Last year was among the hottest ever recorded on the planet, and the oceans’ temperature reached a historic high — yet another sign of the worsening climate crisis caused by humans.In a report released Thursday by the National Oceanic and Atmospheric Administration, scientists found that 2021 was the sixth-warmest year on record. Overall, the past eight years have been the hottest years since record-keeping began in 1880, according to a similar analysis released Thursday by NASA. Earth’s average land and ocean surface temperature was 1.5 degrees Fahrenheit above the 20th century average.And temperatures in the world’s oceans reached a record high. High ocean heat can contribute to sea-level rise, NOAA said, and cause more-severe storms and floods. “Science leaves no room for doubt: Climate change is the existential threat of our time,” NASA administrator Bill Nelson said in a news release. The year-after-year temperature highs for the planet “[underscore] the need for bold action to safeguard the future of our country – and all of humanity,” he said.NASA’s scientists pointed clearly to the cause of the worsening climate crisis: “human activities that have increased emissions of carbon dioxide and other greenhouse gases into the atmosphere.” A storm-damaged house in September after Hurricane Ida hit Louisiana. Sean Rayford via Getty ImagesGlobal warming fuels deadly climate disasters, including intense droughts, extreme heat, worsening wildfires and more-powerful storms and floods. In 2021, Earth experienced the hottest July ever (again), the largest-ever single wildfire in California history (again), and deadly hurricanes and flooding along the Gulf of Mexico and on the Atlantic coast in the U.S. (again).