Tag: flying

Why the aviation industry must look beyond carbon to get serious about climate change

Posted on by janet.crompton

 

Flying is responsible for around 5% of human-induced climate change.
Wichudapa/Shutterstock

Commercial aviation has become a cornerstone of our economy and society. It allows us to rapidly transport goods and people across the globe, facilitates over a third of all global trade by value, and supports 87.7 million jobs worldwide. However, the 80-tonne flying machines we see hurtling through our skies at near supersonic speeds also carry some serious environmental baggage.

My team’s recent review paper highlights some promising solutions the aviation industry could put in place now to reduce the harm flying does to our planet. Simply changing the routes we fly could hold the key to drastic reductions in climate impact.

Modern aeroplanes burn kerosene to generate the forward propulsion needed to overcome drag and produce lift. Kerosene is a fossil fuel with excellent energy density, providing lots of energy per kilogram burnt. But when it is burnt, harmful chemicals are released: mainly carbon dioxide (CO₂), nitrogen oxides (NOₓ), water vapour and particulate matter (tiny particles of soot, dirt and liquids).

Aviation is widely known for its carbon footprint, with the industry contributing 2.5% to the global CO₂ burden. While some may argue that this pales in comparison with other sectors, carbon is only responsible for a third of aviation’s full climate impact. Non-CO₂ emissions (mainly NOₓ and ice trails made from aircraft water vapour) make up the remaining two-thirds.

Taking all aircraft emissions into account, flying is responsible for around 5% of human-induced climate change. Given that 89% of the population has never flown, passenger demand is doubling every 20 years, and other sectors are decarbonising much faster, this number is predicted to skyrocket.

Aircraft contrails don’t last long but have a huge impact.
Daniel Ciucci/Unsplash

It’s not just carbon

Aircraft spend most of their time flying at cruise altitude (33,000 to 42,000 ft) where the air is thin, to minimise drag.

At these altitudes, aircraft NOₓ reacts with chemicals in the atmosphere to produce ozone and destroy methane, two very potent greenhouse gases. This aviation-induced ozone is not to be confused with the natural ozone layer, which occurs much higher up and protects the Earth from harmful UV rays. Unfortunately, aircraft NOₓ emissions cause more warming due to ozone production than they do cooling due to methane reduction. This leads to a net warming effect that makes up 16% of aviation’s total climate impact.

Also, when temperatures dip below -40℃ and the air is humid, aircraft water vapour condenses on particles in the exhaust and freezes. This forms an ice cloud known as a contrail. Contrails may be made of ice, but they warm the climate as they trap heat emitted from the Earth’s surface. Despite only lasting a few hours, contrails are responsible for 51% of the aviation industry’s climate warming. This means they warm the planet more than all aircraft carbon emissions that have accumulated since the dawn of powered flight.

Unlike carbon, non-CO₂ emissions cause warming through interactions with the surrounding air. Their climate impact changes depending on atmospheric conditions at the time and location of release.

Cutting non-CO₂ climate impact

Two of the most promising short-term options are climate-optimal routing and formation flight.

Left: Climate optimal routing. Right: Formation flight concept.

Climate-optimal routing involves re-routing aircraft to avoid regions of the atmosphere that are particularly climate-sensitive – for example, where particularly humid air causes long-lived and damaging contrails to form. Research shows that for a small increase in flight distance (usually no more than 1-2% of the journey), the net climate impact of a flight can be reduced by around 20%.

Flight operators can also reduce the impact of their aircraft by flying in formation, with one aircraft flying 1-2 km behind the other. The follower aircraft “surfs” the lead aircraft’s wake, leading to a 5% reduction in both CO₂ and other harmful emissions.

But flying in formation can reduce non-CO₂ warming too. When aircraft exhaust plumes overlap, the emissions within them accumulate. When NOₓ reaches a certain concentration, the rate of ozone production decreases and the warming effect slows.

And when contrails form, they grow by absorbing the surrounding water vapour. In formation flight, the aircraft’s contrails compete for water vapour, making them smaller. Summing all three reductions, formation flight could slash climate impact by up to 24%.

Decarbonising aviation will take time

The aviation industry has fixated on tackling carbon emissions. However, current plans for the industry to reach net zero by 2050 rely on an ambitious 3,000-4,000 times increase in sustainable aviation fuel (SAF) production, problematic carbon offsetting schemes, and the introduction of hydrogen- and electric-powered aircraft. All of these could take several decades to make a difference, so it’s crucial the industry cuts its environmental footprint in the meantime.

Climate-optimal routing and formation flight are two key examples of how we could make change happen faster, compared with a purely carbon-focused approach. But there is currently no political or financial incentive to change tack. It is time governments and the aviation industry start listening to the science, and take aircraft non-CO₂ emissions seriously.The Conversation

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This blog is written by Cabot Institute for the Environment member Kieran Tait, PhD Candidate in Aerospace Engineering, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Kieran Tait

 

 

Airport towns like Luton and Hounslow are suffering as people fly less often – here’s how to help them

Posted on by janet.crompton
Thousands of aircraft were grounded during the pandemic. Now research is showing people might fly less.
JetKat/Shutterstock

Tens of thousands of aircraft have been grounded for well over a year due to the pandemic. In April 2020 air travel around the world was cut by 94% from April 2019. By June 2021 it was still 60% down on June 2019 thanks to holidays being cancelled, work trips shelved, and long-planned journeys to see family and friends moved to another time.

Never has any global industry collapsed with such speed. In climate terms, this has been a cause for celebration. It has represented a chance for reducing emissions that contribute significantly to climate change and pollute our air.

Some people who live close to an airport may also have welcomed the drop in noise. But many others will be worrying about the effect the long-term reduction in air travel may have on their community’s economy.

Will the industry bounce back?

Industrial bodies estimate that it might take five years for passenger demand to return to pre-pandemic levels. That’s a longer expected recovery than any other mode of transport. Globally, an estimated 46 million jobs have been deemed at risk. This isn’t just pilots or cabin crew; it’s also those who screen your baggage or make your lunch.

But will the air industry even bounce back in five years? Research our team conducted in early 2021 in Bristol, an English city with an airport and a century-old aviation industry, found that close to 60% of those surveyed expect to fly less in the future. Many of our respondents gave climate change and the pandemic as equally important reasons. Other polling has shown that many elsewhere remain wary of flying in the future too.

Businesses may also operate differently. Polling has found that four in ten business travellers are likely to fly less in the future. Business-class seats are an important part of airline income – on some flights corporate travel can represent 75% of revenue.

Setting aside ideas about electric planes for now, it seems obvious that we will need to fly less to move to a zero-carbon economy. Two-thirds of people want a post-pandemic economic recovery to prioritise climate change. This means fewer planes, and fewer jobs for crew and baggage handlers and so on.

Rebuilding communities

The decline of older industries such as mining, textiles or pottery resulted in high unemployment in towns which were massively dependent on one of them. We are all familiar with how the closure of a local pit or car plant caused the decline of once vibrant towns, leaving a generation to struggle with unemployment and the need to retrain.

Steel mills were nestled deep in the fabric of nearby communities. Their closure removed the pivot around which lives, work and leisure were based. So with the pandemic, whole communities are at risk of a similar economic decline.

In summer 2020 the rate of those jobless (be it unemployed or on furlough) was higher in areas near UK airports. In Hounslow (near London Heathrow) this was 40% of the population – with an estimated £1 billion loss to the borough’s economy. At Gatwick airport in 2020, there were job losses for 40% of its workforce, many of whom live in nearby towns such as Crawley.

Hounslow in west London
Towns like Hounslow are highly dependent on the nearby airport for employment.
BasPhoto/Shutterstock

Many towns and communities are economically dependent on nearby airports. Luton Airport is estimated to have sustained over 27,000 jobs (directly and indirectly) and is a major employer in the region. The decline of the sector has broader effects on subsidiary industries too, such as taxis, maintenance, catering and hotels.

So what is to be done? The Green Jobs Taskforce, an industry and government initiative set up in 2020 to look at future employment, has called on the UK government to invest in jobs related to wind turbines, electric trains and replacing gas boilers.

Any version of a green new deal is necessarily a job-heavy economy, with a great deal of work needed to alter the infrastructure that powers our current lifestyle. The UK government’s Ten Point Plan for Green Industrial Revolution pledges 250,000 green jobs. The political question here is whether politicians and policymakers will be brave enough to resist a bounce back for aviation and invest in a longer term future for these airport towns, to avoid them suffering a decade of decline.

This is likely to see aviation jobs lost, and will require very targeted support for cities or regions reliant on airport employment. To build back better, a green recovery must seek to support these communities and provide them with new opportunities and livelihoods.The Conversation

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This blog was written by Cabot Institute for the Environment members Dr Ed Atkins, Lecturer, School of Geographical Sciences, University of Bristol and Professor Martin Parker, Professor of Organisation Studies, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Martin Parker
Ed Atkins

An insight into aviation emissions and their impact on the atmosphere

Posted on by janet.crompton
Image credit: El Ronzo, Flickr

The proliferation of aviation has brought about huge benefits to our society, enhancing global economic prosperity and allowing humanity to travel faster, further and more frequently than ever before. However, the relentless expansion of the industry is a major detriment to the environment on a local, regional and global level. This is due to the vast amounts of pollution produced from the jet fuel combustion process, that is required to propel aircraft through the air and to sustain steady level flight.

Aircraft impact the climate largely through the release of CO2, which results in a direct contribution to the greenhouse effect, absorbing terrestrial radiation and trapping heat within the atmosphere, leading to rising temperatures. However, it is also vital not to overlook the non-CO2 aircraft emissions such as NOx, soot and water vapour, which result in alternative climate change mechanisms – the indirect greenhouse effect, the direct aerosol effect and aviation induced cloudiness. When accounting for these non-CO2 effects, it can be assumed that the climate impact is doubled or tripled compared to that of CO2 alone.

This report provides the necessary background information to grasp the science behind aircraft emissions and delves into the impacts aviation has on the atmosphere’s ability to cleanse itself of harmful emissions, otherwise known as the oxidising capacity of the atmosphere. It does so through an analysis of three distinct and commonly flown flight routes, investigating the impact that each flight’s emissions have on the surrounding atmospheric chemistry and discusses the potential effects this has on our Earth-atmosphere system.

Read the full report by Kieran Tait

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Read our other blogs about air travel:

  1. To fly or not to fly? Towards a University of Bristol approach
  2. I won’t fly to your conference, but I hope you will still invite me to participate
Watch our latest video on air travel at the University of Bristol.

To fly or not to fly? Towards a University of Bristol approach

Posted on by janet.crompton

We’ve published a short video on air travel at the University of Bristol. 





Here is a blog to accompany the video to give you more detail on the biggest issues that the university (and other similar organisations who rely on air travel) are facing as it works towards making itself carbon neutral by 2030. Caboteer Eleni Michalopoulou, who features in the video, explains more…

The effects of climate change now have almost a daily mention in the news as they become all the more frequent and evident by various studies, reports, blogs and pictures from all over the world. And as the climate crisis escalates, it was of course a matter of time before scientists pointed out the irony of flying to a conference in order to discuss the urgency and issues related to climate change. Of course, there is here an irony within the irony that led to a lot of finger pointing of scientists that do fly and a narrative of ‘unethical scientists’ that ‘don’t practice what they preach’  but we will come back to that a little later when we explore some of the reasons that people (not just scientists) fly.


I must admit that before I attended the workshop organized by the University of Bristol Sustainability Team with support from the Cabot Institute on the 10 June 2019, I had never really considered the actual facts and figures related to the aviation industry. So, I started doing some research and these are only some of the numbers I came across:

On the 17 April 2019, the University of Bristol became the first university in the UK to declare a climate emergency and joined a long list of organizations and institutions across the world in the fight against climate change.  This announcement came to highlight the university’s commitment to become carbon neutral by 2030.

Bike servicing and repair at the University of Bristol

As part of this efforts to accelerate action on its own climate impacts, the University is now developing a plan to address academic and other business travel and in particular air travel. The first task has been to assess the carbon footprint of the thousands of journeys made each year on University business by academics, postgraduate students and professional services staff.

Business travel emissions lie outside the scope of mandatory carbon reporting required in the higher education sector and are not included in the University’s carbon neutral goal. Nonetheless for the past few years the University has collated emissions data on flights and other forms of business travel, alongside those from energy use in buildings and the fuel used by its own vehicle fleet.

In order for the University to monitor and report carbon emissions, it uses three different ‘scopes’.

  • Scope 1 – Emissions are direct emissions from activities owned or controlled by the University, such as University owned vehicles and the fuel they use.
  • Scope 2 – Emissions are indirect emissions from electricity owned or consumed by the University that we do not own or control.
  • Scope 3 – Emissions are other indirect emissions that are related to the University’s activities, such as waste, water and business travel.

Analysis of these data for the business travel plan suggest that emissions from air travel have more than doubled since 2010/11 and now account for nearly one fifth of the University’s total known operational carbon footprint. This growth has occurred against a backdrop of declining emissions from the University’s estate achieved through investment, for example, in improved energy efficiency in buildings.

This was the context for the  workshop on ‘Air travel: Drivers, impacts and opportunities for change’ in order to explore the most efficient way to develop a business travel plan for the University including the constraints and opportunities for managing the impacts of air travel for academic and other business reasons. The Vice-Chancellor for Global Engagement, Dr Erik Lithander, was present in this workshop and highlighted the need to maintain our global impact as a leading university while managing our environmental footprint and remaining committed to our strong sustainability agenda.

One of the most interesting parts of the workshop was the discussion around the reasons behind air travel in the University of Bristol. So, what is academic and business travel usually linked to according to the most recent staff travel survey?  This found the most common reasons (for business or academic travel) were to attend a conference or other forum for sharing research; take part in collaborative projects with other academic or industry partners; and go to other types of meetings on University business. Travel for fieldwork and training purposes was less frequent, followed by attending trade shows and recruitment.

Discussions during the workshop considered the reasons why flying might be the first choice over video-conferencing or other travel modes)’. The following five responses emerged from the roundtable discussions as the key determining factors in the choice of air travel over other alternatives:

  1. Time
  2. Costs
  3. Technological limitations (e.g. quality of videocalls)
  4. The importance of face-to-face interaction, and
  5. Air travel being the default option in funding requirements or travel management companies.

I suppose when I walked into the workshop, my thinking regarding air travel was overly simplistic. I had not realized the complexity of this issue especially for an institution as big as the University of Bristol. During the discussions around the reasons behind flying, three were the reasons that really troubled me in terms of a complex problem that potentially requires a complex solution.

Time

Perhaps the most important issue is the issue of time. A direct flight from Bristol to, for instance, Edinburgh is approximately one hour while the same distance if covered by train is six hours in a best-case scenario. And while for most of us this could be an opportunity to relax and enjoy a lovely trip by train, what about cases where there are caring responsibilities involved, or even an extremely busy workload? This question brings us back to the irony of the irony that I briefly mentioned in the beginning. While climate scientists care, of course, about the environment and their own environmental footprint, in a lot of cases they have families, children, or are responsible for the care of a relative or an individual and increasing the duration of their business trip by 10 or even 20 hours might not be a realistic goal to set.

Costs

Similarly, while a direct flight from Bristol to Edinburgh can cost from £23 pounds, the train from Bristol to Edinburgh ranges between £140 and £280 pounds. Of course, for the biggest part these expenses are not covered by the individual researcher but even so, a very simple question to ask would be ‘why use a substantial amount from the budget to cover a train ticket and not use the cheap option of a plane ticket?’

Physical presence

What was perhaps discussed the most during the workshop was the culture and beliefs behind the idea that an academic’s physical presence would be much more beneficial and could better achieve the purpose of their visit (e.g. research, collaboration, securing funding, networking) rather than the e-presence of the same individual. Can our physical presence be replaced with the help of technology? Can we achieve the same goals through an e-conference than we would if we were there? What can replace a handshake?

I should at this point highlight, that I am not writing the above in defense of flying. I am writing it as a way to reflect on my own thoughts and discussions with colleagues both during the workshop but also afterwards. Afterall, if there was one thing that was evident from the IPCC report was the fact that our lifestyle would have to go through ‘unprecedented changes’ in order for our planet and the climate to have a chance. Perhaps, while a train trip might seem as an inconvenience or disruption to us right now it will be nothing compared to future “inconveniences and disruptions” of a much-deteriorated climate.

I truly believe that it is extremely courageous for the University to start quantifying and addressing its own emissions related to air travel. This effort to explore both the limitations but also the opportunities, by consulting and talking to members of staff is the University’s best bet in order to both meet its very ambitious sustainability goals but also maintain a strong global presence and agenda. Following the workshop in June, a program of wider staff engagement is due to take place continue in the autumn to help develop the University’s approach to air travel. Like many other colleagues, I look forward to the opportunity to contribute to this important response to the climate emergency.

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This blog was written by Cabot Institute member Eleni Michalopoulou from the University of Bristol School of Chemistry.

Eleni Michalopoulou
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