1... taxes are not market driven solution. the market responds to taxes. 2. before it might make sense for the govt to get involved... should there not be some evidence... a. that we are warming outside of natural variablility b. that man made co2 is responsible for co2 accumulation and not ocean warming? c. that man made co2 is causing warming? The govts job is to protect us from real foes... by sealing our borders and opposing isis. we don't need taxes to protect us from plant food without real science showing man made co2 to be a threat.
More bullshit sources from the denier liars. When one sees the term "alarmist", one can stop reading. Fact is that a rapidly changing climate and weather is deleterious to agricultural and natural systems. Life is where it is because it is adapted to the conditions there. When those conditions change the living stuff there suffers. You're another one that better stay off the road. Scumbag.
Fraudcurrents has gone so far off the charts he is now calling a boston university press release of a NASA study a bullshit source? you are such a troll fraudcurrents. Are you denying that some scientists at NASA think that adding co2 would cause plant growth?
to which cycle of warming are you referring? the warming that happen for about 20 years... 18 years ago? How do you know that was not natural? How do you know it was caused by man made c02 when it was just like the warming in the previous cycle? and don't go trying to use that now debunked hockey stick... recent studies are proving the midieval warm period was as warm or warmer than today. just click back a few pages.
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.
you are citing stale studies... I just listed the recent ones for you... here are a few... http://www.sciencemag.org/content/342/6158/617 Observed increases in ocean heat content (OHC) and temperature are robust indicators of global warming during the past several decades. We used high-resolution proxy records from sediment cores to extend these observations in the Pacific 10,000 years beyond the instrumental record. We show that water masses linked to North Pacific and Antarctic intermediate waters were warmer by 2.1 ± 0.4°C and 1.5 ± 0.4°C, respectively, during the middle Holocene Thermal Maximum than over the past century. Both water masses were ~0.9°C warmer during the Medieval Warm period than during the Little Ice Age and ~0.65° warmer than in recent decades. Although documented changes in global surface temperatures during the Holocene and Common era are relatively small, the concomitant changes in OHC are large.[/quote]
the arctic was warmer too.... http://www.co2science.org/subject/m/summaries/mwparctic.php Medieval Warm Period (Arctic) -- Summary ... Working concurrently on a floating platform in the middle of a small lake (Hjort So) on an 80-km-long by 10.5-km-wide island (Store Koldewey) just off the coast of Northeast Greenland, Wagner et al. (2008) recovered two sediment cores of 70 and 252 cm length, the incremental portions of which they analyzed for grain-size distribution, macrofossils, pollen, diatoms, total carbon, total organic carbon, and several other parameters, the sequences of which were dated by accelerator mass spectrometry, with radiocarbon ages translated into calendar years before present. This work revealed, as they describe it, an "increase of the productivity-indicating proxies around 1,500-1,000 cal year BP, corresponding with the medieval warming," while adding that "after the medieval warming, renewed cooling is reflected in decreasing amounts of total organic carbon, total diatom abundance, and other organisms, and a higher abundance of oligotrophic to meso-oligotrophic diatom taxa." And, as they continue, "this period, the Little Ice Age, was the culmination of cool conditions during the Holocene and is documented in many other records from East and Northeast Greenland, before the onset of the recent warming [that] started ca. 150 years ago." In addition to the obvious importance of their finding evidence for the Medieval Warm Period, the six researchers' statement that the Little Ice Age was the culmination, or most extreme sub-set, of cool conditions during the Holocene, suggests that it would not be at all unusual for such a descent into extreme coolness to be followed by some extreme warming, which further suggests there is nothing unusual about the degree of subsequent warming experienced over the 20th century, especially in light of the fact that the earth has not yet achieved the degree of warmth that held sway over most of the planet throughout large portions of that prior high-temperature period. One year later, based on the use of a novel biomarker (IP25), which they described as a mono-unsaturated highly-branched isoprenoid that is synthesized by sea ice diatoms that have been shown to be stable in sediments below Arctic sea ice, Vare et al. (2009) used this new climatic reconstruction tool - together with "proxy data obtained from analysis of other organic biomarkers, stable isotope composition of bulk organic matter, benthic foraminifera, particle size distributions and ratios of inorganic elements" - to develop a spring sea ice record for that part of the central Canadian Arctic Archipelago. And in doing so, they discovered evidence for a decrease in spring sea ice between approximately 1200 and 800 years before present (BP), which they associated with "the so-called Mediaeval Warm Period." Contemporaneously, Norgaard-Pedersen and Mikkelsen (2009), working with a sediment core retrieved in August 2006 from the deepest basin of Narsaq Sound in southern Greenland, analyzed several properties of the materials thus obtained from which they were able to infer various "glacio-marine environmental and climatic changes" that had occurred over the prior 8,000 years. This work revealed the existence of two periods (2.3-1.5 ka and 1.2-0.8 ka) that appeared to coincide roughly with the Roman and Medieval Warm Periods, while they identified the colder period that followed the Medieval Warm Period as the Little Ice Age and the colder period that preceded it as the Dark Ages Cold Period. And citing the works of Dahl-Jensen et al. (1998), Andresen et al. (2004), Jensen et al. (2004) and Lassen et al. (2004), the two Danish scientists said that the cold and warm periods identified in those researchers' studies "appear to be more or less synchronous to the inferred cold and warm periods observed in the Narsaq Sound record," providing ever more evidence for the reality of the naturally-occurring phenomenon that governs this millennial-scale oscillation of climate. One year later, Vinther et al. (2010) analyzed 20 ice core records from 14 different sites, all of which stretched at least 200 years back in time, as well as near-surface air temperature data from 13 locations along the southern and western coasts of Greenland that covered approximately the same time interval (1784-2005), plus a similar temperature data set from northwest Iceland (said by the authors to be employed "in order to have some data indicative of climate east of the Greenland ice sheet"). This work demonstrated that winter ð18O was "the best proxy for Greenland temperatures." And based on that determination and working with three longer ice core ð18O records (DYE-3, Crete and GRIP), they developed a temperature history that extended more than 1400 years back in time. This history revealed, in the words of the seven scientists, that "temperatures during the warmest intervals of the Medieval Warm Period" - which they defined as occurring some 900 to 1300 years ago - "were as warm as or slightly warmer than present day Greenland temperatures." As for what this result implies, they state that further warming of present day Greenland climate "will result in temperature conditions that are warmer than anything seen in the past 1400 years," which, of course, has not happened yet. Furthermore, Vinther et al. readily acknowledge that the independent "GRIP borehole temperature inversion suggests that central Greenland temperatures are still somewhat below the high temperatures that existed during the Medieval Warm Period." About this same time, Kobashi et al. (2010) had a paper published in which they had written that "in Greenland, oxygen isotopes of ice (Stuiver et al., 1995) have been extensively used as a temperature proxy, but the data are noisy and do not clearly show multi-centennial trends for the last 1,000 years in contrast to borehole temperature records that show a clear 'Little Ice Age' and 'Medieval Warm Period' (Dahl-Jensen et al., 1998)." However, they went on to note that nitrogen (N) and argon (Ar) isotopic ratios - 15N/14N and 40Ar/36Ar, respectively - can be used to construct a temperature record that "is not seasonally biased, and does not require any calibration to instrumental records, and resolves decadal to centennial temperature fluctuations." much more...[/quote]
there are multiple studies showing the Mideval warm period was global. I just cited one above... here is another... http://hockeyschtick.blogspot.com/2010/01/blog-post_26.html Mann upset about paper in Science suggesting Medieval Warm Period was global A 2001 article in Science entitled "Was the Medieval Warm Period Global?" states ,"The Little Ice Age and the subsequent warming were global in extent... Borehole records both in polar ice and in wells fromall continents suggest the existence of a Medieval Warm Period." From the conclusions of the Science paper: "The geographic pattern of Holocene climate fluctuations remains murky, but several things are clear. The Little Ice Age and the subsequent warming were global in extent. Several Holocene fluctuations in snowline, comparable in magnitude to that of the post-Little Ice Age warming, occurred in the Swiss Alps. Borehole records both in polar ice and in wells from all continents suggest the existence of a Medieval Warm Period. Finally, two multidecade-duration droughts plagued the western United States during the latter part of the Medieval Warm Period. I consider this evidence sufficiently convincing to merit an intensification of studies aimed at elucidating Holocene climate fluctuations, upon which the warming due to greenhouse gases is superimposed."This paper also prompted an internet posting critical of Michael Mann's hockey stick paper, which concludes, "global warming is natural and the recent warming is probably no exception." The Climategate emails include two email exchanges here and here in which Mann appears to be infuriated with the suggestion that the MWP was global and well as any suggestion that the current warm period was similar. This article prompted the following entry at a now defunct site (climatechangedebate.org) which is quoted in full in the above climategate emails: Climate Guru Kicks The Hockey Stick by David Wqjick... Global warming is natural and the recent warming is probably no exception. This is the controversial argument made by prominent climatologist Wallace S. Broecker in today’s issue of Science. Broecker’s bombshell bears the seemingly innocent title “Was the Medieval Warm Period Global?” It may seem esoteric, but whether the apparent warmth reported in Europe about 1000 years ago was global or simply local is becoming a central issue in climate science. What makes it contentious is the recent claims by the Umted Nations Intergovernmental Panel on Climate Change that the earth is warmer now than it has been for millennia, and that therefore human carbon dioxide emissions are to blame. Broecker, a leading figure at Lamont-Doherty Earth Observatory, Columbia University, questions both IPCC claims. The focus of the debate is a 1OOO-year temperature reconstruction known in climate circles as the “hockey stick”. Produced in 1999 by M. E. Mann, R. S. Bradley, M. K. Hughes, the long handle of the hockey stick shows global temperatures for the first 8 centuries as basically unchanging, followed by the sharply up-tilting blade of the last 150 years or so. The Mann et al hockey stick is the central feature of the recently released IPCC working group one Summary for Policy makers, which claims to embody the best of climate science. Broecker does not like the hockey stick, nor the conclusions the IPCC draw from it. He says ” A recent, widely cited reconstruction (Mann’s) leaves the impression that the 20th century warming was unique during the last millennium. It shows no hint of the Medieval Warm Period (from around 800 to 1200 A.D.) during which the Vikings colonized Greenland, suggesting that this warm event was regional rather than global. It also remains unclear why just at the dawn of the Industrial Revolution and before the emission of substantial amounts of anthropogenic greenhouse gases, Earth’s temperature began to rise steeply. Was it a coincidence? I do not think so. Rather, I suspect that the post-1860 natural warming was the most recent in a series of similar warmings spaced at roughly 1500-year intervals throughout the present inter-glacial, the Holocene.” Broecker presents the evidence for a global Medieval Warm Period, as well as for a Little Ice Age from around 1300 to 1860, when the present temperature rise begins. He also argues that the “proxy” evidence used by Mann et al, such as tree ring data, is ill suited to the time period and temperature variation -- less than one degree C -- in question. As he puts it, “In my estimation, at least for time scales greater than a century or two, only two proxies can yield temperatures that are accurate to 0.5 C: the reconstruction of temperatures from the elevation of mountain snowlines and borehole thermometry. Tree ring records are useful for measuring temperature fluctuations over short time periods but cannot pick up long-term trends because there is no way to establish the long-term evolution in ring thickness were temperatures to have remained constant.”[/quote]