Thank you, Ilan. I agree with most of this - and agree I should not have flown to Argentina. However, IPCC lead authors' meetings are definitely not 'procedural, bureaucratic, box ticking', at least for the authors: they are where the reports are planned and written, and the many different chapters coordinate. In theory, it could be done on-line, but it would need more sophisticated meeting software than I have seen to manage the hierarchy of chapters within working groups within reports. I suspect that big multinational companies have this, but academics don't seem to. Also, those of us based in remote rural areas - like me - often don't have the reliablity band andwidth that multinationals do.

I salute you for your concern on the climate. It will be great if everybody thinks like you in their various activities. However, I would like to tell you that it all depends on the importance or priority or unavoidability or social commitment.

In the Conferences we share our research ideas and practical experience. So it must to contribute and dissolve the problems. So here avoid other concern

Good question. I tried to stop flying but failed. The commute by train or boat from Europe to Singapore and return sounded like a pleasant alternative but ultimately took too long, and would be a lot more expensive too than flying. I do, however, now avoid intercontinental flights for meetings or workshops only and will attend these events only if I am in the region anyway. Event organizers should give more thought to allowing people to contribute remotely, watching presentations and attending meetings without having to leave their home towns. Picking the most suitable location for a meeting should also take into consideration the distance that most people would need to fly. IUCN's 2016 Congress on Hawai'i was probably not the best example of this, as pretty much all participants had to fly long distances to get there.

Remote contributions need to be looked at again. Multinational companies don't fly busy executives around the world getting jet-lag: they meet electronically. Regionally meetings with a few international participants added electronically can work - I have done it once many years ago - and is no less interactive if done well. I think that one problem is that the hotels and conference centers we use for big meetings have no interest in reducing the number of physical visitors.

There are multiple twitter conferences tin the recent past that allow researchers to present and communicate remotely. I thought they were quite effective, and a brilliant idea. Below is a letter in Science. Authors (Avery-Gomm et al. 2016; https://science.sciencemag.org/content/352/6292/1404.2) write:

"Conferences allow researchers to present findings, exchange ideas, and develop networks. Unfortunately, they also incur high financial costs for participants and high environmental costs in the form of carbon emissions associated with air and other travel. Twitter—already popular with many academics (1)—can reach large audiences in a short period of time. We propose that global Twitter conferences could be a cost-effective and low-carbon complement to traditional conferences.

The World Seabird Union hosted Twitter Conferences in 2015 and 2016. The 2016 conference featured 72 presenters from 11 countries. Each presenter had 15 minutes to present six tweets (at 140 characters each). The constraints forced presenters to be succinct and use photographs, infographics, or animations to explain their work. The 2016 World Seabird Twitter Conference hashtag (#WSTC2) was used by 633 people in 3931 posts, compared with the 540 people who wrote 2700 posts tagged with the 2015 hashtag (#WSTC1). The success and growth of these events demonstrate the effectiveness of Twitter as a peer-to-peer platform for scientific interaction and science communication."

Ornithology groups seem to be particularly active in this aspect (https://www.bou.org.uk/conference/bou18tc/)

Thank you, Sreekar, but do you think this works as an alteranative to meeting people? I find it helps to meet someone at least once before electronic communication can take over. Still, if twitter, WeChat, and other electronic media replaced half the conferences, that would mean a huge reduction in the environmental impact of 'saving the environment'.

How many is enough, Michael, and others? Once every two years, once a year, twice a year, more?

There are three things to remember regarding international conferences. First, the scientific community commuting to present their research is infinitesimal compared to all the flyers around the world. Second, senior and prominent researchers attend in the conferences do have significant impact on the early career researchers and research students. Finally, remote presentation are utter useless because people are less interested in others work than presenting theirs. Therefore, there must be less sharing of research at the remote conferences. Moreover, no advice from one another.

In nutshell, if you stop commuting to international conferences, you are going to contribute a little in cleaning up the environment, but the next generation scientists inspired by the scientific leaders at the conferences is much more than you are polluting the environment.

I believe international travel by university staff (i.e., not just ecologists) may not always be justified and for ecologists/environmental scientists in particular it is a conundrum. Many universities in the UK highlight 'sustainable travel plans' that are confined to travel to and from university campuses (e.g., encouraging cycling, public transport, park and ride schemes, etc) but conveniently ignore international travel not just by academic staff, but also support staff (e.g., for marketing purposes), and management. It is time universities recognised this and encouraged more use of technology to avoid such travel but, moreover, when flights are taken, that universities make it policy to offset their carbon footprint, for example by contributing a percentage over and above the cost to organisations like the World Land Trust. I know carbon offsetting is only one component of the problem highlighted in the original post and has also attracted controversy in the past (see link at end) so I would be interested in people's thoughts on this idea.

https://www.theguardian.com/environment/2007/jun/16/climatechange.climatechange

I have also met this 'cycle to work but fly to meetings' attitude, and I think universities could do more by providing the sort of electronic meeting facilities that multinational companies have. The problem with offsetting, however good it is, is best seen by reversing the order: if you have paid to increase the global carbon sink, does it then make sense to also pay to fly so that this sink is offset by an equal source? Also, stabilizing the global climate will require both massively reducing sources and massively increasing sinks, and this won't work if we trade off one against the other.

Designing electronic meetings that are as dynamic and engaging as in-person meetings is a hard task. But as scientists, we investigate hard problems all the time! Can we approach this as a research problem? Test impacts of different electronic meeting styles by randomly giving some grad students funds to travel to a conference and some access to electronic meeting.

I wonder of your total flights how many are related with international meetings? vs. doing fieldwork or collaborating abroad? or vs. leisure travel?

Is a good question, and is excellent to think (and act) about our contradictions, but still I wonder how important are international meetings vs. other travel motivations?

Trevor: a great idea and you are right that we should treat this as a scientific problem. Randomization might be difficult with the small numbers of grad students most labs have, but we could perhaps do this with advanced undergraduate classes and a local meeting.

Jose: also a good point. I think many of us combine conferences with fieldwork or overseas collaborations, or combine them with an annual holiday that would have been taken anyway. All these would reduce the environmental impact that could be attributed to conference attendance.

Well living and working in an island country where the next conference is at least three hours away by flight there is little else than to fly to conferences. For conferences here in Fiji we -at times- organize the possibility to present through online tools....

Optimization studies could also be done for choosing a meeting location which requires minimal flight and other travel distance for expected meeting participants. I often get invited to meetings in the Gulf States, and because few of the participants live and work there, it means everyone flies in. But maybe for international meetings, the location is actually quite good as it may be central to most - I don't know how that works out. Certainly, the emissions from air conditioning are not a plus for climate change mitigation. Anyway, I think it is crucial as conservation scientist to at least show that we consider the various travel options. Richard, it would make a fun paper to write: Where conservation scientists should and shouldn't meet. Which factors come into play (flight distance, availability of public transport, heating/cooling needs of venue, what else?)..

Chose only one international meeting a year, the one with the highest potential for making an impact in your and other people´s research. Maybe limit to one every two years and try to develop more meetings and collaborations locally (in your country). I believe the problem is not flying every now and then, but flying all year round. We can be more strategic when choosing meetings. Some of them are too big with very little meaningful interaction, it´s just not worth it.

Thank you, Carlos, for some common sense. It is hard to see why anyone has to fly to more than one a year, and I think we could improve local and regional meetings by adding in long-distance participants electronically. Indeed, if regional meetings truly substitute for global ones, then flying in a limited number of speakers from another continent has much less environmental impact than flying all the participants to that continent.

I just was in GLasgow on the World Forum on Climate Justice (of course by train) and it became clear that individual actions that contribute to the climate crisis are violating human rights, particularly flying. People really suffer from the human caused climate crisis and there is no excuse for causing the suffering, even collectively. A lot of people gave talks via Skype (from the US and Australia) and there was still great personal exchange between people coming from Europe by train. I am surrounded by colleagues which don´t fly anymore or only rarely, for some of them see here but I know much more

https://noflyclimatesci.org/

Here is an example of a flight free conference on degrowth of aviation

https://stay-grounded.org/conference/

I agree with most of the statements given already concerning regional conferences. We won`t reduce the climate crisis without flying less and scientists can contribute a lot to this reduction with their high carbon foot print.

Thank you, Suzanne. Given that only a few percent of the world's population (2-3% in a 2006 paper) flies internationally ecah year, academic travel is clearly an exercise in privilege and and thus needs very strong justification for the environmental harm done. Our was environmental scientsist ork - we hope - is important, but is it important eno Are we somehow exempt?ugh?

Good points, Daniel, and I am going to try to advance these policies in China, where almost all major institutions are now on high-speed rail. High-speed rail has a much lower climate impact than flying, because of greatly reduced carbon emissions and non-CO2 climate impacts, but an assessment of total impacts should also assess the environmental costs (for climate and biodiversity) of constructing a line between home and conference site. The total climate impacts of flying have been estimated to be 2-4 times greater than the impacts of the carbon dioxide released by burning fuel alone. The additional climate impacts come mostly from aircraft-induced ice clouds, including linear contrails and larger, irregular, and persistent contrail cirrus.

We should also keep in mind that researchers from developing countries are disadvantaged when it comes to international conferences; such as those from Madagascar who experience refusals to issue visas; besides they don't usually have international credit cards, which prevents them from entering a hotel room even when the entire stay is paid in advance by a donor.

Yes, this is certainly a big issue, but holding international conferences in low-income countries is surely not the most efficient way to deal with it. Rich-world scientists talking to each other in luxury hotels in poor countries is likely to be good for neither. At my institution in China, we pay airfares for early career scientists from low-income countries to attend meetings and training courses, and we get them visas.

Hi Richard, thank you for opening this discussion. I agree with you that conferences are often a burden on the environment and a tremendous cost in the face of dwindling funds for environmental sciences. I have seen that many conferences are attended near the end of financial years, when budgets need to be spent - but could probably be better spend on bursaries or internships. I recently turned down an invitation to a scientific meeting because of air quality issues - I didn't want to attend the conference because of the poor air quality in the host city. This was not the first time that air quality affected my decision. This seems to be terribly hypocritical, because I am guilty of travelling for conferences and research, which is part of the problem. Whereas I always felt that the research trips were more beneficial, I have also wondered how much international research should we really be doing. Perhaps some impact-benefit analyses on research-related travel would also be useful. As for conferences, it's probably obvious, that travel should be avoided the further the conference, the larger the meeting, and the more distant or broad the topic - but it should be up to the individual to make his/her own conscientious decision. Any ideas on evaluating travel for research would also be welcome.

In studying for my comprehensive exam I came across this statistic quoted from Stern (2007, p547):

"Emmissions from deforestation between 2008 and 2012 [are expected to] total 40GT CO2, which alone will raise atmospheric levels of CO2 by 2ppm, greater than the cumulative total of aviation emissions from the invention of the flying machine until at least 2025."

I'm curious how the debate on the impact of flying has gotten so heated given this estimate and what the data show today. Surely the few academics flying to conferences to share research and knowledge are dwarfed by those travelling for industry, business, and pleasure. And the impact is minimal given the continued rate of deforestation and industrial emissions worldwide.

There are multiple issues here. First, carbon emissions alone greatly underestimate the climate impact of high-altitude flying, which mostly comes from aircraft-induced ice clouds. Secondly, flying is increasing as a proportion of total emissions, since industrial emissions are flat, and flight emissions that occur in international airspace are not covered by the Paris agreement. Thirdly, and in my view most important, if you are telling the world that we are in a climate crisis you should not be contributing disproportionately to it. There are other ways of sharing research and knowledge. Multinational companies don't fly their top staff around: they meet on-line and we can do the same.

We don't argue that it is OK to kill a few people, because their deaths will be dwarfed by those killed elsewhere, and I don't think we should argue that the damage we do as environmental scientists doesn't count for the same reason. Being able to fly long distances every year is a privilege available to only the wealthiest 3-4% of the global population, but everybody suffers from the impacts of those who do.

I am really delighted to see this discussion going on in this way. It relieves me towards a lot of colleagues which deny their personal responsibility if it comes to flying.

Not necessary---- It will simply increase carbon foot print. Moreover model of one country does not fit to other. Better to attend local level conferences

if you think CO2 is the main driver of climate change...you must calculate how much you are contributing in climate change by burning fossil fuels and how much you are contributing in mitigation of climate change doing conferences

In theory I could fly to an environmental conference in, say, Chile, and offset all my climate impacts by giving a 15-minute presentation that persuaded other people to stop flying to conferences that are ridiculously far from where they live. Obviously, this is silly, but I suspect it is more-or-less how many senior environmental scientists justify attending remote conferences. They are 'saving the world' so their inspirational presence justifies the short-term costs. There certainly are people for whom this argument is reasonable, but those I know will only go if they can combine a plenary - more people and more time for inspiration than talking in a parallel session - with some other activity that also offsets the environmental harm.

Yes, I fully agree.

The justification issue is the core problem. I once supervised a master thesis which focused on justifications for flying (the student compared "normal citizens" with scientists and NGO representatives from so called green areas) and found out that the "normal" group in general flys less and is more honest with what it is causing and the "green scienstists/NGOS" are using (and really in large numbers and systematically) use as justification what you are quoting: "we have to save the world" and therefore we are allowed to fly. "It is part of our job" while the other fly for pleasure (holidays). This is their justification.

What was even more shocking was that some of them even don`t have a bad conscience at all, no dissonance they have to justify or to argue away. They just continue to think they are so privileged that they are of course allowed to continue to fly. They were - and still are - so surprised if you mention this issue.

please take a look on the website www.sailtothecop.com

Sail to the COP will sail 10.000km ⛵️ to the UN Climate Conference in Chile, for a fair and sustainable future of travel! 🌏

This fall Sail to the COP will sail with 26 young changemakers to the UN Climate Conference (COP) in Chile!

All details on www.sailtothecop.com

This is a fantastic idea! From SW China to Buenos Aires for my IPCC meeting would have taken at least 6-8 months, I think, and that prospect would have made me consider the trip a lot more seriously. Someone needs to organize a climate change meeting in Hawaii, with arrival by sail a requirement for attendance.

An interesting topic and discussion. Not only IPCC, but also UNFCCC meetings, will bring thousands of people from different parts of the world to the host cities annually. Some thirty thousand people attended the Paris annual UNFCCC meeting in 2015. The emission and the cost would be huge. It is the time to think about how to make the activities more effective and efficient.

Well raised point Sir....However, the answer to such query lies in the fact that all such discussions are held in AC rooms...

Obviously, there is not a lack of knwoledge to reach a more sustainable world but a lack of action. So, yes, flying to international meetings is a bad choice, espacially regarding that there are technical solutions to participate without any travelling!

Sometimes it is easy for people working in EU or USA to say: go to local meetings, avoid planes. This is not an option for someone working in Africa, Latin America, Asia. It could even be used as an argument to organize conferences only in rich countries like "the community is more concentrated there and they will generate fewer gas emissions". Science is an international effort and it should be inclusive to all scientists around the globe, despite it cost more gas emissions. I agree that efforts could be made to avoid excess traveling, but this could not be an excuse to centralize science or close frontiers.

I agree 100%, Facundo, since I have spent my career in Asia. But there has to be better way of doing this than having EU and USA scientists talk to each other in exotic locations. I can see several possibilities: regional meetings to which a small number of useful EU and USA people are invited; multi-center meetings connected electronically; purely electronic meetings, with the help of 5G, low earth orbit satellites, and other new technologies; meetings where there are a high density of scientists - USA, EU, China - with funding to support attendance from other countries. There must be other options, but I don't think 'business as usual' is one of these. What do you suggest?

Multi-center meetings connected seems to be a nice idea. However, I still think that making conferences in peripherical countries could fulfill the purpose of strength local science. The problem that I observe is a few people from rich countries travel a lot, sometimes too much. Probably because it is not expensive for them. At the same time, many scientists around the world are quite isolated. I found hard to think about the problem without thinking in inequalities. Science isn't global as many scientists think. In many cases, travels should be reduced, but in many others this statement is unfair. Virtual meetings could help at the same time making conferences more inclusive too.

This is a useful graphic from the BBC on comparative climate impacts of different modes of travel, based on UK Government data. It probably underestimates the impacts of long-haul flights, since the biggest impact of these may be from contrail cirrus and this is hard to quantify.

Carbon Emissions, Pollution, Ecological Footprints (defined in numbers by explorers or in most of the cases not defined) all are products of our activities where magnitude may differ. For example a bicycle has its own footprint in production and preparing dedicated bicycle lane. In India, repairing shop and waste collector adds to this chain. All these many times are unseen and considered invisible. Everything has some ecological cost. Relevance to society/person (at a given point or time) is the prime factor at that moment.

Counter arguments may go on different dimensions but human consciousness is the first thing to accept or deny own actions, and human intelligence must have put in place to visualize the impacts of alternatives to that.

Even connecting to this post and sharing views all these have significant impression on nature !!!.

Yes, but the magnitude matters when we are trying to balance the global thermal budget. Bicycles aren't in the emissions list, but the share of construction and repair costs, plus bicycle lanes, per kilometer of travel must be very much lower than even the most efficient train (which also has construction and repair costs, and needs continuous infrastructure betweeen estinations). Cancel one international conference trip and you pay for a lifetime of bicycle trips.

I actually calculated that my recent trip to Edimburgh from Chile equaled 10 years of daily commutes to my work from home by car (which i avoid by using my bicycle). My thought is that strrngthening regional meetings and using tech for online activities should the way out

Comming back to the question "should environmental scientists fly to international conferences": No, of course they "should" not! For those who have doubts, just have a look to Paris Agreement (Art. 2): It commits us to making this transition. It is a common agreement of the contracting states, that decarbonisation aims net-zero emission in 2050. Even if we aim this goal, we will have only a 50-50 chance to reduce global warming to 1.5 degrees (s. IPCC report)! So if scientists accept they are also concerned by this societal, political objective - the answer should be totally clear: Do not fly! From my point of view, destroying the earth for all coming generations and other species is the real unfairness.

Yes. I think a reasonable alternative to this is to conferences organisers to develop compensation models, for example, by adding a fee to the conference subscription which can be later donated to environmental restoration programmes wordwide (see the Cambridge's Student Conference on Conservation Science, https://www.sccs-cam.org).

The fee amount could be calculated based on the average distance the participants would travel to get to the event.

The one thing worries me with this model is whereas it is fair to charge the same compensation fee amount to participants from different regions (e.g. developing and developed countries) as this could become an additional constraint to participants from poor regions.

Although compensation schemes are clearly better than nothing, they have obvious problems. For flying, most just calculate the carbon emissions, so the larger impacts of contrail cirrus and other non-carbon emissions are not compensated. More generally, if you can afford to pay to absorb 3 tons of CO2 emissions it seems silly to then emit 3 tons so your action has no net benefit! Meeting the Paris targets will require BOTH maximum emission reductions AND maximum carbon dioxide fixation. If we allow one to offset the other we cannot achieve the target.

I do agree with the comments above. Why not apply compensation according to the emission rate of the country of origin, i.e., researchers from developing countries would be taxed less than those of polluting countries

Good question, thanks. Now, I only do conference "close" to where I am, so if I have fieldwork in Latin America i m looking for some conference around (train, bus). I m not travelling to different continent anymore!

A widespread view in this discussion seems to be that young, developing world, isolated researchers really do benefit from international conferences and - presumably - benefit more if at least some older, rich-world, non-isolated researchers also attend. This would argue for having conferences mostly in the well-connected more-developed world: Paris or LA (or, perhaps, Beijing or Bangkok), rather than Madagascar, Sri Lanka, New Zealand, or Hawaii. Two questions occur to me: 1. Do conferences have enough other benefits to argue that we still should - at least, sometimes - fly everyone into Nairobi or Dhaka? 2. Or should we just give up on flying to conferences altogether and go all-electronic?

This is a really interesting discussion with lots of good suggestions. Clearly we need to be thinking about our personal carbon footprints and avoid unnecessary travel. When it is necessary to fly (e.g. for field work) what do others think about offsets? The World Land Trust seems like a good option: https://www.worldlandtrust.org, however, I understand the criticisms and the similarity to buying indulgences. Are offsets a cop out? To me it seems better than nothing, as long as we also take steps to minimise our carbon footprint.

Thank you, Louise: I will look at the World Land Trust! If it is necessary to fly, then reputable offsets are surely better than nothing, but you need to offset non-carbon impacts too, which can potentially be several times larger. See: Bock, L. and Burkhardt, U.: Contrail cirrus radiative forcing for future air traffic, Atmos. Chem. Phys., 19, 8163-8174, https://doi.org/10.5194/acp-19-8163-2019, 2019.

R. T. Corlett good point! I hadn't thought about non-carbon impacts.

I am not sure how robust the Bock and Burkhardt results are, but the EU is apparently struggling with non-carbon impacts for its proposed compulsory (?) flight offset scheme.

The impact of each of us footprint in a world with 7.735.000 inhabitats is tiny. The root of the problem is the overpopulated planet and only a few are working to reduce its counteractive impact (http://populationmatters.org).

Here you have some figures ( https://www.worldometers.info/world-population).

Exactly, overpopulation and very few people to reduce their carbon consumption are really the biggest questions. There might be two possible reasons for this part. 1) they don't believe or care about climate change and any actions to mitigate it; 2) they know the changing climate and willing to contribute some reductions, but they don't know how to reduce their own daily consumptions.

For the first condition, many environmental activities are taking very radical marches to ask the governments coercively reducing carbon emissions. One of

the most ambitious protests is organised by Extinction Rebellion recently (https://rebellion.earth/international-rebellion/worldwide/). They are trying to persuade governments to declare a climate and ecological emergency status of climate change. But is it too radical to forbid any meat industry and even recreate a new government which is led by environmental conscious Citizens’ Assembly?

For the second condition, I guess most are happens in developing or high-developing countries. Many people among this part, even didn't take any air travel during their past life. But they waste food, use no well-processed fuel, buy lots of inferior and high-pollution stuff, and never have been taught or gave chances to recycle garbage. How much could this part fill-gap the carbon emission target?

keep in mind that several institutions sponsoring such participation reimburse costs of travel, including per diem ... after return of the participants to their home country: this limits again for the wealthy only