Stronger Atlantic Ocean Currents With More Open Arctic Ocean

Part 4. The Narwhals' Tale of Rising Seawater and Sinking Ocean

On the bounding main, ocean currents are driven by wind, tides, density gradients, and planetary motion. The world turns to the East. Because of this rotation, currents will bend to the right, an ocean motion known as the Coriolis Effect.

When a land mass is encountered in the Northern Hemisphere, the waters will veer to the right (left in the Southern Hemisphere). The Equatorial Drift, winds, and water westward across the Atlantic set up the clockwise gyre of waters in the upper 100 meters, with the Gulf Stream flowing north and the Azores Current flowing south.

Another phenomenon set up by the Earth’s rotation is Kelvin waves. Stir a cup of coffee, and the swirling liquid does not stay flat; it wobbles or waves up and down. These are very fast-moving waves of low amplitude. Kelvin waves are contrarian; at the equator, they propagate to the east against the trade winds. Kelvin waves go counterclockwise in the northern hemisphere, using the coastline as a waveguide. As a result, coasts on the east side of the ocean receive more energy and wave action. West-facing harbors will often see more dramatic tides than harbors on the opposite shore.

Most of the ocean moves in the thermohaline circulation, which flows to different water densities. The pump house for the world’s ocean is located near the bottom, the Antarctic, where water is coldest and densest. In the ice-forming process, salt is extruded to increase the density of the surrounding waters. Surface waters become dramatically denser in the flash of a freeze and sink into Antarctic Bottom Water. Freezing seawater at the surface drives the deep ocean waters below.

The most dramatic impact of Climate Change is found at the North Pole. Once, the summer Arctic Ocean stayed mostly icebound, with 2.7 million square miles of ice. Since 1979, the summer ice extent has declined 13.4 percent per decade on average. Where once about a third of the Arctic Ocean was open, now it is about two-thirds ice-free.

The percent open Arctic Ocean in August varies yearly, with changes in summer rainfall on warmed adjacent lands, including the MacKenzie River watershed and the Yukon River delta. The more rainfall and river input, the more sea ice melts.

There’s more. With twice the open water in the Arctic Ocean during summers, there is a much greater volume of surface water freezing when winter arrives. This cold, extra-salty water is the densest in the world. This displaces and pushes the circulation of the world’s deep water masses. With more volume, the intermediate Arctic water mass moves counter-clockwise around the pole over the top of Greenland. The Arctic currents flow into the Greenland Sea and onto the Denmark Strait between Iceland and Greenland.

The Arctic water is a different color from the Atlantic water. Tristan Gooley noted this when sailing west in a thirty-two-foot yacht north of Iceland into Arctic water. There was a sudden and complete change of seawater color “from a typical dull and dark grey/blue to a much lighter greener color that approached turquoise.” The air turned cold. He wrote into the logbook, “This N wind has a bite to it.”

To the east of Iceland, across the “dull and dark water” of the Fram Strait, is Svalbard, an archipelago at the end of the road for the Gulf Stream. At least until 2007, when warm Atlantic Water surfaced for the first time and came ashore. The fjord ice on Svalbard is disappearing at great speed due to more heat from Gulf Stream water.

Atlantic Water that has warmed 2°C in the past 30 years streams poleward from Svalbard beneath the surface water into the Arctic Ocean. It veers right above Norway to course along Siberian shores. The Atlantic Water core temperature decreases as it moves cyclonically around the Arctic. Heat lost to surface waters above accelerates the melt of the polar ice cap. With less sea ice, expect more sinking, salty, dense water come winter.

Increasing greenhouse gases trap 1% more heat in the atmosphere, upsetting the balance. We call this global warming and, more recently, climate change. Energy must go somewhere as heat that once went into outer space. Energy is spent on extreme weather events, more extended droughts, more violent downpours, category 3 hurricanes going to category 5 in 24 hours (Maria and Irma, where category 5 hurricanes have four times the fury (energy) of category 4 hurricanes), heavier rainfalls, and more melting of sea ice.

Next: Narwhal Pursuit of Halibut to the Bottom of Baffin Bay

Part 5. The Narwhals' Tale of Rising Seawater and Sinking Ocean