Nearly 40 years ago I took a three-day train ride from London to Istanbul, a bus from there to Bodrum, and ended up walking to the village of Gumusluk because there was no road. I spent the summer picking and eating peaches and fishing with the locals. Net result: minimum ecological damage, maximum cultural exchange, and a tad fewer octopuses in the Mediterranean. In today’s terms, this was as green as travel gets.

Now you can get to Gumusluk in a few hours and spend a month there without hearing a word of Turkish. The fish may come from Singapore, the hotels are owned by the British, the villas by the Dutch, and the yachts that call in are in the million-dollar bracket. The place has changed unimaginably in a generation and, as one of the village’s first tourists, I hold my hand up. Had I known then what I know now, should I have gone?

Yes. Green travel is not just what happens at the destination, or indeed how you get there. It does not demand that you eschew air travel altogether or hotels or comfort, or that your holiday is within 10 miles of your home. Rather, it asks you to pack your brain as well as your swimsuit, and to assess and then act on the impact of your visit.

At its best, it’s kind to both place and people, and rewards the host as much as the tourist. It is mostly small-scale, unique and personal. It certainly appeals to the intellectually curious, the ecologically and socially responsible, and to the politically aware. It seeks to add to the sum of knowledge and improve, or at least not harm, the natural world.

It can be on the other side of the world or down your road, in a forest or in the city. Even flying can be justifiable, if you take a plane only occasionally and are sensible about it. The golden rule must be that if our actions hurt in one way, then we should compensate in another.

Dave Martin, who helps run community-owned Bulungula Lodge in South Africa, argues that rather than cutting out flying, we should be selective about where we visit. Africa is the least polluting continent on Earth but most needs the income, jobs and good development that inspired tourism brings. “Cancel your holidays to the rich world and save up for a worthwhile holiday to the developing world,” he says.

At its worst, green travel is a cynical lie, told by travel agents, tour operators, airlines and cruise lines claiming to be green but actually peddling mass, crass tourism. It has been used to cover any encounter with indigenous peoples, any foray into a forest or trip by bicycle.

Happily that is changing. Hotels used to call themselves green if they offered not to change the towels every day; these days, people demand evidence of real commitment to community, place and the environment.

That is exactly what the 75 companies in Guardian Green Travel List do. Some cater for the adventurous, others for those who like their creature comforts. But they are phenomenally diverse; some are community-run, others are owned by international hotel chains. They range from the English Midlands to the deepest jungle of Ecuador.

When I finally left Gumusluk, I was asked if I would like to buy the 15 empty homes at the end of the village for about £50 each. “But why would anyone need 15 homes overlooking the Mediterranean?” I said. That may have been the beginning of wisdom, but it was the end of a possible career in green property development.