The usual suspects in the blogs and media have been bloviating about the record warmth of March and spinning it to redline for maximum fear factor, with the “loaded climate dice” theme. For example we have Andrew Freedman of Climate Central and his post, Global Warming May Have Fueled March Heat Wave Odds.
Scary big red maps aside, a quiet look at the data tells an entirely different story.
At least NCDC had the good sense in their report to avoid linking a weather pattern to AGW:
A persistent weather pattern during the month led to 25 states east of the Rockies having their warmest March on record. An additional 15 states had monthly temperatures ranking among their ten warmest. That same pattern brought cooler-than-average conditions to the West Coast states of Washington, Oregon, and California.
Dr. Martin Hoerling on NOAA says much the same thing, attributing much to “randomness” and citing a similar event in March 1910 as seen below in the NCDC data plot:
It is difficult to make credible claims that March 2012 was AGW driven when looking at March 1910 when global CO2 was well below Dr. James Hansen’s posited “safe” 350 PPM level.
Hoerling also says that pulling an AGW signal out of this has “…statistical challenges in estimating how such a shift in distributions would alter extreme event odds, especially of the intensity observed in March 2012 whose magnitude was likely on the order of 4 – 6 standard deviations.”
Dr. Roy Spencer writes that the southerly wind component was the cause, and even shoots down the “yes but” before it gets out of the gate.
New Evidence Our Record Warm March was Not from Global Warming
by Dr. Roy Spencer
As part of my exploration of different surface temperature datasets, I’m examining the relationship between average U.S. temperatures and other weather variables in NOAA’s Integrated Surface Hourly (ISH) dataset. (I think I might have mistakenly called it “International” before, instead of “Integrated” Surface Hourly).
Anyway , one of the things that popped out of my analysis is related to our record warm March this year (2012). Connecting such an event to “global warming” would require either lazy thinking, jumping to conclusions, or evidence that the warmth was not caused by persistent southerly flow over an unusually large area for that time of year.
The U.S. is a pretty small place (about 2% of the Earth), and so a single high or low pressure area can cover most of the country. For example, if unusually persistent southerly flow sets up all month over most of the country, there will be unusual warmth. In that case we are talking about “weather”, not “climate change”.
Why do I say that? Because one of the basic concepts you learn in meteorology is “mass continuity”. If there is persistent and widespread southerly flow over the U.S., there must be (by mass continuity) the same amount of northerly flow elsewhere at the same latitude.
That means that our unusual warmth is matched by unusual coolness someplace else.
Well, guess what? It turns out that our record warm March was ALSO a record for southerly flow, averaged over the U.S. This is shown in the next plot, which comes from about 250 weather stations distributed across the Lower 48 (click for large version; heavy line is trailing 12 month average):
Weather records are broken on occasion, even without global warming. And here we see evidence that our March warmth was simply a chance fluctuation in weather patterns.
If you claim, “Well, maybe global warming caused the extra southerly flow!”, you then are also claiming (through mass continuity) that global warming ALSO caused extra northerly flow (with below normal temperatures) somewhere else.
And no matter what anyone has told you, global warming cannot cause colder than normal weather. It’s not in the physics. The fact that warming has been greatest in the Arctic means that the equator-to-pole temperature contrast has been reduced, which would mean less storminess and less North-South exchange of air masses — not more.
renewable guy says:
April 18, 2012 at 11:51 am
Both temperature records show an acceleration of warming in the last 30 years.
See the graphs below. They show essentially identical 30 year slopes many years apart.
http://www.woodfortrees.org/plot/hadcrut3gl/from:1900/plot/hadcrut3gl/from:1912.33/to:1942.33/trend/plot/hadcrut3gl/from:1982.08/to:2012.08/trend
renewable guy:
You support your assertion that global warming is “accelerating” by stating at April 18, 2012 at 11:51 am;
“hadcrit 3 which is biased cool due to poor global coverage shows warming
1840 to aprox 2010
Trend: 0.44 ±0.07 °C/century (2σ)
There is now a Hadcrut 4 which takes into better account areas of the earth not covered previously in the norther hemisphere
Trend: 0.45 ±0.06 °C/century (2σ)”
Sarc on/ Clearly, as you assert and according to the data you provide, global warming is accelerating; i.e.
If one ignores the error ranges then global warming increased from 0.44 °C/century to 0.45 °C/century in the months between final publication of HadCRUT3 and first publication of HadCRUT4. /Sarc off
However, both data sets show there has been no global warming for the last 15 years.
So, please explain how “acceleration” equates to a trend reducing from to 0.44 °C/century since 1840 to zero°C/century since 1997.
And an assertion that 15 years is “too short” will not wash. You are claiming “acceleration” so you need to provide evidence to justify it. The data sets you cite deny “acceleration”. Indeed, they imply (but do not show because of lack of statistical significance) that global warming is decelerating.
Richard
Friends:
I wish to point out that there is a deliberate error in my above post addressed to ‘renewable guy’.
The error is that I used an end-point-fallacy.
The data is cyclic with 30-year alternate periods of warming and cooling added to the long-term warming trend from the LIA. Hence, the stasis of the last 15 years is probably similar to the stasis of the 30-year period from ~1940 to ~1970.
As Werner Brozek points out (with a link) at April 18, 2012 at 1:59 pm, there is no evidence of any change in the trends when this periodicity is acknowledged. Hence, any claim of “acceleration” or “deceleration” since 1840 is spurious. The trend has decelerated over the last 30 years but this is fully accounted by the periodicity.
The reason for my deliberate error is that AR4 used exactly the same end-point-fallacy to ‘prove’ the asserted acceleration: I have used that same trick to show the opposite using more recent data.
Richard
“Both show declines in global temperature. If there was accelerated warming, the charts would be rising, not falling. ”
The point is that 2 years of cooling is WAY to short of a time frame for drawing the “cooling conclusion” you seem so intent on making.
The 150 yr data shows an upward slope, with an acceleration
The 20 year data would (I suspect) show a larger upward slope, but with a deceleration.
The 2 year data shows a downward slope, with probably no significant acceleration or deceleration.
So the interpretation depends on the time frame you look at. Perhaps the recent year-time-scale downward slope and the decade-time-scale downward acceleration will translate to a century-time-scale downward slope and downward acceleration, but we are certainly not there yet.
I don’t have time to look at all your other charts. My impression from a quick glance (and other glances at other times) is that many of them are interesting and valid, but that many of them cherry-pick or don’t really say what you think they do. For a quick example, you say global temperatures have remained on the same trendline, but then link to Central England temperatures (bad practice in wording). Furthermore, the graph is intentionally scaled to make the trend look small (bad practice in graphing) . Finally, the last few decade (and the first few for that matter) show a large deviation above the trendline, indicating that the trendline is NOT a good fit for the last few decades (bad practice in interpretation).
Richard S Courtney
1997 to 2012
Trend: 0.84 ±1.52 °C/century (2σ)
1995 to 2012
Trend: 1.36 ±1.30 °C/century (2σ)
Quite a difference between the two in just two short years. That’s what they mean
by the variance in the data. 1995 produces a great deal of difference. This is also why they talk about the 95% significance.
Richard
As Werner Brozek points out (with a link) at April 18, 2012 at 1:59 pm, there is no evidence of any change in the trends when this periodicity is acknowledged. Hence, any claim of “acceleration” or “deceleration” since 1840 is spurious. The trend has decelerated over the last 30 years but this is fully accounted by the periodicity.
#####################
1982 to 2012 30 years
Trend: 1.85 ±0.54 °C/century (2σ)
1952 to 1982
Trend: 0.11 ±0.58 °C/century (2σ)
1922 to 1952
Trend: 0.97 ±0.56 °C/century (2σ)
Here are the different 30 year trends back to 1922. Warming increase has varied like it has been doing in the last 30 years. There are some shorter cooling trends, but the overall average is warming.
Werner Brozak,
Interesting WFT graph, thanks. And this graph shows that the effect of CO2 is much smaller than claimed. [I have lots of similar graphs if renewable guy or anyone else is interested. They all show the same non-corellation with temperature.]
There has been steady, natural global warming since the LIA. But real evidence is lacking showing that CO2 is a major factor. The effect of CO2, if any, is too small to measure.
I forgot to label the last two posts. The data came from hadcrut 4
renewable guy says:
April 18, 2012 at 6:49 pm
I forgot to label the last two posts. The data came from hadcrut 4
Are you able to get the 2 sigma error bars as well from WFT? If so, I would be happy to know how. Thanks! By the way, Hadcrut4 only goes to December 2010 so a relatively cold 2011 is not included yet.
Richard S Courtney says:
April 18, 2012 at 2:15 pm
However, both data sets show there has been no global warming for the last 15 years.
Hadcrut3 certainly shows this with a slope of 0 for 15 years, especially if the February anomaly ever gets posted. As for Hadcrut4, I am assuming you mean with error bars and within 2 standard deviations. Is that correct? The way I see it, the slope for Hacrut4 WOULD be 0 for 11 years and 4 months IF it were up to date. (It stops in December 2010 now.) Here is how I arrived at that conclusion.
HADCRUT4 only goes to December 2010 so I had to be a bit creative. What I did was get the slope of HADCRUT3 from December 2000 to December 2010. Then I got the slope of HADCRUT3 from December 2000 to the present. The DIFFERENCE in slope was 0.00607 – 0.00165 = 0.00442 lower for the latter. The positive slope for HADCRUT4 was 0.00408. So IF HADCRUT4 were totally up to date, I conclude it would show no slope for at least 11 years and 4 months going back to December 2000. (It could be a month longer if the February anomaly for HADCRUT3 of 0.19 is ever officially published. On the basis of what GISS says about March, March would not change things either.) See:
http://www.woodfortrees.org/plot/hadcrut4gl/from:2000/to/plot/hadcrut4gl/from:2000.9/trend/plot/hadcrut3gl/from:2000/plot/hadcrut3gl/from:2000.9/to:2011/trend/plot/hadcrut3gl/from:2000.9/trend
Werner Brozek:
Thankyou for your post at April 18, 2012 at 9:56 pm. I agree all it says and I confirm you are right when you say to me;
“As for Hadcrut4, I am assuming you mean with error bars and within 2 standard deviations. Is that correct?”
Richard
renewable guy:
Your post at April 18, 2012 at 6:39 pm indicates that you failed to understand my posts at April 18, 2012 at 2:15 pm and April 18, 2012 at 2:33 pm.
Yes, there has been warming. It is the recent part of the warming from the LIA which has been happening for centuries. But there is no evidence – none zilch, nada – that there has been any change in the rate of that warming recently.
As I said;
“As Werner Brozek points out (with a link) at April 18, 2012 at 1:59 pm, there is no evidence of any change in the trends when this periodicity is acknowledged. Hence, any claim of “acceleration” or “deceleration” since 1840 is spurious. The trend has decelerated over the last 30 years but this is fully accounted by the periodicity.”
You seem to have been duped by a statistical trick used by the IPCC in AR4. As I said;
“The reason for my deliberate error is that AR4 used exactly the same end-point-fallacy to ‘prove’ the asserted acceleration: I have used that same trick to show the opposite using more recent data.”
I do not know how I could be more clear than by saying
1.
there is no evidence – none zilch, nada – that there has been any recent change in the rate of warming from the LIA
and,
2.
(as Smokey says) the absence of such change means the recent warming is fully explainable as being completely natural.
You may not like or want to accept those two facts, but they are indisputable facts. Of course, they do not rule out the possibility of an anthropogenic effect on the warming, but there is no evidence that such a putative anthropogenic effect is discernible.
Richard
Smokey, your graph looks a whole lot different with a more realistic “fit” drawn on it.
https://sites.google.com/site/sciencestatsandstuff/misleading-graphs
“I have lots of similar graphs if renewable guy or anyone else is interested. ”
Yes, I suspect you do have a lot more poorly done graphs (and I am also sure, some good ones, too). Maybe you can vet them a bit more before posting them.
Tim Folkerts,
The graphs copied in your link are not misleading. But the commentary is. Here is a graph from a completely different and very credible source, which shows the same non-relationship between CO2 and global temperatures.
Where is your god now? Why is he not saving you by causing accelerating temperatures? If your god existed, that’s what he would do.
richard,
WIth you nada zilch point of view, you are definitely in the right place for your validation for it.
Smokey says “Where is your god now? Why is he not saving you ”
Say what ???
I am quite content with my own personal views on god and religion, and whether or not I am saved has nothing to do with the infrared properties of gases. What do my religious views (or yours or anyone else’s) have to do with a graph? If this was a poor attempt at sarcasm or humor, you might want to re-consider your approach.
(Or perhaps the moderators might want to snip this comment AND yours to avoid religious topics that are banned at WUWT.)
Smokey says: “Here is a graph from a completely different and very credible source, which shows the same non-relationship between CO2 and global temperatures.”
Ah! but that is where you are wrong! This graph is much better than the last one.
1) This graph is global temperatures, not US, so it should more closely follow CO2.
2) This graph has about HALF the slopes that the other one did! I specifically commented that your earlier graph was exaggerating the slopes, and this graph provides the confirmation. Thanks.
My one complaint about your new graph would be the odd starting point. I can understand starting the graph when the CO2 data starts — that is logical. But the temperature data is curiously plotted for about a year prior to the CO2 data. And even more curiously, this is about exactly the amount of time the temperatures remain fairly high, including that extra spike to draw the eye upward. If they had added one more year, the temperatures would plunge. If they included yet another year, the temperature would spike lower than any other point on the graph. All of a sudden, that cooling trend from 1957-1976 would not look so robust.
It’s almost as if they cherry-picked the starting date for the temperature data simply to highlight their agenda ….
Tim F says:
“…to avoid religious topics that are banned at WUWT.”
You thought that was religious?? You have no sense of humor. I was just razzing you with a phrase that someone would say to a witch doctor. Mainstream climatology has a witch doctor quality, no? Yes: ‘CO2 is bad juju!’
As for your long, nitpicky criticism of Ole Humlum’s chart, he has dozens of similar charts on his excellent site at http://climate4you.com with lots of different time scales. You should check it out. Might learn something.