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Rob Dekker

Pyotr Kropotkin from SE Florida said

I do not believe I will ever be directly affected by sea level rise in my lifetime.

Considering that you have been "professionally involved with official preparations for sea level rise and emergency management. ", it seems that it already did.

Elisee Reclus

I misspoke.

What I meant was I don't expect that MY property will be under water during my lifetime; where I live I am safe even from storm surge in a big hurricane.

However, areas on the coast, particular on the barrier islands just off the mainland, have experienced local flooding when meteorological conditions (an offshore wind)
coincide with an extreme tide. In a big storm, sea level rise could lead to flooding that just a few years ago would have been unthinkable.

There is also the issue of sea levels rising above the water levels of the outlets of the many canals that drain the Everglades. Although these can carry flood water to the sea, they could conceivably allow sea water to flood the inland regions. And of course, there is always the possibility of salt water entering the aquifer that supplies much of our water, and of storm evacuation routes and bridges being overwhelmed. Just a few days ago, Miami Beach had water on the main drag between the hotel strip and the beach, and the weather was quite moderate, just a stiff offshore breeze and a perigee tide. This kind of event is not unheard of in this area, but it seems to be happening more and more often.

The measures being proposed to mitigate these problems (seawalls, pumps, canal flood gates,etc) are only stopgap measures. In an area where real estate and tourism are the major industries, these issues don't get too much national publicity, but I can assure you local government and businesses are sweating bullets.

Elisee Reclus

BTW, P-Maker:

I have never written any books.
I have had a few dozen magazine articles published, on themes unrelated to climate issues, but no books.

NeilT

In terms of being protected from the elements, I'm not so sure that we can be complacent.

If you've studied this they you will know that one of the prime tenets of the impacts of AGW is not that everything will go to hell tomorrow, on a schedule, with an event you can pinpoint. More that Events like Sandy, two storms merging, will become more common and find more extreme conditions to push ashore.

Add to that 4 - 8 inches of abrupt sea level rise and unless you are 20M over the MSL, you're in danger in extreme events.

One of the things I constantly have to remind people about, when talking about Climate Change and it's impact on our habitat, is refelected by the London Barrier. It is designed to survive a 1,000 year storm. But it was designed in the 60's driven by the east of England flooding in 53. So it was designed for parameters based on 1950's sea levels then modelled to cover the impact of a 1,000 year storm coming down the North Sea on the top of a spring tide.

All well and good. Except with Global Warming that 1,000 year storm may come round every 100 years. Then we have to factor in global sea level rise. The average since 1993 has been 3.2mm per year or 3.2cm per decade. By 2020 that's more than 3 inches alone. Add to it 4 decades of "normal" SLR (before 93), up to 1993 and now you are talking over 4 inches of sea leve rise. Minimum. Since those calculations were made.

If we continue with the current SLR rates, that will be 8" by 2046. However "averages" are decieving as the 3.2 figure is driven by 3.4 averages since the mid 2000's.

So come the 2040's, that 1000 year storm protection is going to look tenuous, with 8 inches of sea level rise, since it was designed. Or, given accelerating trends, will it be a foot. Or will it be more.

Perhaps, come the 2030's, when a storm comes roaring down the North Sean into the English Channel, on the top of a spring tide, we might see London flooded again; as it was in my youth.

My comfort zone is slightly better. I live inland, 80m above sea level and 30m above the local river. More importantly in the country an hours drive from the nearest large city and in a farm ing community.

P-maker

'Elisee Reclus',

please say hello to you 'missus from me' and - following up on Neil's fine remark - keep up the good work of moving further away from the coast in Florida.

Elisee Reclus

NeilT-

For those of you who are European residents, or not particularly familiar with the geography of the USA state of Florida, a bit of research might be helpful...

Florida is by nature low, flat country, and South Florida even more so. But the immediate danger here from sea level rise is not so much the rise itself as the intermittent storm activity superimposed on it. Long before we are forced to build a dyke around Manhattan to keep the ocean out, or changes in weather patterns start affecting mechanized agriculture, Florida will be suffering from the effects of even gradual and limited sea level rise.

Our bathymetry is not prone to catastrophic ocean flooding events from hurricanes because we are a straight, gradually sloping coastline without deep, quickly narrowing and shoaling estuaries such as on Florida's Gulf coast. This geomorphology, submerged relict river valleys, concentrate and project storm surge so that its damage is carried far inland.

But we have other problems here on the Atlantic. The natural protection from wave action offered by offshore coral reefs, barrier islands, coastal dunes and mangrove forests is no longer there. The reefs are dying from AGW and ocean acidity as well as pollution. The dunes and mangroves have been removed to free land for development, and the barrier islands transformed into high value targets by intensive high-rise construction (the hotels and resort industry that have made us a global tourist attraction).

A rise in sea level of even a meter might leave my neighborhood high and dry and my property untouched, but the entire region would be devastated economically, and most of its infrastructure and utilities crippled. Our sources of potable water, the Everglades and the Florida Aquifer, would be threatened by salt water intrusion. Some communities, like the Florida Keys, would be cut off entirely by losing their access to the mainland and might have to be abandoned altogether. The agricultural areas would lose their fresh water and have to be sacrificed. The Everglades, already drained and cleared for agriculture and development, would be unable to provide the water pressure to keep back the salt, so the local natural environment would continue to degrade, and eventually collapse. Even without sea level rise, these are significant problems today.

So I am well aware that even though my house might still be standing and dry after a meter of ocean level rise (the coast would still be several kilometers away); that does not mean my community would still be viable.

The overused analogy of the blissfully unaware frog in a pot of water gradually coming to a boil is cliched and trite, but right on nonetheless. Coupled with the fact that the necessary responses to these problems are expensive and will show no immediate results only complicates the issue. And of course, there is always human greed.

NeilT

Elisee, I'm still struggling to understand how you determine that your Geomorphology would protect you in, for instance, a Katrina style storm surge.

Granted I was not totally up to speed in the way in which storm surges attack land, but looking at the wiki page

https://en.wikipedia.org/wiki/Storm_surge

The words "A narrow shelf, for example, or one that has a steep drop from the shoreline and subsequently produces deep water in proximity to the shoreline, tends to produce a lower surge but a higher and more powerful wave"

Followed by "This situation well exemplified by the southeast coast of Florida. The edge of the Floridian Plateau, where the water depths reach 91 metres (299 ft), lies just 3,000 m (9,800 ft) offshore of Palm Beach, Florida; just 7,000 m (23,000 ft) offshore"

So in a scenario where a very large hurricane comes in, causing huge rainfall inland, before the surge, overloading the rivers and their ability to direct the surge, followed by a 15ft surge (Katrina size), and you are going to be in severe trouble. In fact even a 10 foot surge in a hurricane the size of Sandy is going to hurt because Sandy dropped incredible amounts of water inland before the surge struck.

Reading this article on surges

http://thevane.gawker.com/understanding-storm-surge-the-deadliest-and-most-overl-1726167166

Also would not give me the slightest certainty that I was safe.

Add to that the fact that the warmer atmosphere is allowing more moisture, which adds power, size and rainfall, to hurricanes and the likelihood that you are going to be hammered starts to become greater.

Add even half a meter of sea level rise to that and the eventual encroachment of the shore (long shallow shores encroach most with SLR) and you're starting to look like playing Russian Roulette with a 3 chamber revolver.

Yes it "might" not hit you. Then again your chances would have risen up to 300% that you would.

Not the kind of odds I'd like to play with.

Every time we are hammered with a new force of nature which we did not anticipate there is huge effort into finding out "why" it happened.

Yet a prudent approach would have told us all we needed to know 30 years ago. Yes we "might" not be impacted.

But is that any way to live?

Elisee Reclus

Neil

Thank you for the very good questions. Fortunately, this time I can give you some fairly good answers.

To begin with, the Katrina disaster was not caused by storm surge, it was caused by a failure of a levee (a dyke which protects an area that is below water level). The flooding in New Orleans, such as in the Ninth Ward, was in areas that were below sea level. When the levee broke, Lake Ponchartrain (actually, an arm of the sea) poured into the city. The water is already higher in the lake than it needs to be. The wind and waves only made it worse. If the levee had failed on a perfectly calm day, there still would have been flooding.

All of Florida is (by definition) above sea level. The only way the sea can overwhelm the land is locally, in one place where extremely high wind, and/or extremely low barometric pressure can temporarily force the water out of the ocean basin. But the entire ocean doesn't rise out of the sea, only that part of the sea affected by the storm winds--a limited amount.

Storm surges are particularly extreme in areas where the sea intrudes shallow and far into the land (see, on the Gulf Coast of Florida, Tampa Bay, Charlotte Harbor, and the Fort Myers area. This may also be the case near Pensacola and Panama City as well, but I'm not that familiar with the geography in the Panhandle.

To describe the process in simplistic terms,
if the wind speed is strong enough and the direction is just right, for long enough time, and if the tide cooperates, great amounts of water are shoved into a shallow bay that narrows (and shoals) quickly. All that water has nowhere to go but into the surrounding land, which is usually prime real estate and heavily developed.

This process is very well understood, and has been extensively modeled by government agencies. In fact, it was one of my jobs working for the County to use the results of these "storm surge models" to predict the extent and severity of water damage and to output different scenarios onto GIS maps for the use of emergency planners and officials who tried to persuade the business community into exercising some restraint before they developed these areas.

The situation you describe with the rapid shoaling of the continental shelf is a much smaller example of the dynamics I describe above, which is reflected by how the boundaries of our evacuation zones are drawn. Zone I is the barrier islands themselves, heavily populated and developed, and with only a few narrow and fragile bridges and causeways to get the people off.

A look at nautical charts of these islands reveal colorful place names at mysterious gaps in them, like "Hurricane Pass", or "Midnight Pass", where on some terrible night years ago a great sea punched a hole through the land. When I see all those hotels and condos on the barriers I think of them as a great breakwater.

Evacuation Zone II is from the lagoon between mainland and barrier island to the great wall formed by the interstate highway which runs N-S parallel to the coast. There is a potential for some storm surge there, but the raised crown of the highway acts a seawall, of sorts. Under the worst conditions, the flooding there may be locally devastating, but not too widespread. True, the Interstate berm is pierced at many places at the spots where major E-W arteries cross it, but the surge will simply not have the volume of water required to fill that entire strip completely. Its not the whole Atlantic which surges, just the piece affected by wind and tide.

Of course, due to AGW, these conditions will be more severe, and will occur more frequently, and cause more damage. No one is denying that.

As for rain flooding inland, that is another story altogether. Florida gets a lot of rain, and the drainage is designed to handle it. But the 30-40 cm we can get in just a few hours in a large storm can overwhelm it. If the drains and sewers clog with debris, the water will have nowhere to go, and if the drain outfalls are below sea level due to storm surge, they will quickly back up.

I'm not saying Florida is not at risk to climate change. On the contrary, it is highly vulnerable, and I've spent a good part of my professional life dealing with it. But we are very familiar with the damage caused by hurricanes here. Climate change will make the damage more severe, and more frequent, but it will be different in degree, not in kind--at least, for the near future. I'm much more concerned about agricultural disruption due to changes in weather patterns, particularly precipitation, affecting me directly in my lifetime. I will cross my Biblical three score and ten in just a few more months, and I think I'm already starting to see the beginnings of that disruption now.

Of course, once you are talking about a sea level rise on the order of a meter, then that's another case altogether.

NeilT

Thanks for the explanations. I'm well used to the local surge effects of the low pressure area within the eye wall and the "hump" it creates. I was not so aware of the wind driven build up which one of the articles I was reading told about.

However, you were calculating it so you should know. Although how many storms would you have planned for of the size of Sandy? Then again we did have the huge super typhoon in Australia a decade or so back so I guess there is some precedent to work from.

Elisee Reclus

Sandy was not a particularly big storm, as I recall, although the damage was quite dramatic. But hurricanes are difficult to classify, there are too many factors involved. The wind speed, tides, the sea state, and the nature of the sea bottom and shape of the coastline where they come ashore also affect the outcome.

The speed of the storm, as well as its size, plays a role, as well as how long it lingers over a particular area. And of course, the experience and preparation of the community where it strikes is also important: emergency services, building codes, and so on.

I've been through about a dozen, and the damage I've seen has never really correlated very well with their overall strength, or "category". Whether the destruction is primarily a result of wind or wave action, or flooding from rain, is also unpredictable.

The computer models we use are fed a projected storm's size, wind speed and speed-over-ground, as well as topographic and bathymetric information from the area of interest. The output is a series of GIS coverages and grids showing estimates of damage and severity. They are not very realistic for prediction, but they have great utility in planning and training.

Basically, its a big, chaotic, and totally unique phenomenon, and it is as difficult to predict the resulting damage as it is to predict the trauma caused by a bullet in tissue. Although I have never been hurt or suffered property damage (except Wilma ripped out my rain gutters and blew out one of the rear windows in my 1990 Sentra). Its like being in a car crash, you never know what the result will be.

Susan Anderson

Elisee, Pyotr, whoever. Thanks for the biography.

So why have you been stirring the pot with some of the nicest people on earth?

No need to answer, just saying ...

Elisee Reclus

Oh, Susanna

I don't understand, so I must answer.

Who are the 'nicest people on earth'? My former colleagues, or you folks here?

And what do you mean by 'stirring the pot'? Do you mean causing trouble? Moi?

You'll have to be more specific, I really don't understand your insinuendo.

I've been lurking here for a long time, Neven seems to really have his act together, and I have interests in the climate and AGW, both professionally and as a scientist and amateur historian. (Yes, this is history, the temporal analogue of geography.) So I decided to participate. But I seem to have gotten the reputation as some sort of denialist reactionary. Far from it. I'm just an anarchist geographer.

Joe_nilo


"Sandy was not a particularly big storm, as I recall, although the damage was quite dramatic."

You're quite wrong.

"At landfall, Sandy's tropical storm-force winds spanned 943 miles of the the U.S. coast. No hurricane on record has been wider; the previous record holder was Hurricane Igor of 2010, which was 863 miles in diameter."

https://www.wunderground.com/blog/JeffMasters/hurricane-sandys-huge-size-freak-of-nature-or-climate-change

Jai Mitchell

Sorry to see Vidaloo gone, he was a good chap. I can vouch for him, having heard his presentation via podcast. He does indeed believe that we will have a year-round ice free arctic condition in 4-7 years.

Of course, the only way that would happen is if we achieve some kind of bifurcation pulse change event, like a massive methane release or catastrophic transformation into an equable climate. Of course, this kind of a black swan event cannot be predicted using average values, unless there is a magical law of natural averages that suddenly translates a summer sea ice minimum from zero to a negative value (and hence reducing the 'average' even further for the annual).

But he MAY be right, we simply do not know what the future holds in this transformation of our global climate that is unprecedented in geological history, apart from a massive meteor event, it just hasn't happened so fast!

So the models are bogus, we have never had an atmospheric forcing happen so fast that the ocean's Sea Surface Temps couldn't warm fast enough. we simply don't know what the clouds and the atmospheric circulations are going to do.

But we have an idea with the outrageous mid-latitude moisture moving regularly up into the arctic since the last El Nino and China cut it's sulfur dioxide emissions by 13%.

And NO it won't be the 'end of civilization' it will be a powerful activating event that will polarize society into mobilizing. Working together to end the fossil fuel era using techniques and economic models that have not been embraced since the beginning of World War II. (I am talking about global production of renewable energy and transformations of our agriculture, transportation and industrial activities). It will take a massive amount of work and effort but it will also produce a much leaner, self-sufficienct, and environmentally conscious global society, with limited economic disparity and massive increases in total resources. In the end we will find out that it was really the greed of a few powerful men that had enslaved the whole world.

We will be back to 300 PPMv CO2 by 2075.

Elisee Reclus

Joe_nilo

You're quire right, Sandy was a very large storm as far as geographical size is concerned, but I was referring to its status as a Category 3. That's a big storm, with winds over 100 MPH, but still not as big as a Cat 5.

Besides, as I'm sure you're aware, the strongest winds in a storm are concentrated in a small area right near the eye, and are not necessarily dependent on the overall dimensions of the weather system.

Man, picky picky. I can't sneak anything past you guys. :)

As far as Jai Mitchell's comment:

It is ALWAYS the greed of a few powerful men that enslaves the world. Same as it ever was.

Rob Dekker

No offense to Pyotr, who feels safe at 2 meters above sea level in SE Florida, while Katrina-style 15 feet storm surge reached 10 miles inland, but this report suggests that Miami is faced with a whopping $3.5 Trillion loss in assets by 2070 due to sea level rise :
http://therealdeal.com/miami/2016/08/16/miami-faces-3-5t-loss-highest-risk-of-sea-level-rise-among-all-coastal-cities-report
That's just one city, folks...

Jim Hunt

Jai - I too heard that podcast, and I also saw the way Vid was misreprenting Neven in public. I directed his attention here:

https://en.m.wikipedia.org/wiki/Defamation#Norway

What action would you recommend be taken against someone who ignores repeated warnings, whether you subscribe to the same beliefs or not?

Sam

Jai,

I would love to believe that "...it will be a powerful activating event that will polarize society into mobilizing. Working together to end the fossil fuel era using techniques and economic models that have not been embraced since the beginning of World War II." etc. and "We will be back to 300 PPMv CO2 by 2075."

I don't believe even for a moment that either of these can occur.

The first will in all probability be ruled out by ignorant self interest that will deny reality right to the last. The second will in all probability be ruled out for the same reason. These require massive sacrifice on everyone's part and a move away from our current societal systems that price everything. That's just not going to happen.

Like Vidaloo and others, I believe that this disruption event is likely to happen. What I am less convinced about is the timing. It seems likely that the change to ice free conditions will be the point of transition, that the warming of the Arctic thereafter will be much more rapid and will lead to the destabilization.

This is classic high school science. Ice in a glass of water greatly stabilizes the temperature of the water. Adding heat to the glass quickly translates into melting ice with little temperature change. But once the ice is gone - hang on to your hat.

Sam

NeilT

Jai, I liked a lot of what Vid took time to post as Neven did. But what I did not like was the black and white nature of what was being presented. The more you asked questions the more blunt and combative the responses.

We see that elsewhere and it only takes a few people to start backing Vid and it them becomes less of a blog and more of a monologue to the beliefs of a few people.

Neven does an excellent job of ensuring that this blog does not get taken over by evangelists of either persuasion and it is done in a pleasant and well mannered way.

As to the "we'll all pull together" bit? Sorry my faith is lacking.

Let's ignore the Trump phenomena for a moment and look into the psyche of people in the UK. In our EU debate people were seriously talking about the benefit of cheap holidays to the sun in Spain in the context of the future economy, wealth, wellbeing and structure of society in the UK.

Worse, people actually voted based upon whether they could go on holiday without having to get their passport stamped....

You think these kind of people are going to get together and engage when they are not knee deep in water with storms taking their homes away and no food to eat?

I like your faith. But I believe we'll get back to 300ppm in about 20,000 years time.

AGW will cause famine and food riots and regime change in the most vulnerable places in the world. Some of those places have nuclear weapons.

We're quite capable of wiping ourselves off the face of the earth without the climate. However the climate may be the taper lighting the blue touch paper.

Honestly, we're too stupid as a species to see the road in front of our feet. In general the human race has become a species of gawping tourists on the bus to hell. Nice scenery on the way but just a bit hotter than anticipated when they get there.

NeilT

Generally, Katrina had an open sea storm surge of 15 feet. No matter where it landed it would have done serious damage.

However where it did make landfall with the surge, it reached over 40 fee in the highest places. Due mainly to the topography of the land rather than the size of the surge. But it was that huge surge which made the records.

Katrina was special because it was a Cat5 less than 24 hours before it made landfall. The hurricane may have dropped to Cat3 by the time it hit land, but the storm surge does not dissipate that fast and it hit with a surge of a Cat5.

Sandy was of a different kind. So huge in coverage that it hit with the surge of a cat3 hurricane and it was so huge that the eyewall of the hurricane was only degraded as it made landfall and ran up the coast, not destroyed. Allowing Sandy to keep going and create total havoc.

As far as I can determine, these are the kinds of changes which AGW is forcing on Hurricanes and they don't fall into normal models.

Hence normal "I should be protected" may not always work in the future.

Food for thought.

Joe_nilo

Elisee Reclus

We're not being picky when correcting your misstatements. While there may be a lot of speculation on this board, it's generally based on facts and we like to stick to them as much as possible.

I say "we", but I'm a longtime lurker and I generally don't post. However, I've seen the tone and tenor here seems to have changed lately. Disagreements have turned to rants and ad hominem attacks. I find this distressing.

Vidaloo went off the rails and Neven was right to ban him. Insisting your personal speculation to be the only correct interpretation of sea ice data is not in the spirit of this board.

I hope we can get back to talking about the Arctic sea ice soon.

Jai Mitchell

I am not criticizing anyone. I like Vid for his passion and his truth. Even though his technical analysis may not be true, the 'meta-message' is. This message that we really don't have any more time left. none at all. needs to be communicated in a way that punctures our collective sensibilities and the warm, fuzzy pretense that we can 'free-market' our way out of this collective existential crisis. The reason is that, we are already over the hump and on a rapidly accelerating downward trajectory, but some people (at the back of the roller coaster) are simply feeling more wind in their hair.

I am not familiar with Norway's defamation laws and don't think it matters (at all). He can be really meanspirited and confrontational and accusatory and doesn't take criticism lightly and believes that we are all blindly rushing to our doom, and he may be right so I give him that. I just said it was a bummer that he got himself banned for being a jerk to neven ;-).

We have an amazing potential for alleviating these problems in our society. I sincerely believe that, when we realize that the scientific models are (horrifically) underestimating climate impacts that we will begin to demand the change that we need. There is amazing potential for both the societal demand response and the technical potential for all of these technologies, including the deposition of liquid CO2 into basalt structures and regenerative agriculture to restore climate balance.

But Vid is right in that the ice will go away very very soon and that the resulting temperature regime and, apparently, atmospheric circulation regime shifts will be dramatic and, likely, catastrophic. He may be right that a year-round ice free state is possible in the next 15 years. To me that is conjecture and doesn't matter as a summer ice free state in the next 5 is already 50 years ahead of most models.

I would like to see a public push for the selection of lead authors for the 'mea culpa' that will serve as the forward to the IPCC AR6. In view of the collective AR4 Nobel Prize, it is only right.

NeilT

Jai, I believe Vid got himself banned for taking Neven out of context on Twitter to try and push his own agenda. I wouldn't tolerate it either.

On the "ability" v "action" arena, your faith in human nature is way greater than mine. I still run into people who think that it's all a matter of opinion and why should be do something about it till it's categorically proven (i.e. their feet are 18 inches deep in water). Or, to put it another way, way, way, way too late to do anything constructive at all.

Back to the ice.

I've noticed that the Pacific side has an absolutely mulish tendency, this year, to resist re-freeze. This is interesting because looking at Chartic 2016 will come in below 2010 for the end of year extent.

This is important because when playing with Chartic I noticed that in the 1980 - 2003 record there was a consistent drop in area at year end. But from 2004 onwards every year, except 2010, came in at almost exactly the same extent at year end.

If 2016 comes in under 2010 for extent, then it could usher in a new reducing bias which will tighten the spiral even tighter. Also if, as I believe, 2017 is going to be another 2007 type year, then 2017 will continue that downward trend.

A lot of interesting viewing over the next year or so.

AnotherJourneybyTrain

dmi temp is being stubborn again(Tues dec 20): any ideas why?

Jai Mitchell

The numerical value of extent right now has very little correlation to ice conditions in 2010. The first 5 months of abnormally warm arctic temps led to the horrible ice conditions that are currently present. There is a compounding effect now in play with decreased volume formation, increased ice mobility, subsurface mixing and underice melt. Increased storms and latent heat intrusion in the mid-lower troposphere, much of it directly translating from the warm-pool in the Gulf of Mexico directly up and past Iceland into the CAB. It is happening on the Pacific side as well. We simply do not have the models down for rapidly increasing ocean SST anomalies gaining so much heat that the rate of expansion to the deeper water column cannot keep up. The only other direction for this heat is upwards, into the atmosphere and that is what we are seeing now. The only question is, how much is the Tropospheric aerosol loading impacting this 0-700m OHC accummulation, and, what will be the impacts of a rapid reduction of SO2 emissions under climate mitigation scenarios on the meridional transport of water vapor (and heat) from the tropics into the >40'N (and higher!) latitudes.

If the indications are right, megadroughts, atmospheric rivers, massive cut-off, stationary lows (with associated inundations) and rapid Arctic sea ice deterioration will occur in timescales that are significantly shorter than the current working models.

Jim Hunt

A.N.Other - Try taking a look at the temperature anomaly map:

http://GreatWhiteCon.info/resources/arctic-sea-ice-graphs/#CCITemp

Can you "read" the isobars?

NeilT

Jai I wasn't saying 2016 was like 2010. In fact I believe it will come below.

What I was saying is that from 2004 onwards there seemed to have been a trend set as to the extent value for year end. 2010 was an outlier to this.

Clearly 2016 is massively different from 2010 and I was musing that it might herald a shift from this post 2004 trend into a new reduction trend as was seen before 2004.

So, in short, less extent and even less next year due to all the huge changes we are seeing right now.

Susan Anderson

Elisee, Peter Kropotkin (and there's a namesake for the books!), or whoever you are, sorry, your posts must have been stuck in moderation when I made that remark, and your further biographical details and remarks would have prevented me from saying that. But I was indeed talking about Neven and the long-time people who have labored tirelessly to observe and improve on observations of developments in the Arctic here. Yes, there are a few people who argue with each other, but overall the feeling has been of collaboration and respect.

Isn't Florida porous?

WRT Sandy, I lived through it in New Jersey (my mother was on life support) and the power was out five days (we were lucky to have a town who knew about her and made sure we got help early). Many people were out of power for two to four weeks, and some people in Manhattan never got their telephones back. Some people in highrises had no water for a very long time.

We were lucky to have Obama in charge, and unlucky to have greedy Christie steering recovery funds to developers instead of victims. Obama has made a real difference to the effectiveness of FEMA and relief efforts during his tenure, in his quite and efficient way. Trump et al. will do their best to take that apart for loot; that's what they do.

The storm itself was an exemplar of climate disruption in several ways: it was late in the season, it was a hybrid storm that married a tropical storm with a "northeaster" (a New England phenomenon, which normally lasts over two days), and there was the blocking high at Greenland that turned it. It was huge (about a thousand miles across) and it lasted a very long time. As we waited for it to come, the debris went from twigs to branches to trees.

Jeff Kuper

Back to the sea ice...

It would seem that in the last 4 weeks we have had quite significant sea ice extent growth in the Arctic and we have almost caught up with 2012 levels.

However, according to my amateurish analysis I believe that the sea ice growth rate is going to be significantly lower in the upcoming weeks. Based on NSIDC, the likely sources for ice growth is in the Bering, Chukchi, Kara and Barents. However, the SST anomalies would seem to preclude much of a possibility of rapid sea ice growth. In addition, when comparing NSIDC outputs vs a "visual" inspection of the sea ice through arctic.io it would seem that ice is fairly sparse in the Bering and Kara Seas and minimally climbs over the 15% threshold. So while NSIDC shows much of the Bering or Kara covered, it is quite thin and sparse. So the growth in those areas are already accounted for in NSIDC figures.

For those reasons, I would expect the slope of the ice extent plot to decrease in the near future.

Thoughts? Contrary pieces of evidence?

AnotherJourneybyTrain

https://www.britannica.com/science/climate-meteorology/Scale-classes#ref293133

handy resource, for example:

Another subset of katabatic flow, called foehn winds (also known as chinook winds east of the Rocky Mountains and as Santa Ana winds in southern California), is induced by adiabatic temperature changes occurring as air flows over a mountain. Adiabatic temperature changes are those that occur without the addition or subtraction of heat; they occur in the atmosphere when bundles of air are moved vertically. When air is lifted, it enters a region of lower pressure and expands. This expansion is accompanied by a reduction of temperature (adiabatic cooling). When air subsides, it contracts and experiences adiabatic warming. As air ascends on the windward side of the mountain, its cooling rate may be moderated by heat that is released during the formation of precipitation. However, having lost much of its moisture, the descending air on the leeward side of the mountain adiabatically warms faster than it was cooled on the windward ascent. Thus, the effect of this wind, if it reaches the surface, is to produce warm, dry conditions. Usually, such winds are gentle and produce a slow warming. On occasion, however, foehn winds may exceed 185 kilometres (115 miles) per hour and produce air-temperature increases of tens of degrees (sometimes more than 20 °C [36 °F]) within only a few hours.

(Over on the forum someone mentioned foehn winds on the antarctic peninsula so I googled it and found a great yet easy to read resource!)

[Edit Neven: AIG, the same rules apply here as on the Forum. Stay on-topic as much as you can, and don't ask too many questions]

Elisee Reclus

The time is with the month of winter solstice
When the change is due to come
Thunder in the Earth, the course of Heaven
Things cannot be destroyed once and for all

--Pink Floyd (in Chapter 24, The Piper at the Gates of Dawn, 1967)

Today, the solar declination reaches -23d 26'. From today onward, solar insolation can only increase, although thermal inertia will keep temperatures dropping for a while yet and the ice extent will continue its seasonal increase.

Its true, sea ice extent is rapidly rising to its 2012 levels for this time of year, but the fact remains that today it is lower than it has ever been on the solstice since we began satellite monitoring. But we also know winter extents are not good predictors of spring minima, so the significance of this statistic will only become clear in hindsight.

All we know for certain is that for the last 37 years the linear regression of the satellite SIE data is dropping precipitously for the average of every month, but is steepest for Septembers. That is undeniable evidence. Everything else is just thoughts. Including this post.

Still, the human perceptual and interpretive apparatus has evolved an uncanny ability to detect patterns which cannot be justified logically; much of our mental processing occurs subconsciously. It is far from infallible, it often leads us astray, but in the absence of data it is all we have and more often than not our informed intuitions are valid.

Intelligence can be defined as the ability to make the correct evaluations even when data is scarce, at least, most of the time. The problem arises when we try to justify those subjective assessments logically to others.

Elisee Reclus

Susan--

Yes, Florida is porous. Bot vertically (its mostly alternating layers of limestone and sand) and horizontally (flat, and cris-crossed by canals designed to destroy wetlands for development. Florida is a warning of what happens when we let real estate moguls drain swamps.

John Christensen

Coming SSW event?

I noticed on the DMI forecast that temps just north of the CAA may dip below -40C on Jan. 7th.

As such a low temperature is rather unusual for recent years, I was wondering if this might be related to a sudden stratospheric warming event?

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