1) Climate change is the defining human development issue that threatens to undermine efforts to reduce poverty and limit human progress by eroding freedoms and choices. 2) The impacts of climate change are already being felt disproportionately by the world's poorest populations through increased extreme weather events and water scarcity. 3) Failure to adequately address climate change through ambitious emissions reductions and investments in adaptation could reverse generations of progress on human development goals for hundreds of millions of the world's poorest people.