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Published online 24 September 2008 | Nature 455, 441 (2008) | doi:10.1038/455441f
News in Brief
Arctic ice shrinks less this year than last
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The remarkable aspect of the 2008 minimum Arctic sea ice extent is that it came *very* close to the record loss of 2007, but it did so without the highly unusual weather conditions that contributed to last summer's historic retreat. This means that the ice cover is now so thin that any substantial recovery toward normal ice conditions is highly unlikely, especially as greenhouse gases continue to accumulate in the atmosphere. Dr. Jennifer Francis, Institute of Marine and Coastal Sciences, Rutgers University
It seems strange that the amount of Arctic ice is reported in units of area, rather than volume. Is the reversal of global warming related to NASA's report yesterday that our stormy Sun influences planet Earth in many unexpected ways, including solar wind output [See: "Ulysses Reveals Global Solar Wind Plasma Output at 50-Year Low," NASA news, 23 September 2008]? http://www.nasa.gov/home/hqnews/2008/sep/HQ_08241_Ulysses.html Oliver K. Manuel, http://myprofile.cos.com/manuelo09
Jennifer I thought the ice melt this year was meant to be larger because of the prevalence of first year ice. It looks to me as if we had a record ice-loss last year caused, as you note, by unusual weather conditions (i.e. not climate related). In 2008, there was a dramatic underlying refreeze which was somewhat offset by the first year ice effect. What does a scientist have to say about this?
In response to the question from Bishop: The recent behavior of the Arctic sea ice results from a combination of natural variations in the climate system (for example, wind patterns and ocean currents) and an increase in warming owing to increased greenhouse gases during the past several decades. The warming has gradually thinned the ice cover, leaving it vulnerable to the natural variations, which can now more easily push the ice from one place to another (which happened last year) and melt away the thin ice. If we had seen a shift in the winds this summer similar to last year, I believe the minimum extent in 2008 would have been lower than last year. We cannot yet predict with sufficient accuracy these weather patterns, but we can say with certainty that as the warming continues and the ice remains thin, any natural anomalies that occur will have a large impact on the Arctic ice cover. Jennifer Francis, PhD, Rutgers University
Jennifer Francis may be right in stating that "The warming has gradually thinned the ice cover," and " we can say with certainty that as the warming continues and the ice remains thin, any natural anomalies that occur will have a large impact on the Arctic ice cover." Would she please tell us (1.) If and how the thickness of the ice is measured? [As I said before, it seems strange that "the amount of Arctic ice is reported in units of area, rather than volume."], and (2.) If she thinks Earth's climate is immune to changes in the Sun's outflow of material in the solar wind [See: "Ulysses Reveals Global Solar Wind Plasma Output at 50-Year Low," NASA news, 23 September 2008]? http://www.nasa.gov/home/hqnews/2008/sep/HQ_08241_Ulysses.html Thanks, Oliver K. Manuel, http://myprofile.cos.com/manuelo09
Response to questions from O. Manuel: 1) Most studies of sea ice change refer to the areal coverage of ice rather than volume because satellites, ships, and aircraft can more readily detect whether or not ice exists in a particular location. Ice thickness (needed to assess volume) is much harder to determine, as most remote-sensing instruments cannot penetrate the ice. Estimates of volume change have been made using satellite measurments of ice freeboard (how high it floats on the ocean surface), ice depth below the surface by underwater buoys and submarines, and computer models. All of these estimates suggest that ice volume has also decreased substantially in recent decades. More information and data are available at the National Snow and Ice Data Center (nsidc.org). 2) Changes in the sun have certainly played a role in climate change over long time periods, but many recent studies discount solar activity as a contributor to the rapid changes observed in recent decades. This article from BBC News summarizes these findings from the world's experts in this field of research: http://news.bbc.co.uk/2/hi/uk_news/6290228.stm.
Jennifer, thank you for the link to the BBC News article finding that the sun's effects on climate today are minimal. Many of us would like greater closure than there now appears to be on the issue of the relative strengths of the different forces causing present day warming. It will certainly be easier for governments to begin to seriously deal with emissions of GHGs if influential parts of the electorate no longer strongly oppose the notion that these gases are responsible for the great majority of the warming we now see. As noted in comments above, NASA has now said that the sun is in a very quiescent stage. There have been virtually no sunspots for about 80 days now, and some questioners suggest that the sun's activity will be similar to that of the Dalton minimum around 1810-1815. Thus we may be at a stage to empirically test the notion that the sun is considerably more influential than thought by the IPCC. It seems to me -- not a climate scientist -- that if sea levels continue to rise, glaciers continue to retreat, temperatures are little affected, then the empirical test will likely have demonstrated that solar influences today really are minimal in relation to GHG influences. If sea levels fall, glaciers grow, and temperatures fall, then perhaps the sun's influence may have been understated. Do you think this is a fair statement, or have I missed a subtlety? I don't include melting Arctic sea ice as part of this test, by the way, because of the apparent large influence of Asian black carbon emissions (separate from CO2 influences) on such melting (from Ramanathan's April 2008 paper in Nature Geoscience, "Global and regional climate changes due to black carbon").
Response to question from Tom Grahame: The experiment you describe has been underway since 2000, when solar output and sunspot numbers began a steady decline (see graph of data from NASA at http://sdo.gsfc.nasa.gov/images/site/sunspot_tsi_web.png). During this period, however, global temperatures have continued to increase -- in fact, the eight warmest years on record occurred since 1998 (see http://www.giss.nasa.gov/research/news/20080116/). Sea levels are also continuing to rise (which is expected, as there is a long lag in their response to forcing) and glaciers continue to shrink. In addition, the surface area of Greenland that undergoes melt each summer has continued to grow, and spring snow-cover in the N. Hemisphere has declined. To me the conclusion from this experiment is already clear.
Response to Jennifer Francis: I have no doubt that you personally believe what you write, but frankly many of your opinions are factually incorrect. Compare your 27 Sept 2008 claim that, "the EIGHT WARMEST YEARS on record occurred since 1998" with _1.) A report from Dr. Syun Akasofu of the International Arctic Research Center in the 29 Sept 2008 issue of CCNet: "Recent studies of the global temperature changes by the University of East Anglia (UK), the Hadley Climate Research Center (UK), NOAA, the Japan Meteorological Agency, and the University of Alabama Huntsville show that the global warming trend stopped in about 2000-2001. This is contrary to the prediction of the IPCC. They claim that the global average temperature will continue to increase so long as the amount of CO2 in the atmosphere keeps increasing." [The Recovery from the Little Ice Age and The Recent Halting of the Warming, 25 September 2008] http://people.iarc.uaf.edu/~sakasofu/little_ice_age.php , and _2.) The abstract of Lord Christopher Monckton's new paper: "An extraordinary series of postings at www.climateaudit.org, the deservedly well trafficked website of the courageous and tenacious Canadian statistician Steve McIntyre, is a remarkable indictment of the corruption and cynicism that is rife among the alarmist climate scientists favored by the UN's discredited climate panel, the IPCC. In laymen's language, the present paper respectfully summarizes Dr. McIntyre's account of the systematically dishonest manner in which the "hockey-stick" graph falsely showing that today's temperatures are warmer than those that prevailed during the medieval climate optimum was fabricated in 1998/9, adopted as the poster-child of climate panic by the IPCC in its 2001 climate assessment, and then retained in its 2007 assessment report despite having been demolished in the scientific literature. It is a long tale, but well worth following. No one who reads it will ever again trust the IPCC or the "scientists" and environmental extremists who author its climate assessments." [Hockey Stick? What Hockey Stick? 12 September 2008] http://scienceandpublicpolicy.org/monckton/what_hockey_stick.html Lord Mocton concludes: "The need to look to the State for nearly all science funding has inflicted upon the scientific community a dull, dishonest uniformity, so that the deliberate falsification of results to support the current official orthodoxy has become commonplace, particularly where the climate question is concerned." Regretfully I have personally observed the same intellectual dishonesty in solar, space, particle and astro-physics. The object that heats planet Earth bears little or no resemblence to the fairy tale model of an Hydrogen-filled star described by the standard solar model. [The Sun is a plasma diffuser that sorts atoms by mass, Phys. Atom. Nucl. 69 (2006) 1847-1856, http://arxiv.org/pdf/astro-ph/0609509v3] Oliver K. Manuel, http://myprofile.cos.com/manuelo09
Response to comments by O. Manuel: If one glances at the graphs of global temperature records from NASA or the sites Dr. Manuel lists, one sees a flattening of the warming trend since 2000. It is easy to surmise that global warming has stopped. However, if one reads the discussion accompanying these graphs (the Universty of East Anglia's site is a good resource: http://www.cru.uea.ac.uk then click on "Climate Change Myths"), one learns that this leveling of global temperatures is well understood, and due to a recent tendency for La Nina conditions, which cools the tropical Pacific and has the effect of masking greenhouse-gas-induced warming. In 1998, the warmest year on record, the situation was reversed: El Nino conditions (warmer Pacific waters) augmented the warming trend. Regarding Dr. Manual's comments on the so-called hockey-stick temperature reconstruction, I direct the reader toward an excellent discussion based on *peer-reviewed* quantitative papers published in highly respected scientific journals: "Myth vs. Fact Regarding the 'Hockey Stick'" on www.realclimate.org. My beliefs and opinions are founded in fact and scientific research by experts in their field, not the writings of a British politician.
Jennifer does not repeat her earlier claim that "the EIGHT WARMEST YEARS on record occurred since 1998". In fact she now says "one one sees a flattening of the warming trend since 2000." Why? Has the level of CO2 in air flatten since 2000? Has the number of sunspots decreased since 2000? Has the solar wind faded since 2000? http://www.nasa.gov/home/hqnews/2008/sep/HQ_08241_Ulysses.html I urge Jennifer to spend a little time studying quantitative data on the object that heats planet Earth [The Sun is a plasma diffuser that sorts atoms by mass, Phys. Atom. Nucl. 69 (2006) 1847-1856, http://arxiv.org/pdf/astro-ph/0609509v3]. Then she might understand why the title of this news report could be changed to "Arctic ice increases since last year". Oliver K. Manuel, http://myprofile.cos.com/manuelo09
Response to comment by Oliver: Jennifer is correct. Both statements by Jennifer - "a flattening of the warming trend since 2000" and "the eight warmest years on record have occurred since 1998" can be and are true. Syun Akasofu's claim that warming stopped in 2000-2001 is also true in a very naive sense. However, an 6-7 year period does not constitute a significant climate trend. It is merely reflective of short-term variations in climate due to, as Jennifer mentions, El Nino and La Nina variability, as well as other natural variations in climate. The key thing is to not confuse short-term (a few years) variations in climate - which can be natural - to the long-term trends - which have clearly been linked to human GHG emissions. In regards to your earlier question on sea ice volume that Jennifer answered, I would add that while we can't put hard numbers on the exact volumes, all indications are that we likely ended the 2008 melt season with the lowest volume of Arctic sea ice in the satellite record (since 1979). See: http://nsidc.org/news/press/20081002_seaice_pressrelease.html for more info. I'll also mention a just-published paper in Geophysical Research Letters by England et al., that indicates the recent changes in Arctic sea ice are unprecedented in at least 5500 years. Walt Meier Research Scientist National Snow and Ice Data Center
Walt: The case that you and Jennifer are trying to make for Anthropological Global Warming (AGW) is not advanced by yet another set of inconsistent, unscientific, and inaccurate statements: "while we can't put hard numbers on the exact volumes" . . . "we likely ended the 2008 melt season with the lowest volume of Arctic sea ice in the satellite record (since 1979)." Oliver K. Manuel, http://myprofile.cos.com/manuelo09
Putting aside wishful thinking, these are the factual headlines for new experimental observations related to global climate change: 1. SUN-SPOTS VANISH [ http://wattsupwiththat.com/2008/09/30/nasa-sun-is-blankety-blankest-its-been-in-the-space-age/ ]; 2. SOLAR WIND FADES [ http://www.nasa.gov/home/hqnews/2008/sep/HQ_08241_Ulysses.html ]; 3. GLOBAL TEMPERATURES PLUNGE [ http://wattsupwiththat.com/2008/02/19/january-2008-4-sources-say-globally-cooler-in-the-past-12-months/ ]; and 4. ARTIC ICE INCREASES [ http://www.nature.com/news/2008/080924/full/455441f.html ] Oliver K. Manuel, http://www.omatumr.com/index.html, http://myprofile.cos.com/manuelo09
Oliver: The volume was either the lowest or second lowest. To the best we can estimate at the moment using near-real-time data, it appears to be the lowest, but there is still uncertainty in the data. Regardless, both sea ice extent and volume are on a significant long-term downward trend. Any good science recognizes uncertainty and makes definitive conclusions only on what the uncertainty allows. That is why scientists can say the case for AGW is made. Any uncertainty is small relative to that conclusion. The points you make on the sun have very little to do with AGW. Solar variation cannot explain the temperature trends over the past 30 years.
Walt: Long term, there has been gradual global warming since the end of the last Little Ice Age. That warming was NOT caused by the release of man-made CO2. Artic ice cover changes each year with the season, as shown here for 2002, 2003, 2004, 2005, 2006, 2007 and 2008 to present. http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm With kind regards, Oliver K. Manuel, http://myprofile.cos.com/manuelo09