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[bluewave]

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[skierinvermont]

You can pretend you are deleting posts because they are off-topic, but since when has that rule ever been enforced in CC?

[FPizz]

Get over it. Nice post blue. Seems to be the case lately.

[blizzard1024]

A recent paper was just made available online showing the increase in Eurasian extreme winter cold

events and the strengthening of the Siberian High.

http://iopscience.io..._7_4_044044.pdf

Extreme cold winter weather events over Eurasia have occurred more frequently in recent years in spite of a warming global climate. To gain further insight into this regional mismatch with the global mean warming trend, we analyzed winter cyclone and anticyclone activities, and their interplay with the regional atmospheric circulation pattern characterized by the semi-permanent Siberian high. We found a persistent weakening of both cyclones and anticyclones between the 1990s and early 2000s, and a pronounced intensification of anticyclone activity afterwards. It is suggested that this intensified anticyclone activity drives the substantially strengthening and northwestward shifting/expanding Siberian high, and explains the decreased midlatitude Eurasian surface air temperature and the increased frequency of cold weather events. The weakened tropospheric midlatitude westerlies in the context of the intensified anticyclones would reduce the eastward propagation speed of Rossby waves, favoring persistence and further intensification of surface anticyclone systems.

Another new paper highlights changes in Siberian snow cover and declining Arctic sea ice.

http://www.agu.org/p...2JD018047.shtml

The loss of Arctic sea ice has wide-ranging impacts, some of which are readily apparent and some of which remain obscure. For example, recent observational studies suggest that terrestrial snow cover may be affected by decreasing sea ice. Here, we examine a possible causal link between Arctic sea ice and Siberian snow cover during the past 3 decades using a suite of experiments with the National Center for Atmospheric Research Community Atmospheric Model version 3. The experiments were designed to isolate the influence of surface conditions within the Arctic Ocean from other forcing agents such as low-latitude sea surface temperatures and direct radiative effects of increasing greenhouse gases. Only those experiments that include the observed evolution of Arctic sea ice and sea surface temperatures result in increased snow depth over Siberia, while those that maintain climatological values for Arctic Ocean conditions result in no snow signal over Siberia. In the former, Siberian precipitation and air temperature both increase, but because surface air temperatures remain below freezing during most months, the snowpack thickens over this region. These results suggest that Arctic Ocean surface forcing is necessary and sufficient to induce a Siberian snow signal, and that other forcings in combination can modulate the strength and geographic extent of the response.

These papers add to a 2010 study on reduced sea ice in the Kara and Barents regions

and extreme Eurasian winter cold.

http://oceanrep.geomar.de/8738/

The recent overall Northern Hemisphere warming was accompanied by several severe northern continental winters, as for example, extremely cold winter 2005/2006 in Europe

and northern Asia. Here we show that anomalous decrease of wintertime sea ice concentration in the Barents-Kara (B-K) Seas could bring about extreme cold events like winter 2005/2006. Our simulations with the ECHAM5 general circulation model demonstrate that lower-troposphere heating over the B-K Seas in the Eastern Arctic caused by the sea ice reduction may result in strong anti-cyclonic anomaly over the Polar Ocean and anomalous easterly advection over northern continents. This causes a

continental-scale winter cooling reaching -1.5°C, with more than three times increased probability of cold winter extremes over large areas including Europe. Our results imply that several recent severe winters do not conflict the global warming picture but rather supplement it, being in qualitative agreement with the simulated large-scale atmospheric circulation realignment. Furthermore, our results suggest that high-latitude atmospheric

circulation response to the B-K sea ice decrease is highly nonlinear and characterized by transition from anomalous cyclonic circulation to anticyclonic one and then again back to cyclonic type of circulation as the B-K sea ice concentration gradually reduces from 100% to ice free conditions. We present a conceptual model which may explain the nonlinear local atmospheric response in the B-K Seas region by counter play between convection over the surface heat source and baroclinic effect due to modified temperature gradients in the vicinity of the heating area.

Christopher Burt did an excellent job documenting the record Eurasian cold of early 2012.

http://www.wundergro...tml?entrynum=62

Although I am a winter lover and would love for this to be true...I am really skeptical that loss of sea ice and warming in the high arctic leads to colder than normal winters farther south.

IMO this is a knee-jerk "study" to scare people into thinking that global warming = global cooling so that more action can be taken. I believe what we are seeing is a more negative AO pattern which is cyclical. I remember in the 1990s after many years of highly positive AO/NAO winters, climate scientists were saying that global warming would lead to more positive AO/NAO patterns because the heights are expected to rise in the subtropics which increases the pressure gradient aloft and forces a stronger westerly jet. Now some have switched their studies to try to explain why it was so cold in Asia/Europe last year and now again this winter.

BUT...there could be some validity to this study as it could be mother nature's way of reducing the inflow of warmer atlantic waters into the arctic basin. If you continue to get negative AO patterns and more high pressure across Europe you eventually will slow down the warm atlantic current some to the Arctic basin. Plus if you cool the mid latitudes as this suggests, SSTs eventually will fall so eventually the Arctic ice recovers. This could be a breaking mechanism. But I remain skeptical....

[skierinvermont]

Although I am a winter lover and would love for this to be true...I am really skeptical that loss of sea ice and warming in the high arctic leads to colder than normal winters farther south.

IMO this is a knee-jerk "study" to scare people into thinking that global warming = global cooling so that more action can be taken. I believe what we are seeing is a more negative AO pattern which is cyclical. I remember in the 1990s after many years of highly positive AO/NAO winters, climate scientists were saying that global warming would lead to more positive AO/NAO patterns because the heights are expected to rise in the subtropics which increases the pressure gradient aloft and forces a stronger westerly jet. Now some have switched their studies to try to explain why it was so cold in Asia/Europe last year and now again this winter.

BUT...there could be some validity to this study as it could be mother nature's way of reducing the inflow of warmer atlantic waters into the arctic basin. If you continue to get negative AO patterns and more high pressure across Europe you eventually will slow down the warm atlantic current some to the Arctic basin. Plus if you cool the mid latitudes as this suggests, SSTs eventually will fall so eventually the Arctic ice recovers. This could be a breaking mechanism. But I remain skeptical....

1. Claiming something is "cyclical" is not an explanation for the observed behavior. People are so obsessed with "cycles" as if this is actually some sort of brilliant explanation. Plus we really don't have enough data to claim something is cyclical without knowing the physical cause.

2. People have been arguing about whether the AO/NAO will go more positive or negative for decades. Scientists and models were indicating both a more positive and negative trend before the recent negative trend. This is one more study added to the evidence. This is how science works.

3. You say the study could be valid because 'it is mother nature's way of reducing the inflow of warm atlantic waters into the arctic.' This is not a scientifically or logically valid argument. "Mother nature" doesn't WANT to do anything. She doesn't WANT to protect sea ice from melting. Maybe you do, but mother nature is governed by PHYSICS.

[nzucker]

1. Claiming something is "cyclical" is not an explanation for the observed behavior. People are so obsessed with "cycles" as if this is actually some sort of brilliant explanation. Plus we really don't have enough data to claim something is cyclical without knowing the physical cause.

2. People have been arguing about whether the AO/NAO will go more positive or negative for decades. Scientists and models were indicating both a more positive and negative trend before the recent negative trend. This is one more study added to the evidence. This is how science works.

3. You say the study could be valid because 'it is mother nature's way of reducing the inflow of warm atlantic waters into the arctic.' This is not a scientifically or logically valid argument. "Mother nature" doesn't WANT to do anything. She doesn't WANT to protect sea ice from melting. Maybe you do, but mother nature is governed by PHYSICS.

We do know the AO/NAO is cyclical, so that's nothing new here. It does seem as if we've shifted from saying global warming causes a more +AO/+NAO (remember the whole "modern winter" thing in Europe), to saying it causes a more -AO/-NAO after severe winters in the mid-latitudes like 09-10, 10-11, and February of 11-12 and the beginning of 12-13. The Siberian snow cover-->Rossby waves-->upper warming-->-AO is a well-studied and evidenced connection, but that doesn't mean the science hasn't been following the trend in winters rather than the trend in winters following the science.

[skierinvermont]

We do know the AO/NAO is cyclical, so that's nothing new here. It does seem as if we've shifted from saying global warming causes a more +AO/+NAO (remember the whole "modern winter" thing in Europe), to saying it causes a more -AO/-NAO after severe winters in the mid-latitudes like 09-10, 10-11, and February of 11-12 and the beginning of 12-13. The Siberian snow cover-->Rossby waves-->upper warming-->-AO is a well-studied and evidenced connection, but that doesn't mean the science hasn't been following the trend in winters rather than the trend in winters following the science.

Really you have data going back 500 years showing the AO/NAO/NAM to be cyclical? News to me. I'd love to see it! Even if 30-yr cycle existed over the last 90 years, that wouldn't mean that it is cyclical. All it might mean is that something caused the AO to be generally negative 1940-1970, giving the appearance of a cycle when no cycle actually exists. It could be generally negative for 10, positive for 50, negative for 30, random and chaotic for 50, positive for 20, negative for 20, random and chaotic for 70, etc. etc. etc. totally at random. You can't even show a 30-yr cycle without 300+ years of data.

Even the last 100 years of data I don't see anything that remotely resembles a "cycle." What's the cycle length? 30 years? 40 years? 60 years? I have no idea looking at this chart. Looks very chaotic to me. The most that could be said is that some periods have favored a -AO while others a +AO, but there definitely isn't even the beginning of a cycle (which would take 300+ years of data to demonstrate anyways).

[nzucker]

Really you have data going back 500 years showing the AO/NAO/NAM to be cyclical? News to me. I'd love to see it! Even if 30-yr cycle existed over the last 90 years, that wouldn't mean that it is cyclical. All it might mean is that something caused the AO to be generally negative 1940-1970, giving the appearance of a cycle when no cycle actually exists. It could be generally negative for 10, positive for 50, negative for 30, random and chaotic for 50, positive for 20, negative for 20, random and chaotic for 70, etc. etc. etc. totally at random. You can't even show a 30-yr cycle without 300+ years of data.

Even the last 100 years of data I don't see anything that remotely resembles a "cycle." What's the cycle length? 30 years? 40 years? 60 years? I have no idea looking at this chart. Looks very chaotic to me. The most that could be said is that some periods have favored a -AO while others a +AO, but there definitely isn't even the beginning of a cycle (which would take 300+ years of data to demonstrate anyways).

There is a lot of evidence about the NAO being cyclical going back hundreds of years. If you read Cullen and Mann's fascinating paper Mutliproxy Reconstructions of the North Atlantic Oscillations, the authors write, "The first, a reconstruction of the NAO SLP index based on tree ring records from Morocco and Finland as well as ice core data from Greenland, extends over 550 years. The authors found that periods of consistently high or low index values in their reconstruction were comparable in length to those of the instrumental period." We also know about the long mild period which allowed Norse settlers to colonize Greenland, followed by a much colder period in the North Atlantic. And it appears that the cycle has maintained its length since the 1500s according to these reconstructions; sure, there will always be variability surrounding a cyclical process (just like you'd argue that the overall global temperature trend is consistently up despite the plateau apparent in recent years), but that doesn't take away from the overall cyclical nature.

I don't think the term "cyclical" denies causation, either. There can be something causing the NAO to be negative for 30 years, and then positive for the next 40 years, but that doesn't mean it's not a cycle.

And again, the sarcastic tone you take in the argument is unnecessary. You don't need to make comments like "news to me" as it doesn't add anything to your argument and actually detracts in the eyes of people who don't like that sort of sarcasm.

http://www.meteo.psu.edu/holocene/public_html/shared/articles/cullenetal01.pdf

[skierinvermont]

There is a lot of evidence about the NAO being cyclical going back hundreds of years. If you read Cullen and Mann's fascinating paper Mutliproxy Reconstructions of the North Atlantic Oscillations, the authors write, "The first, a reconstruction of the NAO SLP index based on tree ring records from Morocco and Finland as well as ice core data from Greenland, extends over 550 years. The authors found that periods of consistently high or low index values in their reconstruction were comparable in length to those of the instrumental period." We also know about the long mild period which allowed Norse settlers to colonize Greenland, followed by a much colder period in the North Atlantic. And it appears that the cycle has maintained its length since the 1500s according to these reconstructions; sure, there will always be variability surrounding a cyclical process (just like you'd argue that the overall global temperature trend is consistently up despite the plateau apparent in recent years), but that doesn't take away from the overall cyclical nature.

I don't think the term "cyclical" denies causation, either. There can be something causing the NAO to be negative for 30 years, and then positive for the next 40 years, but that doesn't mean it's not a cycle.

And again, the sarcastic tone you take in the argument is unnecessary. You don't need to make comments like "news to me" as it doesn't add anything to your argument and actually detracts in the eyes of people who don't like that sort of sarcasm.

http://www.meteo.psu...ullenetal01.pdf

It's not sarcastic. It is news to me. You must have misinterpreted the tone. It was not sarcastic or condescending.

You have misrepresented the Cullen and Mann study. They actually find the opposite of what you suggest. Did you really read it? I find it hard to believe you would still have so much confidence in a long-term cycle of consistent length if you had read the study.

1. The quote you provide is them referencing another previous paper. 2. You have misunderstood the quoted section. 3. They specifically conclude the opposite of your mis-interpretation of the quoted section.

Points 2 and 3 are explained further below.

2. The quote doesn't say there is a consistent cycle. It simply says that periods of persistently +NAO or -NAO conditions of "comparable lengths to those of the instrumental record" have occurred previously and that the persistence of a -NAO such as occurred from 1950-1970 or the persistence of a +NAO (such as occurred from 1970 until the early 2000s) have occurred previously. In other words, + or - conditions have persisted for as long as 20-40 years historically, but that does not imply that there is a consistent 20, or 30, or 40 year half-cycle. It just means there are persistent low and high periods sometimes. You claim that the "cycle has maintained its length since the 1500s." But that is not what the quote says at all. It is saying that there have been persistent + or - periods in the past (of varying lengths, but some of "comparable length to the instrumental period"). And Cullen and Mann specifically find no long-term cycle.

3. Cullen and Mann actually conclude the following when performing a statistical analysis looking for cycles:

"The 2.3 and 7-8 year peaks are also present and significant at the 99% level in the R4 series over the full 1750-1979 interval. Also exceeding the 99% significance level is a peak centered on 12.5 years... The low frequency (70 year) mode is not present in R4 from 1750 to 1979 or in the instrumental record from 1874 to 1995."

They suggest the 2.3 year cycle is related to the QBO, the 7-8 year peak related to "a Pacific Atlantic connection" and the 12.5 year cycle related to "coupled tropical ocean-atmosphere dynamics." But there is no low frequency (long-term) cycle.

I guess it depends on your use of the term "cycle." If all you are trying to say is that sometimes the NAO/AO/NAM can be persistently positive or negative for long periods of 10, 20, 30 even 40+ years, then yeah the NAO/AO/NAM is "cyclical." But if you mean to say that there is a consistent cycle of 50, 60 80+ years (half cycles 25, 30, 40+ respectively) then no I do not believe that there is evidence of that. The "consensus reconstruction" by Cullen and Mann finds no such cycle. Some other reconstruction do find some long-term modes of variability but they don't appear to be very robust.

Most people tend to use the term "cycle" in the latter sense (which is how you used it by incorrectly saying the cycles maintain a consistent length), and have often used the concept of cycle to suggest there will be a long-persistent period of -NAO forthcoming for essentially no other reason than the NAO is quote "cyclical." In reality, there is no consistent cycle. There are just sometimes persistent negative or positive periods which no doubt have physical explanations. Without knowing which physical explanations will be at play the next 20, 30, 40+ years it is not possible to predict what the NAO will be the next 20, 30, 40+ years, nor is it possible to suggest that the recent -NAO is part of a long-term "cycle."

[WeatherRusty]

A wheel cycles, a pendulum cycles, the seasons cycle. A pattern which repeats itself about a central mean cycles.

Variability about a central mean is not necessarilly a cycle. An occillation is not necessarilly cyclical. Lacking defined repeatability, variability and occillations do not imply cyclical behaviour.

[blizzard1024]

1. Claiming something is "cyclical" is not an explanation for the observed behavior. People are so obsessed with "cycles" as if this is actually some sort of brilliant explanation. Plus we really don't have enough data to claim something is cyclical without knowing the physical cause.

2. People have been arguing about whether the AO/NAO will go more positive or negative for decades. Scientists and models were indicating both a more positive and negative trend before the recent negative trend. This is one more study added to the evidence. This is how science works.

3. You say the study could be valid because 'it is mother nature's way of reducing the inflow of warm atlantic waters into the arctic.' This is not a scientifically or logically valid argument. "Mother nature" doesn't WANT to do anything. She doesn't WANT to protect sea ice from melting. Maybe you do, but mother nature is governed by PHYSICS.

I agree with Nzucker. Your tone is sarcastic. But in any event, from everything I have learned in atmospheric science. there are a lot of cycles, waves, oscillations and feedbacks which govern how the atmosphere works. This is very very basic atmospheric science. There are also breaking mechanisms that make our climate pretty stable. There is a lot of evidence from the paleoclimate records that since the ice sheets vanished around 8-10 K years before present our climate has been essentially fairly stable. The holocene has averaged plus or minus 2.5C per century which is less than the variability than when there were huge ice sheets. This was postulated to be plus or minus 5C/century or so from the GISP ice core. This graph is from GISP ice accumulation rates from Alley, R.B.. 2004. GISP2 Ice Core Temperature and Accumulation Data.

IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series #2004-013. NOAA/NGDC Paleoclimatology Program, Boulder CO, USA. .

Today's climate change is well within the range of past climate changes. Nothing unusual. It would not surprise me at all to see an Arctic sea ice recovery in the next 10-20 years too.

[blizzard1024]

It's not sarcastic. It is news to me. You must have misinterpreted the tone. It was not sarcastic or condescending.

You have misrepresented the Cullen and Mann study. They actually find the opposite of what you suggest. Did you really read it? I find it hard to believe you would still have so much confidence in a long-term cycle of consistent length if you had read the study.

1. The quote you provide is them referencing another previous paper. 2. You have misunderstood the quoted section. 3. They specifically conclude the opposite of your mis-interpretation of the quoted section.

Points 2 and 3 are explained further below.

2. The quote doesn't say there is a consistent cycle. It simply says that periods of persistently +NAO or -NAO conditions of "comparable lengths to those of the instrumental record" have occurred previously and that the persistence of a -NAO such as occurred from 1950-1970 or the persistence of a +NAO (such as occurred from 1970 until the early 2000s) have occurred previously. In other words, + or - conditions have persisted for as long as 20-40 years historically, but that does not imply that there is a consistent 20, or 30, or 40 year half-cycle. It just means there are persistent low and high periods sometimes. You claim that the "cycle has maintained its length since the 1500s." But that is not what the quote says at all. It is saying that there have been persistent + or - periods in the past (of varying lengths, but some of "comparable length to the instrumental period"). And Cullen and Mann specifically find no long-term cycle.

3. Cullen and Mann actually conclude the following when performing a statistical analysis looking for cycles:

"The 2.3 and 7-8 year peaks are also present and significant at the 99% level in the R4 series over the full 1750-1979 interval. Also exceeding the 99% significance level is a peak centered on 12.5 years... The low frequency (70 year) mode is not present in R4 from 1750 to 1979 or in the instrumental record from 1874 to 1995."

They suggest the 2.3 year cycle is related to the QBO, the 7-8 year peak related to "a Pacific Atlantic connection" and the 12.5 year cycle related to "coupled tropical ocean-atmosphere dynamics." But there is no low frequency (long-term) cycle.

I guess it depends on your use of the term "cycle." If all you are trying to say is that sometimes the NAO/AO/NAM can be persistently positive or negative for long periods of 10, 20, 30 even 40+ years, then yeah the NAO/AO/NAM is "cyclical." But if you mean to say that there is a consistent cycle of 50, 60 80+ years (half cycles 25, 30, 40+ respectively) then no I do not believe that there is evidence of that. The "consensus reconstruction" by Cullen and Mann finds no such cycle. Some other reconstruction do find some long-term modes of variability but they don't appear to be very robust.

Most people tend to use the term "cycle" in the latter sense (which is how you used it by incorrectly saying the cycles maintain a consistent length), and have often used the concept of cycle to suggest there will be a long-persistent period of -NAO forthcoming for essentially no other reason than the NAO is quote "cyclical." In reality, there is no consistent cycle. There are just sometimes persistent negative or positive periods which no doubt have physical explanations. Without knowing which physical explanations will be at play the next 20, 30, 40+ years it is not possible to predict what the NAO will be the next 20, 30, 40+ years, nor is it possible to suggest that the recent -NAO is part of a long-term "cycle."

This looks pretty cyclical to me just eyeballing it. It depends on how it is defined.

[WeatherRusty]

blizzard,

When was the last time GLOBAL temperature was >1 or 2C warmer than today? I think that you will find at least 15,000,000 ybp. There was no permanent Greenland ice sheet nor a permanent northern polar cap either, although the Antarctic ice sheet was well established going back to about 33,000,000 ybp.

The Earth's climate has no preferred state. It becomes what it is forced to become, and it does not "try" to remain in any given state. The Holocene has been relatively stable because the forcing has been quite consistant. Warmer periods tend to display less climatic variability, however a changing climate displays greater variability do to the maximizing of entropy production.

[skierinvermont]

This looks pretty cyclical to me just eyeballing it. It depends on how it is defined.

I see no clearly defined cycle. It looks like there have been low periods and high periods but not clear repeating cycle.

[blizzard1024]

blizzard,

When was the last time GLOBAL temperature was >1 or 2C warmer than today? I think that you will find at least 15,000,000 ybp. There was no permanent Greenland ice sheet nor a permanent northern polar cap either, although the Antarctic ice sheet was well established going back to about 33,000,000 ybp.

The Earth's climate has no preferred state. It becomes what it is forced to become, and it does not "try" to remain in any given state. The Holocene has been relatively stable because the forcing has been quite consistant. Warmer periods tend to display less climatic variability, however a changing climate displays greater variability do to the maximizing of entropy production.

I agree. The Earth has no preferred climate state. Wasn't it warmer 6-8 thousand years ago by 2-4C from orbital parameters??? But overall the Holocene has been a fairly stable climate and it would take a lot of forcing to change this. When there were large ice NH sheets, small changes in albedo, changes in elevation of the ice sheet, melting ice sheets and freshening of the ocean shutting down the Atlantic MOC led to a much more variable erratic climate system when compared to today. 1.7 watts/m2 from a 40% increase in CO2 is small and even if we see a doubling, 3.7 watts/m2 won't do much IMO. Cloud cover changes could easily negate this and there is satellite and radiation evidence i.e. Spencer and Braswell (2008) that suggests a negative cloud feedback to warming. Also Lindzen's IRIS effect was not effectively disproven in my opinion.

[nzucker]

I see no clearly defined cycle. It looks like there have been low periods and high periods but not clear repeating cycle.

It just depends on how strict of criteria you apply.

[skierinvermont]

I agree with Nzucker. Your tone is sarcastic. But in any event, from everything I have learned in atmospheric science. there are a lot of cycles, waves, oscillations and feedbacks which govern how the atmosphere works. This is very very basic atmospheric science. There are also breaking mechanisms that make our climate pretty stable. There is a lot of evidence from the paleoclimate records that since the ice sheets vanished around 8-10 K years before present our climate has been essentially fairly stable. The holocene has averaged plus or minus 2.5C per century which is less than the variability than when there were huge ice sheets. This was postulated to be plus or minus 5C/century or so from the GISP ice core. This graph is from GISP ice accumulation rates from Alley, R.B.. 2004. GISP2 Ice Core Temperature and Accumulation Data.

IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series #2004-013. NOAA/NGDC Paleoclimatology Program, Boulder CO, USA. .

Today's climate change is well within the range of past climate changes. Nothing unusual. It would not surprise me at all to see an Arctic sea ice recovery in the next 10-20 years too.

There are two very serious issues with your conclusion that temperature changes over the last 10,000 years have had rates of up to 2.5C per century.

First, as I have reminded you several times already, GISP is not global. It is one single location on earth. Obviously single locations have far more temperature variability than the globe does.

Second of all, it does appear there are a couple very spiky peaks to around 2.5C/century which would match the rate of warming the last 40 years if it were global (which GISP2 is not), but the majority appears to be within 1C/century.

So since GISP2 is not global, it is difficult to say much about anything prior to 1000-2000 years ago. For the period where we have decent global data over the last 1000-2000 years, there is high confidence that the rate of temperature change recently is unprecedented. The warmth is also unprecedented. We are likely warmer than any time in the last 2000 years and the rate of warming is faster than any in the last 2000 years.

Finally, as I am sure you are aware AGW theory is not remotely dependent upon the idea that modern temperature change is unprecedented. Large temperature variations in the past only prove that climate sensitivity and positive feedbacks are large. They do nothing to disprove the basic physics that CO2 causes warming.

[skierinvermont]

It just depends on how strict of criteria you apply.

No not really. I couldn't even venture a guess as to what the cycle length might be. There are low periods of 10, 20, 30 and 40 years, and high periods of 10, 20, 30, and 40 years.

So is the cycle 20, 40, 60, or 80 years long?

120 years is no where near long enough to establish the existence of a repeating long-term cycle. You'd need at least 300 years of data.

As I said above, Mann and Cullen also find no such long term cycle in the instrumental or the 300+ year record.

[skierinvermont]

I agree. The Earth has no preferred climate state. Wasn't it warmer 6-8 thousand years ago by 2-4C from orbital parameters??? But overall the Holocene has been a fairly stable climate and it would take a lot of forcing to change this. When there were large ice NH sheets, small changes in albedo, changes in elevation of the ice sheet, melting ice sheets and freshening of the ocean shutting down the Atlantic MOC led to a much more variable erratic climate system when compared to today. 1.7 watts/m2 from a 40% increase in CO2 is small and even if we see a doubling, 3.7 watts/m2 won't do much IMO. Cloud cover changes could easily negate this and there is satellite and radiation evidence i.e. Spencer and Braswell (2008) that suggests a negative cloud feedback to warming. Also Lindzen's IRIS effect was not effectively disproven in my opinion.

The peer-reviewed literature (and basic logic) provides very high confidence that net feedbacks are positive. Probably between 1.5 to 3X.

[blizzard1024]

There are two very serious issues with your conclusion that temperature changes over the last 10,000 years have had rates of up to 2.5C per century.

First, as I have reminded you several times already, GISP is not global. It is one single location on earth. Obviously single locations have far more temperature variability than the globe does.

Second of all, it does appear there are a couple very spiky peaks to around 2.5C/century which would match the rate of warming the last 40 years if it were global (which GISP2 is not), but the majority appears to be within 1C/century.

So since GISP2 is not global, it is difficult to say much about anything prior to 1000-2000 years ago. For the period where we have decent global data over the last 1000-2000 years, there is high confidence that the rate of temperature change recently is unprecedented. The warmth is also unprecedented. We are likely warmer than any time in the last 2000 years and the rate of warming is faster than any in the last 2000 years.

Finally, as I am sure you are aware AGW theory is not remotely dependent upon the idea that modern temperature change is unprecedented. Large temperature variations in the past only prove that climate sensitivity and positive feedbacks are large. They do nothing to disprove the basic physics that CO2 causes warming.

Well if we look at Greenland's temperature records you can see that the changes in the last 100-150 years are well within the bounds of the Holocene climate change in Greenland. Plus, how can you say that there was no medieval warm period? How can you be sure that it is warmer now than it was 1000-2000 years ago? Tree ring proxy records are very unreliable and the statistics that were used were very suspect. We all know the Yamal tree dataset looked cherry picked...remember that one tree... YAD061!!!! Are we are to believe that our climate was rock steady for centuries until 1900 and then mankind has turned on the heat in the 20th century?? This is very suspect to me. Always has been. Plus the rate of climate change late 20th century is not different than between 1900 and 1940...plus there has been no statistically significant warming since the mid 1990s. Of course, climate scientists continue to lower temperatures earlier in the instrument record and warm them late in the period. You can believe this if you want. But it seems fishy to me. Why are all the adjustments that are made lead to more recent warming? You would think there would be some times when records are wrong and indicate cooler recent conditions and warmer earlier conditions. I have not seen this. Just because something is peer-reviewed in the current "political climate" means little. I actually have peer reviewed some papers in Meteorology and the garbage that makes it through now-a-days amazes me compared to 20 years ago. Peer reviewed literature is not proof of anything. I have read many of these peer reviewed papers and they are unconvincing...many use models to "validate" or prove something about climate. Come on... man! These are just models. Models don't prove anything.

Climate sensitivity is higher during glaciations and lower during interglacials suggesting ice sheets, albedo effects and ocean currents have more of an effect on the variations in climate than CO2. Like I have said before, the absorption bands for CO2 are most effective at -50C...this is the 15 micron band. The main effect being at high altitudes in the troposphere in the tropics. Greenhouse effect enhancement suggests there should be a "hot spot" in the upper tropical troposphere. The lower troposphere and surface has warmed more than the higher altitudes in the troposphere. This is inconsistent with greenhouse amplification. This is a well known problem with this theory that has not been reconciled except for that thermal wind paper which is tenuous at best IMO. Plus, clouds and therefore albedo variations are also very uncertain and there are studies that show they lead to negative feedbacks. How can you assume large positive feedbacks in our climate system under the current climate boundary conditions which are vastly different from when ice sheets dominated the NH land masses? Anyway, appreciate the dialogue and debate...have a happy new year and we will continue. This has forced me to dig deeper and learn more. Thanks.

[skierinvermont]

More denier lies than I have the time or energy to explain at the moment.,

[nzucker]

No not really. I couldn't even venture a guess as to what the cycle length might be. There are low periods of 10, 20, 30 and 40 years, and high periods of 10, 20, 30, and 40 years.

So is the cycle 20, 40, 60, or 80 years long?

120 years is no where near long enough to establish the existence of a repeating long-term cycle. You'd need at least 300 years of data.

As I said above, Mann and Cullen also find no such long term cycle in the instrumental or the 300+ year record.

30-40 years seems to cover it decently for this century, and some form of oscillation dates back 550 years so we're not just talking about the 1900s here. There could be cycles within cycles for the NAO as we see within the sun, so the periodicity doesn't have to be one set number.

[skierinvermont]

30-40 years seems to cover it decently for this century, and some form of oscillation dates back 550 years so we're not just talking about the 1900s here. There could be cycles within cycles for the NAO as we see within the sun, so the periodicity doesn't have to be one set number.

I already agreed that it is oscillatory (IE there are persistent low and high periods of various lengths). The question is whether there are cycles of 'consistent length' as you claimed. The 300+ year record doesn't show that and the instrumental record doesn't either (as the paper you posted says quite clearly).

When you claim the cycle length is 30-40 years I honestly don't even know whether you are talking about the length of the full cycle or the half-cycle.

There's a negative period of 19 years from '53-'72. There's a 35 year positive period from '72-07.

There's a 23 year period from '30-53 where I'm not sure if it's neutralish, but it tends to lean positive. Then a 28 year period of positive conditions from '02-30. Or you could argue that '02-53 is one big long 51 year positive period.

Then there's a 42 year period from 1860 to 1902 of chaotic random conditions.

So we've got half cycles of 19, 35, 51, and then a 42 year period of chaotic random.

Or we've got half cycles of 19, 35, 28 and two mixed periods of 23 and 42 years.

I don't see anything remotely resembling a cycle. More likely there are 3rd variables that cause persistent low and high periods of varying lengths, as well as periods that show very little tendency at all (more chaotic). In addition physically that is FAR FAR more likely.

[blizzard1024]

More denier lies than I have the time or energy to explain at the moment.,

Your arrogant. I am not a DENIER. The atmosphere is way more complex that the simplistic view that a

trace gas with weak IR absorbing qualities is dominate. That is why METs question such incredible

claims by climate scientists. If you really understood atmospheric science you would not be calling me a "denier".

Extraordinary claims need extraordinary proof which is lacking. The earth warms and cools. It's been happening

for millions and millions and millions of years. CO2 dominates the climate system...this seems to be an assumption

and all studies are therefore invalid if they don't somehow "prove" that recent climate change and increasing CO2 are

to blame. I feel sorry for anyone going into climate science. If you question anything, your career is over.

You get labeled and probably banished. The scientific method is being abandoned here. Science is supposed to

question everything until there is indisputable proof. With climate science you have to believe. Its like a religion for

many.

Great way to advance the "science".

[The_Global_Warmer]

Your arrogant. I am not a DENIER. The atmosphere is way more complex that the simplistic view that a

trace gas with weak IR absorbing qualities is dominate. That is why METs question such incredible

claims by climate scientists. If you really understood atmospheric science you would not be calling me a "denier".

Extraordinary claims need extraordinary proof which is lacking. The earth warms and cools. It's been happening

for millions and millions and millions of years. CO2 dominates the climate system...this seems to be an assumption

and all studies are therefore invalid if they don't somehow "prove" that recent climate change and increasing CO2 are

to blame. I feel sorry for anyone going into climate science. If you question anything, your career is over.

You get labeled and probably banished. The scientific method is being abandoned here. Science is supposed to

question everything until there is indisputable proof. With climate science you have to believe. Its like a religion for

many.

Great way to advance the "science".

This is not even close to reality. I am sorry that the Science as of now show's us a reality that does not fit your approval. But there is a couple thing's that your trying to portray that are now where close to reality.

1. This Galileo Galilee argument highlighted in the red. Is a bold face lie. You come and go on and on but never post anything of substance contrary to GHG warming. You think if you had evidence of a substantial nature that stands next to GHG's as an explanation of the Earth's warming or evidence that GHG's do not cause any warming that it would be thrown out and you would be labeled and banished as a heretic. That is funny Man. That is insanely absurd.

2. It's not 1617. Our Tool's are a bit better than Galileo's telescope. We do not get our understanding of our reality or in this case climate system from a book called The Holy Bible. Galileo is actually on our team. Or he was when he was alive.

Why not list 10 Scientists who have shown us evidence that deserves to be on equal or near equal footing and their work the last couple decades, let's see their data that got then banished and thrown out of Science for good. I am sure you can show us 10 scientists who have been labeled for bringing forth evidence to denounce GHG warming, you can do a where are they now thing. Since they have been labeled and banned from climate science, but mostly their career is over.

You can't use Roy Spencer and John Christy their career's are thriving more than most could dream of in climate science.

[blizzard1024]

This is not even close to reality. I am sorry that the Science as of now show's us a reality that does not fit your approval. But there is a couple thing's that your trying to portray that are now where close to reality.

1. This Galileo Galilee argument highlighted in the red. Is a bold face lie. You come and go on and on but never post anything of substance contrary to GHG warming. You think if you had evidence of a substantial nature that stands next to GHG's as an explanation of the Earth's warming or evidence that GHG's do not cause any warming that it would be thrown out and you would be labeled and banished as a heretic. That is funny Man. That is insanely absurd.

2. It's not 1617. Our Tool's are a bit better than Galileo's telescope. We do not get our understanding of our reality or in this case climate system from a book called The Holy Bible. Galileo is actually on our team. Or he was when he was alive.

Why not list 10 Scientists who have shown us evidence that deserves to be on equal or near equal footing and their work the last couple decades, let's see their data that got then banished and thrown out of Science for good. I am sure you can show us 10 scientists who have been labeled for bringing forth evidence to denounce GHG warming, you can do a where are they now thing. Since they have been labeled and banned from climate science, but mostly their career is over.

You can't use Roy Spencer and John Christy their career's are thriving more than most could dream of in climate science.

The science is not even close to reality. To think we have the climate system all figured out and that is on rock solid ground as planetary motion, a round earth or even gravity is ridiculous. Again, meteorologists understand the atmosphere and its complexities and to me it is quite arrogant people think these catastrophic scenarios are science.

I know quite a few students that chose to not pursue academics beyond M.S. because they had to tie everything into global warming in their studies to get funding. And if they didn't believe or had legitimate questions they were blasted even worse than one gets on this forum. Basically there were done. So, it is all figured out. Done. Galileo used real physics and mathematics to proof planetary motion. Newton proved gravity and forces of motion etc using physics/math. This is real science. Roy Spencer, John Christy, Richard Lindzen, Bill Gray, Bob Carter to name a few are really good scientists. I know that their reputations are in ruins (not careers) for asking and investigating real questions on this whole theory. They established their careers long before CAGW became en vogue. There work is largely discounted now and that is wrong. And the Svenmark cosmic ray stuff really has some merit and is worth looking further into. It can't be just a coincidence that we went through a period of low sunspot activity and we had a little ice age. Beryllium studies show that the medieval warm period and modern warm period came at an active time for the sun...solar grand maxima. It is warmer now. There has to be something here. Or it is just a coincidence? I doubt it.

But it would derail the whole CAGW train. So, it is considered rubbish. Its called group think and I believe most climatologists today are stuck. These are just my personal opinions. I am entitled to that. If you believe all this stuff and have a career in it great. Good for you. I remain skeptical of CAGW and even skeptical that CO2 will be able to influence the climate out of its natural bounds. There is no proof. Fortunately, I just forecast the weather for a living out to 7 days...beyond that I leave for everyone else and I wish everyone good luck.

[WeatherRusty]

Your arrogant. I am not a DENIER. The atmosphere is way more complex that the simplistic view that a

trace gas with weak IR absorbing qualities is dominate. That is why METs question such incredible

claims by climate scientists. If you really understood atmospheric science you would not be calling me a "denier".

Extraordinary claims need extraordinary proof which is lacking. The earth warms and cools. It's been happening

for millions and millions and millions of years. CO2 dominates the climate system...this seems to be an assumption

and all studies are therefore invalid if they don't somehow "prove" that recent climate change and increasing CO2 are

to blame. I feel sorry for anyone going into climate science. If you question anything, your career is over.

You get labeled and probably banished. The scientific method is being abandoned here. Science is supposed to

question everything until there is indisputable proof. With climate science you have to believe. Its like a religion for

many.

Great way to advance the "science".

Yes you are a denier. The science which you denounse and marginalize is accepted by the vast majority of climate scientists, universities and scientific bodies world wide. Now you will deny that also, or come up with excuses for why there is no true scientific consensus.

Skier is not arrogant simply because he stands behind the science...which he has learned quite well by the way...in no way is he blindly accepting the preachings of some religion. And neither am I.

Listen to yourself..."CO2 dominates the climate system".....NO IT DOES NOT....and no one claims as much...that's a strawman argument. The Sun and the cosmic background microwave radiation account for 255K of Earth 288K temperature. The greenhouse effect the other 33K. CO2 only 6K of that 33K. A doubling of CO2 will increase that 33K by (1.2K + X) where X is dependent on climate sensitivity.

Increasing greenhouse gases beyond the natural background level produces a marginal difference in the total temperature of the Earth. Simple. 2,3 or 4K is a minor contribution, not dominant, yet those 2,3 or 4K will make a huge difference to the living conditions on the planet. Simple.

[WeatherRusty]

The science is not even close to reality. To think we have the climate system all figured out and that is on rock solid ground as planetary motion, a round earth or even gravity is ridiculous. Again, meteorologists understand the atmosphere and its complexities and to me it is quite arrogant people think these catastrophic scenarios are science.

I know quite a few students that chose to not pursue academics beyond M.S. because they had to tie everything into global warming in their studies to get funding. And if they didn't believe or had legitimate questions they were blasted even worse than one gets on this forum. Basically there were done. So, it is all figured out. Done. Galileo used real physics and mathematics to proof planetary motion. Newton proved gravity and forces of motion etc using physics/math. This is real science. Roy Spencer, John Christy, Richard Lindzen, Bill Gray, Bob Carter to name a few are really good scientists. I know that their reputations are in ruins (not careers) for asking and investigating real questions on this whole theory. They established their careers long before CAGW became en vogue. There work is largely discounted now and that is wrong. And the Svenmark cosmic ray stuff really has some merit and is worth looking further into. It can't be just a coincidence that we went through a period of low sunspot activity and we had a little ice age. Beryllium studies show that the medieval warm period and modern warm period came at an active time for the sun...solar grand maxima. It is warmer now. There has to be something here. Or it is just a coincidence? I doubt it.

But it would derail the whole CAGW train. So, it is considered rubbish. Its called group think and I believe most climatologists today are stuck. These are just my personal opinions. I am entitled to that. If you believe all this stuff and have a career in it great. Good for you. I remain skeptical of CAGW and even skeptical that CO2 will be able to influence the climate out of its natural bounds. There is no proof. Fortunately, I just forecast the weather for a living out to 7 days...beyond that I leave for everyone else and I wish everyone good luck.

No, it's real physics which you fail to understand. That was Copernicus and Kepler, not Galileo. Ever heard of Max Planck, Einstein, Stefan and Boltzmann and the like? Their science provides the foundation for radiative physics which you fail to understand.

[FloridaJohn]

Plus, how can you say that there was no medieval warm period? How can you be sure that it is warmer now than it was 1000-2000 years ago?

Let me ask a couple questions about your line of reasoning here. Regardless of the magnitude of the warming period,

What was the mechanism for the warming during the Medivial Warming Period?

What is the mechanism for the current warming period?

How are they the same, and how are they different?

[blizzard1024]

No, it's real physics which you fail to understand. That was Copernicus and Kepler, not Galileo. Ever heard of Max Planck, Einstein, Stefan and Boltzmann and the like? Their science provides the foundation for radiative physics which you fail to understand.

 

Its because I understand radiative transfer and physics is why I am skeptical.  You guys are clueless and brainwashed. You can't refute that clouds are a big unknown and could cancel a small radiative effect of CO2. 1C for a doubling is known...duh...yes I took undergrad and graduate level radiative transfer. My professor, Dr Craig Bohren from PSU, who is now retired was a nuclear physicist and an expert in radiative transfer and thermo. He was an awesome professor and a GREAT teacher.  He is skeptical of all this horse**** and after retiring has stated that basically you can't get any funding if you don't "believe" in the CAGW scenario. Other more senior professors that have tenure locked up or are retired have stated the same thing. You guys can live in your fantasy world all you want.  The earth's climate will always be changing...always. Even an increase in 1-2C over 100 years won't be that big of a deal. Sea levels will rise and fall...people will have to adapt. In fact, a human species that can adapt to any climate change is good because when the next ice age comes...it is going to be real bad. Happy New Year and good luck.