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Health & Fitness

Man-Made Global Warming: Settled Science?

We've taken the watch apart, but we still don't know how it works.

INTRODUCTION:

I started writing this almost as soon as I accepted Brian Crawford's challenge in another post: list five peer-reviewed studies, published in scientific journals, which deny that Mankind is ultimately responsible for global warming ("anthropogenic global warming," or "AGW"), and enjoy lunch at his treat.

Editor's note: The challenge from Brian Crawford came in a comment he posted on the blog "Fall Officially Begins This Saturday." 

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I love my food: how could I possibly resist?

But within 2 hours, I had 2,000+ such papers to choose from, and in 24 hours my "editorial" had become a 20+ page "review of the literature." Since I’m only looking for lunch (not groceries for life), I limited my list to 5 points which question key aspects of the AGW paradigm, with 4 journal-published, peer-reviewed studies for each point: 1 for each dollar of Mr. Crawford’s potential tab.

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As a result, this list is tiny. Anyone interested can use this as a starting point, and go from there. Also, none of the many papers which support AGW theories are found here, but I think that side of the story is already well-publicized.

No doubt, some will either denigrate or applaud this effort. Some will use politics, some will use science; some will quote “the experts,” and some will just need to say something. Do not expect my response to any of it, but all of it is fine with me.

You see, I treasure the freedom of speech, because it means the freedom of competing ideas. Good ideas are honed and refined by questioning, thrive on open discussion. Bad ideas require the silencing of the debate, or they get revealed for what they are: bad. So when someone, however “expert,” however high-ranking or respected, tells me “the debate is over, sit down and shut-up….” Well, I want to know "why?" And they'd better have a good reason.

The UN's Intergovernmental Panel on Climate Change (IPCC) might be generally right about the AGW issue. The Non-governmental International Panel on Climate Change’s (NIPCC) conclusions might be little beyond hot air. But the science, as such, is nowhere close to being "decided," no matter what Al Gore or Rush Limbaugh have to say, and I don't appreciate the self-appointed disciples of either side trying to shut off the debate when it's only just begun.

A BIT OF THE SCIENCE:

1) HASN'T THE 20th CENTURY BEEN UNUSUALLY HOT, OR SEEN AN UNUSUAL RATE OF WARMING? - The Current Warming Period is neither unusual, nor remarkable, nor unprecedented in recent human history. 

a) Weichao Wu, Wenbing Tan, Liping Zhou, Huan Yang, Yunping Xu: Sea surface temperature variability in southern Okinawa Trough during last 2700 years. Geophysical Research Letters, (2012) currently in press. DOI:10.1029/2012GL052749  (*My illustration is from this source.)

b) Joan Bunbury, Konrad Gajewski: Temperatures of the past 2000 years inferred from lake sediments, southwest Yukon Territory, Canada. Quaternary Research, (03 May 2012) Volume 77, Issue 3, pp.355-367.  http://dx.doi.org/10.1016/j.ygres.2012.01.002

c) Michael-Shawn Fletcher, Patricio Iván Moreno: Vegetation, climate and fire regime changes in the Andean region of southern Chile (38°S) covaried with centennial-scale climate anomalies in the tropical Pacific over the last 1500 years Quaternary Science Reviews, (16 July 2012) Volume 4, Pages 46–56.  http://dx.doi.org/10.1016/j.quascirev.2012.04.016

d) Scott Mensing, John Korfmacher, Thomas Minckley, Robert Musselman: A 15,000 year record of vegetation and climate change from a treeline lake in the Rocky Mountains, Wyoming, USA, The Holocene, (July 2012) vol. 22 no. 7 p.739-748. Available online prior to publishing December 2011. DOI:10.1177/0959683611430339

2) AREN’T WE PUTTING MORE CO2 IN THE ATMOSPHERE THAN EVER? – Mankind’s emissions of CO2 are at an all-time high. In spite of this, current atmospheric CO2 levels (<400ppm) are closer to record lows (~200ppm) than record highs (>4,000ppm), and the current rate of CO2 rise is not unusual in the natural record.

a) Daniel H. Rothman: Atmospheric carbon dioxide levels for the last 500 million years, PNAS [Proceedings of the National Academy of Sciences of the USA], (02 April 2002) vol. 99 no. 7 pp.4167-4171.  Published online before print 19 March 2002.  DOI:10.1073/pnas.022055499

b) Friederike Wagner, Sjoerd J. P. Bohncke, David L. Dilcher, Wolfram M. Kürschner, Bas van Geel, Henk Visscher: Century-scale shifts in early Holocene atmospheric CO2 concentration, Science, (18 June 1999) Vol. 284 no. 5422 pp.1971-1973. DOI:10.1126/science.284.5422.1971

c) Gregory J. Retallack: A 300-million-year record of atmospheric carbon dioxide from fossil plant cuticles, Nature, (17 May 2001) vol.411, pp.287-290. DOI:10.1038/35077041

d) Michael D. Dettinger, Michael Ghil: Seasonal and interannual variations of atmospheric CO2 and climate, Tellus Series B: Chemical and Physical Meteorology [International Meteorological Institute, Stockholm], (February 1998) Volume 50, Issue 1, pages 1–24. DOI:10.1034/j.1600-0889.1998.00001.x

3) DON'T GREENHOUSE GASSES LIKE CO2 DRIVE TEMPERATURE CHANGE? – Despite CO2's known greenhouse properties, changes in atmospheric CO2 lag behind changes in temperature on all observed time-scales.

a) Ole Humlum, Kjell Stordahl, Jan-Erik Solheim: The phase relation between atmospheric carbon dioxide and global temperature, Global and Planetary Change, (2012). Available online 30 August 2012.  http://dx.doi.org/10.1016/j.gloplacha.2012.08.008

b) Lowell Stott, Axel Timmermann, Robert Thunell: Southern hemisphere and deep-sea warming led deglacial atmospheric CO2 rise and tropical warming, Science, (19 October 2007) Vol. 318 no. 5849 pp. 435-438. DOI:10.1126/science.1143791

c) Manfred Mudelsee: The phase relations among atmospheric CO2 content, temperature and global ice volume over the past 420 ka, Quaternary Science Reviews, (February 2001) Volume 20, Issue 4, Pages 583–589. http://dx.doi.org/10.1016/S0277-3791(00)00167-0

d) Bärbel Hönisch, N. Gary Hemming, David Archer, Mark Siddall, Jerry F. McManus: Atmospheric carbon dioxide concentration across the mid-Pleistocene transition, Science, (19 June 2009) Vol. 324, no. 5934, pp.1551-1554 . DOI:10.1126/science.1171477

4) BUT IF CO2 ISN'T DRIVING CLIMATE CHANGE, WHAT IS? - Climate change throughout human history closely follows solar activity cycles.

a) C. de Jager, S. Duhau: Episodes of relative global warming, Journal of Atmospheric and Solar-Terrestrial Physics, (2009) vol. 71, no. 2, pp.194-198. DOI:10.1016/j.jastp.2008.11.013

b) Graeme T. Swindles, R. Timothy Patterson, Helen M. Roe, Jennifer M. Galloway: Evaluating periodicities in peat-based climate proxy records, Quaternary Science Reviews, (18 May 2012) Volume 41, pp.94–103. http://dx.doi.org/10.1016/j.quascirev.2012.03.003

c) Jinglu Wu, Zicheng Yu, Hai'Ao Zeng, Ninglian Wang: Possible solar forcing of 400-year wet-dry climate cycles in northwestern China, Climatic Change, (2009) vol.96:473-482. DOI:10.1007/s10584-009-9604-4

d) Ilya G. Usokin, Sami K. Solanki, Manfred Schüssler: Millennium-scale sunspot number reconstruction: evidence for an unusually active Sun since the 1940s, Physical Review Letters [American Physical Society], (19 November 2003) Vol. 91, Issue 21 DOI:10.1103/PhysRevLett.91.211101

5) BUT HOW CAN A NEAR-CONSTANT SUN DRIVE LARGE CHANGES IN CLIMATE? – Mechanisms exist which can turn minor solar variations into large climate impacts on both regional and global scales.

a) Mukul Sharma: Variations in solar magnetic activity during the last 200,000 years: is there a Sun–climate connection?, Earth and Planetary Science Letters, (10 June 2002) Volume 199, Issues 3–4, pp.459–472. http://dx.doi.org/10.1016/S0012-821X(02)00516-2

b) Murry Salby, Patrick Callaghan: Connection between the solar cycle and the QBO: the missing link, Journal of Climate [American Meteorological Society], (January 2000) Volume 13, Issue 2, pp.328–338.  http://journals.ametsoc.org/doi/full/10.1175/1520-0442%282000%29013%3C03...

c) Gerald A. Meehl, Julie M. Arblaster, Katja Matthes, Fabrizio Sassi, Harry van Loon: Amplifying the Pacific climate system response to a small 11-year solar cycle forcing, Science (28 August 2009) Vol. 325, no. 5944, pp.1114-1118. DOI:10.1126/science.1172872

d) B. Kirov, K. Georgieva: Long-term variations and interrelations of ENSO, NAO and solar activity, Physics and Chemistry of the Earth, Parts A/B/C, (2002) Volume 27, Issues 6-8, pp.441-448. http://dx.doi.org/10.1016/S1474-7065(02)00024-4

Bonus) BUT ISN'T LESS CO2 BETTER FOR US ALL ANYWAY? - CO2 is a trace gas, non-toxic to human beings, which is essential to plant life in particular and to the biosphere as a whole. Increased atmospheric CO2 levels benefit the entire biosphere.

a) Anabel Robredo, Usue Pérez-López, Hector Sainz de la Maza, Begoña González-Moro, Maite Lacuesta, Amaia Mena-Petite, Alberto Muñoz-Rueda: Elevated CO2 alleviates the impact of drought on barley improving water status by lowering stomatal conductance and delaying its effects on photosynthesis, Environmental and Experimental Botany, (April 2007) Volume 59, Issue 3, pp.252–263. http://dx.doi.org/10.1016/j.envexpbot.2006.01.001

b) Heather R. McCarthy, Ram Oren, Hyun-Seok Kim, Kurt H. Johnson, Chris Maier, Seth G. Pritchard, Micheal A. Davis: Interaction of ice storms and management practices on current carbon sequestration in forests with potential mitigation under future CO2 atmosphere, Journal of Geophysical Research, (08 August 2006) Vol. 111, D15103. DOI:10.1029/2005JD006428

c) Shannon L. LaDeau, James S. Clark: Rising CO2 levels and the fecundity of forest trees, Science, (06 April 2001) Vol. 292, no. 5514, pp.95-98. DOI:10.1126/science.1057547

d) G. Geoff Wang, Sophan Chhin, William L. Bauerle: Effect of natural atmospheric CO2 fertilization suggested by open-grown white spruce in a dry environment, Global Change Biology, (March 2006) Volume 12, Issue 3, pp.601–610. Available online 17 January 2006. DOI:10.1111/j.1365-2486.

IN SUMMARY:

It has been proclaimed far and wide that the “mainstream” scientific consensus has “settled” in favor of AGW, but as you can see from this small sample, that is simply not the case. If this is not enough peer-reviewed science to persuade you of a genuine debate, try out this list of papers, among others: http://www.populartechnology.net/2009/10/peer-reviewed-papers-supporting.html. There’s enough there to keep you busy for a little while.

If you review the science and still come to the conclusion that Mankind is to blame for the warming of our climate, that's fine with me. You’ll need to be okay with not understanding why CO2 lags temperature, why its predicted effects do not match observed climate measurements, or why the IPCC's general circulation models cannot predict short-term, regional, or even past climate changes accurately.

By the same token, those who come to the conclusion that AGW is "wrong" have to explain why the urban heat island effect doesn't significantly influence regional or global climate; why observed climate changes are far larger than changes in total solar irradiance can account for; and why it is unreasonable to assume that human civilization has a measurable affect on regional/global climates, when atmospheric evidence of that civilization is observable from beyond Lunar orbit.

Both sides have plausible answers to those questions, and as I've said, a reasoned decision either way is fine with me, as long as it's based on your best understanding of the information. Basing your decision solely on political concerns is probably not a good idea, though you certainly can if you want.

But hopefully you can now see for yourself that when it comes to climate change, anyone who tells you that the science is "settled," "well understood" or "decided" probably has not seen the evidence, or just doesn’t want you to see it.

So, Brian: what do you like for lunch?

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