Before the Ice Maximum
At this point Ireland was not the green, wooded island familiar today. It lay within the north-west European glacial world, exposed to severe climatic swings and profoundly altered sea levels. The Last Glacial Maximum proper came later: current syntheses place the last major advance of the Irish Ice Sheet broadly between about 27,000 and 23,000 calibrated years BP, although the timing and extent of ice varied markedly between regions. The British-Irish Ice Sheet was not a fixed white blanket that arrived everywhere at once. Its margins, flow routes and thickness altered over millennia, responding to climate, topography and the dynamics of fast-flowing ice streams.