And now for some good news. From the journal Science, June 11:
Shifting currents
Off the coast of the Canary Islands—In calm waters here off the northwestern coast of Africa, the crew of the RRS Discovery, a U.K. research ship, was scanning the horizon, waiting for a sentinel to return from the deep. An acoustic ping had triggered the release of a mooring holding 2 years of precious ocean measurements from its anchor 2000 meters below. More than 20 minutes had elapsed, and there was still no sign of the bright orange float that would lift the mooring to the surface. But Ben Moat, the cruise’s chief scientist and an oceanographer at the United Kingdom’s National Oceanography Centre (NOC), wasn’t worried. He had been here before.
On the bridge, Moat glanced at a black Casio watch attached to his clipboard: 22 minutes. There was more competition than usual to be the first to spot the float. Moat, the captain, and the third officer were joined by NOC’s CEO, as well as several members of a U.K. TV news crew. “Is it still off to port?” Moat asked, peering through binoculars for a mote of orange against a sea of azure.
The crowd on the bridge reflected the importance of the mooring, one of 10 in a vital climate observatory called the RAPID array. For more than 2 decades, RAPID’s instrument-packed moorings, spaced across the Atlantic Ocean at 26°N between the Bahamas and the Canary Islands, have monitored the changing strength of ocean currents called the Atlantic Meridional Overturning Circulation, or AMOC. The currents usher tropical waters and heat to the northeastern Atlantic, allowing cabbage palms to flourish in Ireland and keeping Norwegian ports ice-free in winter. As the waters move north, they cool and become saltier as sea ice forms and rejects brine. The resulting cold, salty water becomes dense enough to sink to the abyss, carrying heat and carbon dioxide down with it. The water returns south along the floor of the Atlantic, heading to the Southern Ocean and beyond.
Climate models have long warned that global warming could weaken “deep-water formation”—the density-driven sinking that is the engine of the AMOC. The logic is straightforward: As Greenland’s ice sheets melt and sea ice formation declines, North Atlantic waters will freshen. Combined with warmer sea temperatures, the freshening makes surface waters more buoyant. The AMOC was thought to have shut down abruptly during past climate warmings, and a handful of researchers now argue such a tipping point could occur this century. A sputtering AMOC could trigger a sharp cooldown in northwestern Europe, rising seas along the U.S. east coast, and shifts in tropical rainfall. “It is a risk that would really have severe impacts,” says Stefan Rahmstorf, a climate scientist at Potsdam University and a prominent voice warning of the threat.
Yet for all the alarming headlines, most climate researchers think the AMOC is more resilient than these worst case scenarios make it seem. Emerging evidence suggests the AMOC may not have actually collapsed in the warm climates following ice ages. More detailed climate models suggest it could weaken but not collapse in the current surge of warming. And studies of the AMOC’s present behavior do not yet show any clear signs of trouble. They’re also exposing new facets of the circulation that could buffer any eventual weakening.
“The paradigm has been, if we warm and freshen these areas, we’ll get less dense water and AMOC will slow down,” says Susan Lozier, an oceanographer at the Georgia Institute of Technology. “That paradigm isn’t holding up.”....
....MUCH MORE
If interested see also:
October 2013 - A Table From The UN's IPCC AR5 Climate Change ReportJust some off the cuff factoids, we'll put it together into a coherent (I hope) investment framework between now and the big Paris meeting coming up in 2015.
If you are going to bet real money on this stuff, learn everything and trust no one....
The Arctic ocean is weird.
Because of the basin shape and the fact that, whereas in most of the rest of the oceans the temperature gradients, the thermoclines, play the biggest role in mixing/non-mixing of various waters, in the Arctic it's the halocline, the salinity gradient that you have to pay attention to.
And then there are the currents....
From the American Geophysical Union's EOS...
Your financial counsel should be able to immediately answer this query upon being awakened from the deepest delta-wave slumber at 3:30 in the AM. Try it tomorrow. Go to his/her/ze/zir's house and scream the question.
If he/she/ze/zir can't return the correct response the charlatan should be subjected to an unmerciful dressing-down. Or worse....
