This came as a surprise. For the past two years, I had reasonably assumed that the erosion of the arctic ice pack reflected heat input from the atmosphere and was perplexed at the complete lack of related climate behavior even just south of the arctic.
Here it is argued that we are dealing with a reordering of the surface salinity and that this was triggered by a change in the wind system. In short, instead of a major application of atmospheric heat we are having a minor application of winds whose direct effect is vastly in excess of the input energy in terms of output energetics.
This also introduces another prime cooling mechanism in the form of an overturn of salinity that is also able to explain the sudden onset of so called little ice age conditions.
There have been many warm periods in the northern climate. These all appear to have ended abruptly. I have entertained several other mechanisms to attempt to understand this phenomenon. Understand that it is the precipitous decline that gives us difficulties rather than the gentle warming trend.
I am not sure how sound this argument happens to be or how well supported by data. That this is the first I have heard of it surprises because that is evidence of a lack of general distribution or discussion. I need to see more related discussion. However it is a compelling argument and draws us into a much better explanation for the abrupt onset of cold weather in the North.
There had to be some reason that the Rhine froze and allowed the
Western Roman Empire to be overrun. It certainly cannot happen under our present understanding.
Thursday, September 24, 2009
It is modern myth that CO2 is melting the Arctic sea ice. No doubt many people will take immediate offence at the mere title of this post but they would do well to listen to the data before they jump. CO2 is supposed to heat the earth's atmosphere and then would melt the ice from above. The atmosphere can't get past the ice to warm the water below so the only logical conclusion is that a warm atmosphere should melt the ice from above.
But what is happening is the Arctic ice is melting from below due to warm waters that normally are about 100-200 m below the surface. I am going to show that due to a change in the winds, the
Let's start by looking at the vertical temperature profile of the
Note that about 200 meters beneath the sea surface, the water temperature is 2 deg C--well above the melting point. If that heat can get up to the surficial layer, past the fresh water, it would melt the ice. Since fresh water is less dense than salt water, the density difference is what keeps the warm water from the ice.
Now, the halocline, the layer of fresh water is about 50-100 meters thick. The ice above is only about 3 meters thick--people think the Arctic sea ice is hundreds of feet thick but it isn't (http://www.arctic.noaa.gov/essay.wadhams.html). What happened in the
Here is how this happened. Below is a comparison of the wind patterns in the 70s and 80s vs, the late 80s and 90s.
The left picture is 1979-1988; the right is 1989-1997. The big high pressure cell (red) present in the earlier times is gone in the later times. And that has had a big impact on the freshwater flow in the surficial waters of the
"This study was motivated by observations of significant salinification of the upper
The impact of that increased salinization is that the ice is no longer protected from the warmer waters below. Johnson and Polyakov state:
"The replacement of fresh surface waters with more saline waters reduced vertical stratification and increased heat flux, releasing heat from cold halocline layer to upper layers of the
Swift et al, say the same thing--that the heat from below is warming the ice above, melting it.
"The halocline is the principal density structure of the
Swift et al looked at records of temperature over the past 50 years looking for previous warming periods. They show a very interesting plot which shows the temperature structure of the
You can see that there were warm periods in the underlying water three times during the past, the early 1950s, the mid 1960s and the early 1970s.
What is happening in the
" We find that beginning about 1976, most of the upper
Now as long ago as 1998 it has been known that the warm waters beneath the ice was in direct contact with the ice, yet the global warming hysteriacs continue to ignore the scientific data
" Changes are also seen in other halocline types and in the Atlantic Water layer heat content and depth. Since the cold halocline layer insulates the surface layer (and thus the overlying sea ice) from the heat contained in the Atlantic Water layer, this should have profound effects on the surface energy and mass balance of sea ice in this region. Using a simple mixing model, we calculate maximum ice-ocean heat fluxes of 1–3 W m−2 in the Eurasian Basin, where during SCICEX'95 the surface layer lay in direct contact with the underlying Atlantic Water layer." Steele, M., and T. Boyd (1998), Retreat of the cold halocline layer in the
Remember that the warm underlying Atlantic water is in direct contact with the ice above and that this is due to the salinization of the Arctic water. Here is the history of the salinization of the
Clearly about the time that the Arctic ice began to melt, the sea became more salty. CO2 is not melting the ice; the underlying warm water coming into contact with the ice from beneath is what is melting the Arctic ice.
Why do the global warming hysteriacs NEVER, EVER tell you this? Is it because they simply are pushing a political agenda rather than real science?