Mountain areas cover close to a quarter of the Earth's land surface; they provide essential ecosystem goods and services and are water towers for billions of people living downstream. Nevertheless, the mountain agenda has not yet been addressed adequately by the UNFCCC climate deliberations and associated processes to reflect the need to improve and maintain mountain ecosystem services. The Prime Minister of Nepal, at UNFCCC COP 15, called on all the mountain countries and stakeholders to come together to a common platform of a 'Mountain Initiative for Climate Change Adaptation in Mountainous Regions' to ensure that mountain concerns get due attention in the climate change deliberations. The present paper (prepared jointly by ICIMOD and the Government of Nepal) provides a rationale and framework for the Mountain Initiative. It describes the context of the Initiative, elaborates the specific vulnerability of mountain people and the mountain environment, and highlights the importance of mountain ecosystem services for both mountain people and downstream communities. Finally, it calls for all stakeholders to develop a common vision and strong voice to ensure that mountain concerns are represented in future COP negotiations and there is more concrete support towards adaptation to global changes.