IPCC Report is Released

[donsutherland1]

Today, the Intergovernmental Panel on Climate Change (IPCC) released its summary report for policymakers. The report confirms the role human activities have played in driving climate change. Excerpts from the accompanying press release:

 

Human influence on the climate system is clear. This is evident in most regions of the globe... It is extremely likley that human influence has been the dominant cause of the observed warming since the mid-20th century...Warming in the climate system is unequivocal and since 1950 many changes have been observed throughout the climate system that are unprecedented over decades to millennia.

 

The Summary for Policymakers was released today and can be found at: http://www.climatechange2013.org/images/uploads/WGIAR5-SPM_Approved27Sep2013.pdf

 

The full report (unedited) will be released on September 30 and will be available at: http://www.ipcc.ch/report/ar5/wg1/

 

 

[WXheights]

We all await the Poo-poo Committee

[ORH_wxman]

We all await the Poo-poo Committee

 

 

The summary for policy makers isn't that interesting to those of us who read a lot of papers since they try and dumb it down for the politicians (which makes sense since politicians review it before it's released). Unfortunately they gloss over a lot of the uncertainty in climate science in their SPM report that the full report goes into more detail in. They do imply more uncertainty though in that they no longer give a "best estimate" or "most likely" estimate for climate sensitivity like they used to do. They simply give a range...a range wider than the old range from AR4.

 

You have to go down to the footnotes at the bottom to learn more:

 

 No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies.

[Snow_Miser]

The summary for policy makers isn't that interesting to those of us who read a lot of papers since they try and dumb it down for the politicians (which makes sense since politicians review it before it's released). Unfortunately they gloss over a lot of the uncertainty in climate science in their SPM report that the full report goes into more detail in. They do imply more uncertainty though in that they no longer give a "best estimate" or "most likely" estimate for climate sensitivity like they used to do. They simply give a range...a range wider than the old range from AR4.

You have to go down to the footnotes at the bottom to learn more:

No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies.

That's a really interesting quote. In other words, the skeptics were right in saying that sensitivity was not as constrained as AR4 depicted it to be. The science on ECS is far from settled, and more uncertain than ever before.

[Jonger]

 

 No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies.

Which is the entire debate in a nutshell.

[ben4vols]

You have to go down to the footnotes at the bottom to learn more:

 

 No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies.

 

Well it is a baby step in the right direction.  So much for consensus and settle science bull crap.  The climate alarmists will throw themselves in a wind turbine if they one day have to admit that Dr. Spencer (and others) were right. 

[PhillipS]

Well it is a baby step in the right direction.  So much for consensus and settle science bull crap.  The climate alarmists will throw themselves in a wind turbine if they one day have to admit that Dr. Spencer (and others) were right. 

 

Why do you interpret the statement to mean that climate sensitivity is lower than the earlier IPCC report?  From everything I've seen, they are acknowledging that the bounds are broader than past estimates - something interesting but not earthshaking.  A "best estimate" value for ECS depends on the probability distribution function (PDF), i.e. the shape of the curve describing the range of possible ECS values.  We've known for a long time that the PDF is not a classic bell curve but rather an asymmetric curve with a long tail towards higher ECS values. So, to me, the IPCC statement just means that there is no agreement on the ECS PDF.

[Jonger]

There used to be a joke on one of our local radio stations by a guy called the Bruiser. When the forecast was for 6-12 inches, he would take the 6 inch number, cut it in half and reissue the forecast with "The Bruiser effect" giving us a 3 inch storm prediction. It was actually right half the time, considering this was the 1980's and models weren't as good.

Well I would like to use the Bruiser model on the ECS. It has worked over the past 4 IPCC reports, why not 5.

[Snow_Miser]

Why do you interpret the statement to mean that climate sensitivity is lower than the earlier IPCC report?  

 

It doesn't mean it's lower, but it means it's more uncertain than before, and that it has acknowledged many papers in recent years within the 1-2 Degree C range for ECS. Roy Spencer and Danny Braswell have a paper in press that finds ECS to be 1.3 Degrees C, within this range of lower climate sensitivity estimates. Skeie et al. 2013 found an ECS of 1.8 Degrees C. Ring et al. found a sensitivity anywhere from 1.5-2.0 Degrees C. Bogdanov et al. 2012 found a sensitivity of 1.5 Degrees C. The IPCC is acknowledging such lower estimates in their report. Pretty amazing how some claim the science is settled, when it is blindingly obvious that there are large unknowns, and our estimates of ECS are poorly constrained.

[tacoman25]

Why do you interpret the statement to mean that climate sensitivity is lower than the earlier IPCC report?  From everything I've seen, they are acknowledging that the bounds are broader than past estimates - something interesting but not earthshaking.  A "best estimate" value for ECS depends on the probability distribution function (PDF), i.e. the shape of the curve describing the range of possible ECS values.  We've known for a long time that the PDF is not a classic bell curve but rather an asymmetric curve with a long tail towards higher ECS values. So, to me, the IPCC statement just means that there is no agreement on the ECS PDF.

 

The range has trended lower. You'd have to be blind not to see that.

[skierinvermont]

Well it is a baby step in the right direction.  So much for consensus and settle science bull crap.  The climate alarmists will throw themselves in a wind turbine if they one day have to admit that Dr. Spencer (and others) were right. 

 

The new IPCC report still rules out an ECS as low as Spencer's pseudo-science would have you believe. A climate sensitivity that low can probably be ruled out with near 99% confidence.

[skierinvermont]

It doesn't mean it's lower, but it means it's more uncertain than before, and that it has acknowledged many papers in recent years within the 1-2 Degree C range for ECS. Roy Spencer and Danny Braswell have a paper in press that finds ECS to be 1.3 Degrees C, within this range of lower climate sensitivity estimates. Skeie et al. 2013 found an ECS of 1.8 Degrees C. Ring et al. found a sensitivity anywhere from 1.5-2.0 Degrees C. Bogdanov et al. 2012 found a sensitivity of 1.5 Degrees C. The IPCC is acknowledging such lower estimates in their report. Pretty amazing how some claim the science is settled, when it is blindingly obvious that there are large unknowns, and our estimates of ECS are poorly constrained.

 

You are lumping in some legitimate scientific studies pointing at the 1.5-2.5 range with pseudo-scientific nonsense studies that claim lower than 1.5C. The lack of evidence or reason in the latter studies is why they have not been accepted by the vast majority of climate scientists, and why the IPCC still sets the lowest threshold at 1.5C.

 

I don't think there are any rigorous studies actually arguing that it is 1.5C. The lowest I've seen is ~2C with confidence ranges that encompass 1.5C. No rigorous studies argue that climate sensitivity is most likely 1.5C. 

 

Although the IPCC declined to give a most likely value or range, it would probably be 2.5-3C. 

 

A climate sensitivity of 1.5C remains as likely as a climate sensitivity of 4.5C. Both are highly unlikely.

[Snow_Miser]

You are lumping in some legitimate scientific studies pointing at the 1.5-2.5 range with pseudo-scientific nonsense studies that claim lower than 1.5C. The lack of evidence or reason in the latter studies is why they have not been accepted by the vast majority of climate scientists, and why the IPCC still sets the lowest threshold at 1.5C.

 

I don't think there are any rigorous studies actually arguing that it is 1.5C. The lowest I've seen is ~2C with confidence ranges that encompass 1.5C. No rigorous studies argue that climate sensitivity is most likely 1.5C. 

 

Although the IPCC declined to give a most likely value or range, it would probably be 2.5-3C. 

 

A climate sensitivity of 1.5C remains as likely as a climate sensitivity of 4.5C. Both are highly unlikely.

 

This is what the Summary for Policymakers has to say about Climate Sensitivity:

 

"The equilibrium climate sensitivity quantifies the response of the climate system to constant radiative forcing on multi-century time scales. It is defined as the change in global mean surface temperature at equilibrium that is caused by a doubling of the atmospheric CO2 concentration. Equilibrium climate sensitivity is likely in the range 1.5°C to 4.5°C (high confidence), extremely unlikely less than 1°C (high confidence), and very unlikely greater than 6°C (medium confidence)."

 

The IPCC also "declined to give a most likely value" because of this:

 

"No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies."

 

No where does it say that 1.5 Degrees C is an implausible sensitivity, and this latest report would seem to suggest that a 1.5 Degree C sensitivity is more plausible than before, given that they lowered the lower end of their most likely range from 2 Degrees C to 1.5 Degrees C.

 

It does say that it is not plausible for there to be a sensitivity lower than 1 Degree C.

 

Where do you draw the line between what you consider to be rigorous scientific studies and "nonsense studies?" If a study finds an ECS around 1.4 Degrees C instead of 1.5 Degrees C, does that make one paper a nonsense study, and the other a legitimate study? That's nonsensical.

[PhillipS]

From the report:

 

D.2 Quantification of Climate System Responses 

Observational and model studies of temperature change, climate feedbacks and changes in the 

Earth’s energy budget together provide confidence in the magnitude of global warming in response 

to past and future forcing. {Box 12.2, Box 13.1} 

 

• The net feedback from the combined effect of changes in water vapour, and differences 

between atmospheric and surface warming is extremely likely positive and therefore amplifies 

changes in climate. The net radiative feedback due to all cloud types combined is likely

positive. Uncertainty in the sign and magnitude of the cloud feedback is due primarily to 

continuing uncertainty in the impact of warming on low clouds. {7.2} 

• The equilibrium climate sensitivity quantifies the response of the climate system to constant 

radiative forcing on multi-century time scales. It is defined as the change in global mean 

surface temperature at equilibrium that is caused by a doubling of the atmospheric CO2

concentration. Equilibrium climate sensitivity is likely in the range 1.5°C to 4.5°C (high 

confidence), extremely unlikely less than 1°C (high confidence), and very unlikely greater than 

6°C (medium confidence).   The lower temperature limit of the assessed likely range is thus 

less than the 2°C in the AR4, but the upper limit is the same. This assessment reflects 

improved understanding, the extended temperature record in the atmosphere and ocean, and 

new estimates of radiative forcing. {TFE6.1, Figure 1; Box 12.2} 

• The rate and magnitude of global climate change is determined by radiative forcing, climate 

feedbacks and the storage of energy by the climate system. Estimates of these quantities for 

recent decades are consistent with the assessed likely range of the equilibrium climate

sensitivity to within assessed uncertainties, providing strong evidence for our understanding of 

anthropogenic climate change. {Box 12.2, Box 13.1} 

• The transient climate response quantifies the response of the climate system to an increasing 

radiative forcing on a decadal to century timescale. It is defined as the change in global mean 

surface temperature at the time when the atmospheric CO2 concentration has doubled in a 

scenario of concentration increasing at 1% per year. The transient climate response is likely in 

the range of 1.0°C to 2.5°C (high confidence) and extremely unlikely greater than 3°C. {Box 

12.2} 

• A related quantity is the transient climate response to cumulative carbon emissions (TCRE). It 

quantifies the transient response of the climate system to cumulative carbon emissions (see 

Section E.8). TCRE is defined as the global mean surface temperature change per 1000 GtC 

emitted to the atmosphere. TCRE is likely in the range of 0.8°C to 2.5°C per 1000 GtC and 

applies for cumulative emissions up to about 2000 GtC until the time temperatures peak (see 

Figure SPM.9). {12.5, Box 12.2} 

 

The bolding is mine.  The ECS value is likely in the range of 1.5C to 4.5C - which means it is equally likely to be either end of the range.  As I mentioned in my earlier post the PDF curve is asymmetric and we can see that in the bounding values outside the "likely" range.  It is extremely unlikely that the ECS is below 1C and the report give that with high confidence - but the authors are not as sure about the upper bound - the report says that the ECS is very unlikely to be above 6C but they only say that with medium confidence. 

 

To clarify those terms I copied these definitions from the 2007 IPCC report:

 

Likelihood Terminology  Likelihood of the occurrence/ outcome  

Virtually certain  > 99% probability 

Extremely likely  > 95% probability  

Very likely  > 90% probability 

Likely  > 66% probability 

More likely than not  > 50% probability 

About as likely as not  33 to 66% probability 

Unlikely  < 33% probability 

Very unlikely  < 10% probability 

Extremely unlikely  < 5% probability 

Exceptionally unlikely  < 1% probability 

 

Confidence Terminology  Degree of confidence in being correct 

Very high confidence  At least 9 out of 10 chance  

High confidence  About 8 out of 10 chance 

Medium confidence  About 5 out of 10 chance 

Low confidence  About 2 out of 10 chance 

Very low confidence  Less than 1 out of 10 chance 

[blizzard1024]

You are lumping in some legitimate scientific studies pointing at the 1.5-2.5 range with pseudo-scientific nonsense studies that claim lower than 1.5C. The lack of evidence or reason in the latter studies is why they have not been accepted by the vast majority of climate scientists, and why the IPCC still sets the lowest threshold at 1.5C.

 

I don't think there are any rigorous studies actually arguing that it is 1.5C. The lowest I've seen is ~2C with confidence ranges that encompass 1.5C. No rigorous studies argue that climate sensitivity is most likely 1.5C. 

 

Although the IPCC declined to give a most likely value or range, it would probably be 2.5-3C. 

 

A climate sensitivity of 1.5C remains as likely as a climate sensitivity of 4.5C. Both are highly unlikely.

 

What determines what a legitimate study is vs. a "pseudo" study? If it agrees with your scientific viewpoints?  

[skierinvermont]

SL+blizzard1024,

 

A legitimate scientific study is one that has been rigorously peer-reviewed, is generally accepted or at least not viewed as containing major flaws by fellow members of the field, and would likely be included in any comprehensive summary of the subject (such as the IPCC report). 

 

Often papers not meeting these qualifications contain glaring errors that even a discerning lay-person can recognize, as has been the case with many of the papers SL has posted on this forum and fraudulently claimed are "peer-reviewed."

[Snow_Miser]

Often papers not meeting these qualifications contain glaring errors that even a discerning lay-person can recognize, as has been the case with many of the papers SL has posted on this forum and fraudulently claimed are "peer-reviewed."

You've made this claim multiple times, and yet have never backed it up with examples.

I think I've posted an article once or twice that I thought was peer reviewed, but I was mistaken and admitted it afterwards.

Of course, skier has made similar mistakes as well on this forum.

[Snow_Miser]

What determines what a legitimate study is vs. a "pseudo" study? If it agrees with your scientific viewpoints?

Skier has a habit of dismissing anything that disagrees with him as a pseudoscientific journal or article. He also has a habit of claiming that any observation published in peer reviewed science that disagrees with his viewpoint is manipulated, fudged, and made up.

[blizzard1024]

SL+blizzard1024,

 

A legitimate scientific study is one that has been rigorously peer-reviewed, is generally accepted or at least not viewed as containing major flaws by fellow members of the field, and would likely be included in any comprehensive summary of the subject (such as the IPCC report). 

 

Often papers not meeting these qualifications contain glaring errors that even a discerning lay-person can recognize, as has been the case with many of the papers SL has posted on this forum and fraudulently claimed are "peer-reviewed."

"rigorously peer-reviewed" by  "fellow members of the field".... that is the problem in my opinion.  

[Sickman]

"rigorously peer-reviewed" by "fellow members of the field".... that is the problem in my opinion.

With all due respect, if you're discrediting the entire peer review process, on what can you base any theory or opinion?

[Mallow]

With all due respect, if you're discrediting the entire peer review process, on what can you base any theory or opinion?

 

This.

 

That's how science works. All science. How is a peer review by someone with little knowledge of the specific subject in question helpful?

[Jonger]

This.

 

That's how science works. All science. How is a peer review by someone with little knowledge of the specific subject in question helpful?

 

Most science fields aren't political, at least not as much as climate science. Nobody questions the peer review process for biologists in 2013, changes in biology rarely come out with reports saying we are all doomed, or have to change our way of life. Climate science is split right down party lines even within our own country, people reject findings or embrace them based on how their political leanings.

 

Trying to claims there is no bias one way or another is just silly.

[DeltaPilot]

Where EXACTLY is that quote found in the summary and are they refering to human values or temp change values/forcing? I cant seem to locate it and I am having a discussion about this exact quote on another forum.  I understand the IPCC uses the "value" term for things such as human value in different parts of the world, but it sure appears to me they are talking about something else here.

[Snow_Miser]

Where EXACTLY is that quote found in the summary and are they refering to human values or temp change values/forcing? I cant seem to locate it and I am having a discussion about this exact quote on another forum. I understand the IPCC uses the "value" term for things such as human value in different parts of the world, but it sure appears to me they are talking about something else here.

What quote are you referring to?

[Jonger]

it sounds persuasive...if you don't know anything about the medical field.

http://www.economist.com/node/21528593

http://scholarlykitchen.sspnet.org/2011/01/17/when-fraud-hits-medical-science-the-decade-of-the-vaccine-autism-scandal/

http://www.bioethics.net/2009/05/merck-makes-phony-peerreview-journal/

http://www.pbs.org/newshour/bb/science/july-dec05/scandal_12-27.html

http://www.labtimes.org/editorial/e_136.lasso

http://ethicalnag.org/2010/11/08/linda-buck-retracts-articles/

 

Of course there are push-backs and controversially studies, but typically these aren't debated by the public or are driven down political lines. 

[DeltaPilot]

was talking about this.......

 

No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies.

[ORH_wxman]

was talking about this.......

 

No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies.

 

 

Page SPM-11 at the bottom is the footnote

 

 

http://www.climatechange2013.org/images/uploads/WGIAR5-SPM_Approved27Sep2013.pdf

[PhillipS]

as has been already noted, that is the footnote for the bolded line in Phillip's quote. the section he quoted gives you the section and paragraph it is found in.

 

I should have provided the link [link] in my post but I just followed Don's OP on this thread and thought others could do the same if they wanted more details.  My excerpt was from section D2, page SPM-11

[Jonger]

was talking about this.......

 

No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies.

That quote will drive tons of internet bickering for years.

[Snow_Miser]

That quote will drive tons of internet bickering for years.

 

The fact that the IPCC now indicates that there is substantial disagreement among sensitivity estimates.. enough to not issue a most likely estimate is huge. As you put it.. that's the climate debate in a nutshell.