HATCHET: WINTER. By Gary Paulsen. Macmillan Pounds 9.99

CHILDREN OF THE WHEEL. By Pamela Scobie. Oxford University Press Pounds 5.99

The story of The Eden Mission might seem a little far-fetched until you recall the fate of Greenpeace’s Rainbow Warrior. The predicament of the Sea Shepherd - the ship on which this tale of environmental activism is centred - is very similar, down to the loss of life.

The story is simple. Six teenagers, with their teachers and a leading conservationist - modelled on David Bellamy, who has supplied an introduction - embark on a “conservation crusade” to the Antarctic via North and South America. They face continual hazards created by “the Organisation”, whose illegal trade in “furs and wildlife products” is threatened by the Sea Shepherd’s exploits.

Anthony Wall takes every opportunity to introduce factual information about the destruction of the planet, with emotive descriptions of the deaths of a tiger, a whale, a wolf, seals and sea birds - all due to human greed or stupidity. The environmental considerations are injected into the adventure story - which includes a mild love interest - in a clear, interesting way.

On the whole this works well, though when they have to react to a traitor in their midst the six teenagers could be Enid Blyton’s Famous Five. Similarly, the incident when the conservationist Ben Bellingham is saved from an assassin by a 35-foot anaconda stretches credulity.

Hatchet: Winter, the fast-moving sequel to Gary Paulsen’s Hatchet, is concerned with the fate of one individual in a harsh environment. To stay alive in the Canadian winter wilderness Brian, who has survived a plane crash, must create shelter, hunt and kill animals for food and maintain his will to live.

Some readers (particularly younger ones) might be disturbed by the descriptions of hunting - the slow death of a moose eaten alive by wolves is unsettling. The suffering which nature inflicts is something which Brian finds hard to come to terms with, for as Paulsen says, “it still bothered him to kill”.

In Children of the Wheel, the fears of environmental collapse expressed in The Eden Mission have become reality. Pamela Scobie also goes for shock tactics in the early chapters, in which the City culls congenitally imperfect children to reduce the population. When the Prime Thinker orders the removal of children with green eyes from society his daughter Cyndra - up to then a privileged child and something of a Violet Elizabeth Bott - is one of the first victims. She is removed to a wasteland where outcast boys and girls live in separate, enemy tribes. Both groups are raided by men who take the older children as slaves.

Cyndra proves to be a genius, who literally re-invents the wheel. This achievement, among others, restores her status: but it is now based on merit, rather than birth.

Unfortunately, after such a powerful beginning, the plot begins to wander. It all smacks of a post-apocalyptic film with a theme tune by Tina Turner. There is a chilling twist at the climax, but whether the symbolism on which it all hangs would be recognised by younger readers is debatable.

The realisation that, as a character in Children of the Wheel says, “everything is relying on everything else” seems crucial to all three novels.

The Eden Mission and Children of the Wheel would appeal to older adolescents. One 16-year-old girl who does not like to read was gripped by the opening of The Eden Mission. The simplicity of Hatchet: Winter - more of a “boy’s own story” than the other two - makes it more widely accessible.