Tag: aviation

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

 

 

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

How the UK government is tackling climate change – a good plan or on course for disaster?

Posted on by janet.crompton
Steve Smith, a researcher working for the government’s independent advisors, the Committee on Climate Change (CCC), came to visit the Cabot Institute on 7 February 2014.  His talk was about whether the UK is on course for tackling climate change, or rather, the UK is on course for meeting its 2050 target of 80% reduction in carbon emissions.  It was a real eye opener.  Here I summarise the talk and the main points made by Steve.  All figures taken from Steve’s talk.
 
Background
 
The CCC consists of several high profile board members, including Lord Deben, Sir Brian Hoskins, and Lord Krebs amongst others.  As a group, their role on the mitigation side is to independently advise the government on UK emission targets.  The UK is legally bound to meet the 2050 target of 80% reduction of CO2 emissions below 1990 levels.  Being legally bound to this commitment means the government has to meet this target.  Steve wasn’t quite sure what the implications would be if the UK government broke the law by not meeting the emissions target by 2050. [Update: the EU has now agreed to a 40% reduction in emissions by 2030].
 
Extreme weather events will become
more common
The current risk of impacts from climate change are set out in the latest IPCC reports.  It is agreed that 2 degrees of warming will exacerbate current climate-related impacts such as increased risk of floods, drought, food insecurity, human displacement, plant and animal disease, etc but that technological advances and human resilience should be able to live with this. Beyond 4 degrees rise many systems will just not be able to adapt – a blunt warning if there ever was one.
 
The current 2050 target of 80% reduction of emissions keeps it in line with a 2 degree warming scenario. This equates to approximately 20 – 24 GT CO2 Kyoto emissions by 2050, which itself implies that each person living on the planet in 2050 will only contribute 2 tonnes of CO2 per year.  This is a similar figure to 6000 miles in your car (an easy annual commuting amount).  Steve pointed out that the total emissions from electricity in 2010 were almost the same amount as total emissions that will be allowed in 2050.  This is not a joke, we will have to meet these targets and we will have to severely cut our carbon emissions.  So what I want to know is what’s the plan?
 
What is the government doing?
 
It seems the government does have a plan and it has had a plan for a few years now.  A long and winding road sort of plan (it stretches 40 years and Steve also admitted that the plan is likely to change over that time period), but it’s a plan nonetheless with a hopeful outcome. Currently the government looks at reducing CO2 emissions by implementing cost effective measures across the economy.  Examples include increased implementation of electrification and Carbon Capture and Storage (CCS) within industry, and district heating and air source heat pumps for buildings.
 
Nuclear power could
help decarbonise the UK
Looking at one of these key measures in more detail, electrification, it is vitally important to not only increase reliance on electricity as a power source (rather than gas or oil) but also to decarbonise electricity production, producing a win-win situation.  The government aims to do this in steps.  The first step is the decarbonisation of base load electricity production into the 2020s.  Base load electricity is the minimum amount of power made to meet minimum demands from users.  Increasing nuclear power could play a big part in this transition.  From the 2020s onwards, the government will aim to decarbonise peak electricity, the stuff that’s needed on-demand like when we switch on our kettles during an ad-break.  The timescales do seem quite long but it takes around 9 years to build a nuclear power station, so put it in perspective the timings aren’t actually that long.  However it is questionable whether we can actually wait until 2050 to become decarbonised for fear of hitting that 4 degree global temperature rise in the meantime. 
 
Decarbonising electricity is one of the most useful things the government can do especially as most fossil fuel driven machines can be electrified – including our cars.  Steve admitted there was one area that was proving difficult to decarbonise – the aviation and shipping sector.  The CCC are still working out how to make this area more efficient as it is a really difficult sector to change.
 
What are the costs to the UK economy?
 
The CCC estimates that the resource cost of reducing CO2 from all sectors would amount to 0.5% GDP.  If there was a scenario in the future of high fuel prices, this cost would drop to 0.1% GDP, but if fuel prices came down we would pay more – around 0.8% GDP. Rather interestingly, 0.6% of costs of reducing CO2 fall in the power sector. So should the government put up the cost of fuel to reduce the resource cost to the UK as a whole?  It’s not as clear cut as that.  Fuel poverty and economic competitiveness are huge issues which need to be carefully considered before any price hikes.
 
The CCC is confident that all government projections will be wrong by 2050. To counter this the CCC have come up with some bottom up scenarios – Max (decarbonise everything), Stretch (optimistic carbon reduction but not ideal), Barrier (the most likely scenario but the worst for CO2 savings).  By mixing and matching these scenarios across all sectors as appropriate, multiple scenarios have been created and it is from these multiple scenarios that the CCC can keep resource cost below 1% GDP for the UK.  
 
How are we doing so far?
 
We’re doing well to decarbonise our cars.
Image by Danrok, Wikimedia Commons
From the first period 2008 – 2012, the first carbon budget was met. Greenhouse gas emissions were reduced.  However, the main cause of this has been attributed to the recession and only 1% of emission reduction was from low carbon energy measures. 
 
The good news is that the UK is ahead of schedule on the decarbonisation of cars. However we are falling behind on non-traded emissions such as cavity insulation. We are looking like we will be on target for the second budget (2013 – 2017) but not budgets 3 (2018 – 2022) or 4 (2023 – 2027).  If the UK is to meet these targets then the government needs to improve future policies and speed up the rate of change to a decarbonised society.
 
Shale gas – a game changer?
 
The USA has kicked heavy emission coal off the system by investing heavily in shale gas (aka fracking) and in doing so has radically (and unwittingly) changed its climate policy.  Steve questioned whether shale gas could be a game changer in the UK.  Rather interestingly, it seems that not much extra gas will be produced in the UK by 2035 if shale gas was put into the mix.  UK gas demand turns out to be significantly higher than what the UK can actually produce (including that from shale). Questions then arise, for example, if you are offsetting imports of gas where are those imports coming from? How are they being transported?  What amount of CO2 is being released in the process of transportation? 
 
Methane leakage from shale gas is also a problem.  The CCC have found that methane leakage from shale gas would be more beneficial to decarbonisation due to the overall emissions from shale gas being less than the amount of emissions from current transportation of Liquified Natural Gas (which has a much smaller amount of methane leakage and larger amount of emissions overall). Any reduction is better than no reduction and the government thinks that a well regulated shale gas industry could help the UK reach those decarbonisation targets.
 
A healthy low carbon diet
 
Image by Richard Croft, Wikimedia Commons
Decarbonising the UK is going to be tough but there are net benefits from doing so.  One of these net benefits is health.  Although it is difficult to quantify the health impact of all CO2 emission reducing methods, we can quantify those such as reducing congestion, improving air quality, and getting people on their bikes doing more exercise.
 
A question was asked of Steve at the end of the talk…why are we not efficient in all of these sectors already?  Steve responded that people don’t act entirely rationally, that decarbonisation takes time to filter into people’s mindsets and that subsidies for the wrong sorts of fuels does not help.
 
So should the government do more to embed a low carbon mindset into its people and industry? Or should we be educating ourselves and personally reducing our own carbon emissions (the non-traded emissions)?  Should we just demand more of our government, put the pressure on the policy makers and inspire current and future generations to do more and be more in a low carbon world? The CCC and the government doesn’t have all the answers.  It’s up to research institutions, like the Cabot Institute, to put their collective heads together to develop solutions to help decarbonise society and to engineer new low carbon technologies, with support from government and industry.   
 
The UK has become a lot more efficient since the 2050 targets were introduced, the government is legally bound to meet these targets so it is serious about the job in hand, and as a result its policies have been changing to reduce emissions.  The government just has to ensure it continues to act on the CCC’s recommendations.   

 View the slides from Steve’s talk.
 
This blog was written by Amanda Woodman-Hardy, Cabot Institute Administrator, University of Bristol.

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Amanda Woodman-Hardy

 

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