Update on solar cycle 24 – and a possible period of global cooling

Summary:  Data continues to accumulate that something unusual — or at least different from recent history — is happening in the Sun.  This might lead to a period of cooling on Earth.

1. “Solar Wind Loses Power, Hits 50-year Low“, NASA, 23 September 2008
2. “Spotless Sun: Blankest Year of the Space Age“, NASA, 30 September 2008
3. Possible significance of this for earth’s climate

A hat tip on these stories to Watts Up with That — “Commentary on puzzling things in life, nature, science, technology, and recent news by Anthony Watts.”

Contents and Excerpts

1.  “Solar Wind Loses Power, Hits 50-year Low“, NASA, 23 September 2008 — Excerpt:

In a briefing today at NASA headquarters, solar physicists announced that the solar wind is losing power.  “The average pressure of the solar wind has dropped more than 20% since the mid-1990s,” says Dave McComas of the Southwest Research Institute in San Antonio, Texas. “This is the weakest it’s been since we began monitoring solar wind almost 50 years ago.”

McComas is principal investigator for the SWOOPS solar wind sensor onboard the Ulysses spacecraft, which measured the decrease. Ulysses, launched in 1990, circles the sun in a unique orbit that carries it over both the sun’s poles and equator, giving Ulysses a global view of solar wind activity.

… “What we’re seeing is a long term trend, a steady decrease in pressure that began sometime in the mid-1990s,” explains Arik Posner, NASA’s Ulysses Program Scientist in Washington DC.

How unusual is this event?  “It’s hard to say. We’ve only been monitoring solar wind since the early years of the Space Age-from the early 60s to the present,” says Posner. “Over that period of time, it’s unique. How the event stands out over centuries or millennia, however, is anybody’s guess. We don’t have data going back that far.”

… “The solar wind isn’t inflating the heliosphere as much as it used to,” says McComas. “That means less shielding against cosmic rays.”

In addition to weakened solar wind, “Ulysses also finds that the sun’s underlying magnetic field has weakened by more than 30% since the mid-1990s,” says Posner. “This reduces natural shielding even more.”

Unpublished Ulysses cosmic ray data show that, indeed, high energy (GeV) electrons, a minor but telltale component of cosmic rays around Earth, have jumped in number by about 20%.  These extra particles pose no threat to people on Earth’s surface. Our thick atmosphere and planetary magnetic field provide additional layers of protection that keep us safe.

2.  “Spotless Sun: Blankest Year of the Space Age“, NASA, 30 September 2008 — Excerpt:

Astronomers who count sunspots have announced that 2008 is now the “blankest year” of the Space Age.

As of Sept. 27, 2008, the sun had been blank, i.e., had no visible sunspots, on 200 days of the year. To find a year with more blank suns, you have to go back to 1954, three years before the launch of Sputnik, when the sun was blank 241 times.

“Sunspot counts are at a 50-year low,” says solar physicist David Hathaway of the NASA Marshall Space Flight Center. “We’re experiencing a deep minimum of the solar cycle.”

… If solar activity continues as low as it has been, 2008 could rack up a whopping 290 spotless days by the end of December, making it a century-level year in terms of spotlessness.

Hathaway cautions that this development may sound more exciting than it actually is: “While the solar minimum of 2008 is shaping up to be the deepest of the Space Age, it is still unremarkable compared to the long and deep solar minima of the late 19th and early 20th centuries.” Those earlier minima routinely racked up 200 to 300 spotless days per year.

3.  Possible significance of this for earth’s climate

The effect of solar activity on Earth’s climate is hotly debated, an insurgent theory vs. the dominant paradigm in climate science.  At the center of the cu rent debate are Henrik Svensmark and Nigel Calder, authors of The Chilling Stars: A New Theory of Climate Change.  They believe that cosmic rays have more effect on the climate than manmade CO2. 

An explanation of this theory by John-x in a comment posted at Watts Up with That?

It’s called ISCCP – International Satellite Cloud Climatology Project – a long-term record of satellite-based observations of cloud cover.  Svensmark used it to show good correlation between increased GCR (galactic cosmic radiation) and low cloud cover.   {see this page for more about cosmic rays}

GCRis more abundant during solar minimum (like now).  The theory is that very high-energy neutrons which were blasted out of exploding stars elsewhere in the galaxy hit the atmosphere, and produce a cascade of smaller energetic particles, some of which end up ionizing (producing an electric charge) in the lower atmosphere.  The electric charge increases the formation of aerosols, including sulphuric acid, which both provide nuclei on which water droplets can condense, and attract dust, sea salt, pollen, etc, to provide more and larger condensation nuclei.

The effect of ionization by GCR in this theory is to preferentially produce low clouds.  It is known that low clouds, by themselves, produce net cooling at the surface, whereas high clouds, by themselves, produce net warming.

So a process which preferentially produces low clouds would also preferentially produce cooler temperatures.

For more on this see Wikipedia and Svensmark’s page at the National Space Institute of the Technical University of Denmark.

Afterword

If you are new to this site, please glance at the archives below.  You may find answers to your questions in these.

Please share your comments by posting below.  Please make them brief (250 words max), civil, and relevant to this post.  Or email me at fabmaximus at hotmail dot com (note the spam-protected spelling). 

Other sources of information about the Solar Cycle

(a)  For current data and analysis

1. Daily sun watch at Spaceweather.com
2. NOAA’s  Space Weather Prediction Center (SWPC), including their Solar Cycle Progression page and the latest predictions.
3. NASA’s background information about Solar Cycle Predictions
4. Detailed information at SolarCycle24.com
5. Solaemon’s Spotless Days Page — Excellent graphs of historical sunspot activity

(b)  Other posts on this site

1. Worrying about the Sun and climate change: cycle 24 is late, 10 July 2008
2. Update: is Solar Cycle 24 late (a cooling cycle, with famines, etc)?, 15 July 2008
3. Solar Cycle 24 is still late, perhaps signalling cool weather ahead, 2 September 2008

For more information about global warming

(a)  Other posts on this site

1. A look at the science and politics of global warming, 12 June 2008
2. Global warming means more earthquakes!, 19 June 2008
3. An article giving strong evidence of global warming, 30 June 2008
4. More forecasts of a global cooling cycle, 15 July 2008
5. Two valuable perspectives on global warming, 4 August 2008
6. President Kennedy speaks to us about global warming and Climate Science, 7 August 2008 

(b)  Information from other sources

1. “SURFACE TEMPERATURE RECONSTRUCTIONS FOR THE LAST 2,000 YEARS“, Board on Atmospheric Sciences and Climate, Division on Earth and Life Studies, NATIONAL RESEARCH COUNCIL OF THE NATIONAL ACADEMIES (2006) — aka The North Report.
2. Report of the “Ad Hoc Committee on the Hockey Stick Global Climate Reconstruction”, commissioned by the House Committee on Energy and Commerce (July 2006) — aka The Wegman Report.  Also note this excerpt from the Q&A session of the Dr. Edward J. Wegman’s testimony.
3. “The role of statisticians in public policy debates over climate change“, Richard L. Smith, American Statistical Association – Section on Statistics & the Environment Newsletter (Spring 2007) — One of the too-few reports by statisticians on the climate change literature.
4. A timeline of the science and politics of climate science.
5. A Bibliography by year of climate science research.