Richard Lindzen's Lecture: Feedbacks

[kiwistonewall]

I think this is a youtube version of same lecture (can someone confirm) - I couldn't view the first link on this thread

www.youtube.com/watch?v=-sHg3ZztDAw

[Pooh]

Mar 20, 2010 4:45:04 GMT kiwistonewall said:

I think this is a youtube version of same lecture (can someone confirm)

Looks like it. Same person, same title, same date, same scientific integrity.

PDF here:
Lindzen, Richard S. “Deconstructing Global Warming.” Powerpoint (PDF) presented at the Cooler Heads Coalition, CEI, October 26, 2009. wwwglobalwarming.org/wp-content/uploads/2009/10/lindzen-talk-pdf.pdf..

[william]

This is a link to the lecture which Lindzen presented concerning the peculiar issue of global warming.

This is the only issue were if you present data that does not support a specific position that you are called a denier. AWG is a religious belief as opposed to a scientific theory which may or may not be correct.

The Peculiar Issue of Global Warming

vmsstreamer1.fnal.gov/VMS_Site_03/Lectures/Colloquium/100210Lindzen/f.htm#

[william]

This is a better series of lectures by Dr. Carter.

The Aussies call a spade a spade.

www.youtube.com/watch?v=FOLkze-9GcI&feature=channel


www.youtube.com/watch?v=vN06JSi-SW8&feature=channel



www.youtube.com/watch?v=iCXDISLXTaY&feature=channel

[kiwistonewall]

The Aussies call a spade a spade.

No, the Aussies use much more colourful descriptions! ;D

[poitsplace]

I've seen the lectures. I remain unconvinced. I think the climate is FAR more difficult to nail down...and exhibits a random walk + forcings sort of behavior. The Maunder minimum most likely contributed to the LIA but didn't cause it. Minor milankovitch cycle changes contribute to fluctuations. CO2 contributes what I believe to be undetectable forcing...but I'm willing to entertain the notion of REASONABLE forcings (maybe 1C for a doubling).

[william]

I've seen the lectures. I remain unconvinced. I think the climate is FAR more difficult to nail down...and exhibits a random walk + forcings sort of behavior. The Maunder minimum most likely contributed to the LIA but didn't cause it. Minor milankovitch cycle changes contribute to fluctuations. CO2 contributes what I believe to be undetectable forcing...but I'm willing to entertain the notion of REASONABLE forcings (maybe 1C for a doubling).

Hi Poitsplace,
If planetary feedback is negative then the planet resists changes to planetary temperature by increasing or decreasing planetary clouds.

As Carter shows in his lecture the ice sheet analysis shows that there has been very large cyclic planetary temperature changes. (Glacial/interglacial cycle for example. Interglacial period starts abruptly, lasts around 10,000 years and ends abruptly. Why?)

A large powerful cyclic forcing mechanism is required to explain what is observed.

There is an urban legend that very large cyclic planetary climate changes can occur due to some mysterious random walk. The observational evidence does not support that hypothesis. There is clear indication of small, medium, large, and super large external forcing in the paleoclimatic record.

Recently it has been found that there are geomagnetic field excursions that occur at the same time as the super large abrupt climate changes. (The Younger Dryas abrupt cooling event for example at which time the planet when from Holocene warm to 80% of the glacial cold with 80% of that change occurring in 15 years and 100% of the YD cooling occurring within 40 years.) As there are geomagnetic excursions at 6 of the Heinrich abrupt cooling events, it appears the super large very abrupt climate changes are caused by geomagnetic excursions. (The geomagnetic field intensity drops by a factor of around 5 during geomagnetic excursion. A weaker geomagnetic field allows more GCR to strike the planet which increases planetary cloud cover which cools the planet.)

The question then is what causes the cyclic geomagnetic excursions.

A secular geomagnetic change (called “archeomagnetic jerks”) is a smaller version of the mechanism that causes the cyclic geomagnetic excursions. Recently it has been discovered that in the last 5000 years there has been 10 archeomagnetic jerks and that cold periods correlate with the archeomagnetic jerks.

The word “secular” is used in this case as the geomagnetic field is changed in a region or regions on the planet which changes the tilt of the geomagnetic field. The polar regions of the geomagnetic field allow more GCR to strike the earth which increases planetary cloud cover which in turns cools the planet.

The archeomagnetic jerk moves the geomagnetic polar region closer to the equator so there is tropical cooling. As the geomagnetic pole no longer aligns with rotational axis of the planet there can also be some warming in specific higher latitude regions.

It appear the archeomagnetic jerks and the geomagnetic excursions are both caused by massive coronal mass ejections CME occur when an interrupted solar magnetic cycle restarts. The CME create a space charge differential in the ionosphere which creates a potential difference from ionosphere to planet’s surface. There are burn marks on the planet’s surface that correlate with the Younger Dryas cooling event and with a previous cooling event. (The 500,000 Carolina Bay burn marks which overlap showing evidence of restrike. The Carolina Bay burn marks all point in the North West direction as the electrical pulse follows the geomagnetic field lines and as the strike occurs over a period of time the earth rotation during the strike creates an elliptical burn mark.)

The planet’s liquid core integrates the massive external electromagnetic pulses to create a symmetrical magnetic dipole; however, that process takes around 1000 years which explains why the Younger Dryas cooling period was around 1000 years in duration.


Hi Kiwistonewall,
Clear and colourful. The colourful helps to keep the viewer engaged.

[william]

Are there connections between the Earth's magnetic field and climate?

sciences.blogs.liberation.fr/home/files/Courtillot07EPSL.pdf



geosci.uchicago.edu/~rtp1/BardPapers/responseCourtillotEPSL07.pdf

Also, we wish to recall that evidence of a correlation between archeomagnetic jerks and cooling events (in a region extending from the eastern North Atlantic to the Middle East) now covers a period of 5 millenia and involves 10 events (see f.i. Figure 1 of Gallet and Genevey, 2007). The climatic record uses a combination of results from Bond et al (2001), history of Swiss glaciers (Holzhauser et al, 2005) and historical accounts reviewed by Le Roy Ladurie (2004). Recent high-resolution paleomagnetic records (e.g. Snowball and Sandgren, 2004; St-Onge et al., 2003) and global geomagnetic field modeling (Korte and Constable, 2006) support the idea that part of the centennial-scale fluctuations in 14C production may have been influenced by previously unmodeled rapid dipole field variations. In any case, the relationship between climate, the Sun and the geomagnetic field could be more complex than previously imagined. And the previous points allow the possibility for some connection between the geomagnetic field and climate over these time scales.

Point 4: We first reiterate the fact that the “claims” made in our paper regarding correlations between cooling periods and archeomagnetic jerks were actually put forward by Gallet et al (2005, 2006). We do note that the causal relationship between cosmic ray flux and cloud cover suggested by Marsh and Svensmark (2000) would result in a correlation opposite to the one we find if the field geometry were axial and dipolar and this is precisely why we propose a mechanism of dipole tilt or non dipole geometry to interpret our observations. Gallet et al (2005) write: “ Another hypothesis is to assume that the incoming charged particles are deflected towards the poles, where the overall low humidity level due to cold temperatures limits cloud formation. If archeomagnetic jerks indeed correspond to periods of strongly inclined dipole, then the charged particles would interact with more humid air from lower latitude environments, leading to significantly larger cloud production and cooling.” And if this happens, there is no need to “overcome the more direct effect", as (mis)understood by BD07 (who seem to understand that a growing axial dipole is superimposed on a tilted dipole, which is not the case).

[william]

Paleomagnetic excursions

www.springerlink.com/content/k6x20160542j846q/

Paleomagnetic excursions recorded in the Yanchi Playa in middle hexi corridor, NW China since the last interglacial

Paleomagnetic determinations on lithological profiles of two paralleled long drilling cores covering the past 130 kyr B.P., GT40 and GT60, from the Yanchi Playa in the arid Northwestern China, indicate that a series of pronounced paleomagnetic excursions have been documented. By correlating our results with published regional and worldwide reports, 4 excursion events out of 10 apparent reversal signals (labeled from GT-1 to GT-10) were identified as excursion events coeval with the Mono Lake Event (28.4 kyr–25.8 kyr), Laschamp Event (43.3 kyr–40.5 kyr), Gaotai Event (82.8 kyr–72.4 kyr) and the Blake Event (127.4 kyr–113.3 kyr), respectively. GT-9 correlates with the above-mentioned Gaotai Event, GT-7 and GT-6 correspond to two stages of the Laschamp Event and GT-5 to the Mono Lake Event. It is noteworthy that the so-called Gaotai Event has not been reported as a pronounced paleomagnetic excursion in the Northwestern China.

Every magnetic excursion event corresponds to paleointensity minima, anteceding those established abrupt paleoclimatic change events, such as the Younger Drays and the Heinrich Events (H1–H6). Here, we tentatively propose that these geomagnetic excursions/reversals can be viewed as precursors to climate abruptness. During the transitional stages when the earth’s magnetic field shifted between a temporal normal and a negative period, the earth’s magnetic paleointensity fell correspondingly to a pair of minima. Although more precise chronology and more convincing rock magnetic parameter determinations are essentially required for further interpretation of their intricate coupling mechanism, these results may have revealed, to some extent, that the earth’s incessantly

changing magnetic field exerts an strong influence on the onset of saw-tooth shaped abrupt climate oscillations through certain feedback chains in arid Central Asia or even North Hemispheric high latitude regions

.

[poitsplace]

Apr 2, 2010 11:44:07 GMT william said:

Hi Poitsplace,
If planetary feedback is negative then the planet resists changes to planetary temperature by increasing or decreasing planetary clouds.

As Carter shows in his lecture the ice sheet analysis shows that there has been very large cyclic planetary temperature changes. (Glacial/interglacial cycle for example. Interglacial period starts abruptly, lasts around 10,000 years and ends abruptly. Why?)

A large powerful cyclic forcing mechanism is required to explain what is observed.

Planetary feedback is different for different things. For warming, albedo feedback is ever decreasing. Functional albedo feedback (those that are a part of temperatures that might be reached on warming) is even lower. Albedo feedback for cooling gets more and more powerful as it cools...until total glaciation...although differential deposition would cause surface rocks to be exposed eventually (a non-linear aspect)

Water vapor feedback for warming works to an extent...then latent heat and convection increases caused by water vapor become the chief energy carrier across the troposphere and it goes negative again. Latent heat and convection currently account for the bulk of surface cooling...and go up exponentially with temperature...a powerful negative feedback for warming. On the other hand if temperatures drop too low, it halts much of the energy transfer from the surface. As the ice cover at the poles increases it slams the breaks on the winds/ocean currents carrying energy to the poles and traps heat at the equator...preventing further glaciation (under most circumstances).

There are numerous other factors, many of which haven't even been found. It is very much a non-linear system. The most important aspect of the milankovitch cycles is that it changes the very nature of the feedbacks. During the phases of the milankovitch cycles that lead to glaciation, the interglacial temperature ranges are also unstable. Eventually the random walk of climate lands conditions squarely into those dominated by glacial feedbacks (albedo/desertification).

When the milankovitch cycles favor interglacial conditions, the interglacial conditions become stable again and eventually the random walk of the climate hits interglacial temperature ranges...and gets stuck there.

Oh, and I'm not saying the sun and earth's magnetic field don't have an impact...just that they are but two factors in the numerous subsystems that lead to the climate's fluctuations.

[william]

Milankovitch’s theory does not explain the glacial/interglacial cycle. There is currently no explanation as to what causes the glacial/interglacial cycle. For example tThere is no explain as to what caused the change from a 41 kyr to 100 kyr cycle. Based on Milankovitch's theory there should be 41 year cycle not a 100 kyr cycle. As noted below detailed paleo analysis does not support Milankovitch's theory.

What the evidence shows is the super massive Younger Dryas abrupt climate events triggers the change from glacial to interglacial and glacial to interglacial.

I agree with your comment and the data supports your comment, that during the glacial phase the lower latitude ice sheets amplify abrupt climate changes. The lower latitude ice sheets melt when the forcing warms the planet which amplifies the warming forcing the ice sheets also increase in area when the planet cools.

The albedo affect of an ice sheet is greater the lower its latitude there is more insolation at lower latitudes to reflect into space.

If there is not strong negative feedback (decreased planetary clouds) at the tropics I am not sure what would stop the ice sheets from advancing. The question water vapour is relative change in the greenhouse affect vs the relative change in cloud cover. Lindzen's data shows cloud feedback is negative which means the albedo change is greater than the greenhouse affect with works as a planetary temperature governor to stop the planet from getting too warm or too cold.


If you look at figure 1 in "The 41 kyr world: Milankovitch’s other unsolved mystery " by Maureen E. Raymo et al. it is clear when the planet was warmer there is there are no longer abrupt climate cycles which points towards negative feedback.



en.wikipedia.org/wiki/Milankovitch_cycles

100,000-year problem
The 100,000-year problem is that the eccentricity variations have a significantly smaller impact on solar forcing than precession or obliquity and hence might be expected to produce the weakest effects. However, observations show that during the last 1 million years, the strongest climate signal is the 100,000-year cycle. In addition, despite the relatively large 100,000-year cycle, some have argued that the length of the climate record is insufficient to establish a statistically significant relationship between climate and eccentricity variations.[4] Some models can however reproduce the 100,000 year cycles as a result of non-linear interactions between small changes in the Earth's orbit and internal oscillations of the climate system.[5][6]

400,000-year problem

The 400,000-year problem is that the eccentricity variations have a strong 400,000-year cycle. That cycle is only clearly present in climate records older than the last million years. If the 100 ka variations are having such a strong effect, the 400 ka variations might also be expected to be apparent. This is also known as the stage 11 problem, after the interglacial in marine isotopic stage 11 which would be unexpected if the 400,000-year cycle has an impact on climate. The relative absence of this periodicity in the marine isotopic record may be due, at least in part, to the response times of the climate system components involved — in particular, the carbon cycle.

Stage 5 problem
The stage 5 problem refers to the timing of the penultimate interglacial (in marine isotopic stage 5) which appears to have begun 10 thousand years in advance of the solar forcing hypothesized to have been causing it. This is also referred to as the causality problem.

Effect exceeds cause
420,000 years of ice core data from Vostok, Antarctica research station.

The effects of these variations are primarily believed to be due to variations in the intensity of solar radiation upon various parts of the globe. Observations show climate behaviour is much more intense than the calculated variations. Various internal characteristics of climate systems are believed to be sensitive to the insolation changes, causing amplification (positive feedback) and damping responses (negative feedback).

The unsplit peak problem

The unsplit peak problem refers to the fact that eccentricity has cleanly resolved variations at both the 95 and 125 ka periods. A sufficiently long, well-dated record of climate change should be able to resolve both frequencies [5], but some researchers interpret climate records of the last million years as showing only a single spectral peak at 100 ka periodicity. It is debatable whether the quality of existing data ought to be sufficient to resolve both frequencies over the last million years.

The transition problem Variations of Cyle Times, curves determined from ocean sediments

The transition problem refers to the change in the frequency of climate variations 1 million years ago. From 1-3 million years, climate had a dominant mode matching the 41 ka cycle in obliquity. After 1 million years ago, this changed to a 100 ka variation matching eccentricity. No reason for this change has been established.


Identifying dominant factor
Milankovic himself believed that reductions in summer insolation in northern high latitudes was the dominant factor leading to glaciation, which lead to him (incorrectly) deducing an approximately 41 kyr period for ice ages [7]. Subsequent research has shown that the 100 kyr eccentricity cycle is more important, resulting in 100,000-year ice age cycles of the Quaternary glaciation over the last few million years.



The 41 kyr world: Milankovitch’s other unsolved mystery by Maureen E. Raymo et al.

rsai.geography.ohio-state.edu/courses/G820.01/WI05%20climate%20history/2002PA000791.pdf


[1] For most of the Northern Hemisphere Ice Ages, from approx. 3.0 to 0.8 m.y., global ice volume varied predominantly at the 41,000 year period of Earth’s orbital obliquity. However, summer (or summer caloric half year) insolation at high latitudes, which is widely believed to be the major influence on high-latitude climate and ice volume, is dominated by the 23,000 year precessional period. Thus the geologic record poses a challenge to our understanding of climate dynamics.


Figure 1. Benthic d18O record from DSDP Site 607 in the North Atlantic (solid line) plotted to a paleomagnetic timescale. The magnetic field reversals are marked, as well as the transition from a
dominant 41 kyr to a 100 kyr world. B, Brunhes; M, Matuyama; J, Jaramillo; TOld, top of Olduvai; G, Gauss. Also shown is orbital obliquity (red dashed line).

[poitsplace]

Sadly, there may be no external reason discernible no matter how much we learn about the climate. The slow movement of the continents could simply cause a global energy flow change that interacts differently with the milankovitch cycles and other cycles.

The current configuration of continents is actually the most significant contributing factor in the ability of the earth to enter an ice age. I find the hubris of modern climate scientists just plain disturbing

Things like this just scream "I'm dying to blame CO2 at any cost" (from wikipedia so maybe they're not that into this belief)
"Seemingly, the long-lasting interglacial conditions that are documented during MIS 11 depend on the peculiar interplay between CO2 concentration and insolation. In fact, during periods of both eccentricity and precession minima, even small variations in total insolation might lead the control of climate to greenhouse gasses, in particular CO2."

It just never seems to occur to the deacons at the church of AGW that CO2 might be more of a proxy for the temperature of the oceans near one or both of the poles...or some other aspect of the climate cycles that would fit without bending over backward and placing effect before cause.