Monaco: Two days after a climate summit failed to deliver game-changing pledges to slash carbon emissions, the United Nations warned Wednesday that global warming is devastating oceans and Earth's frozen spaces in ways that directly threaten a large slice of humanity.

Crumbling ice sheets, rising seas, melting glaciers, ocean dead zones, toxic algae blooms a raft of impacts on sea and ice are decimating fish stocks, destroying renewable sources of fresh water, and incubating superstorms that will ravage some megacities every year, according to a landmark assessment approved by the 195-nation Intergovernmental Panel on Climate Change (IPCC).