Short answers, pulled from the story.
Scientists estimate the ocean absorbs about 25% of all human-caused carbon dioxide emissions. The ocean also absorbs more than 90% of the excess heat that accumulates in the climate system.
Between pre-industrial times and the 2011-2020 decade, the ocean's surface heated between 0.68 and 1.01 degrees Celsius. The global ocean reached its warmest ever recorded temperature in 2022, surpassing the previous record set in 2021.
Before 1998, there were no mass coral bleaching events on the Great Barrier Reef. The first occurred in 1998, and between 2016 and 2020 there were three such events. A sustained seawater temperature increase of just 1-2 degrees Celsius above normal is sufficient to trigger bleaching, which can lead to coral death if prolonged.
Overall ocean oxygen concentrations declined an estimated 2% over 50 years from the 1960s. Oxygen minimum zones are expanding worldwide, and the ocean has lost oxygen throughout its water column from the surface down to 1,000 metres.
Bering Sea snow crab populations declined 84% between 2018 and 2022 as a result of fallout from the 2019-2021 Pacific Northwest marine heatwave, a loss of approximately 9.8 billion crabs.
The Atlantic Meridional Overturning Circulation (AMOC) is a major ocean current system that moves warm water northward along the Atlantic surface and cold deep water southward. Modern observations and paleoclimate reconstructions suggest it may have weakened since the preindustrial era. Climate projections assessed in 2021 indicate the AMOC is very likely to weaken further over the 21st century, with the North Atlantic being particularly vulnerable to the effects.