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%.
Stephen Walters says:
July 6, 2013 at 12:14 am
Solar cycle 24 will be the lowest cycle in 200 years, nothing like being 100 years out.
If you use the official count [of smoothed values which is the standard way of measuring cycle heights] cycle 24 now stands at 66.9 [and may still go higher – we don’t know], 1906 stood at 64.2, so was lower. If you accept my revised numbers [all values before 1947 increased by 20%], you have to go back to 1816 to find a lower maximum. 1715 – as you said – is off by 100 years.
Patrick says:
July 6, 2013 at 12:19 am
That would be the 1783-84 eruption
No, 1739 is not 1783. But there was also a big eruption in 1783.
The CETs daily maximum is catching up with the long term average:
http://www.vukcevic.talktalk.net/CET-Dmax.htm
currently only -1.1C (May -2.3C) from earlier in the year when it was averaging about -3C on the 20 year (1990-2010) average.
This follows the existing 350 year long behaviour in the CET’s movements:
http://www.vukcevic.talktalk.net/MidSummer-MidWinter.htm
Ergo: nothing new, all seen before.
(p.s. for understanding CET read TonyB and consult the vukcevic’s graphs)
.
Patrick says:
July 6, 2013 at 12:19 am
That would be the 1783-84 eruption
Although Bárdarbunga [Iceland] also erupted strongly in 1739, perhaps the real damage was due to Hekla in the the same year. [ http://runeberg.org/univers/0476.html ]:
Translating from the Swedish:
“One of the most violent eruptions known on Iceland happened in 1739, when lava flows filled the Skapt-ons and Herrfirflojts valleys to a thicknes of 125-190 meter and flowed on for 84 and 34 km and buried [with their estimated volume of 12-15 cubic km] a 500 square km land area. The eruption lasted four months and due to it and the ensuing famine 9,288 people perished or nearly 1/5 of the total population of Iceland, in addition to 53% of the cows, 82% of the sheep and 77% of the horses
66.9 minus 20% (if we accept your low adjustment) puts solar cycle 24 right near solar cycle 5, more than 200 years away. Solar cylce 14 is not lower.
Stephen Walters says:
July 6, 2013 at 1:03 am
66.9 minus 20% (if we accept your low adjustment) puts solar cycle 24 right near solar cycle 5, more than 200 years away.
As I said July 6, 2013 at 12:26 am
lsvalgaard says:
July 6, 2013 at 1:12 am
As I said July 6, 2013 at 12:26 am
So maybe you should drop your silly comparison of SC24 & SC14.
“lsvalgaard says:
July 6, 2013 at 1:01 am”
This is the 1783-84 event I am talking about;
http://www.gso.uri.edu/lava/Laki%20Eruption/Lakierupt.html
Not knowing Swedish or Icelandic, on the surface at least, it sounds like the events were in the same region but at different times yet sound almost identical in terms of damage, lava flow, extent, climatic change and deaths etc.
This event, and effect on local climate, was actually recorded in parts of England. But 1739 did seem to be quite an active year for volcanos.
lsvalgaard says:
July 5, 2013 at 1:47 pm
The bad year 1740 was likely the result of volcanic activity [Tarumai, Japan, 1739 and likely more important for England temperatures: Bárdarbunga Iceland, 1739] so is not predictable.
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There might be one possible way. The three neutron monitor lows shown here,…http://143.160.38.244/webfm_send/42735, line up with El Chichon, Pinatubo, and the Sumatran quake and tsunami. From a peak in late 2009, the stream has decreased steadily, and now looks like it might be headed for the next big drop in about 9 to 10 months from now. You can see that the graph shows moves up to 15 units downward within a years time. Will there be another significant Earth event at that time? Is Mt Lassen ready after 99 years of silence? The other prediction with the neutron low is that the surface sst seems to fit, high to low, with it, also the 0 to 100m. Doesn’t a higher solar output mean a diminished cosmic ray stream?
On a similar vein, Popocatepetl has been erupting strongly for the last 48 hours, along with the Alaskan, Kamchatkan groups. Central American, Fuego, several Columbian plus other SA volcanoes and as of today Lokon Empung in Indonesia are also in different stages of activity or warnings…http://earthquake-report.com/2013/05/27/wordwide-volcano-activity-copahue-volcano-chile-alert-raised-to-red/
leif
Here is CET shown from 1538 (my reconstruction to 1659) in annual, 10 year and 50 year chunks.
http://judithcurry.com/2013/06/26/noticeable-climate-change/
I am not sure the volcano in 1739 had a lasting effect beyond one or two years.
tonyb
Patrick says:
July 6, 2013 at 1:33 am
Not knowing Swedish or Icelandic, on the surface at least, it sounds like the events were in the same region but at different times yet sound almost identical in terms of damage, lava flow, extent, climatic change and deaths etc.
Close, but not quite. Your link says “produced one of the largest lava flow eruptions in historic times. About 15 cubic kilometers of basaltic magma was erupted from the 27 km long fissures”.
The 1739 eruption of Hekla was a bit different [see my translation]. Similar damage might be expected from eruptions from volcanoes so close.
Stephen Walters says:
July 6, 2013 at 1:29 am
So maybe you should drop your silly comparison of SC24 & SC14
The problem with SC5 is that the data is very uncertain [up to a factor of two] so meaningful comparison with SC5 is problematic. SC14 is well-observed.
A plot of the Heliospheric magnetic field shows how close SC14 and SC24 match up to now:
http://www.leif.org/research/SC14-SC24-HMF-B.png so the comparison looks rather good. The difference between the curves is within the uncertainty of the data. If the cycles behave similarly, we might expect SC24 to increase a bit further in 2-3 years, but that is speculation.
climatereason says:
July 6, 2013 at 1:44 am
I am not sure the volcano in 1739 had a lasting effect beyond one or two years.
Your plot shows it did. BTW, use centered running means otherwise you shift the curve.
goldminor says:
July 6, 2013 at 1:35 am
The three neutron monitor lows shown here,…http://143.160.38.244/webfm_send/42735, line up with El Chichon, Pinatubo, and the Sumatran quake and tsunami.
Those are just coincidences. Short-term cosmic ray intensity is determined by the Solar Activity. Several investigations have shown that solar activity is not correlated with earthquakes or volcanic activity.
climatereason says:
July 6, 2013 at 1:44 am
I am not sure the volcano in 1739 had a lasting effect beyond one or two years.
Your plot shows it did. Forgot the plot:
http://www.leif.org/research/CET4.png
The little blips are not climate.
lsvalgaard says:
July 6, 2013 at 1:47 am
A plot of the Heliospheric magnetic field shows how close SC14 and SC24 match up to now:
We were talking of sunspots not HMF.
If you want to quibble we can always go with SC6.
Leif
“No, only 0.05 deg C. The percentage change in temperature will be a quarter of the percentage change in radiation.”
Double that and you are getting closer. Those GHGs you know.
Leif said ” you have to go back to 1816 to find a lower maximum.”
Suggesting that Leif wouldn’t be surprised to see a temperature drop to just above those experienced in the Dalton. This would tie in with a projection (model / graph) I have seen elsewhere, predicting cooling to 2030 ending up at a level just above the Dalton.
IIRC Leif ascribes the cause of this possible event to Jupiter and not the sun.
Stephen Walters says:
July 6, 2013 at 2:13 am
We were talking of sunspots not HMF.</i<
The HMF is a good measure of solar activity [for example controls the cosmic ray intensity] and depends simply on the square root of the sunspot number: as HMF goes, so goes the SSN.
If you want to quibble we can always go with SC6.
Which is not much better as far a reliability goes, but the point is that we should not compare with 1715 as claimed. Perhaps you forgot that…
One attempt to put error bars on the count of sunspot groups [the group sunspot number] looks like this:
http://www.leif.org/research/Error-Bars-GSN.png
As you can see the cycles at both ends and in the middle are very much alike within the error bars. To discuss decimals of the count doesn’t make much sense. SC24 is on par with SC14 whicg is on par with SC5 and SC6. We cannot with any significance claim they are different.
Bravo for a good post that emphasises the difference between playing statistical games with temperature and putting your money on tens of thousands of dollars of seed and fertilizer.
Tony B & Dr. S
CETt did recover quickly after 1739’s eruptions, but it fell back again in the following two decades due to different reasons. I put it down to the tectonic activity around Iceland, which may or may not follow individual volcanic eruptions. I welcome any alternative hypothesis which is supported by known data.
http://www.vukcevic.talktalk.net/CET-NAP.htm
lgl says:
July 6, 2013 at 2:27 am
Double that and you are getting closer. Those GHGs you know.
There is no real difference between 0.05 and 0.1 C. The point is that the change is tiny.
J Martin says:
July 6, 2013 at 2:34 am
Suggesting that Leif wouldn’t be surprised to see a temperature drop to just above those experienced in the Dalton.
Yes I would as the real dip at that time was caused by volcanic eruptions, especially in 1809 (see
Dai JGR 96, 1991), 1814 (Mayon), and 1815 (Tambora).
IIRC Leif ascribes the cause of this possible event to Jupiter and not the sun.
Not quite. Jupiter [with a bit help from the other planets] is the cause of the glaciations during ice ages by changing the Earth’s orbit and tilt thus modulating the solar radiation falling on high latitude Northern Hemisphere land areas. But has nothing to with variations on a time scale of centuries.
lsvalgaard says:
July 6, 2013 at 2:35 am
The HMF is a good measure of solar activity [for example controls the cosmic ray intensity] and depends simply on the square root of the sunspot number: as HMF goes, so goes the SSN.
Overall solar output can be quite different from sunspot values, esp if using the pre 1945 data and looking at grand minimum periods. It is very obvious in regards to sunspot values that SC24 is not resembling SC14. At the present rate SC24 will be the smallest cycle in 200 years, and the climate effects are already being seen. Lucky we are coming off a warm base.
The 1715 argument has no value.
vukcevic says:
July 6, 2013 at 2:59 am
Tony B & Dr. S
CETt did recover quickly after 1739’s eruptions, but it fell back again in the following two decades due to different reasons. I put it down to the tectonic activity around Iceland
The recovery was ‘weather’ just like the blip during the Maunder Minimum. Tectonic activity is defined as earthquakes, volcanoes, and mountain building in general and is not what you may be thinking of. So on Iceland, volcanoes it is.
Stephen Walters says:
July 6, 2013 at 3:04 am
Overall solar output can be quite different from sunspot values, esp if using the pre 1945 data and looking at grand minimum periods.
The solar output before 1976 is constructed from the sunspot values so cannot be ‘quite different’ before that time.
It is very obvious in regards to sunspot values that SC24 is not resembling SC14.
It is very obvious that SC24 strongly resembles SC14.
At the present rate SC24 will be the smallest cycle in 200 years,
The error bars do not allow this conclusion as SC5, 6, 14, and 24 are not statistically different [this means we cannot say which is smaller or larger than the rest].
vukcevic says:
July 6, 2013 at 2:59 am
Tony B & Dr. S
CETt did recover quickly after 1739’s eruptions, but it fell back again in the following two decades due to different reasons.
Likely helped by the strong eruption of Hekla in 1766. There is no need to invoke different scenarios when volcanism will do.
lsvalgaard says:
July 6, 2013 at 3:13 am
It is very obvious that SC24 strongly resembles SC14.
Show us all how SC24 resembles SC14 in regards to sunspots, and please don’t insult us with yearly smoothed numbers.