Today, December 11th, is International Mountain Day, the United Nations' annual nod to the importance of mountain ecosystems and cultures.
Home to 15% of the world´s population, mountains also host about half the world's biodiversity hotspots. They provide fresh water to half of humanity, and their conservation has been identified as a key factor for sustainable development.
But around the world, mountain areas are under threat from climate change and overexploitation. As the global climate continues to warm, mountain people — some of the world's poorest — face even greater struggles to survive. The rising temperatures are also causing the loss of glaciers at unprecedented rates, affecting freshwater supplies downstream for millions of people.
A growing awareness of the importance of mountains led the UN to declare to 2002 the UN International Year of Mountains, and the first international day was marked in 2003. This year's theme is mountain biodiversity.
Mountain topography, compressed climatic zones and isolation create habitats for a huge variety of life. But climate change, unsustainable farming practices, mining, logging, and poaching all take a heavy toll on mountain biodiversity. Ecosystem degradation, loss of livelihoods and migration in mountains can lead to the abandonment of cultural practices and ancient traditions that have sustained biodiversity for generations, say the UN.
The sustainable management of mountain biodiversity has been increasingly recognized as a global priority.
The UN are inviting people to mark the day by passing on an environmental message, joining an event or just sharing a favourite mountain photo on social media using the hashtag #MountainsMatter.
In that spirit, we are sharing some of our favourite photos submitted by site users to the galleries in the last few months.