NASA’s Dr. James Hansen once again goes over the top. See his most recent article in the UK Guardian. Some excerpts:
“The trains carrying coal to power plants are death trains. Coal-fired power plants are factories of death.”
And this:
Clearly, if we burn all fossil fuels, we will destroy the planet we know. Carbon dioxide would increase to 500 ppm or more.
Only one problem there Jimbo, CO2 has been a lot higher in the past. Like 10 times higher.
From JS on June 21, 2005:
One point apparently causing confusion among our readers is the relative abundance of CO2 in the atmosphere today as compared with Earth’s historical levels. Most people seem surprised when we say current levels are relatively low, at least from a long-term perspective – understandable considering the constant media/activist bleat about current levels being allegedly “catastrophically high.” Even more express surprise that Earth is currently suffering one of its chilliest episodes in about six hundred million (600,000,000) years.
Given that the late Ordovician suffered an ice age (with associated mass extinction) while atmospheric CO2 levels were more than 4,000ppm higher than those of today (yes, that’s a full order of magnitude higher), levels at which current ‘guesstimations’ of climate sensitivity to atmospheric CO2 suggest every last skerrick of ice should have been melted off the planet, we admit significant scepticism over simplistic claims of small increment in atmospheric CO2 equating to toasted planet. Granted, continental configuration now is nothing like it was then, Sol’s irradiance differs, as do orbits, obliquity, etc., etc. but there is no obvious correlation between atmospheric CO2 and planetary temperature over the last 600 million years, so why would such relatively tiny amounts suddenly become a critical factor now?
Adjacent graphic ‘Global Temperature and Atmospheric CO2 over Geologic Time’ from Climate and the Carboniferous Period (Monte Hieb, with paleomaps by Christopher R. Scotese). Why not drop by and have a look around?
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Hmmmm well Stephen Schneider of NCAR thought there was a consensus in the scientific community toward cooling in 1976, and that there was just beginning the drift toward the new “consensus” of global warming.
Here is what he had to say about it in his book
The Genesis Strategy
pg 10
So here you have one of the primary figures in the debate, a professional climate scientist at NCAR confirming that at that time circa 1976 there was according to him, a consensus among climatologists that the most likely effect was a cooling trend but that “recent research” was just beginning to make a small faction of “skeptics” contend that it would actually be a warming trend.
The fact is just like today, the research points in both directions and the perception depends on which parts of the reports are quoted and believed by a given individual.
There is absolutely no doubt that the general public was being inundated with a raft of articles in MSM and popular books based on these theories (remember there is a time lag between publication of the scientific studies and their diluted broadcast by the media). The consumer scientific publications and the high profile media like Time, were selling the coming global cooling thesis hard and heavy just like the AGW people are today, selling the warming thesis. Even though some research contains indications they maybe wrong they are going with the selectively quoted data that supports their “consensus”. You need to consider the informational inertia of the MSM it usually does not pickup major scientific trends until they are old hat in or even dieing in the research centers and colleges. The global cooling pitch sold particularly well in the 1970’s thanks to the OPEC oil embargo so one fed the other.
In short both of you are right, there was a consensus during that period that global cooling was a threat, but the CO2 warming thesis was just beginning to get traction, so both ideas were current but the MSM of the period were focusing on the older data that indicated cooling, while the cutting edge research was just beginning to try to build the case for CO2 warming.
I personally have no doubt about this, as I remember the period well! Punctuated by very cold winters in 1962, 1963 and 1972, and 1973. The winters of 62 and 63 were record cold winters here (Denver area), my brother got frost bite walking home from school and I was delivering news papers in temperatures cold enough (-30 deg F) that with windchill your eyes would freeze shut if they started to water and you held them closed too long. The winters of 72, and 73 had deep snow and unusually long hard cold snaps that everyone raged about as signs of the coming global chill, while they tried to figure out how to put gas in their cars and heat their homes. It snowed on Halloween night and we did not have the snow melt off until mid April (very unusual here, which resulted in the dethroning of a sitting Mayor of Denver because he did a crappy job of getting the mountains of ice and snow off the streets. I had a friend that worked on heavy equipment and he spent that winter putting new teeth on back hoe buckets because they were tearing them off as fast as he could fix them digging it concrete hard frozen ground. The north eastern U.S. had some major blizzards that practically shut that part of the country down.
I have several of those popular books which were pitching global cooling lying on the floor beside my chair at the moment, and bought them precisely because all the MSM were pitching that issue.
Larry
About that lack of concensus on a new ice-age in the seventies, there definitly was one both in the press and in science, and that concensus lasted a lot longer than just the early seventies.
One of the scenario’s that came with the global cooling scare was the horrific prospect of a full exchange of nuclear weapons between Nato and the Soviet-Union, the following nuclear winter caused by soot, smoke and other nasty things thrown into the atmosphere would throw us back into the stone-age. This scare was maintained right until the first Gulf-war (seccond if you count the Iran-Iraq war as well) when Saddam and his forces set fire to the Kuwait oil fields.
But the world as we know it did not end there, where still here.
Bill Illis (18:19:57) :
Thank you Bill. The info looks very useful.
David
Joel,
I lived through it.
I was a believer in the apocalyptic pap you guys were selling.
You are just posting a bunch of sef-referential rewrites, and you know it.
Just like the climate apocalypse your cult is currently fixated on, your rewrite is simply BS.
From http://www.green-agenda.com
“Then I discovered that many of them belonged to a group known as the Club of Rome. Current members of this ‘Club’ include Al Gore, Javier Solana, Bill Clinton, Mikhail Gorbachev, Tony Blair, Jimmy Carter, Stephen Scheider, Bill Gates, David Rockefeller, George Soros, Ted Turner and many other influential leaders. Sometimes I think this must just be a bad dream, but when you read what they say, in their OWN words, and then you see it all unfolding…
And so I have become personally convinced that ‘man-made’ climate change is a deceitful and devious fraud being used to implement a much deeper agenda. In order to protect Gaia from the ‘voracious beast of capitalism’ they must strike at the beast’s lifeblood – fossil fuels. And in order to transition to ‘sustainable global earth community’ they must implement a new form of governance which will allow them to control, and ultimately reduce, human activity on this planet.”
Bill Illis (18:19:57) :
To David Porter and tallbloke,
The Log CO2 warming chart comes from a post I did on adjusting temperatures for the influence of the ENSO, the AMO and an ocean index I added later the Southern AMO. I just wanted to pull out the natural variation of the climate and arrive at the global warming signal which remained.
If you want to see how the empirical temperature numbers to date square with global warming theory and the log warming chart, this zoom-in of the chart (covering CO2 from 270 ppm to 560 ppm) against all the major temperature series (including Hadcrut3, GISS, RSS, and UAH – NCDC would right in the middle as well) shows how the empirical evidence to date does not support the warming proposition.
http://img254.imageshack.us/img254/2626/tempobsrvvsco2ct4.png
A more conventional look with temperature versus time is this one.
http://img510.imageshack.us/img510/811/finalwarminggw8.png
Thanks Bill. Your finalwarming graph above, doesn’t seem to leave any room for increased solar activity in the C20th. Even the IPCC allow the sun some influence. Would this mean the warming for doubling co2 figure might be lower than 1.62C?
If natural variation takes temp down for an extended period of 15 years or more, which human co2 emissions continue upwards, do you think the upward trend of atmospheric co2 would slow, or even reverse?
Graeme Rodaughan (13:26:16) :
Hansen’s Catastrophism relies on the following concepts.
1. A CO2 Tipping Point.
2. Positive Feedback(s) post tipping point leading to Runaway Global Warming.
Could the AGW Proponents visiting this blog please provide the hard data, and empirical evidence of
1. The presence of a “CO2 Tipping Point”, and it’s measure, I.e at what point does it kick in. I.e not a hypothetical measure and no computer models that assume a CO2 tipping point.
2. The presence of positive feedbacks in the historical climate and how that is reconciled with cyclic climate behaviour (now that’s got to be a tough call, as it requires negative feedback to generate oscillation around a mean).
3. (A Q?) If there are no positive feedbacks in past climate – why are we being threatened with one now?
Mary, Flanagan, Foinavon???
I pointed it out to foinaven. Big fat silence since. They are here to tell us how stupid we are, not to answer acute, well directed, intelligent questions like yours Graeme.
In Joel Shore (14:21:53) : , Joel excuses the scientists of the 70s for not knowing enough about climate to make accurate predictions. However, that did not stop many of them.
Of course, were supposed to believe that these same scientists NOW understand it all perfectly even though new discoveries happen yearly.
Joel, you need to learn from the history, otherwise history is sure to repeat itself.
I’ve just spent way too much time reading through this extraordinary thread, but it was worth it to find some excellent posts by, among others, Mike D. (12:56:29) and (15:07:20), Daniel Lee Taylor (00:37:19), Graeme Rodaughan (01:36:19), tallbloke (07:46:14), Bruce Cobb (13:50:30), CodeTech (14:26:06), CodeTech (14:26:06), hunter (08:26:55), hotrod (10:11:13), and Graeme Rodaughan (13:02:26)—the times aren’t much help when looking through a thread several days long.
Re the last post on “Collusion of Means” by Graeme Rodaughan, he left out an important colluder: The avid socialists/communists who have jumped upon the ‘green’ bandwagon as the vehicle to achieve their ideological ends. Among these are some of the loudest proponents of AGW, who have admitted openly to using impending ‘crisis’ to frighten governments and voters into accepting draconian control over their businesses and their lives.
Also, while the chart of “Global Temperature and Atmospheric CO2 over Geologic Time” (from geocraft.com) in the original post has been the object of some discussion (even derision), it does suggest that there is no direct relationship between atmospheric CO2 and ‘global’ temperature over broad swaths of time, even if in short time spans (like the last few centuries) there seems to have been a rough correlation.
That rough correlation is enough, however, for the Alarmists to promulgate the idea that CO2 is endangering the planet. Controlling CO2 then becomes the perfect vehicle for the totalitarians to justify their agenda of taking control of the world’s economy.
The problem for Realists is that there is no comparable icon to counter the Alarmist mythology (and of course scientific Realists are not given to fictional icons and propaganda). But if Hansen and Gore and company are to be stopped, it’s going to take a message so compelling that the naive media and the gullible politicians (who want so badly to collude in increasing control and taxes—look at Obama’s cabinet!) cannot ignore it.
A few more cold years will help, but the ‘climate change’ movement has gotten so much momentum that it’s going to take much more to stop it. Reputable Realist scientists have got to stand up and denounce the AGW alarmism as a complete hoax. And they have got to do so in dramatic ways, that the media can’t ignore.
One place to start: in the schools. Every time the kids are forced to watch “An Inconvenient Truth,” challenge the school to present the other side, even with a lawsuit if necessary. Nothing gets the press’s attention like a good battle.
/Mr Lynn
hotrod says:
You have misread your own citation. Read what Schneider is actually saying in what you have quoted. The consensus that he is talking about is the consensus regarding the effect of aerosols specifically…i.e., that aerosols cause cooling. He is not talking about any consensus about the future course of climate. And, in fact, as we now understand it, the consensus that aerosols cause cooling is correct…and the “smaller but growing fraction of the current evidence [that] suggests that it may have a warming effect” remained small. (It is understood that soot has a warming effect but the net effect of aerosols is still understood to be that they cause cooling.)
Note also his statement:
This demonstrates that climate science at the time had already more-or-less converged on the explanation that we have today for the early 20th century warming and the mid-20th century (slight) cooling. (Today, I think the scientists would tend to downplay the amount that CO2 contributed to the early 20th century warming, although they think it was a small factor, and some would add solar as an additional explanation for part of the warming in addition to the absence of volcanic activity.)
By the way, here is a book review by Schneider of “The Weather Conspiracy: The Coming of the New Ice Age” in 1977, just a short time after the publication of his own “Genesis Strategy” book, in which he makes it very clear that he thinks that it is still too early to predict the future course of the climate and takes to task the sensationalist popular books appearing on both sides (i.e., “The Weather Conspiracy” and “The Cooling” on one side and “Hot House Earth” on the other side): http://stephenschneider.stanford.edu/Publications/PDF_Papers/Schneider1977.pdf
Richard M:
That is what scientists do…They put up and defend hypotheses. Were there a few scientists who were overzealous in claiming that they knew what the future would hold? Yeah…although it appears to be very few. (For example, Rasool and Schneider is often given as the most dramatic example in the peer-reviewed literature of scientists advocating global cooling; however, if you read their paper…and particularly their response to a comment only 6 months later, it is clear that they accept the fact that their work is very tentative…a first attempt, if you will. And, within a few years, Schneider was even more clearly stating that we could not yet predict the future course of the climate.)
No…You are not supposed to believe that they understand it perfectly. In fact, scientists will readily admit that we may be in for some surprises…and unfortunately some of them could be rather unpleasant! However, that does not mean that they do not understand it at all. And, lack of complete certainty in general does not mean that the best course of action is to do nothing.
I am taking the actual lessons from history that are there rather than just making up ones to suit my biases. And, the actual lessons are that the National Academy of Sciences made the right call back in the 70s, that most of the scientists in the peer-reviewed literature were quite restrained and did not overstate their certainty (a few may have…although I haven’t seen any great examples thus far), and a few popular books and popular news articles got the story wrong.
That is correct! The statement I was answering was your assertion that there was no concensus on cooling period in the literature!
You were completely discounting that there was any consensus on cooling
His comments clearly show that yes there was, but it was undergoing a shift at the time he wrote his book.
It does not matter what the mechanism was, the MSM was properly reporting that the science at the time favored a cooling trend not a warming trend. At the time a debate was in progress regarding what we now call global dimming, and the effect of both low altitude aerosols such as the so called “brown cloud” inversions in the Denver and Los Angeles basins of particulates and the effect of high altitude aerosols specifically the effects of sulfates due to volcanic activity. The cooling effect of volcanic aerosols was supported by after the fact analysis of the Mount Agung eruption in 1963 and of Volcan de Fuego in Guatamala in October of 1974. That cooling effect was finally well documented following the El Chichon eruption in April 1982 where cooling was not only predicted but confirmed following the event. This was also the time period that high altitude effects of the SST and its contrails and exhaust emissions were major points of discussion.
Stephen Schneider
Pg 136
He comments in the book that both effects are active and he guessed at that time that CO2 had about 1/2 the warming effect of the cooling impact of aerosols, but he was concerned that in time CO2 would overwhelm the particulate screening and become the dominant forcing agent.
In that he was sort of correct but for the wrong reason. CO2 increased in relative importance, not because it was a significant factor, but that pollution control efforts drastically cut aerosols and sulfates emissions by cars and industry, and volcanoes were relatively quiet. That focused every ones attention on CO2 and what it hypothetically might do to the climate.
Larry
hotrod: You post starts out saying one thing and ends with another. The point is simply the all the quotes you give from Schneider are answering the question, “What is the consensus regarding what the effect of aerosols / pollutants will be?” He says that it is cooling, which was correct then and is still correct now. They do not appear to be addressing the question, “What is the consensus regarding the future course of the climate when all factors are considered?” (and, indeed, you come around to noting that in your post).
As you note in your last two paragraphs, he clearly noted that there was another separate effect…the warming effect due to greenhouse gases and he correctly speculated that this effect would eventually dominate. As for him being right for the wrong reason: Well, actually, I would say that both reasons are important. Yes, it is important that we started to clean up our act and reduce our emissions of pollutants. However, he is also right about the short-term vs long-term effects: Aerosols pollutants do not remain in the atmosphere a long time, so the concentration of them in the atmosphere is essentially proportional to their current emissions. CO2, by contrast, remains for a long time and hence its concentration is essentially proportional to the cumulative total emissions. Under such a scenario, there can be a tendency for aerosol pollutants to dominate over the short term, but eventually over the long term, the CO2 will tend to dominate unless we continue to exponentially increase our emissions…which I doubt anyone thought we could do indefinitely in the case of pollutants.
And, by the way, I think the reason the MSM tended to be dominated by stories of global cooling was the fact that these stories had more of a “hook” with the fact that we at that time had in fact experienced a cooling trend (although basically just in the northern hemisphere) since mid-century, as the Peterson et al. paper ( http://ams.confex.com/ams/pdfpapers/131047.pdf ) notes. And, as this paper further notes, even this domination wasn’t complete. Alas, people who try to propagate the “global cooling myth” are rather selective in their use of evidence, for example, when the cite the N.Y. Times article written by Sullivan that was titled “Scientists ask why world climate is changing; major cooling may be ahead” in May 1975, but don’t bother to mention the one that he wrote in August titled “Warming trend seen in climate; two articles counter view that cold period is due.” I guess that fact would just confuse their message a little too much!
From ICECAP.US Feb 18, 2009
The US Government War on Coal
‘First let’s fire Dr. Hansen. He is making a mockery of NASA and engaging in behavior that is irrational and quite possibly illegal. Then let’s bury the White House in emails, letters and faxes to say “Lay off coal!”
By Alan Caruba
While President Obama was eagerly signing new legislation to keep unqualified borrowers in their homes by doling out billions of our dollars, over at the Environmental Protection Agency they were leaking plans to use the Clean Air Act as a subterfuge to regulate the second most essential gas, other than oxygen, for all life on planet Earth, carbon dioxide (C02).
Cheering from the sidelines is every demented environmental group in America including the Sierra Club which, if it had its way, would ban the building of a single new coal-fired plant anywhere and shut down the existing ones. This is madness on a scale we have not seen since the mid-point of the last century.
Over at Friends of the Earth, they are breaking out the prayer beads, worried to death that upgrading and improving the nation’s infrastructure means building new roads, bridges and tunnels where they are needed. All the while, the most deceitful President to have ever occupied the Oval Office keeps telling everyone that global warming is real when, in fact, the Earth has been cooling for the past decade. Obama is trying to transform the United States of America into a nation where science means nothing and lies mean everything.
We now have the spectacle of a government employee, Dr. James Hansen, shilling for Capitol Climate Action, saying on a YouTube video that everyone should come to Washington, D.C. on March 2 for what is described as �the largest mass civil disobedience for the climate in U.S. history.� The event is a protest of the Capitol Power Plant that uses – gasp – coal to produce electricity. By the way, that white stuff coming out of the stacks of power plants, including nuclear, is excess steam used to turn the huge turbines that generate electricity. In other words, water vapor.
Dr. Hansen is the Director of the NASA Goddard Institute for Space Studies who lately has been writing to the leaders of the United Kingdom and Europe saying that coal-fired plants are the moral equivalent of the Nazi death camp at Auschwitz during WWII. He�s the fellow who, in 1988, told a congressional committee that global warming was going to destroy the Earth. Al Gore uses him as a footstool.
The immediate question is why someone drawing a government check should also be advocating civil disobedience on behalf of a non-governmental organization or group? The larger question is whether the government is going to make it impossible to provide the growing needs for electricity that all Americans will require by 2030 or sooner? The U.S. has vast deposits of coal with which to generate electricity. To claim that coal is responsible for a global warming that is not occurring and that we must abandon the source of 50% of all the electricity we use every day is insane.
First let�s fire Dr. Hansen. He is making a mockery of NASA and engaging in behavior that is irrational and quite possibly illegal. Then let’s bury the White House in emails, letters and faxes to say “Lay off coal!”
In an astonishing few weeks, the Obama administration has initiated legislation that will further bankrupt the nation, saddle future generations with debt, interfered with the normal action of the housing market, and now wants to leave us without enough electricity to turn on the lights!
If you want to see what Hansen has actually built into his models for aerosols, this is from GISS Model E up to 2003.
http://img175.imageshack.us/img175/6919/modeleaerosolshb4.png
This is the GHG forcing versus all the other forcings (aerosols, volcanoes, solar, land use, and others net) to 2003.
http://img183.imageshack.us/img183/6131/modeleghgvsotherbc9.png
It is just “plug” and play in my mind. The Aerosols forcing does not follow what we really know about aerosol trends and the volcanic forcing is vastly overestimated.
http://img101.imageshack.us/img101/7802/modelevolcanoesmr4.png
I found an interesting book on google that describes the process for measuring CO2 or what they called Carbonic Acid at the time. It was published in 1872 and there are many graphs that show the CO2 levels. Also a discussion of how CO2 levels decreased some at 1,000 feet above the plains and then increased at elevations over 3,000 feet to levels slightly above the plains. They also discuss the monthly differences and the higher levels one January that was warmer than usual. They took measurements in mines and it had earlier been concluded that levels above 7,000 PPM were dangerous. It seems that levels about 350 were considered desirable in the countryside. The also measured inside buildings and found much higher levels of up to 2,000 PPM in some theaters. In Geneva Switzerland levels of 500 PPM were not unusual in the summertime. Spain was found to have a great variation of levels and at sea the levels were higher. All in all an enjoyable diversion. I started reading at page 42.
http://books.google.com/books?id=AuhxAAAAMAAJ&printsec=frontcover&dq=climatology+date:1700-1900&lr=&as_brr=0&as_pt=ALLTYPES#PPP1,M1
Hotrod: “…recent research” was just beginning to make a small faction of “skeptics” contend that it would actually be a warming trend.”
You have enclosed the word “skeptics” in quotation marks, but this word does not appear in the quotation you cite.
Tellingly, the quote also says: “What’s more, a smaller but growing fraction of the current evidence suggests that it may have a warming effect”.
This small “fraction of the current evidence” transmutes in your hands into: “small faction of skeptics”.
It’s clear from the quote that Schneider is canvassing the options with an open mind. Note also that he suggests that increasing concentrations of CO2 could lead to changes in the climate by the end of the 20th century.
Bill Illis:
http://img101.imageshack.us/img101/7802/modelevolcanoesmr4.png
Interesting graph Bill. If Hansen is right, nearly all the warming in the decade 1993-2003 is due to post pinatubo recovery, not GHG’s. 🙂
That is because it is not a quote of Stephen Schneider, his quote extends only to the end of the blockquoted section (indented block) if you are not familiar with the coding commonly used here —
It is a rarely used concept called humor (quote was for emphasis rather than over using bold). I thought it was ironic that at the time he made those comments, He was the skeptic to the prevailing consensus. I could have used a smiley I suppose, but thought the implied satire was so obvious it was unnecessary.
This entire block and the following is my comment not a quote of him!
Absolutely correct, he was obviously already inclined toward the current emphasis on CO2, and he was pointing out that there was conflicting evidence that could be interpreted several ways. Just like today, in the 1970’s there was one dominate “consensus” position and a minority “skeptic” position which at that time was his position. He also used the term deniers in that book as well so that is a long standing label in the climate debate community.
[note in case you missed it, I do not attach any negative connotation to the word skeptic — nor should anyone else — it is simply a word that indicates a researcher is not convinced that the evidence says what everyone else has concluded.]
It is interesting that his skeptical alternate view of the data is accepted as perfectly normal and reasonable scientific behavior, but if someone today voices a similar alternate interpretation to the body of data or chooses to conclude that the body of evidence points a different direction, than the prevailing majority opinion, he/she is instantly vilified as either an idiot or someone who is doing something malicious.
Now maybe we can get back to the topic of this thread which is Hansen’s comment on coal trains of death rather than beating a dead horse.
Larry
Bill Illis (19:09:54) :
If you want to see what Hansen has actually built into his models for aerosols, this is from GISS Model E up to 2003.
http://img175.imageshack.us/img175/6919/modeleaerosolshb4.png
This is the GHG forcing versus all the other forcings (aerosols, volcanoes, solar, land use, and others net) to 2003.
http://img183.imageshack.us/img183/6131/modeleghgvsotherbc9.png
It is just “plug” and play in my mind. The Aerosols forcing does not follow what we really know about aerosol trends and the volcanic forcing is vastly overestimated.
http://img101.imageshack.us/img101/7802/modelevolcanoesmr4.png
Showing the actual failings of Hansens models Bill?
That won’t get replied to in this dialogue of the deaf.
They are here to shout us down and tell us we are stupid.
Keep it coming. 😉
Wondering Aloud (11:01:09) :
Apols for the dealay in responding – I’ve been away on a trip..
There’s quite a lot of science that addresses this point. Some of the early data (but well after your 1991 story!) was described here:
Blunier T, Brook EJ (2001) Timing of millennial-scale climate change in Antarctica and Greenland during the last glacial period. Science 291,109-112.
Abstract: A precise relative chronology for Greenland and West Antarctic paleotemperature is extended to 90,000 years ago, based on correlation of atmospheric methane records from the Greenland Ice Sheet Project 2 and Byrd ice cores. Over this period, the onset of seven major millennial-scale warmings in Antarctica preceded the onset of Greenland warmings by 1500 to 3000 years. In general, Antarctic temperatures increased gradually while Greenland temperatures were decreasing or constant, and the termination of Antarctic warming was apparently coincident with the onset of rapid warming in Greenland. This pattern provides further evidence for the operation of a “bipolar see-saw” in air temperatures and an oceanic teleconnection between the hemispheres on millennial time scales.
A lots of work in the intervening years has pretty much reinforced that conclusion. The Antarctic started warming (due to Milankivitch cycle insolation changes) 17-19,000 years ago….there does seem to be a short lag between Antarctic warming and the onset of CO2 rise as indicated in Antarctic cores. However the onset of warming in Greenland is dated to 15,000ish years ago, and follows the rise in atmospheric CO2. In fact deep S. hemisphre warming and the onset of CO2 rise (likely from the Southern oceans) seems to have preceded post-glacial warming in the tropics too..
L. Stott, et al. (2007) Southern Hemisphere and Deep-Sea Warming Led Deglacial Atmospheric CO2 Rise and Tropical Warming Science 318, 435 – 438
abstract: Establishing what caused Earth’s largest climatic changes in the past requires a precise knowledge of both the forcing and the regional responses. We determined the chronology of high- and low-latitude climate change at the last glacial termination by radiocarbon dating benthic and planktonic foraminiferal stable isotope and magnesium/calcium records from a marine core collected in the western tropical Pacific. Deep-sea temperatures warmed by 2°C between 19 and 17 thousand years before the present (ky B.P.), leading the rise in atmospheric CO2 and tropical–surface-ocean warming by 1000 years. The cause of this deglacial deep-water warming does not lie within the tropics, nor can its early onset between 19 and 17 ky B.P. be attributed to CO2 forcing. Increasing austral-spring insolation combined with sea-ice albedo feedbacks appear to be the key factors responsible for this warming.
And we can determine the atmospheric CO2 response to temperature by observing through several glacial-interglacial cycles that 5-6 oC of global warming/cooling results in a CO2 response near 90 ppm (around 180 ppm glacial to around 270 ppm interglacial). In other words 1 oC of temperature rise is expected to give us around 15 ppm of increased atmospheric CO2. Of course this response in glacial cycles occurred very very slowly (over around 5000 years) and can be considered the CO2 response to temperature at equilibrium. A one degree temperature rise over 100 years (say) will likely give considerably less than this since….
As we are discussing the Hanson file, the Government has arrived to the point of introducing a regulatory “hell”.
http://heliogenic.blogspot.com/2009/02/here-it-comes-regulatory-hell.html
It’s time to swamp the White House with e-mails, letters and faxes.
Another call for action can be found here:
http://sciencepolicy.colorado.edu/prometheus/not-a-peep-from-scientists-4962#comment-12295
“Human beings have never experienced an atmosphere with CO2 levels significantly above what they are today” (Early posts)
Actually, they have and they do. Greenhouse plants are regularly raised in CO2 enriched atmospheres (~1000ppm), which those attending to them and picking the crops experience with no ill effect, or even awareness. The plants like it too.
Graeme Rodaughan (13:26:16) :
“AGW Proponent”???
I don’t think Hansen’s descriptions of potential future consequences depends on a “CO2 tipping point”. The “catastrophic” scenarios relate to massive burning of all fossil fuels (all the oil, natural gas, coal, shale oils etc) that would lead to very high CO2 concentrations indeed. We can get an indication of the sort of world those greenhouse gas levels (e.g. 1500-2000 ppm) would give us, by comparing those levels with periods in the past. So during the Late Cretaceous with those sort of greenhouse gas levels) global temperatures were around 15 oC warmer than now (35-37 oC between 20 o – 30 o N [***]) and the greenhouse forcing was above levels for which glacial ice was possible. So we’d be extremely hot; agricultural production would plummet; sea levels would be destined towards a 200 foot rise….and so on. Pretty catastrophic.
http://www.nature.com/nature/journal/v437/n7063/abs/nature04096.html
This doesn’t really require “tipping points”. However a greatly enhanced greenhouse forcing would lead to positive feedbacks that might be considered non-linear amplifications which could constitute a series of “tipping points” if we chose to call them that…e.g. a rapid positive albedo feedback due to massive ice melt…..a rapid positive feedback due to greenhouse gas release from tundra thaw…..a rapid positive feedback due to tropical forest die-off….a rapid positive feedback when the deep oceans warmed sufficiently to release the methane sequestered in cold clathrates…
Hansen’s other scenarios (e.g. 500-600 ppm CO2-induced long term forcing) relate to sea level rises resulting from committed melting of much of the Greenland ice cap and parts of the West Antarctic ice sheet, reduced agricultural production in the lower latitudes. It’s a semantic point whether one considers these “catastrophic”. They’d certainly be “catastrophic” for some! Most warming scenarios give us strong likelihood of major continuing extinctions…
There’s plenty of evidence for positive feedbacks in the deep past. The paleorecord shows a strong relationship between Earth temperature and atmospheric greenhouse gas levels, anf the warming from enhanced greenhouse gas has inherent positive feedbacks (the water vapour feedback, an albedo feedback especially if there is glacial ice under prevailing conditions.
Notice that it doesn’t require “negative feedbacks” to generate cooling in the past or oscillations in the past (or present). In fact cooling of the Earth is also usually asociated with positive feedbacks. One has to be careful not to apply inapproppriate analogies (e.g. feedbacks in engineering/electronics contexts).
Yes, we hear you!