The profound impact of global warming extends far beyond the surface, reaching into the deepest recesses of the world's oceans. A recent study published in Nature Climate Change reveals that over the past 18 years, the amount of heat absorbed by the ocean has doubled. This phenomenon is particularly evident in the deep layers below 700 meters, where a significant portion of this heat has accumulated and continues to increase at an alarming rate.

Researchers have turned to historical data for insights into this modern-day issue. Led by Peter Gleckler from the Lawrence Livermore Laboratory in California, the team utilized information gathered during the pioneering voyage of HMS Challenger in the late 19th century. This British survey ship traveled extensively, covering nearly 130,000 kilometers and collecting valuable data on ocean temperatures and marine life. By comparing these historical records with contemporary measurements, scientists have estimated that since 1970, approximately 90% of the Earth’s excess heat from human-induced global warming has been absorbed by the oceans. This absorption has helped to explain the apparent slowdown in atmospheric temperature rise, but it also raises concerns about future climate impacts.

The findings underscore the critical role oceans play in regulating global temperatures. While the temporary storage of heat in the deep ocean may have slowed surface warming, experts warn that this effect is not permanent. Once the ocean's heat uptake stabilizes, the pace of global warming could revert to previous levels. Moreover, the retained heat within the ocean can influence weather patterns and contribute to extreme events like El Niño. This research serves as a reminder that addressing climate change remains an urgent and essential task, as the consequences extend well beneath the waves.