The speakers in my research seminar do not leave the ground to give their talk. Consider the following claim:

If middle-class individuals in rich countries do not significantly reduce their personal carbon footprints in coming years, our grandchildren have no future.

The words "no future" refer to the end of human civilization. If things don't change radically, our grandchildren will find themselves in a world in which civilization, as we normally understand it, has been destroyed. If there are still historians in the 22nd century, they might explain that human civilization started about 3000 BCE (Wilkinson et al., 2014) and ended about 2100 CE.

The future we are creating with our emissions

Accelerating, uncontrollable global warming is an increasingly likely scenario for the late 21st century. In the past two centuries, human activity has pushed atmospheric CO₂ concentration to its highest level in the history of our species. Somewhere near 2030, the increase in global mean surface temperature will pass the 1.5°C mark. At some point after the 2°C mark (nobody knows when), global warming will start to happen naturally and uncontrollably due to climate feedbacks -- even if human emissions completely stop (Steffan et al., 2018). Where that will lead is similarly uncertain, but we do know that 55 million years ago the global mean surface temperature was some 8°C higher than now (late Paleocene thermal maximum; Zachos et al., 2001).

Even without "runaway" warming, the consequences will be catastrophic. In many places, there will unprecedented floods, droughts, bushfires, storms, heat waves, epidemics, and famines. Rising seas will force millions to leave their homes and destroy agricultural land upon which further millions depend. Melting glaciers and diminishing groundwater will affect drinking water supplies for billions of people. Today, some ten million people die prematurely each year in connection with poverty (hunger, preventable/curable disease, violence); this number will steadily increase. Countless species will go extinct, impacting entire ecosystems -- with disastrous consequences for food production. There will be unprecedented mass migration as wars rage over diminishing resources (Barnett & Adger, 2007; Masson-Delmotte et al., 2018; Oreskes & Conway, 2013).

Many of these things will happen regardless of how fast emissions are reduced in coming years. But by rapidly reducing emissions now, we can reduce the future impact of climate change and the probability that it will get out of hand. Obviously, nothing can be more important.

Individuals versus corporations

As part of that effort, the political battle against polluting multinational corporations is central. But the above claim in italics is valid regardless of what happens in the political or corporate arena: If middle-class individuals in rich countries do not significantly reduce their personal carbon footprints in coming years, our grandchildren have no future. 

Almost all the fossil carbon that is processed by big corporations (ExxonMobil, Shell, BP, Chevron, and hundreds of others) is burned on behalf of paying customers. Most of those customers are ultimately (at the end of the supply chain) middle-class people in rich countries. If those people (that's us) stop buying goods and services that involve burning carbon, the price of carbon will fall relative to sustainables and it will no longer be financially worthwhile for big corporations to supply it.

Of course the fossil fuel suppliers must urgently wind down their operations, regardless of what is happening in the marketplace. They must stop drilling for oil and gas and mining coal completely and as soon as possible. Preferably this year rather than next. No question about that. Every ton of carbon burned is a ton too many. The undemocratic power of big multinational corporations is hindering progress in this area. There are nevertheless many promising political and legal options.

But the sentence in italics is also true, and it applies to all professions equally: If middle-class individuals in rich countries do not significantly reduce their personal carbon footprints in coming years, our grandchildren have no future. Possible exceptions include politicians and international aid workers, but there is no reason to exempt academics, business people, lawyers, or artist/entertainers. The relevant difference among these groups is that academics are better informed about climate change and better able to evaluate scientific literature. Academics should therefore be the first to reduce their carbon footprints.

Academic flying

According to the International Civil Aviation Organization, aviation contributed 2% of global CO₂ emissions in 2006 (ICAO.int). The 2% figure is still being quoted, although aviation has grown by 5% per year globally since 2000 (Freeman et al., 2018). Aviation now contributes over 3% of global CO₂, and the contribution of aviation to global radiative forcing (global warming) is about twice that figure due to other greenhouse gas emissions and their complex interactions with atmospheric gases. According to Owen et al. (2010), aviation may have produced 5% of global radiative forcing as early as 2005, and CO₂ emissions from aviation could increase fourfold between 2000 and 2050. Although flying has been getting steadily cheaper, from a global perspective it is still a luxury, affordable to 5-6% of the population (Negroni, 2016). For those who fly, flying represents a large proportion of their individual carbon footprints.

The biggest single contributor to academic carbon footprints is the airplane. A single long-haul return flight typically burns a ton of carbon per economy-class seat, producing 3.7 tons of CO₂. That corresponds to three months of normal living in the EU. A typical academic can double her/his carbon footprint by attending four distant conferences per year, relative to not flying. Grémillet (2008) estimated that flying can triple an academic's footprint.

Electric planes are no solution because it will take decades before they can carry hundreds of passengers, if at all. Biofuels are no solution because they take away agricultural land that is needed for food production and indirectly cause rainforest destruction. Geo-engineering solutions to climate change are no solution because the risks are greater than the benefits.

The academic benefits of not flying outweigh the disadvantages. Many colleagues are skeptical about this claim, so let me present two pieces of evidence. First, in 2014 I stopped flying to conferences unless invited. Since then I have presented my research in Madrid, Oxford, Birmingham, Dijon, Ghent, Maastricht, Prague, Vienna, Geneva, Genova, Katowice, Warsaw, Łódź, Budapest, Cluj, Belgrade, Tallinn, and Vilnius. That's not only a lot of trains -- it's also a lot of diverse academic contacts and research dissemination. My overall research performance is unaffected (more) and I have a long stream of new manuscripts in the pipeline. Second, in 2018, my local and international colleagues and I implemented a new "semi-virtual" conference format at four global locations (Parncutt & Seither-Preisler, 2019; Parncutt et al., 2019). The new format has the potential to increase the number of interesting talks and participants at international conferences and improve documentation while at the same time avoiding flying -- possibly altogether (video - homepage).

North Americans will complain that their trains are even worse than in Europe. The first response to such a statement is that no such middle-class problem is comparable with risking the future of humanity. Second, there is always a solution if you look for it. Academics are creative people, and this is an opportunity to demonstrate that creativity. 

It basically boils down to decisions. North American academics can decide to focus their conference activities on locations within about 1000 miles and travel by train or bus. Instead of traveling to more distant conferences, they can decide to stay home and write a paper. They can also decide to promote low-carbon, high-technology, multiple-location, alternative conference formats. Anyone reading this text can make a decision of this kind right now. After that, the question of whether to fly or not to fly no longer arises, because the decision has already been made. (For me personally, it was a great relief to make that decision, because I did not have to worry about it again.) Similarly, any parent can say to her or his child "I will always be there for you, as long as I live", and really mean it.

It is easier for colleagues with permanent tenured positions to give up flying. It is understandable if others continue to fly, because their careers depend on it. But even younger colleagues without job security can find new compromise solutions, depending on their specific situation. Often it is better for one's career to skip a conference and instead stay home and write a paper.

Academic administrators can decide to stop funding colleagues who fly to conferences. The reason is clear: the future of our children is obviously more important, and there are obvious alternatives. The sooner this decision is made, the better. Every ton of carbon burned today will contribute to climate change for at least a century. 

Here is how universities could reasonably respond, and inevitably will. They will encourage their academic staff to focus on conferences that they can reasonably reach by surface transport, and to contribute remotely to others. Flights to conferences will not longer be financed, nor will registration and accommodation costs of flying participants. Individuals will be free to finance such trips themselves. Conference organisers will still invite keynotes and the university will still pay for their flights provided the conference has more than, say, 100 registered participants per keynote. The money saved by not financing flying will be spent on improving technology for remote presentation and virtual participation and funding open-access publications -- perhaps even funding entire research projects.

If scholars and researchers are still not convinced by arguments of this kind, let them read their own ethical guidelines (e.g. those of psychology). The basic message conveyed by such guidelines is this: Research is fine provided it does not cause significant harm to other humans or non-human animals or to the natural environment. The benefits must be greater than the costs. Applying this idea to international conferences, and given the predicted catastrophic consequences climate change, it is clear that, as a rule, flying to conferences has to stop. 

If a university wants its best research to be more visible and have more impact in the long term, the best bet is to fund open-access publications. Funding conference flying is a relatively inefficient strategy by comparison. Similarly, governments should be ending fossil fuel subsidies of all kinds and investing the same money in sustainables.

How long do we have to wait before people wake up?

These ideas are not new, but most academic colleagues and universities in the world are ignoring them. If we consider our current situation in a detached, quasi-objective fashion, trying to adopt the point of view of future people who will suffer as a result our current negligence, our refusal to change is astonishingly short-sighted and insensitive. Perhaps even cruel. 

Given that this reasonable and plausible interpretation exists, while at the same time acknowledging the possibility of other interpretations, I have a special request for all colleagues and administrators. Please take a multiple-choice examination comprising just one question:

What is the best response to this situation?

A: Ignore it. B: Talk about it. C: Panic. D: Stop flying.

I cannot peer into the minds of other people. But my guess is that most academics are silently planning to start with A, followed by B, C, and D, in that order. Most have been consciously ignoring this problem for over a decade, pretending to themselves and others they don't know what they are doing. I know, because for many years I did the same. When the pressure gets too great, my respected colleagues can imagine long, astute academic discussions, probably at international conferences to which most people fly, after which again nothing will change. Another few years down the track, when things are looking really serious and many academic colleagues are personally affected, there will be panic. 

All along, many academics will be assuming that their work is not only "valuable" (for society) but also "value free" (independent of politics), although the contradiction is plain to see. Therefore, in their eyes, they are not responsible.

Needless to say, the most appropriate solution is to move directly to D, now. Just stop flying.

Avoiding negatives is one thing. Promoting positives is another. The privileged education and social standing of academics give us unusual opportunities to communicate with large numbers of people. That enables us to set an example to the rest of the world. The existence of these privileges and opportunities implies an obligation to use them (Chomsky, 1969). We certainly owe that to our children. But to understand that point requires a level of moral maturity that many people (regardless of academic qualification) never reach (more).

Regardless of how politicians and corporations respond (or fail to respond) to this challenge in coming years, academics will have to stop flying and encourage most other professions to follow suit. That is our role as researchers and teachers with the privilege of life-long education and freedom of speech: to inform, demonstrate, warn. Even politicians could eliminate most flights, communicating electronically instead. Private jets should be universally banned. These are not a political claims; they are obvious statements. They are not quite as obvious as 2+2=4, but the difference is small and getting smaller every year.

Who knows, perhaps some colleagues will dislike this text (or my other efforts to reduce the carbon footprint of academia) and for that reason reject my conference, publication, or grant submissions. But that is nothing compared to what we are doing to our children. Our children are submitting applications for a future that they can live in (more). They are saying: "Please mum, please dad, can we please live a reasonable life like you have done?" So far, their submissions are being rejected without review. Global CO₂ emissions are still rising. That we have a global climate emergency, is obvious.

The existence of a large and growing aviation industry is obviously contrary to the Paris agreement. We cannot achieve the 2°C goal that way, let alone the 1.5°C goal, regardless of what happens in other energy sectors, which of course also have to be radically reduced. To achieve these goals at national and international levels, we have to make flying much much more expensive (doubling ticket prices and spending the proceeds on mitigation and adaptation would be a good start) while at the same time legally regulating the industry, reserving flying for emergencies. Given that global warming is a matter of life and death for a billion people, one could argue that flying is only justified if necessary to save human lives.

If anyone knows of another realistic option, let me know. To those who find this entire argument unrealistic: what could  be more unrealistic than continuing down the track toward self-destruction? How long will it take for that to sink in? The time for "sinking in" is past. Everyone in the middle and rich classes of the rich and becoming-rich countries has to change now. Not tomorrow, but today. The more money you have relative to the global average, and the better your education, the greater is your moral obligation to change. Academics are in a good position to explain that  to everyone, so I guess we had better get on with it.

A thought experiment

Imagine jumping into a time machine and emerging fifty years into the future. By then, most current climate predictions will have come true. Almost everywhere there will be unprecedented, mega-fatal heat waves, floods, droughts, bushfires, storms, rising seas, mass migration, epidemics, famines, drought where glaciers and groundwater used to be, countless extinct species, resources wars. What we normally call "civilization" will be crumbling or already irretrievably lost. Needless to say, not much will be left of the universities; but that will be the least of our problems.

Everyone who reads and understands this document in the year 2070 will agree that academics should have stopped flying in 2019, immediately and completely. They will agree that academics should have been the first to understand the urgency of the situation, explain it, and set an example to the rest of the world. 

That being the case, and returning to the present time, it would be inappropriate to gently suggest or even merely call for universities to consider adjusting their approach to flying. Given the obvious mortal risk for billions of people, it is more appropriate to demand that all universities completely stop funding flying immediately. Even a demand of this kind is too little, too late; anything else would be even less and even later.

For those who find this approach extreme: please look again at the best academic literature. Read about:

• the catastrophic effects of 2°C relative to 1.5°C (ipcc.ch)
• the chance of climate change becoming irreversible as global mean surface temperature increases beyond 2°C (Steffen et al., 2018: Trajectories of the Earth System in the Anthropocene). 
• the extraordinary failure of humanity to respond to this challenge during the past two decades despite countless high-level talks (Hulme, 2009: Why we disagree about climate change)
• the carbon budget, how much of that has already been burned, how much is left, how much has to stay in the ground (Wikipedia)

Putting all this together, it is has now become reasonable to propose that humanity is in the process of destroying itself (Ripple et al., 2017: World scientists' warning to humanity: a second notice). Therefore, we have a global emergency. Therefore, radical change is immediately required.

Given 

• the unprecedented urgency of the situation 
• the universal availability of internet-based audiovisual communication
• the earth's capability to absorb CO2 by photosynthesis, which is about 15 gigatons of CO2 per year or 2 tons per person assuming 7.5 billion people (Reich, 2013: Explainer: How much carbon can the world's forests absorb?)
• the comparable carbon footprint of a single international return flight in economy class  (more)
• the consequent need for academics to fly less

it has become appropriate to demand that university leaders (vice-chancellors, rectors, presidents) decide unilaterally to end university flying completely. Any discussion should not concern whether academics should stop flying, but how: how flying will be stopped, how other aspects of academic life will be affected, how to respond constructively to the new situation. There can be no compromises, half-solutions, or further delays when it comes to a question of life and death for billions of people. 

Skeptical readers are asked to try again to imagine the chaotic, violent, miserable world in which our children and grandchildren will find themselves in fifty years' time. If those future people were to read this document, they would surely agree that things now need to change fast.

Disclaimer

The opinions expressed in the above text are the author's personal opinions.

References

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Chomsky, N. (1967). The responsibility of intellectuals. New York Review of Books, 8 (3). 

Freeman, S., Lee, D. S., Lim, L. L., Skowron, A., & De León, R. R. (2018). Trading off aircraft fuel burn and NOx emissions for optimal climate policy. Environmental Science & Technology, 52(5), 2498-2505.

Grémillet, D. (2008). Paradox of flying to meetings to protect the environment. Nature, 455(7217), 1175.

Masson-Delmotte, V. et al. (Eds.) (2018). Global warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways. Geneva, Switzerland: World Meteorological Organization.

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