The Coming Ice Age

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POTUS
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The Coming Ice Age
Quote:

....Today we are again at the peak, and near to the end, of a warm interglacial, and the earth is now due to enter the next Ice Age. If we are lucky, we may have a few years to prepare for it. The Ice Age will return, as it always has, in its regular and natural cycle, with or without any influence from the effects of AGW....

Short but compelling essay at the link below


http://english.pravda.ru/print/science/earth/106922-earth_ice_age-0

Damnthematrix's picture
Damnthematrix
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Re: The Coming Ice Age

EXCEPT we have changed things so much, why should anyone believe the future will be like the past?

Mike 

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Brainless
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Re: The Coming Ice Age

Because plankton and bacteria even have more influence than humans. And humans use models that are flawed.

A flawed model that costs me tax, unable to sell my house for a decent price and i suddenly have a carbon footprint. 

Biggest hoax of all time as only data from very recent is used and data that is not helping the co2 theory is left out. But i know the argument of both sides and it is something that people never agree on. We'll just wait and see, but in the mean time, because it is not proven can i have my tax back, and can my house be appraised again, and am i allowed to breath and exhale co2.

 

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Damnthematrix
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The global cooling myth

The global cooling myth

Filed under:

— william @ 5:31 AM - (Français) (English)

Every
now and again, the myth that "we shouldn't believe global warming
predictions now, because in the 1970's they were predicting an ice age
and/or cooling" surfaces. Recently, George Will mentioned it in his
column (see Will-full ignorance) and the egregious Crichton manages to say "in the 1970's all the climate scientists believed an ice age was coming" (see Michael Crichton’s State of Confusion ). You can find it in various other places too [here, mildly here,
etc]. But its not an argument used by respectable and knowledgeable
skeptics, because it crumbles under analysis. That doesn't stop it
repeatedly cropping up in newsgroups though.

 

I should clarify that I'm talking about predictions in the scientific press. There were some regrettable things published in the popular press (e.g. Newsweek; though National Geographic
did better). But we're only responsible for the scientific press. If
you want to look at an analysis of various papers that mention the
subject, then try http://www.wmconnolley.org.uk/sci/iceage/.

Where does the
myth come from? Naturally enough, there is a kernel of truth behind it
all. Firstly, there was a trend of cooling from the 40's to the 70's
(although that needs to be qualified, as hemispheric or global
temperature datasets were only just beginning to be assembled then).
But people were well aware that extrapolating such a short trend was a
mistake (
Mason, 1976)
. Secondly, it was becoming clear that ice ages followed a regular
pattern and that interglacials (such as we are now in) were much
shorter that the full glacial periods in between. Somehow this seems to
have morphed (perhaps more in the popular mind than elsewhere) into the
idea that the next ice age was predicatable and imminent.
Thirdly, there were concerns about the relative magnitudes of aerosol
forcing (cooling) and CO2 forcing (warming), although this latter
strand seems to have been short lived.

The state of the science at the time (say, the mid 1970's), based on
reading the papers is, in summary: "…we do not have a good quantitative
understanding of our climate machine and what determines its course.
Without the fundamental understanding, it does not seem possible to
predict climate…" (which is taken directly from NAS, 1975).
In a bit more detail, people were aware of various forcing mechanisms -
the ice age cycle; CO2 warming; aerosol cooling - but didn't know which
would be dominant in the near future. By the end of the 1970's, though,
it had become clear that CO2 warming would probably be dominant; that
conclusion has subsequently strengthened.

George Will asserts that Science magazine (Dec. 10, 1976) warned about "extensive Northern Hemisphere glaciation.". The quote is from Hays et al. But the quote is taken grossly out of context. Here, in full, is the small section dealing with prediction:

Future climate. Having presented evidence that major changes in past
climate were associated with variations in the geometry of the earth's
orbit, we should be able to predict the trend of future climate. Such
forecasts must be qualified in two ways. First, they apply only to the
natural component of future climatic trends - and not to anthropogenic
effects such as those due to the burning of fossil fuels. Second, they
describe only the long-term trends, because they are linked to orbital
variations with periods of 20,000 years and longer. Climatic
oscillations at higher frequencies are not predicted.

One approach to forecasting the natural long-term climate trend
is to estimate the time constants of response necessary to explain the
observed phase relationships between orbital variation and climatic
change, and then to use those time constants in the exponential-response
model. When such a model is applied to Vernekar's (39) astronomical
projections, the results indicate that the long-term trend over the
next 20,000 years is towards extensive Northern Hemisphere glaciation
and cooler climate (80).

The point about timescales is worth noticing: predicting an ice age
(even in the absence of human forcing) is almost impossible within a
timescale that you could call "imminent" (perhaps a century: comparable
to the scales typically used in global warming projections) because ice
ages are slow, when caused by orbital forcing type mechanisms.

Will also quotes "a full-blown 10,000-year ice age" (Science, March 1, 1975). The quote is accurate, but the source isn't. The piece isn't
from "Science"; it's from "Science News". There is a major difference:
Science is (jointly with Nature) the most prestigous journal for
natural science; Science News is not a peer-reviewed journal at all,
though it is still respectable. In this case, its process went a bit
wrong: the desire for a good story overwhelmed its reading of the NAS
report which was presumably too boring to present directly.

The Hays paper above is the most notable example of the "ice age"
strand. Indeed, its a very important paper in the history of climate,
linking observed cycles in ocean sediment cores to orbital forcing
periodicities. Of the other strand, aerosol cooling, Rasool and
Schneider, Science, July 1971, p 138, "Atmospheric Carbon Dioxide and Aerosols: Effects of Large Increases on Global Climate" is the best exemplar. This contains the quote that quadrupling aerosols could
decrease the mean surface temperature (of Earth) by as much as 3.5
degrees K. If sustained over a period of several years, such a
temperature decrease could be sufficient to trigger an ice age!
. But even this paper qualifies its predictions (whether or not aerosols would so increase was unknown) and speculates that nuclear power may have largely replaced fossil fuels as a means of energy production
(thereby, presumably, removing the aerosol problem). There are,
incidentally, other scientific problems with the paper: notably that
the model used was only suitable for small perturbations but the
results are for rather large perturbations; and that the estimate of
CO2 sensitivity was too low by a factor of about 3.

Probably the best summary of the time was the 1975 NAS/NRC report.
This is a serious sober assessment of what was known at the time, and
their conclusion was that they didn't know enough to make predictions.
From the "Summary of principal conclusions and recommendations", we find that they said we should:

  1. Establish National climatic research program
  2. Establish Climatic data analysis program, and new facilities, and studies of impact of climate on man
  3. Develope Climatic index monitoring program
  4. Establish Climatic modelling and applications program, and exploration of possible future climates using coupled GCMs
  5. Adoption and development of International climatic research program
  6. Development of International Palaeoclimatic data network

Which is to say, they recommended more research, not action. Which
was entirely appropriate to the state of the science at the time. In
the last 30 years, of course, enormous progress has been made in the
field of climate science.

Most of this post has been about the science of 30 years ago. From
the point of view of todays science, and with extra data available:

  1. The cooling trend from the 40's to the 70's now looks more like a slight interruption of an upward trend (e.g. here).
    It turns out that the northern hemisphere cooling was larger than the
    southern (consistent with the nowadays accepted interpreation that the
    cooling was largely caused by sulphate aerosols); at first, only NH
    records were available.
  2. Sulphate aerosols have not increased as much as once feared (partly
    through efforts to combat acid rain); CO2 forcing is greater. Indeed
    IPCC projections of future temperature inceases went up from the 1995
    SAR to the 2001 TAR because estimates of future sulphate aerosol levels
    were lowered (SPM).
  3. Interpretations of future changes in the Earth's orbit have
    changed somewhat. It now seems likely (Loutre and Berger, Climatic
    Change, 46: (1-2) 61-90 2000) that the current interglacial, based
    purely on natural forcing, would last for an exceptionally long time:
    perhaps 50,000 years.

Finally, its clear that there were concerns, perhaps quite
strong, in the minds of a number of scientists of the time. And yet,
the papers of the time present a clear consensus that future climate
change could not be predicted with the knowledge then available.
Apparently, the peer review and editing process involved in scientific
publication was sufficient to provide a sober view. This episode shows
the scientific press in a very good light; and a clear contrast to the
lack of any such process in the popular press, then and now.

Further Reading:

Imbrie & Imbrie "Ice Ages: solving the mystery" (1979) is an
interesting general book on the discovery of the ice ages and their
mechanisms; chapter 16 deals with "The coming ice age".

Spencer Weart's History of Global Warming has a chapter on Past Cycles: Ice Age Speculations.

An analysis of various papers that mention the subject is at www.wmconnolley.org.uk/sci/iceage/.



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Damnthematrix
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Re: The Coming Ice Age

If I were you, I'd be far more concerned about the amount of money going to fighting wars than the tiny amount that goes to funding climate research.......

Now can I have MY taxes back?

Mike 

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Dogs_In_A_Pile
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Re: The Coming Ice Age

I'm going with Occam's Razor on this one.

The scientific and academic community is at odds over global warming/cooling/somethinging.  That in and of itself is all I need to know - that I don't know what they don't know.  Something is happening and when it does we will know it.

So why do the mouth foamers get all the press?  Self proclaimed "experts" like Sean Penn rant and rave on television that Katrina was caused by global warming that was caused by the Bush Admnistration's environmental policies (or lack thereof) or our refusal to adopt the Kyoto Accords or whatever environmental cause du jour you want to throw in with.  That resonates well with the Hollywood Babylon crowd and the media hostage to celebrity, but has a half-life in the scientific community comparable to a fart in a Force 9 gale.

Anecdotal evidence serves whatever master spins the data the best and wraps it up for presentation in the coolest looking package.

Sorry, now I am venting and the room temp has gone up .04 degrees - I don't want to be accused of initiating the Butterfly effect that leads to the next gamma ray burst that causes the next Indonesian tsunami......

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Damnthematrix
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Re: The Coming Ice Age

Thing is DIAP, we're not arguing about whether cream pies should have sugar or honey in them...  we're arguing about whether we should take seriously the future of civilisation.

Remember the CC's chapter 20?  Where you draw 4 boxes labeled something like 'good' and 'bad' in one direction, and 'ready'  and 'not ready' in the other?  Well now, just apply it to GW.

If nothing happens, but we're ready for it, what's the worst that could happen?  We weaned ourselves off Fossil Fuels (FFs) and we now have a cleaner planet with lots of people employed screwing solar panels to people's roofs.

If nothing happens and we're not ready for it......  well we were just lucky.

BUT....

IF the planet fries, AND we're ready for it, what's the worst that can happen?  We acted in time!

IF the planet fries, AND we're not ready for it, well, we're toast....  literally.

So just what is wrong with assuming the worst?

You say " The scientific and academic community is at odds over global warming/cooling/somethinging."  WRONG.  They just can't agree about how bad it might get, or how quickly.

As far as I'm concerned, just the fact the oceans are acidifying is enough to do something....  not to mention the fact all the FFs are running out anyway, so we should do something about THAT.

I don't particularly want my kids' generation to say in a few years time "those baby boomers were useless so and so's, look at the mess they've left us in..."   I really can't believe anyone's prepared to dice with such a potentially dire issue....

Mike 

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