What evidence is there for the hockey stick? Link to this page What the science says... Since the hockey stick paper in 1998, there have been a number of proxy studies analysing a variety of different sources including corals, stalagmites, tree rings, boreholes and ice cores. They all confirm the original hockey stick conclusion: the 20th century is the warmest in the last 1000 years and that warming was most dramatic after 1920. Climate Myth... Hockey stick is broken “In 2003 Professor McKitrick teamed with a Canadian engineer, Steve McIntyre, in attempting to replicate the chart and finally debunked it as statistical nonsense. They revealed how the chart was derived from "collation errors, unjustified truncation or extrapolation of source data, obsolete data, incorrect principal component calculations, geographical mislocations and other serious defects" -- substantially affecting the temperature index.” (John McLaughlin) The "hockey stick" describes a reconstruction of past temperature over the past 1000 to 2000 years using tree-rings, ice cores, coral and other records that act as proxies for temperature (Mann 1999). The reconstruction found that global temperature gradually cooled over the last 1000 years with a sharp upturn in the 20th Century. The principal result from the hockey stick is that global temperatures over the last few decades are the warmest in the last 1000 years. Figure 1: Northern Hemisphere temperature changes estimated from various proxy records shown in blue (Mann 1999). Instrumental data shown in red. Note the large uncertainty(grey area) as you go further back in time. A critique of the hockey stick was published in 2004 (McIntyre 2004), claiming the hockey stick shape was the inevitable result of the statistical method used (principal components analysis). They also claimed temperatures over the 15th Century were derived from one bristlecone pine proxy record. They concluded that the hockey stick shape was not statistically significant. An independent assessment of Mann's hockey stick was conducted by the National Center for Atmospheric Research (Wahl 2007). They reconstructed temperatures employing a variety of statistical techniques (with and without principal components analysis). Their results found slightly different temperatures in the early 15th Century. However, they confirmed the principal results of the original hockey stick - that the warming trend and temperatures over the last few decades are unprecedented over at least the last 600 years. Figure 2: Original hockey stick graph (blue - MBH1998) compared to Wahl & Ammannreconstruction (red). Instrumental record in black (Wahl 2007). While many continue to fixate on Mann's early work on proxy records, the science of paleoclimatology has moved on. Since 1999, there have been many independentreconstructions of past temperatures, using a variety of proxy data and a number of different methodologies. All find the same result - that the last few decades are the hottest in the last 500 to 2000 years (depending on how far back the reconstruction goes). What are some of the proxies that are used to determine past temperature? Changes in surface temperature send thermal waves underground, cooling or warming the subterranean rock. To track these changes, underground temperature measurements were examined from over 350 bore holes in North America, Europe, Southern Africa and Australia (Huang 2000). Borehole reconstructions aren't able to give short term variation, yielding only century-scale trends. What they find is that the 20th century is the warmest of the past five centuries with the strongest warming trend in 500 years. Figure 3: Global surface temperature change over the last five centuries from boreholes (thick red line). Shading represents uncertainty. Blue line is a five year running average ofHadCRUT global surface air temperature (Huang 2000). Stalagmites (or speleothems) are formed from groundwater within underground caverns. As they're annually banded, the thickness of the layers can be used as climate proxies. Areconstruction of Northern Hemisphere temperature from stalagmites shows that while theuncertainty range (grey area) is significant, the temperature in the latter 20th Century exceeds the maximum estimate over the past 500 years (Smith 2006). Figure 4: Northern Hemisphere annual temperature reconstruction from speleothemreconstructions shown with 2 standard error (shaded area) (Smith 2006). Historical records of glacier length can be used as a proxy for temperature. As the number of monitored glaciers diminishes in the past, the uncertainty grows accordingly. Nevertheless, temperatures in recent decades exceed the uncertainty range over the past 400 years (Oerlemans 2005). Figure 5: Global mean temperature calculated form glaciers. The red vertical lines indicateuncertainty. Of course, these examples only go back around 500 years - this doesn't even cover theMedieval Warm Period. When you combine all the various proxies, including ice cores, coral, lake sediments, glaciers, boreholes & stalagmites, it's possible to reconstruct Northern Hemisphere temperatures without tree-ring proxies going back 1,300 years (Mann 2008). The result is that temperatures in recent decades exceed the maximum proxyestimate (including uncertainty range) for the past 1,300 years. When you include tree-ring data, the same result holds for the past 1,700 years. Figure 6: Composite Northern Hemisphere land and land plus ocean temperaturereconstructions and estimated 95% confidence intervals. Shown for comparison are published Northern Hemisphere reconstructions (Mann 2008). Paleoclimatology draws upon a range of proxies and methodologies to calculate past temperatures. This allows independent confirmation of the basic hockey stick result: that the past few decades are the hottest in the past 1,300 years.
In fairness to Dr. Mann, his 2008 reconstruction did restore the Medieval Warm Period and Little Ice Age to their proper places; but he still used Mike’s Nature Trick to slap a hockey stick blade onto the 20th century. What happens if we use the plant stomata-derived CO2 instead of the ice core data? We find that the ~250-year lag time is consistent. CO2 levels peaked 250 years after the Medieval Warm Period peaked and the Little Ice Age cooling began and CO2 bottomed out 240 years after the trough of the Little Ice Age. In a fashion similar to the glacial/interglacial lags in the ice cores, the plant stomata data indicate that CO2 has lagged behind temperature changes by about 250 years over the last millennium. The rise in CO2 that began in 1860 is most likely the result of warming oceans degassing. While we don’t have a continuous stomata record over the Holocene, it does appear that a lag time was also present in the early Holocene… http://wattsupwiththat.com/2010/12/26/co2-ice-cores-vs-plant-stomata/
American Physical Society "The evidence is incontrovertible: Global warming is occurring. If no mitigating actions are taken, significant disruptions in the Earth’s physical and ecological systems, social systems, security and human health are likely to occur. We must reduce emissions of greenhouse gases beginning now."
Willard Anthony Watts is a former radio and TV weatherman and notable global warming denier. He claims to have subscribed to AGW years ago before he saw the light and became a denier. He also claims that he is (otherwise) an environmentalist. This makes him something of an AGW concern troll. He is the proprietor of the Jerry Seinfeldian Watts Up With That (geddit?) blog, usually shortened to WUWT or, as it is sometimes affectionately nicknamed, LOLWUWT orWTFUWT. In the wake of Steve McIntyre of Cimate (Fr)audit fame co-winning the 2007 Best Science Blog prize, the contest yet again made a mockery of itself by giving Watts the same award in 2008. He also runs Surface Stations, a database of pictures and data on weather stations. Although Watts has made appearances on both Glenn Beck[1] and Sean Hannity's[2] shows, he is among the less nutty of the prominent deniers. Mostly he just repeats the same tired old denier talking points, or pulls out some random data and says, "Look, it's cold somewhere!"
Oh, and twatts is a paid for whore also. Bought and paid for by the fossil fuel interests. So of course jerm and piehole (same person?) often refer to his propaganda website.
sadly for you... Watts links to real science and real studies. your brain does not even allow you to understand that you have no proof that man made co2 causes warming.
Mark Steyn writes: [Tuesday] marked a not unimportant court deadline in the upcoming Mann vs Steyn trial of the century, and I wouldn’t want to let it pass without comment. Ever since this tedious suit was launched by Doctor Fraudpants in defense of his global-warming hockey stick, Michael Mann’s supporters have insisted that it’s not, as I and my fellow defendants have insisted, about free speech. Instead, as they see it, it’s about science finally fighting back against a sustained assault by Koch-funded “denialists”. This sub-headline encapsulates the general line: Michael Mann is taking a stand for science. Gotcha. Michael Mann is not doing this for Michael Mann, or even for Michael Mann’s science, or even for climate science. He’s doing it for science. Mann is science and science is Mann. A few weeks ago, you’ll recall, the ACLU, The Washington Post, NBC News, The Los Angeles Times and various other notorious right-wing deniers all filed amici briefs opposed to Michael Mann and his assault on free speech. They did this not because they have any great love for me, but because their antipathy to wackjob foreign blowhards is outweighed by their appreciation of the First Amendment – and an understanding of the damage a Mann victory would inflict on it. After noting the upsurge of opposition to Mann, Reuters enquired of Catherine Reilly (one of his vast legal team) whether there would be any amici filing pro-Mann briefs: I asked Reilly if the professor would have any supporting briefs next month when he responds to the defendants in the D.C. appeals court. “At this point, we don’t know,” she said. Ms Reilly was a pleasant sort when I met her in court over a year ago, but she struck me as a formidable opponent. So I naturally assumed that the above was what what the political types call “lowering expectations”. As I wrote: I would be surprised if Mann didn’t have any supporting briefs. I was in court when Ms Reilly’s genial co-counsel made his argument for Mann, which was a straightforward appeal to authority: Why, all these eminent acronymic bodies, from the EPA and NSF and NOAA even unto HMG in London, have proved that all criticisms of Mann are false and without merit. So I would certainly expect them to file briefs – and, given that Mann sees this as part of a broader “war on science” by well-funded “deniers”, I would also expect briefs from the various professional bodies: the National Academy of Sciences, the American Physical Society, etc. As pleasant as it is to find my side of the court suddenly so crowded, I’m confident Mann will be able to even up the numbers. Well, yesterday was the deadline, and not a single amicus brief was filed on behalf of Mann. Not one. So Michael Mann is taking a stand for science. But evidently science is disinclined to take a stand for Michael Mann. The self-appointed captain of the hockey team is playing solo. As Judith Curry wrote last month: The link between ‘defending Michael Mann is defending climate science’ seems to have been broken. As yesterday’s deafening silence confirms. If you’re defending Michael Mann, you’re not defending science, or defending climate science, or theories on global warming or anything else. Defending Michael Mann means defending Michael Mann – and it turns out not many people are willing to go there. =========================================== More here: http://www.steynonline.com/6565/the-lonesomest-mann-in-town
Consensus: 97% of climate scientists agree Temperature data from four international science institutions. All show rapid warming in the past few decades and that the last decade has been the warmest on record. 3091and most of the leading scientific organizations worldwide have issued public statements endorsing this position. The following is a partial list of these organizations, along with links to their published statements and a selection of related resources. AMERICAN SCIENTIFIC SOCIETIES Statement on climate change from 18 scientific associations "Observations throughout the world make it clear that climate change is occurring, and rigorous scientific research demonstrates that the greenhouse gases emitted by human activities are the primary driver." (2009)2 American Association for the Advancement of Science "The scientific evidence is clear: global climate change caused by human activities is occurring now, and it is a growing threat to society." (2006)3 American Chemical Society "Comprehensive scientific assessments of our current and potential future climates clearly indicate that climate change is real, largely attributable to emissions from human activities, and potentially a very serious problem." (2004)4 American Geophysical Union "Human‐induced climate change requires urgent action. Humanity is the major influence on the global climate change observed over the past 50 years. Rapid societal responses can significantly lessen negative outcomes." (Adopted 2003, revised and reaffirmed 2007, 2012, 2013)5 American Medical Association "Our AMA ... supports the findings of the Intergovernmental Panel on Climate Change’s fourth assessment report and concurs with the scientific consensus that the Earth is undergoing adverse global climate change and that anthropogenic contributions are significant." (2013)6 American Meteorological Society "It is clear from extensive scientific evidence that the dominant cause of the rapid change in climate of the past half century is human-induced increases in the amount of atmospheric greenhouse gases, including carbon dioxide (CO2), chlorofluorocarbons, methane, and nitrous oxide." (2012)7 American Physical Society "The evidence is incontrovertible: Global warming is occurring. If no mitigating actions are taken, significant disruptions in the Earth’s physical and ecological systems, social systems, security and human health are likely to occur. We must reduce emissions of greenhouse gases beginning now." (2007)8 The Geological Society of America "The Geological Society of America (GSA) concurs with assessments by the National Academies of Science (2005), the National Research Council (2006), and the Intergovernmental Panel on Climate Change (IPCC, 2007) that global climate has warmed and that human activities (mainly greenhouse‐gas emissions) account for most of the warming since the middle 1900s." (2006; revised 2010)9 SCIENCE ACADEMIES International academies: Joint statement "Climate change is real. There will always be uncertainty in understanding a system as complex as the world’s climate. However there is now strong evidence that significant global warming is occurring. The evidence comes from direct measurements of rising surface air temperatures and subsurface ocean temperatures and from phenomena such as increases in average global sea levels, retreating glaciers, and changes to many physical and biological systems. It is likely that most of the warming in recent decades can be attributed to human activities (IPCC 2001)." (2005, 11 international science academies)10 U.S. National Academy of Sciences "The scientific understanding of climate change is now sufficiently clear to justify taking steps to reduce the amount of greenhouse gases in the atmosphere." (2005)11 U.S. GOVERNMENT AGENCIES U.S. Global Change Research Program "The global warming of the past 50 years is due primarily to human-induced increases in heat-trapping gases. Human 'fingerprints' also have been identified in many other aspects of the climate system, including changes in ocean heat content, precipitation, atmospheric moisture, and Arctic sea ice." (2009, 13 U.S. government departments and agencies)12