- OK, so I'm going to be totally honest with you today. As I've said many times before, I am making this podcast because I want to find out what the experts and the evidence say I can do to genuinely reduce my footprint on the planet. However, right now, I have a big case of wanderlust. I just want to get on a plane and fly somewhere; a tropical beach, a dense jungle, just somewhere I can immerse myself in a wonderful culture and meet amazing people and eat their delicious food. But I know, of course, that flying is terrible for the planet.

[music playing]

Boeing 747 manual tells me a single jumbo jet carries 240,000 litres of jet fuel. And it burns through it at a whopping rate of 4 litres every second. And I know that doing that produces not just loads of carbon dioxide, but also nitrogen oxides that can break down into ozone, contributing to global warming and plenty of other climate impacts too. However, if I get the chance to jet off on an adventure, would knowing all that stop me jumping on a flight?

I said I'd be honest. And I don't think it ultimately would. Would I be cool with that decision though? Absolutely not. I will feel guilty. I'll have flygskam, a Swedish term I recently read that translates to flight shame.

And that flygskam is a big motivation for this episode. I'm Greg Foot. And today's Which? Investigation asks, can we ever fly on holiday with a clear conscience?

[music playing]

Which? Investigates is a new podcast from the UK's Consumer Champion. We work to make life simpler, fairer, and safer for everyone. And our mission for this podcast is simple, find out the facts and see who's actually delivering on the promises we see on packaging in the press or shared on social media. Our first season is focusing on claims of sustainability. From plant based to plastic free, eco travel to electric cars, I'll be figuring out what genuinely reduces our environmental footprint and what is simply greenwashing.

Coming up, the facts speak for themselves.

- Each passenger on a return flight from London to Singapore would account for around three tonnes of carbon dioxide. And that's around about the equivalent of heating a family home for a year.

- I look into whether carbon offsets and biofuels can reduce that impact.

- Here's my pitch to you as a carbon offsetter. You can go on flying. You can fly as much as you like. There's really no problem because I've got this get out of gaol free card. Pay me a little bit of money, it'll be all right.

- And I ask whether the environmental costs could ever stop us jetting off on holiday.

- I don't think that we should ever be stopped from travelling. I actually think it's really eye opening. And it can really change us. To travel is part of being human in the modern world. It's to be able to see other places and other cultures.

[music playing]

- One of the studies that I was reading for this episode, a 2018 article in Nature Climate Change entitled The Carbon Footprint of Global Tourism, suggests that travel is responsible for around 8% of the world's carbon emissions. Now I appreciate that 8% is small. But that is 8% of the world's carbon emissions.

And this article also rightly highlights that our travel footprint isn't just from flying. It's also the accommodation, the bus and boat rides, the food, the souvenirs. And I'm going to explore some of those additional impacts later. But I'm starting with flights.

- So I'm Jo Rhodes I'm acting principal researcher at Which? and I work specifically on the travel team.

- As always, I wanted first to check in with the Which? team to get some context before chatting-- and actually for this episode, grilling somewhat-- the external experts and guests.

- I should probably start by saying that travel is a really great thing. And it can really help. It educates people, it connects people and cultures, and actually makes people care a lot more about the planet. So that's a good thing for sustainability. But obviously the impact of our travel can be quite significant.

And flying is the most carbon intensive. Aviation is responsible for around 2% of global carbon emissions. I mean, you can compare that with road traffic, which is 11%. But I guess it's easier to say that a holiday is a luxury compared to say daily transport or heating our homes.

- Jo raises an interesting point there. Is a holiday a luxury or a right? It's a question I'm going to return to later. There's no question, however, about air travel's environmental impact.

- To give you a bit of context, each passenger on a return flight from London to Singapore would account for around three tonnes of carbon dioxide. And that's around about the equivalent of heating a family home for a year.

- You already heard Jo say this in the episode teaser menu. But I wanted to play it again because it really puts the impact of one, long haul return flight in perspective, especially after last week's podcast on home heating. And it's not just the impact of the carbon dioxide and the nitrogen oxides that I mentioned earlier.

There's also the particulate matter, the small bits of stuff in the exhaust. Clouds form around them. That's what those white contrails or condensation trails are that you see. And they're problematic for the climate too because they, one, block sunlight from reaching us down here, and two, trap heat from escaping back up to space.

- Hello, I'm Jocelyn Timperley. I'm a freelance climate journalist currently based in Costa Rica.

- I asked Jocelyn to paint a picture of how many of us are flying, pre-pandemic of course.

- Just last year some academics from Lund University and Linnaeus University came up with a paper where they tried to calculate this. And they found that 11% of the world's population took a flight in 2018. And of those, 4% flew abroad. And of those what's really important is also that a tiny percentage, it's 1% actually they found that the world's population account for more than half of flying emissions.

- Wow. 1% of the global population is responsible for more than half the world's flying emissions. So you'd be forgiven then if your reaction was on the lines of, well, if it's just 1% of the world's population, that's unlikely to be me. However, the majority of this footprint is emitted by those travelling from high income countries.

At the top of the list of the biggest producers of CO2 from flights is the US, followed by China, Ireland, India, and the UK. And it's worth noting that Ireland is there only because people use it as a stop-off flying to and from America. However, the emissions that come from you taking a seat on a plane depend on where that seat is.

- If you're more packed in, then the kind of emissions per person. So if you're thinking about travelling, it's definitely better not to go first, business class.

- Yes, if you divide a plane's emissions by the amount of space you're taking up, then flying business is worse for the planet than flying cattle class, as it is often called. A fact that may help you a little bit next time you and your neighbour are vying for the elbow rest or your knees are being grazed by the seat in front.

- But also these budget airlines, I think, tend to have newer planes. So if your fleet is made up of younger planes, more modern planes, then emissions will be lower as well.

- OK. So if you do fly, then this sounds like the best option we have so far is a standard class on a budget airlines modern plane. But that plane is, of course, still producing epic amounts of emissions. So can we ever fly on holiday with a clear conscience?

- So Which? did an investigation that found just by picking a less polluting airline, you're going to those emissions. And Skyscanner can actually help you do that. It has a little leaf motif when you're searching for flights, using its tool, and that will show you the most efficient flight for your journey.

- But what does that little leaf icon mean? I mean to me, it implies nature, natural, eco-friendly, even good for the planet, which it surely isn't. What does a flight have to do to get itself one of them? We asked Skyscanner and they told us this.

- We calculate our emissions based on three factors, aircraft type, distance and route, and aircraft capacity. Our calculation maps the aircraft type to its associated fuel efficiency. Based on these considerations, if a flight has at least 4% less than average CO2 for that route, we'll mark it as a greener choice.

- I thought that they might come back to us to say that the flights they mark with that little leaf icon are ones that you can offset the carbon emissions of. Now that is clearly not the case. And thanks, Skyscanner, for explaining that. It is time, however, to discuss carbon offsetting.

- So offsetting is basically calculating the carbon emissions that you're responsible for by taking a flight. And then you pay an amount of money that will essentially offset that damage with a project somewhere that takes the same amount of carbon out of the environment as your emissions basically, so levelling out your impact.

- Sounds great, doesn't it? You take a flight, that flight emits a bunch of carbon. You pay for, say trees, to be planted somewhere that absorb the same amount of carbon from the atmosphere as you are emitting into it, and your carbon score sheet is back to zero. Goodbye, flygskam. No more flight shame, right?

- I know EasyJet and Virgin Atlantic have both come under criticism. They paid to have forests planted only for them later to be cut down.

- Oh.

- And if you consider it takes between 15 and 35 years for a tree to reach its average carbon storage capacity, you've not addressed the carbon problem.

- Sadly, this idea of carbon offsetting flight emissions by planting trees is not as green as it first sounds. It's not just that those trees that are planted on your behalf won't themselves pull that carbon out of the atmosphere for 15 to 35 years as Jo just said. And it's not just that they may be cut down before then. It's the fact that when carbon is emitted, it stays in the atmosphere for hundreds, thousands of years. Which means, for me, this offer to carbon offset your flight just feels like greenwashing.

Indeed, a 2017 study by the European Commission found that 85% of offset projects under the Kyoto Protocols Clean Development Mechanism had failed to reduce emissions.

- Some of the airlines are introducing this option to offset at the checkout when you buy your flight, which is obviously a really good thing. But with Ryanair, it's basically donate a euro and you're done and you can get on your flight and feel really good about yourself.

- A euro. That is not going to buy many trees, is it? That said, last year they did increase that voluntary carbon offset contribution from 1 to 2 euros. Still though, the point remains.

- You haven't offset your flight. You've made a charity donation, which again is better than doing nothing. But it's definitely not offsetting.

- Oh, and for Ryanair this contribution doesn't necessarily go towards planting trees. A couple of years ago, one of their projects at the carbon offsetting donations went towards was a whale and dolphin research group. And I'm not aware whales or dolphins are particularly great carbon sinks.

- Professor Simon Lewis of University College London, he came out and was very critical of Ryanair's offsetting scheme. He believes that they are offsetting less than 0.01% of their emissions with this scheme. And he called it woefully inadequate and a green gimmick, rather than a serious attempt to slow down climate change.

- Now we put this to Ryanair and they replied with an email saying this.

- Ryanair is already Europe's greenest and cleanest major airline. With CO2 emissions of just 66 G per passenger per cab. European passengers switching to fly Ryanair from Europe's legacy flight carriers reduce their CO2 emissions by up to 50%.

- They also added-- and this is my favourite part.

- This is more fake news by Which?.

- Delightful. Looking at their current website, they outline two projects currently supported by the carbon offset donations. One in Uganda, which distributes energy efficient cook stoves to households in the Kampala region. Something they say has a major positive impact by contributing to climate change mitigation and improving the lives of local families. And the other in Portugal, restoring forest in fire devastated areas of the Algarve.

- Here's my big thing with offsetting, right? If there is the ability to pay money to grow trees and then to protect them for the amount of time it requires them to be significant carbon sinks, or to do other things that will cut emissions elsewhere to balance out our emissions, couldn't we just not go on the holiday, not use the flight, but still pay that money? And therefore, be carbon negative.

- We could do that. But I'd really like to go on holiday. I don't know about you.

- Fair. And so would I. So I ask the question again. Can we ever fly on holiday with a clear conscience? Carbon offsetting appears to be off the table, or maybe not enough by itself. But what about the potential of swapping out the dirty jet fuel for something cleaner?

In the long term horizon, we've got the concept of powered liquid hydrogen planes or even electric planes. They're not going to come soon enough. But there's something called sustainable aviation fuel, which you can use in the same plane.

- This is Justin Francis who I'll introduce properly in a bit. He mentioned Sustainable Aviation Fuel there, or SAF, originally made from waste oil. That does mean that it is still fundamentally fossil fuel based. But it's good to be reusing or recycling potential waste.

And if it does reduce emissions, that's a good thing. But SAF became yet more problematic when I read a recent working paper from the International Council on clean transportation. They estimate that by the end of the decade, 2030, there'll be the resources and industry set up to produce enough sustainable aviation fuel to supply just over 5% of EU jet fuel demand. Yeah.

And actually, as the road sector is largely consuming these waste oils, we're going to struggle to provide more than 2% of jet fuel from SAFs. But what about these biofuels that I've heard so much about? Well, here's Doctor Marc Stettler from Imperial College London to explain where they come from.

- Quite a wide range of plants can be used. Some of the older biofuels when people were originally thinking about this were coming from food crops, including wheat, corn, soybean. All of those can be used and turned into a biofuel. So corn, for instance, was used in the US quite a lot to produce ethanol. One of the most kind of successful examples of producing ethanol, which can then go into petrol, is from Brazil where they use sugarcane to turn that into ethanol, which is essentially an alcohol.

- Indeed, Azul Airlines in Brazil did announce a test flight of a plane using this sugarcane based renewable fuel. And while that was way back in 2012 and we've seen few additional developments in Brazil since then, there was a fascinating study released last month with more good news about biofuels. In it, NASA and the German Aerospace Centre found that cleaner burning jet fuels made from sustainable sources can produce 50% to 70% fewer ice crystal contrails at cruising altitude, further reducing aviation's traditional impact on the environment. I should say that that study and all the sources in this episode can be found via the link in the podcast description. And sticking with sustainable fuels, the issue with biofuel is, again, how much we need to produce.

- The amount of supply that becomes available for biofuels is quite varied in terms of the estimates that are out there in the literature. The aviation industry would like to believe that these could be used across most flights. And that would therefore lead to the largest CO2 savings. The reality might be slightly different.

- Jocelyn also has other biofuel concerns.

- The issue with biofuels is that you have to make sure that it itself is coming from a sustainable source. There's loads of examples of biofuels coming from deforested areas of land. If you deforest the land to grow a crop, that's not very good for the climate. And it's certainly not carbon neutral. So the problem with scaling biofuels up too fast, you just end up doing more damage. That's where we've got to be really careful, actually, about the scale up of biofuels.

- So how about if, instead, you create a fuel from scratch?

- Second generation sustainable aviation fuels are synthetically created. It's not about rounding up a bunch of waste and turning it into a biofuel. Second generation is more promising.

If we could get the right mechanisms in place for that, we believe by 2030, we could get 10% of fuel, which is from sustainable aviation fuel. And by 2050, we could get even further. We could get to 30% or 40% or 50%. So you'd be mixing 50% sustainable aviation fuel with kerosene by 2050.

- Ideally, of course, I would like an aviation fuel that was bio-based. This second generation, supposedly named sustainable aviation fuel, would essentially be half kerosene. So still belching out greenhouse gases and the rest. But if that cuts emissions by half, say, compared to a full tank of dirty jet fuel, it is an improvement. But there is a bigger issue here, though.

- Aviation fuel is exempt from duty and from VAT, which means that essentially, the aviation industry gets an enormous subsidy.

- As we've heard in other episodes such as last week's home heating investigation where I discovered that our most viable source of hydrogen is actually from the fossil fuel industry, we always need to look behind the curtain. We need to see who the people or the industries are who are really holding the strings. And yet again, here is a situation where traditional aviation fuel gets the subsidies that make it cheaper than, potentially, greener alternatives.

- We think that's wrong. We think that the cost of flying should increase, probably not popular statement right now given the state of the tourism industry.

- This is Justin Francis again. And I should add that the "we" he's referring to here is his travel company, which I'm going to tell you about very soon.

- We'd reform something called the Air Passenger Duty, which people might be familiar with. We would rename it the Green Flying Duty. And we think that the money that has been raised from the Green Flying Duty would be ring fenced for research and development into making aviation cleaner and greener, more quickly.

- Just before pressing upload on this episode, we heard more from the UK government on their transport decarbonization plan. They've announced that new green taxes on motoring and flying are likely to be introduced with a plan promising to reconsider carbon prices to quote, "help accelerate the move to green fuels." Great news, of course. But as Justin said, this could see airfares rise. The government also pledged to reach net 0 on domestic flights by 2040. And given everything we've heard so far, there's a long way to go.

[music playing]

- I need to introduce you to Justin properly.

- I'm Justin Francis. I'm the co-founder and chief executive of Responsible Travel.

- As you've just heard, he is a font of knowledge regarding the current and future sustainability of travel. And I initially wanted to speak to him as I was keen to widen the focus of this episode beyond just flights to include how eco-friendly, so-called eco travel companies are. And as Justin said, he heads up Responsible Travel.

And when I was researching the company before our call, I read this on their website.

- Our holidays are more enjoyable because they do good. When your trip benefits others, you gain too. All our trips support communities and preserve nature, which helps you get closer to both. So when you travel with us, everyone wins.

- Now don't you worry, I didn't hold back with my questions to Justin. And I'm going to get to some of our discussion around doing good and everyone winning. But first, what did he say when I raised the obvious environmental impact of flying?

- Our advices. Take fewer longer holidays, which means your flying will reduce.

- Yep. You heard that right. His business model would, of course, benefit from more holidays being taken, not less. But he appreciates the impact of flying. And he suggests we reduce the number of flights we take. And this is Which?'s advice too.

- Taking fewer trips, but staying longer. So not binge flying.

- Which actually brings into question then, my earlier conclusion that budget airlines may be the best choice to minimise your flight impact. Yes, for equivalent flights, being bunched together in a more modern plane reduces your emissions. But the advice to be a more sustainable flyer is to replace short weekend trips with fewer, longer trips.

- We also don't use the word sustainable when we attach it to international travel that involves aviation. It isn't sustainable.

- Yes, I used that word deliberately just now because flying on holiday, currently, cannot be sustainable, as confirmed by the chief exec of a travel company. Tell me what responsible travel is.

- When we travel we have positive and negative impacts. And I'm sure all of us would like them to be more positive and to improve places for us to visit next time. But more importantly, for people who live there and call it home. I think that doing good brings you closer to local people and places, gives you a more authentic experience, which is what many people want from their holidays.

- So what do you do differently to what others do?

- Well, I'm pleased to say that there are several others doing good work. So I wouldn't say that we are unique in that way. But the company was founded 20 years ago. I founded the company with just one single idea. It would totally be about more enjoyable travel that did some good.

So it's our founding purpose. You can gather that from the name, Responsible Travel. We have 6,000 holidays run for us by our partners, local partners in destinations. Every single holiday is screened by us for its impacts, both on nature and local communities.

- So how can they claim that their holidays, many of which include an international flight to get there, quote "do good?"

- What tourism does is it supports the local economy, supports the hotel sector, supports restaurants and other tourism providers. We also need tourism because it employs 10% of the world's population, including many people who come from marginalised backgrounds. It's one of those industries, unlike law or accountancy or dentistry, that you can get into around the world with very limited or no education.

So it's an important driver of the world's economy. It's also a big supporter of conservation initiatives. And many of the national parks around the world and other protected areas are supported through tourism.

- This is something that Jocelyn has seen first hand, living in Costa Rica, a country known for its stunning scenery and wildlife.

- I think Costa Rica has done a really good job of promoting its green tourism. So people come to see wildlife and forests and beautiful landscapes. So it does definitely push the idea of conserving these landscapes.

And it brings in money. It's definitely seen as a very positive thing. And it's helped Costa Rica to conserve its forests, definitely.

- And this supports what I read in a New York Times piece recently on the impact of COVID on travel destinations. They said that because many governments pay for conservation and enforcement through fees associated with tourism, as tourism dried up during the pandemic, that revenue did too. And the article says, budgets were cut, resulting in increased poaching and illegal fishing in some areas. Illicit logging rose too, presenting a double whammy for the environment.

- Put yourself in the shoes of someone around the world is thinking about a natural environment, which could be used for a variety of ways, intensive forestry, agriculture, development. And then there's an industry that comes along, the tourism industry, said we would actually like to protect it. We would like to keep it how it is. And we will generate income and jobs for you for the local community.

So what is tourism really doing there? It's providing the jobs and economic argument to protect a place for the future and for nature. And that is vital in our battle against climate change. So tourism is not all bad.

- And to finish off this section, I just want to bring Prince Harry into the discussion. No, not in person, I'm afraid. In 2019, he co-founded Travelist, a non-profit organisation that says they're working hard to identify and help bring about the systemic changes needed in order for sustainable travel to be taken out of the niche and into the mainstream.

In their annual report, Harry says that post-pandemic travel offers quote "an opportunity to do things differently, to do things better." But this is the line that stood out to me. He said, quote "we know that to not travel again is not an option. It is our role. It is our obligation to assist recovery and forge the right path forward, a path where we can again explore our world and expand our horizons whilst the natural environment and wildlife flourish and communities are supported."

I'd love to know what you think about that. Is it our obligation to travel? Let me know. I'm @gregfoot on Twitter and Instagram. And Which? Is @WhichUK.

[music playing]

Now it is of course, possible to lessen the impact of getting to these destinations by simply not flying.

- If you're looking at sort of journey per journey comparison, depending on the exact flight, it probably takes at least 10 times as much CO2 emissions as a train.

- Personally, I love a train journey. You know, headphones in, book out, watching the world whiz by.

- I've travelled all over Europe by train, and I love it. There's huge benefits. The ground travel, you see so much more. You have a completely different experience if you incorporate that into your holiday. As part of your holiday, not just sort of focus only on the destination.

- In May 2020, Which? published figures showing the benefits of travelling by rail rather than air. We looked at research done by EcoPassenger to compare identical journeys from London to various European cities. And I should add that the times quoted here for flights include travel to and from the airport and checking in. And for Eurostar, they include boarding time.

Here's London to Brussels in Belgium. Flying takes 4 hours 37 minutes, and comes at a cost of just shy of 120 kilogrammes of CO2 per passenger. Compare that to the train which takes 2 hours 45 minutes, at a cost of just shy of 8 kilogrammes of CO2, which means-- hang on-- going by train creates less than 7% of the carbon emissions by plane. And it gets you there quicker.

So as expected really, trains are more planet friendly than planes. But what about going by sea? There are ferries and boats for shorter trips. But cruises are, of course, a popular holiday option. What are their eco credentials?

- Cruise companies are keeping those figures very close to their chest. But we know that the impact is huge. They're these huge kind of floating theme parks. They're not bringing any benefit to the places they visit either because people are spending all their money on the ship itself.

- In 2018, Germany's Nature and Biodiversity Conservation Union surveyed 77 cruise ships and found that all but one use something called heavy fuel oil, something the group described as the dirtiest of all fuels. And that's not just used to move that floating theme park. It's also what fuels all the onboard amenities and entertainment, meaning staying on a cruise ship has a much higher impact than staying in a hotel room.

And here's a fact that comes with a gag warning. Friends of the Earth say that in a single week, passengers and crew aboard the biggest ships can produce 210,000 gallons of sewage. There's almost five times that in grey water from sinks and showers and laundries, et cetera. And over a year, 100 million gallons of petroleum products from cruise ships seep into our oceans.

- The challenge with the cruise industry is got some of the worst environmental impacts. But it also creates some of the lowest benefits to people in cruise destinations because people typically eat on board. And of course, they stay on board. And that's before we get on to the issues of over-tourism and overcrowding. And when you have 1,000 people arriving in one go in destinations, particularly the smaller ones, it creates huge issues and congestion, not just for the tourists, but for local people as well.

- Clearly, getting to your holiday destination is always going to come with an environmental cost, even if you went by train or, as we learned in episode 3, by electric car. There are obviously huge emissions from a plane, and clearly, significant impacts with a cruise too. But while we're talking about the eco effect of holidays, let me just spend a minute or so rounding out this picture beyond just travel. And then I'll finish up with what could maybe be done to help us make more eco-friendly holiday choices.

- I'm seeing a colossal amount of plastic waste produced across the tourism industry, which is destroying nature in our marine environments and rivers. I'm seeing a lot of untreated sewage being released into our oceans and rivers. I'm seeing coastlines being developed for tourism and ripping out mangroves because we don't think they look pretty, and we want a pristine beach. I'm seeing a lot of wildlife tourism which gets too close and is insensitive to wildlife, which disturbs the wildlife.

- Plus there's the impact of the food you're eating while on holiday. 80% of the food consumed by the tourism industry in the Pacific Islands is brought in from overseas, something that is no doubt replicated at countless tourist destinations across the globe, especially those "luxury resorts" that offer food from all around the world, not just local dishes using local seasonal foods.

[music playing]

So there's clearly a responsibility on the hotel developers, the tourism industry, and of course, the flight companies and those lobbying for or against alternative fuel options. But it is also on us to ask the questions and to decide what impact we are happy for our holidays to have.

- I don't think holiday is a luxury. And nobody should feel guilty about going on holiday. I think it's really important.

- This is Jo from Which? again.

- The point is not stopping going on holiday, but holidaying in a smarter way and thinking about our impact.

- But how are we supposed to know what that impact is? Well, that is a question I asked each of my guests this week. How can I make more environmentally considered choices when booking a holiday?

- The old days of tourism was that you looked at the price, the destination, and what you could do. And that was your research. And can I afford it? And can I get the time off work, OK?

Well, still got to do that. But now what we're asking is that you think about something more challenging, but ultimately more rewarding. This is not about switching one light bulb for another light bulb or one energy supply for another energy supply or buying even a hybrid or electric car. This is far more complicated than that.

- They don't really make it very easy for us. You don't really get the impact of a flight on your ticket.

- What we need is all travel companies to carbon label, and for them all to use the same methodology so that it's comparable across the board and consumers can make those really valuable choices.

- You need to know not only the carbon emissions of holiday A versus holiday B. But you also need to know the carbon emissions of your holiday compared to other things in your life.

- Carbon labelling could be really helpful. And I feel like it may happen. Again, just before clicking upload on this episode, I read that Marks and Spencer and Costa Coffee are soon to pilot an eco score label on some of their own brand products. Unilever are piloting carbon footprint labels too.

Having the same for holidays would be great. Oh, and before I wrap up, here is a great fact for you. Only one in six of people end up wearing everything they pack for an average holiday. I feel seen. That's definitely me.

And because it's the weight of the plane and what's on it that determines how much fuel it burns, if we all reduced our luggage by a quarter, it would save more than 7,500 tonnes of CO2 each year. That's the equivalent of taking over 2000 cars off the road.

So am I going to fly abroad again in the future? Well, I will be hearing and heeding all this advice. I would love to try some no fly holidays. I'm well up for going and exploring Europe by train. But yes, I will be on a plane again.

Where possible, I will absolutely forgo short trips for fewer longer ones. As I said at the start of the episode, I much prefer to go on adventures where I get to immerse myself somewhere for a while.

And how am I justifying future flights to myself and the planet? Well, I could repeat what my guests said about how tourism can provide economic help by supporting jobs and ecological help by protecting wildlife areas for tourists rather than using it for logging or agriculture. That isn't enough, though, to rid me of that flygskam for me to fly guilt free. I don't think that's going to happen until we have greener biofuels, until we have better carbon offsetting options to mop up the emissions that we do create. And also a travel industry that does more to minimise its impact.

- I think we've all, in tourism, to be honest, got a lot to learn. We kind of want to visit the most beautiful and fragile places. And we both have the opportunity to help restore it, but we also, by visiting the most beautiful, the most fragile places, put them at risk as well.

- Ultimately, we each need to recognise our role in this and make our own conscious choices. And I would love to hear what yours will be. Has what you've heard changed the way you may holiday? What really stuck out for you today?

And if you've got any thoughts or questions, let me know. I'm @gregfoot on Twitter and Instagram. And Which? is @WhichUK.

[music playing]

If you enjoyed this podcast, please do check out the other investigations in the sustainability focused first season. And if you would be so kind to rate and review us on Apple Podcasts, we would genuinely, really appreciate it. I know that podcast hosts always say, please rate and review at the end of an episode.

But it does help you get noticed. And it shows others that it's worth their time to have a listen. So thank you if you do get a chance to do that.

We've got more episodes on their way for you, so do follow us to catch them. And if you've got something that you would like us to investigate, let me know. It doesn't have to be a green technology or sustainability issue. We would love your ideas for future seasons too. Send them over.

Here at Which? we're making sustainability key to what we do, from how we assess the products and services we review to the way we run our whole organisation. That's why this first season of Which? Investigates is dedicated to helping you make the sustainable choices you've told us are so important.

We've got new reviews and advice every day on which.co.uk that will give you the power to make the best decisions for yourself and the planet. So why not sign up for our monthly sustainability bulletin that will bring you all that great content into your inbox. Just head over to which.co.uk/greenemail. And if you want to make the most of your money with everyday personal finance tips, then why not have a listen to our sister show, the Which? Money podcast?

Today's episode was presented by me, Greg Foot. Written and produced by me and Rob Lilly. Editing and original music by Eric [inaudible].

And our executive producer is Angus [inaudible]. Special thanks go to Richard [inaudible], Michael Briggs, Emily Seymour, Yvette Fletcher, Jo Rhodes, Grace [inaudible], and Emma [inaudible]. And I'll see you next time.