An anonymous reader quotes a report from The Guardian: The world's oceans have failed a key planetary health check for the first time, primarily due to the burning of fossil fuels, a report has shown. In its latest annual assessment, the Potsdam Institute for Climate Impact Research said ocean acidity had crossed a critical threshold for marine life. This makes it the seventh of nine planetary boundaries to be transgressed, prompting scientists to call for a renewed global effort to curb fossil fuels, deforestation and other human-driven pressures that are tilting the Earth out of a habitable equilibrium. The report, which follows earlier warnings about ocean acidity, comes at a time of recordbreaking ocean heat and mass coral bleaching.

Oceans cover 71% of the Earth's surface and play an essential role as a climate stabilizer. The new report calls them an "unsung guardian of planetary health", but says their vital functions are threatened. The 2025 Planetary Health Check noted that since the start of the industrial era, oceans' surface pH has fallen by about 0.1 units, a 30-40% increase in acidity, pushing marine ecosystems beyond safe limits. Cold-water corals, tropical coral reefs and Arctic marine life are especially at risk. This is primarily due to the human-caused climate crisis. When carbon dioxide from oil, coal and gas burning enters the sea, it forms carbonic acid. This reduces the availability of calcium carbonate, which many marine organisms depend upon to grow coral, shells or skeletons.

Near the bottom of the food chain, this directly affects species like oysters, molluscs and clams. Indirectly, it harms salmon, whales and other sea life that eat smaller organisms. Ultimately, this is a risk for human food security and coastal economies. Scientists are concerned that it could also weaken the ocean's role as the planet's most important heat absorber and its capacity to draw down 25-30% of the carbon dioxide in the atmosphere. Marine life plays an important role in this process, acting as a "biotic bump" to sequester carbon in the depths. In the report, all of the other six breached boundaries -- climate change, biosphere integrity, land system change, freshwater use, biogeochemical flows, and novel entities -- showed a worsening trend. But the authors said the addition of the only solely ocean-centerd category was a alarming development because of its scale and importance.

NASA aims to launch its first crewed lunar mission in over 50 years, as early as February. The 10-day Artemis II mission will send four astronauts on a lunar flyby to test systems, paving the way for future Moon landings under the Artemis program. The BBC reports: Lakiesha Hawkins, Nasa's acting deputy associate administrator said it would be an important moment in the human exploration of space. "We together have a front row seat to history," she told a news conference this afternoon. "The launch window could open as early as the fifth of February, but we want to emphasize that safety is our top priority." Artemis Launch Director, Charlie Blackwell-Thompson explained that the powerful rocket system built to take the astronauts to the Moon, the Space Launch System (SLS) was "pretty much stacked and ready to go." All that remained was to complete the crew capsule, called Orion, connected to SLS and to complete ground tests.

The Artemis II launch will see four astronauts go on a ten-day round trip to the Moon and back to the Earth. The astronauts, Reid Wiseman, Victor Glover, and Christina Koch, of Nasa and Jeremy Hansen of the Canadian Space Agency, will not land on the Moon, though they will be the first crew to travel beyond low Earth orbit since Apollo 17 in 1972. The lead Artemis II flight director, Jeff Radigan explained that the crew would be flying further into space than anyone had been before. "They're going at least 5,000 nautical miles (9,200Km) past the Moon, which is much higher than previous missions have gone," he told reporters. Further reading: NASA Introduces 10 New Astronaut Candidates