The oceans absorb carbon dioxide and play a critical role in reducing global warming. However, according to a study by The University of Texas at Austin, as the oceans continue to warm in the future, their ability to absorb CO2 will decline, leading to more severe warming. The study’s climate simulation suggests that the oceans’ maximum capacity to absorb CO2 will be reached by 2100 and will drop to half of its current efficiency by 2300 under a worst-case emissions scenario.
Although the emissions scenario used in the study is unlikely because of global efforts to limit greenhouse gas emissions, the findings reveal a previously unknown tipping point that if activated would release an important brake on global warming, the authors said. According to the findings, the effect begins with extreme climate change, which supercharges rainfall and slows ocean currents. This leaves the surface of the oceans covered in a warm layer of fresh water that won’t mix easily with the cooler, more alkaline waters below it. As this surface layer becomes more saturated with CO2, its alkalinity falls and with it, its ability to absorb CO2. The end result is a surface layer that acts as a barrier for CO2 absorption.