Last year was the hottest on record for the ocean, an upward trend only expected to continue as it wreaks havoc on coastal communities and spurs irreversible losses to marine ecosystems. Ocean warming has cascading effects, melting polar ice and causing sea-level rise, marine heat waves and ocean acidification, the United Nations’ panel of climate experts made clear on Monday. Sea-level rise has doubled in the last three decades, reaching a record high in 2021, the Intergovernmental Panel on Climate Change (IPCC) reported. Rising seas, coupled with more extreme weather, are setting the stage for a perfect storm of flooding for coastal communities.