Thursday, April 2, 2015
Maybe one of the most interesting and potentially drastic climatic events is the possibility of a “Gulf Stream” or Thermohaline Circulation shutdown. The North Atlantic Drift is the northwards continuation branch of the Gulf Stream, part of the Thermohaline circulation (THC). The North Atlantic Drift transports warmth further north to the North Atlantic, where its effect in warming the atmosphere contributes to warming Europe. Without this warmth “imported” from southern latitudes by the North Atlantic Drift , most of western Europe would be much colder than it is, similar locations at the same latitude such as Alaska, Northern Canada and Siberia. It is thanks to this current that Ireland only gets a bit of snow for a day or two along most of its coast rather than spend all winter under several feet of snow. England, France and most of western and northwestern Europe benefit greatly from it as well.
Trying to explain it in simple terms, the THC basically works thanks to changes in density and salinity in ocean waters. In the north Atlantic, low temperatures combined with high evaporation rates thanks to the strong winds increase the density of the surface water. Because of this, the surface water sinks drawing in warmer waters from the south in what is sometimes called the “ocean conveyor belt.”
So… what’s the problem?
The problem is that, by all accounts, this changing. One theory is that due to increased precipitations and the melting of glaciers in Greenland there’s a greater amount of freshwater in the northern oceans, reducing its salinity.
In November 2005, the National Oceanography Centre in the UK found a 30% reduction in the warm currents that carry water north from the Gulf Stream from the last such measurement in 1992. Also in 2005, Peter Wadhams reported in The Times of London about the results of investigations in a submarine under the Arctic ice sheet measuring the giant chimneys of cold dense water, in which the cold dense water normally sinks down to the sea bed and is replaced by warm water, forming one of the engines of the North Atlantic Drift. He and his team found the chimneys to have virtually disappeared. Normally there are seven to twelve giant columns, but Wadhams found only two giant columns, both extremely weak.
Scientists are divided on how fast this is happening or not and they are also divided on the consequences of the potential slowdown or even shutdown of the North Atlantic Drift (NAD). Some scientists claim that even if the NAD slows down or stops entirely, the effects of global warming would more than compensate for it and there would be little to no change, maybe even slightly warmer temperatures than before. On the other hand some scientists believe is could trigger a new glacial period, even a series of Dansgaard-Oeschger events with very rapid changes, temperatures dropping significantly in a matter of months in dramatic fashion somewhat similar to the movie “The Day After Tomorrow”.
A worst case scenario such as this one has happened before. It happened about 10.000 years ago, called Younger Dryas stadial, also known as the Big Freeze... yes, its the kind of thing that would ruin your weekend. In this case, the prevailing theory is that the Younger Dryas was caused by significant reduction or shutdown of the North Atlantic "Conveyor", which circulates warm tropical waters northward.
As interesting as it may be, there’s not much practical application in debating if this is a natural event or if it’s all some conspiracy to deviate funds to eco-business. At this point from a survival perspective we should be looking more into how quickly this can all go down, if it’s a matter of centuries, decades or years, and the level of magnitude we are talking about. Based on the research published so far, I would lean towards the theory that this is all happening surprisingly fast. At the same time and on a more positive note, I don’t think we’ve seen much changes in temperatures in western Europe, at least not anything to worry much about. Other than somewhat more precipitations than usual, the peaks of both cold and warm averages and maximum are still within historic parameters. We’ve seen winters just as cold if not colder, and we’ve seen days just as warm as well. You could make a case for winters lasting slightly longer and being in average colder, and that there’s more rain and storms, but even if it is happening, so far the difference is not proportional to the reduction of the North Atlantic Drift.
I would recommend caution, but at the same time keeping an eye on weather changes in the years to come, especially in western Europe and northeastern US.
As always, having plans to eventually relocate if necessary is always a good idea.
Fernando “FerFAL” Aguirre is the author of “The Modern Survival Manual: Surviving the Economic Collapse” and “Bugging Out and Relocating: When Staying is not an Option”.