Atlantis Online
November 25, 2020, 10:04:26 pm
Welcome, Guest. Please login or register.

Login with username, password and session length
News: Satellite images 'show Atlantis'
http://news.bbc.co.uk/1/hi/sci/tech/3766863.stm
 
  Home Help Arcade Gallery Links Staff List Calendar Login Register  

A Climate-Change Amplifying Mechanism


Pages: [1]   Go Down
  Print  
Author Topic: A Climate-Change Amplifying Mechanism  (Read 105 times)
Major Weatherly
Superhero Member
******
Posts: 4848



« on: January 24, 2010, 02:18:34 am »

A Climate-Change Amplifying Mechanism

ScienceDaily (Mar. 8, 2007) During the past ninety thousand years there were alternating hot and cold periods lasting several thousand years each which resulted in a modification of global oceanic circulation. With the help of paleoclimatic and paleooceanographic indicators, scientists at CEREGE1 have highlighted a feedback mechanism of ocean circulation on the climate which reinforces this heating or cooling. This mechanism relies on a close link between the circulation of the North Atlantic and the tropical hydrology of Central America. This study, published in the February 22, 2007 edition of the review Nature, should allow us to better understand and therefore better predict the effects of climate change on oceanic circulation.

In the past, major and rapid climatic variations which took place notably during the last glacial period (Heinrich period) disturbed ocean circulation. Climatic archives (marine and lake sediment, polar ice, stalagmites) show the close relationship existing between climatic variations and oceanic circulation. Changes in oceanic circulation in the North Atlantic have influence on a planetary level by affecting, in particular, the water cycle. These changes are accompanied by a shift in the climatic equator which separates the trade wind systems of the two hemispheres: southwards during cold events and northwards during hot ones.
Report Spam   Logged

Share on Facebook Share on Twitter

Major Weatherly
Superhero Member
******
Posts: 4848



« Reply #1 on: January 24, 2010, 02:18:57 am »

Central America, a narrow continental strip which separates the Atlantic and Pacific oceans, plays a key role in this system. On the Atlantic side surface waters evaporate, which increases salinity. The water vapour is transferred by the trade winds to the Pacific where it is deposited as rain, thus lowering salinity there. This enormous transfer of water (several hundred thousand cubic meters per second) maintains a contrast in salinity between the two oceans. The surface waters of the tropical Atlantic are then transported, via the Gulf Stream, towards the high latitudes where they warm the atmosphere before plunging into the abysses in the convection zones situated in the seas of Norway, Greenland and Labrador. The deep waters formed by this process then flow into the world ocean, purging the North Atlantic of part of its excess salt.

The scientists at CEREGE1 reconstituted the variations in surface water salinity in the area where the water vapour coming from the Atlantic is deposited. To do this they worked on the measurements taken in marine sediments collected in 2002 west of the Isthmus of Panama by the French oceanographic ship the Marion Dufresne. This study shows that the cold Heinrich periods correspond to increases in salinity in the east Pacific. This is synonymous to a decrease in the transfer of water vapour. By comparing their results to other studies done in the Atlantic sector and in South America, the scientists were able to describe a feedback mechanism which amplified the climatic disturbance. During cold periods the trade winds, loaded with humidity, migrated southwards. Unable to cross the Andes part of the rain, which would normally have lowered the salinity of the East Pacific, fell in the Amazon basin. This feedback had the effect of re-injecting rainwater into the Atlantic, thereby decreasing the ocean's salinity. This water was then transported to the higher latitudes, contributing to the weakening of deep oceanic circulation, thereby reinforcing the cooling above and around the North Atlantic.
Report Spam   Logged
Major Weatherly
Superhero Member
******
Posts: 4848



« Reply #2 on: January 24, 2010, 02:19:34 am »

Today, the fact that global warming could disturb the water cycle and lead to a slowing down of the North Atlantic circulation is a real subject of concern. Oceanographic data from the last 50 years suggest that hydrographic changes (temperature and salinity) as well as a lessening of the flow of water transported by certain surface and deep-sea marine currents have already occurred in the North Atlantic. The risk of an even greater variation of oceanic circulation by the end of this century or the beginning of the next needs to be taken seriously and actively studied.
Email or share this story:
| More

Story Source:

    Adapted from materials provided by CNRS, via EurekAlert!, a service of AAAS.

Need to cite this story in your essay, paper, or report? Use one of the following formats:
APA

MLA
CNRS (2007, March Cool. A Climate-change Amplifying Mechanism. ScienceDaily. Retrieved January 24, 2010, from http://www.sciencedaily.com­ /releases/2007/02/070226131713.htm

http://www.sciencedaily.com/releases/2007/02/070226131713.htm
Report Spam   Logged
Major Weatherly
Superhero Member
******
Posts: 4848



« Reply #3 on: January 24, 2010, 02:20:14 am »



Average rainfall variations, simulated by models, after a collapse of deep ocean circulation (increases in blue, decreases in red; from Stouffer et al. 2006). The dotted arrow shows the actual flow of water vapour. The solid arrows indicate the multiple flows (trade winds -> rivers -> marine currents) during a climatic anomaly. Crosses show the paleoclimatic study sites. (Credit: Copyright CNRS 2006)
Report Spam   Logged
Ulric Lyons
Full Member
***
Posts: 34


« Reply #4 on: May 31, 2010, 06:14:47 pm »


 A Heinrich event is a really cold and dry period, like the Older Dryas, look it up on Wikipedia.
I have the periodicity mapped astronomically to 4627.33ys, 3 of these periods goes from the Older Dryas to the Little Ice Age. Cold periods also happen at 1 quarter of this period, so the next cold nodes are from around AD2450 and a much wors one from AD3600. History shows that civilisation prospers in warm wet times, and falls in cold dry times. The future will be no exception unless we get our priorities right.

  I can map the last 8,000 years of climate change at a monthly level, the next 2,000 is not a problem.
http://landscheidt.auditblogs.com/2008/06/03/the-sunspot-cycle-and-c24/
   http://www.facebook.com/ulric.lyons
The modern warming is natural.
Report Spam   Logged
Allison
Superhero Member
******
Posts: 4489



« Reply #5 on: May 31, 2010, 06:22:16 pm »

Hi Ulric, and welcome to the forum. 

You do know that the sun was ruled out as the chief cause of global warming, don't you?

Study acquits sun of climate change
POSTED: 11:39 a.m. EDT, September 15, 2006


OSLO, Norway (Reuters) -- The sun's energy output has barely varied over the past 1,000 years, raising chances that global warming has human rather than celestial causes, a study showed on Wednesday.

Researchers from Germany, Switzerland and the United States found that the sun's brightness varied by only 0.07 percent over 11-year sunspot cycles, far too little to account for the rise in temperatures since the Industrial Revolution.

"Our results imply that over the past century climate change due to human influences must far outweigh the effects of changes in the sun's brightness," said Tom Wigley of the U.S. National Center for Atmospheric Research.

Most experts say emissions of greenhouse gases, mainly from burning fossil fuels in power plants, factories and cars, are the main cause of a 0.6 Celsius (1.1 Fahrenheit) rise in temperatures over the past century.


A dwindling group of scientists says that the dominant cause of warming is a natural variation in the climate system, or a gradual rise in the sun's energy output.

"The solar contribution to warming over the past 30 years is negligible," the researchers wrote in the journal Nature of evidence about the sun from satellite observations since 1978.

They also found little sign of solar warming or cooling when they checked telescope observations of sunspots against temperature records going back to the 17th century.

They then checked more ancient evidence of rare isotopes and temperatures trapped in sea sediments and Greenland and Antarctic ice and also found no dramatic shifts in solar energy output for at least the past millennium.

"This basically rules out the sun as the cause of global warming," Henk Spruit, a co-author of the report from the Max Planck Institute in Germany, told Reuters.

Many scientists say greenhouse gases might push up world temperatures by perhaps another 3 Celsius by 2100, causing more droughts, floods, disease and rising global sea levels.

Spruit said a "Little Ice Age" around the 17th century, when London's Thames River froze, seemed limited mainly to western Europe and so was not a planet-wide cooling that might have implied a dimmer sun.

And global Ice Ages, like the last one which ended about 10,000 years ago, seem linked to cyclical shifts in the earth's orbit around the sun rather than to changes in solar output.

"Overall, we can find no evidence for solar luminosity variations of sufficient amplitude to drive significant climate variations on centennial, millennial or even million-year timescales," the report said.

Solar activity is now around a low on the 11-year cycle after a 2000 peak, when bright spots called faculae emit more heat and outweigh the heat-plugging effect of dark sunspots. Both faculae and dark sunspots are most common at the peaks.

Still, the report also said there could be other, more subtle solar effects on the climate, such as from cosmic rays or ultraviolet radiation. It said they would be hard to detect.

Copyright 2006 Reuters. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.
--------------------------------------------------------------------------------

http://www.cnn.com/2006/TECH/science/09/15/global.warming.sun.reut/index.html
Report Spam   Logged
Ulric Lyons
Full Member
***
Posts: 34


« Reply #6 on: May 31, 2010, 06:44:53 pm »

Unfortunately, the orthodoxy is barking up the wrong tree as per usual. What relly matters as regards temperature change on earth, is the solar wind velocity, not TSI. Such that warmer North Hemisphere winters in recent years (not the last 2) are due to higher solar wind speed in those months;
http://www.solen.info/solar/coronal_holes.html
see all the months with high wind speed were hot.

More sunspots actually leeds to colder winters as they inhibit coronal holes;
http://wattsupwiththat.com/2010/05/15/hey-dude-where%E2%80%99s-my-solar-ramp-up/
http://wattsupwiththat.com/2010/05/05/suns-magnetics-coming-alive-again/

http://landscheidt.auditblogs.com/2008/06/03/the-sunspot-cycle-and-c24/

   http://www.facebook.com/ulric.lyons

Report Spam   Logged
Ulric Lyons
Full Member
***
Posts: 34


« Reply #7 on: May 31, 2010, 06:50:48 pm »


 There is really no such thing as global warming. Recent warming, and in the 1930`s, 1830`s, 1740`s etc.
is at higher N.Hemisphere lattitudes, and almost exclusively in and arond winter.
http://www.appinsys.com/GlobalWarming/
Report Spam   Logged
Ulric Lyons
Full Member
***
Posts: 34


« Reply #8 on: June 01, 2010, 06:47:10 pm »

Hi Ulric, and welcome to the forum. 

You do know that the sun was ruled out as the chief cause of global warming, don't you?

Yo Allison, hi,

The is more than one reason why I stepped over this way to talk about my works. If I have any deep connection with Atlantis, or knowledge from the past, I`ll let others be the judge of that. What I do claim though, is that I am doing myself justice, and doing what i am supposed to be doing.
That being to explain the natural variation of climate, by identifying its cause.
This being the positions of the planets in relation to the Sun.
From what I have discovered, I can plot monthly or even weekly temperature changes in any year back or forwards, for thousands of years.
My collegue, Piers Corbyn of weatheraction.com, is also a unique maverick, and we are both set to totaly revolutionise weather and climate science.
http://www.sunrisecelebration.com/sunrise-blog/?p=135
Report Spam   Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by EzPortal
Bookmark this site! | Upgrade This Forum
SMF For Free - Create your own Forum
Powered by SMF | SMF © 2016, Simple Machines
Privacy Policy