Global Warming Skeptics Summary

[Hogeye]

Here's a pretty good summary and categorization of global warming apocalypse skeptics' points from this science blog:

I Warming may not actually be occurring. Most respondents seemed to agree that the global average temperature is rising, but some did not. Their doubts hinged mostly on the reliability of temperature and CO2 reconstructions.

A This past winter was so cold. Where's the warming?
B The hockey-stick graph, which suggests the present warming trend is historically anomalous, is flawed. One respondent said it "has been proven false by many papers." Others worried that, at least, it downplays the natural variability in climate.
C The ice core data, one of the ways used to reconstruct past climate conditions, are dubious. They may not represent the global paleoclimate because they sample only a few locations; they appear to contradict the paleobotanic (leaf stomata) data; and they cannot be meaningfully compared with modern surface temperature readings, because they are distinct data sets.
D Ground temperature readings are subject to systematic errors such as the urban heat island effect. One respondent went further and complained that the Climatic Research Unit raw temperature data are "kept under wraps," so outside observers cannot verify that selection effects were properly accounted for.
E Ground temperature readings contradict satellite measurements.
F Reports of changes in polar climate are anecdotal and could be localized effects.

II The present warming could be a natural uptick. Respondents pointed out that climate conditions fluctuate because of volcanism, the obliquity cycle, changes in solar output, and internal (chaotic) variability. Why, they asked, do climate scientists attribute all pre-industrial fluctuations to such natural causes and all industrial-age ones to anthropogenic ones? One respondent put it this way: "Every time I read that we have had 'the hottest summer in 100 years' I wonder what caused that hot summer 100 years ago."

A It could be a rebound from the Little Ice Age or indeed the last Pleistocene glaciation.
B It correlates "nearly perfectly" with solar output.
C It could be explained by variations in cloud cover, which alter how much sunlight the planet absorbs. The cloud cover could, in turn, be explained by variations in cosmic ray flux, modulated by solar magnetic cycles.
D It could be explained by decreases in Earth's magnetic field strength.
E It could be explained by natural methane sources, ranging from termites to the recently discovered aerobic processes in plants.
F It could be partly anthropogenic, but the natural variability is larger. A number of respondents argued that it is hubris to suggest that humanity could have such a large effect on the planet. "Many people seem to have a very exaggerated view of how significant we---and our activities---are," one wrote.

III CO2 emissions cannot explain the warming. This is complementary to the previous item on natural causes, but I broke it out because respondents offered such a variety of hypotheses for why CO2 cannot cause warming.

A Negative feedbacks stabilize the climate system against the direct effect of added CO2. One respondent wrote: "The Earth's ecosystem is far too robust to be affected by this minor change [in CO2 levels over the past century]."
B If CO2 drove climate, changes in gas levels should be followed by changes in temperature. Yet paleoclimate data show the opposite: temperature changes first, then the gas levels.
C In modern times, temperature and CO2 have been only weakly correlated. For instance, there have been long periods of declining temperatures even as CO2 levels have risen. Climate scientists attribute this to masking by aerosol cooling, but their explanation struck many respondents as ad hoc. Also, most human emissions came after 1950, yet the rise in temperature started earlier.
D High CO2 levels earlier in geologic history (for example, during the late Ordovician) did not correlate with high temperatures.
E CO2 is a pittance compared to water vapor. By one estimate, it can cause only 0.2% to 0.3% of the warming.
F The greenhouse effect has "saturated"---further CO2 input does not increase it.
G No one has done lab experiments to study CO2 absorption.
H If CO2 causes warming, then the warmed air should rise, reducing air pressure at the surface. That is not observed. The correspondent who raised this objection cited Marcel Leroux's "Mobile Polar Highs" theory.
I Although CO2 may be a factor, rising levels of this gas are due not to emissions but to reduced uptake by the oceans (perhaps caused by a diminished phytoplankton population).

IV Climate models are unconvincing. In this category, I put the argument that, whatever the inherent plausibility of anthropogenic global warming, climate scientists have yet to present a solid case. The concerns here revolve around the inability of models to capture the complexity of the climate system.

A The correlation of CO2 levels with temperature is not causation.
B Weather forecasting is so unreliable. How could long-term climate forecasting be any better?
C The range of model predictions is wide, casting doubt on their reliability.
D Models can't even predict El Nino.
E Models can't even explain past data. One respondent wrote: "Claiming the models can predict climate is either wishful thinking, ignorance or deceit." Others were more circumspect. One of the few respondents to say what could change their minds wrote: "I'd like to see environmental data from the 1970s fed into today's climate models and the 'predictions' match what actually happened." Another asked whether models can explain climate over geologic time.
F Models are not proof. They can be used to prove anything. Being non-falsifiable, they are not really science.
G The burden of proof rests with those claiming anthropogenic warming. Because mitigating climate change would entail huge costs, and because past warming episodes have been natural, it is up to climate scientists to dispel all reasonable doubts---not to climate skeptics to prove them wrong.

V Warming is a good thing, so we shouldn't try to stop it. The arguments here varied from specific benefits of warming to general reassurances that Earth and its inhabitants have done just fine in earlier periods of warming.

A It will increase humidity in tropical deserts and improve the lot of high-latitude regions.
B Higher CO2 levels encourage plant growth, and that's good.
C Sea level will rise gradually enough that we can readily adapt. The example the respondent gave was beachfront property. Its value will gradually decline as sea levels gradually rise, encouraging a move farther inland over the usual cycle of property investment.
D Historically, humanity has done better during periods of warmer climate.
E For most of its history, Earth has been warmer than today. The idea is that global warming is nothing to fear because it merely takes us back to a more natural set of conditions. Animals and plants seemed to do just fine in those periods of warm climate. One respondent wrote: "Our present chilly climate is the aberration when judged on a geological time scale." Over geologic time, the global mean temperature is 22 degrees C, versus today's 15.5 degrees C.
F It staves off the next glaciation, which we're due for.
G Claims that global warming has worsened storm damage, or will do so, are overblown. If storm damage seems to have increased, it is simply because more people live in storm-prone regions and their plight is more widely publicized than before.
H Attempts to stop global warming would do more damage they than avert. Warming might be bad, but it is better than the alternative, be it Kyoto or some other mitigation strategy. The underlying assumption here is that the null strategy---letting the economy adopt non-carbon energy sources as commodity prices dictate, without any explicit reference to global warming---carries the least costs.

VI Kyoto is useless, or worse. Many of the complaints were specific to the Kyoto Protocol, which sets up a cap-and-trade system for greenhouse gases.

A It would bankrupt us. One correspondent said Kyoto mandates "a practically unlimited expenditure of effort (and money, naturally)."
B Even it would not bankrupt us per se, it would divert resources from other, better-established priorities.
C It would reduce warming by a meager 0.02 degrees C.
D It exempts developing countries, whose emissions intensity and growth rates are much higher than those of developed countries.
E People may claim to support it, but their energy-wasting habits belie their true sentiments.

VII People who argue that human activity causes global warming can't be trusted. Now we get to what seems to be the single biggest complaint: doubts as to the competence or motivation of scientists and others who accept anthropogenic climate change. Many respondents perceive scientists as jumping to conclusions, haughtily dismissing doubters, refusing to take the time to explain things, and adopting absolutist positions. One respondent wrote: "What data would convince me? I don't know if data is the problem as much as needing to perceive an objective voice." Cataloging these complaints has been hard, but here is my attempt.

A Climate scientists have lost their credibility by making bad calls.

1 They used to predict an imminent ice age.
2 They falsely attributed the ozone hole to CFCs. The respondent who raised this point wrote that the ozone hole was clearly not due to CFCs because it began to recede before CFCs were phased out.
3 They uncritically accepted the hockey-stick graph, which was clearly "fraudulent" from the start.
4 They are guilty of doomsaying, which has been so consistently wrong in the past.
5 They were too quick to connect last year's hurricane season with global warming.

B Climate scientists behave unscientifically.

1 They ignore contrary data and alternative explanations. Respondents complained that climate scientists are guilty of groupthink. For them to admit they might be wrong would hurt their reputation and funding chances, so they tend to cling to positions with a fervor that the data do not justify. The IPCC was said to seek out evidence that supports its preconceived conclusion. Similarly, people complained that scientific journals do not publish contrary data, presumably because of negative peer reviews by dogmatic climate scientists.
2 They are arrogant. Researchers, wrote one respondent, "go ballistic if anyone voices doubt." Another said: "A person with doubts, or simply unanswered questions, is shut out of the debate. One can only ask questions when it is phrased with unwavering support for warming."
3 They have let themselves get caught up in activists' agendas.
4 They themselves have an activist agenda. Respondents were suspicious that global climate change fits a little too conveniently into a certain environmentalist narrative that holds that humans can do no good (least of all if those humans are Republicans). Moreover, respondents said that if taken at face value, global warming seems to demand Soviet-style government action, which is problematic in its own right and a sign that the hypothesis is ideologically motivated. Because the U.S. is often singled out for its policies, there is a whiff of anti-Americanism, too.
5 They have a financial interest in global warming. Now we're starting to get into more serious accusations that scientists push global warming because it helps them curry favor with granting agencies. One person wrote: "There are no grants available to disprove global warming.... [Researchers] gather at government's teats for monetary nourishment, telling mommy whatever she wants to hear." Kyoto, too, has created vested interests and a strong incentive to "massage data."

C Activists and journalists have gone overboard.

1 Experts do not, in fact, argue that humanity is the main cause of global warming.
2 The media sensationalizes warming. It focuses on worst-case scenarios and presents tenative research as definitive.
3 Scientific American lost its own credibility on the subject when it printed a one-sided critique of Lomborg's book. One respondent claimed that the magazine "threatened legal action to stifle debate" about Lomborg's book.

[Dardedar]

Here's a pretty good summary and categorization of global warming apocalypse skeptics' points from this science blog:
I Warming may not actually be occurring. Most respondents seemed to agree that the global average temperature is rising, but some did not. Their doubts hinged mostly on the reliability of temperature and CO2 reconstructions.

A This past winter was so cold. Where's the warming?

DAR
Really? You would put this forward as a "good" summary? Something you would want to defend? A group you want to be lumped in with? It really is for the most part an embarrassing compiliation. If one was to see a compliation of creationist grievances with evolution I would expect to see a similar abundance of ignorance and simple mistakes.

It's important to understand the context of this experiment and why this fellow, George Musser of Scientific American put it together. From his intro:

"Which brings me to the experiment. In the comments field, explain which aspects of climate change you don't accept (e.g. you might not think Earth is warming at all, you might not think the warming is due to greenhouse gases, you might not think that the gases are produced by humans, or you might not think warming will cause trouble in the future), what exactly has led you to this conclusion, and -- most important -- what it would take to convince you otherwise. Let's get everything out into the open, so that we can have a real discussion. I hope to convince you, but, at the same time, I am open to being convinced myself. If you assume the best of my intentions, I will assume the best of yours."

Then later:

"...I started the whole discussion because I felt communication on an important scientific issue had broken down, and I figure the best way to make sure we've reconnected the wires is to try and summarize what everyone has been saying. That way, you can correct me if I've misunderstood, misclassified, or just plain missed something. Later, I can take a stab at analyzing the comments and answering some of the requests for further reading, and I hope the discussion will continue from there."

LINK

DAR
He is wanting to teach these poor souls who have obviously lost their way. Good for him. He is getting them on record, making sure that he understands their position as correctly as possible, and then he will attempt to show them where they have gotten off track and thus why, in many instances, their conclusions are mistaken.

The first clue that this compliation of Global Warming Skeptics positions is filled with simple mistakes and the most basic of misunderstandings is the howler at I, A, "This past winter was so cold. Where's the warming?"

I look forward to the extensive response that he (and perhaps other scientists) will write explaining these common misunderstandings. That's what 90% of them are from what I have seen. The remaining 10% are interesting and worth pursuing (probably answered somewhere and I haven't seen it yet).

D.

[Doug]

A This past winter was so cold. Where's the warming?

DOUG
Darrel is correct. This is a ridiculous "rebuttal." One can't rebut a claim about averages by simply pointing out that something does not conform to the average.

And incidentally, this past winter was NOT colder than average.

http://www.noaanews.noaa.gov/stories2006/s2591.htm
=====
March 9, 2006 — The 2005-2006 Winter season was the fifth warmest December-February period on record for the contiguous United States, according to scientists at the NOAA National Climatic Data Center in Asheville, N.C. During the same time, drought conditions worsened in the Southwest and southern Plains, while the Northwest endured heavier-than-average precipitation.
========

Do we need to roast your summary point by point, or are you going to check the facts yourself?

[Hogeye]

You would put this forward as a "good" summary? Something you would want to defend?

No, it is simply a good relatively complete list of objections. Some points I would defend, and some are laughable. Here are some I would defend (and in some cases have defended here), some more than others: IB, ID, IE, IIA, IIB, IIF, IIIB, IIIC, IVA, IVF, IVG, VB, VD, VG, VH, (VIB, VIC, i.e. Kyoto is a ridiculously expensive program that would have virtually no effect on temp). Also, a lot of points in VII are true, but ad hom so are irrelevant.

My favorite points are IB (the MWP was significantly warmer than today), IIB (the sunspot theory), and IIIB/IVA (CO2 lags temp change by up to 800 years per another graph I showed; temp rise causes CO2, not the other way around).

[Dardedar]

Do we need to roast your summary point by point, or are you going to check the facts yourself?

DAR
What a tedious job that would be. But it wouldn't take an expert very long at all. I look forward to the FAQ type rebuttal Scientific American will put together for each one of these.

So Hogeye picks out his "favorite" objections he thinks are the most troublesome for the standard view of global warming:

HOGEYE
My favorite points are:

a) IB (the MWP was significantly warmer than today),

b) IIB (the sunspot theory),

c) and IIIB/IVA (CO2 lags temp change by up to 800 years per another graph I showed; temp rise causes CO2, not the other way around)

DAR
If Hogeye was interested in "checking the facts" on these himself, he could have done it long ago. Apparently he finds the standard issue facts unpersuasive. Perhaps he will bring these up at the up coming lecture. Chameides should be able to respond to these with half his brain tied behind his back. I have shared the links responding to these problems many times but unfortunately they were written by experts in climatology, (rather than miners, captains and economists) so Hogeye is especially suspicious.

D.

[Hogeye]

In other words, Darrel could not refute the points, so he resorted to argumentum ad hominem - all statements by "miners, captains and economists" are false. Meanwhile, I've been addressing the actual arguments and claims of his esteemed scientists, often finding them lacking.

[Savonarola]

In other words, Darrel could not refute the points, so he resorted to argumentum ad hominem - all statements by "miners, captains and economists" are false. Meanwhile, I've been addressing the actual arguments and claims of his esteemed scientists, often finding them lacking.

For one so eager to point out logical fallacies, Hogeye seems to keep forgetting argumentum ad verecundiam. The act of pointing out this fallacy is, of course, not a fallacy.

[Dardedar]

In other words, Darrel could not refute the points,...

DAR
Of course I have dealt with these points, especially a, b, repeatedly and in great detail. I gave you an article dealing with c, yesterday. Anyone following this knows this to be true.

HOGEYE
so he resorted to argumentum ad hominem - all statements by "miners, captains and economists" are false.

DAR
Of course I have never, and never would, say that or anything close to it. Oops, don't look now, you made a strawman (again). Course I wouldn't want to make too a big deal out of this, happens all the time.

Meanwhile, I've been addressing the actual arguments and claims of his esteemed scientists, often finding them lacking.

DAR
As to how persuasive you and your sources have been, each will decide for themselves. I certainly have learned a lot about the skeptic position and I find it considerably less tenable than I did before you started defending it and before I examined their positions more closely.

I really am about 50/50 on whether I will attend the skeptic conference in Pasadena which will be all about this topic. I think the editor of Skeptic Mag, Michael Shermer might be a rightwinger so it might even be stacked a little toward the skeptic/warming denier side. I do know that the last issue of Skeptic that had an extensive debate between an environmentalist lefty (the earth is a mess and getting worse) vs. a rightwinger type (the earth is doing great and getting better--Lomberg), the environmentalist got his clock cleaned, bigtime. I'll go with the good arguments where ever they lead and if I thought there was anything to these skeptic warming denier claims I would have no hesitation to jump on the train and go after the deluded fools who have bought into Global warming and the "false" warnings. Instead, I am amazed that anyone could fall for this junk considering the rebuttals are quite straightforward and accessable. Perhaps I will find more cogent persuasive arguments put forward by the skeptic side at Shermer's conference.

D.

[Barbara Fitzpatrick]

What I find telling is that industries who don't want to have to change what they are doing are the ones most loudly supporting the skeptic stand, but the insurance companies - the ones who have to pay for the damage - are solidly behind the concept and are urging preventative changes. American industry has always lobbied to prevent change, especially one that requires upfront capital expenditure, even if it would ultimately be beneficial to the industry. Whether or not there is global warming, America needs desparately to be weaned off the oil tit, but industry is using the global warming "controversy" (even though they are the only one controverting) as an excuse to not do what needs to be done anyway from air and water pollution (i.e., national health) and national security standpoints.

America needs to change it's fuel source. Period. It will take capital expenditure to do it, but in a sense localized capital expenditure - and localized change. Anything wired for electricity will not have to change anything, but the utility companies will have to replace current power plants with solar, wind, and biomass electric generating plants. Diesel engines won't have to change to run biodiesel, but the oil industry will have to change how they produce fuel. The auto industry will have to change engines and fuel tanks to take a variety of fuels and a lot more emphasis needs to be put on EVs and plug-in hybrids, but very little change will need to be made at the consumer end (which is just as well, since the majority of consumers won't/wouldn't change unless they had no choice whatsoever).

About the only other major change - and again, this doesn't overtly effect the majority of Americans - is agribiz. Our subsidized commercial agriculture that is destroying topsoil, polluting air and waterways, and adversely affecting American health (all reasons to change even if global warming isn't true) runs on massively subsized petroleum (American corn is cheap enough even as an import to put local farmers out of business in 3rd world nations because it's double subsidized - farm subsidies and oil subsidies) to the extent that 1 calorie of food energy costs over 10 calories of fuel energy to produce - an energy deficit we've been running for close to 50 years now.

I've been a gardener and I know global warming is true. I believe the science that indicates human/industrial causation because I understand the logic behind it, even if I don't truly understand the science itself. But it wouldn't matter - the changes needed to address the issue of global warming were already needed to address pollution/health and national security issues - and the need escalates with everyday we waste arguing about the validity of global warming as a rationale for making those changes.

[Dardedar]

DAR
An interesting bit on Global Warming, which was written in response to this question:

***
Lyin' Tamer
On global warming
By Umbra Fisk
10 Apr 2006

The many articles on global warming conclude with something about the inherent complexity and uncertainty of the issue. So exactly what is the evidence for (and against) arguing that the current warming trend is inside the scope of normal fluctuations? What is the evidence for (and against) arguing that the trend is caused by human activities, and is not just part of a "natural cycle"? Is it true that the U.S. is just about the only country where scientists seriously debate the reality of global warming? Who are these people writing articles telling us we don't have anything to worry about? What are their credentials?

Answer here

Several links to a large selection of charts. Covers a lot of the same points Chameides did tonight.

[Dardedar]

DAR
More gagging of the science by Bushco:

***

Scientists Say They're Being Gagged by Bush
By Juliet Eilperin
The Washington Post

Sunday 16 April 2006

White House monitors their media contacts.

Washington - Scientists doing climate research for the federal government say the Bush administration has made it hard for them to speak forthrightly to the public about global warming. The result, the researchers say, is a danger that Americans are not getting the full story on how the climate is changing.

Employees and contractors working for the National Oceanic and Atmospheric Administration, along with a U.S. Geological Survey scientist working at an NOAA lab, said in interviews that over the past year administration officials have chastised them for speaking on policy questions; removed references to global warming from their reports, news releases and conference Web sites; investigated news leaks; and sometimes urged them to stop speaking to the media altogether. Their accounts indicate that the ideological battle over climate-change research, which first came to light at NASA, is being fought in other federal science agencies as well.

These scientists - working nationwide in research centers in such places as Princeton, N.J., and Boulder, Colo. - say they are required to clear all media requests with administration officials, something they did not have to do until the summer of 2004. Before then, climate researchers - unlike staff members in the Justice or State departments, which have long-standing policies restricting access to reporters - were relatively free to discuss their findings without strict agency oversight.

"There has been a change in how we're expected to interact with the press," said Pieter Tans, who measures greenhouse gases linked to global warming and has worked at NOAA's Earth System Research Laboratory in Boulder for two decades. He said that although he often "ignores the rules" the administration has instituted, when it comes to his colleagues, "some people feel intimidated - I see that."

Christopher Milly, a hydrologist at the U.S. Geological Survey, said he had problems twice while drafting news releases on scientific papers describing how climate change would affect the nation's water supply.

Once in 2002, Milly said, Interior officials declined to issue a news release on grounds that it would cause "great problems with the department." In November 2005, they agreed to issue a release on a different climate-related paper, Milly said, but "purged key words from the releases, including 'global warming,' 'warming climate' and 'climate change.' ''

...snip...

http://www.truthout.org/docs_2006/041706F.shtml

D.

[Barbara Fitzpatrick]

You'd think the current Administration's "gag rule" on climate science would be the answer to Hogeye's suggestions of a governmental conspiracy creating the global warming "scare". Of course, that would be logical.

[Hogeye]

Barbara, in case you didn't know: government is incompetent. There is no reason whatsoever to expect consistency. Just as the USEmpire once funded both growing tobacco and anti-tobacco propaganda, today the Empire takes both sides of environmental apocalypse issues. The NSF funds all sorts of alarmist climate research - that's a fact. Global warming skeptics can kiss govt funding goodbye.

I attended the lecture by Chameides at the Physics building. He pretty much admitted that greenhouse gasses were not the cause of global warming, but rather a feedback factor to solar/orbital causes. My main criticisms of his talk:

1) When claiming catastrophic global warming, he used only short-range charts of the past 200 years or so. This, of course, hides the fact that the Medieval Warm Period was just as warm (or warmer.)

2) While he did talk about variations due to earth's elliptical orbit, he didn't talk about the sunspot theory at all. He had it on his short list of "causes," but rejected it out of hand, asserting that the change would be too small to account for recent warming. This was rather strange - suddenly he forgot all about feedback mechanisms, even though he had just been discussing them. Apparently when human-caused greenhouse gasses can't explain the magnitude of change, it's okay to look at feedback. But not for sunspot-caused changes!


Instead of rehashing Mann et al's dubious historical climate chart again, let me tell you what I find more convincing. I'm an Occam's razor guy. I trust a temperature history based on a single proxy a hell of a lot more than one with various proxies cobbled together. I find it extremely suspicious that all the "hockey-stick" graphs are of the misc. proxies cobbled together type, but the big MWP graphs are based on a single proxy - be they ice bores, lake sediment layers, or whatever.

[Dardedar]

HOGEYE
He [Chameides] pretty much admitted that greenhouse gasses were not the cause of global warming...

DAR
Is it opposite day? That's a day where you say the opposite of what you mean or what is true. If it is opposite day, no one told me. There should be an announcement or something.

When I went to dinner with Chameides I made a point to give him Hogeye's main three favorite skeptic arguments as outlined above. His responses were detailed, substantive and inline with the ample information Hogeye has already been given ad naseaum. Too bad Hogeye didn't raise his hand and try to ask a question after the lecture.

Also, night before last I watched a movie that finally gives a good substantive scientific rebuttal to Crichton's fictional novel about global warming:


.
.

[Doug]

I attended the lecture by Chameides at the Physics building. He pretty much admitted that greenhouse gasses were not the cause of global warming, but rather a feedback factor to solar/orbital causes.

DOUG
???? No, Darrel, it is not opposite day. It must be Fantasy Island day.

Chameides explained clearly and concisely how we can know that global warming is occurring, and how we can be sure that it is not just a natural cycle but instead is caused by greenhouse gases in the atmosphere.

He did not attribute it to solar/orbital causes. He was quite clear that it was due to humans burning fossil fuels, and he explained how we can know that.

Hogeye wrote:
My main criticisms of his talk:

1) When claiming catastrophic global warming, he used only short-range charts of the past 200 years or so. This, of course, hides the fact that the Medieval Warm Period was just as warm (or warmer.)

DOUG
Bill Chameides is with the Environmental Defense Fund. Their website has this:
See here.

MYTH: The global warming over the past century is not unusual. For example, the Medieval Warm Period (MWP), roughly from A.D. 1000 to 1400, was warmer than the 20th century. Recent global warming is part of a natural cycle.
FACT:Ten independent scientific studies all have found a large 20th-century warming trend compared to temperature changes over the past millennium or two. Uncertainty exists as to exactly how warm the present is compared to the MWP but other studies, using different methods, find no evidence of any period during the last 2,000 years warmer than the 1990s. Humans likely have caused most of the warming over the past 50 years.

Hogeye wrote:

2) While he did talk about variations due to earth's elliptical orbit, he didn't talk about the sunspot theory at all. He had it on his short list of "causes," but rejected it out of hand, asserting that the change would be too small to account for recent warming. This was rather strange - suddenly he forgot all about feedback mechanisms, even though he had just been discussing them. Apparently when human-caused greenhouse gasses can't explain the magnitude of change, it's okay to look at feedback. But not for sunspot-caused changes!

MYTH: The Earth’s warming is caused by natural factors like increased sunlight and sunspots or a decrease in cosmic rays, not by greenhouse gases (GHGs).
FACT:Modeling studies indicate that most of the warming over the past several decades was probably caused by the increase in human-produced GHGs. Climate models cannot account for the observed temperature changes over the past 150 years unless they factor in this increase in GHGs. Most scientists agree that the observed changes in the intensity of sunlight can not, by themselves, account for the large warming that took place over the past 25 years. The purported correlations between the amount of cosmic rays and Earth’s temperature are the result of flawed analytical methods.

Hogeye wrote:

Instead of rehashing Mann et al's dubious historical climate chart again, let me tell you what I find more convincing. I'm an Occam's razor guy. I trust a temperature history based on a single proxy a hell of a lot more than one with various proxies cobbled together. I find it extremely suspicious that all the "hockey-stick" graphs are of the misc. proxies cobbled together type, but the big MWP graphs are based on a single proxy - be they ice bores, lake sediment layers, or whatever.

DOUG
Ice cores, sediment layers, and such sources corroborate each other and help scientists know about the past. They are not "cobbled together" anymore than the sources for evolution or any other study of the past.

MYTH: Human activities contribute only a small fraction of carbon dioxide (CO2) emissions, an amount far too small to have a significant effect on atmospheric greenhouse gas concentration.
FACT:Before the Industrial Revolution, CO2 emitted from large natural sources was balanced by the amount removed through natural processes. Human activities, which since the Industrial Revolution have put twice as much CO2 into the atmosphere as can be readily removed by the oceans and forests, have upset this natural balance. Today’s CO2 levels are the highest in the past 420,000 years. Scientists have shown, through carbon isotope and atmospheric oxygen measurements, that this additional CO2 is from human activities and, in large part, from fossil fuels.

[Barbara Fitzpatrick]

I wish I'd hung on to the article - I saw a science article several months ago indicating newest evidence shows the current CO2 levels are the highest they've been in 600,000 years.

According to my son (when he was taking paramedic coursework), the human need to breathe is triggered, not by a desire for O2, but for the need to get rid of CO2 - but the body can get used to higher CO2 levels in the blood (happens to miners), but if something causes the breathing to stop - there's no "trigger" to start again. Just putting an O2 mask on won't do it, you have to start artificial respiration or they just die. Wonder how much CO2 in the atmosphere it will take for all humans to get to that point?

[Hogeye]

Ice cores, sediment layers, and such sources corroborate each other and help scientists know about the past. They are not "cobbled together" anymore than the sources for evolution or any other study of the past.

In the Mann model, various proxies covering various different time periods are stitched together with rather arbitrary weighting to come up with their preconceived notion of impending apocalypse. Doug, don't you find it the least bit suspicious that almost every proxy taken alone shows a clear MWP, but the doctored amalgamation doesn't?

I've been reading up, and I have another concern not already mentioned: The (well-known undisputed) CO2 fertilization effect makes tree rings useless as a temperature proxy in the 20th century. I.e. The well-documented increase in CO2 accounts for the tree growth in the last century, not a climactic temperature change. Tree-rings as a proxy for temperature have always been dubious, since no one really knows what part of growth is attributable to percipitation (or CO2 levels) rather than temperature. It's not like e.g. the isotopes in ice bores that let us distinguish between percipitation and temperature. Dendachronology started out as a dating tool; it's not surprising that it doesn't work well as a temperature proxy.

Hogeye> I attended the lecture by Chameides at the Physics building. He pretty much admitted that greenhouse gasses were not the cause of global warming, but rather a feedback factor to solar/orbital causes.

Doug> Chameides explained clearly and concisely how we can know that global warming is occurring, and how we can be sure that it is not just a natural cycle but instead is caused by greenhouse gases in the atmosphere.

Right - except for the misleading use of the word "cause." If you mean "cause" as a necessary and sufficient condition then clearly greenhouse gasses are not the cause of global warming. It's simply not a heat source. Chamides explained that the natural solar inputs are amplified by greenhouse gasses. Greenhouse gasses may be a feedback factor resulting in amplification, but not the cause of global warming.


Doug gives a good example of Chameides web page ducking the question of whether the MWP was as warm or warmer than our modern warm period.

MYTH: The global warming over the past century is not unusual. For example, the Medieval Warm Period (MWP), roughly from A.D. 1000 to 1400, was warmer than the 20th century. Recent global warming is part of a natural cycle.

FACT:Ten independent scientific studies all have found a large 20th-century warming trend compared to temperature changes over the past millennium or two. (Avoiding the question by switching to rate of change rather than absolute temp.) Uncertainty exists as to exactly how warm the present is compared to the MWP (admitting they can't show that late 20th century was hotter) but other studies, using different methods, find no evidence of any period during the last 2,000 years warmer than the 1990s. (...But there exist, somewhere, with unspecified soundness, some studies which don't disprove but don't show that the MWP was warmer.) Humans likely have caused most of the warming over the past 50 years. (Convenient but unsupported conclusion.)

Chameides bets 10 studies, I'll raise him six...

As dramatic and important as these observations are, they are not the entire story of Loehle's insightful paper.  His analyses also reveal a long-term linear cooling trend of 0.25°C per thousand years since the peak of the interglacial warm period that occurred some 7000 years ago, which result is essentially identical to the mean value of this trend that was derived from seven prior assessments of its magnitude and five prior climate reconstructions.  In addition, Loehle's analyses reveal the existence of the Medieval Warm Period of 800-1200 AD, which is shown to have been significantly warmer than the portion of the Modern Warm Period we have so far experienced, as well as the existence of the Little Ice Age of 1500-1850 AD, which is shown to have been the coldest period of the entire 3000-year record.

As corroborating evidence for the global nature of these major warm and cold intervals, Loehle cites sixteen peer-reviewed scientific journal articles that document the existence of the Medieval Warm Period in all parts of the world, as well as eighteen other articles that document the worldwide occurrence of the Little Ice Age.  And in one of the more intriguing aspects of his study - of which Loehle makes no mention, however - both the Sargasso Sea and South African temperature records reveal the existence of a major temperature spike that began sometime in the early 1400s.  This abrupt warming pushed temperatures considerably above the peak warmth of the 20th century before falling back to pre-spike levels in the mid 1500s, providing support for the similar finding of higher-than-current temperatures in that time interval by McIntyre and McKitrick (2003) in their reanalysis of the data employed by Mann et al. to create their controversial "hockeystick" temperature history, which gives no indication of the occurrence of this high-temperature regime.

In another accomplishment of note, the models developed by Loehle reveal the existence of three climate cycles previously identified by others.  In his culminating seventh model, for example, there is a 2388-year cycle that he describes as comparing "quite favorably to a cycle variously estimated as 2200, 2300, and 2500 years (Denton and Karlen, 1973; Karlen and Kuylenstierna, 1996; Magny, 1993; Mayewski et al., 1997)." There is also a 490-year cycle that likely "corresponds to a 500-year cycle found previously (e.g. Li et al., 1997; Magny, 1993; Mayewski et al., 1997)" and a 228-year cycle that "approximates the 210-year cycle found by Damon and Jirikowic (1992)."

The compatibility of these findings with those of several studies that have identified similar solar forcing signals caused Loehle to thus conclude that "solar forcing (and/or other natural cycles) is plausibly responsible for some portion of 20th century warming" or, as he indicates in his abstract, maybe even all of it. - Earth's Temperature History: Putting the 20th Century in Proper Perspective

[Dardedar]

HOGEYE
Chameides bets 10 studies, I'll raise him six...

DAR
You don't raise anything. You quote a dedicated skeptic site which claims:

As corroborating evidence for the global nature of these major warm and cold intervals, Loehle cites sixteen peer-reviewed scientific journal articles that document the existence of the Medieval Warm Period in all parts of the world, as well as eighteen other articles that document the worldwide occurrence of the Little Ice Age.

DAR
But no reference provided whatsoever for this claim, unlike the ten actually provided (by me) for Chameides ten. They didn't even give Loehle's whole name.

And no one doubts a MWP anyway so such a claim is vapid without more definition.

D.
-------------------------
"Dr. Craig Loehle is the developer of Global Optimization a Mathematica application package that has been on the market since 1998. He is the founder and president of Loehle Enterprises, which develops and markets software and also offers consulting. Dr. Loehle has been offering consulting services since 1993 to a wide range of clients.

Dr. Loehle received his Ph.D. in mathematical ecology in 1982 from Colorado State University. He has published over one hundred papers in applied mathematics and ecology on topics that include statistical models, optimization, simulation, artificial intelligence, fractals, and wavelets. His popular book on creativity, Thinking Strategically, is available from Cambridge University Press."

[Doug]

Chameides bets 10 studies, I'll raise him six...

In addition, Loehle's analyses reveal the existence of the Medieval Warm Period of 800-1200 AD, which is shown to have been significantly warmer than the portion of the Modern Warm Period we have so far experienced, as well as the existence of the Little Ice Age of 1500-1850 AD, which is shown to have been the coldest period of the entire 3000-year record.

DOUG
As Darrel has pointed out, your research is insufficiently documented. In addition, Chameides does not deny the MWP.

Address his best evidence instead of ducking the question. Chameides explained that if the increased CO2 levels were simply due to natural causes, the amount of oxygen in the atmosphere would remain the same. But it has not remained the same. It has decreased. It has decreased along with the rise of CO2, showing that it is the burning of fossil fuel that increases CO2 AND reduces the amount of oxygen.

So we KNOW that the increase in greenhouse gases is caused by humans.

Hogeye, you need to read this.


It includes this:

Recovery from the Little Ice Age: Skeptics have claimed that the warming over the 20th century is simply a natural recovery from the Little Ice Age (roughly A.D. 1600–1850), a cool period caused by changes in natural forces. The facts are similar to what we have discussed above: Climate studies have taken into account all the major forces that can change the climate, and have shown that the warming over the second half of the 20th century can be explained only if GHGs are included.While changes in sunlight and volcanic activity can possibly explain the transition into the
Little Ice Age, they cannot fully explain the warming since the end of the Little Ice Age.

DOUG
Regarding the Medieval Warming Period, you are still misunderstanding the issue. Little Ice Ages and Medieval Warming Periods are not the issue here.

MYTH: The global warming over the past century is nothing unusual. For example, the Medieval Warm Period (MWP), roughly from A.D. 1000 to 1400, was warmer than the 20th century. This indicates the global warming we are experiencing now is part of a natural cycle.
FACT: Ten independent scientific studies all have found a large 20th-century warming trend compared to temperature changes over the past millennium or two. Uncertainty exists as to exactly how warm the present is compared to the MWP. Some studies have received valid criticism for possibly underestimating the magnitude of longer-lasting, century-scale temperature changes, such as the warming during the MWP. However, other studies, using different methods, still find no evidence of any period during the last 2,000 years that was warmer than the 1990s. Most importantly, any uncertainty about whether the present is warmer than the
MWP has little effect on the finding that humans likely have caused most of the warming over the past 50 years. A separate body of studies has provided the main evidence for this finding. (See the Myth on causes of warming.)

[Dardedar]

DAR
This just in. Oh, and smoking causes cancer too....

***
Federal Study Finds Accord on Warming

By Andrew C. Revkin
The New York Times

Wednesday 03 May 2006

A scientific study commissioned by the Bush administration concluded yesterday that the lower atmosphere was indeed growing warmer and that there was "clear evidence of human influences on the climate system."

The finding eliminates a significant area of uncertainty in the debate over global warming, one that the administration has long cited as a rationale for proceeding cautiously on what it says would be costly limits on emissions of heat-trapping gases.

But White House officials noted that this was just the first of 21 assessments planned by the federal Climate Change Science Program, which was created by the administration in 2002 to address what it called unresolved questions. The officials said that while the new finding was important, the administration's policy remained focused on studying the remaining questions and using voluntary means to slow the growth in emissions of heat-trapping gases like carbon dioxide.

The focus of the new federal study was conflicting records of atmospheric temperature trends.

For more than a decade, scientists using different methods had come up with differing rates of warming at Earth's surface and in the midsection of the atmosphere, called the troposphere. These disparities had been cited by a small group of scientists, and by the administration and its allies, to question a growing consensus among climatologists that warming from heat-trapping gases could dangerously heat Earth.

The new study found that "there is no longer a discrepancy in the rate of global average temperature increase for the surface compared with higher levels in the atmosphere," in the words of a news release issued by the Commerce Department and approved by the White House. The report was published yesterday online at climatescience.gov.

The report's authors all agreed that their review of the data showed that the atmosphere was, in fact, warming in ways that generally meshed with computer simulations. The study said that the only factor that could explain the measured warming of Earth's average temperature over the last 50 years was the buildup heat-trapping gases, which are mainly emitted by burning coal and oil.

All other industrial powers except Australia have accepted mandatory restrictions on such gases under the Kyoto Protocol, but efforts to extend and expand that treaty face hurdles.

The Intergovernmental Panel on Climate Change, a United Nations body that conducts an exhaustive periodic review of causes and impacts of warming, has just finished reviewing drafts of its next assessment, to be published next year.

Scientists involved in that effort, while refusing to comment on specific findings, said that research since the last assessment, in 2001, had generated much greater certainty that humans are the main force behind recent warming, and that much more warming is in store unless emissions are curtailed.

Michele St. Martin, a spokeswoman for the White House Council on Environmental Quality, said, "We welcome today's report" and added that it showed that President Bush's decision to focus nearly $2 billion a year on climate monitoring and research was "working."

Thomas Karl, the director of the National Climatic Data Center in the Commerce Department and the lead editor of the report, said it was not simply a review of existing work but also, by forcing scientists with differing views to meet repeatedly, resulted in breakthroughs.

"The evidence continues to support a substantial human impact on global temperature increases," Dr. Karl said.

John R. Christy, an author of the new report whose analysis of satellite temperature records long showed little warming above Earth's surface, said he endorsed the conclusion that "part of what has happened over the last 50 years has clearly been caused by humans."

But Dr. Christy, who teaches at the University of Alabama, Huntsville, said the report also noted that computer simulations of the climate system, while good at replicating the globally averaged temperature changes, still strayed in projecting details, particularly in the tropics.

This implied that the models remained laden with uncertainties when used to study future trends, he said.

Dr. Christy also said that even given what the models projected, it would be impossible to slow warming noticeably in the coming decades. Countries would be wise to seek ways to adapt to warming, he added, even as they seek new sources of energy that do not emit heat-trapping gases.

http://www.truthout.org/issues_06/050306EA.shtml

***

DAR
Did I mention that smoking causes cancer? Is that okay to point out or is that a misleading use of the word "cause"?