Reflections on energy and housing


Jenny Love, UCL Energy Institute

I’m going to be leaving academia in a couple of months. Aside from my colleagues being able to finally get some peace and quiet and not having their chocolate supplies taxed on regular occasions, there are some other benefits to this. One is that it has made me reflect on what I have learned whilst doing a PhD in energy and housing. Here are four reflections that you may find interesting.

1. We still don’t really understand a lot of factors behind energy use in buildings.

Much of the blame for this can be attributed to a poor evidence base for physical performance of houses. For example, not enough studies have measured energy use and linked it to real measurements of heat loss from the building. Researchers like Virginia Gori, Sofie Pelsmakers and Sam Stamp are working on these actual measurements.

If we don’t understand how energy is used in the first place, this makes knowing the effects of things like retrofit quite difficult to predict. Researchers like Ian Hamilton are using the best data we currently have to assess the effect of energy efficiency measures.

2. Social scientists and physicists/engineers must go further than just collaboration

We have an unfortunate tradition in our field of a lack of respect between physical scientists and social scientists. What I mean by saying we must go further than collaboration is not just working together and bearing with each other – but setting an example of genuine appreciation of the other’s discipline – including stopping dissing each other’s disciplines behind our mutual backs. When I started my PhD I didn’t know much about social science, and therefore used to be quite rude about it. Now I have come to see that it’s the people who bring about the physics in buildings that I like to study. For example, I described here how when houses are retrofitted, the outcome is determined by the amount by which the occupants adjust the heating. Researchers have to understand what made the occupants adjust the heating, and then the effect that this has on energy use.

The best combination of social science and physics in one project I’ve seen is the work Lai Fong Chiu and Bob Lowe‘s Retrofit Insights team are doing, here. As it happens, the two lead authors of this study are married. Now, although this happened before they wrote the study, there’s nothing to say it couldn’t happen the other way round – you never know, multidisciplinary collaboration could lead to love. In my role as Dr. Love I’m happy to point you towards eligible physical or social scientists with whom you could start a multidisciplinary collaboration.

Another person to keep your eye on is Adam Cooper of UCL STEaPP, who is doing great work in starting to develop the theoretical framework within which social science and physics can fit together in order to study energy use.

3. ‘Behaviour Change’, like religion, is (mis)used as an excuse for all kinds of wrongs

What I mean by ‘Behaviour Change’ is trying to get occupants to reduce their energy use by changing their home heating behaviour. This is only beneficial if there is actual evidence that occupants are exhibiting wasteful behaviours in the first place. In my case study sample in social housing, many of them were heating far less than average and trying to get them to turn the heating down would not only be morally wrong but also bad for the house (leading to more mould, etc).

The second problem I have with ‘Behaviour Change’ is that it is sometimes used as a pretend solution in order to avoid the real issue – the fact that our housing stock is among the least thermally efficient in Europe. We need to get on with insulating it, instead of trying to make people colder by using less heating.

I’m certainly not against occupant engagement. Quite the opposite. What I would recommend it looks like is firstly listening to the occupants about how they do use the heating, and then, only if they are up for it, deliver tailored advice which will help them meet their heating needs using less energy. Also. we should be giving advice on wider aspects of maintaining a healthy home, like how to ventilate adequately.

4. Separate energy/climate change policy from warmth policy.

A crude description of the way retrofit policies worked during the time of my PhD is that energy companies ‘offset’ their CO2 emissions by funding retrofit of social housing. There is very little measurement of whether energy or CO2 has actually been saved, but if there were, it would be seen that some occupants do not save energy but have a warmer home instead – in fact, this is what the occupants need. However, this would be counted as essentially a failed policy, even though the occupants now have a better quality of life. Maybe that’s why no one measures the actual savings.

There are two agendas going on here  – allowing people to be warm in their homes, which is very important, and mitigating climate change by reducing energy use, which is also very important but is the opposite to making people warmer. The more you do of one, the less you do of the other: in my mind, the trade-off is like this:

trade off

I think our climate change and energy demand reduction policies should not target
social housing – there are plenty of other places to focus energy demand at. This sector
needs policies measured in terms how much more comfortable the previously-cold
occupants become.


So, there are some thoughts. I invite you to challenge or add to any of them in the
comment section below. As always, feel free to contact me on if you would like to have a more detailed discussion on anything raised above or have any questions about energy and climate change in general.

Should we invest in Carbon Capture and Storage?

power station

Jenny Love, UCL Energy Institute

Based on a lecture by Prof Geoff Maitland, Imperial College, London

1. Context

In the energy field, a common saying is, “There’s no silver bullet”. That is, there does not exist a solution to the question of which single clean energy source we should use, since energy demand is too large for any of them to supply on its own and thus we need to combine a lot of technologies. However, when it comes to funding to get these technologies off the ground, there are a lot of possible energy sources and not enough money to fund them all. Therefore the limited money should be used to fund the most promising ones, and this requires a kind of competition between technologies to show that they are more viable than others, in contradiction to our acknowledgement that we need a combination of them.

Carbon capture and storage – the processes of recovering CO2 before it is released into the atmosphere and burying it underground –  entails high costs to bring it to commercial reality. In this context of limited funding, what is its potential, and should we invest in it over other technologies?

The following simple overview is mostly shaped by a recent lecture by Professor Geoff Maitland of Imperial College London, filtered of course through my own interpretation and limited understanding.

2. Some brief science

I won’t talk much about the science of carbon capture and storage (CCS) as it can be found elsewhere if you’re interested. Briefly:

There are three ways to do the ‘capture’ part of CCS (which, by the way, is the most expensive bit). You can capture the carbon before or after the burning of fuel (‘pre- or post- combustion’, or you can burn the fuel in a special way (‘oxyfuel’).

Once captured, the CO2 is transported usually via a pipeline, and injected deep into underground spaces as a supercritical fluid (not too quickly, otherwise the rock will crack). Once it’s there, we have to make sure it stays in – from my simplistic understanding, by a combination of not letting it escape while it’s a gas (‘capillary trapping’), getting it to dissolve in water (‘dissolution’) and longer-term getting it to solidify (‘mineralisation’).

3. How positive or negative are the benefits and disbenefits of CCS?

Maitland argues that after energy efficiency, CCS is the cheapest and greenest way to mitigate climate change. He does not by any means suggest that we don’t need other technologies too – for example he points out that even in theory only a third of our CO2 emissions can actually be captured and buried (10 gigatonnes out of our global annual release of 30 gigatonnes). This is because many CO2-releasing applications are not stationary large power stations, but e.g. moving vehicles and domestic boilers, which it would not be cost-effective to fit with CCS.

CCS advocates often describe themselves as realists, since their premise is that fossil fuels are here to stay, at least while we transition [slowly] to a low-carbon economy, and especially for developing countries. Therefore  CCS is absolutely essential if we are going to mitigate climate change.

Concerns have been raised about the effectiveness of CCS, especially in terms of the energy it takes to do which decreases the overall energy produced at the power station, the safety and guarantee of storing CO2 underground, and the time it will take to get enough plants working. A Greenpeace document, False Hope, lays out some of these concerns. Maitland’s argument is that while these are real concerns, their extent is not is great as purported in the Greenpeace report.

4. What is the current state of the technology?

According to Maitland, the technology is “in good shape and ready for widespread deployment”. Its constituent parts, such as capturing CO2, and pumping gas into underground reservoirs, have actually existed for decades due to their use by different industries.

There are various CCS pilot projects going on around the world at the moment, including:

– An interesting project in Masdar, United Arab Emirates, who are powering the capture process by concentrated solar power, here:

– A plant operating since 2004 in Algeria, here:

– A French plant operated by Total, here:

As for the UK,  CCS is part of the Department for Energy and Climate Change (DECC)’s heat strategy to 2050. For the moment, the government and the UK research councils are going to help fund the construction of up to 2 commercial projects. Those two look like they will be in Aberdeen and Yorkshire. The decision as to whether they will both go ahead will be made in early 2015.

5. So if the technology is ready, why isn’t it being done commercially?

It comes down to lack of two things: incentives and certainty. Lack of incentives is seen in that carbon is not taxed according to the environmental damage it does; lack of certainty in that the carbon price and future regulation about carbon storage have not been set out. Is is therefore too risky for companies to invest in CCS assuming that it will be economic in the future.

6. Conclusion

I’d like to conclude with the following statement from Maitland’s lecture: “The real cost of energy from fossil fuels is the generation costs PLUS the CO2 mitigation costs”.

In other words, at the moment we’re paying an artificially low price for energy, and any way in which we generate clean energy in the future will come with an increase in energy price. But, remembering the Stern report in 2006, it’s cheaper to pay more for clean energy now then clear up after the mess we make from global warming.

I think we need CCS; I agree with Maitland that we should develop it now but then phase it out if non-fossil-fuel energy can one day provide for energy demand. The main thing we need to get it going is a decent carbon tax, then industry will be falling over to buy CCS and no one will have to wait for government funding.

(More detailed information for keen people here)

A different view of climate change


What do you think of the infographic below? It was created by

Its raison d’etre:” Many of us hear the term climate change, but don’t really know how climate change is changing the environment and what it means to inhabitants of earth. This infographic will show how bad climate change has become and what it means for all of us.”

<a href=’‘ title=”></a>

What’s the latest in climate change research?

Jenny Love, UCL Energy Institute

With help from Hannah Arnold, Department of Atmospheric Physics, University of Oxford

The field of climate change research has been rapidly advancing. It is important to keep the general public up to date with the work that is going on, to show how the predictions of the effect of mankind on the climate are becoming increasingly sophisticated.

This article is designed to start off simple and become more technical as it goes along, so that there is something for everyone. Therefore at the point when you feel like falling over, well done for getting that far, and feel free to skip to the conclusion.

1. Is there a clear graph I can show my friends to demonstrate manmade climate change?

Source: Global-scale temperature patterns and climate forcing over the past six centuries, Michael E. Mann, Raymond S. Bradle & Malcolm K. Hughes (Nature, 1998)

Not this one. Although this famous ‘hockey-stick’ graph, showing increase in temperature (some versions have CO2 as well) over the last few centuries is everywhere,  no one likes it any more. This is because it doesn’t show that temperature rises are human-induced and it doesn’t set the context of the changing temperature over thousands and millions of years, and so people like to argue about it. Don’t bother showing your sceptical friends this one.

I would recommend something like the following set of 2 graphs, which will help you get the get the point across clearly…

Source: presentation given by Myles Allen on behalf of Oxford University and, 2008.

This is how you explain to people the story told by the set of graphs:

–          We have reasonable data for the global average temperature (plotted in red on all 3 graphs).

–          We collect data on CO2, aerosols, the sun, volcanoes. CO2 and aerosols are manmade; the sun and volcanoes aren’t.

–          We use a model (see below) to predict what the temperature should be in two situations. First of all, with all the influences we can think of: natural ones like the influence of the sun, and volcanoes, and manmade ones such as fossil fuel use and aerosols. We predict that the temperature should rise overall – and look at the first graph: the way in which the temperature is predicted to quickly rise (grey line) fits very well to the observed (red) data.  Then we turn off the manmade influences,  keep the natural influences, and predict the temperature again (grey line in second graph). Modelled temperatures do not show the same rapid increase (incidentally the red rate of observed change is higher than that which would be associated with natural climate variability).   This is a way of showing the effect of manmade emissions on the global temperature.  

2.        How do we know what the climate will be like in the future?

The above was so last century. It’s all very well reconstructing what happened in the past, but how do we predict the future when we can’t test what we’ve done? We need to delve into the world of modelling…

A bit lower down on the cool scale, by ‘modelling’ I mean describing the earth’s systems – one example being the atmosphere –  in mathematical equations. The equations are based on physical laws, such as Newton’s laws of motion. The equations typically involve how a property, like momentum of a particular bit of the atmosphere, changes over space and time, so that you can then predict what the momentum will be at that point in space at a later point in time.

But modelling the atmosphere is, as I learned in my degree, flipping difficult. For a start, where do you put the boundaries? For example, there’s practically no point just describing the atmosphere by itself, as it is linked to the ocean in many ways – the ocean removes CO2 from the atmosphere; the atmosphere removes heat from the ocean; etc. But even an atmosphere-joined-to-ocean model isn’t good enough, as that ignores important interactions with the land mass and ecosystems… and also the atmosphere isn’t just one blob; you need to represent different bits of it in space (this is called ‘dicretisation’) since there is dynamic mixing of gases and differences in temperature throughout…

Very quickly, you start needing a supercomputer. Or, you can use clever solutions like, who ask members of the public to let you run your model on their computer as if it is an extension to theirs. They have been getting results out for a few years now, thanks to the general public!

So what kind of modelling advances have been made recently? Some of the following is paraphrased from chapter 8 of the forthcoming 4th IPCC report,

a)      More systems linked together

The goal is to advance from individual models of particular systems or groups of systems (e.g. ocean-atmosphere) to what’s called an ‘earth simulator’ – that is, containing as many systems as possible.


This image from the model shows the output from  some of the various systems included in the model: clouds, land surface temperatures, sea surface temperatures and sea ice. If you want a fascinating insight into the process of adding features to the model, and the ways they spot errors, here’s one: I particularly like the bit that says: “Model crashed after 2 years with atmos noise around South Pole.” Damn South Pole. Why can’t we just put the South Pole in as a constant…

b)      Better inclusion of feedback

Some effects of global warming act to further speed up the warming. More famous examples include higher temperatures causing methane to be released from peat bogs and thus further warm the planet, and ‘surface albedo’ feedback – that is, melting ice changing the colour of the planet and causing more sunlight to be absorbed and emitted as infrared radiation rather than reflected as ultraviolet radiation, causing further warming.  Less famous examples include the carbon cycle – how living things react to the increase of CO2 in the atmosphere and increasing temperatures and how that might decrease their ability to take in CO2. Also, there is soil-moisture-precipitation feedback, which as the name suggests is to do with changes in the moisture content of soil affecting how much it rains.

All of the above are starting to be included in climate models, to further increase their prediction power.

a)      Making space and time blocks smaller

The aim is to be able to put small-scale events such as cloud processes in the models so as to be able to see how they interact with larger events we can already model, like the advance and retreat of the major monsoon systems, the seasonal shifts of temperatures, storm tracks and rain belts.

The HiGem model I talked about a minute ago divides the ocean up into ‘squares’(ish) of 25 km length and width. This means that ‘small’ phenomena like clouds can be represented. In the same way, getting short-term processes (like the chemistry of the atmosphere) and long term ones (climate) to come together in the same model is a work in progress at the moment.

3) How do we know that climate models are correct?

The answer is that they’re almost definitely not correct; the question is more:

3) How do we represent uncertainty in climate models?

There are three main types of uncertainty in atmospheric modelling:

INITIAL CONDITIONS UNCERTAINTY: data from ground based or satellite observations is not collected at every single point in space, so we have to estimate what is going on in between. A small error in this can amplify as it propagates through the model – but this source of error is only important for weather forecasting, not climate modelling.

EXTERNAL FORCING UNCERTAINTY – ‘forcing’ is anything which changes the amount of radiation the atmosphere lets in or out. Most forcing types, such as the sun’s influence or regular changes in the earth’s orbit, we have got very good at predicting. So the main uncertainty is how much CO2 we’re going to emit in the next 50, 100 or more years. This error is very important in climate modelling, so the IPCC deals with it by modelling a range of scenarios involving different emissions.

MODEL UNCERTAINTY: this isn’t about the data you feed the model with, but the ways in which the equations of the model are just an approximation for how the physical processes in the world work. For example, since you can’t put every cloud in there, you have to put a parameter in for ‘clouds’, but it might not be right. Normally, you’d do a ‘sensitivity analysis’, which involves working out how much it matters if your ‘cloud’ parameter is a bit wrong.

The IPCC uses a method called multi-model comparison, which is where it sends some input files to about 30 approved institutions across the world, so that each can run it on their model. Each institution gets a different result, and in this way the IPCC can get a feel for the model uncertainty. The problem is, that’s not a rigorous mathematical way of treating uncertainty, and will underestimate it.

So the following work by Hannah Arnold of Oxford University is using a different approach to represent model uncertainty, called stochastic parameterisation (have you fallen over yet? If not, read on…). In each timestep, the first thing her models do is solve the Navier-Stokes equations on the global scale – no problem. The devil is in the detail – one then has to estimate what your ‘small scale’ processes (like clouds) are doing in each square of space. But we cannot precisely calculate what the clouds will be doing, so to represent the uncertainty in this estimate she (intelligently) includes random numbers in the calculation. Once the globe has been simulated once, this is repeated about 40 times with different random numbers, and comes out with a different answer every time. This gives a more rigorously mathematical way of seeing the total uncertainty of the forcing. You can read more about Hannah’s work here:

4) What climate processes and effects are we confident of, and what are we less sure about?

In relative terms, ‘global dynamics’ is sussed. That is, the behaviour of large-scale phenomena like temperatures in different regions, winds and pressures are well known. Smaller-scale phenomena like cloud processes, manmade aerosols, and the interaction between clouds and aerosols are less well known.

Ocean processes should be mentioned here – there are some very sophisticated models out there. Still, it is difficult to model things like the jet stream which moves heat from American to Europe, because it is turbulent on a small scale.

5) What’s next?

Can we attribute particular extreme weather events to manmade climate change? People have been talking about this for a while, and the latest report to come out is here:

This isn’t about prediction, it’s about taking events which have already occurred and trying to calculate the probability that they were caused by man’s influence on the climate. How?

The answer, again, is modelling. Given that a particular extreme weather event or set of events was observed – such as recent increased drought in East Africa – a climate model can be run with and without human influence to see if it is that influence which makes a difference as to whether the increase in drought occurs. This is vastly simplifying the actual modelling processes, which give probabilistic results as opposed to the clear-cut ‘yes’ or ‘no’ answer my description seems to imply.

The above report does not claim to have absolutely succeeded in such ‘detection attribution’ as it is known, but instead to be ‘a step along the road’ towards the development of an attribution methodology.


In conclusion, the science is solid and the models are including more and more of the earth’s systems. Error and uncertainty are treated explicitly such that scientists know the level of confidence they should have in a particular model result.

So I think we can leave the climate scientists to it, being confident that they are doing a good job of describing the effect of our actions on the climate.

While they do so, here is a short list of how you can do your bit to reduce emissions – compiled from all my previous blog posts so far!

–          Get your essential amino acids from eggs instead of meat.

–          Don’t travel by plane.

–          Get the defaults changed in your office as to when the lights/heating come on, what temperature the heating/cooling comes on at, etc.

–          Find out which bits of your house aren’t insulated yet and do it, perhaps under an incentive scheme like the Green Deal.

Also here is an interesting article on how to get people who have decided they don’t believe in anthropogenic climate change to reduce their emissions anyway…

More useful links:

Can we ever fly green?

Jenny Love, UCL Energy Insitute

With help from Olivier Dessens, UCL Energy Institute & Oliver Sleath, Credit Suisse

A few years ago I decided to stop flying until it becomes eco-friendly. This was because I’d heard that going on aeroplanes is pretty much the worst action you can do in terms of climate change impact – and if you call yourself an environmentalist I think it’s vital to practise what you preach.

The question is, will it ever be possible to fly without causing global warming? This article will look at the climate change impacts of aviation and the changes that need to come about to limit the damage.

As motivation for you to invent an eco-friendly aeroplane, you won’t be able to get rid of me from the UK and its vicinity until you do.

The ways that aeroplanes cause climate change – in order of importance

1.       Contrails and cirrus formation

I’ll start with a surprise – the biggest climate change impact from aeroplanes is not CO2, nor anything else to do with burning fossil fuels specifically…but an effect called ‘contrails’ – condensation trails forming when a plane crosses a mass of air with particular thermodynamic properties making it ready to form ice crystals (technically: “supersaturated to ice”). The plane triggers the formation of the ice crystals by one of several means: changing the pressure, temperature or planting droplets for the ice to form around. The effect of the ice crystals is to trap heat in the earth-atmosphere system – the technical term is ‘radiative forcing’.

A Nature and Climate Change report claimed that, “…net radiative forcing due to contrail cirrus remains the largest single radiative-forcing component associated with aviation.”[i]

Did you know this was the biggest global warming factor? I didn’t.

2.    Greenhouse gases

Aeroplanes emit gases which cause climate change. There are two types: ‘Greenhouse Gases’ (GHG) including carbon dioxide and water vapour, and gases such as nitrous oxides (NOx) which are not GHG but have an impact on the chemistry of the atmosphere and change the concentration of ozone and methane, which are potent GHGs. Again, ‘radiative forcing’ is the most common measure to use when calculating the overall effect, so that people like you and me can just look at the end result and not have to worry about the complicated atmospheric chemistry that  happens between exhaust being emitted by the plane and resulting global warming. However, the radiative forcing metric does not take into account the future effect of long-lived gases, such as CO2, which will stay in the atmosphere for hundreds of years.

Some factors which affect the radiative forcing are: the amount of each of the gases present, their efficacy in trapping heat, their lifetime before decaying into something else, how high the plane is, and where the plane is over the earth (since there are local differences in distributions of e.g. ozone). Concerning these last two – there are some heights at which the resulting chemical reactions will produce more GHG, and some where it will produce less. One thing I learned in my physics degree is that modelling the atmosphere is a tricky business.

Given these problems of contrails and gases which cause radiative forcing, are there any actions which would lessen or eliminate their respective formation and release?

Possible solutions

1. Efficiency increases

Cutting down the amount of fuel used decreases the CO2 and other greenhouse gases emitted into the atmosphere. How could such fuel a decrease come about?

At the moment, efficiency increase is focussed on advances in engine technology. Possible the most groundbreaking technology that will actually be a reality within the next 3-5 years is the Pratt & Whitney geared turbofan: It is claiming 16-20% reduction in fuel burn compared to conventional engines. However, there is normally a trade-off between CO2 decrease and NOx increase, so I’m not sure what the change in NOx is from previous P&W engines.

Potentially the greenhouse gas issue could be helped. Unfortunately, a 20% reduction in fuel burn over the next 5 years will probably be negated by a 5% annual growth rate in demand for aviation (this is called the ‘rebound effect’).

And unfortunately the contrails issue is still with us.

2.  Alternative fuels

(this bit is summarised from this book:

‘Biofuels’ covers a large range of substances. One definition is: “A type of energy derived from renewable plant and animal materials”.[ii]

The principle of using a biofuel in a jet engine is similar to that of kerosene:

Fuel + oxygen = energy + waste gases (CO2, water, etc).

The two fuels most suitable to put in a jet engine are biodiesel and a type of synthetic kerosene, called Fischer Tropsch (FT) Kerosene. We will rule the former out using a measure called ‘energy ratio’ – energy in the finished fuel compared to non-renewable energy used to produce it. For biodiesel, this is less than one. Forget it. For FT Kerosene, it’s 18-44, so we’ll go with this one. You can make FT Kerosene out of lots of different organic materials; what shall we use?

In the previous blog post, here:, I mentioned ‘Life Cycle Analysis’ – the principle of trying to calculate the total environmental impact of a product, following its production from raw materials. It has been shown[iii] that although certain biofuels cut greenhouse gas emissions by more than 30%, their supply path causes more other environmental damage than petrol – mostly from the resources needed to grow them. The report advises that damage is most limited by using grasses, biogenic wastes and wood to produce the fuel.

However, none of the LCA analysis includes the specific use of the fuel in aircraft – and thus does not include the contrail issue. I’m sad to say that the contrails do not go away with the use of biofuels.

3. Rerouting aeroplanes

Now, as we have seen, the location of the plane in the atmosphere affects both the likelihood of contrails forming and the chemical reactions which occur when its exhaust is emitted. Is it possible for aircraft to modify their paths such as to cause the least radiative forcing possible?

The first thing to point out it that contrail formation is seasonal and affected by weather[iiii]. So when we say ‘modify’ paths of aircraft, we’re not talking a once-for-all shift upwards or downwards, but an adaptive, real-time system of air traffic controllers sending a particular plane higher for a few hundred miles then back down, to avoid the contrail forming regions it comes across. There are academics working on this: I think their logo nicely describes what I’ve been trying to say:

Is this going to be practically possible?

a)      Practically, can an aeroplane fly higher or lower? The current height is ~40-45,000 feet. Take them lower and they burn more fuel and are noisy. Take them much higher and, like Concorde, they need a new type of engine and a new type of wing, both of which are able to deal with the lower air pressure – air being essential for lift force and provision of oxygen in the engine. Theoretically, since contrails are 2000 ft high and aeroplanes could go 5,000 ft higher without more expensive engines, contrail avoidance could be possible. It is then a matter of political will.

b)      Is it possible to predict where the contrail forming regions are before the plane gets there? Yes it is, and subsequently meteorological data could be fed to air traffic controllers, who would then talk to pilots who would react accordingly. Feedback from planes to air traffic controllers could be given via cameras on the back of aircraft which show whether contrails are being produced or not. Inevitably this requires a whole-system change of how air traffic control works – our current flight paths have been set up and left as they are for at least 10 years so the thought of reactive rerouting would be a bit of a shock. Passenger safety is the primary concern of the aircraft operators, not climate change.

4. Alternative holiday destinations?–about/tourist-information

Maybe not. But how about:


There is potential to reduce the environmental footprint of aircraft, by efficiency increases, alternative fuels and intelligent routing strategies. There are still a lot of unknowns in how much damage limitation this will result in, and many things about the system need to change if all three strategies above are to be used. My conclusion to this is that it’s currently best not to fly, especially if you have the choice, and come back to this blog in 20 years to find out what has changed.

Please feel free to ask questions and add comments.

Optional extra

Here are answers to 2 questions people might ask you if you decide, shock horror, not to fly. I don’t expect everyone to agree with my answers.

1)      But going travelling is enriching and makes you a better person.

Quite probably true. But go and spend a week amongst a different social class or religion where you are. The most enriching experience I’ve had recently is spending time on a council estate in Coventry. And not everyone can afford to go travelling so we can’t say it’s our right/you have to do it to be a good person.

2)      Can I just offset my carbon?

I think this is the wrong attitude. Only do this if you don’t have a choice whether to take the flight. Never use it as an influencing factor in a decision, otherwise carbon offsetting could increase demand for flying.

[i] Ulrike Burkdhardt & Bernd Kärcher 2011.  Global radiative forcing from contrail cirrus, Nature Climate Change, 1, 54-58 (2011)



Zah, R., Böni, H., Gauch, M., Hischier, R., Lehmann, M. and Wäger, P. (2007) LifeCycle Assessment of Energy Products: Environmental Assessment of Biofuels, Berne: EMPA

[iiii ]Ficheter, C. SUSANNE MARQUART2, ROBERT SAUSEN, DAVID S. LEE3 The impact of cruise altitude on contrails and related radiative forcing. Meteorologische Zeitschrift, Vol. 14, No. 4, 563-572 (August 2005)