[dohboi]

"Ice is a huge heat sink before it melts, so every cubic meter melted reduces the heat sink capacity, which is a current negative feed back."

Yep, one that will suddenly switch to a positive feedback once it is all (or almost all) gone.

Thanks for the other clarifications. As I suspected, we are mostly on the same page.

One of the problems with just looking at the Miocene as where we are heading is that the rate of change is going to be (in some cases, such as ocean acidification, already is) much faster than pretty much any global change seen since the development of complex life on earth.

ETA: Here's a piece on the term 'Anthropocene' with famous POer Richard Heinberg.

http://www.resilience.org/stories/2014- ... thropocene

[Pops]

Perhaps sticking to reading up on Joan's latest coiffure would be safest after all?

If the options are reading endless posts about the inevitability of boilin in our skins rather than personal efforts to avoid such, then yeah, I'll take Joan's coif.

[dohboi]

Not to disappoint:

"Could we be facing a kind of ecological slapdown?

...Most of the serious environmental scientists that I've talked to... have pretty much resigned themselves to the fact that that's where we're headed."

Heinberg at 22:33 in the audio linked above and here: http://www.resilience.org/stories/2014- ... thropocene

So, if you want to avoid eco-doomy messages, be sure not to talk to any of the scientists that actually study the issue.

But really, what was Joanie thinking with that doo?

I do want to say I really appreciate your vast hands-on knowledge of how to live closer to sustainable means and to prepare oneself for rough times ahead (or already here).

I've also done more than most people who I know of to, by "personal efforts,...avoid such" in the sense of avoiding contributing to the problem. But I also know that personal efforts can only go so far.

[rockdoc123]

But the rate of sea level rise has been accelerating, so the rise is likely to be more than 25 cm---perhaps 0.5 m or more.

actually it hasn't been accelerating, I"ve posted several references to recent publications that demonstrate this to be the case. There are cycles in the rate which seem to be repeated.

Irrespective of that the IPCC study takes into account most of what has been written since AR4 (and before when relevant). This presumably is the state of art thinking at this point in time given the sea level chapter has contributions from many experts in this particular field. I've noted that sometimes articles are not referenced that might disagree with their final judgement on a particular topic but overall one has to admit this is as close as it gets. Any other doom and gloom you want to propose such as the nonsense that Greenland alone will provide 7 m by 2100 is nothing more than wild ass speculation not based on any published science as far as I can tell.

As to people who built on beaches in vulnerable spaces.....whose fault is that? Were they required to live there? Did they not do any risk evaluation when they built/bought? We had a ton of people this past year in Alberta who had homes on flood plains or at best marginal flood plains that suffered extensive damage whining for all to hear "how were we ever going to expect this?".

[ritter]

Tanada,

As you say, observations of effect are running 20 years behind cause. It's hard to know what to expect from the new 402 ppm. I guess we'll know in 20 years.

If the current California drought is indicative of where we're headed (and recent research indicates CC's finger prints on it), life as we've known it is done. We're looking at 40% of the Central Valley being left fallow this year. Our snow pack is at 18% of normal and it's not even summer yet. If we get drought again next year, it will be worse. If we get a strong el nino, we may get the biblical flooding instead. Either way, California agriculture is likely going to take another blow next year. And we are not unique to recent drought/flood extremes.

On other fronts, I'm pretty convinced climate change is occurring too fast for effective plant adaptation. Without the plant habitats they are dependent on, many Animalia species will vanish as well. It's hard to know if homo sapiens will be one of them.

I'm somewhat at a loss as to how one prepares for such a future. So I muddle along and try to take meaningful actions in my home and community to build climate reliance.

[Newfie]

How Can I buy Property in Greenland ?!?!

I don't know about Greenland but acreage in Newfoundland is dear, but the housing is cheap.

Relatively cheap land can be found in Nova Scotia and New Brunswick.

Just bring money, you don't need to be a citizen or a landed immigrant.

[Tanada]

Irrespective of that the IPCC study takes into account most of what has been written since AR4 (and before when relevant). This presumably is the state of art thinking at this point in time given the sea level chapter has contributions from many experts in this particular field. I've noted that sometimes articles are not referenced that might disagree with their final judgement on a particular topic but overall one has to admit this is as close as it gets. Any other doom and gloom you want to propose such as the nonsense that Greenland alone will provide 7 m by 2100 is nothing more than wild ass speculation not based on any published science as far as I can tell.

I have posted repeatedly in this and other threads that it could take 1,000 years for Greenland to all melt so why you keep obsessing on 2100 is beyond my understanding. 2100 or 3100 we will all be dead by then so we are talking about what the world will be like for our descendents, not ourselves. At no time in the paleoclimate record has Greenland been glaciated when atmospheric CO2 exceeded 400 ppmv. That is a well established condition so I don't see any point in arguing about it.

When Greenland melts world average sea level will rise 7 meters, mostly around the equatorial bulge. When the West Antarctic Ice Sheet melts you can add in another 5 meters, and because the grounding line is already below sea level it is now believed that if the WAIS collapses the process will be rapid, on the order of decades, not centuries or millennia. Will any serious melting take place before 2100? I hope not, but given the speedy collapse of the Arctic Sea Ice in the last decade I am not at all convinced things will go along in the slow manner predicted by the IPCC. Having open water in the Arctic in the fall causes significant changes in the weather patterns that impact on Greenland. If those impacts lead to more cloud cover and more snow in winter then the GIS will last longer than predicted. If those changes lead to clear sunny days and above freezing temperatures during the peak of summer then the GIS will melt significantly faster than currently expected. Model results are all over the place so the truth is nobody has a clue what scenario is most likely to unfold.

[kiwichick]

i'm happy to go with Hansen's 5 metres by 2100 ...... for now

[ralfy]

"Earth Will Cross the Climate Danger Threshold by 2036"

http://www.scientificamerican.com/artic ... d-by-2036/

[rockdoc123]

I have posted repeatedly in this and other threads that it could take 1,000 years for Greenland to all melt so why you keep obsessing on 2100 is beyond my understanding

please just look at the posts from dissident (claimed 7 m by 2100 in a post just above yours) and kiwichick (claimed 5 m by 2100) on this thread and then literally scores of posts from other alarmists on other related threads.

Indeed I think it was either dohboi or lore who were completely adamant that over a metre by 2100 was guaranteed. What I point out is the current understanding is that is not the case.

Interestingly enough a recent paper suggests that the Greenland ice sheet has not disappeared for at least 3 MY even though temperatures throughout the last 6000 years or so in Greenland have been warmer by a couple of degrees than currently (according to oxygen isotope temperatures from GISP 2).

Bierman, P. R. et al, 2014, Preservation of a Preglacial landscape under the center of the Greenland Ice Sheet, Science, DOI: 10.1126/scienc.1249047

Continental ice sheets typically sculpt landscapes via erosion; under certain conditions, ancient landscapes can be preserved beneath ice and can survive extensive and repeated glaciation. We used concentrations of atmospherically produced cosmogenic beryllium-10, carbon, and nitrogen to show that ancient soil has been preserved in basal ice for millions of years at the center of the ice sheet at Summit, Greenland. This finding suggests ice sheet stability through the Pleistocene (i.e., the past 2.7 million years). The preservation of this soil implies that the ice has been non-erosive and frozen to the bed for much of that time, that there was no substantial exposure of central Greenland once the ice sheet became fully established, and that preglacial landscapes can remain preserved for long periods under continental ice sheets.

so I have no problem with your reasonable approach....hey it might happen in a few thousand years (but because climate is chaotic and all the driving forces aren't well understood at this point in time my guess are all bets are off). What I have a problem with is the doom and gloomers here who choose to ignore the science but hang their hat on alarmist comments that aren't backed up by any of the projections.

[dissident]

"Earth Will Cross the Climate Danger Threshold by 2036"

http://www.scientificamerican.com/artic ... d-by-2036/

The article still gets it wrong on the phoney "stall". There was a nice set of posts here debunking this trope. If you fit a line to the trend from 1980 until now you see that the temperature increases never stalled. The warming trend increased for about 10 years starting in the mid 1990s and this increased trend anomaly was gone by the mid 2000s. Human brain pattern recognition does not fit a proper trend line to the trend but follows the outer edge of the temperature anomaly time series (i.e. the peak values) and fits a curve which gives the illusion of a stall in the warming after 1998. The 1998 ENSO outlier does not help.



http://tamino.wordpress.com/2014/01/30/ ... -surprise/

This 1995-2005 increased trend anomaly does not render the longer term trend irrelevant. Such variations are perfectly consistent with ENSO-like and PDO-like long term exchanges of heat between the oceans and the atmosphere.

[Plantagenet]

But the rate of sea level rise has been accelerating, so the rise is likely to be more than 25 cm---perhaps 0.5 m or more.

actually it hasn't been accelerating

Yes it has. The global data show that sea level is rising and the rate of sea level rise is gradually increasing.

In the following plot the rate of rise is shown graphically by the slope of a series of lines fitted to the sea level data. The fitted lines progressively get steeper indicating the rate of sea level rise increased through the 20th century, and the pattern looks set to continue into the current century. The most recent data show sea level is currently rising about 3 mm/yr, higher then any prior rate determined at any period in the 19th and 20th centuries.


the rate of sea level rise is gradually increasing.

[Tanada]

But the rate of sea level rise has been accelerating, so the rise is likely to be more than 25 cm---perhaps 0.5 m or more.

actually it hasn't been accelerating

Yes it has. The global data show that sea level is rising and the rate of sea level rise is gradually increasing.

In the following plot the rate of rise is shown graphically by the slope of a series of lines fitted to the sea level data. The fitted lines progressively get steeper indicating the rate of sea level rise increased through the 20th century, and the pattern looks set to continue into the current century. The most recent data show sea level is currently rising about 3 mm/yr, higher then any prior rate determined at any period in the 19th and 20th centuries.


the rate of sea level rise is gradually increasing.

Has anyone made a tide gauge record for an equatorial location like the mouth of the Amazon or perhaps on Java island in Indonesia? Such a record could prove invaluable to confirm or refute the meme that sea level rise will be substantially greater at the equatorial bulge than at the poles due to the change in local gravity fields due to ice mass loss.

[Tanada]

I have posted repeatedly in this and other threads that it could take 1,000 years for Greenland to all melt so why you keep obsessing on 2100 is beyond my understanding

please just look at the posts from dissident (claimed 7 m by 2100 in a post just above yours) and kiwichick (claimed 5 m by 2100) on this thread and then literally scores of posts from other alarmists on other related threads.

Indeed I think it was either dohboi or lore who were completely adamant that over a metre by 2100 was guaranteed. What I point out is the current understanding is that is not the case.

Interestingly enough a recent paper suggests that the Greenland ice sheet has not disappeared for at least 3 MY even though temperatures throughout the last 6000 years or so in Greenland have been warmer by a couple of degrees than currently (according to oxygen isotope temperatures from GISP 2).

Bierman, P. R. et al, 2014, Preservation of a Preglacial landscape under the center of the Greenland Ice Sheet, Science, DOI: 10.1126/scienc.1249047

Continental ice sheets typically sculpt landscapes via erosion; under certain conditions, ancient landscapes can be preserved beneath ice and can survive extensive and repeated glaciation. We used concentrations of atmospherically produced cosmogenic beryllium-10, carbon, and nitrogen to show that ancient soil has been preserved in basal ice for millions of years at the center of the ice sheet at Summit, Greenland. This finding suggests ice sheet stability through the Pleistocene (i.e., the past 2.7 million years). The preservation of this soil implies that the ice has been non-erosive and frozen to the bed for much of that time, that there was no substantial exposure of central Greenland once the ice sheet became fully established, and that preglacial landscapes can remain preserved for long periods under continental ice sheets.

so I have no problem with your reasonable approach....hey it might happen in a few thousand years (but because climate is chaotic and all the driving forces aren't well understood at this point in time my guess are all bets are off). What I have a problem with is the doom and gloomers here who choose to ignore the science but hang their hat on alarmist comments that aren't backed up by any of the projections.

Fair enough, we each come to the table with our own innate and learned biases that influence how we see the past present and future. I am cognizant of the 3 Million year horizon for the Greenland ice sheet, my concern comes down to the knowledge that current CO2 levels are far in excess of what they were 3 Million years ago when the Straits of Panama closed and the Greenland interior first began to accumulate a permanent ice sheet. It does not appear that the ice cap on Greenland took more than a millennia or so to become a major climate impact and it does appear that about a third of it melted during the penultimate interglacial 125,000 years before present. At that time the Milankovich cycles all aligned for maximum summer insolation at 65 degrees North latitude while the natural variation of CO2 is believed from the proxy record and captured gasses measured in the Antarctic and Greenland ice cores to have been 290 ppmv.

Dr. David Archer has calculated exactly what summer insolation values would have existed at 125,000 ybp from the Milankovich forcing coupled with the 290 ppmv CO2 forcing. He used to have the program for the calculations up on the University of Chicago website but I do not know if it is still active. Current values from the CO2 forcing coupled with the modern Milankovich insolation values exceed the threshold values he calculates for the great Greenland melting that took place 125,000 ybp and he has written that Greenland will inevitably melt unless these CO2 levels are brought down well below 350 ppmv or some geoengineering effort reduces the solar insolation. Nowhere have I seen him claim that this will take place in a very short time interval and as he is a trained specialist who spends a great deal of his time working on this data I accept his conclusion. He does however caution his readers that he could be too conservative in his estimates of about 1,000 years for the melt to take place.

[rockdoc123]

The article still gets it wrong on the phoney "stall". There was a nice set of posts here debunking this trope. If you fit a line to the trend from 1980 until now you see that the temperature increases never stalled.

Yes we talked about this and the analysis from Tamino is complete and utter crap although it panders to what you want to have happen. If there is no pause why does Trenberth recognize it? Why does Gavin Schmidt recognize it? Judith Curry and pretty much everyone else you can think of? How about the IPCC WG I which dedicated a paragraph or two to the pause? The IPCC recognizes there has been a pause but apparently they are wrong? All those experts, imagine that?

Yes it has. The global data show that sea level is rising and the rate of sea level rise is gradually increasing.

Well you might want to take that up with some of the scientists who work with the data . Here is the most recent:


Cazenave, A, et al, 2014. The rate of sea-level rise. Nature Climate Change, doi:10.1038/nclimate2159

Present-day sea-level rise is a major indicator of climate change1. Since the early 1990s, sea level rose at a mean rate of ~3.1 mm yr−1. However, over the last decade a slowdown of this rate, of about 30%, has been recorded. It coincides with a plateau in Earth’s mean surface temperature evolution, known as the recent pause in warming. Here we present an analysis based on sea-level data from the altimetry record of the past ~20 years that separates interannual natural variability in sea level from the longer-term change probably related to anthropogenic global warming. The most prominent signature in the global mean sea level interannual variability is caused by El Niño–Southern Oscillation, through its impact on the global water cycle. We find that when correcting for interannual variability, the past decade’s slowdown of the global mean sea level disappears, leading to a similar rate of sea-level rise (of 3.3 ± 0.4 mm yr−1) during the first and second decade of the altimetry era. Our results confirm the need for quantifying and further removing from the climate records the short-term natural climate variability if one wants to extract the global warming signal1

There are a number of papers that speak to the cyclicity in sea level rise, a number of which I posted previously. Obviously I was wasting my time.

In any event another recent paper speaks to why a global measure of sea level rise may be somewhat irrelevant:

Woppelmann, G, et al, 2014. Evidence for a differential sea level rise between hemispheres over the 20th century. Geoph Res Lett, V41, 5, pp 1639-1643

Tide gauge records are the primary source of sea level information over multi-decadal to century timescales. A critical issue in using this type of data to determine global climate-related contributions to sea level change concerns the vertical motion of the land upon which the gauges are grounded. Here we use observations from the Global Positioning System for the correction of this vertical land motion. As a result, the spatial coherence in the rates of sea level change during the 20th century is highlighted at the local and the regional scales, ultimately revealing a clearly distinct behavior between the northern and the southern hemispheres with values of 2.0 mm/year and 1.1 mm/year, respectively. Our findings challenge the widely accepted value of global sea level rise for the 20th century.

[Lore]

I see our future threat as a little more immediate. We don't need all of Greenland's ice to melt to create some serious consequences as a result of SLR.

I'll caption as an example from our favorite US poster child in the news, Miami, FL You can repeat this scenario for most of the world's industrialized countries coastal areas.

Florida Senator holds Miami Beach hearing on rising sea level

MIAMI BEACH Tue Apr 22, 2014 5:36pm EDT

(Reuters) - Climate change is already impacting south Florida coastal communities, which could see a three-foot rise in sea level by the end of the century, a panel of officials and scientists testified at a Senate hearing on Miami Beach on Tuesday.

"This is ground zero for sea-level rise," said Senator Bill Nelson, who hosted the hearing of the Senate Subcommittee on Science and Space at Miami Beach City Hall.

Part of a series of statewide meetings organized by Nelson, the hearing coincided with Earth Day.

Florida had recorded between five and eight inches of sea level rise in the last 50 years, said Miami-born Nelson, noting that 75 percent of the state's population live near the coast.

"We'd best get about the process of recognizing what is happening all around us," the Democratic lawmaker said.
[This of course is not what wealthy developers in the area want to hear. One of the reasons North Carolina legislators decided to remove any reference to SLR risk from their coastal plans. It certainly won't stop the NC Outer Banks from disappearing by the end of the century.]

The low-lying greater Miami area, with a population of 5.7 million, is one of the world's most at-risk from flooding urban communities, environmental studies show.
[So, if over half of the population that can abandon the area by mid century, what becomes of those left behind in a jobless, rundown, toxic environment?]

The United States Geological Survey has warned that sea level could rise by two feet by 2060.
[This is more than enough sea level rise to devastate the near beach coastal areas and push sea water into fresh ground water resources. Also, say goodbye to the Florida Keys.]

Sea level could rise by up to three feet by 2100, Piers Sellers, a deputy director for Sciences and Exploration at NASA's Goddard Space Flight Center, told the hearing.
[This coincides with the high end of the IPCC assesment in AR5, scenario RCP8.5, mean 74cm, range 52-98, which is up from the estimate of AR4.]

A one-foot rise would threaten $4 billion of south Florida's property tax base, while a three-foot rise would put $31 billion of property at risk, said former Broward County mayor Kristin Jacobs.
[I believe the mayor's estimate here is quite conservative, since who is going to stick around if they can move to see their property value go to $0?]

While the insurance industry has yet to fully factor climate change into premiums, that is gradually changing, Megan Linkin, Natural Hazards Expert at the reinsurance firm, Swiss Re Global Partnerships, told the hearing.
[Insurance, or lack of will prevent any new projects from getting underway let alone keep any existing residential and business owners in place. No one is going to purchase or loan money to property that cannot be insured]

The risk to coastal communities was "indisputably growing," she said, calculating that it threatened $6.6 trillion in coastal property and 55 million jobs in the United States.
[This spells economic collapse.]

Miami Beach, at an average elevation of 4.4 feet, with 7 miles of beaches, was already seeing more frequent salt-water street-flooding at high tide, said Miami Beach mayor Philip Levine. He added that it was a threat to the city's tourism industry, which drew $9 billion in revenue last year.
[Don't feel alone Phil, there won't be much tourism anywhere by mid century. Everyone will be too busy at home, beating off squatters.]

With plans to invest $300 million to $400 million in upgraded salt water pumping systems, Levine called climate change mitigation his "top priority."
[More like a losing proposition, because the rise in sea levels is already baked into the cake and it's not going to stop at 2100.]

After Hurricane Sandy washed away broad swaths of Florida beaches, cities are looking at a variety of options, from drainage ditches, taking water treatment and management systems further inland, or relocating residents in high-risk areas.

But even that may not be enough, said some in the audience.

South Florida's sea level rise is 50 percent above the global average, said climate scientist Robert Corell, a senior fellow at Florida International University and former member of the UN's International Panel on Climate Change. "The global average will go up 1 foot every 25 years according to latest global data."

Acknowledging Nelson's efforts, oceanographer John Englander, author of 'Hide Tide on Main Street' expressed disappointment that "we do so little so late."
[And so far, unless attitudes drastically change, that's exactly what we will do]

Talk of salt water pumps was "really like bailing the Titanic with a tin can," Englander said.

http://www.reuters.com/article/2014/04/ ... R120140422

[dohboi]

rd wrote: "there is no pause"

I'm glad that we are all in agreement on that, then.

Oh, you don't like being quoted out of context? Maybe then you shouldn't highlight the very passage of an abstract that are exactly what the paper is disproving.

Section you highlighted:

over the last decade a slowdown of this rate, of about 30%, has been recorded.

Actual thesis of the study:

We find that when correcting for interannual variability, the past decade’s slowdown of the global mean sea level disappears

"Obviously I was wasting my time."

Please do stop wasting your and all of our time by constantly misrepresenting and cherry-picking data.

[rockdoc123]

Oh, you don't like being quoted out of context? Maybe then you shouldn't highlight the very passage of an abstract that are exactly what the paper is disproving.

Well perhaps you should actually understand what it is you are reading before you beak off.

Fact: from measurements they demonstrate a slowdown (which was why I posted the article as someone here claimed that there was, in contrast, an acceleration)

Hypothesis: based on their modeling work they think it might be due to ENSO. It could also be due to any number of other elements but they chose to look at this particular one. It is what is referred to as a non-unique solution.

Why am I not surprised that you have difficulty separating out fact (measurements) from hypothesis of what explains that fact/observation?

I'll caption as an example from our favorite US poster child in the news, Miami, FL You can repeat this scenario for most of the world's industrialized countries coastal areas.

your confusing overall sea-level rise versus relative sea-level rise. Much of the SW coast of the US has been subject to subsidence as have many areas in the world. These areas could be at risk for flooding even if sea level stopped rising entirely . In a similar vein areas which are still subject to positive GIA might never have to worry.

[Plantagenet]

global sea level rise is absolute sea level rise. Don't worry about relative sea level rise.

[dohboi]

Wow, you seem to have lots of confusion yourself, there, as you equate 'fact,' 'measurement,' and 'observation.'

Perhaps an investment in a dictionary may help you out, or a few seconds spent checking common definitions.

Not really worth speaking further with one so utterly confused (or willfully trying to confuse others).