Taranaki's stunning coast is also one of the fastest eroding coastlines in the world. Since 2000, photographer Pat Greenfield has walked it, documenting the impact of storms, earthquakes and erosion. She calls it a photographic and scientific journey of discovery - and it's been a sobering one for her. For example two of the rock stack formations that she calls the Three Sisters and Four Brothers, have been decimated by storms. A selection of her photographs of the Tongaporutu Coastline are on show at New Plymouth's Puke Ariki. Pat explains to Lynn Freeman why this stretch of northern Taranaki coastline means to much to her. Pat Greenfield's exhibition Impermanence - The Tongaporutu Coastline, A twenty year odyssey has just opened at Puke Ariki Library in New Plymouth.