I’VE just finished reading a thought-provoking book by that late great adventurer and anthropologist Thor Heyerdahl. Green was the Earth on the Seventh Day recalls the author’s time living like a native on a Polynesian island with his new young wife Liv.

They travelled for an extended honeymoon to Fatu-Hiva in 1937 only to find a traditional way of life already in decline, thanks largely to the influence of European traders who had brought entrancing new objects for the natives to admire and desire.

The traders also brought with them not so desirable white man’s diseases. Before the islands were ‘discovered’ there were no mosquitos, for example. But the insects came accidentally with the explorers, bearing diseases such as elephantiasis, which causes limbs and other bodily parts to swell to enormous size.

The Heyerdahls initially found Fatu-Hiva idyllic but soon became disillusioned as they realised they couldn’t live among the local people, who had largely abandoned their traditional lives in favour of harvesting copra to trade for western goods.

Although the couple spent most of their 18 months there living in isolation, some of the time in a cave, it was to prove a life-changing experience for Heyerdahl. In Fatu-Hiva, he first contemplated a way of proving the Polynesian islands had been populated from South America, leading to the famous – if arguably inconclusive - Kon Tiki expedition of 1947.

His Ploynesian experience was also prescient in another sense.

The Heyerdahls visited the barren island of Motane, which had lost all its water because previous inhabitants had cut down trees to make huts and boats and to burn for cooking.

Once the trees were gone, the ability of the landscape to attract and retain rainwater also vanished.

Heyerdahl pointed out something which 70 years later is only just being grasped in some political and business quarters - this could happen all over our planet if deforestation is not checked.