The long memory of the Pacific Ocean

Posted: January 5, 2019 by oldbrew in climate, Natural Variation, Ocean dynamics, research
Tags:

The Great Ocean Conveyor Belt – blue = deep cold and saltier water current, red = shallower and warmer current
[credit: NWS / NOAA]


It’s known, or at least believed, that transit times of some ocean waters can be as long as 1,000 years. The researchers are well aware that this exceeds the time since some well-known warming and cooling periods in the Earth’s past, such as the Medieval Warm Period and Little Ice Age.

Whereas most of the ocean is responding to modern warming, the deep Pacific may be cooling, say researchers.

The ocean has a long memory. When the water in today’s deep Pacific Ocean last saw sunlight, Charlemagne was the Holy Roman Emperor, the Song Dynasty ruled China and Oxford University had just held its very first class.

During that time, between the 9th and 12th centuries, the earth’s climate was generally warmer before the cold of the Little Ice Age settled in around the 16th century.

Now ocean surface temperatures are back on the rise but the question is, do the deepest parts of the ocean know that?

Researchers from the Woods Hole Oceanographic Institution (WHOI) and Harvard University have found that the deep Pacific Ocean lags a few centuries behind in terms of temperature and is still adjusting to the entry into the Little Ice Age.

Whereas most of the ocean is responding to modern warming, the deep Pacific may be cooling.

“These waters are so old and haven’t been near the surface in so long, they still ‘remember’ what was going on hundreds of years ago when Europe experienced some of its coldest winters in history,” said Jake Gebbie, a physical oceanographer at WHOI and lead author of the study published Jan. 4, 2019, in the journal Science.

“Climate varies across all timescales,” adds Peter Huybers, Professor of Earth and Planetary Sciences at Harvard University and co-author of the paper. “Some regional warming and cooling patterns, like the Little Ice Age and the Medieval Warm Period, are well known. Our goal was to develop a model of how the interior properties of the ocean respond to changes in surface climate.”

What that model showed was surprising.

Continued here.

Comments
  1. DB says:

    Hmmm.

    <<>>

    30% is a large number. If the ocean absorbed 30% less heat, this would seem to imply that less heating occurred to produce the surface temps observed, and less heating would imply lower climate sensitivity.

  2. DB says:

    Left out the article excerpt:

    These findings imply that variations in surface climate that predate the onset of modern warming still influence how much the climate is heating up today. Previous estimates of how much heat the Earth had absorbed during the last century assumed an ocean that started out in equilibrium at the beginning of the Industrial Revolution. But Gebbie and Huybers estimate that the deep Pacific cooling trend leads to a downward revision of heat absorbed over the 20th century by about 30%.

    “Part of the heat needed to bring the ocean into equilibrium with an atmosphere having more greenhouse gases was apparently already present in the deep Pacific,” said Huybers.

  3. oldbrew says:

    an atmosphere having more greenhouse gases

    Most so-called greenhouse gas is water vapour. Show us the historical data for that.

  4. ivan says:

    Some regional warming and cooling patterns, like the Little Ice Age and the Medieval Warm Period,

    What do they class as regional or is this an attempt to down play those events which would be typical of anything that doesn’t fit the UN narrative that man is changing the climate.

  5. gymnosperm says:

    Here is a map produced by those folks a while back:

    As you can see, back then they put most of the 2500 meter water in the northern Pacific before the MWP; more like the Viking era.

  6. Gamecock says:

    ‘To test the prediction, Gebbie and Huybers compared the cooling trend found in the model to ocean temperature measurements taken by scientists aboard the HMS Challenger in the 1870s and modern observations from the World Ocean Circulation Experiment of the 1990s.’

    That Challenger must have been one fast ship to get the temperature of 361,000,000 km2 of ocean.

  7. Kip Hansen says:

    Those interested should click through and read the last 1/2 of the Woods Hole press release.

    I was struck by this statement:

    “Previous estimates of how much heat the Earth had absorbed during the last century assumed an ocean that started out in equilibrium at the beginning of the Industrial Revolution.”

    and

    “”Part of the heat needed to bring the ocean into equilibrium with an atmosphere having more greenhouse gases was apparently already present in the deep Pacific,” said Huybers. “These findings increase the impetus for understanding the causes of the Medieval Warm Period and Little Ice Age as a way for better understanding modern warming trends.””

    Yes, yes, yes! The sorry fact is that CliSci does not yet understand the causes of the MWP or the LIA — both which appear to be entirely independent from atmospheric CO2 concentrations. Without that understanding, we are simply guessing at the causes of modern temperature change and hobby-horsing in favor of the CO2 Hypothesis.

    [reply] absolutely

  8. oldbrew says:

    ivan says: January 5, 2019 at 2:54 pm
    Some regional warming and cooling patterns, like the Little Ice Age and the Medieval Warm Period,

    What do they class as regional…

    AFAIK most ‘regions’ seem to check out for LIA and MWP. Large-scale climate phenomena lasting for decades or more on a rotating Earth would surely have a hard job confining themselves to regions 🙂

    The Medieval Warm Period (MWP) was a time of warm climate from about 900 A.D. to 1300 A.D. when global temperatures were apparently somewhat warmer than at present.
    . . .
    An ice core from the eastern Antarctic Peninsula shows warmer temperatures during this period.
    . . .
    Oxygen isotope data from the GISP2 Greenland ice core clearly show a prominent MWP (Fig. 21.8) between 900 and 1300 AD. It was followed by global cooling and the beginning of the Little Ice Age.

    https://www.sciencedirect.com/topics/earth-and-planetary-sciences/medieval-warm-period

  9. wilpretty says:

    This may answer a query I was wondering about today.
    When the last ice age finished, the sea level was 120m higher with a 10C temperature rise. 12m/deg C.
    Eemean interglacial was 2C warmer and sea was 6M higher. 3m/deg C.
    Since 1850 the air temp has increased by 1C but sea level only by 0.3m. 0.3m/deg C

  10. dai davies says:

    There seems to be a quasi-millennial component to solar activity. I don’t have a plot of Nicola Scafetta’s solar model at hand but this southern ocean model was based on it:

    Scafetta, N., 2010, Empirical evidence for a celestial origin of the climate oscillations and its implications, Journal of Atmospheric and Solar-Terrestrial Physics

  11. ivan says:

    Oldbrew, that was my point that the MWP and LIA appears to have been world wide events yet the wording from the report I quoted implies that they were both limited local events to fit in with the UN ‘science’ narrative If they admitted that those events were world wide it would shatter their carefully constructed con that is being perpetrated on the developed nations..

    [reply] yes, they have lost that argument

  12. Salvatore Del Prete says:

    The surface oceanic temperatures are what matters and they will decline in response to very low solar activity.

  13. Stephen Richards says:

    At 1:1000 heat capacity air to water please explain how air heats water. And how much heat does the Pacific lose each day through thunderstorm activity.
    This looks like a paper seeking funding from another source of global warming. Also, if the temperature now is being affected by 1000 yr old weather should we bother with co² tax.

  14. Graeme No.3 says:

    wilpretty:

    You forget that the little Ice Age (and the previous cooler Dark Ages) resulted in sea level drop.
    See Ephasis as a port in Roman times now 8 km. from the sea (but allow for possible tectonic uplift as Turkey is a bit unstable). Even in the UK Roman ports are now unusable except for small boats.
    http://www.ancientportsantiques.com/wp-content/uploads/Documents/PLACES/UK-EUNorth/UK-Cleere2007.pdf
    may be of interest.

  15. oldbrew says:

    if the temperature now is being affected by 1000 yr old weather

    …then the CO2 increases could be partly due to ocean outgassing from MWP warming 🙂

  16. oldmanK says:

    oldbrew says: January 5, 2019 at 5:09 pm tks oldbrew you triggered an idea.

    First: quote oldbrew: ” ice core from the eastern Antarctic Peninsula shows warmer temperatures” during “Medieval Warm Period (MWP) was a time of warm climate from about 900 A.D. to 1300 A.D. when global temperatures were apparently somewhat warmer than at present.” “Oxygen isotope data from the GISP2 Greenland ice core clearly show a prominent MWP (Fig. 21.8) between 900 and 1300 AD”.
    These two polar regions are acting in unison. But is the equatorial region acting in opposite mode?

    Second: A Javier from ‘Climate’ blog indicated that these WP’s coincided to the Eddy cycle peaks. I had been tinkering trying out the fit of the Eddy cycle to the Dodwell ‘snake’ based on the historically measured values of obliquity over the last two millennia. Not a good fit over long time scales but (now I find) the actual points, may fit the Eddy curve better than the curve Dodwell devised.

    The historical data are actual; real. The obliquity curve being followed by science is not – it is only an extrapolation from, also, a curve fitting exercise. Meaning there have been shifts in obliquity that seem to fit the WP’s and the LIA. So are the WP and cooling periods the result of obliquity settling swings?

    (Just to remind: archaeological evidence is clear about earlier abrupt tilt swings. So also indicate large(?) opposing temp swings between polar and equatorial in Holocene).

  17. oldbrew says:

    oldmanK – re. But is the equatorial region acting in opposite mode?

    Assuming the equator hasn’t moved, there’s a sort of natural limit to how high temps there can go. Any excess heat gets sent polewards.

  18. oldmanK says:

    oldbrew: Earth tilt determines the position/latitude of the tropics. Decreasing tilt concentrates more insolation in between tropics at the expense of warming beyond tropics (and brings tropics closer); increasing tilt does the reverse.

    Circulation changes. With low tilt polar caps see much less sunlight and accumulate ice in both mass and spread – a new regimen. We are nearing a peak Eddy and what we see seems to be that.

    Re your question “But is the equatorial region acting in opposite mode?” It is also my question and I don’t have data for the last 1500 yrs. But it was so during the holocene; it was a first corroborating indicator/proxy, also confirming Dodwell.

    Which adds complication since pre 2345bce the mean tilt was different -lower-; again, the abrupt change brought higher temps at polar, but opposite between the tropics (confirmed by the abrupt expansion of the Quelccaya glacier that covered and preserved growing plants ‘overnight’ – Lonnie Thompson research).

    That is, this is dying oscillations about a different and higher mean value.

    [reply] that wasn’t my question – I was quoting you 🙂

  19. hunter says:

    The pernicious nature of propaganda and pc imposed thinking:
    As has been pointed out, the MWP and LIA were “regional” only if “regional” is synonymous with “global”.
    But in a period of history when it is ok for Lewandowsky and gang will call out and threaten scientists who disagree with his opinions, pc censorship is real.

  20. J Martin says:

    @oldmank. Sudden changes in obliquity ? That’s news to me, can you provide a link or point me in the right direction please ?

  21. oldmanK says:

    @ J Martin says: January 6, 2019 at 8:21 pm

    See link: https://tallbloke.wordpress.com/2014/12/24/dodwells-surprising-study-of-the-obliquity-of-the-ecliptic/

    This is the proof: https://melitamegalithic.wordpress.com/2018/03/26/mnajdra-south-calendar-design/ and this is how it was tested: https://plus.google.com/u/0/100013681559928966109/posts/MN1QLxkYnTn

    Since tallbloke’s thread a whole host of other material has appeared that provided corroboration, and some missing dates. All fits, but its one of those things that is difficult – not only to believe – but more so to stomach. Find all at https://melitamegalithic.wordpress.com/

  22. oldmanK says:

    @ J Martin et al: If you are still interested in the matter you can go back into the history of it and the convolutions that resulted in today’s ‘beliefs’. See here: https://malagabay.wordpress.com/2015/04/14/celestial-crystal-balls-and-the-temple-of-amen-ra/

  23. oldbrew says:

    “Some regional warming and cooling patterns, like the Little Ice Age and the Medieval Warm Period, are well known. Our goal was to develop a model of how the interior properties of the ocean respond to changes in surface climate.”

    Which is upside down to how the climate works, i.e. surface is the minor player and ocean the major one.

  24. oldbrew says:

    All quiet on the El Niño front, for now.

    ENSO Wrap-Up
    Current state of the Pacific and Indian oceans
    8 January 2019

    Some recent cooling in the tropical Pacific Ocean

    Tropical Pacific Ocean surface waters have returned to ENSO-neutral temperatures after exceeding El Niño levels in November and early December. The Bureau’s ENSO Outlook remains at El Niño ALERT.

    While waters at and beneath the surface of the tropical Pacific have been warmer than average since mid-2018, atmospheric indicators of ENSO such as cloudiness, trade winds and the Southern Oscillation Index (SOI) have not responded and have mostly remained neutral.

    http://www.bom.gov.au/climate/enso/index.shtml
    – – –
    From: Monthly climate statement for December 2018

    National and international agencies agree that ENSO is currently in an ‘ENSO- neutral’ state. Although Pacific Ocean SSTs have reached El Niño thresholds, most atmospheric indicators remain at ENSO-neutral (neither El Niño nor La Niña) levels. However, the potential still remains for El Niño conditions to develop over summer.

    https://www.longpaddock.qld.gov.au/seasonal-climate-outlook/monthly-climate-statements/

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