase as the climate warms, triggering further warming. LONDON, 20 March – British scientists have identified yet another twist to the threat of global warming. Any further rises in temperature are likely to accelerate the release of methane from rivers, lakes, deltas, bogs, swamps, marshlands and rice paddy fields. Methane or natural gas is a greenhouse gas. Weight for weight, it is more than 20 times more potent than carbon dioxide over a century, and researchers have repeatedly examined the contribution of natural gas emitted by ruminant cattle to global warming. But Gabriel Yvon-Durocher of the University of Exeter and colleagues considered something wider: the pattern of response to temperature in those natural ecosystems that are home to microbes that release methane. They report in Nature that they looked at data from hundreds of field surveys and laboratory experiments to explore the speed at which the flow of methane increased with temperature. Microbes, algae, freshwater plants and animals are all part of an active ecosystem and take their nourishment from and return waste to the atmosphere. Healthy plants take carbon dioxide from the atmosphere with photosynthesis. Most of the methane in freshwater systems is produced by an important group of microbes called Archaea that live in waterlogged, oxygen-free sediments and play an important role in decay. Plant uptake of carbon dioxide is affected by temperature, and so is microbial methane production. Respiration also releases carbon dioxide. The questions the researchers set out to answer were: which gas is more likely to be released in greater quantities as temperatures rise? And is the outcome the same whether they examine the Archaea only, or all the microbes in an ecosystem, or the entire package of submerged freshwater life?

More heat, more methane

The answer is, the scientists say, that methane emissions go up with the mercury, and that the ratio of methane to carbon dioxide also goes up in step with temperature. And the result is the same whether you consider the microbes or the whole ecosystem. “The discovery that methane fluxes are much more responsive to temperature than the processes that produce and consume carbon dioxide highlights another mechanism by which the global carbon cycle may serve to accelerate rather than mitigate future climate change,” says Dr Yvon-Durocher. This is not the end of the story. All such studies raise as many questions as they answer, and more research is necessary. The next puzzle is how to fit such findings into models of climate change. However, the researchers feel they have cleared up one point. Dr Yvon-Durocher says: “Our research provides scientists with an important clue about the mechanisms that may control the response of methane emissions from ecosystems to global warming.” – Climate News Network

FOR IMMEDIATE RELEASE Scientists think the amount of methane emitted to the atmosphere from freshwater ecosystems will increase as the climate warms, triggering further warming. LONDON, 20 March – British scientists have identified yet another twist to the threat of global warming. Any further rises in temperature are likely to accelerate the release of methane from rivers, lakes, deltas, bogs, swamps, marshlands and rice paddy fields. Methane or natural gas is a greenhouse gas. Weight for weight, it is more than 20 times more potent than carbon dioxide over a century, and researchers have repeatedly examined the contribution of natural gas emitted by ruminant cattle to global warming. But Gabriel Yvon-Durocher of the University of Exeter and colleagues considered something wider: the pattern of response to temperature in those natural ecosystems that are home to microbes that release methane. They report in Nature that they looked at data from hundreds of field surveys and laboratory experiments to explore the speed at which the flow of methane increased with temperature. Microbes, algae, freshwater plants and animals are all part of an active ecosystem and take their nourishment from and return waste to the atmosphere. Healthy plants take carbon dioxide from the atmosphere with photosynthesis. Most of the methane in freshwater systems is produced by an important group of microbes called Archaea that live in waterlogged, oxygen-free sediments and play an important role in decay. Plant uptake of carbon dioxide is affected by temperature, and so is microbial methane production. Respiration also releases carbon dioxide. The questions the researchers set out to answer were: which gas is more likely to be released in greater quantities as temperatures rise? And is the outcome the same whether they examine the Archaea only, or all the microbes in an ecosystem, or the entire package of submerged freshwater life?

More heat, more methane

The answer is, the scientists say, that methane emissions go up with the mercury, and that the ratio of methane to carbon dioxide also goes up in step with temperature. And the result is the same whether you consider the microbes or the whole ecosystem. “The discovery that methane fluxes are much more responsive to temperature than the processes that produce and consume carbon dioxide highlights another mechanism by which the global carbon cycle may serve to accelerate rather than mitigate future climate change,” says Dr Yvon-Durocher. This is not the end of the story. All such studies raise as many questions as they answer, and more research is necessary. The next puzzle is how to fit such findings into models of climate change. However, the researchers feel they have cleared up one point. Dr Yvon-Durocher says: “Our research provides scientists with an important clue about the mechanisms that may control the response of methane emissions from ecosystems to global warming.” – Climate News Network

Low-flatulence livestock can cool planet

FOR IMMEDIATE RELEASE Farmers may be able to rear livestock which produce fewer emissions from their stomachs of methane, one of the most important greenhouse gases. LONDON, 18 January – Stand by for a new breed of farm animal – the low-methane cow. European scientists are collaborating in a bid to find a cow that makes the same milk, but manages to do so while emitting lower levels of natural gas from the ruminant stomach. Methane is a fact of farm life: cows eat grass, hay and silage, and then proceed to digest it with help from an arsenal of stomach and gut microbes. But methane is also a potent greenhouse gas (GHG): weight for weight it is more than 20 times more potent than carbon dioxide over a century. About a fifth of all GHG emissions from agriculture are directly released from the stomachs of the world’s cattle herds. And a consortium called RuminOmics has launched research into every aspect of animal husbandry in an attempt to lower the methane productivity while keeping up the dairy output. Phil Garnsworthy is a dairy scientist at the University of Nottingham, UK, and one of the project partners. He reasons that cattle vary quite dramatically in the levels of methane from their stomachs, so it would be possible to imagine a dairy herd that produced the same volume of milk while reducing their gaseous discharges. There are other factors: as every human knows too well, gas output is linked to diet. “It is possible to imagine cutting emissions from cattle by a fifth, using a combination approach in which you would breed from lower-emitting cattle as well as changing their diets”, said Professor Garnsworthy.

More profitable

Inheritance, too, may play a role. “There are three issues: diet, genetics and the microbiology of the cow’s rumen”, says Lorenzo Morelli of the Catholic University of the Sacred Heart in Piacenza, Italy. “We think that animal genetics may well influence their gut microbiology. However, this link has not been proved and we are still in the data collection phase.” Most animal husbandry research has concentrated on raising animal productivity and fertility. But lower methane output could join the list of desired characteristics. There could even be a direct pay-off for the herdsmen. “The methane is lost energy that could go into producing milk”, says Morelli. “So if we can find the right genetic mix, we can find cattle that are less polluting, more productive, and more profitable for the farmer.” Methane is a short-lived gas: it stays in the atmosphere for about 10 years. Carbon dioxide – always the dominant greenhouse gas – is released in far greater quantities, and a molecule of carbon dioxide stays in the atmosphere for about 100 years.

Multiple gains

But the same volume of methane over a 20-year period will trap 70 times the heat that carbon dioxide retains, so any serious reduction in methane output could make a significant difference to the pace of climate change. Some scientists have argued that it would be better simply to reduce the herds, rather than their digestive output. In December an international team argued in the journal Nature Climate Change that since methane was the second most abundant GHG, one of the most effective ways to cut output would be to reduce global populations of ruminant livestock – sheep, goats, camels and buffalo as well as cattle are all ruminants. Globally, they argued, the numbers of ruminant livestock had risen by 50% in the last 50 years, and now about 3.6 billion animals were grazing on about one quarter of the Earth’s land area. Furthermore, a third of all arable land was used to grow feed for these animals. “Cutting the number of ruminant livestock could have additional benefits for food security, human health and environmental conservation involving water quality, wildlife habitat and biodiversity”, said Peter Smith of the University of Aberdeen in Scotland, one of the authors. – Climate News Network

FOR IMMEDIATE RELEASE Farmers may be able to rear livestock which produce fewer emissions from their stomachs of methane, one of the most important greenhouse gases. LONDON, 18 January – Stand by for a new breed of farm animal – the low-methane cow. European scientists are collaborating in a bid to find a cow that makes the same milk, but manages to do so while emitting lower levels of natural gas from the ruminant stomach. Methane is a fact of farm life: cows eat grass, hay and silage, and then proceed to digest it with help from an arsenal of stomach and gut microbes. But methane is also a potent greenhouse gas (GHG): weight for weight it is more than 20 times more potent than carbon dioxide over a century. About a fifth of all GHG emissions from agriculture are directly released from the stomachs of the world’s cattle herds. And a consortium called RuminOmics has launched research into every aspect of animal husbandry in an attempt to lower the methane productivity while keeping up the dairy output. Phil Garnsworthy is a dairy scientist at the University of Nottingham, UK, and one of the project partners. He reasons that cattle vary quite dramatically in the levels of methane from their stomachs, so it would be possible to imagine a dairy herd that produced the same volume of milk while reducing their gaseous discharges. There are other factors: as every human knows too well, gas output is linked to diet. “It is possible to imagine cutting emissions from cattle by a fifth, using a combination approach in which you would breed from lower-emitting cattle as well as changing their diets”, said Professor Garnsworthy.

More profitable

Inheritance, too, may play a role. “There are three issues: diet, genetics and the microbiology of the cow’s rumen”, says Lorenzo Morelli of the Catholic University of the Sacred Heart in Piacenza, Italy. “We think that animal genetics may well influence their gut microbiology. However, this link has not been proved and we are still in the data collection phase.” Most animal husbandry research has concentrated on raising animal productivity and fertility. But lower methane output could join the list of desired characteristics. There could even be a direct pay-off for the herdsmen. “The methane is lost energy that could go into producing milk”, says Morelli. “So if we can find the right genetic mix, we can find cattle that are less polluting, more productive, and more profitable for the farmer.” Methane is a short-lived gas: it stays in the atmosphere for about 10 years. Carbon dioxide – always the dominant greenhouse gas – is released in far greater quantities, and a molecule of carbon dioxide stays in the atmosphere for about 100 years.

Multiple gains

But the same volume of methane over a 20-year period will trap 70 times the heat that carbon dioxide retains, so any serious reduction in methane output could make a significant difference to the pace of climate change. Some scientists have argued that it would be better simply to reduce the herds, rather than their digestive output. In December an international team argued in the journal Nature Climate Change that since methane was the second most abundant GHG, one of the most effective ways to cut output would be to reduce global populations of ruminant livestock – sheep, goats, camels and buffalo as well as cattle are all ruminants. Globally, they argued, the numbers of ruminant livestock had risen by 50% in the last 50 years, and now about 3.6 billion animals were grazing on about one quarter of the Earth’s land area. Furthermore, a third of all arable land was used to grow feed for these animals. “Cutting the number of ruminant livestock could have additional benefits for food security, human health and environmental conservation involving water quality, wildlife habitat and biodiversity”, said Peter Smith of the University of Aberdeen in Scotland, one of the authors. – Climate News Network