Stalagmites as Key Witnesses of the Monsoon

Greenland meltwater stopped Gulf Stream and weakened Indian summer monsoon more than 100,000 years ago

Peer-Reviewed Publication



The ice sheets of Greenland are melting at an alarming rate. This causes large amounts of freshwater to flow into the North Atlantic, thereby slowing the Gulf Stream. Researchers fear that this will have noticeable effects on the climate worldwide. Densely populated tropical areas that depend on monsoon rains for their freshwater supply are particularly at risk. In order to make reliable predictions for future climate change, climate researchers are looking far back into the past. An international team led by Jasper Wassenburg of the Max Planck Institute for Chemistry has now reconstructed how the Indian summer monsoon responded to meltwater pulses into the North Atlantic at the end of the penultimate cold period. In this way, they are able to better understand the global consequences of ongoing anthropogenic climate change.

Around 130,000 years ago, Earth experienced the penultimate change from an ice age to a warm period. During this transition, Greenlandic meltwater had a massive impact on the Gulf Stream. “Two successive episodes of huge freshwater outflows into the North Atlantic first weakened the Gulf Stream and later even caused it to come to a halt completely. This in turn impacted the Indian Monsoon,” explains Mainz geoscientist Jasper Wassenburg. The time interval from 147,000 to 125,000 years ago was therefore ideal to study Monsoon climate response to a weakening of the gulf stream.

Jiangjun dripstone cave:  ancient climate data repository in southwest China

As witnesses to the past, the research group used stalagmites from Jiangjun cave in southwest China, a region sensitive to the Indian summer monsoon. “In continental climates, there is nothing better than stalagmites as a climate archive. That’s because they offer an incomparably high dating precision over many millennia,” emphasizes Hubert Vonhof, who played a key role in the study and heads the Inorganic Gas Isotope Geochemistry research group at the MPIC. The scientists obtained the stalagmite samples from their Chinese colleagues, and collaborators in this study, at Xi’an Jiaotong University, Chinese Academy of Sciences, CAGS.
To analyze and interpret the records, the researchers used a combination of novel proxy data (i.e. indirect indicators of climate events) developed at the MPIC. Thanks to the new methods, the scientists were able for the first time to separately measure and reconstruct temperature variations and changes in the amount and duration of precipitation during the Indian summer monsoon in response to meltwater events.
The temperature measurements of the paleothermometer – which was specially developed for this purpose – revealed a clear picture: The minor meltwater events 139,000 years ago that slowed the Gulf Stream merely shortened the Indian monsoon season in SW China.

Response of monsoon climate to meltwater during the penultimate cold period

More dramatic changes followed from a stronger meltwater pulse that occurred 133,000 years ago. Measurements of microscopic amounts of water trapped in the stalagmites show that the large amounts of meltwater that leaked into the Atlantic 133,000 years ago (and virtually stopped ocean circulation) drastically reduced the intensity of the Indian summer monsoon rains in southwest China. “The study deciphers in unprecedented detail how the monsoon climate responded to the meltwater pulses at that time. We have thus taken a major step forward to better understanding the global consequences of today’s human-induced climate change,” says Vonhof.


Nature Geoscience


DOI: 10.1038/s41561-021-00851-9 


Observational study


Not applicable


Penultimate deglaciation Asian monsoon response to North Atlantic circulation collapse



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November 19, 2021 6:18 pm

Looks like the Danish weather office was not part of the “peer” review process …

Joao Martins
Reply to  John Shewchuk
November 20, 2021 3:45 am

Of course! They would not be independent! Remember that Greenland is a territory of the Kingdom of Denmark! The Danish weather office would be judge in its own cause.

November 19, 2021 6:26 pm

How does that science jibe with this science?

Abolition Man
November 19, 2021 6:47 pm

They had it going well, but then felt compelled to throw in the mandatory, “global consequences of today’s human-induced climate change.”
Maybe someone could locate the point in the geological record where climate change morphed from natural cycles to human-induced; we’ve been asking the usual suspects, but not even the mighty griffter has dared to answer that one! Perhaps the authors should turn their data over to some REAL scientists who are capable of interpretation without ideological or religious constraints!

John Shotsky
Reply to  Abolition Man
November 19, 2021 7:22 pm

More importantly, it should be understood that the ‘normal’ status of world climate is ice age, not interstadial. Ninety percent of the time we are in glacials. Ten percent we are in interglacials. We are nearing the end of our current interglacial. Why are they called interglacials? Because those are the hiccups between glacials. Don’t look now, but glacial is in our future, not a global warming event. That’s over. We (collectively) are worrying about the wrong thing. We are not preparing nuclear power to deal with a return to glacial times, with attendant crop losses and land loss as ice takes over. Only 12000 years ago, there was a MILE of ice where New York City now sits. THAT WILL HAPPEN AGAIN. Think about what that means. How much money should we spend on CO2, again?

Reply to  John Shotsky
November 19, 2021 7:53 pm

Yes, if one thing this idiocy has revealed, it is that we almost certainly can’t put enough of the magic gas into the atmosphere to stave off the decline into the abyss of the glacial phase. I’m not even sure nuclear can do it, except locally. I think we probably are technologically advanced enough though to increase insolation globally without frying people (I’m thinking large space-based reflectors maybe)?

Probably some guillotines too, to make sure the current f-wit climate liars can’t slime in on the solution and wreck that for human prosperity, as they are doing now.

Reply to  John Shotsky
November 20, 2021 12:21 am

Then again, about 75% of the last 550 million years has been essentially ice free, except perhaps at extreme altitudes.

Moderately Cross of East Anglia
Reply to  AndyHce
November 20, 2021 1:06 am

I’m so glad that someone mentioned that – the current ice age is not the “norm”. Nor am I convinced ( but I’m willing to listen to the possible reasons) that with as deeply complex and chaotic a system as the Earth’s climate variation that a similar set of events 100,000 or whatever number of years ago would necessarily have the same results today or in the future.
A little more uncertainty in many of the current climate assertions wouldn’t go amiss all round.
If we really were significantly warming the climate and risking preventing the ice coming back – a prospect that seems to terrify the idiotic BBC – why would that be a bad thing when we know the Earth has been much warmer for most of the last 500 million years?

Julian Flood
Reply to  Moderately Cross of East Anglia
November 20, 2021 9:08 am

MC of EA, I’m currently sitting in the Eel’s Foot in Eastbridge, right next to Sizewell. This whole area, the nicest part of the East Anglian coastline is about to be ruined by the construction of Sizewell C. Moderately Cross is not enough. I’m bloody furious.

If the worst reactor design they could have chosen – French of course – were not bad enough, the damn thing will not come on stream until the climate hysteria has been seen as scientific nonsense.

Damn Johnson and his ignorant leman, damn whichever idiot is Secretary of State for Energy and Climate Change, damn the corrupt ‘science’ that has brought us to this pass.

Sod the lot of them. May the bluebird of happiness poop on their breakfast muffins until the next millennium.

Don’t get me started on bloody Sunnica.

Clyde Spencer
Reply to  Julian Flood
November 20, 2021 10:28 am

Go easy on the politicians! After all, if they didn’t go into politics, most of them would have to go on the dole, since they really don’t have any marketable skills beyond those also held by actors and snake oil salesmen.

Ron Long
Reply to  AndyHce
November 20, 2021 2:07 am

Sort of right, Andy, but not totally correct perspective. The last “Snowball Earth” event ended around 635 million years ago, so, yea, we had some good (warm) times in the last 550 million years. However, the last 5 million years has seen us 90% of the time in glacial status, with the interglacial time shortening. We are in an Ice Age. Can CO2 save us? Hard to imagine so.

Joseph Zorzin
Reply to  Ron Long
November 20, 2021 4:11 am

“Can CO2 save us?”

When it really starts getting cold and the glaciers advance rapidly, the greens will be insisting that we build new coal power plants! Folk singers will write new songs about the glories of coal.

Julian Flood
Reply to  Ron Long
November 20, 2021 9:10 am

I think I know how to replicate the PETM. Would that do?


Reply to  Ron Long
November 20, 2021 9:32 am

I’m not convinced that these snow ball earth events actually happened,
The evidence that I’ve heard to support these claims is the existence of glaciers very close to the equator.
The evidence that the land was near the equator came from measuring the angle of the magnetic field found in the rocks. If the magnetic fields were near vertical that showed the rocks were formed near the magnetic poles, if the magnetic fields were near horizontal, then they formed in the region halfway between the two magnetic poles. In today’s world, that would put those sites near the equator.

My problem with this assumption is that we now know that the magnetic poles move, quite a lot. How do we know that at the time these rocks were being laid down, the magnetic poles were near the rotational axis? What if the magnetic pole was 30 or 40 degrees away from the rotational axis, that would move the location where these rocks were being formed to a place 30 to 40 degrees away from the equator.

Beyond that, how do we know the altitude of these rocks, at the time they were being scoured by glaciers. Even today, glaciers exist near the equator, so long as the altitude is sufficient.

Dave Fair
Reply to  Ron Long
November 20, 2021 9:51 am

All of the past cooling and warming events are interesting, but all anybody really wants to know is will it rain tomorrow. Destroying Western societies, economies, and energy systems over UN IPCC CliSciFi computer games is anti-survival.

Reply to  Ron Long
November 22, 2021 4:41 pm

The current ice age, considered as when temperatures fall and ice sheets form, outside of Antarctica and Greenland, is about half of 5 million years. Calling it on Antarctica’s ice sheet existence puts the time at 30 to 35 million years.

Abolition Man
Reply to  AndyHce
November 20, 2021 4:43 am

What you say is true, but until we acquire a better understanding of what ACTUALLY controls Earth’s climate; it is whistling past the graveyard to think that the last 50 million years of falling temperatures is over! Especially if we look back to the trend since the Middle Miocene Thermal Maximum, 15Mya! Whether it is due to tectonic, orogenic, or solar radiative changes; the recent cooling of our planet is quite worrisome!
The refusal to even discuss the dramatic cooling over the geologic past, and the evidence that previous interglacials were warmer than the Holocene is evidence of a close mindedness normally associated with extreme religious fervor or regular drug use. That is why I will continue to prick the griffter and our other trolls for being medicated; they display an unwillingness to discuss the REAL science that often seems like an hypnotic or trance state!
On the plus side, the Karoo Ice Age only lasted for 100 million years; so we can look for the warmth to return in just 85 million more! Maybe!

Ron Long
Reply to  Abolition Man
November 20, 2021 6:00 am


John Tillman
Reply to  Abolition Man
November 20, 2021 9:09 am

The Carboniferous-Permian ice age lasted about 90 million years, from c. 350 to 240 Ma. High southern latitudes sported an ice sheet even before this time.

While Earth started cooling in the Eocene Epoch, the present Cenozoic ice age didn’t begin until the Oligocene, c. 34 Ma, when deep oceanic channels opened between Antarctica and South America and Australia.

Then Pleistocene ice sheets formed in the Northern Hemisphere after the Isthmus of Panama formed, c. 3 Ma. Greenland probably already had a partial ice cap even in the Pliocene.

Reply to  AndyHce
November 20, 2021 8:50 am

That is irrelevant. When there are trends within trends within trends, the most recent trends are more important, and that is short interglacials within larger glacials.

Or I could correct you in the other extreme. Only 5 of the last 13 billion years has had any Sol or Earth at all. The trend is obviously No Sol+Earth, and the last 5 billion years is an insignificant deviation.

Rich Davis
Reply to  John Shotsky
November 20, 2021 7:46 am

Well, certainly a mile of ice over New York City is a worthy goal, but that might have negative consequences for good places, so I’m not sure we can support your plan, John 😜

Reply to  Abolition Man
November 19, 2021 9:47 pm

A professor remarked to me, that that was how you got funding – just toss in a reference to global warming in the summary, and let the rest of the paper tell the truth…

Reply to  Leo Smith
November 20, 2021 4:52 am

The problem with that is a single lie negates the entire thing. Credibility, at this point the scientific community has pissed theirs’ away.

Reply to  Leo Smith
November 20, 2021 9:47 am

The biggest problem is that most of the usual idiots only check the summary when deciding whether a paper supports the “consensus”, not the paper as a whole.

Reply to  Abolition Man
November 20, 2021 5:30 am

Yep, that one phrase, that silly need to make excuses, stopped me at that spot.

Reply to  Abolition Man
November 20, 2021 8:45 am

The very first sentence was my clue to stop paying attention: “The ice sheets of Greenland are melting at an alarming rate.”

Clyde Spencer
Reply to  Abolition Man
November 20, 2021 10:23 am

griff is pretty much a one-way conduit. He regurgitates things from sources like the BBC and ‘Gruniad,’ and when challenged, either ignores the questions, or does another dump. The second one is sometimes even in context. He/she/it is not known for engaging in logical dialog.

November 19, 2021 8:19 pm

They’ve got a stalagmite from one cave in Southwest China and they find causation for:

During this transition, Greenlandic meltwater had a massive impact on the Gulf Stream. “Two successive episodes of huge freshwater outflows into the North Atlantic first weakened the Gulf Stream and later even caused it to come to a halt completely. This in turn impacted the Indian Monsoon,” explains Mainz geoscientist Jasper Wassenburg.”

They didn’t verify with stalagmites from nay cave.
They did not core the Atlantic seeking sediment cores.
They did not even verify the India Monsoon stopped during that period. For all we know, their selected cave had a landslide that blocked water inflow.

Instead, they leap to multiple conclusions including that Greenland’s meltwater stopped the Gulf Stream.

What? Did the meltwater flow down the East coast and into the Gulf of Mexico to disrupt the Gulf warming?

By the time the Gulf Stream has passed the Bahamas, it isn’t stopping for a cold surface layer.

Reply to  ATheoK
November 20, 2021 4:42 am
Clyde Spencer
Reply to  ATheoK
November 20, 2021 10:35 am

There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.

Mark Twain

Mike Dubrasich
November 19, 2021 8:42 pm

Many questions;

1. Why this one cave when there are hundreds of other caves much closer to the Indian Ocean and the monsoon belt?

2. Why study the Eemian when there were huge meltwater pulses more recently after the last LGM ~20 kya?

3. The continental ice sheets have already pulsed. Nobody expects another such for 100,000 years or more during the next interglacial after the coming stadial. What does any of that have to do with the present?

4. Researchers fear… Why? Is raging paranoia a requisite for The Science as well as desperate journalistas aching for a smidgen of relevancy? I’m not afraid of non-existent meltwater pulses or unicorns. What’s their problem?

Rich Davis
Reply to  Mike Dubrasich
November 20, 2021 8:01 am

I’m not afraid of non-existent meltwater pulses or unicorns. What’s their problem?

Meltwater pulses, nah! But unicorns? When you’ve seen one of them charging toward you with that fearsome spear pointing right at your heart like a Wisconsin prosecutor pointing an AR-15 at a jury? Now that’s scary right there, MD.

Richard Page
Reply to  Mike Dubrasich
November 20, 2021 7:00 pm

There just seemed to be far too many assumptions and assumptions built on other assumptions. So this stalagmite, which may be calibrated correctly or not, shows a different pattern of layers and water in the flowstone and the authors immediately jump to their conclusions without any other proof than ‘because’. Needs more work, lots more work.

Wim Röst
November 19, 2021 8:47 pm

From the post: ““Two successive episodes of huge freshwater outflows into the North Atlantic first weakened the Gulf Stream and later even caused it to come to a halt completely.”

WR: Famous oceanographer Carl Wunsch in Nature about the impossibility ‘to stop ocean circulation’ in the North Atlantic:

“European readers should be reassured that the Gulf Stream’s existence is a consequence of the large-scale wind system over the North Atlantic Ocean, and of the nature of fluid motion on a rotating planet. The only way to produce an ocean circulation without a Gulf Stream is either to turn off the wind system, or to stop the Earth’s rotation, or both.

Real questions exist about conceivable changes in the ocean circulation and its climate consequences. However, such discussions are not helped by hyperbole and alarmism. The occurrence of a climate state without the Gulf Stream any time soon — within tens of millions of years — has a probability of little more than zero.”

(bold added, WR)

Gulf Stream safe if wind blows and Earth turns

Jeff Alberts
Reply to  Wim Röst
November 19, 2021 9:18 pm

The only way to produce an ocean circulation without a Gulf Stream is either to turn off the wind system, or to stop the Earth’s rotation, or both.”

Or a change in continental configuration…

Pamela Matlack-Klein
Reply to  Jeff Alberts
November 20, 2021 1:56 am

I was thinking the same thing, but with North America continuing to move westward we are a very long time from a new continental configuration that would affect the Gulf Stream. It would be fun to have a time machine for quick trips to the far distant future to see how planetary geography changes over millions of years.

Wim Röst
Reply to  Jeff Alberts
November 20, 2021 3:46 am

Jeff Alberts: “Or a change in continental configuration…”

WR: Correct. What if the Atlantic was not positioned North-South, but East-West around the equator?

But the most interesting question for me is (and perhaps somebody knows):
“What would the atmospheric and oceanic circulation be, in case there would not be any Land at all and the ocean would have had an equal depth everywhere of 3,6 kilometers (which is present’s average)?”. So, for an ‘All Ocean World’.

Note: shortly after the formation of the oceans there was hardly any Land if any. Surface temperatures probably were not influenced by continents nor by topography (mountain ridges).

Reply to  Wim Röst
November 20, 2021 8:04 am

Europa, Jupiter’s moon.

“an ‘All Ocean World’.” (frozen though)

just saying… stating a fact there.


November 19, 2021 8:57 pm

What I get from the abstract is that both the most recent meltwater pulse and the one prior affected the Indian monsoon. I’m good with that.

What I know is that there’s no comparison to the amount of ice locked up in a glacial and the amount locked up in glaciers today.

How could we get a meltwater pulse now that’s comparable to the last two?

It wasn’t warm enough to rapidly melt Greenland and Antarctica during the last three optimums of the Holocene. What evidence is there that there is an optimum on the horizon that’s greater than the Holocene optimum? And even if such evidence is shown, is there enough ice left to halt the Gulf Stream.

I think the researchers are a little too far out over their skis on this one. I’m not sure there’s enough ice and I’m certainly not seeing any indication that temperatures will rise fast enough for a rapid pulse of meltwater from the ice remaining on Greenland and Antarctica.

Now if they were to predict that at the end of the next glaciation there would be a huge meltwater pulse that would seriously slow or halt the Gulf Stream and affect the Indian monsoon, that’s testable and I think they might come out a winner on that one.

Pamela Matlack-Klein
Reply to  H.R.
November 20, 2021 2:04 am

Regardless of how much water remains locked up in the poles, Greenland, and various glaciers around the globe, what is the likelihood that the next warming would be as warm or warmer than the Holocene? Each subsequent warm has been a bit cooler after all. The pertinent question here is what is causing this decrease in warmth over the millennia? This is research I would like to see funded.

Abolition Man
Reply to  Pamela Matlack-Klein
November 20, 2021 4:53 am

It would nice to see some real science funded, but the Lords of Climastrology have declared that some time in the last century the Evil Gas of Doom acquired control over ALL natural climate processes! This makes it imperative to spend vast sums of treasure on figuring out the many ways we are F’ed!
It’s kind of like a college course that explores the ramifications of Sauron winning control of the Ring; something that I could have wasted countless hours on if my stoner friends had been more literary!

Rich Davis
Reply to  H.R.
November 20, 2021 8:20 am

What we see here is called “putting down a marker”. It’s good evidence that the scam runners are worried that not only are their scary models running way too hot, but also that ocean and solar cycles are turning toward cooling phases.

If we see significant cooling, they will point to this rubbish to explain it as being actually caused by global warming, rather than by natural factors. So it will become even more urgent that we eliminate fossil fuel use and increase the subsidies on the useless unreliables.

Kind of like when covid cases spike highest in areas with the highest vaccination rates, it’s urgent to force everyone to get vaccinated or lose their jobs.

Dave Fair
Reply to  H.R.
November 20, 2021 10:00 am

But will it rain tomorrow?

Reply to  Dave Fair
November 20, 2021 11:59 am

50% chance of showers. 😜

Dave Fair
Reply to  H.R.
November 20, 2021 1:16 pm

All odds are 50/50; either something happens or it doesn’t.

Reply to  Dave Fair
November 20, 2021 8:39 pm

We had a 3% chance of precipitation today. We got snow, about one 10,000th of an inch, but snow none the less.

November 20, 2021 1:15 am

This original post (O.P.) is not breaking news, nor is stalagmite analysis. The regional intertropical convergence zone (ICTZ), where wind and moisture converge, migrates in the “summer” northward toward India and it’s pressure cell(s) come up against the Tibetan plateau’s pressure cells; essentially provoking the summer monsoon [in a dynamic involving other water body dynamics, among other things].

When the regional ICTZ seasonally shifts back south the summer monsoon rains end and dry weather resumes [this regional ICTZ longitudinal band is found around 25*South in January]. The O.P. uses comparative levels of stalagmite delta-18 isotope O (oxygen) because northern moisture is more enriched in that isotope than moisture from the more southern Indian Ocean (ie: monsoon moisture).

For example there was a meltwater blast of ~9.2 thousand years ago that was much greater (~5.1 Sverdrups) than another one around 8.2 thousand years ago (~0.27 Sv; where 1 sverdrups = 1×10^6 cubic meters/second). Evidence of these events show up in Greenland ice cores.

In simple terms what the huge meltwater pulse did was lead to greater snow cover over Eurasia. The resultant greater albedo meant the Tibetan plateau warmed less come “summer” and that resulted in less of a pressure gradient in regards to the northward moving ICTZ, and also less moisture convection. This is how the O.P.’s stalagmites in SW China got less Indian summer monsoon water.

Abolition Man
Reply to  gringojay
November 20, 2021 5:00 am

While you get bonus points for the use of “Sverdrup” in a sentence; there is a penalty for mis-acronyming the ITCZ! Sorry, but it was an itch I just had to scratch!

Reply to  Abolition Man
November 20, 2021 9:16 am

Can I “blame it on The Bossa Nova” …?

November 20, 2021 2:47 am

In order to make reliable predictions for future climate change, climate researchers are looking far back into the past.

How many times do we have to tell you, with a chaotic system, there are NO reliable predictions possible, for the future, at least.

Rich Davis
Reply to  Disputin
November 20, 2021 8:30 am

Yes, some pinstriped philosopher once said that predictions can be difficult, especially when we’re talking about the future.

But I’d submit that the future is certain, only the past is unpredictable. We already know that every year temperatures will rise. What we don’t know is how much the 1920s and 1930s will cool, or for that matter, the medieval, Roman, Minoan, or Egyptian formerly-warm periods.

Joao Martins
November 20, 2021 3:50 am

This article seems to be more science-fiction than science.

Have any of the authors a degree in creative writing?

Joseph Zorzin
November 20, 2021 4:09 am

“novel proxy data”
I don’t trust any proxy data. How can it be proven? So at best, it’s only a rough approximation, especially tree ring data.

November 20, 2021 4:36 am

Nothing makes me accept a study faster than starting it out like this, “The ice sheets of Greenland are melting at an alarming rate.”. Perhaps a pic of AlGore:TheGoreacle spewing his fiery breath on the glaciers would make it more compellingly believable. 😉

Mr Julian Forbes-Laird
November 20, 2021 4:55 am

“The ice sheets of Greenland are melting at an alarming rate”

I stopped reading at this point.

November 20, 2021 5:35 am

Over here on this continent, that was the Sangamon warm period (names may have changed in the last few years). There are plenty of cave systems on this continent that have the same indicators. Maybe these folks could draw a comparison graph.

Did they have to put in that last bit about man-made globull climactic tweaking? It just gets silly after a while.

D. J. Hawkins
November 20, 2021 8:48 am

I think the key thing to consider, granting their thesis for the moment, is “What is the magnitude of any potential melt-water pulse?” there was a lot more ice available to melt at those times.

Dave Fair
November 20, 2021 9:35 am

Since both the 139,000 and 133,000 y/o postulated meltwater pulses were part of the naturally varying climate, why assume that Man will cause any putative changes to the climate? Especially since the UN IPCC CliSciFi climate models producing high ECSs have been proven to be junk. Even the high priest of UN IPCC CliSciFi modelers, Gavin Schmidt, says so.

November 20, 2021 10:19 am

Researchers fear…

It seems that horror stories are now required to be the topics of recently published papers. I’m sure the peer reviewers sat anxiously on the edges of their seats as they were peer reviewing this article when it told them how to feel when reading it.

Kevin McNeill
November 20, 2021 3:23 pm

As I understand it ” penultimate” means next to last. Are we to infer from that usage in this paper that the next ice age will be the last. How can they possibly know that? That little error alone makes me think that the entire paper is an exercise in magical thinking.

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