Guest essay by David Archibald
This post drew attention to the similarity between the recent warm decades and the period leading up to the extremely cold year of 1740. Now let’s investigate how a 1740-type event might play out. This graph shows the average of the monthly temperatures for the years 1736 to 1739 plotted with the monthly temperatures of the year 1740:
With respect to growing conditions, the 1740 season was a month later than the average of the previous five years and the peak months of the season were 2.5°C cooler. To get a perspective on how a repeat of 1740 might affect growing conditions in the Corn Belt, Bill Fordham, advising the grain industry in the Midwest, has kindly provided an update on the current season:
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“So far here in the center of the Midwest, the 2013 growing season is almost identical to 2009 in regards to Growing Degree Days (GDD).
In 2009 48% of the corn was planted by May 12 and 62% was planted by May 19.
In 2013 18% of the corn was planted by May 12 and 71% was planted by May 19.
In 2009, we never received a killing frost until November 5 when the low was at 28F. The Midwest had a huge crop that was wet and light test weight, but never got killed by a frost. In 2009, the total GDD accumulation from May 15 thru September 30 was 2,530 GDD.
The bulk of the corn planted in the Midwest ranges from 2,300 to 2,700 GDD (based on Fahrenheit). With the volcanoes that have been erupting in Alaska and Russia, especially with Mt Sheveluch erupting to 7.4 miles on June 26, I will be surprised if we get through the month of September in 2013 without an early killing frost. If the heat dome and high pressure ridge stays centered in the west and over Alaska until Labor Day, the clockwise rotation will pump the cold air south over the Midwest along with the ash. There are millions of acres at risk in IA and MN, that are 2-3 weeks behind normal.
After silking, it takes 24-28 days to reach the Dough Stage when kernel moisture is about 70% and about 50% of the total dry matter has accumulated in the kernel.
After silking, it takes 35-42 days to reach the Dent Stage when kernel moisture is about 55% and about 70% of the total dry matter has accumulated in the kernel.
It takes about 55-65 days after silking for a corn plant to mature and for the kernel to reach black layer, normally at 30-35% moisture.
A killing frost, <30F, will do damage whenever it occurs before black layer, the earlier the frost, the more severe the damage. A hard killing frost <28F can reduce the yield up to 25%, or more depending on the variety, even a week before black layer.
In 1974 I experienced severe loss on some late planted corn when I got rained out on May 7 and didn’t get back in to finish planting for 3 weeks. The May 7 corn yielded 190 bushels per acre and the May 28 corn yielded 90 bushels per acre, same variety.”
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Based on Bill Fordham’s experience of 1974, planting three weeks later reduced the crop yield by 50%. If the peak growth months of June, July and August are 2.5°C (4.5°F) cooler as per the CET record of 1740, that would reduce the GDD by 414.
A repeat of the climate of 1740, with a late planting and reduced heat in the three months prior to harvest can be expected to reduce crop yield by well more than 50%.
“J Martin says:
July 6, 2013 at 2:34 am”
There maybe an influence, but we really don’t know for sure. It’s another theory. We can be confident that our emissions of CO2 cannot be driving change in climate in any significant, or bad, way.
lsvalgaard says:
July 6, 2013 at 3:16 am”
And yet, alarmists state there is no effect.
lsvalgaard says:
There is no need to invoke different scenarios when volcanism will do.
Volcanism is certainly more convenient.
Stephen Walters says:
July 6, 2013 at 3:28 am
Show us all how SC24 resembles SC14 in regards to sunspots, and please don’t insult us with yearly smoothed numbers.
Yearly smoothed sunspot numbers are the yardstick by which solar cycles are measured so you will have to endure the ‘insult’ at some point. But here is a comparison of daily numbers: http://www.leif.org/reseach/SC14-and-SC24-overlap.png
A recent reconstruction of the number of sunspot groups is not sensitive to the Waldmeier sunspot weighting and thus has no issue with ‘corrected’ data. It also has error bars that reflect the 1-sigma confidence. We can compare SC5, 6, 12, 14, 16, and 24 http://www.leif.org/research/Sunspot-Groups-Small.png and you can judge for yourself how SC24 compares and report here what you found.
http://www.leif.org/research/SC14-and-SC24-overlap.png
Bruce Cobb says:
July 6, 2013 at 3:54 am
“There is no need to invoke different scenarios when volcanism will do.”
Volcanism is certainly more convenient.
Occam’s razor: “Entities should not be multiplied unnecessarily” or in his own words: “pluralitas non est ponenda sine neccesitate”.
lsvalgaard says:
July 6, 2013 at 3:57 am
Yearly smoothed sunspot numbers are the yardstick by which solar cycles are measured so you will have to endure the ‘insult’ at some point.
Very predictable….keep trying you will have to do better than this smokescreen.
Stephen Walters says:
July 6, 2013 at 4:08 am
Very predictable….keep trying you will have to do better than this smokescreen.
The ‘smokescreen’ is how it is done. But here is a comparison of daily numbers: http://www.leif.org/research/SC14-and-SC24-overlap.png
A recent reconstruction of the number of sunspot groups is not sensitive to the Waldmeier sunspot weighting and thus has no issue with ‘corrected’ data. It also has error bars that reflect the 1-sigma confidence. We can compare SC5, 6, 12, 14, 16, and 24 http://www.leif.org/research/Sunspot-Groups-Small.png and you can judge for yourself how SC24 compares and report here what you found.
lsvalgaard says: Occam’s razor
Same argument Warmists use for CO2. It’s so simple: CO2 goes up, and temperatures do likewise. It’s just basic physics and chemistry! Why can’t we skeptics get that?
Bruce Cobb says:
July 6, 2013 at 4:26 am
Why can’t we skeptics get that?
scientific illiteracy, perhaps?
lsvalgaard says:
July 6, 2013 at 3:16 am
Likely helped by the strong eruption of Hekla in 1766. There is no need to invoke different scenarios when volcanism will do.
Volcanic eruption is a short term (one-two years) direct atmospheric negative forcing.
Tectonics is indirect positive forcing acting via ocean currents
http://www.vukcevic.talktalk.net/CET-NAP.htm
Why do I assume that?
Correlation with SST is higher than with the land temperatures
http://www.vukcevic.talktalk.net/SST-NAP.htm
since integration (cumulative effect over period of time) and a delay are involved than it has to be a ‘climate’ not a day to day ‘weather’ forcing factor.
Is this found elsewhere ?
Yes, in both the N. Pacific (PDO)
http://www.vukcevic.talktalk.net/PDOt.htm
and in the central Pacific (ENSO) areas
http://www.vukcevic.talktalk.net/ENSO.htm
Is there a solar activity connection?
There is a strong correlation with the SSN count since 1880s, and somewhat sporadic going back to 1600, but only in the N. Atlantic.
http://www.vukcevic.talktalk.net/SSN-NAP.htm
Thus I conclude:
There is urgent need to invoke different scenarios, and volcanism alone will not do!
Dr. S, your observation is wrong, dogmatic and contrary to the good science practice.
Leif
Thanks for your earlier comment. This extract comes from personally researched material from the archives of Exeter Cathedral where they noted all annual expenditures for auditing purpose
1740 January ‘£23 to be given to poor in consideration of the severity of the season.’
1783 ‘Extra poor relief in extreme cold’ (due to Iceland volcano?)
I
am not sure there is much evidence of long lived volcanic effects apparent in any archives I have seen.
Do you have a view of the eruption noted by DR Mann in the middle of the 1200’s?
Also in my previous link I had noted annual, decadal and fifty year figures. (Figure 4) The purpose was to examine this data not, on this occasion to plot a 5 year running figure.
Paleo reconstructions tend to be 40 year smoothed figures and appear to completely miss the considerable decadal variability. Using the 40 year figures give the impression of much greater climate stability than actually exists in the real world. I would be pleased to have your comments on this. Thanks.
tonyb
CO2 goes up, and temperatures do likewise. It’s just basic physics and chemistry! Why can’t we skeptics get that?
lsvalgaard says:
scientific illiteracy, perhaps?
gees have you been inhabiting SkS again??? That’s the sort of puerile response one expects from Cook or Lewy !!!
Will be slightly interesting to see how Leif responds if the global atmospheric temperature start dropping and there are no major volcanoes. 😉
This is too funny. David Archibald writes the article, but Dr.Leif Svalgaard takes all the questions.
In June 2013, the SORCE TIM instrument recorded TSI at 1361.42 W/m2.
We are right at the peak of the solar cycle now and it should be recording 1361.75 W/m2 (about 0.5 W/m2 higher than the average, average of 1361.25 W/m2).
So, we are down about 0.3 W/m2 from what would be expected, but it is stil 0.17 W/m2 higher than normal given the solar cycle.
http://lasp.colorado.edu/sorce/total_solar_irradiance_plots/images/tim_level3_tsi_24hour_3month_640x480.png
lsvalgaard says:
July 6, 2013 at 4:11 am
The ‘smokescreen’ is how it is done. But here is a comparison of daily numbers: http://www.leif.org/research/SC14-and-SC24-overlap.png
Very poor graph for a man of your talents, very hard to see any detail. But even so it is clearly evident that SC24 does not have the big swings that SC14 experienced, and as discussed SC14 is higher than SC24.
Why don’t you show us a proper graph with clear detail so we can clearly pull your argument apart?
dbstealy,
Warming or cooling is beside the point. Wiggle-matching is easy, but pretty empty, especially with the poor correlation this post is based on (look at the original post linked to in the article).
Dr Svalgaard, in your graph of GSN with error bars, aside from the earlier cycles the bars seem to be entirely on the more stable periods around the peak. Are you more confident of recorded numbers during the rise/falls? Why?
I’m in central MN, a rather long state, fairly near the northern margin for corn. Virtually none of the corn is “knee high by the 4th”. While we are warming of late, insolation is still well behind my experience for the season. Killing frosts in mid-October are not uncommon here.
The price of corn futures has begun to reflect the risk the crop currently experiences. Soy beans are also behind.
***
bones says:
July 5, 2013 at 9:11 pm
I agree that TSI variations are unlikely to have directly caused the LIA, but I am reluctant to think that the sun played no role.
***
Why? 20k yrs ago, the earth was in the grips of the last glacial maximum — now practically all those glaciers have vanished. The sun itself had essentially the same output in both cases.
“FerdinandAkin says:
July 6, 2013 at 4:44 am”
Something to prove, disprove maybe?
Back to the crop production comparison of 1740 vs 2013, would the enhanced crop yield effect of atmospheric CO2 of 400ppm now versus about 280ppm in 1740 be factored in?
“lsvalgaard says:
July 5, 2013 at 7:48 pm
tchannon says:
July 5, 2013 at 7:25 pm
http://lasp.colorado.edu/sorce/data/tsi_data.htm
Is based on an obsolete paper by Wang, Lean, and Sheeley from 2005.”
Simply look at the plot. It contradicts what you claimed. I already knew that so if you didn’t I am astounded.
Regarding the eruption of Tambora in 1815, much ado is made about the “year without a summer” that followed in 1816, however it should also be noted that there apparently was a lot of arctic ice melt, which doesn’t exactly fit the “volcanoes make it colder” idea.
The quote from John Daly’s site that we all know and love, which begins, ““It will without doubt have come to your Lordship’s knowledge that a considerable change of climate, inexplicable at present to us, must have taken place in the Circumpolar Regions, by which the severity of the cold that has for centuries past enclosed the seas in the high northern latitudes in an impenetrable barrier of ice has been during the last two years, greatly abated…” is dated November 20, 1817.
I wonder, was the AMO was warm, and the volcano prompted a surge of that warmth north?
I imagine good meteorologists know a volcano will throw patterns and cycles out of whack, and are very alert for changes in the expected cycles and patterns, after a big eruption. However I feel that, at this point, the exact nature of the changes are only guesswork.
Much of the late planting this year in parts of the midwest in which we have family was due to wet field conditions precluding getting into the field to plant. There are, again, a multitude of variables which can cause a reduction in yields. Early snows are another or late summer rains, can delay harvest, etc. Fall plowing, where practiced, can even be negated if fall and spring are both wet. Don’t really see much value in this article. Again trying to predict the unpredictables of a chaotic system.