Climate change is taking a terrible toll on the century-old Zittel hut on top of a snow-capped mountain high in the Austrian Alps. Experts say warmer temperatures across the Alps accelerate glacier melt and thawing permafrost, with the consequences putting more pressure on the often ageing and neglected huts. The Zittel refuge shares the summit with the Sonnblick observatory, which has been measuring and documenting the changes to climate since it opened in 1886. "We really have a critical situation here in terms of the rate at which temperatures are increasing," says observatory head Elke Ludewig. IMAGES AND SOUNDBITES