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Topic: MWP and LIA in IPCC reports

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Medieval climate optimum

Little Ice Age

John Huss

Burned at the stake

Black Death

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Giordano Bruno

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	MWP and LIA in IPCC reports - Wikipedia, the free encyclopedia
		It is sometimes claimed that the MWP or LIA have been airbrushed out of the 2001 IPCC Third Assessment Report whilst being prominently featured in earlier reports [1].
		The MWP is not mentioned at all, and the LIA described by...probably fluctuated by little more than 1°C. Some fluctuations lasted several centuries, including the LIA which ended in the [19th century] and which appears to have been global in extent.
		The 1995 IPCC report used a northern hemisphere summer temperature reconstruction (fig 3.20) from 1400 to 1979 by Bradley and Jones (1993).
	en.wikipedia.org /wiki/MWP_and_LIA_in_IPCC_reports (851 words)

	Pseudo science in climate research
		In the maps of world temperature trends that IPCC presents (IPCC 2001a, p 116 and IPCC 2001c, p 27), the period 1976-2000 is the last.
		According to the latest reports by IPCC, the expected global warming up to the year 2100 is 1.5-5.8 °C. This in spite of IPCC actually counts on the possibility that the CO concentration will not double (IPCC 2001a, appendix II).
		One thing entirely missing in the reports from IPCC is a comparison between the CO models and the real increase of carbon dioxide in the past.
	www.astro.uu.se /~l/klipseue.html (4317 words)

	NEW ON THE SEPP WEB
		As part of our emergence from the LIA, scientists agreed there had been a gradual warming throughout the 20th century, although the reasons for this were hotly contested with increasing greenhouse gases (GHG) and changes in the output of the sun being leading contenders.
		This was especially true since long-term solar records indicated that both the MWP and LIA were closely correlated with changes in solar activity, and the output of the sun has indeed been increasing during the past century's 0.6C warming.
		Willie Soon and Sallie Baliunas of the Harvard Institute of Astrophysics added to the critique of Mann's hockey stick in March of this year when they showed that a careful analysis of 240 proxy studies reaffirmed that the MWP and the LIA were indeed worldwide phenomena, not limited to the European and North American continents.
	www.his.com /~sepp/Archive/NewSEPP/Kyoto-Patterson.htm (1122 words)

	Reference.com/Encyclopedia/Medieval Warm Period
		The MWP is often invoked in contentious discussions of global warming and the greenhouse effect.
		Initial research on the MWP and the following Little Ice Age (LIA) was largely done in Europe, where the phenomenon was most obvious and clearly documented.
		The core clearly shows a distinctly cold period about AD 1000–1100, nicely illustrating the fact that "MWP" is a moveable term, and that during the "warm" period there were, regionally, periods of both warmth and cold.
	www.reference.com /browse/wiki/Medieval_Warm_Period (726 words)

	The Carbon Challenge: should Australia decarbonise ?
		The report from the UN Intergovernmental Panel on Climate Change (IPCC) is described as the most comprehensive study on the subject to date and warns of large-scale and irreversible climate changes, of devastating droughts, floods, violent storms in addition to the spread of cholera and malaria.
		This Report’s first Figure (Figure 1 herein) shows a ‘normal’ range of CO2 concentration in the atmosphere of 180-280 ppmv over the last 400,000 years, rising steeply to the present 370 ppm, and skyrocketing to a projected 660 ppm by AD 2100.
		Two of the most crucial put out by IPCC, at least in terms of their attention-getting, are that the 20th century is the warmest in the last 1000 years, and that up to 6 degrees C of additional warming is predicted by AD 2100.
	www.warwickhughes.com /climate/decarb.htm (11181 words)

	The fabled hockey stick graph. Text - Physics Forums Library
		The reason why the MWP and the LIA had to dissapear is that they did not match the CO2 record and the objective of the hockeystick was to prove that CO2 is the main, sole and only primary driver for climate.
		The IPCC’s use of the hockey stick was not incidental: it is prominent throughout the 2001 report.
		He discusses the main conclusions of the three IPCC reports and the predicted impact on global temperatures, rainfall, weather and climate, while highlighting the mounting confusion and sensationalism of reports in the media.
	www.physicsforums.com /archive/index.php/t-94621.html (4652 words)

	RealClimate » Moberg et al: Highly variable Northern Hemisphere temperatures? Moberg et coll. : une plus grande ...
		Of course, the mere fact that the "totemizing" was propagated by the IPCC, the environmental lobby and especially the authors of this blog as "the scientific consensus" should cause disinterested viewers to wonder as to who is trying to fool who.
		The number I quoted is from a new study (still in press), but is similar to that reported (2.6) for a model with the same atmospheric component in IPCC (2001).
		Of course I've seen the often used IPCC TAR result here showing that modelling results combining natural and anthropogenic forcings reproduce 20th century global mean surface temperature anomalies relative to the 1880 to 1920 mean.
	www.realclimate.org /index.php?p=122 (8151 words)

	Deltoid: The Australian's War on Science
		They did not report anything when the hockey stick study was published or when it was included in the TAR or publish anything supportive of it.
		Because the Wegman report was commissioned for an obviously partisan purpose by Joe Barton, and because the non-partisan NRC report had already covered the same ground and then some, Wegman's report has been ignored by the media.
		In this report we have focused on answering this question and not on whether or not the global climate is changing.
	scienceblogs.com /deltoid/2006/07/the_australians_war_on_science.php (4665 words)

	Global Warming Stories - John L. Daly
		But the IPCC and the National Assessment went with the Hockey Stick, globalising what was meant to be a northern hemisphere study, turning a blind eye to the large error ranges involved, and are now in a state of denial about the sun's role in climate change.
		The IPCC and the environmentalists have for years kept the public focus only on a tiny area of the Antarctic, the Antarctic Peninsula, a mere 2% of the total area of the continent.
		report on ocean temperatures, this is strongly subject to `end date distortion' as the starting year for that record was 1948, the early part of a particularly cold period which ended around 1976.
	www.john-daly.com /press/press-02a.htm (12444 words)

	Global Warming - The Naked Scientists Science Discussion Forum
		The Medieval Warm Period (MWP) or Medieval Climate Optimum was an unusually warm period during the European Medieval period, lasting from about the 10th century to about the 14th century.
		The MWP is often involved in contentious discussions of global warming and the greenhouse effect.
		Tropical reefs tend to show temperature increases of less than 1 °C. In terms of the global average, the typical shift was probably between 0.5 and 2 °C warmer than the mid-20th century (depending on estimates of latitude dependence and seasonality in response patterns).
	www.thenakedscientists.com /forum/index.php?topic=4436.msg35286 (5571 words)

	Global Warming Stories 2000 - John L. Daly
		In their report, the IPCC have replaced the small number of global warming scenarios outlined in their previous reports in 1991 and 1995 and instead produced a plethora of scenarios, divided into `families'.
		But the MWP and LIA are both alive and well in proxy records like lake beds, sea bed cores, lake levels, corals, and tree rings from all over the world.
		This is contrary to claims by the IPCC and the National Assessment that the past millenium was one of steady and benign climate until the 20th century.
	www.john-daly.com /press/press-00b.htm (13414 words)

	RealClimate » What If … the “Hockey Stick” Were Wrong? Et si …. la “Crosse de ...
		The IPCC gives the uncertainty range as 1.5-4.5 ºC. Only if this is wrong, and the true value is lower, can we escape the fact that unabated emissions of greenhouse gases will lead to the warming projected by the IPCC.
		In some media reports, the “hockey stick” has even been hyped as “a pillar of the Kyoto protocol” (which was agreed in 1997 and thus predates it) or as “proof that humans are warming the Earth”.
		You confuse the IPCC climate sensitivity range (1.5-4.5 C) with the estimates of temperatures in 2100 (1.4 to 5.8 C).
	www.realclimate.org /index.php?p=114 (9089 words)

	Medieval Warm Period - Wikipedia, the free encyclopedia
		The Medieval Warm Period (MWP) or Medieval Climate Optimum was a time of unusually warm climate in the North Atlantic region, lasting from about the tenth century to about the fourteenth century.
		Some "MWP" events are thus wet events or cold events rather than strictly warm events, particularly in central Antarctica where climate patterns opposite to the North Atlantic area have been noticed.
		The MWP was followed by the Little Ice Age, a period of cooling that lasted until the 19th century when the current period of global warming began.
	en.wikipedia.org /wiki/MWP (921 words)

	Stoat
		The HoS reported in early July 2005; co-incidentally the "Chancellor announced on 19 July 2005 that he had asked Sir Nick Stern to lead a major review of the economics of climate change, to understand more comprehensively the nature of the economic challenges and how they can be met, in the UK and globally.
		So (a) its not news; anything in the report (should!) have been said a year ago; and (b) I don't recall the Exeter conf saying much new at the time, either (backed up by the RC post I wrote at the time).
		The climate centres around the world, which are the equivalent of the pathology lab of a hospital, have reported the Earth's physical condition, and the climate specialists see it as seriously ill, and soon to pass into a morbid fever that may last as long as 100,000 years.
	mustelid.blogspot.com (10650 words)

	Common Sense Technology »Blog Archive » Hottest in whatever many years
		The report suggests that the famous “hockey stick” temperature curve was based strongly on tree growth patterns of a single group of trees in the western U.S. whose growth is not tied to temperature.
		The NAS report also restores the so-called “Medieval Warm Period” and the subsequent “Little Ice Age” from which the world is currently warming.
		(You won’t read that in the media reports but it is in the report.) Both the MWP and the LIA disappeared with the publication of the UN’s 2001 IPCC report on climate change.
	mitchellconsulting.net /commonsense/?p=1871 (1254 words)

	Terrorist(?) Attacks - antwon.com BBS
		Without them, the IPCC cannot explain why the earth is not warming according to their forecasts, nor can they reasonably claim that global warming will lead to catastrophes of biblical proportions.
		Wallace Broecker, at the Lamont-Doherty Earth Observatory, argues that the MWP and the LIA were indeed global phenomena and 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 interglacial, the Holocene." He reviews several scientific studies that confirm his arguments.
		The MWP was warmer and, according to the seminal work by Hubert H. Lamb, Climate History and the Modern World, civilization thrived under the warmer climate.
	www.antwon.com /scripts/ubbcgi/ubb/Forum2/HTML/000093-2.html (4809 words)

	Global Warming: Real or not? - Page 15 - Bad Astronomy and Universe Today Forum (Site not responding. Last check: 2007-10-10)
		I find it always amazing how you do believe in every temperature reading supporting your position (the little Ice Age, the small cooling in the forties and early fifties), even though they are based on the same techniques as the ones that conclude that overall, on average, the temperature is rising.
		the 500 year baffin report, your third overall, is immediately contradicted by using the same data in the 1250 year baffin report by j.j.
		They use that report to show that tree ring proxies don't show warming, and thus may show that the other ones (that do show warming) are caused by urbanisation.
	www.bautforum.com /showthread.php?p=621426 (4790 words)

	Deltoid: More on Inhofe's war on science
		Also, the IPCC is a scientific organisation of about 2500 scientists, the largest peer-reviewed study ever performed, and all IPCC scientists have concluded that global warming is occurring and that it is primarily the result of human activities.
		Galileo resembles the IPCC and other scientists who have found that climate change is occurring and are being irrationally criticised by the establishment who are trying to keep the status quo so they can continue to profit from fossil fuel extraction and mining activities.
		To sum up: if the historical record says there was a MWP in Europe and the proxies disagree, go with the historical record; if the historical record says there was no MWP in China and the proxies disagree, go with the proxies.
	scienceblogs.com /deltoid/2006/07/more_on_inhofes_war_on_science.php (7631 words)

	The Emperor’s New Climate: Is Global Warming Real?
		Think how many times you hesitate – given the accuracy of weather reports – over whether to bring an umbrella to work, and you have some idea of how hard it might be to project what the average global temperature will be 50 years from now.
		Nevertheless, the summary of each IPCC report got a little bolder, saying in the Third Assessment in 2001, “There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.”
		The IPCC’s Sir John Houghton was photographed for the press in front of the chart.
	www.tysknews.com /Depts/Environment/new_climate.htm (4470 words)

	bound by gravity: The Medieval Warm Period
		There are scientists who disagree, just as there are scientists who do not believe that AIDS is caused by the HIV virus, or who believe in the literal truth of the Bible, or who believe in UFOs.
		But according to John Houghton, co-chair of the IPCC, no more than ten of at least 3000 international climate scientists reject the idea that greenhouse gas emissions are causing the planet to warm.
		It has been noted that most paleoclimatologists developing regionally specific climate reconstructions of past centuries conventionally label their coldest interval as "LIA" and their warmest interval as the "MWP".[5][6] Others follow the convention and when a significant climate event is found in the "LIA" or "MWP" time frames, associate their events to the period.
	www.boundbygravity.com /archives/2005/08/the_medieval_warm_period.php (3553 words)

	UN Erases Medieval Warm Period (Site not responding. Last check: 2007-10-10)
		Third, the statement of the IPCC report itself is that temperatures before 1400 cannot be reliably estimated; this is echoed by the National Academy of Sciences report addressing the Mann et al.
		There is clearly a difficulty that the MWP and the LIA appeared to be regionally intensified in Europe, probably due to ocean circulation variability.
		The other player, especially for the LIA, is reduced solar output during the Maunder Minimum (the most famous) and two other shorter sunspot number minima.
	freerepublic.com /focus/f-news/1735514/posts (2785 words)

	Green Car Congress: June 2006
		The report details, by automaker and vehicle type, the greenhouse gas contributions from the auto sector.
		The report examines the three factors behind greenhouse gas emissions from automobiles: amount of driving, fuel economy, and the carbon content of motor fuel.
		The Detroit Free Press reports that an internal e-mail sent from Ford Motor Co. chairman and CEO Bill Ford to employees backs off of his pledge last year that the company would build 250,000 hybrids a year by 2010.
	www.greencarcongress.com /2006/06 (11015 words)

	Junkscience.com -- Archives, July 2005
		Reporting is scrupulously fair and balanced, editorials are pondered and written using the exquisite tact and careful attention to facts for which the medium is famed and, in complete and total contrast to blogs, vague and general assertions are never used to support pre-existing prejudices." (Tim Worstall, TCS)
		Her first move, reported in The Times is to increase her staff by another 50 to 350.
		That report was so far out in its predictions concerning global warming that simple common sense should dismiss it.
	www.junkscience.com /july05.htm (16253 words)

	jfleck at inkstain » Blog Archive » Listening to the Economists
		The inclusive nature of the Intergovernmental Panel on Climate Change (IPCC), which is currently preparing its fourth assessment of global warming for publication late next year, has further encouraged economists and climate scientists to work together.
		The ‘Special Report on Emissions Scenarios’ that will accompany the assessment was developed in the late 1990s and rests on a number of assumptions that many economists view as outdated or simplistic.
		Follow the drop in temperature from the peak of the MWP to the valley of the LIA.
	www.inkstain.net /fleck/?p=1338 (4604 words)

	Crisis Magazine
		American policy and American factories, power plants, and cars are largely to blame, according to UN scientists, because it’s disproportionately their exhaust that’s putting carbon dioxide (CO2) into the air, causing the planet to heat up.
		It is not only the arcane techniques of paleoclimatology, such as testing core samples of glacial ice for radioisotopes, that testify to the MWP, but history—such as people’s contemporary accounts of what they grew in their fields.
		A funny thing happened as James Hansen was fielding questions from reporters in Washington, D.C., in 1988, terrifying senators with global warming predictions: The forests of eastern North America—no doubt including the Blue Ridge Mountains 60 miles to the west of the capital—were quietly absorbing CO2.
	www.crisismagazine.com /february2004/feature1.htm (4487 words)

	Errors in IPCC climate science » Blog Archive » Little net change in Arctic sea ice extent in 110 years ?
		A longer report was issued in June, 2005, and I have not published comments on that report, but I was pleased to see that more detail and many additional references had been added.
		This makes perfect sense since the hockey stick is a study of climate averaged across the entire northern hemisphere and is of limited use in looking at climate in a single region; the discussion makes that very clear.
		If you’re going to quote large sections of a report, then the first thing you should do is check that the studies cited actually bear the weight of the conclusions.
	www.warwickhughes.com /blog/?p=20 (6611 words)

	Jennifer Marohasy: Peer Review Process at IPCC Formally Questioned
		We understand that Dr. Michael Mann, the lead author of the studies in question, was also a lead author of the IPCC chapter that assessed and reported this very same work, and that two co-authors of the studies were also contributing authors to the same chapter.
		Given the prominence these studies were accorded in the IPCC TAR, we seek to learn more about the facts and circumstances that led to acceptance and prominent use of this work in the IPCC TAR and to understand what this controversy indicates about the data quality of key IPCC studies.
		Posted by: Ender at June 26, 2005 10:17 PM It is not just the letter to the Chairman of the IPCC but the letters to Mann,Bradly and Hughes are also very interesting, and should set the cat amongst the pidgeons.Long overdue.
	www.jennifermarohasy.com /blog/archives/000692.html (2878 words)

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