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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Recent Comments

Comments 31401 to 31450:

funglestrumpet at 00:21 AM on 7 February 2015

Claims that climate models overestimate warming are 'unfounded', study shows

I have just endured forty-two minutes and twenty-two seconds of the good Lord spouting forth about his new paper. He gets up to all his usual tricks, such as wearing several layers of clothing while indoors because it is cold outside and therefore global warming is all a hoax. Anyone with the stomache to watch it can find it here: https://www.youtube.com/watch?v=fE7r0gk5nmw (USA Watchdog channel).

He closes with the assertion that if his paper is found to be correct, it will settle the whole issue of whether climate change is real or not. I would like to suggest that the converse is also true. If his paper is found to be incorrect, then by the same token he should accept that such an eventuality proves that it is real and that he should just shut up about the issue. I am not holding my breath! Experience says that no matter how many papers there are like this OP, he will not change his stance. Though there are signs of desperation. He seems to be linking climate change to a socialist/communist conspiracy.

Moderator Response:

[JH] For future reference, we discourage commenters from providing direct links to propaganda pieces produced by Monckton and his ilk.

Warning: Watching a video like the one linked to above can be injurous to your mental health and well-being.

daveburton at 23:23 PM on 6 February 2015

Kevin Cowtan Debunks Christopher Booker's Temperature Conspiracy Theory

To address concerns about comparing data only for the endpoints (1900 & 2014), I went back and used WebPlotDigitizer to digitize a number of intermediate points. I digitized all years ending in "0" so that decadal trends could be calculated starting with year 1900, which is the earliest year in Dr. Cowtan's graph. I also digitized years ending in "4" so that decadal trends could be calculated ending with year 2014, which is the latest year for which data exists. (I didn't include the other years because digitizing all that data is very tedious!)

Using WebPlotDigitizer, I digitized the temperatures for each plot (unadjusted temperatures and adjusted temperatures) for the following years:
1900, 1904, 1910, 1914, 1920, 1924, 1930, 1934, 1940, 1944, 1950, 1954, 1960, 1964, 1970, 1974, 1980, 1984, 1990, 1994, 2000, 2004, 2010, 2014.

(Note: I started over, so some digitized values are very slightly different from the values I previously obtained.)

I loaded all the data into a spreadsheet in Excel, with these column headers:

year unadj_temp adj_temp

I then added ten calculated columns:

adj-unadj = the difference between adjusted and unadjusted temperature.

50yr_unadj_diff = the difference in unadjusted temperatures between the designated year and fifty years earlier. If positive, it indicates warming compared to fifty years earlier; if negative, it indicates cooling.

50yr_adj_diff = the difference in adjusted temperatures between the designated year and fifty years earlier.

50yr_%warm_from_adj = the percentage of the warming which is due to the adjustments, over 50-year intervals, starting with 1900-1950, and ending with 1964-2014. (Percentage is shown as "100%" if the unadjusted data indicated cooling.) The results were:
100.0%, 22.2%, 39.6%, 100.0%, 54.4%, 100.0%, 48.1%, 96.8%, 21.6%, 30.9%, 20.7%, 17.0%, 7.7%, 7.5%.
Note that, over the last 50 years (1964-2014), only 7.5% of the warming is due to adjustments (i.e., the adjustments increased warming by 8.1%). However, of all the 50-year intervals, that interval shows the lowest percentage of warming due to adjustments.

70yr_unadj_diff = the difference in unadjusted temperatures between the designated year and seventy years earlier.

70yr_adj_diff = the difference in adjusted temperatures between the designated year and seventy years earlier.

70yr_%war_from_adj = the percentage of the warming which is due to the adjustments, over 70-year intervals, starting with 1900-1970, and ending with 1944-2014:
89.0%, 43.0%, 28.6%, 75.8%, 23.7%, 27.4%, 35.6%, 27.2%, 16.2%, 15.9%.

114yr_unadj_diff = the difference in unadjusted temperatures between 2014 and 1900 (0.86 °C).

114yr_adj_diff = the difference in adjusted temperatures between 2014 and 1900 (1.16 °C).

114yr_%war_from_adj = the percentage of the warming which is due to the adjustments (26%).

114yr_increase_by_adj = the percentage by which the adjustments increased the reported warming (35%).

I added all these files to my little web page about this argument between Booker and Cowtan:
http://tinyurl.com/cowtan-v-booker

The screenshot files (with and without digitization points added), digitized data files, spreadsheet, WebPlotDigitizer calibration & data file, and notes are all available in a convenient .zip archive, in case you want to check my work or do additional calculations.

One last note: to address Tom Curtis's concern, based on the USHCN adjustments, that the endpoints migh have anomolous adjustments, I used Excel to plot adj-unadj for the 24 years which I digitized. If you download the spreadsheet and load it into Excel, you'll see that it looks like it's almost linearly increasing, though because I digitized only 20% of the years it's obviously incomplete.

bjchip at 22:51 PM on 6 February 2015

Claims that climate models overestimate warming are 'unfounded', study shows

This may or may not have been hasty.

I see that there is some information on climateaudit that the statistical methods used are flawed. I do not have the background to double check that. I hope the authors can check it out and act appropriately.... quickly.

Moderator Response:

[JH] Your comment appears to be a thinly-disguised attempt to castr a shadow on the information presented in the OP. If so, please cease and desist playing such a game on this website.

Upon further review, this comment is retracted.

shoyemore at 18:15 PM on 6 February 2015

Katharine Hayhoe's climate elevator pitch

There are said to be three ways to persuade people rhetorically:

Logos (or Logic)
Ethos (or Authority)
Pathos (or Emotion)

The least effective is Ethos, the most effective is Pathos. However, it is a bit short-term. We can be swayed by a powerful, plausible sales pitch (e.g. Monckton!), and change our minds on reflection.

So Logos, which science uses, is the most effective in the long term for those willing to engage with it. Since Logos is demanding and tiring, it is difficult.

But for an "elevator pitch", Logos is pretty much long, slow thinking, so for a quick impression, go for Pathos every time.

Tom Curtis at 15:30 PM on 6 February 2015

Kevin Cowtan Debunks Christopher Booker's Temperature Conspiracy Theory

daveburton @20, first and most importantly, your comments about the phrase "dishonest adjustments" are entirely beside the point. You completely fail to adress the substantive points I made in my comment @17, failing in particular to adress the clear evidence that there is substantial year to year variability in adjusted data, particularly in the early twentieth century. You further fail to adress the fact that the adjustments to land data, and to SST data in the early twentieth century have opposite effects on the trend. Your failure to adress these and other issues makes your comments about the phrase "dishonest adjustments" look like a simple, and deliberate distraction from the fact that your points have been refuted in detail, and that (apparently), you have no substantive response.

Second, you claim to "have said nothing about 'dishonest adjustments'". Never-the-less you are commenting on a critique of Booker's article, and Booker definitely suggests the adjustments are dishonest, calling them "scary chicanery". You, yourself summarize Booker's article by saying:

"Christopher Booker thinks NOAA is distorting global land temperature data to inflate reported global warming, and fan the flames of climate alarmism."

That is, according to you Booker is saying the adjustments were made with the intent to "... inflate the reported global warming, and fan the flames of climate alarmism", ie, that it was done from dishonest motives. As I did not indicate that it was your theory, my language was entirely justified and your attempted distraction is itself ungrounded.

Tom Dayton at 14:12 PM on 6 February 2015

Kevin Cowtan Debunks Christopher Booker's Temperature Conspiracy Theory

Dave Burton, you have revealed NOAA to be profoundly incompetent indeed, because their sinister attempt to hide the explanation of homogenization was so poor that a quick internet search revealed it in several place such as the CDIAC site. Congratulations.

daveburton at 13:25 PM on 6 February 2015

Kevin Cowtan Debunks Christopher Booker's Temperature Conspiracy Theory

Tom Curtis, just to be perfectly clear, I said nothing about "dishonest adjustments."

It is very possible to to make incorrect adjustments without conscious dishonesty, though simple error, or unrecognized bias. There's a very human tendancy for scientists to scrutinize data more critically if it is contrary to their preconceptions, than if it confirms them. That tendency can easily introduce bias in the reported results, despite everyone involved having the very best of intentions.

NOAA used to have, on their web site, a description of how they adjusted measured temperature data based on what seemed to me like a very crude proxy for urban heat island effect: satellite observations of nighttime illumination. That material is gone from their site, now, and they've blocked archive.org from archiving such materials, and I didn't save a copy (at least I don't think so), so I don't have the details. But the procedure seemed highly dubious, to me, when I read about it a few years ago.

That doesn't mean that those adjustments were dishonest, however.

My point wasn't about motives. I was simply addressing the misconception that NOAA's adjustments made a negligible difference in the reported result. They don't. They make a big difference.

Stephen Leahy at 13:00 PM on 6 February 2015

Water is far more valuable and useful than oil

denisaf: There is misunderstanding about water as renewable. Water does recycle but does it return to where it's needed and in an acceptable time frame? Not always. Drain a lake and it may not refill in your lifetime — where will you get your water in the meantime? The Aral Sea disaster offers an example.

Water scarcity is about time and place.

Treesong2: Only a small fraction of the water in Lake Erie is renewable - the rest is the gift of the last ice age. Lake levels have been falling in recent years mainly due to warmer winters. While your toilet water may be recycled, some of it is lost through leaks and contamination (sewage sludge).

Toilet use is a very small part of our daily water use which is the point of the article.

OPOF: The article doesn't get into the impacts of climate change - the book does.

CBDunkerson: Desal is likely to be out of reach for most people suffering from water scarcity. 1.2 billion people today do not have access to clean water. Half the world cannot turn a tap in their home to get drinking water. Let's hope there are break throughs in desal energy/cost requirements.

JH: Good links. 90% of water use is to grow food. Climate change is going to make feeding ourselves much harder.

daveburton at 12:57 PM on 6 February 2015

Kevin Cowtan Debunks Christopher Booker's Temperature Conspiracy Theory

Tom Dayton, (re #15) the 900% example was intended as an illustration of the problem with using a cherry-picked subset of the full time series. It is an example of what not to do. But it is computed accurately. Seriously. It really is >900%.

However, (re #16) I did not say that the temperature anomalies do not exhibit much short-term variability. I said that NOAA's adjustments do not exhibit much short term variability. Which is right.

I concede, however, that when the adjustments are compared to the unadjusted temperature trend, e.g. by computing the adjustment amount as a percentage of the trend, the result is senstitive to both numbers. However, I did not pick an anomolously low right-hand endpoint to minimize the early 20th century warming. 1970 actually represented a minor peak in temperature: it was warmer than 1967, 1968, 1969, 1971 & 1972.

Tom Curtis at 12:53 PM on 6 February 2015

Kevin Cowtan Debunks Christopher Booker's Temperature Conspiracy Theory

Tom Dayton @16, daveburton was incorrect (see my point 2 @17 above), but neither he nor I were talking about the simple anomaly on that point. Rather, we are talking about the adjustments, the difference between raw and homogenized data, which also shows substantial short term variability. Just not as much as the actual anomaly, and much less over the last 50 years.

Tom Curtis at 12:51 PM on 6 February 2015

Kevin Cowtan Debunks Christopher Booker's Temperature Conspiracy Theory

daveburton @14:

"You are correct, Tom, but his graph was for the last 114 years, and his conclusion ("why would they [bother to] do that") only makes sense if the sum of NOAA's adjustments were inconsequential. It doesn't make sense if NOAA's adjustments were only inconsequential for one cherry-picked time interval, and very consequential for the whole record."

I indicated a couple of very substantial reasons as to why we should concentrate on the period since 1950. Because there are substantive reasons for the choice of time period, it is not a cherry pick. Suggesting that it is without adressing those reasons amounts to simple name calling as an argument. However, leave that aside.

The simple fact of the matter is that the majority of early twentieth century warming is natural in origin. Anthropogenic factors account for approximately a third of that warming, or according to one recent analysis, effectively none of it. This can be seen by the relative slopes of temperature and CO2 concentration in the early, and late twentieth century:

More substantively, comparing model retrodictions with global temperatures shows the models substantially underpredict the global trend in the early twentieth century:

(Note, the pink shaded area is the model prediction for anthropogenic plus natural forcings.)

That discrepancy can be accounted for almost completely by reference to short term variability not included in model forcings, primarilly ENSO, although the unusual warmth in the 1940s is still not accounted for.

So, with this knowledge in hand, your argument then becomes that the people at NOAA increased temperature trends in the early twentieth century when such increases run contrary to the AGW narative, but did not significantly increase trends in the late twentieth century where such increases would have supported the narrative.

Expanding the analysis beyond the late twentieth century does not make the theory of dishonest adjustments any more plausible. It just means you need to understand more background information to understand the relevance of what is happening.

"You're right about the temperatures, Tom, but that's not what's being compared (by Dr. Cowtan, and by me). What's being compared is the temperature adjustments (i.e., the difference between adjusted and unadjusted temperatures), and they do not exhibit much short-term variability."

Here are the difference between raw and final USHCN temperatures:

Very clearly, you are wrong to claim "...they do not exhibit much short-term variability". There is substantial short term variablity, particularly in the early twentieth century, and particularly for 1900 itself. That is, of course, for the contiguous United States. Unfortunately I do not know of a similar chart for the global land record, but there is no reason to think it would also lack variability from year to year in adjustments. So while the adjustments show less short term variability than do the actual temperatures, never-the-less, they show substantial short term variability and comparisons of differences should be made using trend values.

"SST is not air temperature, and, unfortunately, the SST data quality through most of the 20th century is even sketchier and subject to more adjustments than the land air temperatures."

First, it would be nice if there was a more or less continuous, global record of air surface temperatures at 2 meters above sea level. Unfortunately no such record exists, so you make use of the records you in fact have rather than pretend to complete ignorance. Those records are, however, strongly relevant. As anybody knows, who has lived both inland and near the sea, the thermal mass of the surface waters mean they absolutely dominate the variability in nearby air masses. That is so even 50 km inland, let alone a mere 2 meters above the surface of the water. Although there will be some difference in the actual values between SST and 2 meter air temperature immediately above the surface, they will not be large and they will be consistent so that trends in the former would have been reflected in trends in the later.

Given this, I regard your exclusion of SST from the record of interest as a mere cop out. It is particularly the case given that all Global Mean Surface Temperature records use SST data over oceans, for want of any better record to use.

Second, the SST temperature data is in fact very extensive, although it does show some coverage lapses (as does the land record), particularly in the Southern Ocean.

Third, while the SST data is also subject to adjustments, they are not subject to "the same adjustments":

(Source)

As you can see, while the net effect of adjustments on land has been to cool the early twentieth century relative to the late twentieth century, the net effect on SST has been the opposite. That is, it warms the early twentieth century relative to the late twentieth century. That is, it reduces the twentieth century temperature trend.

So, if we look at the actual data, it does not support your dismissal, which is shown to be glib, and misleading. Contrary to the impression you convey, combining land and SST data will reduce the global trend from 1900 more than would be the case by simply diluting the 30% land coverage with data with no trend adjustment.

"You can't do that, Tom. It's mathematically incorrect. The percentage difference isn't a sum that you can divide by 11.5 to get the per-decade adjustment-generated percentage difference in warming, it's an average."

Then it is a good thing that that is not what I did. Rather, I projected the difference in adjustment over the last 50 years back over the record to 1900. That, of course, only gives a ball park figure, and given the additional data noted at point three above, underestimates the reduction in the difference for global figures. It is near enough, however, for this discussion.

Tom Dayton at 11:05 AM on 6 February 2015

Kevin Cowtan Debunks Christopher Booker's Temperature Conspiracy Theory

Dave Burton, you are incorrect that the temperature anomalies do not exhibit much short-term variability. For example, see the escalator graph.

Tom Dayton at 10:18 AM on 6 February 2015

Kevin Cowtan Debunks Christopher Booker's Temperature Conspiracy Theory

No, Dave Burton, it is not okay to compute trends by merely connecting end points. You need to compute a regression line. Seriously, a 900% change?!

daveburton at 09:50 AM on 6 February 2015

Kevin Cowtan Debunks Christopher Booker's Temperature Conspiracy Theory

michael sweet wrote, You have mislabeled your graph. In the video the graph is clearly labeled NOAA Paraguay data. You have changed the label to Globally averaged Land Surface data."

No, Michael, that graph is global. Listen to Dr. Cowtan describe it, at 3:30:
https://www.youtube.com/watch?v=qRFz8merXEA#t=210
He says, "We can calculate a global land temperature record using..."

Tom Curtis wrote, "in the video Kevin Cowtan says (3:55) that "... the NOAA adjustments make only about a 3% difference to the amount of warming over the last 50 years" (my emphasis)."

You are correct, Tom, but his graph was for the last 114 years, and his conclusion ("why would they [bother to] do that") only makes sense if the sum of NOAA's adjustments were inconsequential. It doesn't make sense if NOAA's adjustments were only inconsequential for one cherry-picked time interval, and very consequential for the whole record.

For instance, if you compare the adjusted to unadjusted warming for the first 70 years of the graph (1900 to 1970), instead of the last 50 years, you'll find that the adjustments increased the net warming by more than 900% (from 0.025 °C to 0.257 °C).

Of course, you're probably saying to yourself, "but that's cherry-picking!" — and you're right. But no more so than just examining the last 50 years is cherry-picking.

Tom continued, "you have made your determination simply by comparing end points. Because of the high short term variability of temperatures, such comparisons can easilly mislead by showing atypical values."

You're right about the temperatures, Tom, but that's not what's being compared (by Dr. Cowtan, and by me). What's being compared is the temperature adjustments (i.e., the difference between adjusted and unadjusted temperatures), and they do not exhibit much short-term variability.

Tom continued, "it is the land only data, of which Kevin Cowtan indicates their is a 10% difference after adjustments."

But that's only for the cherry-picked last 50 years.

Tom continued, "That 10% is reduced to 3% by the inclusion of SST data."

SST is not air temperature, and, unfortunately, the SST data quality through most of the 20th century is even sketchier and subject to more adjustments than the land air temperatures.

Tom continued, [if you multiply by 30% because only 30% of the globe is land] "your 35% would reduce to approximatly 11% difference over a 115 year interval, or less than 1% difference per decade."

You can't do that, Tom. It's mathematically incorrect. The percentage difference isn't a sum that you can divide by 11.5 to get the per-decade adjustment-generated percentage difference in warming, it's an average.

John Cook at 08:39 AM on 6 February 2015

Scott Mandia on teaching students to debunk climate misinformation

Thanks for your comment - I'll be in touch, would be interesting to hear more about your course and you may be interested in our upcoming MOOC, Making Sense of Climate Science Denial, which will include a great deal of creative commons material available for educators and communicators.

Tom Dayton at 08:09 AM on 6 February 2015

Kevin Cowtan Debunks Christopher Booker's Temperature Conspiracy Theory

Zeke Hausfather has an excellent post on adjustments to temperature, though at an unfortunate site.

Runrig at 06:26 AM on 6 February 2015

Lessons from Past Climate Predictions: IPCC FAR

Folks,

Further to posting my/your input over at Phys.org, Mr bell posted up this (whilst not acceding defeat).

"Thank you Tony for your honest analysis and discussing the content of my claims. I'll pursue this at the discussion thread you provided.

It's too bad there aren't more people on this thread with intellectual honesty, but I do appreciate yours."

So you may well be able to take him in in person.

PS: he has been generally polite (and always with me), except when when goaded.

Tony

Maggnum at 06:14 AM on 6 February 2015

Lessons from Past Climate Predictions: IPCC FAR

I just want to comment on the well thought out answers on this thread, with thanks. I should have thought to have brought the problem here, and thanks Tony for doing so.

Mr. Bell is somewhat less objective than he holds himeslf out to be. Tom. your review seems to hit the crux of the issues - Mr. Bell is using a deceptive and incomplete "analysis" as a means to call the IPCC as a whole deceptive or incompetant. I think that, in and of iteself, is enough to put his "analysis" into its proper perspective.

Thank you Tom for looking into it, and thank you Tony for bringing it here for review.

Tom Curtis at 04:23 AM on 6 February 2015

Kevin Cowtan Debunks Christopher Booker's Temperature Conspiracy Theory

daveburton @9 and @10, in the video Kevin Cowtan says (3:55) that "... the NOAA adjustments make only about a 3% difference to the amount of warming over the last 50 years" (my emphasis). By comparing the range from 1900-2014, you are not checking his claims, but an entirely different claim that he did not make. You may think this is a minor point, but in fact the key attribution statement for the IPCC is with regard to the period 1950-2010. That is, it is with regard to (approximately) the last half century. There are several reasons for that, one of which is the relative accuracy of the temperature record post 1950. Consequently there are substantive reasons why the IPCC and Kevin Cowtan concentrate on the most recent 50-60 years.

Further, on checking your spreadsheet it becomes very apparent that you have made your determination simply by comparing end points. Because of the high short term variability of temperatures, such comparisons can easilly mislead by showing atypical values. To avoid this, the correct method is to determine the respective trends, and compare them directly, or if you insist on comparing end points, compare the endpoints of the trendlines. This is particularly the case as it is future temperature trends we are concerned with. Comparing the endpoints for 1950-2014 (14% difference by your method), 1965-2014 (10% difference by your method) shows the effect of increasing accuracy overtime resulting in less difference between adjusted and unadjusted data, and highlights the problem with using endpoints.

Finally, although Michael Sweet is incorrect to describe the graph as Paraguay data, it is the land only data, of which Kevin Cowtan indicates their is a 10% difference after adjustments. That 10% is reduced to 3% by the inclusion of SST data, and we could expect a similar scale of reduction in your figure if it compared land/ocean temperature data rather than land only data. That is, your 35% would reduce to approximatly 11% difference over a 115 year interval, or less than 1% difference per decade.

michael sweet at 03:42 AM on 6 February 2015

Kevin Cowtan Debunks Christopher Booker's Temperature Conspiracy Theory

DaveBurton,

You have mislabeled your graph. In the video the graph is clearly labeled NOAA Paraguay data. You have changed the label to Globally averaged Land Surface data. Dr. Cowtan points out that such a change in the Paraguay data would only affect Global data by 3%.

How could you make such a large error by mistake? It appears that you are deliberately trying to mislead whoever you show your mislabeled graph. This must be a conspiricy to defraud the public about this data. Who is paying you to make these fradulent claims?

It is well known that change of time of reading and change in temperature monitoring stations can make readings this different. The installation of Stephenson screens as described in 5 above woud cause this change.

It is easy to claim dramatic changes have been made when you mislabel the data.

daveburton at 03:37 AM on 6 February 2015

Kevin Cowtan Debunks Christopher Booker's Temperature Conspiracy Theory

I didn't say that very well.

"...had increased globally averaged land surface temperatures by 35%"
should have been:
"...had increased the warming seen in globally averaged land surface temperatures by 35%"

daveburton at 02:53 AM on 6 February 2015

Kevin Cowtan Debunks Christopher Booker's Temperature Conspiracy Theory

Dr. Cowtan's final argument was that the adjustments were too tiny to be suspicious. “Why would they do that?” he asks at the end of his video, meaning why would anyone commit fraud for an inconsequential difference in the result?

However, I digitized the endpoints in the last graph which he showed in his video, and found that NOAA's adjustments had increased globally averaged land surface temperatures by 35%.

35% is not inconsequential.

The graph w/ comments, and a small spreadsheet with the numbers, are here:
http://tinyurl.com/cowtan-v-booker

Here's a half-size version of the annotated graph:

Moderator Response:

[RH] Adjusted image size.

howardlee at 02:34 AM on 6 February 2015

Claims that climate models overestimate warming are 'unfounded', study shows

In the long view, paleoclimate work presented in the AGU14 for the Miocene suggests sensitivities at the upper end of the IPCC range. In other words, the bahavior of Earth's climate in the past does not support the idea that model-based projections are overstated. If anything they suggest the opposite. There should hopefully be a post on this coming out in a few days.

swampfoxh at 01:57 AM on 6 February 2015

Scott Mandia on teaching students to debunk climate misinformation

I have been teaching a course, "Global Warming: Proof or Politics?", designed for the general public using, for classroom space, public library meeting rooms in two counties in Virginia. I would like to correspond with skepticalscience.com people who are trying to get proper climate change information out to the public. My email is swampfoxh@hotmail.com

KR at 01:35 AM on 6 February 2015

Lessons from Past Climate Predictions: IPCC FAR

I'll bow to Tom Curtis's far better researched answer on this one. :)

Runrig at 21:57 PM on 5 February 2015

Lessons from Past Climate Predictions: IPCC FAR

Tom,

thanks again - I've put the latest response from you here ...

http://phys.org/news/2015-01-climate-dont-over-predict.html

And have suggested Mr Bell call in here for more "learned" discussion.

Oh, and if you'd care to call in on Phys.org to make comments you'd be more than welcome!

Tony

Bart at 20:30 PM on 5 February 2015

Climate researcher Bart Strengers wins wager with climate sceptic Hans Labohm

Thanks a lot for all your comments!

Below I tried to answer most of them:

@ranyl: I surely have considered that the CS might be higher. I just explained why the lower bound of the IPCC-range has been lowered from 2.0 to 1.5 in AR5.

Studies of my institute (Netherlands Environmental Assessment Agency, PBL) show that a >50% change to keep the warning limited to 2 degrees, implicates a major emission reduction effort with negative emissions by the end of this century.

If you want a bigger than 95% change, this reduction effort will be even higher. We did not study the implications of even lower temperature limits, but I think you are right this might result in a current negative carbon budget.

@Wili: I did not write we have 0.1 degrees warming in 5 years, but that the average temperature in the period 2010-2014 was 0.1 degrees higher than the average of the 10 years before that. TonyW explains how this results in 0.15. (UAH has a linear trend of 0.14 starting in 1979 by the way). Furthermore, you are right that volcanoes can result in a ‘cold’ year and thus can have a large influence on the average of an extremely short period of just 5 years. This is precisely one of the reasons why I said in 2009 that I could lose the wager.

@jja: Interesting publication. In the Dutch media I wrote that I think that the change the next 5 years will be warmer again than the 10 before is at least as big as 5 years ago. Aerosol emission reductions in China - as far as it is really true, given the discussion in this tread - might be another reason why this will probably be the case.

@Paul W and Philippe: You are right there is a problem there. What I meant in 2009 is that the integral of the pdf on the left of the ‘best estimate’ of 3.0 is smaller than the integral on the right. In other words P(ECS<3.0) < P(ECS>3.0). P(ECS<3.0) is the chance that the real world ECS is lower than the best estimate and thus that the best estimate is an overestimation. And according to the same reasoning P(ECS>3.0) means that the best estimate is an underestimation. However, there are two problems here. The first is that I am not so sure anymore that the proposition P(ECS<3.0) < P(ECS>3.0) was actually true in 2009. I would love to hear your opinion on that. The second problem is that in AR5 there is no best estimate anymore, so it is actually impossible to say whether my proposition still holds. Because it was too complicated to explain this to a broader audience, I tried to make the point I did. I might have done that differently now, though.

chriskoz at 10:11 AM on 5 February 2015

2015 SkS Weekly News Roundup #6A

The article about battery storage & demise of fossil fuels is very interesting. Especially the actual link to the Citigroup report therein that I repeat here:

solar-battery-storage-socket-parity

Important part of this analysis is the fact, as the article notes:

Figure [therein] illustrates Citigroup’s point. It assumes a large portion of the solar output is self-consumed rather than sold to the grid, so the ‘income’ is primarily avoided electricity bills rather than energy sales.

That's exactly what;s happening in Australia: demand for electricity drops as rooftop panel penetration grows. However, I'm not sure how they incorporated that change in consumption model in their prediction of parity. To learn more, it's worthwhile to visit (or at least watch the outcome of:
2015 Australian Energy Storage Conference in Sydney

Tom Curtis at 09:09 AM on 5 February 2015

Lessons from Past Climate Predictions: IPCC FAR

Runrig @18, I get slightly different values, particularly for the upper range as note in my prior comment. However, given that I must judge the year by eye, and given that the reproduction of the graph shows it was a photocopy of a page, not perfectly flat on the plate, I would not argue the toss. Two points, however. First, Bell bases his analysis on the range of BaU through to scenario D on just one climate sensitivity value, rather than just BaU across the range of climate sensitivity values. Second, you mention "the full range of of scenarios". I think it is better to be more precise and mention the range of scenarios and climate sensitivities.

Runrig at 05:46 AM on 5 February 2015

Lessons from Past Climate Predictions: IPCC FAR

Tom,

Thanks for the heads up on the full range of scenarios shown by AR5 ... I think the answer is therefore a simple one.

Bell is basing his analysis on the basis of just the BaU scenario ... so examining the 2 extremes of the graphs (fig 6.11), I get a range of 0.5-1.9C above '90 (+/- 0.1C) ... which is what is shown in the AR% graph!

Tony

Tom Curtis at 03:49 AM on 5 February 2015

How we discovered the 97% scientific consensus on man-made global warming

Stranger 26, Mike Hulme gives every appearance of having become a post modernist. Do not expect too much in the way of rational behaviour from him.

Tom Curtis at 03:46 AM on 5 February 2015

Lessons from Past Climate Predictions: IPCC FAR

Runrig, I disagree with KR's assessment. The reason is that if you look at the IPCC FAR Chapt 6, fig 6.11, you will find it shows three panels. Panel (a) shows the high (4.5 C per doubling) climate sensitivity estimate; panel (b) shows the moderate (2.5 C per doubling) climate sensitivity estimate; and panel (c) shows the low (1.5 C per doubling) climate sensitivity estimate:

Comparing differences between 1990 and 2035, as best as I am able, the top of the range is BaU in panel (a), with an approximatley 3 C increase. In contrast, the bottom of the range (scenario D in panel (c)) shows less than 0.5 C increase. That, then, is the full range.

Now, if the climate sensitivities had been reduced inline with KR's arguments, both the top and the bottom of the range would be reduced. Instead, however, we find the top of the range shown in AR5 is 1.85C above the 1990 level, whereas the bottom of the range is 0.58 C above. Both the top of the range and the bottom of the range have been contracted towards the median value, and by about the same proportion. As a result, the bottom of the range shows a higher, not a lower value as required by KR's line of reasoning.

Even if we restrict the analysis to the median value range shown in Fig 9 of the Summary for Policy Makers, the range shown in FAR is approximately 0.6 to 1.5 C. If that is what is shown, the lower range is unadjusted (contrary to KR's explanation), and the upper range is increased.

If I were to hazard a guess as to what the IPCC has done, it would be that they have used historical values for forcings from 1990-2010, and the scenarios thereafter. If that is what they have done, it would contract both the high and low estimates towards each other as there will be less disparity in the forcing history. That, however, is only a guess, and you would have to consult with one of the IPCC authors to get a definitive answer.

Finally, I will note that if Doug Bell is going to complain about the "IPCC deception", it would behove him to show all three panels of the IPCC FAR predictions, not just the middle range values that he actually shows. That strikes me as rather more deceptive than anything the IPCC may have done. The excuse that he uses the values shown in the summary for policy makers (should he make it) is irrelevant in that the caption of the AR5 article explicitly refers to Fig 6.11 as the source of the projections shown.

Further, even using Fig 9 from the summary for policy makers, he exagerates the warming shown substantially. As noted, the difference between 1990 and 2035 for BaU in that chart is about 1.5 C. He, however, shows it as greater than 2 C.

Stranger8170 at 03:44 AM on 5 February 2015

How we discovered the 97% scientific consensus on man-made global warming

Thanks Rob.

I know that the deniers using newspaper blogs will never be convinced. I know there are people who read the blogs who might not have strong opinions. We have a university bio chemist and a philosopher of science taking part in some of our discussions. I think that people who read the blog but have no strong opinion would find the AGW side on our blog much more credible just by the way they conduct their arguments. I think that might a benefit but I have to say I've no way of knowing. I'm probably wasing time.

I have have asked, even on this website why deniers wouldn't fund their own survery since it would only cost the Koch brothers of some other organization chump change to do it. I figured they were afraid of the Richard Muller effect.

I want to avoid being repetitious but I'm still bothered by the Mike Hulme thing. As a layman I just don't know what to think about his comments concerning the survey. It may be something I should let go of but I'd like to get in inkling of where he's coming from because if he’s so concerned about the huge amounts of carbon going into the atmosphere he sure doesn’t seem to be helping the cause. Just the opposite.

Esop at 03:12 AM on 5 February 2015

Cowtan and Way 2014: Hottest or not?

In reference to JCHs question above: November also saw a drop in average temps (and the media over here (Norway) was all over it, as it meant a reduction in the chances of 2014 breaking the record). If I remember correctly, there was a major Arctic blast into North America, due to a major north Pacific cyclone pushing warm air into the Arctic and pushing cold air into NA.

It seems that we get a drop in the average global temp each time the cold Arctic air flows down into lower latitudes where we can properly measure temps, but we are unable to properly account for the heat that flows into the Arctic at the same time, causing a sizeable cool bias in the global average.

If I remember correctly, most of the much hyped ''pause'' was caused by colder winter NH temps, while summer NH temp as well as summer and winter SH temps have risen steadily, without much trace of a pause. It would not surprise me if most of the ''pause'' was caused by not yet perfect methods for measuring the results of the shuffling of NH air masses during the NH winter. C&W and HadCrut 4 was a big step in the right direction, but I have a strong feeling that there is still a rather big cool bias, as indicated by the November temps.

Runrig at 03:04 AM on 5 February 2015

Lessons from Past Climate Predictions: IPCC FAR

Thanks again KR - If you dont mind I'll post up your response here on the Phys.org thread.

Tony

Rob Honeycutt at 02:59 AM on 5 February 2015

How we discovered the 97% scientific consensus on man-made global warming

Stranger... What most people miss about the Cook paper is that the main point is not the actual "97%" number. It's about the difference between the public's incorrect perception of the level of consensus and the actual level of consensus.

What "skeptics" always fail to do, whilst they twist and writhe over the data, is attempt to apply their own methods for evaluating the level of consensus. Or, perhaps they have and found out that something close to 97% is actually correct... and they don't want to report that.

The importance of the research is, showing the difference between perception and reality on the part of the public relative to the level of acceptance of AGW tends to move people toward acceptance of the science.

The people at your newspaper blog ranting about the research are going to do that no matter what. That's fine. Those people will never be moved and they needn't be moved. In fact, I would hold that it's better they aren't because they become a foil against which to communicate the stark reality of AGW.

When I encounter these people I usually say one of two things:

1) Okay, you don't like the research. Do your own. Show us what you believe the level of consensus is, but you need to do what Cook et al did and go through the tough process of getting your results peer reviewed. (And FYI, that ain't easy.)

2) Since Cook et al took the self-skeptical approach of getting researchers to rate their own papers, the results are likely to be very robust. And that's not to even mention the other research papers that show similar results.

So, we now have numerous peer reviewed papers showing a very high level of scientific consensus on AGW. We have no papers showing otherwise.

"Skeptics" are batting a big fat zero right now on this topic.

KR at 02:57 AM on 5 February 2015

Lessons from Past Climate Predictions: IPCC FAR

Runrig - I haven't dug into the history of _that particular figure_. However, the IPCC reports are of the current state of the art; the Myhre et al results were incorporated as far back as the 2001 SAR, and by now are likely just considered part of background literature/knowledge.

It's also noteworthy that the FAR projections were based on emission scenarios higher than actually occurred - I suspect some of the adjustment may come from using observed forcings to rescale FAR projections over intervening years.

Regardless, the fact that Bell hasn't come across the initial reference(s) to projection rescaling (based on forcing updates and historic emissions) shouldn't be interpreted as nefarious actions by the Illuminati, as he has apparently concluded. Rather, it means he isn't wholly familar with the literature.

miffedmax at 02:56 AM on 5 February 2015

2015 SkS Weekly News Roundup #5B

And as reliably a ever, the Wall Street Journal shows up the other day with another "models aren't accurate" trope on its editorial page, using the same tired old short-term time frames. It is the very definition of tragicomedy.

Runrig at 02:36 AM on 5 February 2015

Republicans have one option to eliminate EPA carbon regulations

KR,

Yes he is indeed, as has been rammed home to him by "Maggnus", but on the other hand has been polite and accepted some criticism and apologised on occasion.

I have replied also on the appropriate thread.

Thanks

Tony Banton

Runrig at 02:32 AM on 5 February 2015

Lessons from Past Climate Predictions: IPCC FAR

KR,

Thankyou for that.

It's what I thought - and what i told him.

He still thinks that it is "deceptive" that the IPCC in that AR5 graph has the new ECS, without reference to it's being changed.

Is that right?

There is no mention that I can see. I was hoping to pass on that statement from the IPCC to him

Tony

John Hartz at 01:44 AM on 5 February 2015

Water is far more valuable and useful than oil

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