How Japan’s ancient trees could tell the future

From The BBC

At his laboratory in a wooded grove in northern Kyoto, Takeshi Nakatsuka holds up a vacuum sealed bag. Inside, bobbing in a bath of brown water, is a glistening disk the size of a dinner plate and the color of rich gravy. This soggy circle is the remnants of a 2,800-3,000-year-old tree, recovered from a wetland – water included, so the spongy wood does not deform – in Japan’s Shimane Prefecture, just north of Hiroshima. Within this ancient trunk lie secrets that can help us prepare for the future.

Nakatsuka, a palaeoclimatologist at Japan’s Research Institute for Humanity and Nature, along with a diverse team of 68 collaborators, has spent the last decade developing a novel method to reveal bygone precipitation patterns and interpret their effect on society. The results offer unprecedented insight into 2,600 years of Japanese rainfall patterns. By teasing out information locked inside the preserved wood of ancient forests, they are able to reveal just how much rain fell around the country over the past two and half millennia. It is an extraordinary record.

About every 400 years, the researchers found, the amount of rain falling on Japan would suddenly become extremely variable for a period. The nation would toggle between multi-decadal bouts of flood-inducing wetness and warmer, drier years that were favorable for rice cultivation. As the rains came and went, Japanese society prospered or suffered accordingly.

Takeshi Nakatsuka with a 2,800-3,000 year old tree stump (Credit: Rachel Nuwer)

Palaeoclimatologist Takeshi Nakatsuka is using information preserved inside ancient tree stumps to learn about Japan’s climate in the past (Credit: Rachel Nuwer)

“Multi-decadal variability provides us with the chance to transform as well as the chance to collapse,” Nakatsuka says. Regardless of the outcome, he emphasises that such change caused large amounts of stress for the people who lived through it.

As weather patterns today increasingly defy expectations, this window into past climate variability hints at what may be in store for us in the coming years

As weather patterns today increasingly defy expectations and extreme events become more frequent and severe, this window into past climate variability hints at what may be in store for us in the coming years. “Today is not different than 1,000 or 2,000 years ago,” Nakatsuka says. “We still have the same lifespans and we are still facing large, stressful multi-decadal variation.”

Nakatsuka builds a picture of what happened in the past using a number of proxies, including tree rings, corals, stalagmites, ice cores and sediment. But his latest findings, which he and his colleagues are currently preparing for publication, primarily rely on a new method that uses isotope ratios contained within wood to estimate precipitation patterns.

Central Japan is a perfect location for such a study because of the multitude of hinoki, a type of long-lived cypress. Nakatsuka’s study includes data from 68 hinoki, whose samples he sourced from living trees, buried logs, wooden temples, coffin boards and more. All of the wood ranged in age from 100 to 1,000 years.

The ratio of oxygen isotopes in the tree rings within the wood help to link it to environmental conditions in which it grew. On dry days, leaves lose more water and are left with a higher isotope ratio than on wetter ones, helping to give information about the relative humidity in the atmosphere.

“This is a very simple but very strict relationship,” Nakatsuka says. Modern meteorological databases confirmed that the isotope ratios of the most recently-lived trees in his dataset did indeed provide an accurate read on summer precipitation.

Japanese cypress trees (Credit: Getty Images)

Hinoki, a type of long-lived cypress that grows in many parts of central Japan, record the yearly changes in rainfall (Credit: Getty Images)

Isotope signatures, it turns out, also serve as time’s fingerprints: they are unique to the year in which they were created. Nakatsuka worked backwards, starting from a living tree whose age he knew. He used archeological and historic clues to approximate the centuries in which new tree samples lived. He then lined up their individual isotope signatures with other trees in his database that lived around the same time until he found the matching, overlapping pattern they shared. In this way, he stitched together a cohesive timeline from 600 BC to 2000 AD, creating a master chronology.

“Every tree in the master chronology is connected to the present,” Nakatsuka says. “It’s very accurate but time consuming and extensive work compared to traditional tree ring studies.”

While his timeline was able to reveal the erratic rise and fall of precipitation levels every 400 years or so, it didn’t tell Nakatsuka anything about what caused these oscillating patterns. The changes in rainfall he saw occurring every few decades closely matched previous data from conventional tree ring studies, though, and the multi-centurial and millennial patterns also lined up well with many previous reconstructions of past temperature fluctuations in East Asia and the world.

Collaborating with archaeologists and historians, Nakatsuka has been able to unravel what effect these changes in rainfall had on the people who lived at the time. Rainfall patterns over shorter and longer timescales corresponded, for example, to medieval ceremonies led by celebrity priests who prayed for rain. The development of irrigation systems and cooperative groundwater technologies meant to protect against drought also occurred at times when his record showed rainfall was low. As did the creation of government policies designed to rescue subjects from starvation during periods of famine. Most importantly, multi-decadal rainfall fluctuation neatly bookended major epochs in Japanese and Chinese history.

We archaeologists thought of the state formation process mainly in terms of social change, but now we can understand that floods are the background of such social change – Kunihiko Wakabayashi

“Before Nakatsuka’s analysis, we archaeologists thought of the state formation process mainly in terms of social change,” says Kunihiko Wakabayashi, a prehistorical archeologist at Doshisha University in Kyoto, who studies distributions of ancient human habitats around Osaka. “But now we can understand that floods are the background of such social changes.”

During the Yayoi period (1000 BC to 350 AD), for example, most human settlements near the Yoda River in Central Japan occurred in lowland delta areas. Rice cultivation began at that time and became a central part of life. People built peat homes alongside small rice paddies and tended to their plots individually. If waters shifted, people simply moved their homes to a nearby site, avoiding any large-scale upheaval.

A graduate student slices wood into thin samples (Credit: Rachel Nuwer)

By slicing the wood into thin samples, the researchers can extract cellulose for isotope analysis (Credit: Rachel Nuwer)

Read the full story here.

HT/Michael S

54 thoughts on “How Japan’s ancient trees could tell the future

  1. What n o SUV’s found in the samples.

    One hopes that the Japanese are far more honest in their research than their “Western” counterparts.

    MJE

    • No idea about this team but Japan seems to have enough of its own AGW zealots. This is not just a western affliction.

    • One hopes so but you do have this usual nod to CAGW.

      As weather patterns today increasingly defy expectations and extreme events become more frequent and severe, this window into past climate variability hints at what may be in store for us in the coming years. “Today is not different than 1,000 or 2,000 years ago,” Nakatsuka says. “We still have the same lifespans and we are still facing large, stressful multi-decadal variation.”

      James Bull

    • One of the problems with denigrating all climate research is that you get to deny the stuff that actually helps defeat the warmists’ propaganda. This research on tree data and climate variability definitely doesn’t support climate alarmism in its most recent form.

      For the last 14 years since the big uptick in 2004 of Atlantic hurricanes landfalling in the US, the big claim of the warmists is that CO2 induced warming produces climate extremes, not just warming.

      This research seems to pretty clearly show that climate variability (including significantly impactful extremes) itself varies on predictable multi-decadal and multi-century timescales, and is certainly nothing “new” or associated with any particular CO2-induced phenomenon.

      In other words, high or even extreme climate variation is nothing but ordinary and to be expected with or without high CO2.

      There is actually a great deal of very useful and enlightening climate research going on today, and a good deal of it gets posted here at WUWT.

      Don’t be a knee-jerk. Read each post and judge it on its own merits. Some of the stuff posted here is just the usual warmist drivel, but there is also some very good and useful stuff posted too. And it need not be anything that is patently “political” – in fact good science is never political .. good science is just hypotheses, experiments, data, and well supported conclusions.

      Discriminate.

  2. I’m a bit more willing to accept tree rings as a proxy for rainfall than I am for temperature. After all, trees are just water held together by bits of cellulose. One or two degrees C or F aren’t going to make a heck of a lot of difference, but two or three or more inches of rain above or below the ideal will make a difference.

    This is the first I’ve heard of tree rings being studied as proxy for rainfall. I’ll have to let it percolate.

    • Trees react to both temperature and humidity ( like most forms of plant growth ). This is why they had to “hide the decline” in Briffa’s tree ring proxy data.

      • much more sensitive to humidity and nutrients … if there are nutrients and water, trees grow there not matter the temperature … no water, no nutrients, no trees even if it is warm …

  3. Unless I missed it, there was no mention of man made climate change that was going to destroy everything on the planet. Refreshing

    • He did say as extreme events become more frequent and severe. He did not say climate change directly because climate change is a given.
      It is so deemed and the consensus in it no longer needs to be said in mere mortal words.

      • I would love to see a graph of the rain patterns from this study. As in where would it place the shift points of the around 400 year pattern in relation to where we are today?

      • This is what John “Rommel” Cook classifies as “implicit” support of AGW. If the abstract does not explicitly say they oppose AGW hypothesis, they accept it. Hence 97%.

    • Would that match the cooling trend over the last few thousand years I’ve seen in several graphs published on various blogs in the last few days?

      • Somewhere I read once, the several Troy has been left not only because of war attacks but also because of a sometimes longer missing of mediterranian monsum and the resulting longer drying out of the region.

          • Our post glacial climate is far from being as stable as commonly claimed. For this, German geoscientists are now providing new evidence. They studied marine deposits from the northern Red Sea and found that a few thousand years ago, the area, which is now very dry, was characterized by a long wet period – a monsoon-like weather system. A climatic scenario that could recur in the future if the greenhouse effect persists.
            […]
            Over 2,000 years of monsoon in the Middle East
            According to the researchers, this Mediterranean monsoon dominated the weather in the Middle East for two thousand years. Especially in the summer it rained much more often and more than today. Investigations on flower pollen and Israeli cave deposits confirm the monsoon scenario.

            Unusual Scenario: Monsoon Climate in the Middle East

            Mediterranean Moisture Source for an Early-Holocene Humid Period in the Northern Red Sea

            It’s in my eyes the normal Indian mosoon that, under certain conditions reaches far north west ’til east border of the Mediterranean Sea.

            Further:
            Chapter 2 Relations between climate variability in the Mediterranean region and the tropics: ENSO, South Asian and African monsoons, hurricanes and Saharan dust

          • I’ll give you another link_
            When civilizations collapse – the Tell Leilan project, Syria – Adaptive strategies and altered trajectories at 4,2 – 3,9 ka BP

            High-resolution study of the global 4.2-3.9 ka BP abrupt climate change event is but twenty years old, yet its
            causes and effects have already been defined preliminarily by paleoclimatologists and archaeologists working
            in the deflected tracks of the Mediterranean westerlies and the Indian Summer Monsoon. For example, in Mesopotamia and west Asia the region-wide societal adaptive strategies and altered trajectories are now relatively
            well understood.
            The period of abrupt climate change began with (1) dry-farming regional settlement system abandonment
            and collapse; (2) habitat-tracking to riparian, paludal, and karst spring-fed refugia; and (3) nomadization (subsistence transfer from agriculture to pastoral nomadism). The adaptive social responses at the termination of
            the abrupt climate change included (1) sedentarization and resettlement in dry-farming terrains; (2) political
            state formation; (3) increased and enhanced surplus agro-production; and (4) politico-territorial expansion. Historically and archaeologically, these processes are known as the Early Bronze Age collapse, the Akkadian collapse,
            and the pastoral nomad Amorite infiltration and political ascendance across west Asia

  4. ‘…a glistening disk the size of a dinner plate and the color of rich gravy.”

    You’ll notice they’re using a slab from that cypress, not a core.

    There are many redwood slabs that go back in time ever further in storage in
    Arizona… which seem to be ignored by most dendro/palaeoclimatologists.

    https://ltrr.arizona.edu/giant_sequoia_slab

  5. What? There were climate swings, rapid and from one extreme to another, every 400 years? Wow…CAGW is the Lochnar! Capable of spreading it’s evil throughout time!

  6. As weather patterns today increasingly defy expectations and extreme events become more frequent and severe, this window into past climate variability hints at what may be in store for us in the coming years. “Today is not different than 1,000 or 2,000 years ago,” Nakatsuka says. “We still have the same lifespans and we are still facing large, stressful multi-decadal variation.”

    Notice how the text by the journalist and the quote from the scientist contradict each other.

    • Somebody’s not done a good job of either writing the article, or proof reading it. “This soggy circle is the remnants of a 2,800-3,000-year-old tree” “The results offer unprecedented insight into 2,600 years of Japanese rainfall patterns”

      • So the unprecedented data will give us unprecedented insight into the past but how will the past inform us about unprecedented changes to come, if by definition, these changes are without precedent?

        unprecedented stupidity.

        • Sounds about right pochas94. They did say something about scavenging from temples and other sources.
          Thanks.

  7. The final paragraphs just destroyed any confidence
    “And as our current climate is expected to undergo unprecedented levels of change in the coming decades, the past may hold clues for what we should be preparing for.”
    Having described the varying climate changes over 1,000 or more years, they still had to describe the current changes as “Unprecedented”.

    • If the changes are expected to be “unprecedented”, I suppose the tree ring data must be most useful in telling us what the future will NOT be like.

      Usual breathless media hype, trying to twist whatever science is being reported into fitting the alarmist agenda.

  8. A few thoughts on this article:
    1. The ‘take-home ‘message is ‘“Today is not different than 1,000 or 2,000 years ago,” Nakatsuka says’.
    2. The BBC from whose web site the abridged article is based is well know as strongly supporting the belief in anthropogenic climate change. Hence some contradictions in their article.
    3. Isotopes from Antarctic ice cores have previously been used to estimate long-term temperature changes; most work using tree rings had assumed their growth was correlated with temperature. This research suggests a detailed re-examination of previous long-term climate reconstructions.
    4. If the result of further studies look as if point 1 above (little underlying long-term change) is confirmed there will attempts from the usual suspect to suppress it.

  9. The shift from 350 AD corresponds with the Antique Little Ice Age. The 400 year pattern suggests every fourth centennial solar minimum, which would be a mean 432 years. And that would point to the next solar minimum from the late 2090’s being a major one.

  10. If their findings contradict any of the status quo there will be a swarm of interpretations to correct it’s meaning and devalue their expertise.

  11. But wait, I thought tree rings were thermometers, not rain gauges. Sorry for the sarcasm – life-long habit. Another thought is that for a chaotic system, the past does not predict the future. I would like to see their data and uncertainty bars to see if the cycles are there. Then we can start to guess why. Nothing like a little real data to advance science.

    • I thought they were only using tree rings to date the sample. The rainfall estimates were being done from oxygen isotopes.

  12. So I’m confused. Are tree rings a proxy for rainfall, or temperature ala Mann, or maybe cloudiness, windiness, volcanic dust, cosmic rays, insect predation ? Or are rings sorta random like all the foregoing?

  13. Actually, they don’t tell the future.
    They tell the past, which could give us clues regarding the future.

  14. It’s things like this (500-1000 year weather cycles) that cause me to believe that the 50 year record to determine “climate” is nonsense’.

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