Tag Archives: Aviation

Supply chains generate massive carbon emissions

When it comes to cutting carbon emissions, think global. Think multinational. Think Coca-Cola, or Total. But don’t fly.

LONDON, 25 September, 2020 – Chinese and European researchers have identified the source of almost one-fifth of all the world’s carbon emissions. They come from the supply chains of giant multinational companies.

Not only does global business export investment, it exports carbon dioxide emissions as well. And the big players play it really big.

The US business Walmart, the world’s biggest retailer, with 11,500 stores in 28 countries, in 2016 generated more emissions abroad than the whole of Germany’s foreign-owned retail sector.

That year Coca-Cola’s global emissions matched those from the entire foreign food-and-drink industry in China. Total SA’s foreign affiliates generated more than a tenth of the total emissions of France. Altogether, the multinational giants accounted for 18.7% of global emissions.

By contrast, and to provide perspective, the entire global aviation industry contributes just 3.5% of the forces that drive climate change – and that includes the impact of condensation trails and soot and sulphur exhausts as well as carbon dioxide emissions.

“If the world’s leading companies exercised leadership on climate change they could have a transformative effect on global efforts to reduce emissions”

In fact, in eight decades, the aviation industry’s total carbon dioxide discharges add up to only 1.5% of all humankind’s total carbon emissions up to 2018, according to British researchers.

These two very different studies illuminate the great challenge of climate change: it’s not enough for a country to claim it has reduced its carbon footprint, if its big achievement has been to export the burden of emissions to a labour force somewhere else.

And it’s not enough to measure just carbon dioxide. Tomorrow’s planners, investors, economists, designers and engineers must also think about the whole package of anthropogenic change that has begun to raise the planetary temperature to dangerous levels. And in each case the message is the same: think of it as a transnational challenge.

“Multinational companies have enormous influence stretching far beyond national borders,” said Dabo Guan of University College London. “If the world’s leading companies exercised leadership on climate change – for instance by requiring energy efficiency in their supply chains – they could have a transformative effect on global efforts to reduce emissions.”

Outsourced responsibility

Professor Guan and colleagues from Beijing and Norway report in the journal Nature Climate Change that they looked for a new way to measure the impact of big business.

They followed the money. They found that when investment flowed from developed to developing countries, those businesses were also outsourcing the responsibility for carbon emissions. So a fair way of accounting carbon responsibility would be to return it to the investor nation.

For example in 2011, US investment in India resulted in emissions of more than 43 million tonnes. By 2016, this figure had passed more than 70 million tonnes. In 2011, emissions from multinational investment stood at 22% of all emissions worldwide. By 2016 this figure had fallen to 18.7% – partly because of improvements in energy efficiency, and partly because of a fall in foreign investment.

Although carbon dioxide emissions have become a standard measure for potential climate change, they are only part of the story. The climate damage from a jet flight is more than just the greenhouse gas from burning high-octane fuel.

New analysis in the journal Atmospheric Environment confirms that aviation’s biggest contribution to global warming is the effects on clouds: cirrus condensation trails formed by the almost-explosive growth in air traffic reflect and trap heat escaping from the atmosphere on a massive scale.

International flights exempted

The discharge of water vapour, soot and sulphate particles from the engines is also part of what the researchers call “effective radiative forcing,” or ERF.

And when these aspects are factored in, it seems that aviation on a global scale adds up to 3.5% of all human activities that drive climate change. The Paris Agreement on climate change – a global resolve to contain global heating by 2100 to “well below” 2°C above the norm for most of human history – includes domestic aviation within national targets to reduce emissions.

But it does not address international aviation, which adds up to 64% of all air traffic.

“The new study means that aviation’s impact on climate change can be compared with other sectors such as maritime shipping, ground transportation and energy generation, as it has a consistent set of ERF measurements,” said David Lee, of Manchester Metropolitan University, who led the research. – Climate News Network

When it comes to cutting carbon emissions, think global. Think multinational. Think Coca-Cola, or Total. But don’t fly.

LONDON, 25 September, 2020 – Chinese and European researchers have identified the source of almost one-fifth of all the world’s carbon emissions. They come from the supply chains of giant multinational companies.

Not only does global business export investment, it exports carbon dioxide emissions as well. And the big players play it really big.

The US business Walmart, the world’s biggest retailer, with 11,500 stores in 28 countries, in 2016 generated more emissions abroad than the whole of Germany’s foreign-owned retail sector.

That year Coca-Cola’s global emissions matched those from the entire foreign food-and-drink industry in China. Total SA’s foreign affiliates generated more than a tenth of the total emissions of France. Altogether, the multinational giants accounted for 18.7% of global emissions.

By contrast, and to provide perspective, the entire global aviation industry contributes just 3.5% of the forces that drive climate change – and that includes the impact of condensation trails and soot and sulphur exhausts as well as carbon dioxide emissions.

“If the world’s leading companies exercised leadership on climate change they could have a transformative effect on global efforts to reduce emissions”

In fact, in eight decades, the aviation industry’s total carbon dioxide discharges add up to only 1.5% of all humankind’s total carbon emissions up to 2018, according to British researchers.

These two very different studies illuminate the great challenge of climate change: it’s not enough for a country to claim it has reduced its carbon footprint, if its big achievement has been to export the burden of emissions to a labour force somewhere else.

And it’s not enough to measure just carbon dioxide. Tomorrow’s planners, investors, economists, designers and engineers must also think about the whole package of anthropogenic change that has begun to raise the planetary temperature to dangerous levels. And in each case the message is the same: think of it as a transnational challenge.

“Multinational companies have enormous influence stretching far beyond national borders,” said Dabo Guan of University College London. “If the world’s leading companies exercised leadership on climate change – for instance by requiring energy efficiency in their supply chains – they could have a transformative effect on global efforts to reduce emissions.”

Outsourced responsibility

Professor Guan and colleagues from Beijing and Norway report in the journal Nature Climate Change that they looked for a new way to measure the impact of big business.

They followed the money. They found that when investment flowed from developed to developing countries, those businesses were also outsourcing the responsibility for carbon emissions. So a fair way of accounting carbon responsibility would be to return it to the investor nation.

For example in 2011, US investment in India resulted in emissions of more than 43 million tonnes. By 2016, this figure had passed more than 70 million tonnes. In 2011, emissions from multinational investment stood at 22% of all emissions worldwide. By 2016 this figure had fallen to 18.7% – partly because of improvements in energy efficiency, and partly because of a fall in foreign investment.

Although carbon dioxide emissions have become a standard measure for potential climate change, they are only part of the story. The climate damage from a jet flight is more than just the greenhouse gas from burning high-octane fuel.

New analysis in the journal Atmospheric Environment confirms that aviation’s biggest contribution to global warming is the effects on clouds: cirrus condensation trails formed by the almost-explosive growth in air traffic reflect and trap heat escaping from the atmosphere on a massive scale.

International flights exempted

The discharge of water vapour, soot and sulphate particles from the engines is also part of what the researchers call “effective radiative forcing,” or ERF.

And when these aspects are factored in, it seems that aviation on a global scale adds up to 3.5% of all human activities that drive climate change. The Paris Agreement on climate change – a global resolve to contain global heating by 2100 to “well below” 2°C above the norm for most of human history – includes domestic aviation within national targets to reduce emissions.

But it does not address international aviation, which adds up to 64% of all air traffic.

“The new study means that aviation’s impact on climate change can be compared with other sectors such as maritime shipping, ground transportation and energy generation, as it has a consistent set of ERF measurements,” said David Lee, of Manchester Metropolitan University, who led the research. – Climate News Network

Carbon-neutral aircraft might work with ion drive

Ion drive works in outer space. Just possibly, plasma power could fill the skies with carbon-neutral aircraft.

LONDON, 10 June, 2020 − Chinese engineers may have designed the basis for the first carbon-neutral aircraft, perhaps a commercial jet airliner powered entirely by very hot air through an ion drive. If it works on that scale, there would be no high-octane aviation spirit, no greenhouse gas emissions and no contribution to long-term global warming.

Nor would such planes be fuelled by anything defined as ordinary matter. The driving force that delivers the thrust and overcomes gravitational pull and air friction would be plasma, the fourth state of matter, and the power source of the sun and all the stars.

Think of a jet stream of ionised atoms − dismantled atomic particles − roaring through the engines to take the vehicle to take-off speeds. That’s the ambition.

Right now, according to scientists at Wuhan University, writing in the American Institute of Physics journal AIP Advances, what they have is a propulsion thruster that utilises air plasma induced by microwave ionisation. It would simply need air and electricity to produce high temperature and pressurised plasma.

They have already assembled an experimental apparatus and used it to lift a one kilogram steel ball over a 24mm-diameter quartz tube, at half a litre per second of airflow at 400 watts to produce just 10 newtons of thrust.

“A carbon emission-free thruster could potentially be used as a jet thruster in the atmosphere”

A newton is a unit of force that will accelerate one kg of mass at one metre per second, every second. The Wuhan achievement, they say, corresponds to a jet pressure of 24,000 newtons per square metre,

That is: with higher microwave power or greater airflow, they could achieve propulsion forces and jet pressures of the kind seen every minute of every day at commercial airports.

The journey from the laboratory equipment now – a one kilowatt magnetron, a circulator, a flattened wave guide, an igniter and a quartz tube – to a set of jet engines that can carry hundreds of passengers across half the world with complete confidence is going to be a long one: right now, the experiment is an indicator simply of the astonishing ingenuity being displayed in laboratories in Asia, Europe and America to find ways of reducing dependence on fossil fuels.

And aircraft – and particularly jet aircraft – present almost intractable challenges. Until now, no tested power source other than high-quality liquid fossil fuel can deliver what is needed to fly very heavy aircraft to the upper reaches of the atmosphere.

Rocket needed first

Relatively light all-electric planes with a short range are being tested now.  The US Space Agency Nasa has already deployed plasma power – science fiction fans have long known it as ion drive – in spacecraft, but at the low thrust levels needed to change the course of a spacecraft already in very high orbit and far from the planet’s gravitational drag.

But these first space probes had to be lifted into high orbit aboard a rocket. A team at Massachusetts Institute of Technology has tested, using a different approach, a plasma-powered glider: it flew 55 metres in 12 seconds before touching down again. But the driving force would never be enough to lift a cargo or passenger plane.

Swiss scientists have explored the idea of a solar-powered plane: in effect
however this would deploy solar energy to split carbon dioxide and water and turn them into synthetic natural gas.

The Wuhan experiment has the potential for a much bigger force. For the moment, that is all it has: potential. The researchers call their prototype “a home-made device”, and they add: “Given the same power consumption, its propulsion pressure is comparable to that of conventional airplane jet engines using fossil fuels.

“Therefore, such a carbon-emission free thruster could potentially be used as a jet thruster in the atmosphere.” − Climate News Network

Ion drive works in outer space. Just possibly, plasma power could fill the skies with carbon-neutral aircraft.

LONDON, 10 June, 2020 − Chinese engineers may have designed the basis for the first carbon-neutral aircraft, perhaps a commercial jet airliner powered entirely by very hot air through an ion drive. If it works on that scale, there would be no high-octane aviation spirit, no greenhouse gas emissions and no contribution to long-term global warming.

Nor would such planes be fuelled by anything defined as ordinary matter. The driving force that delivers the thrust and overcomes gravitational pull and air friction would be plasma, the fourth state of matter, and the power source of the sun and all the stars.

Think of a jet stream of ionised atoms − dismantled atomic particles − roaring through the engines to take the vehicle to take-off speeds. That’s the ambition.

Right now, according to scientists at Wuhan University, writing in the American Institute of Physics journal AIP Advances, what they have is a propulsion thruster that utilises air plasma induced by microwave ionisation. It would simply need air and electricity to produce high temperature and pressurised plasma.

They have already assembled an experimental apparatus and used it to lift a one kilogram steel ball over a 24mm-diameter quartz tube, at half a litre per second of airflow at 400 watts to produce just 10 newtons of thrust.

“A carbon emission-free thruster could potentially be used as a jet thruster in the atmosphere”

A newton is a unit of force that will accelerate one kg of mass at one metre per second, every second. The Wuhan achievement, they say, corresponds to a jet pressure of 24,000 newtons per square metre,

That is: with higher microwave power or greater airflow, they could achieve propulsion forces and jet pressures of the kind seen every minute of every day at commercial airports.

The journey from the laboratory equipment now – a one kilowatt magnetron, a circulator, a flattened wave guide, an igniter and a quartz tube – to a set of jet engines that can carry hundreds of passengers across half the world with complete confidence is going to be a long one: right now, the experiment is an indicator simply of the astonishing ingenuity being displayed in laboratories in Asia, Europe and America to find ways of reducing dependence on fossil fuels.

And aircraft – and particularly jet aircraft – present almost intractable challenges. Until now, no tested power source other than high-quality liquid fossil fuel can deliver what is needed to fly very heavy aircraft to the upper reaches of the atmosphere.

Rocket needed first

Relatively light all-electric planes with a short range are being tested now.  The US Space Agency Nasa has already deployed plasma power – science fiction fans have long known it as ion drive – in spacecraft, but at the low thrust levels needed to change the course of a spacecraft already in very high orbit and far from the planet’s gravitational drag.

But these first space probes had to be lifted into high orbit aboard a rocket. A team at Massachusetts Institute of Technology has tested, using a different approach, a plasma-powered glider: it flew 55 metres in 12 seconds before touching down again. But the driving force would never be enough to lift a cargo or passenger plane.

Swiss scientists have explored the idea of a solar-powered plane: in effect
however this would deploy solar energy to split carbon dioxide and water and turn them into synthetic natural gas.

The Wuhan experiment has the potential for a much bigger force. For the moment, that is all it has: potential. The researchers call their prototype “a home-made device”, and they add: “Given the same power consumption, its propulsion pressure is comparable to that of conventional airplane jet engines using fossil fuels.

“Therefore, such a carbon-emission free thruster could potentially be used as a jet thruster in the atmosphere.” − Climate News Network

UK airports must shut to reach 2050 climate target

All UK airports must close by 2050 for the country to reach its target of net zero climate emissions by then, scientists say.

LONDON, 18 February, 2020 − If it is to achieve its target of net zero climate emissions by 2050, all UK airports must close by mid-century and the country will have to make other drastic and fundamental lifestyle changes, says a report from a research group backed by the government in London.

With the UK due to host this year’s round of crucial UN climate talks in Glasgow in November, a group of academics has embarrassed the British government by showing it has currently no chance of meeting its own legally binding target to reduce greenhouse gas emissions to nothing within 30 years.

Their report, Absolute Zero, published by the University of Cambridge, says no amount of government or public wishful thinking will hide the fact that the country will not reach zero emissions by 2050 without barely conceivable changes to policies, industrial processes and lifestyles. Its authors include colleagues from five other British universities.

All are members of a group from UK Fires, a research programme sponsored by the UK government, aiming to support a 20% cut in the country’s true emissions by 2050 by placing resource efficiency at the heart of its future industrial strategy. The report was paid for under the UK Fires programme.

As well as a temporary halt to flying, the report also says British people cannot go on driving heavier cars and turning up the heating in their homes.

“The UK is responsible for all emissions caused by its purchasing, including imported goods, international flights and shipping”

The government, industry and the public, it says, cannot continue to indulge themselves in these ways in the belief that new technologies will somehow save them – everyone will have to work together change their way of life.

Because electric or zero-emission aircraft cannot be developed in time, most British airports will need to close by the end of this decade, and all flying will have to stop by 2050 until non-polluting versions are available.

Electrification of surface transport, rail and road, needs to be rapid, with the phasing out of all development of petrol and diesel cars immediately. Even if all private cars are electric, the amount of traffic will have to fall to 60% of 2020 levels by 2050, and all cars will have to be smaller.

The report also suggests that ships, currently heavy users of fossil fuels, need to convert to electric propulsion in order to allow for necessary imports and exports.

Not enough time

The reasoning behind the report is that technologies to cut greenhouse gas emissions, like carbon capture and storage, will not be developed in time and on a large enough scale to make a difference to emission reductions by 2050.

Nor is it any use exporting energy-intensive industries like steel-making, because the emissions will still take place abroad.

Instead, homegrown industries need to be developed that use no fossil fuels but are powered by electricity. The report says blast furnaces need to be phased out and replaced by existing technologies that recycle steel using renewable electricity.

It calls for public debate and discussion about the lifestyle changes that will be essential. Although such luxuries as flying away on holiday and driving large cars will have to be foregone, and eating beef and lamb curtailed, the scientists say that life could be just as rich as today.

They say: “… sports, social life, eating, hobbies, games, computing, reading, TV, music, radio, volunteering (and sleeping!) We can all do more of these without any impact on emissions”.

Offsets won’t work

They want the public to help by lobbying for airport closures, more trains, no new roads and more renewable electricity.

The report insists that the government should not try to hide any of its emissions by importing goods: “The UK is responsible for all emissions caused by its purchasing, including imported goods, international flights and shipping.”

Nor can there be any meaningful “carbon offsets.” The only short-term option we have of reducing emissions – at least by 2050 – is to plant trees. “Even a massive increase in forestry would only have a small effect compared to today’s emissions.”

The authors comment: “There are no invisible solutions to climate change. We urgently need to engage everyone in the process of delivering the changes that will lead to zero emissions.” − Climate News Network

All UK airports must close by 2050 for the country to reach its target of net zero climate emissions by then, scientists say.

LONDON, 18 February, 2020 − If it is to achieve its target of net zero climate emissions by 2050, all UK airports must close by mid-century and the country will have to make other drastic and fundamental lifestyle changes, says a report from a research group backed by the government in London.

With the UK due to host this year’s round of crucial UN climate talks in Glasgow in November, a group of academics has embarrassed the British government by showing it has currently no chance of meeting its own legally binding target to reduce greenhouse gas emissions to nothing within 30 years.

Their report, Absolute Zero, published by the University of Cambridge, says no amount of government or public wishful thinking will hide the fact that the country will not reach zero emissions by 2050 without barely conceivable changes to policies, industrial processes and lifestyles. Its authors include colleagues from five other British universities.

All are members of a group from UK Fires, a research programme sponsored by the UK government, aiming to support a 20% cut in the country’s true emissions by 2050 by placing resource efficiency at the heart of its future industrial strategy. The report was paid for under the UK Fires programme.

As well as a temporary halt to flying, the report also says British people cannot go on driving heavier cars and turning up the heating in their homes.

“The UK is responsible for all emissions caused by its purchasing, including imported goods, international flights and shipping”

The government, industry and the public, it says, cannot continue to indulge themselves in these ways in the belief that new technologies will somehow save them – everyone will have to work together change their way of life.

Because electric or zero-emission aircraft cannot be developed in time, most British airports will need to close by the end of this decade, and all flying will have to stop by 2050 until non-polluting versions are available.

Electrification of surface transport, rail and road, needs to be rapid, with the phasing out of all development of petrol and diesel cars immediately. Even if all private cars are electric, the amount of traffic will have to fall to 60% of 2020 levels by 2050, and all cars will have to be smaller.

The report also suggests that ships, currently heavy users of fossil fuels, need to convert to electric propulsion in order to allow for necessary imports and exports.

Not enough time

The reasoning behind the report is that technologies to cut greenhouse gas emissions, like carbon capture and storage, will not be developed in time and on a large enough scale to make a difference to emission reductions by 2050.

Nor is it any use exporting energy-intensive industries like steel-making, because the emissions will still take place abroad.

Instead, homegrown industries need to be developed that use no fossil fuels but are powered by electricity. The report says blast furnaces need to be phased out and replaced by existing technologies that recycle steel using renewable electricity.

It calls for public debate and discussion about the lifestyle changes that will be essential. Although such luxuries as flying away on holiday and driving large cars will have to be foregone, and eating beef and lamb curtailed, the scientists say that life could be just as rich as today.

They say: “… sports, social life, eating, hobbies, games, computing, reading, TV, music, radio, volunteering (and sleeping!) We can all do more of these without any impact on emissions”.

Offsets won’t work

They want the public to help by lobbying for airport closures, more trains, no new roads and more renewable electricity.

The report insists that the government should not try to hide any of its emissions by importing goods: “The UK is responsible for all emissions caused by its purchasing, including imported goods, international flights and shipping.”

Nor can there be any meaningful “carbon offsets.” The only short-term option we have of reducing emissions – at least by 2050 – is to plant trees. “Even a massive increase in forestry would only have a small effect compared to today’s emissions.”

The authors comment: “There are no invisible solutions to climate change. We urgently need to engage everyone in the process of delivering the changes that will lead to zero emissions.” − Climate News Network

Flight paths are set to get bumpier

FOR IMMEDIATE RELEASE As growing carbon dioxide emissions continue to warm the climate, more aircraft are likely to encounter turbulence in flight, meaning bumpier and perhaps longer journeys for passengers, scientists say. LONDON, 9 April – Airline passengers – and airlines too – could be in for a rough ride as the decades pass and the world warms. Two British scientists have asked the question literally uppermost in the minds of transatlantic flight planners: what difference will global warming make to atmospheric turbulence? Clear air turbulence is an enduring problem for commercial aircraft: pilots cannot see it coming, it doesn’t reflect signals to onboard radar, and satellite monitors cannot detect it. Pilots however encounter moderate or uncomfortable clear air turbulence at least one per cent of cruise time. This adds up to tens of thousands of bumpy episodes each year, and hundreds of passengers who didn’t fasten their seatbelts in time may be injured. Clear air turbulence is calculated to cost airlines £100 million ($150 million) a year in delays and damage, and although air crew and passengers have been facing such discomforts almost since the invention of flight 110 years ago, the mechanisms of turbulence are still, in that famously enigmatic scientific phrase, “not fully understood.” But Paul Williams of the University of Reading and Manoj Joshi of the University of East Anglia report in Nature Climate Change that they decided to look at computer models to see whether climate change would make a difference. Turbulence is linked to atmospheric jet streams and these are likely to be strengthened by man-made global warming. Since, right now, climate scientists cannot predict episodes of turbulence in particular latitudes at identifiable altitudes, the researchers could reach only very general conclusions.

“Aviation is partly responsible for changing the climate in the first place”

And since the factors involved in churning up flows of air are the subject of serious academic debate, they had a lot of possibilities to consider and at least 20 different units of measurement to factor into their models – technicalities like the magnitude of vertical shear of horizontal wind, flow deformation and simple wind speed, and highly specialised meteorological considerations such as the negative Richardson number, and the Brown energy dissipation rate. They also had to consider the air traffic lanes between Europe and the Americas, the changes according to season, and the projected rates of increase in carbon dioxide emissions into the atmosphere. They decided to focus on the case for winter flights, because that is when turbulence is at its peak. They found that at typical cruise altitudes in the northern half of the North Atlantic corridor in winter, most of their diagnostics showed between 10% and 40% increase in median strength of turbulence, and a 40% to 170% increase in the frequency of episodes of moderate or greater turbulence. So the airplanes that significantly increase the potential for global warming will also be affected by global warming. “We conclude that climate change will lead to bumpier transatlantic flights by the middle of this century, assuming the same flight tracks are used”, they report. “Observational evidence suggests that this increase in bumpiness has already begun. “Flight paths may need to become more convoluted to avoid patches of turbulence that are stronger and more frequent, in which case journey times will lengthen and fuel consumption and emissions will increase, in the same season and location that contrails have their largest climatic impact.” Finally, they say, any increase in clear air turbulence would have important implications for large-scale atmospheric circulation, because clear air turbulence contributes significantly to exchanges between the stratosphere and the lower atmosphere. “Aviation is partly responsible for changing the climate in the first place”, said Dr Williams. “It is ironic that the climate looks set to exact its revenge by creating a more turbulent atmosphere for flying.” – Climate News Network

FOR IMMEDIATE RELEASE As growing carbon dioxide emissions continue to warm the climate, more aircraft are likely to encounter turbulence in flight, meaning bumpier and perhaps longer journeys for passengers, scientists say. LONDON, 9 April – Airline passengers – and airlines too – could be in for a rough ride as the decades pass and the world warms. Two British scientists have asked the question literally uppermost in the minds of transatlantic flight planners: what difference will global warming make to atmospheric turbulence? Clear air turbulence is an enduring problem for commercial aircraft: pilots cannot see it coming, it doesn’t reflect signals to onboard radar, and satellite monitors cannot detect it. Pilots however encounter moderate or uncomfortable clear air turbulence at least one per cent of cruise time. This adds up to tens of thousands of bumpy episodes each year, and hundreds of passengers who didn’t fasten their seatbelts in time may be injured. Clear air turbulence is calculated to cost airlines £100 million ($150 million) a year in delays and damage, and although air crew and passengers have been facing such discomforts almost since the invention of flight 110 years ago, the mechanisms of turbulence are still, in that famously enigmatic scientific phrase, “not fully understood.” But Paul Williams of the University of Reading and Manoj Joshi of the University of East Anglia report in Nature Climate Change that they decided to look at computer models to see whether climate change would make a difference. Turbulence is linked to atmospheric jet streams and these are likely to be strengthened by man-made global warming. Since, right now, climate scientists cannot predict episodes of turbulence in particular latitudes at identifiable altitudes, the researchers could reach only very general conclusions.

“Aviation is partly responsible for changing the climate in the first place”

And since the factors involved in churning up flows of air are the subject of serious academic debate, they had a lot of possibilities to consider and at least 20 different units of measurement to factor into their models – technicalities like the magnitude of vertical shear of horizontal wind, flow deformation and simple wind speed, and highly specialised meteorological considerations such as the negative Richardson number, and the Brown energy dissipation rate. They also had to consider the air traffic lanes between Europe and the Americas, the changes according to season, and the projected rates of increase in carbon dioxide emissions into the atmosphere. They decided to focus on the case for winter flights, because that is when turbulence is at its peak. They found that at typical cruise altitudes in the northern half of the North Atlantic corridor in winter, most of their diagnostics showed between 10% and 40% increase in median strength of turbulence, and a 40% to 170% increase in the frequency of episodes of moderate or greater turbulence. So the airplanes that significantly increase the potential for global warming will also be affected by global warming. “We conclude that climate change will lead to bumpier transatlantic flights by the middle of this century, assuming the same flight tracks are used”, they report. “Observational evidence suggests that this increase in bumpiness has already begun. “Flight paths may need to become more convoluted to avoid patches of turbulence that are stronger and more frequent, in which case journey times will lengthen and fuel consumption and emissions will increase, in the same season and location that contrails have their largest climatic impact.” Finally, they say, any increase in clear air turbulence would have important implications for large-scale atmospheric circulation, because clear air turbulence contributes significantly to exchanges between the stratosphere and the lower atmosphere. “Aviation is partly responsible for changing the climate in the first place”, said Dr Williams. “It is ironic that the climate looks set to exact its revenge by creating a more turbulent atmosphere for flying.” – Climate News Network