NEW YORK: Six-in-ten (60%) of leisure travellers in the US, or some 105.3m people, identify themselves as "sustainable travellers", according to a new survey that finds these consumers to be relatively young and wealthy.

Travel marketing platform Skift reported that Mandala Research, a Virginia-based research firm, conducted an online poll in early 2016 of almost 2,300 US adults who had taken at least one trip during the previous 12 months of at least 50 miles away from home.

Although the study cautioned against an exact definition of sustainability because almost two-thirds (64%) of respondents were unsure what the term meant, consumers still want to know that travel brands are making a conscious effort to protect natural resources.

Some 65% of self-identifying sustainable travellers are sceptical of a brand's sustainability claims, the survey revealed, although twice as many (27%) believe claims made by reputable travel operators compared with non-sustainable travellers (12%).

The survey also showed that sustainable travellers are between 38% and 57% more likely to book travel with brands based on their sustainable practices compared to 11% to 21% of non-sustainable travellers. These practices include activities, such as donating profits to local communities or conserving natural resources.

Of particular note for brands seeking to tap into this growing market, the study found that sustainable travellers are mainly millennials in their 20s and 30s with annual incomes of $75,000 or more.

These consumers take several trips per year and they also spend more than the general leisure travel population, outspending general US leisure travellers on accommodation, air fares, dining and shopping. They spent an average of $600 more on their last trip than other travellers.

Commenting on the report, Brian Mullis, founder and CEO of Sustainable Travel International, said: "Historically people have said sustainable travel is a niche within the travel industry, but that's not true anymore. You have so many CEOs talking about it and many brands want a piece of it."

Data sourced from Skift; additional content by Warc staff