in short: The reason why Earth’s oceans have been on a record-hot streak, according to the article, is due to a combination of factors, with the main culprit being the growing energy imbalance on Earth. This imbalance is driven by the increased trapping of heat by greenhouse gases, like carbon dioxide and methane, which leads to more energy being absorbed by the planet than is being released back into space. This has been exacerbated since 2010, when the disparity between absorbed and released energy has doubled, causing the oceans to warm at an accelerating rate.

Additionally, there are other contributing factors, including changes in the reflectivity of the planet. For example, the reduction in reflective aerosols, partly due to pollution control measures like those targeting shipping fuel emissions, has resulted in less sunlight being reflected back into space, allowing more heat to be absorbed by the ocean.

Together, these factors have led to the record-breaking ocean temperatures, which have had severe consequences, such as coral bleaching, stronger hurricanes, and shifts in weather patterns.