Ice Age Blob of Warm Ocean Water Discovered South of Greenland
Scientists have discovered and ice age blob of warm water sandwiched between two major ice sheets just south of Greenland. It turns out that a warm ocean surface temperature prevailed during that time, which may have affected patterns of warming nearby.
Extreme climate changes in the past ice core records show that Greenland went through 25 extreme and abrupt climate changes during the last ice age about 20,000 to 70,000 years ago. In less than 50 years the air temperatures over Greenland could increase by 10 to 15 degrees Celsius. However, the warm periods were short; within a few centuries the frigid temperatures of the ice age returned. That kind of climate change would have been catastrophic for us today.
Ice core records also show climate changes in the same period; however, they appear to be more gradual with less severe temperature swings.
At that time, the circulation of the Atlantic Ocean with currents such as the Gulf Stream regulated the transportation of heat to this area. Essentially, the surface currents transported heat from the southern and tropical Atlantic toward the North Atlantic-just like it does today.
During the ice ages, this circulation was assumed to work as a seesaw in the playground; it went up and down in opposite directions with an axis somewhere around the equator. The idea was that when it warmed in the north, it cooled in the south and vice versa. However, researchers may have found that another scenario occurred.
During the coldest periods of the last ice age, the Nordic seas were covered with a permanent layer of sea ice. The pump stopped transporting the heat northward and the heat accumulated in the southern oceans. However, the warming wasn't restricted to the south.
"Our results show that it continued all the way to Iceland," said Tine Rasmussen, one of the researchers, in a news release. "The warming was slow and gradual, and happened simultaneously in both hemispheres. Little by little the warm Atlantic water penetrated into the Nonrdic sea underneath the ice cover. It melted the ice from below. Once the ice was gone, the pump started up again, bringing additional warm water in to the Nordic seas. And we got a warmer period for 50 years."
The findings reveal a bit more about the ocean cycle and how things keep warm.
The findings are published in the journal Scientific Reports.