A recent study led by a British team of scientists has revealed that a thin layer of cool surface water, just under 2mm deep, significantly contributes to the ocean’s ability to absorb carbon dioxide. This groundbreaking finding was achieved after months of meticulous data collection during voyages across the Atlantic, where researchers measured gas and temperature levels with precision.
The scientists discovered that the slight temperature difference between the “ocean skin” and the underlying water creates an interface that enhances CO2 absorption. They employed sensitive equipment to monitor water temperatures and detect minute variations in the amount of CO2 in the air that is either entering or leaving the ocean’s surface.
Daniel Ford, a research fellow at the University of Exeter, emphasized the relevance of these findings in light of the upcoming COP29 climate change conference. “This work highlights the critical role of the oceans and should aid in refining the global carbon assessments that inform emission reduction strategies,” he stated.
Ford was part of the research expedition aboard the RRS Discovery, which journeyed between Southampton and Punta Arenas in Chile. He described the challenging conditions they faced, including rough seas in the North Atlantic and around the Falkland Islands, contrasting with the tranquil waters near the equator.
The 2mm layer of cooler water results from what scientists refer to as the “cool skin effect,” where heat escapes from the water as it interacts with the atmosphere. The study’s results, published in the journal Nature Geoscience, have been shared with the Global Carbon Budget assessment, a collaborative effort among scientists aimed at deepening the understanding of Earth’s carbon cycle.
Professor Jamie Shutler, an ocean and atmospheric scientist at the University of Exeter, noted that the ocean skin is marginally cooler than the layer below it, and this temperature difference plays a crucial role in CO2 absorption, driven by the concentration gradients of gases between the two layers. He mentioned that while the effects were first proposed in the early 1990s, the absence of field evidence had previously hindered progress.
Gavin Tilstone from the Plymouth Marine Laboratory added, “This discovery underscores the complexity of the ocean’s water column structure and how it affects CO2 drawdown. Grasping these subtle mechanisms is essential as we refine our climate models and predictions, highlighting the ocean’s critical role in maintaining the planet’s carbon cycle and climate.”
