By John Fleck and William Connolley
To veterans of the Climate Wars, the old 1970s global cooling canard – “How can we believe climate scientists about global warming today when back in the 1970s they told us an ice age was imminent?” – must seem like a never-ending game of Whack-a-mole. One of us (WMC) has devoted years to whacking down the mole (see here, here and here, for example), while the other of us (JF) sees the mole pop up anew in his in box every time he quotes contemporary scientific views regarding climate change in his newspaper stories.
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The problem is that the argument has played out in competing anecdotes, without any comprehensive and rigorous picture of what was really going on in the scientific literature at the time. But if the argument is to have any relevance beyond talking points aimed at winning a debate, such a comprehensive understanding is needed. If, indeed, climate scientists predicted a coming ice age, it is worthwhile to take the next step and understand why they thought this, and what relevance it might have to today’s science-politics-policy discussions about climate change. If, on the other hand, scientists were not really predicting a coming ice age, then the argument needs to be retired.
The two of us, along with Tom Peterson of the National Climatic Data Center, undertook a literature review to try to move beyond the anecdotes and understand what scientists were really saying at the time regarding the various forces shaping climate on time human time scales. The results are currently in press at the Bulletin of the American Meteorological Society, and Doyle Rice has written a nice summary in USA Today, and an extended version based on a presentation made by Tom at the AMS meeting in January is on line.
During the period we analyzed, climate science was very different from what you see today. There was far less integration among the various sub-disciplines that make up the enterprise. Remote sensing, integrated global data collection and modeling were all in their infancy. But our analysis nevertheless showed clear trends in the focus and conclusions the researchers were making. Between 1965 and 1979 we found (see table 1 for details):
- 7 articles predicting cooling
- 44 predicting warming
- 20 that were neutral
In other words, during the 1970s, when some would have you believe scientists were predicting a coming ice age, they were doing no such thing. The dominant view, even then, was that increasing levels of greenhouse gases were likely to dominate any changes we might see in climate on human time scales.
We do not expect that this work will stop the mole from popping its head back up in the future. But we do hope that when it does, this analysis will provide a foundation for a more thoughtful discussion about what climate scientists were and were not saying back in the 1970s.
Update: Full paper available here.
That’s 2, 4, 3, and 5
http://www.skepticalscience.com/climate-change-little-ice-age-medieval-warm-period.htm
http://www.skepticalscience.com/surface-temperature-measurements.htm
http://www.skepticalscience.com/global-warming-scientific-consensus.htm
http://www.skepticalscience.com/climate-models.htm
You could start at the “Start Here” link at the top of the page:
https://www.realclimate.org/index.php/archives/2007/05/start-here/
Re 200. Just follow the links Hank gave you in 201. For the last link, be sure not to miss:
http://www.aip.org/history/climate/index.html
When you have finished, then, on the subject of civility, try rereading what you wrote in 198.
#201 I have read the skepticalscience sites and remain skeptical of AGW. Even the sites cited are full of suppositions as well they should. I don’t disagree with recorded data, yes CO2 levels are higher, yes there seems to be a disconnect from solar radiance and present warming which ‘could be explained’ by GHGs (remember H2O worse than CO2). Yes anybody would prefer to reduce CO2 production, but present solutions are unmanageable and unrealistic. Nuclear energy and breeder reactions (stamped out by Carter et al.) could have prevented many of our current coal power/ natural gas power CO2 emissions. Solar power use to use more energy to produce the cells than they make in their lifetime until ~2005, wind power great but variable and harmful to bird/insect life and ugly and noisy.
My fear is what is happening TODAY on and in the sun. You can’t get warm if the sun is not putting out. ;-) AGW will be a hoped for dream if we return to Maunder Minimum. Talk about mass migrations from flood waters, how about humans moving south to get warm. Canada returning to its frigid past. The US bread basket returning to its tundra, snow covered past.
I believe, as do many Canadian Solar scientists, we can talk about Global Warming all we want and we are not going to change a thing. But we need to know more about the Sun. SOHO is dying with no replacement on deck. The expected return of Solar flare activity has been postponed 2 times. Once more models don’t match reality.
What I would like to know is what affect current CO2 levels will have on global temperatures if we return to a Maunder Minimum. Has anyone run those numbers and come up with a prediction?
#202 I don’t think I was trying to be uncivil, if taken that way I apologize. I am old enough to have been around for all the different theories since the 60’s and remember all the surety they had in those days and the AGW ‘consensus’ sounds so similar. Global climate change happens, we will see if AGW pans out, yes we should conserve fossil fuels, yes we need more nuclear energy and electric cars/vans, high speed mag-lev trains.
I just happen to live in northern hinter lands and Global Warming looks pretty good after this winter! ;-) My Canadian family members are living a winter nightmare, Arctic Ice has returned thicker (granted only one year see this fun article http://www.nationalpost.com/opinion/columnists/story.html?id=332289) and they are praying for spring. Talk in Canadian Scientific circles also concurs with AGW, but they are keeping a watchful eye on the sun.
I guess my main point is without the sun there would be no Global Warming.
effect.
A cold spell, whether from significant vulcanism or the sun, would increase the rate of use of fossil fuel and the rate of change in ocean pH. Even increasing at the current rate of change, it’ll be good for the microbes, very good.
http://www.wanfangdata.com.cn/qikan/periodical.articles/kxtb-e/kxtb2005/0519/051916.htm
http://gsa.confex.com/gsa/2007AM/finalprogram/abstract_127921.htm
Re: #203 T Siefferman:
“Solar power use to use more energy to produce the cells than they make in their lifetime…”
What is your reference for this? The information I have seen concludes the opposite:
http://www.csudh.edu/oliver/smt310-handouts/solarpan/pvpayback.htm
Yes, windmills improperly sited can slice and dice birds. New windmills designs and proper siting cn mitigate this problem. But ugly? That is in the eye of the beholder. I’d rather gaze at a hillside with windmills than cooling towers reminding me of the perils of nuclear power.
“Nuclear energy and breeder reactions (stamped out by Carter et al.) ”
I’m sure you realize that Jimmy Carter did post-graduate work studying nuclear physics and reactor technology. President Carter was not ignorant of the dangers of nuclear power. On April 18, 1977, he outlined his energy policy. Among his many points were:
“If we do not act, then by 1985 we will be using 33 percent more energy than we do today…
“We will feel mounting pressure to plunder the environment. We will have a crash program to build more nuclear plants, strip-mine and burn more coal, and drill more offshore wells than we will need if we begin to conserve now. Inflation will soar, production will go down, people will lose their jobs. Intense competition will build up among nations and among the different regions within our own country.”
If we had listened to President Carter and took his conservation measures to heart, we would be in less of a fix than we are today.
T Siefferman, your posts could be used as a summary of all the fallacies and misinformation flowing around the denialosphere in one place. First, you have completely ignored my point about the differences in timescales of solar minima and the effects of CO2. A solar activity minimum would provide at best temporary respite, and as Hank pointed out could actually exacerbate the crisis in the long term by increasing fossil fuel consumption.
Your tirade against “consensus science” indicates to me that you have zero understanding of science. Do you advocate rejecting the scientific consensus on gravity, evolution, a heliocentric solar system, etc. as well? The best measure of scientific consensus that I know of is the amount of publication going on. When a theory/position becomes so infertile that its advocates cease to publish, then the consensus is against it. Papers that reject anthropogenic causation are rarer than hen’s teeth, and when published produce no follow up.
Ignorance is 100% curable. Hank has vectored you to a good place to start your education. What you do with the pearls is up to you.
#207 Gravity theories have been tested and found to be accurate. A heliocentric solar system was once a theory, tested and later witnessed. So again both proven theories. Still not proven for AGW in my estimation, not an ignorance of the theories, just don’t think they meet the threshold for acceptance. Been a scientist for 25+ years.
Reference on solar cells: http://www.sciencenews.org/articles/20080301/fob5.asp as I said only recently have they become more efficient.
The vectoring was to more theory sites and I am aware of those theories.
Again what would a Maunder minimum (hundreds of years) not a solar minimum do to climate change. It would increase CO2 if we use fossil fuel over nuclear, it would probably decrease H2O vapor and CH4, also GHGs, what does AGW theory predict will happen then…my understanding is that that’s not included in the theory. And that is my fear.
Just because someone doesn’t agree with AGW is not ignorance, just striving for the best theory to explain climate change.
Interesting how Dr Scafetta response was an excellent rebuttal of AGW being the sole cause of GW. https://www.realclimate.org/index.php/archives/2006/03/solar-variability-statistics-vs-physics-2nd-round/
Thomas Siefferman, for a scientist, you are awfully cavalier with facts. See this reference for info on the Maunder Minimum:
http://en.wikipedia.org/wiki/Maunder_Minimum
Note the duration of ~75 years.
More generally, see Usoskin’s recent paper “Grand minima and maxima of solar activity: new observational constraints”. Solar variability is a blip compared to what CO2 will do long term.
Thomas Siefferman, how do you explain the cooling stratosphere, in spite of the warming surface temperatures?
Also, Carl Sagan reported that the climate models being used to understand AGW could accurately model climates on other planets. He had confidence in those models. Your criticism of the climate models seems to me to be along the lines of: “If you cannot predict the climate on the 13th of January 4172 BC at 12:45 pm then the models are rubbish! Can you quantify your problems with the models? Which models?
Re #204
“Arctic Ice has returned thicker (granted only one year see this fun article http://www.nationalpost.com/opinion/columnists/story.html?id=332289) and they are praying for spring. ”
As a scientist I would have expected a more authoritative source than that!
Here’s some genuine information on the ice thickness rather than local cherry-picked anecdotes:
http://www.nsidc.org/images/arcticseaicenews/200804_Figure4.png
http://www.nsidc.org/images/arcticseaicenews/200804_Figure6.png
And another on NH snow thickness for March showing near record lows!
http://climate.rutgers.edu/snowcover/chart_anom.php?ui_set=1&ui_region=nhland&ui_month=3
“I guess my main point is without the sun there would be no Global Warming.”
Wow, some real insight there!
I’m glad everyone has lightened up! :-) Nice to see discussion not put downs. The National Post article was not meant as scholarly work, just fun to see how quickly the Press confuse Climate Change Prediction with weather forecasting. The Ice thickness reduction is to be expected with any global warming, just like occurred in the Medieval Warm Period, (there still people up nord here who believe that’s how the Vikings made it to Minnesota ;-) ). Any scholar frowns upon Wikipedia so I don’t use that as a source, agreed Maunder Minimum is thought to have begun 1645 to 1715, however there was a prolonged period of minimal sunspot activity thought to have begun as earlier than 1600 and not rebounding to more conventional solar flare activity till 1730, but all of these numbers are really just speculation. I guess the confusion is I was overlapping thoughts/concerns between the ‘Little Ice age’ and the Maunder Minimum which occurred in the middle.
Until we enter the ‘Gore Minimum’ as some of my joking solar scientist friends call it, we just really won’t know what will happen. We have been blessed to have grown up in an interglacial age with pretty regular solar variation but the 200year cycle is upon us.
As to my problems with retro-forecasting the past, I would like to see current AGW proponents show us what temperature patterns we would have expected say in 1600-1750, or 800-1300 or 1930-1980, pick your range. I just haven’t seen it done with the accuracy they would make me want to severely curtail my current economic system.
Scafetta’s article does agree with AGW if it would include more of a solar effect. Again my fear is not that AGW theories are right or wrong, rather that they be the most accurate they can be. THAT is the role of a scientist, not always accepting the current theory but to tweak it, improve it, throw it out and redo it, and I just don’t see enough of it. Consensus too often leads to intellectual laziness. That is what I stress to my students.
#212, you would think that was heresy to think the sun might affect climate in some AGW camps. If AGW theories can’t be assistance in a global emergency like a Maunder Minimum, then I am afraid all the hard work on Climate Modeling will be for naught; non-scientists will throw the baby out with the bathwater! Please remain civil now when you tear my comments apart. :-0
An easier to view Arctic Ice diagram is
http://nsidc.org/data/seaice_index/images/daily_images/N_timeseries.png
Thomas Siefferman,
First, Wikipedia is as accurate as any other encyclopedia when it comes to science. See:
http://www.nature.com/nature/journal/v438/n7070/full/438900a.html
The key wrt Wikis is that if a subject is popular, errors are more likely to be discovered quickly, while if it is obscure, they tend to persist.
In any case, I also referenced Usoskin et al. I presume you have no problem with the credentials of those authors. And my point still stands–solar activity minima persis on a scale of decades, while the effects of CO2 last for centuries.
As to the current “minimum,” I don’t know any solar scientists who are concerned just yet. We are still not really outside the norm for a solar cycle.
I do fear that you are right about one thing: If there is a respite in the warming, the great unwashed will assume the crisis is over and that they can go on consuming as before. In actuality, this would be disastrous. Climate change could give the edge to renewable energy technologies and provide an impetus to really develop sustainable economies, whereas if “the heat is off” we can count on the 21st century being the century of coal, and the 22nd as being the century where civilization ends.
T. Siefferman writes:
What 200-year cycle?
There are several cycles the sun goes through, the 11 year solar max to min, the 22 year reversal of magnetic field, due to the solar ‘conveyor belt’ http://science.nasa.gov/headlines/y2006/10may_longrange.htm
It has been speculated that on an approximate 200 year cycle, not only do we get a reversal of magnetic activity, but such a dramatic slowing of this conveyor mechanism that we get a prolonged pause, this has been shown to lessened solar flares and hence irradiance. Originally this was ‘not suppose to occur till after Solar Cycle 25 around 2022’. What has people worried is it’s taking longer for Cycle 24 to get started and the conveyor has stopped early, so maybe the 200 year cycle is here early.
[Response: Then it’s not a cycle. – gavin]
Gavin, when you run ModelE in the “forecast mode” do you assume
a constant TSI ( as in average of the past) or do you feed the model a
nominal 11 year cycle?
By the way thanks for the link to the modelE results.
[Response: http://data.giss.nasa.gov/modelforce/solar.irradiance/ – gavin]
{Response to 217} In solar cycles the ‘solar conveyor 200 year cycle’ is a theory being promulgated to explain the appearance of prolonged solar minimums than seem to occur on a 180-220 year stretch. I’d love to hear a theory as to why it occurs, but is has been noted to occur on similar stars as it does on Sol. One of many problems is some in the solar physicists gang believed that Solar Cycle 24 would have already started because of this conveyor belt slowing, and were speculating that Cycle 24 would reach a higher maximum than even 23 (more fuel for global warming). In contrast another group believes the slowing of the conveyor in this period is occurring too fast and will lead to a Gore Minimum (I couldn’t help myself ;-) ). So just like in AGW vs GW Climate prediction circles, theories have been advanced and we will see who is right. I personally am praying for Solar Flares every day as I live in the friggin’ tundra where is was 65F today and suppose to snow Sunday!
Just another “Minnesotan For Global Warming”…well at least up here.
It appears we have solar cycle 24.
Please see:
… and:
With regard to claims of solar cycles greater than 11 years in length (200 years, 22 years, etc.), the following post might be worth reading:
We had one sunspot in correct polarity in January 8 and one very small one in April 14 (gone in a day+, visible only with magnetometer, not visual) and still 12 Solar Cycle 23 spots. The concern again is the slowness of return of solar flares (should have had 16 of Solar 24) their minimal nature, and every one keeps changing when and how the flares will return.
The ‘200 year cycle’ I was referring is related to the slowing to a crawl of the solar conveyor (since the Jose cycles were incorrect) and it was forwarded to explain the same periodicity of Oort, Sporer, Maunder and Dalton minimums. Unfortunately, humans always try to find cycles in random events, check http://en.wikipedia.org/wiki/Image:Carbon14_with_activity_labels.svg
I found the ‘correct name’ for the 200 year cycle is Suess or De Vries Cycle.
Considering that we only have accurate observational data going back about 400 years, and the mid-to-late 1600’s and early 1800’s were both periods of minimal activity, we won’t know if there is actually some 200 +/- cycle for a while. What we could be seeing is a return to normally less active cycles as the last few have been above average in activity anyway.
It’s undeniable that the last 5 cycles have been above average. So, it’s not clear that this is the start of the Gore Minimum, or a return to more normal values.
(And I’m going to start referring to the delay in cycle 24 starting as the “Gore Minimum” ;) )
“Failure to Warm” — (here)
This is a worst-case scenario I’ve discussed before — solar activity dominates climate change, a decline in solar activity results in a short term cooling. From there, skepticism builds, CO2 reductions stall, sun returns to higher levels of solar activity, even more rapid warming down the road.
If cycles 24, 25 and ??? are less active, the next 20+ years of cooling will lead to continued high levels of carbon-based resources and no decline in rate of increase in CO2 levels. When we exit the “Gore Minimum” in another 25 or 35 years, CO2 levels will be much higher, but instead of having sufficient resources to make the transition, we’ll be stuck in a carbon-based death-spiral as we consume all the fancy coal-to-something-else fuels we can in order to shift off of carbon-based resources.
Comments?
The Australian is at it again — publishing a claim that 2007 was 0.7°C cooler than 2006 and shock! Horror! We are heading into an ice age. Then repeating the claim in another op ed after it was thoroughly debunked.
See my blog for detailed comments.
For those worrying about recent months being cooler than average and thus harbingers of (solar cooling) doom, don’t worry. March is back up among the record highs. See the GISS 2007 global temperature summation for some numbers on solar effects on climate.
“Those 7 articles predicting cooling apparently inspired at least 2 films that I remember being shown in Junior High School.”
And…
“Browsing though file from my youth I cam across a junior-high school paper I was made to write in the early 1980’s. The premis given to the class was that industrial pollution might lead to another ice age, and we were supposed to describe how this might affect mankind. … Does anyone else here have school age memories about cooling vs warming?”
The hype du jour in my timeframe was the Sagan nuclear winter hypothesis.
It’s clear based on the comments that there were in fact books, news storeis and popular treatments on the ‘coming ice age’ (eg, also a BBC show in 1974). We have 3 vectors: Real science, popularization of science in the media, and what is told to children.
It should not surprise us that real science is more responsible, balanced and less prone to hype and unwarranted conclusions than popular media of
Current the educational indoctrination action du jour is to subject schoolchildren to Al Gore’s AIT film. While his film’s viewpoint is supported here, but let me make point out that its got its share of dangerous simplification. Eg: Any responsible climate scientist should cringe when Al Gore in AIT points to Antartica and said “*If* this ice goes away”, sea levels will rise 20 feet. Nice if-based escape clause, but that’s preying on fears. Antartica’s ice is not decreasing and IPCC has made clear that it would take well over 10C heating in the antarctic to make that happen. It wont happen. Al didnt say how impossible it would be to make it go away. Its been there for millions of years, during periods when earth was much warmer, and will remain there even under extreme conditions. When you subject a grade-schooler to this, they pick up on the inflection “Oh, the south pole is melting” and not the caveats.
Popular treatments/media and simplified explanations for schools take out the caveats and uncertainties. Thus they are more prone to irresponsibly creating incorrect impressions. Those treatments are what gets impressed on people’s minds, not the science.
If the claim in dispute is that there was a scientific consensus about global cooling, its been put to rest here (but I havent heard that claim).
If the claim was that there was media hype about a coming ice age in the 1970s, there was indeed some such hype.
And in any case, isn’t a future ice age somewhat predictably expected, in say 5,000- 15,000 years, given the last million years of climate cycling (viz thread comments on drivers of Ice Ages)?
So isnt the real story here one of taking a mundane truth (“a future ice age is likely in many thousands of years”) into a hyped-up fear (“we are all going to freeze!”) for the sake of selling readers/viewers?
“Thomas Siefferman, how do you explain the cooling stratosphere, in spite of the warming surface temperatures?”
What cooling stratosphere? Cooling from 1980 to 1995 but TLS seems to have flattened out since the mid 1990s:
http://www.ssmi.com/msu/msu_data_description.html#msu_amsu_trend_map_tls
[Response: These stratospheric trends: http://acd.ucar.edu/~randel/2007GL032218.pdf (Note that MSU4/TLS is responding mostly to ozone depletion so you expect it to be plateauing). – gavin]
Re: 226 A. Nony Mouse Says:
“Any responsible climate scientist should cringe when Al Gore in AIT points to Antartica and said “*If* this ice goes away”, sea levels will rise 20 feet. Nice if-based escape clause, but that’s preying on fears. Antartica’s ice is not decreasing and IPCC has made clear that it would take well over 10C heating in the antarctic to make that happen. It wont happen. Al didnt say how impossible it would be to make it go away. Its been there for millions of years, during periods when earth was much warmer, and will remain there even under extreme conditions.”
Ice sheets in Antarctica have melted in warmer times, and sea level has been higher:
“Sea levels during several previous interglacial were about 3 to as much as 20 meters higher than current sea level. The evidence comes from two different but complementary types of studies. One line of evidence is provided by old shoreline features (figure. 3). Wave-cut terraces and beach deposits from regions as separate as the Caribbean and the North Slope of Alaska suggest higher sea levels during past interglacial times. A second line of evidence comes from sediments cored from below the existing Greenland and West Antarctic ice sheets. The fossils and chemical signals in the sediment cores indicate that both major ice sheets were greatly reduced from their current size or even completely melted one or more times in the recent geologic past.”
http://abdulazeem.wordpress.com/2006/11/03/consequences-of-polar-ice-melting-rising-sea-levels/
Gavin, Thx. Figure 4 of the Shine et al paper shows the observed stratosphere cooling trend from 1979-1997, but no 1995-present trend is shown. Is your comment wrt ozone depletion confirming that stratosphere temperatures have plateau’d since the mid 1990s?
[Response: No. Lower strat temperatures are mostly controlled by ozone depletion which has plateaued. Mid strat and higher (up to the mesosphere) temperatures are still cooling. – gavin]
In regard to:
Rando Says:
18 April 2008 at 12:51 PM
Re: Jim Bullis
Not that the topic of SST impact on storm charactistics and resulting feedbacks isn’t interesting, I believe the original post was in response to observed (percieved?) cooling in the 1970’s that gets referenced by some as evidence of dominant non-anthropogenic (or at least poorly understood) climate influences.
I respond:
Rando
The post discusses anecdotes and what scientists said in the 1970’s regarding cooling or warming in the 1970’s, as you say, however I am more interested in whether or not there is an underlying physical process that would slow the changes in temperature due to GHG effects. And thus, make it more difficult to get a clear measurement.
Warmer surface temperatures do cause increased storm activity. The effect of increased storm activity is to increase vertical mixing of ocean water. Vertical mixing will cool the ocean surface and this will cool the atmosphere. The effect of GHG should be looked for in the changes in deep ocean temperature gradients. This should also be part of the climate modeling programs. It does not seem to be. Although it seems to be a factor considered in the thermohaline circulation modeling, there seems to be a more direct link to the surface temperature that is missing.
> This should also be part of the climate modeling programs.
> It does not seem to be.
How did you come to that belief? Did you look for yourself, or are you relying on some source for it? Why do you trust your source?
http://www.google.com/search?q=%22climate+model%22+deep+ocean+temperature
RE 231, Hank Roberts,
Yes, I looked at the modeling programs in as much depth as I could, though this was limited to looking at the inputs and the data fields listed. This was in a description available on the Internet for the model used by the Boulder, Los Alamos people, as I recall. I also noted a statement that the “Parallel Ocean Program” was not significantly coupled to the main model. I also noted an instruction for running this main model that it was appropriate to “tweak” it to get alignment with past climate data. This gives some credence to the “curve fitting” assessment by Lindzen.
I also got answers here at Real Climate saying the process I describe is accounted for as part of the thermohaline circulation calculations. It is my own experience and knowledge of vertical mixing effects on underwater sound propagation that suggests that the vertical mixing is much more powerful on a local basis, and as such is not adequately represented in the thermohaline circulation.
I trust the Real Climate group for honest answers. I have found it takes some dialog to get to the bottom of things. I appreciate the Real Climate resource for making this possible.
Thanks for the link. I have not plowed through all of what it turns up, but the first reference describes an analysis that does not account for wind driven mixing. The second references turns up a paper by Lindzen that indeed reports deep ocean warming. This, according to me, and maybe even Lindzen ( I have more to read), supports the idea that surface temperatures lag the trends predicted by the models due to the fact that there is an enormous reservoir of cold water that must be accounted for, and that may slow some of the global warming effects.
I also looked at the thermohaline current discussion by the Berlin scientist, where then Atlantic Gulf Stream was discussed relative to the thermohaline currents. He said as I recall, the Gulf steam was only 30% driven by the thermohaline circulation forces, and the rest was wind driven.
Thus, the response here at Real Climate, that the deep ocean cold water effects were coupled through the thermohaline circulation effects, seems to suggest that a lot of ocean dynamic effects are yet to be factored into the modeling predictions.
And yes, I am not just imagining things. It has been some time since I was directly involved with underwater sound research with equipment at 2000 meters in the Atlantic, but I recall there was actual damage to such equipment as the result of hurricanes. It is only through oil company reports, but I fully believe it to be true that significant damages of deep water equipment at similar depths were incurred in the gulf as a result of Katrina.
I hope no one thinks I am suggesting that global warming is not a serious problem. At most, I might be thinking that the ramifications could play out a little differently than some seem to be saying. I do not take lightly the idea that the deeper ocean would be warming to soak up heat due to our excessive use of energy. This will come to haunt us in ways not yet fully realized. Neither is it particularly attractive to think there would be an ongoing need for storms to cause the mixing to keep happening.
Re my last 232
The damage I spoke of had to have been related to proximity to land since waves in the deep ocean do not cause water motion that deep. Checking on this, I find that strong hurricanes in the open ocean could mix water down to about 300 meters. The mixing that could occur due to land proximity would not be as general, but it could still cause some vertical mixing.
But ignoring land effects, open ocean water is generally about 8 to 10 degrees C at 300 meters. This is still cold enough to slow things down for a while since over 90% of the world’s oceans are this deep or greater.
> damages of deep water equipment at similar depths were
> incurred in the gulf as a result of Katrina.
“… mud slides, especially during and after strong hurricanes that cause extreme currents.”
http://news.mst.edu/research/2005/dunnnorman0905.html
Re 234, and 130-233
Thanks for the link. The extremely strong currents are not as deep as I had thought, and seem to be limited to proximity to land. However, it remains a meaningful question as to how far such currents extend to much deeper water as they dissipate.
However, I am now thinking that the above mentioned land proximity processes are not the main issue.
That main issue is vertical mixing due to the long wavelength, very large waves in hurricanes and lesser storms. These waves produce circular currents down to depths approximating their wavelengths. Very powerful hurricanes have reportedly generated wavelengths over 300 meters. The circular currents move in relatively small circles so as to move and mix water vertically. This 300 meters is large enough to be quite important in moving cold water upwards. I will look for a reference on this.
Between 1965 and 1979 we found (see table 1 for details):
* 7 articles predicting cooling
* 44 predicting warming
* 20 that were neutral
Do we know what is the current ratio of articles is?
Today in Climatology class our prof read us passages from “The Deniers” that summarized the consensus scientific view of global cooling in the 1970s, complete with quotes from Bryson and Fairbridge. Thanks for providing some balance. As a conscientious student, I appreciate this resource for fact-checking the one-sided argument presented in class.
Next week we learn that the effect of human influence on climate change is minimal, and that if enhanced greenhouse forcing is occurring, the results of it are relatively benign.
I didn’t read all of the comments, but I read enough. I like the responses to the statement made on scientific curricula of the 70’s; it being something along the lines of produce a text book that taught the coming ice age or it doesn’t exist. Fact is, I was taught that for years -and we had fearful class discussions of the impact on mankind by the coming ice age. The texts taught it, and the science teachers banged on the mantra. If you refute this with “produce a text book” you are 1. not old enough to have attended school in the 70’s, 2. you sklept during science class, were out those two weeks, or you were in remedial eduction classes, 3. you are being dishonest.
The coming ice age was taught in American class rooms as fact in the 70’s, just as AGW is taught today. Produce a text book? Laughable.
[Response: What’s funny is that no-one has produced one. Not one! Are there no teachers still alive that taught it? Or libraries? Or second-hand bookstores? What’s even funnier is that you seem to think we should just take you at your word that these ‘books’ existed, and not only existed, but were used everywhere, and yet no-one can remember the title, the authors, the publishers or the text. Not terribly convincing, I’m afraid. PS. I was in school in the 1970’s and I don’t remember any such thing. – gavin]
Re 238,
And everyone from my generation distinctly remembers being at Woodstock, including the 99.99% of us who weren’t there.
Harcourt Brace
http://www.harcourt.com/bu_info/harcourt_school.html
Ask for an old edition
[edit]
[Response: Of what? – gavin]
Re 238–I wasn’t taught any such thing in the 70s either. You can, however, get around memory issues by Googling the contemporaneous NAS statement on the subject, which says there is no basis to conclude that global cooling was imminent.
Re 239–My understanding was that *only* those not there, remember being there. ;)
It’s quite simple Gavin, all you have to to is go to the library and ask “Can I have a copy of an old book that john read that tells us that the world was going to freeze”.
And then the librarian will tell you “I’m afraid we don’t have that in stock sir” and then YOU say “Can you please order it for me, then. Thanks”.
Then she’ll say “Certainly sir.”
That’s how you get an old copy.
Oh, spilgard, did you have to go and make me spit my tea all over my display?
Maybe john was there and didn’t listen to the warning about not dropping the brown acid.