Baghdad gives up historical climatic clues

From the FECYT – Spanish Foundation for Science and Technology

Arabic records allow past climate to be reconstructed

The study has been published in Weather, a publication of the Royal Meteorological Society

Corals, trees and marine sediments, among others, are direct evidence of the climate of the past, but they are not the only indicators. A team led by Spanish scientists has interpreted records written in Iraq by Arabic historians for the first time and has made a chronology of climatic events from the year 816 to 1009, when cold waves and snow were normal.

The Arabic historians’ records chronologically narrate social, political and religious matters, and some of them mention climate. A study led by researchers from the University of Extremadura (Spain) has focused on ancient meteorological notes of the Iraqi city of Baghdad.

“We have recovered an interesting chronology of climatic events, such as droughts, floods, rain, frost, heat and cold waves as well as strong winds during the period between 816-1009 in the areas now known as Iraq and Syria” Fernando Domínguez-Castro, lead author and researcher in the Physics department at the University of Extremadura, informed SINC.

This study, which has been published in the Weather journal, highlights a high number of cold waves. “The period between 902 and 944 had a high number if we compare them to current weather data. Examples of this are the six snowfalls that occurred in that period, whilst in our era, we only know of one snowfall in Baghdad on 11 January 2008” Domínguez-Castro highlights.

More cold days due to volcanic eruptions

The research team was especially surprised by the “unexpected” drop in temperatures in July 920. According to the documents analysed, the people of Baghdad had to come down from their roofs (where they would usually sleep in the summer) and go inside their houses and even use blankets. The temperatures could have dropped 9ºC compared to the current average for the month of July.

“It is difficult to identify the cause of this drop in temperature, but it could be due to a volcanic eruption the year before, as it is common for summer temperatures to drop in these cases” the expert points out and says that during some of those nights in July 920, temperatures did not exceed 18ºC.

There were two significant volcanic eruptions during that period, which could be the cause of the cold waves, “although there is a lot of doubt surrounding the dates”, the researcher states. One of those was the Ceboruco volcano (Mexico), around 930, and the other was the Guagua Pichincha (Ecuador), around 910. Nonetheless, “more evidence is necessary to confirm this hypothesis” the expert warns.

The research shows that during the first half of the tenth century, the cold climatic events in Baghdad were more frequent and more intense than today. Although in the Iraqi city only two days with temperatures below 0ºC were registered between 1954 and 2008, there were at least six very cold days in a 42 year period in the tenth century.

According to the researchers, “the Arabic records are very useful for reconstructing the climate in eras and places about which we know very little”. Thanks to the synergy of humans and science ‘robust climate information’ has been extracted” they conclude.

Baghdad, the centre of the empire

In 762, Abu Ja’far Abdallah al-Mansur, the second Abbasid Caliph (the second Islamic dynasty), founded the city of Baghdad and established it as the capital of the empire. The city soon became the most prosperous place at the time, and the centre of international trade and agricultural development, which attracted a growing population.

Historians of the era debated reasons as to why the Caliph gave so much importance to Baghdad. As well as its strategic location between the Tigris and Euphrates rivers, the city had good weather conditions. “There was plenty of water, the weather was very warm in the summer, very cold in the winter, and moderate in spring and autumn,” Al-Ya`qubi described, author of a geographical treatise in 891.



Domínguez-Castro, Fernando; Vaquero, José Manuel; Marín, Manuela; Gallego, María Cruz; García-Herrera, Ricardo. “How useful could Arabic documentary sources be for reconstructing past climate?” Weather 67(3): 76-82 DOI: 10.1002/wea.835 march 2012

Link to abstract:


17 thoughts on “Baghdad gives up historical climatic clues

  1. Interesting. I wonder why the analysis was confined to that particular window, though. I would have expected records that spanned hundreds of years, at least up to the fourteenth century.

  2. Interesting study, but I have it on good authority that every day prior to the development of the internal combustion engine was 70 degrees Fahrenheit, worldwide, with a gentle breeze and the ideal amount of precipitation falling in the overnight hours so as not to disturb anyone’s day. Since the internal combustion engine, though, it has been all climate change all the time.

  3. Gotta ask: What is the timing uncertainty on the Bagdad 920 AD cold spell? is it well locked by eclipses or is a more indirect dating?
    Also, is there any reference to crop failures or famines associated with any of the years?

  4. Cold weather is very good for controlling diseases. The Big freeze sterilizes everything once each year.
    Otherwise why would someone choose a cold winter place when they could have warm? After all, why do Americans have warm America, and Canadians, cold Canada? Because the Americans got to choose first.

  5. Stephen Rasey says:
    “Gotta ask: What is the timing uncertainty on the Bagdad 920 AD cold spell? is it well locked by eclipses or is a more indirect dating?”
    I imagine chroniclers in Baghdad were literate people who recorded the year based on the Hegira (Mohammed’s journey from Mecca to Medina in 622 AD), a meticulously kept chronology throughout the Islamic world. There shouldn’t be a need to use astronomical confirmation.

  6. It’s not much use comparing Baghdad in 920 with modern Baghdad because of the urban heat island effect. It’s like comparing apples to maggot-eaten apples.
    Also, they quoted 2008 as an endpoint in the study. What happened in 2012 (yes, this year), when eastern Europe and Asia Minor had a bitter winter? Did Baghdad, or more importantly villages near Baghdad, have any sub-zero days?

  7. @Stephen Rasey: I decided to buy the paper, because it strikes several of my interests at once. (Climate, Arab scholars, old metrology).
    It’s sort of disappointing, not really worth the price.
    Dating was done by astronomy, known political events, and comparison with other texts. The chroniclers gave precise dates by their local calendars, but apparently those calendars were not standardized across the Muslim world, and tended to slip at times.
    The original Baghdad chroniclers were mainly thinking of agriculture, so they did list crop failures along with hailstorms, snowstorms, floods, droughts, locusts, etc. But the paper’s authors were focusing tightly on cold spells, so they didn’t say much about that.
    For me the most interesting part was the precise use of freezing points by the chroniclers. Without thermometers, they used the freezing of vinegar, grapes, rivers, small cisterns, large cisterns, etc, as consistent measuring marks.

  8. Doug Proctor says:
    April 30, 2012 at 1:04 pm
    Cold weather is very good for controlling diseases. The Big freeze sterilizes everything once each year.
    So true. Mild winter in Texas, hence the recent Mothmageddon we’ve had. Moths invading houses, radio studios, every other mailbox I opened had a cloud of moths fly out at me.

  9. So when will they look into how many days after the solstice the cherry trees blossomed Japan over time (an event of great social significance each year) or how orange orchard production varied over time and spatially in China? Nations that have had bureaucrats for over a millennium will have all sorts of information that can be dug through. Unless, of course, they don’t match the narrative. In that case, “my dog ate the records”.

  10. Mike D in AB says:
    April 30, 2012 at 6:12 pm
    So when will they look into how many days after the solstice the cherry trees blossomed Japan over time>>>>
    Check out papers by Aono. Some excellent reconstructions going back to that time period based on cherry blossom dates. There’s even a couple of papers using cherry blossom dates in Japan to quanitfy UHI.

  11. Is a publication called “Weather” actually confusing weather with climate? I used to think I understood the difference but now I am confused. Is the difference that it is “weather” if it contradicts global warming theory and “climate” if it supports it? Or is “weather” a “climate event” as described in the article?
    Some time ago I heard that in a debate if you are weak in the specific you should argue the generality and if weak in the generality argue the specific. Perhaps the warmers have adapted that idea to weather and climate. And then to really confuse the rest of us they have invented “climate event” which perhaps falls somewhere in the middle.

  12. It seems to me a shame that this article attracts little interest in substance on this blog. Perhaps the Middle East is too far from home. At the time involved (800-1000) the Arabic world kept the best records available. The Arabic calendar is not exactly inaccurate, and the observational records have a local meaning which cannot be replaced by other methods of dating and estimation. Surely we should be keeping records per year and per geographical area based on actual historical events? At the very least, these act as a sanity check for the climate “reconstructions” foisted on us by climate ideologists: at best they can expose attempted lies.
    So, I welcome this paper and this post.

  13. Of all the claims by the Climate community, the one I find most unbelievable is that they can reliable determine temperatures going back hundreds of years with sufficient accuracy that they can now argue over tenths of degrees. In situations where the temp was recorded, there are questions about the accuracy of the device and the veracity of the recorder (how much “good enough recording went on). For temps determined by proxies I am skeptical that any of them can determine temps to a tenth of a degree, or even within several degrees.
    The premise that they can know these things with such precision is the foundation upon everything else is built.
    Has there ever been much discussion about the technical details and methodologies they used to derive these temps (disregarding the controversy over heat islands, etc.)?

  14. sycodon says:
    May 1, 2012 at 1:08 pm
    …..The premise that they can know these things with such precision is the foundation upon everything else is built.
    Has there ever been much discussion about the technical details and methodologies they used to derive these temps (disregarding the controversy over heat islands, etc.)?
    Yes, quite recently too.
    Global annualized temperature – “full of [snip] up to their eyebrows”
    By occasional WUWT commenter AJStrata: Alarmists Hide Truth About (Lack Of) Global Warming: Analysis of error in temperature measurements
    An Ocean of Overconfidence
    Australian temperature records shoddy, inaccurate, unreliable
    Another GISS miss: warming in the Arctic – the adjustments are key

  15. Looking at the history of temperatures and weather variation is very interesting. There is a 1500 ish year cycle of Bond Events. Extreme cold excursions. These are often preceded by a “warm spike” of about 40 years duration. In ‘digging into it’ I found what looks like a pattern of cooling, but not as drastic as the Bond Events, that happens at about a 1/2 Bond Event interval of 700 ish years.
    The Dark Ages began in 535 AD or so and that cold spike ran to about 1000 AD when things warmed to a peak in about 1300 AD in the Medieval Warm Period. That’s about 1100 years after the Roman Warm Period peak in 200 AD, so doesn’t quite fit the 1/2 Bond Event pattern. Then again, the ‘rollover’ in 535 AD looks to be correlated with some kind of major volcanic or meteor event that messed things up.
    At about 200 BC the Greeks where having a good time during a cold period (that was giving their neighbors fits) and 720 ish years later, in 535 AD a major drop happens, so close to a 1/2 Bond Event. In about 1300 AD plus a bit, or 800 years later (or think of it as 2 x 750 ) we have the plunge into The Little Ice Age. Add 720 to that (1/2 a Bond Event, more or less) we get 2020 AD. Just Saying…
    I suspect the actual offsets are not so regular. The average Bond Event is 1470 years, but with some tendency to have the actual dates displaced to one side or the other ( rather like sunspots where the average is 11 years, but the reality is more often 10 ish or 12 ish ) so some ‘jitter’ around the period is to be expected.
    So these records from Baghdad start during a cold period (the climb out of The Dark Ages) and reach to the start of a warm run (up to the MWP). Not that surprising that they have more snow, and some warmth. About what I’d expect from that time window.
    There are other bits of history too. Periodically cold and drought leads to the collapse of Egypt and shifts the balance of power between The Levant and Southern Europe. Yes, I said periodically. Look at history and it shows those cycles clearly. Driven by famine, drought, and cold. FWIW, China, too, has periodic famine and drought in cold excursions. There are many such patterns to history. “Climate” is anything BUT stable.
    makes a very odd pattern…
    has a very nice image of the way “climate” can wobble back and forth dramatically and has in the past:
    Note the dramatic swings of 1-2 C in 50 year type spans. It clearly shows the plunge about 535 AD ( 1477 BP) and the equally dramatic rise from a bottom about 1200 BP to 1000 BP. (roughly 800 AD to 1000 AD).
    It is the notion that Climate has some stable norm that is broken. It wobbles about, jumping and plunging by a couple of C at a time. Always has. Often a rise of a degree or two C over about 40 years precedes a major plunge into “way cold”.
    Have I mentioned that we’re just about on cycle for a Bond Event now? 535+1470 = 2005 But it can have a 100 years error band… so maybe not for a couple of more decades…

  16. Mike Bromley the Canucklehead says:
    April 30, 2012 at 12:58 pm
    rgbatduke says:
    April 30, 2012 at 12:44 pm
    Oh please, the Mesopotamians were cherry-pickers, too, dontcha know.

    Nah, they didn’t give a fig for cherries. Or rather, they could give you thousands of figs for every cherry!

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