Fig 3 (Part VI only) Sunspot drawing of by G.D. Cassini in 1671 (Oldenburg, 1671c).
What is surprising is just how much data we have on the Sun from 400 years ago.
For some aspects of solar activity we barely have a half a solar cycle. For example, on solar spectral changes: UV and Infrared light swing up and down through the solar cycle, but we only got a good grip on these important changes in the last ten years with the SORCE mission.
But on other aspects of solar activity there is much more long term data than I expected: 400 years ago quite a few people were carefully recording detailed drawings of sun spots (like Cassini in 1671, right). Others were reporting aurorae — up to 150 a year in parish records, newspaper reports, and scientific observations, which tells us something about the strength of the solar wind. There were also observations of the solar corona during eclipses at the time, which suggest the sun was less active as well.
Lately some (Zolotova et al) have said solar activity was not low during the cold Maunder Minimum period from 1645 – 1715. Usoskin and others have responded [...]
Is this the way the Great Global Warming Scare fades out?
The UK newspapers are full of “Maunder Freeze Coming” as forecast by Ineson et al. Rest assured, the solar-driven-cold is only a local effect, only 0.1C, and only a vague short 20 to 40 winters to come. The Sun, which has been ruled out as a major cause of global warming, is still not a cause of global warming — it’s just a minor technical issue called UV from a local star, which will be affecting an ocean current. Then the Big 6.6 degrees of heatstroke will land upon us.
Britain could be on the verge of a mini Ice Age as the Sun enters a cooler phase, the Met Office warned yesterday.
The last big chill was felt hundreds of years ago when Frost Fairs were held on the frozen River Thames.
However the Met Office said the new freeze will not be enough to cancel out the effects of global warming.
We’ve seen this all before, but not on this scale. If there was a volatility index — like a VIX for climate-PR – it would be setting records. The contradictions [...]
Looks like Scientific American has gone a bit “cosmic”: The Little Ice Age was apparently caused by black death, small pox, and slavery. The theory goes that there was a small spikey dip in CO2 levels in 1610, which was man-made. So hold your breath, that means a whole new era should start from then. This small dip of dubious causality, plus the correlation of oddly unclimatic things like slavery, seems to make the spike worthy of an impressive sciencey title, lo, a new era is born — The start of the Anthropocene.
Let’s not mention that temperatures started falling from 1400 AD. That’s 200 years before the CO2 spike down. Cause and effect are so passe in postmodern science.
Mass Deaths in Americas Start New CO2 Epoch
The atmosphere recorded the mass death, slavery and war that followed 1492. The death by smallpox and warfare of an estimated 50 million native Americans—as well as the enslavement of Africans to work in the newly depopulated Americas—allowed forests to grow in former farmlands. By 1610, the growth of all those trees had sucked enough carbon dioxide out of the sky to cause a drop of at least [...]
Could this be why climate models do rainfall with all the competence of tea-leaf-reading? Tiwari et al report that as much as 47% of the recharge rates of ground water in China are controlled by the sun. Apparently climate models miss the minor factor of the major cycles.
Try this radical idea on: imagine a world where climate models worked. Not only could the BoM warn people that there would be a drought coming, they could name the region, and the years.
Tiwari et al:
Here for the purpose of comparison of long term ground water recharge rates with long term solar activity, we used the 10-year average sunspot time series, for the period 1300 to 1905 AD, published by Solanki et al., . Also the additional average annual sunspot number time series (1700 to 2000 AD) is used from data source Solar Influences Data Analysis Centre. In addition to decadal data annual sunspot number data from 1700 to 2000 AD downloaded from Solar Influences Data Analysis Centre is used in the present study. The cross-correlation coefficient (+0.63) between the groundwater recharge rate time series and decadal sunspot number [Solanki et al., 2004] shows that there is statistically significant solar [...]
A new paper (Moffa-Sánchez et al) reports that they looked at layers of dead plankton in ocean mud (otherwise known as foraminifera in marine sediments) and have reconstructed the temperature and salinity of a couple of spots in the North Atlantic between 818AD – 1780 with data on δ18O and the Mg/Ca ratios. One immediate thought, an aside, is that if this technique works, there is no shortage of ocean mud, surely, and perhaps we could drill and analyze more mud for solar correlations in other places. (I hear foraminifera live in the Southern Hemisphere too). Perhaps no one is looking for the connection with the sun?
Moffa-Sánchez et al find the big climate shifts (the 100-year variations) correlate with total solar irradiance (TSI). See especially that orange line black line track in the d graph below. I stress, correlations don’t mean causation and the mechanism is mere speculation. But I find the graph intruiging. There are a lot of turning points, and in pure “curve fitting” type of analysis, this is a better curve fit than the one with CO2. (Find me a turning point that matches with carbon dioxide!) I suspect we’ll be referring back to this paper, and I [...]
Rosenthal et al have put out quite a humdinger of a paper. They’ve reconstructed the temperature of the water flowing out of the Pacific to the Indian Ocean over the last 10,000 years and as deep as 900m. The Indonesian Throughflow is pretty significant in global ocean currents. There’s narrow routes for Pacific upper waters to squeeze through to the Indian Ocean through the Makassar and Lombok Straits, and via the Lifamatola Passage through the Banda Sea, and water comes in from both the North and South Pacific.
An important point in global ocean currents where the Pacific flows through to the Indian Ocean.
Points to note (assuming the study is right):
Temperatures started rising around 1700AD – long before our carbon emissions. That temperatures were much warmer (0.65C) in 1100AD than they were in 1950. 8,000 years ago water was 1.5 to 2 degrees warmer — isn’t that meant to be a global catastrophe? Apparently coral reefs, fish, and turtles survived.
Figure 4. Holocene changes in Pacific Ocean heat content. (A) Reconstructed anomalies in Pacific OHC in the 0- to 700-m depth interval for the early Holocene, mid-Holocene, MWP, and LIA periods. Reconstructed anomalies are calculated relative [...]
Glaciers that tore trees in half and then froze the stumps are receding again in Alaska to reveal those old remnants of a warmer era. I like these little “concrete” anecdotes, though their true meaning depends on exactly how old these remains are, and whether that timing correlates with warming in other places.
Ancient trees emerge from frozen forest ‘tomb’ Retreat of the Mendenhall Glacier reveals the remains of trees which grew more than 2,000 years ago By MARY CATHARINE MARTIN JUNEAU EMPIRE
The Mendenhall Glacier’s recession is unveiling the remains of ancient forests that have remained frozen beneath the ice for up to 2,350 years.
The most recent stumps she’s dated emerging from the Mendenhall are between 1,400 and 1,200 years old. The oldest she’s tested are around 2,350 years old. She’s also dated some at around 1,870 to 2,000 years old.
Thermometer circa 1790
UPDATED: Post note below, with a couple of extra caveats…
Lüdecke, Hempelmann, and Weiss found that the temperature variation can be explained with six superimposed natural cycles. With only six cycles they can closely recreate the 240 year central European thermometer record. There is little “non-cyclical” signal left, suggesting that CO2 might have a minor or insignificant effect.
The three German scientists used Fourier analysis to pick out the dominant cycles of one of the longest temperature records we have. The Central European temperature is an average of records from Prague, Vienna, Hohenpeissenberg, Kremsmünster, Paris, and Munich.
The dominant cycle appears to be about 250 years. There is also a cycle of about 60 years, corresponding to the Atlantic/Pacific decadal oscillations.
Data is of course, always the biggest problem. If we had 10,000 years of high quality global records, we could solve “the climate” within months. Instead, we have short records, and Lüdecke et al, make the most of what we have. The European records are only 240 years long, or (darn) one dominant cycle, and only one region, so to check that the results are valid over longer periods they also analyze a the 2000 year Spannagel Cave [...]
There have been suggestions that Jo Nova might be trying to hide or ignore the most recent boreholes graph from Huang et al. So here it is. This is the last 2,000 years according to 6000 boreholes, with the last 100 years also using the “instrumental record” which gives us that hockey-stick uptick at the end. Below I explain the pros and cons of this study and update my thoughts.
Huang and Pollack 2008: Their latest boreholes published study
A borehole sounds like a bit-of-a-stretch as a proxy. How could we tell if the world was warmer in 1066 by drilling a hole in the ground? Yes, fair point. But what makes boreholes useful is that they are global and there is a lot of data: specifically 6,000 holes all over the world.
I’ve been looking at boreholes in more detail, analyzing them in the light of newer proxies. When all the evidence is considered, boreholes turn out be not-much-use at giving us meaningful numbers in degrees C, and in my opinion, not-too-hot at telling us the “when” of an event either. Too much depends on assumptions.
But what are they good for is that, when combined with [...]
Two major proxy studies, larger than ever, were released in April and June 2012. They show that the Medieval Warm Period (MWP) existed, and was similar to current temperatures. These comprehensive studies suggest current temperatures are not unusual, and that itself is not all that surprising — I’ve mentioned before how there are hundreds of proxy studies showing it was as warm or warmer back then. (CO2science has been documenting them.) But these studies are worth a mention because they are so large.
Climate models cannot explain what caused the warming 1000 years ago, nor the cooling 300 years ago, so they can’t rule out the same factors aren’t changing the climate today (though they claim they can). If climate models can’t explain the past, they can’t predict the future.
The last 12 Centuries
Ljungqvist used 120 proxy records — nearly 3 times as many proxies as previous studies and conclude: “during the 9th to 11th centuries there was widespread NH warmth comparable in both geographic extent and level to that of the 20th century”. Their proxies included ice-cores, pollen, marine sediments, lake sediments, tree-rings, speleothems and historical documentary data.
Ljungqvistet al 2012 Fig. 4. Mean time-series of centennial [...]
21 contributors have published
2242 posts that generated