Atlantis, now showing at Chichester’s Minerva Theatre, is a powerful drama about climate change.

In a small coastal village in Wales, Bryn and Gwen learn they will be forced to abandon their cherished home in the face of rising seawater, with government action to stop the disaster looking unlikely.

Their crisis rekindles Gwen’s crusading spirit, cradled at the Greenham Common protests in the 1980s - a commitment inherited by her granddaughter Rhiannon.

But as the years pass, their passionate activism threatens to divide mother from daughter, sister from brother, husband from wife.

Emily White’s play, winner of the George Devine Award, follows four generations as they discover the cost of saving their home and the planet. It is directed by Guy Jones.

It is not for the faint-hearted, as to demonstrate powerful weather the sound effects shake the theatre and at one point the cast run off a darkened stage into the audience, carrying torches and screaming against the elements.

The language may also shock but it reinforces the fear that writer Emily White conveys, a planet at risk from rising carbon dioxide levels, enveloping heat and rising sea levels, with green valleys turning into deserts.

Cleverly, instead of putting such a major issue on a world scale, the author has chosen to illustrate the terror that might be coming by setting the drama in a Welsh beachside bungalow in 2011, where the family are aware it could one day be engulfed by the sea.

The family are grandfather Bryn (a moving and powerful performance by Richard Elfyn), his surreal wife Gwen (a captivating Vivien Parry), daughter Claire (the feisty and also moving Catrin Aaron), single mother-of-two Astrid (Sara Otung, outstanding, who grows from a young schoolgirl to a power source fighting against climate change) and her brother Phillip (Alfie Llewellyn, who skilfully goes from wild youth to caring family man).

Acting honours must go to the children who took part - Iris Dempsey, Rex Bamber and Benjamin Miglioli.

The main theme is Bryn’s worry his house will one day be swamped by the rising sea and he will be forced out without a penny of compensation. He vows he will be the last man standing and there is a very emotional scene at the end when he fights to keep that vow.

Gwen is the main activist, given to joining protests against climate change so much that she goes on hunger strikes while filling her grandchildren with stories of how the Earth has evolved over millions of years to now reach the danger point of extinction through climate change.

By 2039, years of heavy rain and thunderstorms have caused severe flooding, sea levels have risen and the bungalow is on the verge of being swept away. The family begins to flee, but Bryn, unable to accept his wife’s death, refuses to leave without her.

Director Guy Jones skilfully sustains the family’s fear throughout the play while allowing the flow of Welsh humour this powerful production needs.

Atlantis runs until August 15.

By Sheila Checkley