Millions of vulnerable people around the world are suffering from intensifying climate-related disruptions that could be construed as limits problems. Because those who suffer the most are often the most marginalized, these communities are largely neglected by governments and national media. In rich countries, social media has enabled ordinary citizens to add their voices to the public discourse. In the Global South, access to Internet and social media technologies is extremely constrained. In this paper, we study how, despite these barriers, communities in Bangladesh that are chronically affected by riverbank erosion are managing to use Facebook to participate in "hashtag activism." this activism makes some progress toward filling the information gap regarding the impacts of riverbank erosion in Bangladesh, and can inform the national media and government for taking action.