Think zebras not just horses

[transmitterdan]

Some years ago I read a thread (since closed) that brought up the concept of "abrupt climate change". Apparently there was/is a whole branch of research on the topic.

http://www.cruisersforum.com/forums/...tml#post533361

The researchers found that there was a rapid change in climate and concluded that such a rapid change proved that the climate reached a "tipping point" and therefore it could once again.

Now there is research that explains what they saw and it has nothing to do with a climate tipping point. Apparently a huge impact event happened and it took the earth a millennia to recover. 10% of the earth's land surface burned off. That's an astounding discovery.

https://phys.org/news/2018-02-ice-ag...ed-larger.html

[jimbunyard]

Originally Posted by transmitterdan

Some years ago I read a thread (since closed) that brought up the concept of "abrupt climate change". Apparently there was/is a whole branch of research on the topic.

www.cruisersforum.com/forums/f80/mass-plankton-die-off-44384-30.html#post533361

The researchers found that there was a rapid change in climate and concluded that such a rapid change proved that the climate reached a "tipping point" and therefore it could once again.

Now there is research that explains what they saw and it has nothing to do with a climate tipping point. Apparently a huge impact event happened and it took the earth a millennia to recover. 10% of the earth's land surface burned off. That's an astounding discovery.

https://phys.org/news/2018-02-ice-ag...ed-larger.html

Interesting that of the three 'studies' linked to in the original post in the 'mass die-off' thread

https://cbsfwbam.wordpress.com/pages...tentId=6547648

http://www.postcarbon.org/blog-post/...the-food-chain

http://www.nature.com/news/2010/1007....2010.379.html

only the last one is is still up for inspection, and upon inspection it proves that it says nothing like

"...there was a rapid change in climate and concluded that such a rapid change proved that the climate reached a "tipping point" and therefore it could once again."

What it does say is that phytoplanktonic biomass has declined about 40% from the 1950s to the date of the study (2010), and that it appears that the root cause is the increasing temperature of the world's oceans.


What this article

https://phys.org/news/2018-02-ice-ag...ed-larger.html

has to do with the 'mass die-off' of plankton I have no idea. Aside from the debatable title of the article (the hypothetical 'global firestorm' resulting from the KT impact would seem to out-size the hypothetical '10 percent of the Earth's land surface' by about 90 percent...), since the cooler water resulting from the global dimming from the aerosols, not to mention the fertilization of all that ash falling and washing into the ocean, would seem to lead to better conditions for plankton. But then they're phyto-plankton so maybe it's a wash...

The comet-fragment impact hypothesis 12800 years ago seems a good candidate for the cause, or main cause, of the Younger Dryas (which is more what the article is actually about), but likely the sexier story is what it means as/for the cause(s) of the extinction of the large North American mammals of the time. Unfortunately, of the two competing guesses (humans or impact), both are somewhat invalidated as sole causes because, according to the most recent findings the extinctions started about 16000 years ago, well before either humans or comet fragments arrived...

[transmitterdan]

The post copies the now unavailable text verbatim. The Greenland data supposedly provided long sought proof that abrupt climate change is in the geologic record and therefore is possible today. The implication being that CO2 increase could trigger a similar abrupt change in climate. But now, after a world wide study, we find that there was no abrupt climate change. There was a massive impact with a comet that burned off 10% of the earths land mass. That in turn triggered a huge change in earth’s climate that took a millennia to recover. So what the Greenland data actually suggests is the opposite of the original proposition. Earth’s climate tends to find an equilibrium even when slammed off balance by a comet impact sufficient to cause a 1,000 year ice age.

[john61ct]

There are other "abrupt" changes coming.

Sea level won't rise slowly but in big surges.

Anything over 6" at a time will be catastrophic to modern humanity.

Much larger than that is very likely.

Hopefully after we're all dead, which attitude of course is the fundamental cause of the problem...

Ancestor worship will go out of fashion pretty quickly when the time comes.

[jimbunyard]

Originally Posted by transmitterdan

The post copies the now unavailable text verbatim. The Greenland data supposedly provided long sought proof that abrupt climate change is in the geologic record and therefore is possible today. The implication being that CO2 increase could trigger a similar abrupt change in climate. But now, after a world wide study, we find that there was no abrupt climate change. There was a massive impact with a comet that burned off 10% of the earths land mass. That in turn triggered a huge change in earth’s climate that took a millennia to recover. So what the Greenland data actually suggests is the opposite of the original proposition. Earth’s climate tends to find an equilibrium even when slammed off balance by a comet impact sufficient to cause a 1,000 year ice age.

Well then, we'll have to take your word about the verbatim-ness of the quote, but it is conveniently beside the point, for a variety of reasons.

Far from 'disproving' existence of tipping points, the occurrence of the Younger Dryas by impact verifies that such things can and do happen.

That the earth is resilient and can adapt to environmental change is unquestionable, as it has in the past and will continue to do so.

The cometary fragment impacts were a large, but still regional event, and did not result in a '1000 year ice age', but rather slowed the warming that was already underway from the Earth coming into the 'warm' period of the Milankovich cycle. From your article

"Ocean currents shifted, setting the climate into a colder, almost "ice age" (their quotes) state that lasted an additional thousand years."


As it stands now, business-as-usual is shaping up to look like something between the Permian and KT mass extinctions, that is if you believe the scientists and their data, which from your quoting of the phys.org article it seems you do (though it does also seem that you're cherry-picking certain information to support your personal beliefs...)

If you're comfortable with a from 2-10 million year recovery period, where all large (over 20 kg) animals are initially absent, then by all means continue on your current path... After all the KT impact extinction gave the Earth humans, there's no telling what the Anthropocene extinction will give the Earth...

This is the 'equilibrium' that you, apparently, so blithefully refer...

[transmitterdan]

My only point was that some "scientists" had seen a set of facts and interpreted them to support their theory. But in this case the facts do not support the tipping point argument. The climate did not rapidly shift 12,800 years ago due to any terrestrial process. So far the examples of abrupt climate change in the geologic record are all due to extraterrestrial events (i.e. impact events). If I am wrong please show an example from the past.

[jimbunyard]

Originally Posted by transmitterdan

My only point was that some "scientists" had seen a set of facts and interpreted them to support their theory. But in this case the facts do not support the tipping point argument. The climate did not rapidly shift 12,800 years ago due to any terrestrial process. So far the examples of abrupt climate change in the geologic record are all due to extraterrestrial events (i.e. impact events). If I am wrong please show an example from the past.

That the climate is subject to abrupt changes due to biospheric inputs is an established fact; there is no argument in the scientific community about it.

An excerpt from the abstract ( http://www.journals.uchicago.edu/doi/10.1086/695703 ) of the paper that the article you referenced was based on supports this;


"The ice record is consistent with YDB impact theory that extensive impact-related biomass burning triggered the abrupt onset of an impact winter, which led, through climatic feedbacks, to the anomalous YD climate episode."


Furthermore, the sequential draining of the post-glacial Lake Agassiz probably had at least as large, and likely larger effect on the Younger Dryas than the hypothesized (though after ice core analysis it carries more weight) 'cometary fragment impacts'.

As for "...the examples of abrupt climate change in the geologic record are all due to extraterrestrial events..." the examples are too numerous to list (and far outnumber those of 'ET events').

Instead, here is a link to a paper by the National Academy of Sciences on the subject. It's perusal might persuade you as to the complexity of said subject and the hazards of forming opinions based on a very incomplete news blurb...

https://www.nap.edu/read/10136/chapter/4#72

[senormechanico]

Here we go again. Start the countdown clock to closing.

[JPA Cate]

Originally Posted by senormechanico

Here we go again. Start the countdown clock to closing.

Whether or not the thread stays open will depend upon the posters' behavior in the thread. The rule is that off topic (from cruising)
discussions are permitted as long as there is not disruptive behavior.
So, if the posts are respectful and data oriented, all will be well, and the thread will stay open. If they fail the "be nice" rule (in red in the Community Rules), or the vulgar, coarse, or sarcastic prohibitions, the thread will be closed.

[SailOar]

Originally Posted by jimbunyard

....Unfortunately, of the two competing guesses (humans or impact), both are somewhat invalidated as sole causes because, according to the most recent findings the extinctions started about 16000 years ago, well before either humans or comet fragments arrived...

Maybe not germane to the main topic of this thread, but recent evidence suggests that humans may have arrived in North America well before 16,000BP.

Genetics Rewrites the History of Early America—And, Maybe, the Field of Archaeology | Smithsonian

It's Official: The First Americans Weren't The Clovis People After All | IFLScience

Incredible Discovery Reveals Human Activity In The Americas 130,000 Years Ago | IFLScience

[transmitterdan]

Originally Posted by jimbunyard

Instead, here is a link to a paper by the National Academy of Sciences on the subject. It's perusal might persuade you as to the complexity of said subject and the hazards of forming opinions based on a very incomplete news blurb...

https://www.nap.edu/read/10136/chapter/4#72

Thank you for the link. I don’t have an opinion. I am looking for facts. The most studied recent abrupt climate event (Younger Dryas) has now been said to have occurred as a result of multiple comet fragment impacts. As I understand that is a recent finding which prompted this thread. In the past the YD climate shift has been used to show that abrupt climate change can occur organically with small unknown forcings. But now we know that did not happen in the case of YD. A major ET event caused the abrupt change.

I am not saying abrupt change cannot happen. I am asking for non ET examples. Or perhaps stated another way as a result of non cataclysmic events. I have not been able to find any example of a rapid shift in climate that was caused by anything other than huge and widespread devastation such as asteroid, comet or volcanic eruption.

Is there any example in the research of rapid change in climate caused by something else besides a devastating event?

[zeehag]

whoopeeee... we all gonna die.... chikkin little on a run.
wait til poles flip and life changes ... will be well after our tenure on this planet unless you are celt or whatever and have many reincarnations hahahahaha

[jimbunyard]

Originally Posted by SailOar

Maybe not germane to the main topic of this thread, but recent evidence suggests that humans may have arrived in North America well before 16,000BP.

Genetics Rewrites the History of Early America—And, Maybe, the Field of Archaeology | Smithsonian

It's Official: The First Americans Weren't The Clovis People After All | IFLScience

Incredible Discovery Reveals Human Activity In The Americas 130,000 Years Ago | IFLScience

I suppose it's never too early for a little thread drift...

That individuals or bands of humans or hominims had reached the Americas before 14000 BP is highly likely (maybe even to be expected, given that over the at least last half a million years sea level has fluctuated over 200 ft), there is evidence that they arrived from Europe and Asia, and even some (though more contested) that they arrived in South America directly from Africa.

That doesn't mean they flourished, or that they were ever there in numbers enough to have an effect on large mammal populations.

Additionally, genetic studies have been done on native American peoples that show that their ancestry, without going into too many details, is from a single wave of 'Eurasian migrants with Australasian ancestry' via the Berengia land bridge (or possibly coastal boating, who knows?)

As far as I know there has been no genetic evidence found for either direct European or African heritage for any modern native American people. That of course could change tomorrow...

[transmitterdan]

More drift...another recent finding shows that the Maya civilization of a millennia ago had much larger populations than previously thought. And their urban areas were on a par with other civilizations such as the Greek. Science is like life, the more we learn the more we find our previous knowledge was wrong.

Mayan civilization was much vaster than known, thousands of newly discovered structures reveal

https://apple.news/As4twtqM5Rkiv9kCxIB-usw

[StuM]

Originally Posted by jimbunyard

Far from 'disproving' existence of tipping points, the occurrence of the Younger Dryas by impact verifies that such things can and do happen.

On the coutrary, the Younger Dryas confirms that even large perturbations do not result in a "tipping point" and a new regime. Temperatures recovered to the pre YD end-of-glacial trend quite rapidly.