"Photo: Tom Schifanella, USA: ""Since 2000, Icelandic glaciers have lost 12% of their size, in less than 15 years. Pictured here, Icelandic guide Hanna Pétursdóttir admires an ice cave inside the Svínafellsjökull Glacier, which she notes is rapidly expanding due to the effects of global warming,"" wrote Schifanella. <em>Via National Geographic Your Shot</em>"