Melting of the Greenland ice cap may affect future stability of ocean circulation

Melting of the Greenland Ice Cap could seriously affect the future stability of ocean circulation, according to the findings by Dr Rainer Zahn, research professor in the ICREA at the UAB Institute of Environmental Science and Technology (ICTA).

Washington, May 8 : Melting of the Greenland Ice Cap could seriously affect the future stability of ocean circulation, according to the findings by Dr Rainer Zahn, research professor in the ICREA at the UAB Institute of Environmental Science and Technology (ICTA).

According to the study, the magnitude of possible climate change in the future will depend to a large degree on the response of ocean circulation to global warming.

As the ocean currents distribute an immense quantity of heat around our planet and also determine levels of humidity and energy, any variation in ocean circulation may lead to substantial and abrupt climate changes on a global scale, the study said.

"Deep ocean sediments offer a record of ocean circulation in the past. By studying these sediments, we can see that abrupt changes in ocean circulation and the subsequent climate change are not a new phenomenon, but have happened on several occasions in the past. When the great ice sheets covering North America and Scandinavia melted at the end of the last ice age, the subsequent flow of fresh water into the North Atlantic caused the greatest natural disturbance in ocean circulation in the last 20,000 years," the study said.

"This episode provides an excellent model to examine the relation between ocean disturbance and climate instability," it added.

According to the study in the journal Science, ocean circulation during the last ice age was very different to present day circulation.

The formation of deepwater currents in the North Atlantic was much weaker. The flow of warm water from the Gulf Stream decreased, which in turn, led to a cooling of the northern hemisphere and contributed to the formation of the great ice caps which covered North America, Scandinavia and Europe.

In a similar study, the marine sediments of the North Atlantic were observed in order to document the sequence of events that led to that disturbance.

The melting caused a significant decrease in the Gulf Stream, which transports warm water from the Gulf of Mexico to the North. This submerged the region of the North Atlantic into a period of glacial cold, which lasted at least 1,200 years, the study said.

Scientists said disturbances caused by melting might also cause substantial changes in ocean circulation without the need for a catastrophic dumping of fresh water.

This seems to indicate that an acceleration in the melting of the Greenland ice cap, could, in fact, play a key role in the future stability of ocean circulation and climate change in the whole North Atlantic region, Dr Zahn said.

ANI