Just a few articles for your attention. Geoscience and climate science may be among the most powerful forces shaping the early 21st century. They deserve close attention, IMO — however unfamilar to those accustomed to (incorrectly) thinking of economic, political, and military forces as the major drivers of history.
- “Danger ahead as the Sun goes quiet“, New Scientist, 7 January 2009 — This is a description for a general audience of the following article.
- “For how long will the current grand maximum of solar activity persist?“, J. A. Abreu, J. Beer, F. Steinhilber, S. M. Tobias, N. O. Weiss, Geophysical Research Letters, 30 October 2008
(3) The big news is a revision of solar cycle 24 forecasts by Dr. Hathaway of NASA. (summary by Michael Ronayne, posted at the SolarCycle24 message board. The significance: increased odds of cooler weather during this 11 year solar cycle (think crop failures, possible famine).
On January 5, 2009 Dr. David Hathaway has again made revisions to his predictions for Solar Cycle 24. The new predictions for December 2008 were incorrectly identified as January 2008; I suspect that this error will be corrected shortly. Here is a summary of the changes which were made.
- SC24 maximum was pushed back another 6 months to November 2012.
- The mean Sunspot Number at solar maximum was reduced by 30 points to 105.
- SC24 was extended to 2020.
- The background Sun image was changed and is now less cluttered.
Dr. Hathaway’s latest predictions are starting to look a lot like the predictions which Dr. Leif Svalgaard made several years ago. Here is an animation of Dr. Hathaway’s predictions. Remember these tips to view the animation in IE:
- To toggle the full screen between full and normal screen press the F11 function key.
- If your graphic image is too small, use the magnifying glass pointer to expand it.
- To stop the animation press the ESC key.
- To restart the animation press the F5 function key.
For more information about Dr. Hathaway’s forecasts.
(1) “Danger ahead as the Sun goes quiet“, New Scientist, 7 January 2009 — This is a description for a general audience of the follow article.
THE sun’s ability to shield the solar system from harmful cosmic rays could falter in the early 2020s, just in time to threaten the health of NASA astronauts as they return to the moon.
As well as the 11-year cycle of sunspots and solar flares, the sun’s activity experiences longer-term shifts lasting several decades. The sun is currently in a long-term high, having been relatively active for nearly a century, but it is not known when this will end.
To find out, a team led by Jose Abreu of the Swiss Federal Institute of Aquatic Science and Technology in Duebendorf analysed 66 long-term highs from the past 10,000 years, as recorded in fluctuating levels of rare isotopes such as beryllium-10 in ice cores from Greenland. These are produced when cosmic rays break down the nuclei of oxygen and nitrogen atoms in the Earth’s atmosphere. Production of these isotopes peaks when the sun is inactive, as the weaker solar wind lets more cosmic rays enter the solar system, which hit the Earth.
Based on the duration of past highs, and the fact that the current one has already lasted 80 years, the team has calculated that its most likely total lifetime is between 95 and 116 years, and they suspect the high will probably end at the shorter end of this range.
(2) “For how long will the current grand maximum of solar activity persist?“, J. A. Abreu, J. Beer, F. Steinhilber, S. M. Tobias, N. O. Weiss, Geophysical Research Letters, 30 October 2008 — Abstract:
Understanding the Sun’s magnetic activity is important because of its impact on the Earth’s environment. The sunspot record since 1610 shows irregular 11-year cycles of activity; they are modulated on longer timescales and were interrupted by the Maunder minimum in the 17th century. Future behavior cannot easily be predicted – even in the short-term.
Recent activity has been abnormally high for at least 8 cycles: is this grand maximum likely to terminate soon or even to be followed by another (Maunder-like) grand minimum? To answer these questions we use, as a measure of the Sun’s open magnetic field, a composite record of the solar modulation function Φ, reconstructed principally from the proxy record of cosmogenic 10Be abundances in the GRIP icecore from Greenland. This Φ record extends back for almost 10,000 years, showing many grand maxima and grand minima (defined as intervals when Φ is within the top or bottom 20% of a Gaussian distribution).
We carry out a statistical analysis of this record and calculate the life expectancy of the current grand maximum. We find that it is only expected to last for a further 15-36 years, with the more reliable methods yielding shorter expectancies, and we therefore predict a decline in solar activity within the next two or three cycles. We are not able, however, to predict the level of the ensuing minimum.
If you are new to this site, please glance at the archives below. You may find answers to your questions in these.
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For more information from the FM site
To read other articles about these things, see the FM reference page on the right side menu bar. Of esp relevance to this topic:
- Posts about Science, Nature, and Geopolitics– this lists not only posts on the FM site, but also a wide range of other online sources.
A few of the posts on the FM site about climate change:
- Worrying about the Sun and climate change: cycle 24 is late, 10 July 2008
- Update: is Solar Cycle 24 late (a cooling cycle, with famines, etc)?, 15 july 2008
- Solar Cycle 24 is still late, perhaps signalling cool weather ahead, 2 September 2008
- Update on solar cycle 24 – and a possible period of global cooling, 1 October 2008
- This week’s report on the news in climate science, 7 December 2008
- An important new article about climate change, 29 December 2008
- My “wish list” for the climate sciences in 2009, 2 January 2009
- About the recent conference ”Solar Activity during the onset of Solar Cycle 24″, 3 January 2009