Issues the Climate Change Contrarians Need to Address

[donsutherland1]

With the NOAA reporting that July 2012 eclipsed July 1936 to become the warmest month ever recorded in the contiguous U.S., those taking the minority contrarian position on climate change launched a full-scale attack in the blogosphere. Anthony Watts dismissed the record, writing that the U.S. temperature record results from "a mishmash of urban, semi-urban, rural, airport and non-airport stations, some of which are sited precariously in observers backyards, parking lots, near air conditioner vents, airport tarmac, and in urban heat islands." The Goddard blog charged that "NCDC Tampers With July Data For Global Warming Propaganda Purposes" and that "July 1936 was much hotter." Going even farther, Weatherbell meteorologist Joe Bastardi retweeted a message alleging that a new experiment demonstrated that CO2 has no radiative forcing properties.

In general, if one seeks to prove or disprove a hypothesis, one undertakes an objective examination of the data. Based on that data, one reaches one's conclusions. Whether one uses the GISS, NCDC, or HadCRUT datasets, the message is clear that the world is warming. In the warming global climate, the U.S. is also warming. Since 2000, July has had a temperature departure of +1σ or more above the NCDC's 20th century mean temperature in 61.5% of the years or about once every 1.6 years. The 1895-1999 period saw such readings in just 12.4% of the years or about once every 8.1 years. Put another way, the statistical frequency of such warmth in July is almost 5 times what it was in the earlier 1895-1999 timeframe. When it comes to extreme warmth (2σ or more above the 20th century mean), the 2000-2012 period has had 4 such cases (30.8% of years). The entire 1895-1999 period had 3 such cases (2.9% of years). In other words, one in every 3.3 years has seen July record a +2σ anomaly during the 2000-2012 period vs. one in 35.0 years during the 1895-1999 timeframe. Readings of at least 2σ above the 20th century mean have been more than 10 times as frequent as they were during the earlier period.

The January-July 2012 period has been particularly extreme, with a mean temperature of 56.41°F (4.003σ above the 20th century mean). That mark decimated the earlier record set just last year by 1.08°F. It was 1.001σ above that record. The three warmest January-July periods have occurred in 2000, 2011, and 2012. Since 2000, the mean January-July anomaly has been 1.433σ above the 20th century baseline.

The annual U.S. data reveals a similar pattern. Since 2000, the annual mean temperature has been +1σ or more above the NCDC's 20th century mean temperature in 83.3% of the years or about once every 1.2 years. The 1895-1999 period saw such anomalies in just 16.2% of the years or about once every 6.2 years. Put another way, the statistical frequency of such warmth is now a little more than 5 times what it was in the earlier 1895-1999 timeframe. When it comes to extreme warmth (2σ or more above the 20th century mean), the 2000-2011 period has had such anomalies in 8.3% of years (given the January-July anomaly of just over 4σ, that figure will very likely rise to 15.4% of years at the end of 2012). The 1895-1999 period saw such warmth in 3.8% of years. In other words, one in every 12.0 years has seen the annual U.S. mean temperature reach or exceed +2σ above the 20th century baseline during the 2000-2011 period vs. one in 26.3 years during the 1895-1999 timeframe. Readings of at least 2σ above the 20th century mean have been more than twice as frequent as they were during the earlier period (and that frequency will double shoudl 2012 have a 2σ departure). Since 2000, the annual anomaly has been an average of 1.437σ above the 20th century baseline. The last year with a negative annual anomaly was 1996, with a -0.206σ departure. The last year with an annual mean temperature of 1σ or more below normal was 1979 (-1.363σ).

In the broader global context, the U.S. is not a heat island amidst a cooler globe. The warmth is worldwide. The last cool monthly global land and sea anomaly occurred in February 1994 on GISS and February 1985 on the NCDC dataset. The last cool annual anomaly occurred in 1976 on both the GISS and NCDC datasets.

The data are unambiguous and unanimous: the global climate has warmed and the U.S. climate has, too.

If the contrarians e.g., those cited above, as distinguished from those who are more cautious on account of nuance i.e., uncertainties especially non-temperature-related ones, feedback issues that remain to be resolved, complexity of interactions between natural and anthropogenic forcings, are to gain credibility they need to resolve a number of issues.

1. They must find a new natural forcing or some combination of natural factors that allows them to recreate the climate record since the mid-20th century when the explanatory power of natural forcings declined. They need to find another variable or set of variables that allows them to explain the climate evolution at least as well as it is explained when anthropogenic forcings (CO2) are incorporated. In a June 2012 Journal of Climate paper, Gerald A. Meehl et al., found "little net warming" over the 1975-2005 period from "natural forcings only." Moreover, the warming during recent decades cannot be accounted for when anthropogenic factors are excluded.

2. They must find an explanation for the abrupt and dramatic reversal in the millennial scale decline in Arctic temperatures that was being driven by orbital forcings. As there is no evidence that the Atlantic Multidecadal Oscillation (AMO) has radically changed, the AMO cannot explain the dramatic shift that more than counters slowly declining summer solar insolation. Consistent with the need to find a new mechanism or set of mechanisms to explain Arctic trends, the AMO has been found to play a role, but not the leading one, with respect to declining summer Arctic sea ice extent.

3. They must find an explanation for the large expansion of extreme temperature anomalies (3σ or more) that has occurred in recent years. Such anomalies once covered an average of 0.1% to 0.2% of the globe during summers. They now cover around 10%. Synoptic patterns and natural cycles continue to play out. As synoptic patterns and oceanic cycles continue to play out as they have in the past e.g., the PDO-AMO link to drought has led to just such an outcome in the U.S., they need to explain why such expansive areas of extremes are only now occurring.

To date, they have not done so. Rather, they have focused their attacks on the temperature record, arguing that the record has been "manipulated" to create the illusion of rising temperatures. Yet, if temperature adjustments were mainly the basis for the recorded rise in temperatures, one would find a relatively stable response from nature. Aside from declining summer sea ice extent in the Arctic, one finds a lengthening of growing seasons, northward shift in winter nesting ranges for birds, shortening duration of lake ice, and northward shift in plant hardiness zones, general landcover change, and general retreat of glaciers. The warming is real. It is not an artificial construct of temperature adjustments.

Finally, there is a fingerprint of an ongoing energy imbalance that will continue to lead to additional warming. One finds a continuing increase in oceanic heat content (OHC), which shows up at the 0-700m and 0-2000m depths. The increase in OHC is consistent with greenhouse gas forcing.

In the end, the contrarians (Watts, Goddard, Bastardi, et al.,) face a steep challenge of developing a credible explanation for the evolution of the global climate record, namely the long-term warming that has been ongoing and is especially evident when internal variability is accounted for. To date, they have failed to do so. Given nature's consistent response with a warming climate, their current line of attack in seeking to discredit the temperature record lacks credibility. Their trial balloon of a possible new line of attack that denies a radiative forcing for CO2 is inconsistent with basic physics.

At this point in time, the anthropogenic forcing is the best explanation science has to offer for the climate evolution. Even as there remain residual uncertainties and the interaction between anthropogenic forcings and natural forcings/natural oceanic cycles/synoptic patterns is highly complex, the scientific basis is both credible and robust. As such, synoptic patterns and natural oceanic cycles are playing out in the context of natural and anthropogenic forcings, whereas the latter forcing has had growing relative influence due to a continuing rise in atmospheric CO2. Anthropogenic forcing is now the dominant forcing. To date, no credible alternative has been introduced, much less survived the scientific peer review process. Such an alternative, to be credible, will need to address at least the above three issues.

[dabize]

Thank you, Don.

IMHO, this post, from a universally respected met on AmWx, should be the point of departure for conversations here.

It should not be necessary to take statements such as "the global temperature has not risen at all in the past 15 years" seriously anymore, let alone the paranoid tinfoil hat stuff about data manipulation and the pecuniary motivations of climate scientists.

[ORH_wxman]

The July 2012 record is likely legit...if it turns out it isn't in subsequent analysis, we are only talking tenths which is an academic point only.

[donsutherland1]

Just so it is clear, I do not group LEK, ORH_wxman, Coastalwx, among others, with the contrarians to whom I'm referring. I'm referring to individuals and bloggers who take an uncompromising and inflexible stance when it comes to considering the data and its implications.

[donsutherland1]

The July 2012 record is likely legit...if it turns out it isn't in subsequent analysis, we are only talking tenths which is an academic point only.

I agree. I thought we'd finish in the top 3-5 months, so a revision somewhat higher or somewhat lower won't make much difference. The month was exceptionally warm no matter the final outcome.

[WeatherRusty]

Thanks for this clearly explained position which should resound on any rationally thinking person capable of processing the logic contained within.

However, the contrarians are not interested in convincing the rational mind, they play to the psychology of uncertainty and doubt. It is a winning strategy, based on the power suggestion which dominates our trust in reason, particularly for the vast majority of folks who lack sufficient scientific background to put all the logical pieces together.

In short, the contrarians don't have to address any of your points to make their case.

[LakeEffectKing]

With the NOAA reporting that July 2012 eclipsed July 1936 to become the warmest month ever recorded in the contiguous U.S., those taking the minority contrarian position on climate change launched a full-scale attack in the blogosphere. Anthony Watts dismissed the record, writing that the U.S. temperature record results from "a mishmash of urban, semi-urban, rural, airport and non-airport stations, some of which are sited precariously in observers backyards, parking lots, near air conditioner vents, airport tarmac, and in urban heat islands." The Goddard blog charged that "NCDC Tampers With July Data For Global Warming Propaganda Purposes" and that "July 1936 was much hotter." Going even farther, Weatherbell meteorologist Joe Bastardi retweeted a message alleging that a new experiment demonstrated that CO2 has no radiative forcing properties.

In general, if one seeks to prove or disprove a hypothesis, one undertakes an objective examination of the data. Based on that data, one reaches one's conclusions.

Don, in a most respectful way, I disagree with the bolded above, and it is the genisis for, IMO, much of the skeptisism from non-oil paid hacks.

In general, a hypothesis is proved or disproved by pass/fail testability experiments. Objective examinations of data/observations should be done prior to setting up such experiments to test the hypothesis. The specific aspect of the AGW hypothesis dealing with specific global temperature correlations cannot be standardized....thus cannot be tested in any valuable sense. The hypothesis of AGW (wrt specific temperature cause and effects and all other secondary effect assupmptions) are, by the strictest interpretation of the Scientific Method, mired/stuck in the data assimilation/interpretation step, with no real ability to directly test the hypothesis.

Can inferences be drawn without testing?? Sure, but let's first draw the distinction between an inference and a conclusion. In a nutshell, an inference = educated guess and a conclusion is derived from fact or a collection thereof. Conclusions are thusly more conclusive!

And I believe that is where the largest divide resides within the spectrum of opinions on the AGW hypothesis, generally speaking. Some hold more value in the inferences drawn, some don't. True skeptics don't rule out many of the aspects that make up the hypothesis, however, the value ascribed to the inferences, varies.

BTW, you are the epitome of class as has always been the case...whether in agreement or not.

[LakeEffectKing]

The July 2012 record is likely legit...if it turns out it isn't in subsequent analysis, we are only talking tenths which is an academic point only.

Great point. We tend to forget %error when debating this or that year is higher.....Ultimately, the debate is whether there is a headline or not....ie political.

[donsutherland1]

Thanks for this clearly explained position which should resound on any rationally thinking person capable of processing the logic contained within.

However, the contrarians are not interested in convincing the rational mind, they play to the psychology of uncertainty and doubt. It is a winning strategy, based on the power suggestion which dominates our trust in reason, particularly for the vast majority of folks who lack sufficient scientific background to put all the logical pieces together.

In short, the contrarians don't have to address any of your points to make their case.

I was referring strictly to making an effective scientific case.

I wholly agree with you about concerning making the case to the public. As you correctly point out, they see things as sort of a legal case, where if they sow doubt, they win. Hence, they take a classic approach of selecting data that seems to confirm their bias, while ignoring the substantial majority of data that doesn't. They seek to delegitimize the temperature record. They clamor for a political style "debate" with the climate scientists, first to create the perception that they are on "equal footing" with the climate scientists, and second to create the impression that the climate scientists are unwilling and/or unable to back up their conclusions.

They do all this before a public that has a wide range of scientific knowledge (low to high), familiarity with sources of information (low to high), ability to differentiate between weather/meteorology and climate (low to high), among other things. They make their arguments, even as those arguments lack scientific credibility, in a fashion aimed to exploit the public's disparate knowledge, not to mention cognitive biases that we all possess.

[LakeEffectKing]

Thanks for this clearly explained position which should resound on any rationally thinking person capable of processing the logic contained within.

However, the contrarians are not interested in convincing the rational mind, they play to the psychology of uncertainty and doubt. It is a winning strategy, based on the power suggestion which dominates our trust in reason, particularly for the vast majority of folks who lack sufficient scientific background to put all the logical pieces together.

In short, the contrarians don't have to address any of your points to make their case.

The hypothesis has been put forth. It is the duty of scientists to rule out other explainations....if they cannot, there is uncertainty. Whether you want to "box" everyone who believes in that as having malicious intent or not is your perogative.

[Entropy]

Good post, Don. I think legitimate skepticism is good, but some of the cases you cite far exceed legitimate skepticism. Goddard, for instance, has been accusing NCDC and GISS of fraud, claiming they are manipulating data to show a warming trend. This is complete fiction... Goddard cannot, or is unwilling to, grasp the fact that NCDC does not calculate a statewide or national average by simply averaging all of the data in a given state or in the nation. In fact, the NWS has been using climate divisions since the 1950s! I'm pretty sure the motivation for making the switch back then was to better calculate state, regional, and national averages by weighting different climate zones equally, and NOT to create a warming trend. A simple arithmetic mean neglects the fact that some areas are oversampled -- in the case of climate data, particularly in the early years, this was often lower elevation, urban areas -- and also neglects the fact that the location and number of sites has changed over time. A statewide average for Arizona consisting of three sites in and around Phoenix, three sites in and around Tuscon, and fifteen other sites, isn't going to be of much value in a large state with extremely varied geography.

The only adjustments are those disclosed by NCDC. If there is some sort of nefarious purpose, you wouldn't expect them to publish the adjustments on the website. Moreover, BEST found a slightly greater warming trend without those adjustments. BEST used some 7-8,000 U.S. stations, as opposed to the 1,222 USHCN sites, and employed a "scalpel" method that treated site and instrument changes as creating a new station entirely. Unlike NCDC, BEST was not motivated in creating a continuous record, but rather directed towards determining a trend from a large amount of data points, some continuous, some discontinuous. The only adjustment made by BEST was to downweight sites found, by regression, to exhibit an anomalous trend relative to nearby sites.

While Watts is correct that the data may be biased due to the urban heat island effect and siting issues, it is complete fiction to suppose these problems didn't exist in the past. In fact, most city stations used to be cited on rooftops, which have been found to be anomalously warm. Even rural sites did not always conform to specifications, I've seen cases where the shelter was installed only a couple feet above the ground, for instance. Unfortunately, Watts and his team weren't around to document the problems in the past.

Finally, Bastardi has turned into a complete hack. It wasn't too long ago, that he was insisting a major cool down would occur in 2012 and 2013. And I can't even recall the last time, he got a long-range forecast correct. Now it seems he'd rather just post images on Twitter of a six-month JMA forecast showing blue all over the place. And I'm not saying there aren't hacks on the other side (ahem, Romm). But some of this is really silly & somewhat disconcerting, especially Goddard's conspiracy theories.

[LakeEffectKing]

Good post, Don. I think legitimate skepticism is good, but some of the cases you cite far exceed legitimate skepticism. Goddard, for instance, has been accusing NCDC and GISS of fraud, claiming they are manipulating data to show a warming trend. This is complete fiction... Goddard cannot, or is unwilling to, grasp the fact that NCDC does not calculate a statewide or national average by simply averaging all of the data in a given state or in the nation.

They HAVE manipulated data to show a (larger) warming trend....the question is there justification for the manipulation or not....and how confident are they in their adjustments?....and are there more adjustments to come?

[donsutherland1]

Don, in a most respectful way, I disagree with the bolded above, and it is the genisis for, IMO, much of the skeptisism from non-oil paid hacks.

In general, a hypothesis is proved or disproved by pass/fail testability experiments. Objective examinations of data/observations should be done prior to setting up such experiments to test the hypothesis. The specific aspect of the AGW hypothesis dealing with specific global temperature correlations cannot be standardized....thus cannot be tested in any valuable sense. The hypothesis of AGW (wrt specific temperature cause and effects and all other secondary effect assupmptions) are, by the strictest interpretation of the Scientific Method, mired/stuck in the data assimilation/interpretation step, with no real ability to directly test the hypothesis.

Can inferences be drawn without testing?? Sure, but let's first draw the distinction between an inference and a conclusion. In a nutshell, an inference = educated guess and a conclusion is derived from fact or a collection thereof. Conclusions are thusly more conclusive!

And I believe that is where the largest divide resides within the spectrum of opinions on the AGW hypothesis, generally speaking. Some hold more value in the inferences drawn, some don't. True skeptics don't rule out many of the aspects that make up the hypothesis, however, the value ascribed to the inferences, varies.

BTW, you are the epitome of class as has always been the case...whether in agreement or not.

LEK,

You make a fair point. Sometimes, unfortunately, there are limits to testability outside a laboratory setting. One sees examples of this in theoretical physics where models and math are deployed to try to explain largely untestable phenomena. Neverthless, notable attempts are underway to work within those limits e.g., at CERN.

Attribution science, still in its infancy and still largely statistics-based, is a fairly recent attempt to begin to try to examine the contribution made by climate change as it relates to specific events. Much more work remains to be done on that end and examples of differing conclusions on such matters as the 2010 heat wave in Russia by respectable scientists (Dr. Hoerlich on one end seeing largely natural causes and Dr. Rahmstorm seeing a more significant contribution from climate change) can be expected until attribution methodologies become more advanced. I'm not sure one will ever be able to conclude X event was definitely the result of climate change, but one might reach the level of confidence to be able to say that it was "very likely" or maybe even "extremely likely" the result of climate change.

Overall, the outcome of the temperature record is what one should reasonably expect from the scientific understanding of climate change. To date, the AGW explanation offers the strongest fit to the evolution of the climate, especially from the mid-20th century on, even as some degree of uncertainty exists.

Finally, your description of true skeptics, as opposed to the contrarians to whom I'm referring, fall within the context of those who want to narrow some of the areas of uncertainty. They fall within the scientific framework.

In contrast, the contrarians have taken a position on faith/ideology alone--their faith/ideology that it is not possible for humans to impact the climate--and thus they reject all data that contradicts their faith/ideology e.g., by seeking to discredit the temperature record and now trying to undermine CO2's properties as a greenhouse gas. That group most definitely does not fall within a scientific framework.

[WeatherRusty]

The hypothesis has been put forth. It is the duty of scientists to rule out other explainations....if they cannot, there is uncertainty. Whether you want to "box" everyone who believes in that as having malicious intent or not is your perogative.

LEK,

You know, or should know, I am not speaking of you or the honest skeptics on this forum. I am referring to the creators of the 'denier playbook'.

[LakeEffectKing]

LEK,

You make a fair point. Sometimes, unfortunately, there are limits to testability outside a laboratory setting. One sees examples of this in theoretical physics where models and math are deployed to try to explain largely untestable phenomena. Neverthless, notable attempts are underway to work within those limits e.g., at CERN.

Attribution science, still in its infancy and still largely statistics-based, is a fairly recent attempt to begin to try to examine the contribution made by climate change as it relates to specific events. Much more work remains to be done on that end and examples of differing conclusions on such matters as the 2010 heat wave in Russia by respectable scientists (Dr. Hoerlich on one end seeing largely natural causes and Dr. Rahmstorm seeing a more significant contribution from climate change) can be expected until attribution methodologies become more advanced. I'm not sure one will ever be able to conclude X event was definitely the result of climate change, but one might reach the level of confidence to be able to say that it was "very likely" or maybe even "extremely likely" the result of climate change.

Overall, the outcome of the temperature record is what one should reasonably expect from the scientific understanding of climate change. To date, the AGW explanation offers the strongest fit to the evolution of the climate, especially from the mid-20th century on, even as some degree of uncertainty exists.

Finally, your description of true skeptics, as opposed to the contrarians to whom I'm referring, fall within the context of those who want to narrow some of the areas of uncertainty. They fall within the scientific framework.

In contrast, the contrarians have taken a position on faith/ideology alone--their faith/ideology that it is not possible for humans to impact the climate--and thus they reject all data that contradicts their faith/ideology e.g., by seeking to discredit the temperature record and now trying to undermine CO2's properties as a greenhouse gas. That group most definitely does not fall within a scientific framework.

You sure can bridge gaps! It is unfortunate that the discorse gets heated at times with individuals to the point of anger and virtual hatred. Nobody likes to be labeled a "warmist" or a "denier", and that seems to be the trigger which inflames solid debate. We all have "temper" thresholds (except you! ) and occasionally reposition ourselves within a debate (ie take sides) just on emotion alone. It is the process of science, and hopefully, the politics can be scrubbed out (difficult) and the uncertainties addressed in the manner which you've laid out. After all, we all want a "nice clean world" for our future generations.

[donsutherland1]

They HAVE manipulated data to show a (larger) warming trend....the question is there justification for the manipulation or not....and how confident are they in their adjustments?....and are there more adjustments to come?

The data clearly has been adjusted/homogenized, and the adjusted data shows more of a warming trend than the raw data.

The literature suggests that the adjustments do not create an unreliable temperture record. One paper can be found at:

ftp://ftp.ncdc.noaa.gov/pub/data/ushcn/v2/monthly/williams-menne-thorne-2012.pdf

Perhaps just as important, nature's response seems to suggest that the adjusted data better fits the actual climatic evolution than the raw data (e.g., Goddard has alternately argued that the U.S. climate is not warming and perhaps even cooling based on raw data alone). Needless to say, some residual error almost certainly exists and almost certainly cannot be eliminated. A reasonably accurate representation of the climate is probably the best one can hope for.

[LakeEffectKing]

LEK,

You know, or should know, I am not speaking of you or the honest skeptics on this forum. I am referring to the creators of the 'denier playbook'.

I'm not always sure...it's hard to tell sometimes (and the line moves as heated debate/discussions take place) what is an honest skeptic........I don't place as much value in this so-called "denier-playbook" as you do....but then again, I'm not as threatened by such.

Honestly, as much as I am "honestly" skeptical of some of the conclusions drawn wrt the AGW hypothesis, I can't rule out that ideology doesn't impact/skew/bias my view....and I think if everyone did a little introspective browsing, they may be able to find that small crack within themselves that admits to ideological bias messing with objectivity..it's not easily quatifiable within ones' self....and that is especially true when we are trying to answer scientific questions with interpretable data, but lack the specific ability to perform objective testing on said hypothesis.....ie the presence of some uncertainty..

[LakeEffectKing]

The data clearly has been adjusted/homogenized, and the adjusted data shows more of a warming trend than the raw data.

The literature suggests that the adjustments do not create an unreliable temperture record. One paper can be found at:

ftp://ftp.ncdc.noaa.gov/pub/data/ushcn/v2/monthly/williams-menne-thorne-2012.pdf

Perhaps just as important, nature's response seems to suggest that the adjusted data better fits the actual climatic evolution than the raw data (e.g., Goddard has alternately argued that the U.S. climate is not warming and perhaps even cooling based on raw data alone). Needless to say, some residual error almost certainly exists and almost certainly cannot be eliminated. A reasonably accurate representation of the climate is probably the best one can hope for.

How do we completely rule out the possibility of confirmation bias? It is not an unreasonable question to ask when you see the pattern of adjustments over the historical temerature data set. I know the methodologies for the adjustments are sound, but if there is no real way of determining if the % error has been reduced, then can we really state that the adjusted record is more reliable than the previous version?

If one wanted to created a buzz on the "other side" then performing a series of adjustments during a "slowing" of the global atmospheric temperatures sure does the trick!

[donsutherland1]

I know the methodologies for the adjustments are sound, but if there is no real way of determining if the % error has been reduced, then can we really state that the adjusted record is more reliable than the previous version?

There are probably limits to quantifying the improvement, but considering that the raw data would imply much less warming than the adjusted data and nature's changes consistent with warming suggests that the latter is probably closer to the actual outcome than the raw data. How much closer? That's difficult to measure precisely, but it almost certainly is a more reasonable approximation than the raw data suggesting little or no change in national temperatures.

[ben4vols]

So to sum up...you're saying you have this hypothesis and you can't prove it is true so you are throwing it on the shoulders of others to prove it isn't?

[dabize]

Just so it is clear, I do not group LEK, ORH_wxman, Coastalwx, among others, with the contrarians to whom I'm referring. I'm referring to individuals and bloggers who take an uncompromising and inflexible stance when it comes to considering the data and its implications.

Understood, and I didn't mean to imply that you should - not at all.

[ben4vols]

They HAVE manipulated data to show a (larger) warming trend....the question is there justification for the manipulation or not....and how confident are they in their adjustments?....and are there more adjustments to come?

A bigger point of contention for me is the Arctic manipulation. That manipulation alone adds a large degree of warming to the signal. There is no justification that I have seen that is agreeable for what they did to past Arctic temps. 20 of 23 stations were adjusted in the same fashion. Some against the wishes of those who have overseen the stations and the integrity of the station data.

[PhillipS]

So to sum up...you're saying you have this hypothesis and you can't prove it is true so you are throwing it on the shoulders of others to prove it isn't?

A hypothesis, or theory, can't be 'proved' - that's a term more appropriate for mathematics. A hypothesis is tested against the data and the data either corroborates the hypothesis or falsifies it.

In the case of the set of theories making up mainstream AGW - the data records corroboates the theories.

[ben4vols]

2. They must find an explanation for the abrupt and dramatic reversal in the millennial scale decline in Arctic temperatures that was being driven by orbital forcings. As there is no evidence that the Atlantic Multidecadal Oscillation (AMO) has radically changed, the AMO cannot explain the dramatic shift that more than counters slowly declining summer solar insolation. Consistent with the need to find a new mechanism or set of mechanisms to explain Arctic trends, the AMO has been found to play a role, but not the leading one, with respect to declining summer Arctic sea ice extent.

I disagree with this point Don. Although it has been discussed in the Arctic Ice thread. You are basing your judgement on a paper that is comparing results today with modeled results in the past. There is no way to know if the modeled data of the past is anywhere close to being accurate. We have crude drawings from the early 1900's depicting ice area and extent. No where close the the more accurate data we have now. What was the ice thickness when the last +AMO started in and around 1919? Is the AMO number from that time period as reliable as the numbers we have today? Being even a little off on modeling the past could make huge changes in how the AMO is perceived to influence the Arctic.

[PhillipS]

A bigger point of contention for me is the Arctic manipulation. That manipulation alone adds a large degree of warming to the signal. There is no justification that I have seen that is agreeable for what they did to past Arctic temps. 20 of 23 stations were adjusted in the same fashion. Some against the wishes of those who have overseen the stations and the integrity of the station data.

Please provide some evidence to support that claim.

[ben4vols]

Also Don, you mention the Arctic but you don't mention the Antarctic which has actually been gaining ice over the last 30 years.

[ORH_wxman]

I disagree with this point Don. Although it has been discussed in the Arctic Ice thread. You are basing your judgement on a paper that is comparing results today with modeled results in the past. There is no way to know if the modeled data of the past is anywhere close to being accurate. We have crude drawings from the early 1900's depicting ice area and extent. No where close the the more accurate data we have now. What was the ice thickness when the last +AMO started in and around 1919? Is the AMO number from that time period as reliable as the numbers we have today? Being even a little off on modeling the past could make huge changes in how the AMO is perceived to influence the Arctic.

There is no peer reviewed evidence as of now that supports we had the same temperatures in the arctic during the last AMO+ phase. It is almost certainly warmer during this AMO+ phase than the last one.

That does not mean the AMO does not provide a significant contribution on a multidecadal time scale to arctic temperatures though. It clearly has looking at the late 30s/early 40s peak, then subsequent dip and then rising again. The question is how much affect will the next AMO- phase have on the temperatures. If the external forcing is getting larger and larger as to overpower the natural cycles and reduce their significance, then we would expect arctic temperatures to continue to rise when we flip to AMO- sometime in the 2020s. We'll just have to wait and see.

On a larger scale, this is what we will be waiting to observe globally over the next couple decades...whether the recent slowdown is just a small sample size fluke or if the PDO/ENSO multidecadal cycle has the ability to slow the temperature rise in comparison to the 1975-2000 time frame.

[LakeEffectKing]

There is no peer reviewed evidence as of now that supports we had the same temperatures in the arctic during the last AMO+ phase. It is almost certainly warmer during this AMO+ phase than the last one.

That does not mean the AMO does not provide a significant contribution on a multidecadal time scale to arctic temperatures though. It clearly has looking at the late 30s/early 40s peak, then subsequent dip and then rising again. The question is how much affect will the next AMO- phase have on the temperatures. If the external forcing is getting larger and larger as to overpower the natural cycles and reduce their significance, then we would expect arctic temperatures to continue to rise when we flip to AMO- sometime in the 2020s. We'll just have to wait and see.

On a larger scale, this is what we will be waiting to observe globally over the next couple decades...whether the recent slowdown is just a small sample size fluke or if the PDO/ENSO multidecadal cycle has the ability to slow the temperature rise in comparison to the 1975-2000 time frame.

If I recall correctly, didn't the NSIDC or NOAA come out with a statement/paper suggesting that ice extent would stabilize for a few decades??? I think it was a couple years ago....

[PhillipS]

Also Don, you mention the Arctic but you don't mention the Antarctic which has actually been gaining ice over the last 30 years.

You need to be careful to distinguish between the Antarctic ice sheet, which has been losing mass, and the antarctic sea ice which has slowly gained area during the instrumental record. A chart from the NASA webpage on this:

And one from NSIDC:

You know, if you did these simple google searches yourself you would appear much better informed.

[ben4vols]

There is no peer reviewed evidence as of now that supports we had the same temperatures in the arctic during the last AMO+ phase. It is almost certainly warmer during this AMO+ phase than the last one.

That does not mean the AMO does not provide a significant contribution on a multidecadal time scale to arctic temperatures though. It clearly has looking at the late 30s/early 40s peak, then subsequent dip and then rising again. The question is how much affect will the next AMO- phase have on the temperatures. If the external forcing is getting larger and larger as to overpower the natural cycles and reduce their significance, then we would expect arctic temperatures to continue to rise when we flip to AMO- sometime in the 2020s. We'll just have to wait and see.

On a larger scale, this is what we will be waiting to observe globally over the next couple decades...whether the recent slowdown is just a small sample size fluke or if the PDO/ENSO multidecadal cycle has the ability to slow the temperature rise in comparison to the 1975-2000 time frame.

The temps during this +AMO phase could certainly be warmer than the last in the Arctic although according to unadjusted temperature record from the Arctic stations it is close. Also the warming during this phase looks to be of longer duration vs the last. This would be expected though especially if there was more ice to melt in the last +AMO period vs this period. Which is my point of contention with Don's study he linked. Small changes in modeled ice from the past (around 1919) could have large impacts and completely invalidate the study. What was the inflow of Atlantic Water during the last +AMO phase (starting in 1919)?