This year's theme is Mountains under Pressure: climate, hunger, migration.

Almost one billion people live in mountain areas, and over half the human population depends on mountains for water, food and clean energy. Yet mountains are under threat from climate change, land degradation, over exploitation and natural disasters, with potentially far-reaching and devastating consequences, both for mountain communities and the rest of the world.

Mountains are early indicators of climate change and as global climate continues to warm, mountain people — some of the world’s hungriest and poorest — face even greater struggles to survive. The rising temperatures also mean that mountain glaciers are melting at unprecedented rates, affecting freshwater supplies downstream for millions of people. Mountain communities, however, have a wealth of knowledge and strategies accumulated over generations, on how to adapt to climate variability.

Climate change, climate variability and climate-induced disasters, combined with political, economic and social marginalization, increase the vulnerability of mountain peoples to food shortages and extreme poverty. Currently, about 39 percent of the mountain population in developing countries, or 329 million people, is estimated to be vulnerable to food insecurity.

As the vulnerability of mountain populations grows, migration increases both abroad and to urban centres. Those who remain are often women, left to manage the farms but with little access to credit, training and land tenure rights. Out-migration from mountain areas will also result in an inestimable loss in terms of provision of ecosystem services and preservation of cultural and agrobiodiversity. Investments and policies can alleviate the harsh living conditions of mountain communities and reverse out-migration trends from mountain areas.

International Mountain Day 2017 provides an occasion to highlight how climate, hunger and migration are affecting highlands and to ensure that sustainable mountain development is integrated into the 2030 Agenda and in the implementation of the Paris Agreement.

This year, the theme is also linked to the Mountain Partnership Global Meeting, to be held on 11-13 December at FAO headquarters in Rome, Italy, which will focus on the challenges and opportunities in sustainable mountain development and will launch a Framework for Action to support concrete actions and establish policies that strengthen the resilience of mountain peoples and environments.