DW: Mr Herrmann, what is  - in terms of sustainability - the worst trip I can take?

Frank Hermann: A cruise to the Antarctic, including arrival and departure by airplane, or a Caribbean cruise. First you have to fly there before it actually starts, and emissions from the plane and ship double the impact on the environment. 

Cruises are becoming increasingly popular. Why should we try to avoid them? 

Cruise ships use heavy fuel oil on the high seas. It's extremely high in sulphur and especially damaging to the environment. In the ports in which the ships spend about 40 percent of their time, they have to use marine diesel fuel, which is slightly cleaner, but they still pollute the environment enormously, because their engines run 24 hours a day. Added to high sulphur dioxide emissions are nitrogen oxides, soot, particulate matter and CO2. In addition, food is usually flown in specially - for instance, from Germany to the Caribbean! Moreover, passengers sleep, eat and drink on board. Cruise tourism hardly benefits local populations at all. 

Just what does "sustainability" mean in relation to tourism?

It's about environmentally friendly and socially responsibletravel. Tourism has become a mass phenomenon, so the pressure on resources and nature is constantly increasing. People fly frequently, use a lot of water and produce a great amount of refuse. The countryside gets built up because of tourism and in some places biodiversity decreases. In addition, especially in developing countries, local people suffer because of low wages, child labor and sex tourism.  

Why are many people environmentally aware in day-to-day life, but fail to take those considerations into account when planning vacations?

Quite simply because we're not used to doing so. Taking a holiday means relaxing, letting go, and not worrying about anything for a change. Of course that's hard to square with what we could and should do. But habits can be changed - not overnight, but in increments. And perhaps at some point governments have to help - with awareness campaigns, information and, if there's no other way, with restrictions or regulations. 

When a flight from Berlin to Paris costs only half as much as a train journey, does responsibility really lie with travelers? Shouldn't government policies do more? 

The fact is that flying is currently actually subsidised. Air passengers do not have to pay value added tax for their route, but rail passengers have to pay the full amount. So we have competitiveness issues here. To date there is no worldwide CO2 emissions agreement for the transport sector. Air travel is being kept artificially cheap. Others have to pay for the environmental damage and that, of course, is unfair. 

Can you buy a clear conscience with CO2 compensation payments? 

Voluntary  compensation is a sort of interim solution. The problems lie elsewhere - in the fact that air travel is being kept artificially cheap and is not included in the Paris Climate Agreement. However, it's still better for people to make voluntary compensation payments to offset flight emissions than to do nothing. But to avoid a flight always has priority. 

What is done with the money I pay in compensation?

It goes into climate protection projects, generally in developing countries. That can be a biogas plant in Honduras, solar cookers in India or reforestation projects - a lot is happening in that area. Nonetheless, all that cannot give you carte blanche to fly endlessly. 

Will low-cost airlines disappear at some point because their behavior is too environmentally damaging? In that case, will only the rich be able to get to know the world via long-distance air travel?

Tourism is already a very elitist business. There are many travel destinations that ordinary people cannot afford. That's nothing new. But we have to learn to pay for the damage we cause and accept that travel becomes more expensive if environmental damage is included in the calculations and subsidies eliminated. We will probably fly less frequently in the future, but that's not bad. We'll stay at our destinations longer, can relax more and and get to know host countries better. However, we will have to do without the shopping weekend in London and the nightlife break in Reykjavik. 

Tourism is booming worldwide. The sector has a positive image, creates jobs in developing nations and emerging economies. Despite that, you believe tourism tourism doesn't only bring benefits. Isn't that the case? 

Yes, because it's generally mass tourism. You have to look at the local working conditions. They usually involve seasonal jobs, badly paid, with long working hours. And there's often no plan B. Many countries rely solely on tourism, which creates dependency. You can currently see that in Tunisia, Egypt and Turkey. When tourists stay away because of the security situation, hotels close, and suddenly tens of thousands of people are jobless, with no alternative source of income. 

What can I do to plan my next trip fairly and sustainably?

You should inform yourself thoroughly in advance about your destination and generally avoid bargain holidays - because someone will ultimately pay for that bargain: either the enviroment or other people. Don't take a long-haul trip every year, fly only occasionally and carry a small amount of luggage. That way less aviation fuel will be used, which also reduces strain on the climate. Avoid cruises.

A bicycling tour starting from your own doorstep is very environmentally friendly. Leave your car at home and travel by train or coach. Act respectfully and ecologically on vacation: take a shopping bag to the market instead of using plastic bags, use rechargeable batteries and don't run the air conditioning constantly. There are many small things that do make a difference. After your trip, offer feedback to your tour operator about how sustainable it was. And discuss the subject with many people to increase public awareness. 

You yourself are in Costa Rica right now. How are you traveling? 

I flew to Panama - there was no other way to get there. But I'm staying for three months and using only public transportation here. And of course I will be offsetting the carbon emissions from my flight by paying compensation - as I should.

Interview: Christina Deicke

Frank Herrmann is a business economist, worked for many years as a  tour guide in Central and South America, implemented development projects, writes travel guides for the Stefan Loose Verlag publishing house and gives lectures and seminars on sustainability. His book "FAIRreisen - ein Handbuch für alle, die umweltbewusst unterwegs sein wollen" (Fair travel: a handbook for all who want to be environmentally aware when traveling) is one of the winners of the 2017 ITB Book Award in the category of specialist tourism literature at this year's ITB travel trade show.