Marine heatwaves may become more intense, frequent, say scientists
The mixed layer of the ocean which blankets the top 20 to 200 meters is becoming thinner each year, says a new study that warns that the continued loss of this buffer may lead to more frequent and destructive warming events such as marine heatwaves. The thickness of this top layer of the ocean is responsible for marine heat events.
The armor of the ocean is becoming thin: Scientists
The thicker the layer, the more it can act as a buffer to shield the water below from incoming hot air. According to the study, published in the journal Bulletin of the American Meteorological Society, the scientists found that this armor is thinning, causing heatwaves.
Less heat can warm ocean if mixed layer is thin
"Marine heatwaves will be more intense and happen more often in the future. When the mixed layer is thin, it takes less heat to warm the ocean more," said Dillon Amaya, lead author of the study. They used a combination of ocean observations and models to estimate the depth of the mixed layer back to 1980, and also project out into the future.
By 2100, the layer would have declined by 30 percent
Researchers found that over the last 40 years, layer has thinned by nearly three meters in some regions of the North Pacific. By 2100, they believe the mixed layer could be four meters thinner which is about 30 percent less than what it is today.
Drastic swings in ocean temperatures expected
The thin mixed layer combined with warmer global temperatures may lead to drastic swings in ocean temperatures, leading to more frequent heating events. "Think of the mixed layer as boiling a pot of water. It will take no time at all for an inch of water to boil, but much longer for a pot filled to the brim to heat through," Amaya said.
Fisheries and other coastal operations are in danger
Researchers also warned that as the climate continues to warm and the mixed layer continues to thin, scientists might lose the ability to predict annual ocean surface temperatures. Fisheries and other coastal operations could be in danger without this ability to accurately forecast ocean temperatures.
