Showing posts with label cosmic rays. Show all posts
Showing posts with label cosmic rays. Show all posts

Monday, September 14, 2009

Svensmark's Cosmic Clouds


I have commented on the work of Svensmark last year and this is an update of sorts. His core conjecture was that variation in the sun’s magnetic field induced a variation in the cosmic ray flux and an associated mechanism caused variation in cloud cover. As it turns out, the variation is robust enough because sun flares produce short term effects on global cloud cover as reported in this quotation:

“Giant solar flares can have the cosmic radiation on earth to dive suddenly over a few days. In the days after the eruption cloud cover falls by about 4 per cent. And the content of liquid water in clouds (droplets) is reduced by almost 7 per cent. Indeed, [you could say] that the clouds on Earth originated in space.”

So suddenly we have a robust climate change mechanism that can observed in action.

The past decade has seen the solar magnetic field slacken and the global temperature also drop slightly. I suspect that the lag time between such variations to be quite large and that suggests that the present cooling trend will last a while past any recovery in the solar magnetic field.

However, we know at least that a major magnetic change will immediately change the cosmic ray flux. And that will just as immediately adjust cloud behavior. The percentages quoted here, should they stand up to averaging over a number of events, are actually huge and represent a major multiplier of the sun’s activity and must be accounted for.

Up to now we have been trying to justify activity changes in solar radiation that was well below a percentage point with no multiplier to help. Our only past proxy for activity was the sunspot count which happens to also better reflect magnetic activity. Linking that activity to solar radiation was a red herring.

And we now know that cloud production is generated by incoming cosmic rays. My conjecture at this point is that it is the principle mechanism of cloud formation. It is just too convenient.

Svensmark: “global warming stopped and a cooling is beginning” – “enjoy global warming while it lasts”

10 09 2009

http://wattsupwiththat.com/2009/09/10/svensmark-global-warming-stopped-and-a-cooling-is-beginning-enjoy-global-warming-while-it-lasts/

This opinion piece from Professor Henrik Svensmark was published September 9th in the Danish newspaper Jyllands-Posten. Translation is from
Google translation with some post translation cleanup of jumbled words or phrases by myself. In cases were the words were badly jumbled or didn’t quite make sense I inserted [my interpretation in brackets]. Hat tip to Carsten Arnholm of Norway for bringing this to my attention. – Anthony

While the sun sleeps

HENRIK SVENSMARK, Professor, DTU, Copenhagen

Indeed, global warming stopped and a cooling is beginning. No climate model has predicted a cooling of the Earth, on the contrary. This means that projections of future climate is unpredictable, writes Henrik Svensmark.

The star which keeps us alive, has over the last few years almost no sunspots, which are the usual signs of the sun’s magnetic activity.

Last week, reported the scientific team behind Sohosatellitten (Solar and Heliospheric Observatory) that the number of sunspot-free days suggest that solar activity is heading towards its lowest level in about 100 years’. Everything indicates that the Sun is moving into a hibernation-like state, and the obvious question is whether it has any significance for us on Earth.

If you ask the International Panel on Climate Change IPCC, representing the current consensus on climate change, so the answer is a reassuring ‘nothing’. But history and recent research suggests that it is probably completely wrong. Let us take a closer look at why.

Solar activity has always varied. Around the year 1000, we had a period of very high solar activity, which coincided with the medieval warmth. It was a period when frosts in May was an almost unknown phenomenon and of great importance for a good harvest. Vikings settled in Greenland and explored the coast of North America. For example, China’s population doubled over this period. But after about 1300, the earth began to get colder and it was the beginning of the period we now call the Little Ice Age. In this cold period all the Viking settlements in Greenland disappeared. Swedes [were surprised to see Denmark to freeze over in ice], and the Thames in London froze repeatedly. But more serious was the long periods of crop failure, which resulted in a poorly nourished population, because of disease and hunger [population was reduced] by about 30 per cent in Europe.

It is important to note that the Little Ice Age was a global event. It ended in the late 19th century and was followed by an increase in solar activity. Over the past 50 years solar activity has been the highest since the medieval warmth for 1,000 years ago. And now it appears that the sun returns and is heading towards what is called ‘a grand minimum’ as we saw in the Little Ice Age.

The coincidence between solar activity and climate through the ages have tried explained away as coincidence. But it turns out that almost no matter what time studying, not just the last 1000 years, so there is a line. Solar activity has repeatedly over the past 10,000 years has fluctuated between high and low. Actually, the sun over the past 10,000 years spent in a sleep mode, approx. 17 pct of the time, with a cooling of the Earth to follow.

One can wonder that the international climate panel IPCC does not believe that the sun changed activity has no effect on the climate, but the reason is that they only include changes in solar radiation.

Just radiation would be the simplest way by which the sun could change the climate. A bit like turning up and down the brightness of a light bulb.

Satellite measurements of solar radiation has been shown that the variations are too small to cause climate change, but so has closed his eyes for a second much more powerful way the sun is able to affect Earth’s climate. In 1996 we discovered a surprising influence of the sun – its impact on Earth’s cloud cover. High energy accelerated particles of exploded stars, the cosmic radiation, are helping to form clouds.

When the Sun is active its magnetic field shields better against the cosmic rays from outer space before they reach our planet, and by regulating the Earth’s cloud cover the sun can turn up and down the temperature. High solar activity obtained fewer clouds and the earth is getting warmer. Low solar activity inferior shields against cosmic radiation, and it results in increased cloud cover and hence a cooling. As the sun’s magnetism has doubled its strength during the 20th century, this natural mechanism may be responsible for a large part of global warming during this period.

This also explains why most climate scientists are trying to ignore this possibility. It does in fact favor the idea that the 20th century temperature rise is mainly due to human emissions of CO2. If the sun as has influenced a significant part of warming in the 20 century, it means that CO2’s contribution must necessarily be smaller.

Ever since our theory was put forward in 1996, it has been through a very sharp criticism, which is normal in science.

First it was said that a link between clouds and solar activity could not be correct because no physical mechanism was known. But in 2006 after many years of work we managed to conduct experiments at DTU Space, where we demonstrated the existence of a physical mechanism. The cosmic radiation helps to form aerosols, which are the seeds for cloud formation.

Then came the criticism that the mechanism we have found in the laboratory was unable to survive in the real atmosphere and therefore had no practical significance. But the criticism we have just emphatically rejected. It turns out that the sun itself is doing, what we might call natural experiments. Giant solar flares can have the cosmic radiation on earth to dive suddenly over a few days. In the days after the eruption cloud cover falls by about 4 per cent. And the content of liquid water in clouds (droplets) is reduced by almost 7 per cent. Indeed, [you could say] that the clouds on Earth originated in space.

Therefore we have looked at the sun’s magnetic activity with increasing concern, since it began to wane in the mid-1990s.

That the sun could fall asleep in a deep minimum was suggested by [solar scientists] at a meeting in Kiruna in Sweden two years ago. As Nigel Calder and I updated our book “The Chilling Stars” therefore, we wrote a little provocative [passage] “we recommend our friends to enjoy global warming while it lasts.”

Indeed, global warming stopped and a cooling is beginning. Last week, it was argued by Mojib Latif from the University of Kiel at the UN World Climate Conference in Geneva that cooling may continue through the next 10 to 20 years.

His explanation was natural changes in North Atlantic circulation and not in solar activity. But no matter how it is interpreted, the natural variations in climate then penetrates more and more.

One consequence may be that the sun itself will show its importance for climate and thus to test the theories of global warming. No climate model has predicted a cooling of the Earth, on the contrary.

This means that projections of future climate is unpredictable. A forecast [that] says it may be warmer or colder for 50 years, is not very useful, for science is not able to predict solar activity.

So in many ways, we stand at a crossroads. The near future will be extremely interesting and I think it is important to recognize that nature is completely independent of what we humans think about it. Will Greenhouse theory survive a significant cooling of the Earth? Not in its current dominant form. Unfortunately, tomorrow’s climate challenges will be quite different than greenhouse theory’s predictions, and perhaps it becomes again popular to investigate the sun’s impact on climate.

Professor Henrik Svensmark is director of the Center for Sun-Climate Research at DTU Space. His book “The Chilling Stars” has also been published in Danish as “Climate and the Cosmos” (Gads Forlag, DK ISBN 9788712043508)

Wednesday, January 28, 2009

Global Magnetic Field

I am hesitant to say much on this until I am in possession of a lot more information. It is easy to imagine a cause and effect relationship between the waxing and waning of the magnetic field and a cosmic ray – precipitation connection. Except our real data is a mere thirty years old. During this time there was a real uptrend in apparent global heat, now recently reversed.

Magnetic fields will change at the same pace. Thus a correlation is unavoidable. And it is a compelling hypothesis.

I just think that the time spans are far too short or subject to eyeball selection that makes results suspect. We will be seeing more of this.

http://www.spacedaily.com/2006/090112183735.ojdq7esu.html

The earth's magnetic field impacts climate: Danish study COPENHAGEN, Jan 12 (AFP) Jan 12, 2009

The earth's climate has been significantly affected by the planet's
magnetic field , according to a Danish study published Monday that could challenge the notion that human emissions are responsible for global warming.

"Our results show a strong correlation between the strength of the earth's magnetic field and the amount of precipitation in the tropics," one of the two Danish geophysicists behind the study, Mads Faurschou Knudsen of the geology department at Aarhus University in western Denmark, told the Videnskab journal.

He and his colleague Peter Riisager, of the Geological Survey of Denmark and Greenland (GEUS), compared a reconstruction of the prehistoric magnetic field 5,000 years ago based on data drawn from stalagmites and stalactites found in China and Oman.

The results of the study, which has also been published in US scientific journal Geology, lend support to a controversial theory published a decade ago by Danish astrophysicist Henrik Svensmark, who claimed the climate was highly influenced by galactic cosmic ray (GCR) particles penetrating the earth's atmosphere.

Svensmark's theory, which pitted him against today's mainstream theorists who claim
carbon dioxide (CO2) is responsible for global warming, involved a link between the earth's magnetic field and climate, since that field helps regulate the number of GCR particles that reach the earth's atmosphere.

"The only way we can explain the (geomagnetic-climate) connection is through the exact same physical mechanisms that were present in Henrik Svensmark's theory," Knudsen said.

"If changes in the magnetic field, which occur independently of the earth's climate, can be linked to changes in precipitation, then it can only be explained through the magnetic field's blocking of the cosmetic rays," he said.

The two scientists acknowledged that CO2 plays an important role in the changing climate, "but the climate is an incredibly complex system, and it is unlikely we have a full overview over which factors play a part and how important each is in a given circumstance," Riisager told Videnskab.

Monday, November 3, 2008

Magnetic Portals

This is a delightful bit of science that is unexpected and it is certainly linked to the phenomena of the Northern lights.

I doubt if this is significant enough to impact on the cosmic ray flux, but we are rapidly learning that magnetic fields are much more dynamic than expected and that a feedback exists that can affect climate.

The textbooks will need a serious rewrite on this one. We now have portals between the Sun’s magnetic field and the Earth that just happens to coincide with the deepest part of winter. You could not ask for a better story for science class.


Magnetic Portals Connect Sun and Earth

Oct. 30, 2008: During the time it takes you to read this article, something will happen high overhead that until recently many scientists didn't believe in. A magnetic portal will open, linking Earth to the sun 93 million miles away. Tons of high-energy particles may flow through the opening before it closes again, around the time you reach the end of the page.

"It's called a flux transfer event or 'FTE,'" says space physicist David Sibeck of the Goddard Space Flight Center. "Ten years ago I was pretty sure they didn't exist, but now the evidence is incontrovertible."

Indeed, today Sibeck is telling an international assembly of space physicists at the 2008 Plasma Workshop in Huntsville, Alabama, that FTEs are not just common, but possibly twice as common as anyone had ever imagined.

Researchers have long known that the Earth and sun must be connected. Earth's magnetosphere (the magnetic bubble that surrounds our planet) is filled with particles from the sun that arrive via the solar wind and penetrate the planet's magnetic defenses. They enter by following magnetic field lines that can be traced from terra firma all the way back to the sun's atmosphere.

"We used to think the connection was permanent and that solar wind could trickle into the near-Earth environment anytime the wind was active," says Sibeck. "We were wrong. The connections are not steady at all. They are often brief, bursty and very dynamic."

Several speakers at the Workshop have outlined how FTEs form: On the dayside of Earth (the side closest to the sun), Earth's magnetic field presses against the sun's magnetic field. Approximately every eight minutes, the two fields briefly merge or "reconnect," forming a portal through which particles can flow. The portal takes the form of a magnetic cylinder about as wide as Earth. The European Space Agency's fleet of four Cluster spacecraft and NASA's five THEMIS probes have flown through and surrounded these cylinders, measuring their dimensions and sensing the particles that shoot through. "They're real," says Sibeck.

Now that Cluster and THEMIS have directly sampled FTEs, theorists can use those measurements to simulate FTEs in their computers and predict how they might behave. Space physicist Jimmy Raeder of the University of New Hampshire presented one such simulation at the Workshop. He told his colleagues that the cylindrical portals tend to form above Earth's equator and then roll over Earth's winter pole. In December, FTEs roll over the north pole; in July they roll over the south pole.

Sibeck believes this is happening twice as often as previously thought. "I think there are two varieties of FTEs: active and passive." Active FTEs are magnetic cylinders that allow particles to flow through rather easily; they are important conduits of energy for Earth's magnetosphere. Passive FTEs are magnetic cylinders that offer more resistance; their internal structure does not admit such an easy flow of particles and fields. (For experts: Active FTEs form at equatorial latitudes when the IMF tips south; passive FTEs form at higher latitudes when the IMF tips north.) Sibeck has calculated the properties of passive FTEs and he is encouraging his colleagues to hunt for signs of them in data from THEMIS and Cluster. "Passive FTEs may not be very important, but until we know more about them we can't be sure."

There are many unanswered questions: Why do the portals form every 8 minutes? How do magnetic fields inside the cylinder twist and coil? "We're doing some heavy thinking about this at the Workshop," says Sibeck.

Meanwhile, high above your head, a new portal is opening, connecting your planet to the sun.