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Global Warming / Climate Changes Pt. 21

Re: Global Warming / Climate Changes Pt. 21

Unread postby Keith_McClary » Sat 01 Jun 2019, 22:47:51

dissident wrote:Being a self-organized critical system, ice sheets can exhibit nonlinear responses to heating. Instead of ablating over centuries, they experience surges in flow and catastrophic ice loss.


Is the Weertman model not a good way of thinking about ice sheets?
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Re: Global Warming / Climate Changes Pt. 21

Unread postby Plantagenet » Sat 01 Jun 2019, 23:33:50

The Weertman model for glaciers and ice sheets is now over 40 years old. It works reasonably well for describing the behavior of ice sheets where the basal ice is sitting directly on solid rock, and the motion of the ice is controlled by the physics of the ice.

Over the last 40 years our knowledge of glaciers has expanded immensely, and in particular two additional types of glacier behavior have been described. First, in addition to the ice and the rock, we now know there is a great deal of water in most glaciers. This is a very important addition to make, because we now know in many cases there is so much water that the hydrostatic pressure from the water is almost supporting the entire load of the ice, i.e. if the "water table" in the glacier is within about 90% of the surface of the glacier, then the denser water hydrostatically supports the ice. This dramatically changes our understanding of how glaciers move. One practical implication of this is "surging glaciers" i.e. glaciers with non-linear behavior that sometimes accelerate by orders of magnitude. Here in Alaska some friends of mine drilled into a surging glacier to study the water pressure. They found that the velocity of the surging glacier was directly controlled by the water pressure, i.e. more water in the glacier means less friction at the base because the weight of the ice is supporting, allowing to move much faster, i.e. surge.

The second type of new glacier behavior is the realization that most glaciers don't sit on hard bedrock. They sit on fractured rock, clay, and silt created by erosion at the base of the glacier. This sediment layer can itself deform and shear, so the motion of some glaciers is controlled by the shear strength of the underlying sediment, rather then just the physics of ice. AND, the basal sediment or till layer becomes a very slippery clay when you add water under pressure, so the glacier can more easily slide right along on top of the deforming basalt sediment layer.

Thee implications of these new glacier models is very large in the context of global warming, which has a tendency to create huge amounts of glacier meltwater. For instance, in most of Greenland you now see now huge rivers forming on the surface of the ice sheet which reach the base of the glacier, and make it flow faster. These rivers didn't form back in the early and mid-20th century, but they are everywhere now.

Image
Increased warming means huge rivers now regularly form at the surface of the Greenland Ice Sheet. These rivers plunge to the base of the glacier through huge moulins, lubricating the base and accelerating the flow of the ice sheet.

Cheers!
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Re: Global Warming / Climate Changes Pt. 21

Unread postby dohboi » Sun 02 Jun 2019, 11:34:33

Thanks, Plant. Very informative!
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Re: Global Warming / Climate Changes Pt. 21

Unread postby dohboi » Tue 04 Jun 2019, 09:35:13

Climate change could pose 'existential threat' by 2050

https://www.cnn.com/2019/06/04/health/c ... index.html

When you factor in scientific reticence, I think we can translate the headline to: GW will kill all or most of us within the next very few decades.

"A doomsday future is not inevitable," he notes. "But without immediate drastic action our prospects are poor."


And does anyone see any possibility of 'immediate, drastic action' from the US, England, Australia, Brazil, Russia...

It's pretty clear that doomsday is, practically speaking, in fact inevitable.

Have a good day.
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Re: Global Warming / Climate Changes Pt. 21

Unread postby Ibon » Tue 04 Jun 2019, 11:46:00

dohboi wrote:
And does anyone see any possibility of 'immediate, drastic action' from the US, England, Australia, Brazil, Russia...

It's pretty clear that doomsday is, practically speaking, in fact inevitable.

Have a good day.


The answer to your question. Just consider how many times you posted a similar dire prognosis and posed the exact same question during the last 10 years.

Now consider that in exactly 10 years from today you will most likely still be here with the same predictions asking the same question.

As we decline into dire consequences you will still be pleading to the world when the hell will we finally do something.

If you live to 150 years old you will continue year after year to do the same all the way down to 1 billion or less humans on the planet.

Still pleading that we do something when all along something external of human agency was being done......... the solutions are going to be happening in the very consequences that will correct our over population.

All these questions about when humans will do something is putting the cart before the horse.

Only a culture transformed through the gristmill of consequences will be honed to perhaps, maybe, just maybe, tend to their long term sustainability on our planet.

That is if the climate consequences keep enough pockets of humanity around to finally answer your question.

Dohboi, there is no reason to beat your head against the wall any longer. Why don't you join Plantagent and fly down here to Panama and cleanse your mind with some wanderings through primary cloud forest where mountain lions and jaguars and Baird's Tapir still roam along forest trails while Resplendent Quetzals and Three Wattled Bell Birds raise the next generations young.
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Re: Global Warming / Climate Changes Pt. 21

Unread postby dohboi » Tue 04 Jun 2019, 13:57:55

Oh sweet Darth, rrr, Ibon. I'm not quite ready to go completely over to the dark side yet :)

Even if my mother is not just terminally ill but actually dead, I get no joy from dancing on her grave.

But you folks, go a head and dance to your hearts content with whatever stories and colors you have in your mind. :)
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Re: Global Warming / Climate Changes Pt. 21

Unread postby dohboi » Fri 07 Jun 2019, 22:00:25

Rapid Change in Coral Reefs Prompts Global Calls for a Rethink

https://phys.org/news/2019-06-rapid-cor ... lobal.html

Coral reef experts from around the world are calling for an urgent re-evaluation of our climate goals in the light of increasing evidence of unprecedented speed of change to these fragile ecosystems.Coral reefs, which have functioned relatively unchanged for some 24 million years, are now going through profound changes in their make-up.

Writing in a special feature of Functional Ecology, some of the world's leading coral reef experts are asking searching questions about the priorities for reef conservation and reef ecology in the face of these recent and rapid changes, which have far exceeded predictions.

The scientists address issues such as how we should actually define what comprises a functioning coral reef in the Anthropocene, an era where humans are the dominant force of planetary change.
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Re: Global Warming / Climate Changes Pt. 21

Unread postby dohboi » Fri 14 Jun 2019, 20:56:08

Apologies to anyone whose psyches are too delicate to handle negative info:

Climate Change Poses Major Risks to Financial Markets, Regulator Warns


https://www.nytimes.com/2019/06/11/clim ... -risk.html

WASHINGTON —
A top financial regulator is opening a public effort to highlight the risk that climate change poses to the nation’s financial markets, setting up a clash with a president who has mocked global warming and whose administration has sought to suppress climate science.

Rostin Behnam, who sits on the federal government’s five-member Commodity Futures Trading Commission, a powerful agency overseeing major financial markets including grain futures, oil trading and complex derivatives, said in an interview on Monday that the financial risks from climate change were comparable to those posed by the mortgage meltdown that triggered the 2008 financial crisis.

“If climate change causes more volatile frequent and extreme weather events, you’re going to have a scenario where these large providers of financial products — mortgages, home insurance, pensions — cannot shift risk away from their portfolios,” he said. “It’s abundantly clear that climate change poses financial risk to the stability of the financial system.”

... On Wednesday, Mr. Behnam plans to detail the formation of a panel of experts at the trading commission assigned to produce a report on how global warming could affect the financial sector, potentially impacting food costs, insurance markets, the mortgage industry and other economic pillars.

Because the report, expected late this year or early next, would be a product of the federal government, it would most likely put Mr. Behnam in direct conflict with the policies of the Trump administration. The report, which Mr. Behnam said he expected would focus in particular on potential harm to the nation’s agriculture sector, is likely to emerge at a moment when Mr. Trump will be making the case to farm states, which have already been hurt by his crop tariffs, to re-elect him in 2020.

... “We understand that climate change causes a big systemic risk,” said Stefano Giglio, a professor of finance at Yale University who has published studies with the National Bureau of Economic Research on the financial consequences of warming. “But right now, we don’t have enough information, and we don’t have the right financial products to insure this risk. The CFTC can help give that information and help lay out a global marker for what we need to do.”
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Re: Global Warming / Climate Changes Pt. 21

Unread postby jedrider » Sat 15 Jun 2019, 00:18:24

But right now, we don’t have enough information, and we don’t have the right financial products to insure this risk.


Civilizational Collapse Insurance. Every advanced civilization should have this.

Extinction Insurance. Every species should have this. Are you adequately covered?
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Re: Global Warming / Climate Changes Pt. 21

Unread postby dohboi » Sat 15 Jun 2019, 14:11:52

Nice one, jed.

And I must proffer yet more apologies for yet more science-based speculations on catastrophe:

Will CC kill everyone?

...lots of climate policy analysts agree that the IPCC is too optimistic. In particular, the IPCC has kept insisting that it’s still possible to keep warming under 2 degrees Celsius when at this point, that’s really unrealistic. As my colleague David Roberts put it:

Models have often included unrealistically low estimates of current and future emissions growth, unrealistically early peaks in global emissions, and unequitable estimates of emission curves in developing countries (implicitly assuming stunted development). ... Models routinely show 4 or even 6 percent annual reductions, a rate of emissions decline that has never been achieved by anyone, anywhere, ever, much less consistently over 50 years.

So it’s not surprising that some people got interested in more pessimistic models. What if we assume that we don’t get our emissions under control? What if we assume that there are severe “feedback cycles” where warming causes the release of carbon dioxide currently contained in the land and in the oceans, fueling further warming? And what if, instead of trying to model the most likely outcome, we look at outcomes that may only have a 10 percent chance of occurring but would be particularly disastrous if they did?

The Breakthrough report, authored by former fossil fuel executive Ian Dunlop and author David Spratt, for the most part summarizes cases for pessimism that have been raised in other papers and public statements.

It says, for example, “attention has been given to a ‘hothouse Earth’ scenario, in which system feedbacks and their mutual interaction could drive the Earth System climate to a point of no return, whereby further warming would become self-sustaining. This ‘hothouse Earth’ planetary threshold could exist at a temperature rise as low as 2°C, possibly even lower.”

“Our argument is in essence that on the present path, including the commitments in Paris, warming will be three or three and a bit degrees,” Spratt told me. “If you include climate cycle feedbacks, which are not included in the IPCC analysis, it’ll be effectively higher.” For both those claims, there’s significant published science backing him. Then he gets to the controversial bit: “Three degrees may end our civilization.” ...


https://www.vox.com/future-perfect/2019 ... ntial-risk
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Re: Global Warming / Climate Changes Pt. 21

Unread postby dohboi » Sat 15 Jun 2019, 14:23:16

Please note that the above article goes on to have a nuanced discussion of the various positions that various scientists who have looked at this issue have taken. I am not here saying that one or the other position is the most likely.

I will say, though, that when the author towards the ends of the article proclaims, "Climate change won’t kill us all," he is, imo, going beyond we can know for certain.
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Re: Global Warming / Climate Changes Pt. 21

Unread postby dohboi » Sun 16 Jun 2019, 13:47:48

An insightful (to me) comment by geront at asif:

Every day the USA has a few more climate refugees - not immigrants, citizens of the USA.

A street in Charleston? is zoned for demolition and to be returned to wetland. The houseowners are being paid off and leaving.

In New Jersey the government is still trying to get houseowners to move as where they live cannot be protected from the next surge.

Some farmers and residents along the USA's great rivers have been flooded out once too often and for too long. They are abandoning the land - i.e. they are climate refugees.

This is the here and now, not some Armageddon in the future.

It will get worse before it gets better. It will only get better if people get off the fence and DO something about it.
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Re: Global Warming / Climate Changes Pt. 21

Unread postby jedrider » Mon 17 Jun 2019, 17:20:50

This is the here and now, not some Armageddon in the future.


Well, I was just there in France. Yes, the weather was a bit wild, going from one extreme to another rapidly (day-to-day). Of course, any day could be considered within norms all by itself, but the rapid here-and-there, I've never heard anyone describe France's weather like that. I get home and the same in Northern California. I would think it's my imagination if not for the record flooding events in the U.S.A.

France to declare natural disaster after storms rip through crops
https://www.theguardian.com/world/2019/jun/16/france-to-declare-natural-disaster-after-storms-rip-through-crops
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Re: Global Warming / Climate Changes Pt. 21

Unread postby Plantagenet » Mon 17 Jun 2019, 18:03:04

“Our argument is in essence that on the present path, including the commitments in Paris, warming will be three or three and a bit degrees,” Spratt told me. “If you include climate cycle feedbacks, which are not included in the IPCC analysis, it’ll be effectively higher.” .....Then he gets to the controversial bit: “Three degrees may end our civilization.” ...

https://www.vox.com/future-perfect/2019 ... ntial-risk


Actually, the signers of the Paris Accords simply asserted that the climate would not be allowed to warm more than 2°C. There were no actual commitments in the Paris Accords....there were voluntary pledges, which many countries are already breaking.

Unfortunately, using the UN climate treaty process to set a phony limit on temperature instead of making a treaty to reduce CO2 emissions has proven to be short sighted and now we all will have to pay the price, which will potentially be very very high.

Cheers!
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Re: Global Warming / Climate Changes Pt. 21

Unread postby ozcad » Wed 19 Jun 2019, 13:18:27

JR said
Extinction Insurance. Every species should have this. Are you adequately covered?

I have an occasional image of my being stuck on the railway tracks, tied at the ankle to a "well adjusted" person who will not budge, even though we can both see the train approaching.
W.A.P. says "our sacred day of reckoning approaches".
I say "if we try hard enough we may get off the tracks and just lose a lot of skin".
W.A.P.: "It is folly and unseemly to try".
Me: If we had started earlier, instead of arguing, we might have made it. Now we are going to lose limbs".
W.A.P.: "We must accept our ordained fate".
Me: "You W.A.P.s produce the same delaying effect as the GW deniers".
W.A.P.: "the train is the agent of our philosophical maturation and learning".
The train looks bigger.
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Re: Global Warming / Climate Changes Pt. 21

Unread postby asg70 » Wed 19 Jun 2019, 13:33:07


HALL OF SHAME:
-Short welched on a bet and should be shunned.
-Frequent-flyers should not cry crocodile-tears over climate-change.
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Re: Global Warming / Climate Changes Pt. 21

Unread postby dohboi » Wed 19 Jun 2019, 14:33:53

Good one, oz.

Trigger warning for any sensitive souls out there--the following projects bad things coming down the pike:

High Temperature Records Will Be 'Smashed' in Coming Century


https://phys.org/news/2019-06-high-temp ... ntury.html
https://www.nature.com/articles/d41586-019-01891-3

Climate change will cause some regions of the world to "smash" high temperature records every year in the coming century, researchers warn. That will push "ecosystems and communities beyond their ability to cope," according to the authors of the study published online June 17 in Nature Climate Change.

The researchers used 22 climate models to forecast future summer temperatures. They determined that by the end of the 21st century, temperature events "will be so extreme that they will not have been experienced previously."

High monthly mean temperature records will be set in 58 percent of the world every year, with the greatest impact in developing countries and small island nations, according to the researchers. The highest monthly mean temperature records will occur in 67 percent of the least developed countries and 68 percent of small island developing states.
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Re: Global Warming / Climate Changes Pt. 21

Unread postby dohboi » Wed 19 Jun 2019, 21:06:33

Not too surprising, when you think about it:

Global warming has increased global economic inequality


Noah S. Diffenbaugh and Marshall Burke

PNAS May 14, 2019 116 (20) 9808-9813; first published April 22, 2019 https://doi.org/10.1073/pnas.1816020116

"...poorer countries or individuals are more negatively affected by a changing climate, either because they lack the resources for climate protection (3) or because they tend to reside in warmer regions where additional warming would be detrimental to both productivity and health."
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Re: Global Warming / Climate Changes Pt. 21

Unread postby dohboi » Wed 03 Jul 2019, 16:53:45

The linked reference uses improved modeling of the stratospheric chemistry-climate interactions in the hot climate conditions of the Eocene and recommends that such improved modeling of the stratospheric chemistry be included in climate models projecting the future. What is important to remember is that current consensus climate model projections of the future do not accurately account for stratosphere-climate interactions under hot climate conditions; which increases our collective climate risks:

Szopa, S., Thiéblemont, R., Bekki, S., Botsyun, S., and Sepulchre, P.: Role of the stratospheric chemistry–climate interactions in the hot climate conditions of the Eocene, Clim. Past, 15, 1187-1203, https://doi.org/10.5194/cp-15-1187-2019, 2019.

https://www.clim-past.net/15/1187/2019/

The stratospheric ozone layer plays a key role in atmospheric thermal structure and circulation. Although stratospheric ozone distribution is sensitive to changes in trace gases concentrations and climate, the modifications of stratospheric ozone are not usually considered in climate studies at geological timescales. Here, we evaluate the potential role of stratospheric ozone chemistry in the case of the Eocene hot conditions. Using a chemistry–climate model, we show that the structure of the ozone layer is significantly different under these conditions (4×CO2 climate and high concentrations of tropospheric N2O and CH4). The total column ozone (TCO) remains more or less unchanged in the tropics whereas it is found to be enhanced at mid- and high latitudes. These ozone changes are related to the stratospheric cooling and an acceleration of stratospheric Brewer–Dobson circulation simulated under Eocene climate. As a consequence, the meridional distribution of the TCO appears to be modified, showing particularly pronounced midlatitude maxima and a steeper negative poleward gradient from these maxima. These anomalies are consistent with changes in the seasonal evolution of the polar vortex during winter, especially in the Northern Hemisphere, found to be mainly driven by seasonal changes in planetary wave activity and stratospheric wave-drag. Compared to a preindustrial atmospheric composition, the changes in local ozone concentration reach up to 40 % for zonal annual mean and affect temperature by a few kelvins in the middle stratosphere.
As inter-model differences in simulating deep-past temperatures are quite high, the consideration of atmospheric chemistry, which is computationally demanding in Earth system models, may seem superfluous. However, our results suggest that using stratospheric ozone calculated by the model (and hence more physically consistent with Eocene conditions) instead of the commonly specified preindustrial ozone distribution could change the simulated global surface air temperature by as much as 14 %. This error is of the same order as the effect of non-CO2 boundary conditions (topography, bathymetry, solar constant and vegetation). Moreover, the results highlight the sensitivity of stratospheric ozone to hot climate conditions. Since the climate sensitivity to stratospheric ozone feedback largely differs between models, it must be better constrained not only for deep-past conditions but also for future climates.
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Re: Global Warming / Climate Changes Pt. 21

Unread postby dissident » Wed 03 Jul 2019, 20:28:03

Interesting results. The stratosphere does affect the lower troposphere circulation even though it is in the low mass "tail". The stratospheric polar vortex state affects surface pressure in the middle and high latitudes and the North Atlantic Oscillation and the Southern Oscillation.

https://agupubs.onlinelibrary.wiley.com ... 01GL014284

Even though the density of the atmosphere falls off exponentially with height, one cannot fob off the upper layers based on their total mass. The system is complex and includes Rossby wave reflection based on the zonal wind distribution the lower stratosphere above the tropopause. Quasi-stationary Rossby waves carry an enormous amount of energy (they are planetary in scale) and can either propagate into the stratosphere and be dissipated by thermal and mechanical damping (wave breaking) or get substantially reflected back into the troposphere. This is enough to change the storm tracks (baroclinic eddy propagation pathways) in the troposphere which is an in-your-face impact on weather.

This coupling between the low-density upper atmosphere and high-density lower atmosphere has impacted even weather forecasting. To properly simulation tropospheric synoptic scale features (e.g. baroclinic eddies) you need to put the lid no lower than 10 hPa or about 30 km. That is way above the tropopause. But even that is too low and modern forecast models have their lids at 0.1 hPa or about 60 km. If the lid is at 30 km the Brewer-Dobson (BD) circulation is too strong and that effects the state of the upper troposphere and lower stratosphere. The reason the BD circulation is too strong is that Rossby waves cannot propagate higher and towards the equator (the tend to follow great arcs) and deposit their energy lower down and at higher latitudes. The Coriolis torque is how the waves induce a meridional diabatic (e.g. BD) circulation through the damping of stratospheric westerly winds.
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