Small Island Developing States. A group of 51 small economies (including 12 LDCs), that are some of the most vulnerable countries to climate change in the world. It has been active and vocal since the negotiations that created the UNFCCC. Their common concerns include rising sea levels and the increasing number of extreme weather events. SIDS are among the least responsible for climate change, and are dependent on others to take significant international actions towards mitigation and adaptation. SIDS are members of the AOSIS negotiating group, which serves as their main body for lobbying in UNFCCC negotiations. The UNFCC hosts expert meetings on adaptation for SIDS, to help identify specific adaptation needs and concerns.