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Henrik Svensmark is one of the main proponents of the theory that cosmic rays have an impact on climate. Following is a quote from an article by Henrik Svensmark written in May 2000:

The influence of solar variability on climate is currently uncertain. Recent observations have indicated a possible mechanism via the influence of solar modulated cosmic rays on global cloud cover. Surprisingly the influence of solar variability is strongest in low clouds (less than or equal to 3 km), which points to a microphysical mechanism involving aerosol formation that is enhanced by ionization due to cosmic rays. If confirmed it suggests that the average state of the heliosphere is important for climate on Earth.

Citation: Marsh, N. G. and H. Svensmark. "Low Cloud Properties Influenced by Cosmic Rays". Physical Review Letters. 85, 4 (2000).

His ideas involve cosmic ray influence on LOW CLOUDS. In that case, under the theory, fewer cosmic rays imply fewer low clouds, which would imply a warmer climate. This idea has significant weaknesses which are covered here for example. One of the main problems with this idea is that cosmic rays have, since 1985 trended in the opposite direction necessary to explain the warming.

Now you seem to be suggesting that someone has reversed the theory, and now say that cosmic rays influence HIGH CLOUDS?!! Who exactly has made this postulate? Where are your citations? What are the reasons for the switch? Without such information, I have to strongly suspect that what you say comes straight from an oil industry funded PR firm that is responding to growing public knowledge about the science.

"cosmic rays being a major influence on low level cloud formation"

The problem with the cosmic ray theory is that there has not been any increase in cosmic rays over the 30 odd years we have been observing them. In other words how can no change in cosmic rays cause a change in cloud cover?

The implicit assumption of "skeptics" (and I used the term lightly) is that the IPCC has not investigated solar flux. The IPCC attribution graph shows this assumption is false, in fact it shows that the IPCC belives the sun is responsible for roughly a quarter of the warming and humans for more than half.

Citing habitual liar George Will somewhat diminishes your otherwise compellingly counterfactual argument.

Wow, can I call it or what? :) No, that's wrong also.

How do you explain the cooling trend in the 70s? You guys are the same tossers who were out there in the 70s claiming the Ice Age was coming,

Not really.

the same alarmists who were warning that everyone would soon burn up because of the ozone hole (which is now smaller, but the hole has always been there) in the 80s

Not really.

But, hey:

Don't try to educate me on the science

Finding the sand comfortable around your head, eh?

How do you explain the cooling trend in the 70s? You guys are the same tossers who were out there in the 70s claiming the Ice Age was coming,

Not really.

the same alarmists who were warning that everyone would soon burn up because of the ozone hole (which is now smaller, but the hole has always been there) in the 80s

Not really.

But, hey:

Don't try to educate me on the science

Finding the sand comfortable around your head, eh?

How do you explain the cooling trend in the 70s? You guys are the same tossers who were out there in the 70s claiming the Ice Age was coming,

Not really.

the same alarmists who were warning that everyone would soon burn up because of the ozone hole (which is now smaller, but the hole has always been there) in the 80s

Not really.

But, hey:

Don't try to educate me on the science

Finding the sand comfortable around your head, eh?

How do you explain the cooling trend in the 70s? You guys are the same tossers who were out there in the 70s claiming the Ice Age was coming,

Not really.

the same alarmists who were warning that everyone would soon burn up because of the ozone hole (which is now smaller, but the hole has always been there) in the 80s

Not really.

But, hey:

Don't try to educate me on the science

Finding the sand comfortable around your head, eh?

You're right. All of the world's climate scientists are idiots, and didn't figure out this obvious thing which you did. Right? Because that's the implications of what you're saying: you think essentially all of the world's climate scientists are complete and utter idiots.

Of course, what you said is completely untrue, but hey, who cares? Like most anti-global warming arguments, they sound good to someone who knows absolutely nothing about the subject.

Talk to some IPCC contributors, or at least start your mythbusting here. Not convinced...look in the appendix of the IPCC reports and check out the reseach by all the contributors, that by design represent the considered scientific opinion of most of the national scientific bodies on the planet.

Sure we have spent billions in the last decade confirming the science but why does the US still find itself isolated at Bali? We now know (in gigatons/yr roughly what has to be done by when), the first time I heard the target of 450ppm was from Lord Oxbourough when he was chairman of Shell. The negotiators have squezeed enougn for "national intrest" already, time to face reality and accept the need for targets that the rest of the world have already basically agreed on.

Before you get on your high horse and start saying it's just a theory, or a conspiracy by envirofascists or something, how about learning a bit about what we do know, what we don't know, and the degrees of uncertainty to each. Great. You now have what we call an "informed opinion"... and as such you recognise that you didn't actually have a clue what you were talking about when you posted that comment.

I don't want to get bogged down in an argument about Al Gore's (alleged) political hypocricy, nor do I care if you trust him, or for that matter me either. What I and am saying is that his movie was (at the time of release), a faithfull representation of the IPCC reports. I am not the only one who claims this, the IPCC scientists who wrote the reports reviewed the movie. follow the "original assesment" link in this otherwise interesting story.

"I interpreted "the problem" to be green house gases/CO2 not other environmental damage."

That's the diffrence between reductionist science and engineering, right there in that sentance. The "environment" is the system thats stops us all from looking like the poor bastards in Sudan, "capitalisim" and "environmentalisim" are not seperate things...stay with me here ... I assure you I am not a raving hippie and I do hold a BSc in computer science with a major in operations research. "Systems" have been my bread and butter for 20yrs and prior to that I had 15 years of low paid work on sawmills, fishing trawlers, farms, building sites, and several depressing factories.

The "problem" is that the industrial revolution is making our one and only biosphere unsuitable for civilization at such a rate that system will crash in a catastrophic manner rather than a "gracefull" degredation that can be adapted to with ease, humans (as opposed to life) can't reboot from a blue globe of death. Some of the major symptoms of this impending system crash are know by the following reductionist soundbites (in rough order of importance)...

Sixth great extinction.(#0 - The "problem" in a nutshell)
Climate change. (#1 - For it's observable impact on our agriculture)
Collapsed fisheries. (#2 - No grain OR seafood)
Peak oil. (#3 - The global economy fighting itself.)
Deforestation. (#4 - Way too fast for anything to adapt.)
Desertification. (#5 - A symptom of #1 & #4.)
Oil wars. (#6 - A symptom of #3)

I don't hold out a lot of hope for human nature either.

"I don't understand that at all."

That's why the tradgedy of the commons is ...well... a tragedy. Exluding the noble nations, pollution and non-renewable depletion do not factor as costs of doing bussiness, google for texaco and bolivia, BHP and Papua, Shell and Nigeria and just about anything that happens in Asia. The tragedy of the commons is - the - major bug in our current version of capitalist system.

"In a democratic sense everybody has the same right to emit CO2....everybody should get a particular fraction thereof and if they choose to sell it great."

Still reading? - I agree with you and I think the majority of mankind are on our side.

That would lead to increased costs for everything as the "noble" class who purchased up tons and tons of indulgences resell them to actual businesses that create products.

So (in a capitialist sense) how is that different to any other service side industry, eg: a bank loan? The English civil war, the French revolution and the war of independece were all reactions to the excesses of nobility - on a modern global scale we are "the nobility". At the end of the day no amount of politics will change a physical limit of nature, politicians generally refuse to acknowledge any kind of limit that they themselves have not set. If they set that limit according to GDP then the "buying of indulgences" is meaningless because the indulgences are as limitless as GDP.

If our leaders suddenly started using logic, then the difficult part of a demoractic cap and trade scheme is how to credit everyones individual "C02 account" when a large chunk of the population have never seen a letter box. The pra

"See the novel State of Fear...it's not too far off it seems..."

An anti-science fiction writer advising the US senate on climate science, what could possibly go wrong?

"Okay, so they've apparently voted again based on how much consensus there is in their opinion."

That is what is mean by the term "republic of science".

"Still no reference to any science."

That is because you are looking at the Summary for Policy Makers (SPM), the 2007 report is in three parts one unfinished, the other not yet on the web) - the science is in the technical report. But since you went to a bit of trouble writing that post I will do likewise - here is the pdf version of the SPM.

The SPM is intendend to summarize the science so politicians can make informed decisions, ie: The SPM is a peer-reviewed paper that is not cluttered with all that formal refrence notation. To track down the references got end of the glossary (p954) and you will find some references for the glossary itself (ie: they have defined their terms), on the next page is the start of a rather impressive list of contributors (ie: the authors) - the science is here - the contributors are people like Jim Hanssen who's published papers are relatively easy to find, some contributors have banded together here and will often answer specific questions ( such as the math and experiments you are looking for ). Finally on page 967 is the list of reviewers, who's credentials and publications are also "easy" to look up.

I'm sure if you dug around further you would find the workshop notes for the SPM's "working group" but that's where my patience runs out. I'm INAClimatologist but I do I have a "traditional" BSc in computer science with a major in operations research so I can understand (and argue for) the techniques used in building the models. It would be nice if we could just suck in any old subject but the truth is we can't so I (personally) choose to bow to the republic at this point and follow the high level arguments.

I have had an intrest in this since the early 80's when I worked on an old growth sawmill (greenies chained to dozers, ect), wasn't convinced that it "mattered" (even if it were true) until the 2001 IPCC reports, wasn't "alarmed" until the last few years when I realised it's not about wet feet, it's about dustbowls and famine. Not by itself mind you but combined with over fishing, peak oil, ect.

Fixing these problems would be a boom to both the economy and tecnology if nations could agree to some basic rationing of the "commons" based on our "best guess" as to what the biosphere can cope with, for C02 that figure is around 2.5GT/yr and IIRC we are currently 7.5GT over the limit.

There are plenty of studies showing that the global warming issue is caused by the sun getting hotter (look it up...I'll wait), and a recent study showing that the ozone holes at the north pole are getting smaller (did we do that? doubtful. Can a blogger get that kind of reaction, unlikely)

"I have a hard time recommending his film An Inconvenient Truth due to his factual errors and exaggerated claims." (My Emph.)

They are not HIS claims thay are the IPCC's claims, he got the (well deserved) award for communicating those claims to the public. None of the claims are exaggerated rather there is a tendency for critics and shills to highligh his presentations of the worst "business as usual" senario in a range of senarios. I don't expect anyone to listen to a random /. post, so here is a link to what some well known IPCC contributors and climatologists thought of the movie.

Note that the recent well publicised "Artic ice melt" has far exceeded the worst of the senarios predicted by both the 97 & 2007 IPCC reports, even "alarmists" underestimated that one by ~30yrs. Recent observation here in Australia also seem to show an "exaggeragion" over IPCC predictions. The IPCC report represents established science and it's 2007 predictions for Australia and the Artic are starting to look very conservative, OTOH: 1-2 years is not a trend.

I'd suggest http://www.realclimate.org/ as a place where you could start getting informed.

As there are other cycles that do not involve the Cl2O2 molecule but cause similar dramatic ozone depletion, such as cycles including both ClO and BrO (its bromine-containing analogue), any revision to current understanding would most likely simply shift the relative importance of the various ozone-destroying cycles.

As there are other cycles that do not involve the Cl2O2 molecule but cause similar dramatic ozone depletion, such as cycles including both ClO and BrO (its bromine-containing analogue), any revision to current understanding would most likely simply shift the relative importance of the various ozone-destroying cycles.

Bah! Formatting was up the creek. Climatology site

This "lag" is well understood.

Do you really think it is paranoia Ashlie?

Yes, yes I do. I made a lot of posts on a topic that I care about and know a bit about. That they might be disproportionately directed to you could be because you meet the criteria of being (a) wrong about quite a bit, but (b) not loony wrong. (I tend not to waste my time with true crazies.)

But since I would have to Google for "global warming y2k bug" to find the articles, I will just leave it up to you to do so.

Canadian and amateur climate researcher Stephen McIntyre discovered that NASA made a technical error in standardizing the weather air temperature data post-2000. These temperature mistakes were only for the U.S.; their net effect was to lower the average temperature reading from 2000-2006 by 0.15C.

Or do you mean since many left wing think tanks decided they could push their rejected agendas by placing fear into the lives or people based around something that without errors would never have been plausible in the first place.

And if you think Fox news is right wing, then I guess you are more left then I originally thought.Fox news isn't right wing. The shows they have might be but the station, news, and channel itself isn't. But how would you know that, your probably just parroting what other agenda pushing liberals have told you.

In the US, we still don't have corrected numbers...

As many people know, cycles in earth often take longer then 40 years.

Yes - appreciable in the sense of "measurable"; whether you think the present rise (about 20cm in the last century) is significant depends on how bad a 200 year storm-surge / flood event would be where you live. I've seen a picture of the London Embankment (along the Thames) at a spring low tide, showing where the original early Victorian wall came to, and the subsequent 6 foot or so of additional height that's had to be added since then (alas can't google it up right now.)

Here's the IPCC predictions for sea-level rise under various emission scenarios this century. A significant number of climatologists believe these numbers are significantly over-optimistic; I've seen figures of 15-25m (ie. 45 - 75 feet.) Obviously those scenarios would pretty much wipe out world civilisation as it is today, due to the loss of massive amounts of capital (all the human settlements closer than that to sea-level, which is a very large fraction), infrastructure and especially shipping disruptions.

Ironically, deep-sea oil and gas rigs float, so would be unaffected (except for the refining and distribution networks being wiped out, I suppose.)

A reasonable question. Here is the answer.

The only facts that Al Gore deals in are the ones he distorts for his twisted agenda.

Yawn. Gore has his opinions, but they are backed up by decades of impartial research. As opposed to you flat earthers, who rely on lies and asshatery.

I deal with the facts as they are. RealClimate is run by real partisans, bought and paid for by the State, some of whom have degrees.

Paid by the state? Do you have any idea who has been president for the last 6 years and who had control of Congress for the last 14? Have members of your family argued that keeping children away from lead paint and mercury out of their food were "real partisans?"

That link has nothing to do with ice cores. No climate scientist or anyone even vaugely aquanted with the data, would dispute that Antarctica is in a cooling trend according to the ice cores. I'm not going to do your research for you. Download some ice core data.

You expect me to prove your points for you? Find your own damned links, lazyass.

And, as I stated before, the antarctic is cooling, and even your flunkies at the IPCC would back me up on that one.

Once again, realities well known liberal bias and smacks down your bullshit, here and here.

Maybe you should try to think of the global economy as an ecosystem, and then you will start to see the light. You can't just say, oh, we'll just wipe out the plankton, big deal. It is a big deal with repercussions that far exceed what can be anticipated. Same thing with wiping out a major industry in the economy. Economic tampering by socialistic lunatics has the potential to bring far more suffering into the world than you are obviously aware. Even the minor U.S. political tampering with ethanol demand is already causing artificial food crises in various parts of the world. But it's a logical fallacy regardless to try to defend your position by saying that the consequences of your position are more terrible than my position. The bottom line is that your position is based on a combination of obsolete hypotheses, political opportunism, peer pressure, propaganda and lies. There's no reason for any reasonable person to believe in it, no matter how horrible its predictions are. If you want a doomsday prediction to guide science and government action, you should start thinking about the next ice age, which will mean the obliteration of life as we know it, and has the added advantage of being nonfictional.

Can be summarized as: E++99, low on facts, but has a lock on self-centered, irresponsible greed.

"Pay attention to what the real scientist are saying directly."

Good advice

"Seriously, please post if you find it."

You can ask some of the most respected aurthors of the IPCC report technical questions on this site, however if you are too lazy to look at the reference section of the IPCC when someone points it out to you I don't like you chances of getting an answer. And seriously, if you are serious you need to spend some cash to access journal articles (at a minimum "Nature" and "Science"). Suggesting the data and methodology is somehow more obscure than evidence used in other scientific fields is utter nonesense.

As for computer models, source code for many of them is not hard to track down using the RealClimate link above. In a nutshell, the "secret sauce" is finite element analysis.

"a bunch of bickering and bargaining until they could get a majority to vote for 80. Very scientific stuff."

You don't seem to understand that "bickering and bargaining" is "very scientific stuff", it's what the term "the republic of science" means and when applied to ~2800 scientists it results in a scientifically conservative document.

"Yeah, the best of luck to anyone trying to find actual methodology on the IPCC site."

Yes their web site is less than "user freindly" but that doesn't change the fact that the IPCC is a huge scientific effort rivaling such projects as the LHD or Nasa's "Great observatories".

Water vapor is not the most important greenhouse gas. Sure, it's trapping more heat than CO2 is. Thank god, or we'd freeze to death. But water vapor doesn't drive temperature change. It only reacts.

For instance, if you put several billion tons of CO2 into the atmosphere, the stuff stays up there. You put the same amount of H2O up into the atmosphere, it falls back into the oceans within days, long before it has a chance to change the heat balance of the planet.

The amount of H2O is pretty much a function of atmospheric temperature. When CO2 rises, temperature rises, so the atmosphere can hold more water. IOW, water vapor is a feedback agent, not a forcing agent. [more]

The "increase in plant growth" you attribute to CO2 is only true if all else is held constant. If the Earth gets hotter, and some areas get drier, then the increased CO2 will lead to less plant growth. But maybe that could be counterbalanced by increased plant growth in currently permafrosted areas. But won't the thawing of those areas release vast quantities of methane, another very important greenhouse gas? Anyhow, plants aren't likely to act as a CO2 sink for long.

Even if (as you believe, and I doubt) there is substantial disagreement about whether anything bad will happen, then we have a choice.

1) We do nothing. If you're right, climate change falls flat and we end up with a somewhat improved economy. If I'm right, all sorts of nasty things happen. Floods, droughts, mass extinctions, increased hurricane activity, and so on.

2) We devote a sizeable fraction of our economy to fighting climate change. If you're right, we just wasted a whole bunch of money, and will have to stagger along with a weaker economy than we would have had. If I'm right, climate change means avoiding devastation to vast swaths of the economy. I would also argue that a shift away from fossil fuels is going to carry all sorts of unrelated benefits, like increased energy security, reduced pollution, technological advancement, etc.

As the argument goes, we have no control over whether climate change is real. All we can control is our response. Knowing that climate change is possible, it strikes me as insane to wait until it's absolutely certain before deciding whether to respond. In terms of risk management, there is no reasonable alternative.

Water vapor is not the most important greenhouse gas. Sure, it's trapping more heat than CO2 is. Thank god, or we'd freeze to death. But water vapor doesn't drive temperature change. It only reacts.

For instance, if you put several billion tons of CO2 into the atmosphere, the stuff stays up there. You put the same amount of H2O up into the atmosphere, it falls back into the oceans within days, long before it has a chance to change the heat balance of the planet.

The amount of H2O is pretty much a function of atmospheric temperature. When CO2 rises, temperature rises, so the atmosphere can hold more water. IOW, water vapor is a feedback agent, not a forcing agent. [more]

The "increase in plant growth" you attribute to CO2 is only true if all else is held constant. If the Earth gets hotter, and some areas get drier, then the increased CO2 will lead to less plant growth. But maybe that could be counterbalanced by increased plant growth in currently permafrosted areas. But won't the thawing of those areas release vast quantities of methane, another very important greenhouse gas? Anyhow, plants aren't likely to act as a CO2 sink for long.

Even if (as you believe, and I doubt) there is substantial disagreement about whether anything bad will happen, then we have a choice.

1) We do nothing. If you're right, climate change falls flat and we end up with a somewhat improved economy. If I'm right, all sorts of nasty things happen. Floods, droughts, mass extinctions, increased hurricane activity, and so on.

2) We devote a sizeable fraction of our economy to fighting climate change. If you're right, we just wasted a whole bunch of money, and will have to stagger along with a weaker economy than we would have had. If I'm right, climate change means avoiding devastation to vast swaths of the economy. I would also argue that a shift away from fossil fuels is going to carry all sorts of unrelated benefits, like increased energy security, reduced pollution, technological advancement, etc.

As the argument goes, we have no control over whether climate change is real. All we can control is our response. Knowing that climate change is possible, it strikes me as insane to wait until it's absolutely certain before deciding whether to respond. In terms of risk management, there is no reasonable alternative.

My intent on posting such admittedly one-sided information was to point out there there were some very observable climate changes occurring right now which one does not need a degree in science or statistics to understand. The particular examples I have picked (especially those concerning the glaciers and North Pole) were intended to present scenarios outside of human experience: sea captains have never been able to navigate a northwest passage in recorded human history and many have died trying. Glacial creep is unbelievably easy to both measure (by experts) and observe by novices. Some of the glaciers in the Alps have been portrayed in landscapes for the last couple of centuries and so comparisons between then and now are possible. When one also analyzes the geological record, it's clear that such glacial recessions in these areas haven't happened for thousands of years. Critics of climate change that have posted here have either not acknowledged such obvious examples, or have stated that solar cycles or the precession of the Earth explain this stuff (without offering any data). My critiques of the solar cycles or precession explanations are that they are built into the models that are so soundly criticized by opponents of climate change: one one hand the opponents hate the models, and on the other hand they use them when their purposes are suited.

The true list of both sides of data is at realclimate. There they fairly discuss both sides of the data (for example the fact that there have been some *gains* in glaciation in Greenland and elsewhere) - and then they put it in the context of ALL of the data. It turns out that such gains are the exception rather than the rule. Unfortunately, the site realclimate.org has been designated here as a left-wing conspiracy so I have tried to avoid linking to it even though it really is a data clearing-house.

All of us who have been presenting evidence of any sort have been soundly criticized as being zealots by folks who have stated that graphs are just a bunch of meaningless numbers and the like. In short the critics of climate change seem to me to be intentionally vague or fond of citing outdated data (IPCC 1) vs (IPCC 4). A number of sites have old links to early IPCC reports that do not include some of the fluid dynamics that are being observed in the Antarctic ice sheets (melting begets more melting in a very non-linear way), sea level rise, and new estimates of carbon emissions.

I myself (as someone with an M.A. from the Center for Space Physics at BU) have revised my opinion of global warming quite a lot since the early 1990s - but only by keeping up with what is happening.

"What tools are these you speak of?"

Ok, I'm not talking about Atlantic hurricanes in particular and I agree the models failed to predict that particular region (not entirely a bad thing since when things go wrong we learn more - in this case wind shear from a changed jet stream was found to kill storm development). IANAC so if I am to be part of the discussion I need to accept that the IPCC report describe what is otherwise known as "the consensus" and examine their assumptions. The IPCC reports predict that storms in general will be more severe and/or more common, that certainly looks to be the case on a global scale but the jury is still out since the level of certainty is weak.

If the models were only predicting temprature then yes you could create a simple fit with a calculator and extrapolate. However the models take in a myriad of factors of varying certainty and predict such things as "polar amplification" that field scientists then go and look for (and in that case found). Also there is no single model, there are many different models with different resolutions and different emphasis on things like areosols, GHG concentrations, feedbacks, ect, ect. The IPCC takes the "average" of those models for particular emmision scenarios that range from "bussiness as usual" to "a complete halt".

In essence they use "finite element analisis" to do the calculations so the basic idea is just as sound as the models used to calculate spaceship trajectories, certainly not as accurate but there is still much to learn.

The word "reliable" is very subjective, the IPCC use "certainty estimates" to try and quantify it. If you want to find out more the IPCC reports are here, the working group II SPM is probably the most relevant. Another excellent source written by climatologists and aimed at the educated layman is here.

"what Dyson was talking about"

I don't think Dyson is wrong when he says the models could be improved, in fact the IPCC reports list the same "problems" as "poorly understood". I think he is wrong when he implies climatologists are not "real" scientists, implies the models are useless, neglegts to mention that the IPCC reports agree with his list of "problems" and published them in the 2007 SPM, and neglects to mention that solving the "problems" will not radically change the prognosis but will simply narrow the error bars. All of that is part of the "consensus" so to my way of thinking he is arguing against a strawman when he implies climatologists think otherwise. I would rather he had put his considerable brain-power towards solving some of the problems.

My original point that is now modded to hell by the astroturfers who came thru of the second day was that in this particular abstract he is acting as an authority figure throwing stones at climatologists rather than the "heritical" role he is (admirably) trying to promote. Herasy (skeptcisim) is more than just shouting bullshit on a "gut feeling", IMHO he has failed skeptics-101 in TFA because he failed to be skeptical of his own example.

"How do the models account for..."

Do I look like your personal research assistant? These climatologists may be able to help you if you ask politely.

"I do not doubt the validity of the models given our current level of understanding, the data is what concerns me."

Healthy skepticisim says you should continue to question both....forever!

1934 and all that

"I am old enough to remember when everybody railed about global cooling (about 30 years ago)."

And I am old enough to call bull on your pseudo memories.

Is this really the sum total of what "skeptics" bring to the table? Or was this entire post some truly subtle satire which I entirely missed?

See this from some climate scientists.

http://www.realclimate.org/index.php/archives/2007 /08/1934-and-all-that/

Real Climate replies to that "bug". Based on the information provided by RealClimate.com, this glitch affects only US temperature measurements (which is only one part of the global temperature measurements). http://www.realclimate.org/index.php/archives/2007 /08/1934-and-all-that/ Additionally, when you look at the graphs in the RealClimate article, it's clear that there is an temperature increase over time. Comparing those graphs to the statement below, it seems like the text below is attempting to deliberately obscure the fact that warming is happening. "NASA has now silently released corrected figures, and the changes are truly astounding. The warmest year on record is now 1934. 1998 (long trumpeted by the media as record-breaking) moves to second place. 1921 takes third. In fact, 5 of the 10 warmest years on record now all occur before World War II. Anthony Watts has put the new data in chart form, along with a more detailed summary of the events."

"at the very least the models have a big flaw"

All models have flaws of varying sizes, that is why there are so many of them. However Dyson is arguing a strawmam of his own construction. Putting to one side his ad-homs against climatologists, the IPCC reports specifically state that there is a low level of scientific understanding (LoSU) in the areas he picks on (see for example the attribution graph in the 2007 IPCC SPM). Even if we had a perfect model for the things he objects to it would not significantly change the basic attributions that lead to usefull models.

Sorry but Dyson can't argue for the scientific method and then argue that the models constructed using said method are "not science" simply because they conflict with his opinion.

More importantly for climate purposes, the longer term US averages have not changed rank. 2001-2006 (at 0.66 C) is still warmer than 1930-1934 (0.63 C - the largest value in the early part of the century) (though both are below 1998-2002 at 0.79 C). [...]

Gen IV does not finish design for 25 years. The new reactor that is moving forward the fastest is Calvert Cliffs 3, a run-of-the-mill light water reactor. I suspect this one will have trouble. While the nuclear power industry is talking about global warming all the time now, they seem pretty foolish to be betting on a sea level reactor as their first new project since the Three Mile Island and Chernobyl disasters made clear what a problem nuclear power is. The rise in sea level is 5 cm every 15 years and the rate is doubling every 15 years, so from its current level http://www.realclimate.org/images/sealevel_2.jpg, in 45 years you get 35 cm of sea level rise, enough to make the foundations pretty soggy. That would be about halfway through the life of the plant. 90 years out you get more than 3 meters with a doubling projection. That makes a very difficult mess to clean up. Think New Orleans Lower Ninth Ward. There is more to read about this problem here: http://mdsolar.blogspot.com/2007/08/cliffhanger.ht ml, including a link to a study on proposed sea level reactors in the UK.

The guys over at RealClimate have a pretty detailed rundown on what actually happened. Apparently the source of the error was a mis-synchronization between two data sets. The corrected data data does rearrange the ranking of warmest years (for the US only), but the actual changes are tiny, ~0.1C and within the error bars. The overall temperature trend is unchanged. So, basically, the change has high media value and essentially no scientific relevance.

From experience, this sort of thing happens all the time in all scientific fields. Errors get made, they get caught, and they get fixed. If the subject was anything at all other than global warming, no one outside of the field would have noticed or cared.

I'm going to respond to myself, since I found actual information at http://realclimate.org/: It's not a Y2K bug at all, but a change in sources of temperature data that had not been calibrated with respect to each other. And it's not the gargantuan error that some people seem to be thinking. The anomalies for 1998 and 1934 used to be +1.24 degrees and +1.23 degrees, a difference of 0.01 degree. Now it's the other way around. And the long-term trend is unaffected. The uncertainties in data collection methods over the last 70 years mean that differences of less than 0.1 degree are not considered significant, so we're talking about changes *an order of magnitude* too low to even discuss meaningfully, much less get excited about.

I don't pretend to be a climatologist, merely someone who knows about statistics. I don't think anyone argues that a simple linear regression is evidence for global warming. I certainly don't.

There are sites put together by people who study this stuff in depth. If you're curious about the details of climate change arguments, rates of change, and pre-historical climate change, RealClimate is a good place to start.

The classic paper on this is: Jones PD, Groisman PYa, Coughlan M, Plummer N, Wangl WC, Karl TR (1990) Assessment of urbanization effects in time series of surface air temperatures over land. Nature 347:169-172. This conclusion was refreshed by Easterling '97.

The IPCC TAR stated:

These results confirm the conclusions of Jones et al. (1990) and Easterling et al. (1997) that urban effects on 20th century globally and hemispherically averaged land air temperature time-series do not exceed about 0.05C over the period 1900 to 1990 (assumed here to represent one standard error in the assessed non-urban trends).

There have been a couple of recent papers that Steve has been looking at, but as his site is down I don't have the citations handy (and I don't know them off-hand).

You should be careful with realclimate.org. While the site is climate science by climate scientists, it is characterized by evangelism rather than objectivity. This isn't to say their evangelism isn't often scientific and correct, but they do distort, obscure, and ignore information that hurts their evangelism.

As it happens, Steve started his blog climateaudit.org after he was subject to smear campaigns on realclimate.org over a couple of papers he published demolishing the statistical techniques used in MBH'98. Judge for yourself: MM'05, rc1, rc2, Recap

Steve's papers were ultimately vindicated by a NAS panel review. A copy of which Steve posted on his website: Wegman Report