Not just warmer: it's the hottest for 2,000 years (whine alert)

The earth is warmer now than it has been at any time in the past 2,000 years, the most comprehensive study of climatic history has revealed. Confirming the worst fears of environmental scientists, the newly published findings are a blow to sceptics who maintain that global warming is part of the natural climatic cycle rather than a consequence of human industrial activity.

Prof Philip Jones, a director of the University of East Anglia's climatic research unit and one of the authors of the research, said: "You can't explain this rapid warming of the late 20th century in any other way. It's a response to a build-up of greenhouse gases in the atmosphere."

The study reinforces recent conclusions published by the UN's intergovernmental panel on climate change (IPCC). Scientists on the panel looked at temperature data from up to 1,000 years ago and found that the late 20th century was the warmest period on record.

But the IPCC's report was dismissed by some quarters in the scientific community who claimed that while the planet is undoubtedly warming, it was warmer still more than a thousand years ago. So warm, in fact, that it had spurred the Vikings to set up base in Greenland and led to northern Britain being filled with productive vineyards.

To discover whether there was any truth in the claims, Prof Jones teamed up with Prof Michael Mann, a climate expert at the University of Virginia, and set about reconstructing the world's climate over the past 2,000 years.

Direct measurements of the earth's temperature do not exist from such a long time ago, so the scientists had to rely on other indicators of how warm - or not - the planet was throughout the past two millennia.

To find the answer, the scientists looked at tree trunks, which keep a record of the local climate: the rings spreading out from the centre grow to different thicknesses according to the climate a tree grows in. The scientists looked at sections taken from trees that had lived for hundreds and even thousands of years from different regions and used them to piece together a picture of the planet's climatic history.

The scientists also studied cores of ice drilled from the icy stretches of Greenland and Antarctica. As the ice forms, sometimes over hundreds of thousands of years, it traps air, which holds vital clues to the local climate at the time.

"Drill down far enough and you could use the ice to look at the climate hundreds of thousands of years ago, but we just used the first thousand metres," said Prof Jones.

The scientists found that while there was not enough good data to work out what the climate had been like in the southern hemisphere over that period, they could get a good idea of how warm the northern hemisphere had been.

"What we found was that at no point during those two millennia had it been any warmer than it is now. From 1980 onwards is clearly the warmest period of the last 2,000 years," said Prof Jones.

Some regions may well have been fairly warm, especially during the medieval period, but on average, the planet was a cooler place, the study found.

Looking back over a succession of earlier centuries, the temperature fluctuated slightly, becoming slightly warmer or cooler by 0.2C in each century. The temperature has increased by at least that amount in the past 20 or so years, the scientists report in the journal Geophysical Research Letters.

"It just shows how dramatic the warming has been in recent years," said Prof Jones.

Scientists who do not believe that carbon dioxide is driving climate change are unlikely to run up the white flag just yet, however.

Dr Sallie Baliunas at the Harvard College Observatory in Massachusetts, for example, maintains that the recent warming could all be down to changes in the strength of sunlight falling on the planet.

She concluded that during the 20th century, earth went through a cycle of natural climatic change. According to her data, from 1900 to 1940 the planet warmed slightly, then cooled from 1940 until 1970, then warmed up again from 1970 onwards. Given that 80% of the world's carbon dioxide emissions have been produced since 1940, the expected effect, if carbon dioxide was causing global warming, would be higher temperatures not lower, she said.

Dr Baliunas's data also concluded that the period of warming between 1900 and 1940 must have been due to natural causes, most likely increased sunlight hitting the earth's surface, since carbon dioxide emissions were negligible at the time. The evidence, she said, pointed to variations in the sun's brightness being the cause of the planet's warming up, not carbon dioxide.

But other climatologists have welcomed the new study as the most conclusive evidence to date that the increase in temperature is a result of human activity.

"The importance of the finding is that it shows there's something going on in the climate system that's certainly unusual in the context of the last 2,000 years, and it's likely that greenhouse gases are playing the major role," said Prof Chris Folland of the Met Office's Hadley Centre. "If you look at the natural ups and downs in temperature, you'll find nothing remotely like what we're seeing now."

Not everyone agrees that climate change is largely driven by human activity. Some believe the warming the planet is experiencing now is part of a natural cycle. Historical anecdotes are sometimes used to support their case, but the new study debunks these claims.

There were indeed vineyards in Britain in the 10th and 11th centuries, but only 50 to 60. There are now more than 350 in this country, with some as far north as Leeds.

In AD980, Erik the Red and his crew headed from Iceland to Greenland, but it wasn't for the good weather. Erik had been kicked out of Iceland for murder so he took his crew westward where, they were told, they would find land.

The river's tendency to freeze over frequently in the 16th and 17th centuries is often cited as evidence that the climate used to be more erratic. But, according to the new study, the major cause was the original London Bridge, completed in the 13th century, which had very small spans between its supports for the Thames to run through. The result was that the river was tidal only as far as the bridge, causing the water to freeze over. When the bridge was rebuilt to a different design in the 1820s, the water flowed more easily and therefore became less prone to ice.

It would seem to be the clear nonsense you are engaging in. If you think the whole bunch of people whom you respect and trust have answered, e.g., a Lomberg, you'd be wrong. They've only called him names.

What BigAndy doesn't seem to get is that no amount of proceduralism makes the slightest impression when the underlying subject is a question of scientific truth. He expects to get points for being conventional, for trying to appear polite, and other minor arts of politics. And expects anyone not doing so to be dismissed out of hand regardless of substantive arguments, or the lack thereof.

Fundamentally, he considers the entire thing purely a matter of politics, not a matter of science. It is inconceivable to him that there might be more scientific integrity in a minority than in the majority of his "whole bunches". He doesn't understand them, or their critics, and he doesn't even bother to try.

And he just doesn't notice that not bothering to try makes him irrelevant to the actual debate. By his own admission, he knows nothing about the actual subject and can't judge independently. Whether he realizes it or not, that means he simply isn't a participant in the debate at all.

The truth in the matter will out eventually. Epicycle hunts collapse ingloriously, though sometimes it takes a while (like, until those who built their career on a given theory die off). The only question is whether anyone in public life will be on right side when that happens.

He'd like the Republicans to go over to the wrong side, of course, because it is a matter of politics and liberal opinion is rabid on the subject. That he is abandoning the truth by doing so doesn't bother him, because he is equally ignorant on either side. What shocks him is simply that some people care about the actual truth of the matter.

The Press Gets It Wrong

Our report doesn't support the Kyoto treaty.

BY RICHARD S. LINDZEN Monday, June 11, 2001 12:01 a.m. EDT

Last week the National Academy of Sciences released a report on climate change, prepared in response to a request from the White House, that was depicted in the press as an implicit endorsement of the Kyoto Protocol. CNN's Michelle Mitchell was typical of the coverage when she declared that the report represented "a unanimous decision that global warming is real, is getting worse, and is due to man. There is no wiggle room."

As one of 11 scientists who prepared the report, I can state that this is simply untrue. For starters, the NAS never asks that all participants agree to all elements of a report, but rather that the report represent the span of views. This the full report did, making clear that there is no consensus, unanimous or otherwise, about long-term climate trends and what causes them.

As usual, far too much public attention was paid to the hastily prepared summary rather than to the body of the report. The summary began with a zinger--that greenhouse gases are accumulating in Earth's atmosphere as a result of human activities, causing surface air temperatures and subsurface ocean temperatures to rise, etc., before following with the necessary qualifications. For example, the full text noted that 20 years was too short a period for estimating long-term trends, but the summary forgot to mention this.

Our primary conclusion was that despite some knowledge and agreement, the science is by no means settled. We are quite confident (1) that global mean temperature is about 0.5 degrees Celsius higher than it was a century ago; (2) that atmospheric levels of carbon dioxide have risen over the past two centuries; and (3) that carbon dioxide is a greenhouse gas whose increase is likely to warm the earth (one of many, the most important being water vapor and clouds).

But--and I cannot stress this enough--we are not in a position to confidently attribute past climate change to carbon dioxide or to forecast what the climate will be in the future. That is to say, contrary to media impressions, agreement with the three basic statements tells us almost nothing relevant to policy discussions.

One reason for this uncertainty is that, as the report states, the climate is always changing; change is the norm. Two centuries ago, much of the Northern Hemisphere was emerging from a little ice age. A millennium ago, during the Middle Ages, the same region was in a warm period. Thirty years ago, we were concerned with global cooling. Distinguishing the small recent changes in global mean temperature from the natural variability, which is unknown, is not a trivial task. All attempts so far make the assumption that existing computer climate models simulate natural variability, but I doubt that anyone really believes this assumption.

We simply do not know what relation, if any, exists between global climate changes and water vapor, clouds, storms, hurricanes, and other factors, including regional climate changes, which are generally much larger than global changes and not correlated with them. Nor do we know how to predict changes in greenhouse gases. This is because we cannot forecast economic and technological change over the next century, and also because there are many man-made substances whose properties and levels are not well known, but which could be comparable in importance to carbon dioxide.

What we do is know that a doubling of carbon dioxide by itself would produce only a modest temperature increase of one degree Celsius. Larger projected increases depend on "amplification" of the carbon dioxide by more important, but poorly modeled, greenhouse gases, clouds and water vapor.

The press has frequently tied the existence of climate change to a need for Kyoto. The NAS panel did not address this question. My own view, consistent with the panel's work, is that the Kyoto Protocol would not result in a substantial reduction in global warming. Given the difficulties in significantly limiting levels of atmospheric carbon dioxide, a more effective policy might well focus on other greenhouse substances whose potential for reducing global warming in a short time may be greater. The panel was finally asked to evaluate the work of the United Nations' Intergovernmental Panel on Climate Change, focusing on the Summary for Policymakers, the only part ever read or quoted. The Summary for Policymakers, which is seen as endorsing Kyoto, is commonly presented as the consensus of thousands of the world's foremost climate scientists. Within the confines of professional courtesy, the NAS panel essentially concluded that the IPCC's Summary for Policymakers does not provide suitable guidance for the U.S. government.

The full IPCC report is an admirable description of research activities in climate science, but it is not specifically directed at policy. The Summary for Policymakers is, but it is also a very different document. It represents a consensus of government representatives (many of whom are also their nations' Kyoto representatives), rather than of scientists. The resulting document has a strong tendency to disguise uncertainty, and conjures up some scary scenarios for which there is no evidence.

Science, in the public arena, is commonly used as a source of authority with which to bludgeon political opponents and propagandize uninformed citizens. This is what has been done with both the reports of the IPCC and the NAS. It is a reprehensible practice that corrodes our ability to make rational decisions. A fairer view of the science will show that there is still a vast amount of uncertainty--far more than advocates of Kyoto would like to acknowledge--and that the NAS report has hardly ended the debate. Nor was it meant to.

Mr. Lindzen, a professor of meteorology at MIT, was a member of the National Academy of Sciences panel on climate change.

By the way, one of the 'Global Warming Petition' proponents is Frederick F. Seitz, past president of the NAS.

You are operating under the mistaken impression that scientists have not heard my arguments or have answers to them. They have and they don't. I'm not confident in what I'm saying because I am peddling it to non-experts. I'll explain it patiently to anybody, and have, to many scientists. The test in science, though, is not whether everyone agrees with you (agreement is subjective and irrelevant), it is whether they have any *substance* to offer, in the form of evidence or argument, against your claims or criticisms.

The entire global warming establishment is madly searching for power amplifiers, because everything I've said is an open secret to anyone who bothers his head with the actual science. If you think I'm just making it up, read Lomberg's whole chapter on global warming. They know they have to find a lot more power.

They've looked in clouds and water vapor and aerosols and they are still looking. They haven't found it. All the items they've come up with so far are significantly smaller than the original direct greenhouse - see IPCC again. They need something largely, perhaps 10 times as large, with the right sign. Instead they know have 12 different categories with random signs all an order of magnitude smaller. See Lomberg's IPCC on p. 268

You are supposed to look at that and think, "gee, greenhouse is real and the significant thing going on, there must be 5C warming just like they say". What it actually says to the knowing is they still only have a couple of watts.

Peddling a theory over and over again to non-experts is what the global warming crowd has been and is doing. And you are right, it does not make them right. Who is right and who isn't has nothing to do with procedures or opinions.

As for being headstrong about it, one of my favorite philosophy of science quotes is from Popper, famous for requiring a test of falsifiability. He once said "a certain amount of dogmatism and pigheadedness is necessary in science." I can, incidentally, tell you exactly what would convince me. A power term 10 times the size of what they have, positive in sign, clearly linked causally to past warming and CO2 in particular. Or if it is easier, any cogent explanation of my own error, anywhere in my chain of reasoning.

Now, BigAndy, tell us any scientific observation or argument that would lead you to reject your belief in global warming, on the substance, independent from any opinion of anyone else. If all you can say is "I'll believe whatever these guys tell me", then you just aren't in the science side of the debate. And your opinion on the matter has nothing to do with science. It is pure faith in a body of men.

Speaking of things that should be easy, BigAndy, why don't you just go to your authorities and find the answer to my question about the power source. Since they have one (you obviously think), they will know what it is. Ask them, or look it up in their reports. Should be easy. Then come back and tell us all what it is. If you prefer, send one of them to tell us what it is.

This is how actual scientists engage critics. They go straight to the substance. (They positively love the substance). If they instead rely on lists of people who agree with them, it is a Bad Sign (tm).

”Hmm. OK, I think I get the basic drift of a kettle argument.”

You understand the kettle argument now. If you do agree that a candle can not warm up a very large kettle then you are in direct disagreement with your so-called ‘experts’. If you asked them what other heat source there is they will not answer you because they don’t have one. That means your ‘experts’ are at not experts in science they are experts in politics.

“I suggest you talk to the scientific community… “

Many years ago I was discussing this question with a University professor that was working on the causes of global warming. I asked him, explain to me how Egypt, Mesopotamia and that region warmed up. When Egypt was building their pyramids the whole area was tropical, now it is desert.

He told me, “that was most likely due to the Egyptians and Mesopotamia’s clear cutting the forests in order to plant crops. When man striped the soil it just became an oven.” I asked him is it possible that the Sun and earth has cycles that we are unaware of? He said, “there is no evidence of that.” .” I said there is no evidnce that man did it either, you are a scientist you must prove it. He said, “we would need weather charts thousands of years old to see the weather patterns and acient people didn’t keep track of their weather..” I told him Tree rings and ice cropping can do that. Not long afterthat the same nutcase formed a team on my tax dollars to go study ice croppings for the first time for weather patterns, other teams latter followed. They latter miraculously discovered that the earth goes through cycles but of course they discounted that as the reason for the warming. It was obviously man's fault.

If it was mans fault explain to me the "Medieval Minimum” from 400 to 700 AD Romen rivers where covered in ice that barbarians crossed? Or the Spoere Minimum or sometimes called the Maurder Minimum that occurred with in 1400 to 1700 AD. These where considered 'mini Ice ages.' Then there was the Roman Maximum which was in 50 BC to 100 AD which the earth is estimated to be 4 to 5 degree warmer then today.

How did man create this? The so called experts can not give you an answer because they do not have one. That is JasonC's point. They do NOT have the answers and the ones they do give are faults.

I honestly don't think BigAndy's belief system is wedded to global warming. I think it is wedded to Bush, proceduralism, conventionality, and a desire to all get ahead by all getting along. Which in politics are all decent things. They are just out of place in science, that's all.

He'd like the right to think, OK, Bush said he was skeptical and put together a panel to look into it. His panel looked into it and (he thinks) supported the global warmers and their conventional wisdom on the subject. Now he wants to accept that and move on. He wants to abandon the fight as lost, or if yet winnable, to be won by somebody else, not Bush and company. He thinks this is the essence of sweet reason.

If he looked into the details he'd find there is consensus on inessentials but no consensus on the critical issue, the scale of expected future warming. Saying so publically would incur the wrath of the entire left. But it is the actual position of science on the matter, for the excellent reason that the skeptics noticed they didn't have enough power, and despite years spent turning over every available rock looking for more, they still don't.

But geez that is messy. It means respectable people can't simply be listened to respectfully and dutifully agreed with. It means there is an actual truth in the matter - always scary to pols - and a definite chance of being utterly in the wrong. Pols can't be expected to know a power from an energy from an entropy from their anatomy. "You can't possibly expect us to have actual intellectual opinions on this matter", they practically beg.

They are in an impossible spot, from the standpoint of anyone unable or unwilling to get in to the actual science of it all. There is no scientific consensus about the degree of future warming. But there is rabid scientific and liberal opposition to pointing out this patently obvious fact.

There is no easy-going scientific consensus that it is an open matter for future investigation, that we should all calm down and wait for more data. Because it is the world project of the entire modern left at stake here - not to mention a Pascalian argument from practical damnation. People aren't just wondering how clouds work, they are stating their practical allegiances.

Scientists say privately that Lomberg wrote a good book, but that this can't be stated publically. They say the whole issue is absurdly over politicized. Some see that the whole affair is a scandal of the first order of magnitude for modern science. Pity the naive and trusting pol just trying to do the right thing, trying to navigate it all - without ever cracking a book.

If you're going to paraphrase me, please, please try to get it right. You say: "Now he wants to accept that and move on. He wants to abandon the fight as lost, or if yet winnable, to be won by somebody else, not Bush and company."

I said: "[we should] ensure continuing independent research is carried out (by similar national and international bodies) to keep our level of knowledge of this area up to scratch" This is hardly abandoning any fight as lost - not least because I don't see it as a fight, more as a reasoned approach to try to reach a balanced view of what's really going on.

Your continuing inaccurate parsing of my arguments doesn't make yours any stronger. Nor does your (mis)interpretation of my motives - which I've already stated quite clearly.

Your thread is entering the realm of nonsense now. (Examples, so you don't think I'm making it up "He thinks this is the essence of sweet reason."; "there is consensus on inessentials"; "respectable people can't simply be listened to respectfully and dutifully agreed with. It means there is an actual truth in the matter"; '"You can't possibly expect us to have actual intellectual opinions on this matter"'; "Because it is the world project of the entire modern left at stake here".)

All nonsense. One of the beautiful things about free speech is that you can write what you like, and you'll usually find one or two people to agree with you. Keep it up. I'll stick to rigor.

Speaking as a climatologist (Specifically, I am in the discipline of geography) I do not believe this to be true. The anthropogenic impact on climate is generally accepted. Of course, the debate on what (if any) beaurocratic/political responses to global climate variability are appropriate is as vigorous within atmospheric science circles as it is outside of them... (Not to say there aren't debates within climatology, but these are more related to the magnitude or relative importance of human impacts, rather than to their existence.)

I can just quote a real world-class climatologist:

In the early 1990s Lindzen was asked to contribute to the IPCC's 1995 report. At the time, he held (and still does) that untangling human influences from the natural variation of the global climate is next to impossible. When the report's summary came out, he was dismayed to read its conclusion: "The balance of evidence suggests that there is a discernible human influence on global climate." "That struck me as bizarre," he says. "Because without saying how much the effect was, the statement had no meaning. If it was discernible and very small, for instance, it would be no problem." Environmentalist Bill McKibbon referred to this phrase in an article in The Atlantic in May 1998: "The panel's 2,000 scientists, from every corner of the globe, summed up their findings in this dry but historic bit of understatement." In an angry letter, Lindzen wrote that the full report "takes great pains to point out that the statement has no implications for the magnitude of the effect, is dependent on the [dubious] assumption that natural variability obtained from [computer] models is the same as that in nature, and, even with these caveats, is largely a subjective matter."

Now, if I wanted to be one of those ponderous scientific people, and "let on" to prove what had occurred in the remote past by what had occurred in a given time in the recent past, or what will occur in the far future by what has occurred in late years, what an opportunity is here! Geology never had such a chance, nor such exact data to argue from! Nor "development of species," either! Glacial epochs are great things, but they are vague--vague. Please observe:--

In the space of one hundred and seventy-six years the Lower Mississippi has shortened itself two hundred and forty-two miles. That is an average of a trifle over one mile and a third per year. Therefore, any calm person, who is not blind or idiotic, can see that in the Old Oölitic Silurian Period, just a million years ago next November, the Lower Mississippi River was upwards of one million three hundred thousand miles long, and stuck out over the Gulf of Mexico like a fishing rod. And by the same token any person can see that seven hundred and forty-two years from now the Lower Mississippi will be only a mile and three quarters long, and Cairo and New Orleans will have joined their streets together, and be plodding comfortably along under a single mayor and a mutual board of aldermen. There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
Mark Twain, Life on the Mississippi, Chapter XVII (Pg 209)

Rigor? lol. You haven't put two sentences together with any scientific or even logical rigor since I got here.

As for my supposed nonsense, you have told us yourself that you don't consider yourself qualified to have any opinion on the substance, and that you are entirely in the hands of authorities, whom you choose to trust or not to trust based entirely on externals. Which means you do not have an intellectual opinion on the matter, just as I said. The price of admission to the debate on global warming is cracking a book and learning some of the actual scientific issues involved. Everything offered by those who haven't bothered to pay that price is just noise, and doesn't decide a thing. It doesn't matter how many parrots repeat each opinion. Truth is not a matter of votes.

As for what scientists will think or at least say about a small candle and a big kettle, they say "climate sensitivity is an important unknown parameter". Then they say it is probably high. Then they impute all past observed delta T to whatever signal sources they've already IDed, instead of doing it the other way around and calculating (from physical law) how much of the observed past delta T can be attributed to e.g. CO2 greenhouse. Then they take their empirical coefficient (from some regression probably) and heroically project it into a future scenario with 2-3 times the CO2.

Others then point out, "there isn't enough power for that much delta T". Oops. So they need to look for more. That starts with handwaving "its somewhere in the complexity of climate". That scares off those who think they don't understand climate or that it is hopeless to analyse the complexity. But others remain, empirically minded and eager to go look, and ask "where?" So hand waving must give way to specifics.

So they said "clouds". Physicists looked. Clouds are modest net coolers. You might get enough if every one dropped out of the sky, forever. Meanwhile they looked at what clouds have actually done in response to the warming that has already occurred. They got marginally thicker (like a tenth of a percent). Slight negative not positive feedback. Wrong sign. Order of magnitude off by 3 (for those in Rio Linda, that means by a factor of 1000). You couldn't ask for a more definite proof they were flat guessing.

So they said "aerosols". Wrong sign. Uncertainty as big as the signal. Could be zero, could be minus 1-2 watts. Still off by at least 1 order of magnitude and in the wrong direction. They are spinning that one now for all they are worth. The script at present is, since aerosols have been cooling things so much, it must be CO2 that is warming them up more to overcompensate.

So the temperature sensitivity is supposed to be 2-3 times what they thought it was before they looked at aerosols. Which can be projected to a scarier scenario, without aerosols helping anymore. But solving their power problem? That is made harder by this spin, not easier. Because now they are effectively saying it could have warmed 0.5C in response to only about 1W of net signal, for greenhouse plus aerosols.

Anything they find that gives them more power means the future power will be higher and thus future temperatures will be higher. Anything they find that takes power away means the past power was lower but supposedly still caused all of the past temperature change. Therefore climate sensitivity is higher. Therefore future temperature changes will be higher. If they find power, future temps up. If they find negative power, future temps up. This is called "non-falsifiability" and is not a Good Thing (tm).

But that is just at the level of spin. They know perfectly well they have to find power or the future predictions are wildly implausible. They just haven't. There are a dozen other places they looked - you can see them all in the IPCC reports. If they found the real thing, it would be a vertical bar above the zero line vastly larger than the direct greenhouse bar over on the left of their "watts forcing" diagram. Instead you see a whole string of tiny bars a tenth the size, all with giant errors, randomly positive or negative.

Can you say "epicycle hunt"?

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