Saturday, October 07, 2006

SCIENTISTS PREDICT SOLAR DOWNTURN, GLOBAL COOLING

As we have already said here there are three states to the solar complex on off and both.It is intersting there are a substantial number of papers to be published on the inverse relationship of the solar complex,Phil Stott suggests a paradigm shift,this may be more of a scientific backlash of poor analysis of the astrophysics by climate scientists.This will provide some intersting debate in the coming months as the astrophysicts(Brazil) play the climate scientists(Andorra) in a robust game of celestial mechanics(football).

There is already discussion on this at the RAS sun-climate conferece in Russia last weekend,and debate forming in scientific literature here

It is known as the Little Ice Age. Bitter winters blighted much of the northern hemisphere for decades in the second half of the 17th century. The French army used frozen rivers as thoroughfares to invade the Netherlands. New Yorkers walked from Manhattan to Staten Island across the frozen harbour.
Sea ice surrounded Iceland for miles and the island's population halved. It wasn't the first time temperatures had plunged: a couple of hundred years earlier, between 1420 and 1570, a climatic downturn claimed the Viking colonies on Greenland, turning them from fertile farmlands into arctic wastelands.

Could the sun have been to blame? We now know that, curiously, both these mini ice ages coincided with prolonged lulls in the sun's activity - the sunspots and dramatic flares that are driven by its powerful magnetic field.
Now some astronomers are predicting that the sun is about to enter another quiet period. With climate scientists warning that global warming is approaching a tipping point, beyond which rapid and possibly irreversible damage to our environment will be unavoidable, a calm sun and a resultant cold snap might be exactly what we need to give us breathing space to agree and enact pollution controls. "It would certainly buy us some time," says Joanna Haigh, an atmospheric physicist at Imperial College London.

Global average temperatures have risen by about 0.6 °C in the past century, and until recently almost all of this has been put down to human activity. But that may not be the only factor at work. A growing number of scientists believe that there are clear links between the sun's activity and the temperature on Earth. While solar magnetic activity cannot explain away global warming completely, it does seem to have a significant impact. "A couple of years ago, I would not have said that there was any evidence for solar activity driving temperatures on Earth," says Paula Reimer, a palaeoclimate expert at Queen's University, Belfast, in the UK. "Now I think there is fairly convincing evidence."

What has won round Reimer and others is evidence linking climate to sunspots. These blemishes on the sun's surface appear and fade over days, weeks or months, depending on their size. More than a mere curiosity, they are windows on the sun's mood. They are created by contortions in the sun's magnetic field and their appearance foretells massive solar eruptions that fling billions of tonnes of gas into space. Fewer sunspots pop up when the sun is calm, and historically these periods have coincided with mini ice ages.

The number of sunspots and solar magnetic activity in general normally wax and wane in cycles lasting around 11 years, but every 200 years or so, the sunspots all but disappear as solar activity slumps (see "Field feedback"). For the past 50 years, on the other hand, the sun has been particularly restless. "If you look back into the sun's past, you find that we live in a period of abnormally high solar activity," says Nigel Weiss, a solar physicist at the University of Cambridge.

Fortunately, an indirect record of the sun's moods stretching back thousands of years has been preserved on Earth in the concentrations of rare isotopes locked into tree rings and ice cores. The story begins way out beyond the orbit of Pluto, at the boundary of the sun's magnetic field. While the sun is magnetically calm, its field extends around 12 billion kilometres into space, but the field puffs up to 15 billion kilometres when the sun is active. Cosmic rays - the high-energy particles from deep space that are constantly hurtling towards us - are deflected by the field, so at active times far fewer of them reach the Earth.


5 Comments:

Blogger sagenz said...

call me stupid but how can earth bound scientists tell the difference between solar activity and carbon dioxide activity on the basis of tree rings?

They cannot show both increased solar activity and the effect of increased carbon dioxide in teh atmosphere

11:12 AM  
Blogger maksimovich said...

They cannot!. The dendochronolgical samples are measurements of growth ,temperature, and climate. The proxies used are correlated against cosmogenic radionuclides in the ice core samples.

Cosmogenic radionuclides are produced by cosmic rays which are modulated by the Sun when propagating through the heliosphere into the atmosphere. If the produced radionuclides are stored in an appropriate archive such as ice sheets (10Be) or tree rings (14C), in principle, the time span that can be studied is only limited by about 5-10 times the respective half-life (10Be:1.5 106 y; 14C: 5730 y) and the age of the archive. However, in practice, there are several complications. The production of cosmogenic radionuclides is not only modulated by the Sun but also by the geomagnetic dipole field. In addition, after production, the cosmogenic radionuclides are subject to mixing and exchange processes before becoming stored in an archive. Therefore, without additional information on the paleomagnetic field intensity and on system effects it is difficult to draw final conclusions about the absolute levels of solar activity on millennial time scales. A potential solution to this problem is to combine 10Be records from different ice cores with the 14C record from tree rings.

There are also a number of other problems,with the sun also producing similar fractions of isotopes that can be observed during periods of high activity.

10:58 PM  
Blogger maksimovich said...

PS Astrophysicists use helium 3 and helium 4 isotopes as proxies for the solar (in)constant this is not used by climate scientists.

11:05 PM  
Blogger sagenz said...

the first bit of your answer is what I expected. The second technical part went way way over my head. But it certainly tells me you know what you are talking about. I would be interested in reading a meta post on climate change of yours. not so much about climate change directly but about how sceptical or otherwise groups of scientists are about climate change and their reasons and soundness of science for taking that position.

Unfortunately your reward will be no more than a virtual chocolate fish.

10:43 AM  
Blogger maksimovich said...

Thanks,skepticism is of course one of the structures or tenets of the scientifc complex.

One of the problems I have is the polarisation of the arguments,and some very bad science being published of course crisis sells.

I think I will cosider your offer,

M

11:05 PM  

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