Pool of Arctic meltwater could change global ocean circulation patterns, and more

Scientists are concerned that melting water in the Arctic Ocean could change global ocean circulation patterns, alter climate and decimate marine fisheries.

Freshwater is accumulating in the Arctic Ocean due to recent increases in melting ice, and scientists are concerned about the impacts this “massive, growing pool” of meltwater would have if it were to flow out into the North Atlantic Ocean. An influx of freshwater in the North Atlantic Ocean could change global ocean circulation patterns, alter climate and decimate marine fisheries.

In a press release from April 5, 2011, Oceanographer Laura de Steur of the Royal Netherlands Institute for Sea Research explained that clockwise winds over the Arctic have largely contained the icy meltwater in an area of the Arctic Ocean known as the Beaufort Gyre. However, shifts in atmospheric circulation patterns could put an end to Arctic meltwater containment.

Breakdowns in the clockwise wind patterns over the Arctic have occurred as recently as the 1960s and the 1990s.

Thermohaline circulation. Image Credit: Wikimedia Commons

Located within the North Atlantic Ocean is a giant conveyor belt of circulating water. As warm water flows north from the equator, freshwater continuously evaporates leaving behind a cold and salty mass of water that is very dense. When the dense sea water reaches southern Greenland it sinks and drives strong southerly currents along the seafloor. This process is known as thermohaline circulation.

Thermohaline circulation in the Atlantic is critical for drawing equatorial heat into northern regions and for delivering nutrients from the north to marine food webs further south.

If excessive amounts of meltwater from the Arctic Ocean were to enter the North Atlantic, salinity levels would drop and the sinking water mass would become less dense and sink at a slower rate. Such a change in Atlantic thermohaline circulation could cause substantial cooling in northern countries and severely disrupt marine life and fisheries.

A disruption of Atlantic thermohaline circulation was the premise behind the 2004 disaster film “The Day After Tomorrow.” The film chronicles the rapid transformation of Earth’s climate into an ice age. Scientists are quick to note that the film is an over-dramatization and that any alterations in ocean circulation would likely impact climate more gradually over time.

Currently, climate models predict a 20 percent weakening of Atlantic thermohaline circulation by the end of the 21st century. While this prediction may not be good fodder for a Hollywood movie, the prospect of altered Atlantic circulation and the impacts that could ensue rank among the most worrisome of climate change scenarios for several hundred of Europe’s climate scientists.

Project CLAMER (Climate Change and European Marine Ecosystem Research) is an ambitious collaboration of 17 scientific institutions from 10 European countries that aims to inventory and synthesize findings from EU funded research projects on climate change and marine resources over the past 13 years.

In the press release, Carlo Heip, General Director of the Royal Netherlands Institute for Sea Research – the institution that coordinates project CLAMER – states:

There is a gap between what is known through research and what policy makers and the public know and understand about the impacts of climate change on the oceans.

Project CLAMER intends to help fill that gap so that people may act accordingly to reduce impacts and adapt to forthcoming climate changes.

Project CLAMER’s synthesis report will be released at an international conference at the Royal Flemish Academy of Belgium, Brussels on September 14-15, 2011. The report will explore in detail how physical changes in the oceans can disrupt marine ecosystems and cause negative economic and social impacts on Europe.

Jan Mees, Director of the Flanders Marine Institute and project CLAMER participant drives home the importance of the synthesis report when he states in the press release:

We know there is potential for substantial change, with wide-ranging impacts. We must both learn more and disseminate the knowledge in hand. Greater awareness is our best hope for motivating attempts to slow climate change and prepare for what it will bring.

I certainly will be looking forward to hearing more about project CLAMER’s synthesis report on climate change and marine resources to be released in fall 2011 – and I hope that you will too! In the meantime, as summer of 2011 approaches, many will be watching how much more ice will melt in the Arctic.

Deanna Conners