Sun's Activity Increased in Past Century, Study Confirms

Space.com ^ | 9/26/06 | By Jeanna Bryner

[Straight Vermonter]

The energy output from the Sun has increased significantly during the 20th century, according to a new study.

Many studies have attempted to determine whether there is an upward trend in the average magnitude of sunspots and solar flares over time, but few firm conclusions have been reached.

Now, an international team of researchers led by Ilya Usoskin of the Sodankylä Geophysical Observatory at the University of Oulu, Finland, may have the answer. They examined meteorites that had fallen to Earth over the past 240 years. By analyzing the amount of titanium 44, a radioactive isotope, the team found a significant increase in the Sun's radioactive output during the 20th century.

Over the past few decades, however, they found the solar activity has stabilized at this higher-than-historic level.

Prior research relied on measurements of certain radioactive elements within tree rings and in the ice sheets covering Greenland and Antarctica, which can be altered by terrestrial processes, not just by solar activity. The isotope measured in the new study is not affected by conditions on Earth.

The results, detailed in this week's issue of the journal Astronomy & Astrophysics Letters, "confirm that there was indeed an increase in solar activity over the last 100 years or so," Usoskin told SPACE.com.

The average global temperature at Earth's surface has risen by about 1 degree Fahrenheit since 1880. Some scientists debate whether the increase is part of a natural climate cycle or the result of greenhouse gases produced by cars and industrial processes.

The Sun's impact on climate has only recently been investigated. Recent studies show that an increase in solar output can cause short-term changes in Earth's climate, but there is no firm evidence linking solar activity with long-term climate effects.

The rise in solar activity at the beginning of the last century through the 1950s or so matches with the increase in global temperatures, Usoskin said. But the link doesn't hold up from about the 1970s to present.

"During the last few decades, the solar activity is not increasing. It has stabilized at a high level, but the Earth's climate still shows a tendency toward increasing temperatures," Usoskin explained.

He suspects even if there were a link between the Sun's activity and global climate, other factors must have dominated during the last few decades, including the increase of greenhouse gases in the atmosphere.

[Straight Vermonter]

"During the last few decades, the solar activity is not increasing. It has stabilized at a high level, but the Earth's climate still shows a tendency toward increasing temperatures," Usoskin explained.

I think this follows the same trends we see here in annual weather patterns. By July/August daylight hours are already getting shorter, meaning less solar activity, yet the temps are still increasing. In the winter we see the same trend with daylight increasing in January/February and yet temps continue to fall.

[Straight Vermonter]

Ping

[proud_yank]

What's Al Gore's explanation for this, SUV's and industrial capitalism on the sun?

[Plutarch]

IBTB'sF

[wafflehouse]

Recent studies show that an increase in solar output can cause short-term changes in Earth's climate, but there is no firm evidence linking solar activity with long-term climate effects.

paging Captain Obvious...

[DaveTesla]

Todays Forecast:
Hot and sunny with cooling in the near future.

Long Range Solar Forecast

05.10.2006

Solar Cycle 25 peaking around 2022 could be one of the weakest in centuries. May 10, 2006: The Sun's Great Conveyor Belt has slowed to a record-low crawl, according to research by NASA solar physicist David Hathaway. "It's off the bottom of the charts," he says. "This has important repercussions for future solar activity." The Great Conveyor Belt is a massive circulating current of fire (hot plasma) within the Sun. It has two branches, north and south, each taking about 40 years to perform one complete circuit. Researchers believe the turning of the belt controls the sunspot cycle, and that's why the slowdown is important. Right: The sun's "Great Conveyor Belt" in profile. "Normally, the conveyor belt moves about 1 meter per second—walking pace," says Hathaway. "That's how it has been since the late 19th century." In recent years, however, the belt has decelerated to 0.75 m/s in the north and 0.35 m/s in the south. "We've never seen speeds so low." According to theory and observation, the speed of the belt foretells the intensity of sunspot activity ~20 years in the future. A slow belt means lower solar activity; a fast belt means stronger activity. The reasons for this are explained in the Science@NASA story Solar Storm Warning. "The slowdown we see now means that Solar Cycle 25, peaking around the year 2022, could be one of the weakest in centuries," says Hathaway. This is interesting news for astronauts. Solar Cycle 25 is when the Vision for Space Exploration should be in full flower, with men and women back on the Moon preparing to go to Mars. A weak solar cycle means they won't have to worry so much about solar flares and radiation storms. Above: In red, David Hathaway's predictions for the next two solar cycles and, in pink, Mausumi Dikpati's prediction for cycle 24. On the other hand, they will have to worry more about cosmic rays. Cosmic rays are high-energy particles from deep space; they penetrate metal, plastic, flesh and bone. Astronauts exposed to cosmic rays develop an increased risk of cancer, cataracts and other maladies. Ironically, solar explosions, which produce their own deadly radiation, sweep away the even deadlier cosmic rays. As flares subside, cosmic rays intensify—yin, yang. Hathaway's prediction should not be confused with another recent forecast: A team led by physicist Mausumi Dikpata of NCAR has predicted that Cycle 24, peaking in 2011 or 2012, will be intense. Hathaway agrees: "Cycle 24 will be strong. Cycle 25 will be weak. Both of these predictions are based on the observed behavior of the conveyor belt." How do you observe a belt that plunges 200,000 km below the surface of the sun? "We do it using sunspots," Hathaway explains. Sunspots are magnetic knots that bubble up from the base of the conveyor belt, eventually popping through the surface of the sun. Astronomers have long known that sunspots have a tendency to drift—from mid solar latitudes toward the sun's equator. According to current thinking, this drift is caused by the motion of the conveyor belt. "By measuring the drift of sunspot groups," says Hathaway, "we indirectly measure the speed of the belt." Right: Hathaway monitors the speed of the Conveyor Belt by plotting the drift of sunspot groups from high to low solar latitude. This plot is called "the Butterfly Diagram." The tilt of the wings reveal the speed of the Conveyor Belt. [More] Using historical sunspot records, Hathaway has succeeded in clocking the conveyor belt as far back as 1890. The numbers are compelling: For more than a century, "the speed of the belt has been a good predictor of future solar activity." If the trend holds, Solar Cycle 25 in 2022 could be, like the belt itself, "off the bottom of the charts."

[Retief]

Think of it as thermal inertia.

[Cap Huff]

"The Sun's impact on climate has only recently been investigated."

BWAAHAAHAAHAAAHAAHAA!!!!

[Straight Vermonter]

You said it better in 2 words than I did in 2 sentences!

[Dallas59]

Bush better stop messin with the Sun!

[DeaconRed]

How in the Sam Hell did "W" get up there?

[DaveTesla]

[Prospero]

this follows the same trends we see here in annual weather patterns. By July/August daylight hours are already getting shorter, meaning less solar activity, yet the temps are still increasing. In the winter we see the same trend with daylight increasing in January/February and yet temps continue to fall.

This has always been the case, the temperature increase after the Summer Solstice, "the longest day," which used to be more tellingly known as "Midsummers Day," because of a lag of temperature change in the weeks after the peak day of "insolation." Also, even though the period of daylight begins to decrease greatly after the Summer Solstice, weeks of high, full daylight at the North Pole for example, where a full sun (even at an increasingly oblique angle) continues until the Equinox (last week) Just an observation.

[Drammach]

The average global temperature at Earth's surface has risen by about 1 degree Fahrenheit since 1880.

Coinciding with the approximate end of the Little Ice Age...

Just guessing, but I would expect that further investigation will eventually show a decrease in solar activity / radiation during the period of the Little Ice Age..

[FreedomCalls]

That's a good one.

[Larry Lucido]

It's worst than we thought. Global warming is now causing solar warming, too!

[maryz]

In "Actual Method," don't you mean "Modify data to fit theory"? ;-)

Seems to happen a lot anyway!

[shteebo]

What's Al Gore's explanation for this, SUV's and industrial capitalism on the sun?

Isn't it obvious? Greenhouse gases are heating up the earth and the earth, in turn, is heating the sun. My God, our SUVs are smoking the whole solar system. We better elect some Democrats to stop this craziness.

[backhoe]

When you google "mass of the solar system," you learn:

The Sun is by far the largest object in the solar system. It contains more than 98.8% of the total mass of the Solar System (Jupiter contains most of the rest).

So my guess is Sol is the master controller, and the works of Man probably doesn't have much effect... here's a picture:

-- here's another for perspective:

A picture's worth a thousand words...

An early- and still favorite- post of mine:

The Sun has a Thousand Faces--- Thread
3

[Dan Evans]

Do those two minimums on your solar chart at 1671 and 1811 correspond to climate events?