i'm travelling with professor david vaughan, the director of science at the british antarctic survey.for five hours, i get my first glimpse of antarctica, snow and ice stretching as far as the eye can see. finally, our destination. we are heading to mcmurdo. which is pretty much straight off over there. it is the last fingerhold of civilisation, the most southerly town on earth, and the largest centre for scientific research on the continent. and, out across the sea ice, the first peaks of the mighty tra nsa ntarctic mountains. keep it staying in place... it is here in mcmurdo that our expedition to the thwaites glacier begins. so thwaites glacier is vulnerable, and there is nothing stopping a collapse once it really takes hold. thwaites glacier is the size of britain and already accounts for 4% of global sea level rise. the fear is, if the melt rate increases, much of the west antarctic ice sheet could go, too. that could raise world sea levels by more than three metres. why is the glacier changing? why is it being eaten away? it's being eaten away because there are winds on the ocea

i'm travelling with professor david vaughan, the director of science at the british antarctic survey.g due south for five hours, i get my first glimpse of antarctica, snow and ice stretching as far as the eye can see. finally, our destination — mcmurdo. we are heading to mcmurdo, which is pretty much straight off over there. it is the last fingerhold of civilisation, the most southerly town on earth, and the largest centre for scientific research on the continent. and, out across the sea ice, the first peaks of the mighty tra nsa ntarctic mountains. keep it staying in place... it is here in mcmurdo that our expedition to the thwaites glacier begins. so thwaites glacier is vulnerable, and there is nothing stopping a collapse once it really takes hold. thwaites glacier is the size of britain and already accounts for 4% of global sea level rise. the fear is, if the melt rate increases, much of the west antarctic ice sheet could go, too. that could raise world sea level worldwide by more than three metres. why is the glacier changing? why is it being eaten away? it's being eaten away beca