Warming Ocean Currents Affect Weather and Environment

If one can imagine looking at our globe from the South Pole end, one can observe the ocean currents circulating water across the oceans.

First one would notice a current all the way around the perimeter of the Antarctic. A surface current circulates clockwise but there is also a deep undercurrent in the same direction. Branches then lead off towards the different oceans, serving as a global conveyor belt mixing the waters.

A deep current pushes its way between the east coast of Africa and Madagascar emerging as the monsoon surface current across the Indian ocean to India before looping back to supplement another current along Africa’s west coast. This eventually crosses the Atlantic to form the Gulf Stream drift recrossing the Atlantic to warm Britain and southern Scandinavia. Currents also loop the Pacific.

In an early Islamic map the system is first clarified (Lapham’s Quarterly, Fall 2019, p.10). The currents serve as global arteries that redistribute heat, salt and carbon around the globe. Not available to Vasco da Gama, the northward West African current stalled his ships. Is it climate change now slowing the system, mitigating its tempering effects? It has slowed by about 15 percent in the last half-century.

One consequence is the worsening Indian Ocean dipole effect where contrasting sea-surface temperatures in the warmer western (Arabian Sea area) and cooler eastern end near Indonesia affect climate. This year has seen one of the strongest dipoles on record, a 2-C difference. The result is more storms for East Africa leading to cooler, wetter weather, while at the other end Australia suffers extreme heat and raging bush fires far worse than usual. No ordinary fire but a 50-meter high firewall engulfed the homes, according to a shocked homeowner in a vivid description of what happened. The uncontrollable fires continue with the hope they will burn themselves out.

The ocean warming is also killing the kelp beds in the waters by the island of Tasmania. Australia’s giant kelp beds are literally being cooked by the ocean. The kelp rising in 30-foot high stalks has been habitat for rare ocean life through recorded history. Once present along the whole length of Tasmania’s east coast, now little is left — just in the cooler waters bordering the southern tip.

And the effects of global warming are everywhere. The Arctic tundra’s permafrost is melting from Alaska through Russia’s Siberia. At 57 degrees Fahrenheit, Chicago has just experienced the second-warmest Christmas on record; i.e., since 1871; the day following was 56 F and the hottest December 26 ever. New Jersey’s winters are so warm, its lakes no longer freeze.

Fish follow their instincts but are also in trouble. When the water turns too warm, they move, collapsing known fisheries. Worse, an abrupt change can decimate numbers. Fisheries in widely separated countries such as Japan, Angola and Uruguay are affected.

While the Philippines suffers a dozen and more severe storms annually, this year it has been hit by Super-Typhoon Mangkut in September with winds gusting to 255 km/h (160 mph). That is equivalent to a Category-5 (most severe) Atlantic storm. Then on December 3, it was struck by Typhoon Kammuri, followed not long thereafter by Typhoon Phanfone … tragically on Christmas Eve and Christmas Day turning celebration into anguish. Aside from the loss of crops and damage to infrastructure, the typhoons kill dozens of people, if not more, and can displace hundreds of thousands who take time to repair their lives.

Climate change (or more accurately warming) and the weather and its consequences remain inextricably linked. So are we humans, the principal catalysts of this anthropocene age.