Hi Chiara,
Since someone already mentioned “Chasing Ice,” I’d like to recommend “Chasing Water” which is filmed by Peter McBride on the Colorado River (aka “The American Nile”) and what’s causing it to dry out…It was a film from the Banff Mountain Film Festival in 2012.
Also from this year’s selection are:
“Mountains in Motion”, which used time lapse to show the beauty of our mountain scape
http://vimeo.com/45941676
and “Crossing the Ice” about the expedition of two Australians and a Norwegian from the ‘shores’ of Antarctica to the South Pole…and back
http://casandjonesy.com.au/expeditions/crossing-the-ice/
In terms of data and environmental issues, there’s a website about tracking the Amazon’s health which I think is really intriguing:
http://infoamazonia.org/
Just a couple ideas!