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Messages - gerontocrat

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Arctic sea ice / Re: The 2019 melting season
« on: June 16, 2019, 05:11:54 PM »
University of Bremen link still not operational.

IMO this is by far the best substitute for what you were looking for and for several reasons

try out the various features including large and very large image.

AFAIK the source is the same as well, hence no significant change of result between platforms to be expected

Arctic sea ice / Re: AMSR2 Snow & Ice Volume/Thickness
« on: June 02, 2019, 01:01:30 AM »
Volume continued below the mean, but thickness went up at the end of the month. It looks like the Beaufort gyre compacted sea ice against eastern Siberia and Hudson Bay ice was compacted against the southern coast.

Full size images and May animation at:

Policy and solutions / Re: Nuclear Power
« on: May 30, 2019, 02:35:04 PM »
New nuclear plants should not be built.  Existing nuclear plants should be maintained as much as possible until most FF plants are retired.

Arctic sea ice / Re: AMSR2 Snow & Ice Volume/Thickness
« on: May 03, 2019, 11:29:48 AM »
Another month of low overall gain, but above average thickness.

Full size images and April animation at:

Science / Re: Underground temperatures trends
« on: April 02, 2019, 08:52:07 PM »
A slippery slope: How climate change is reshaping the Arctic landscape article about study by Antoni Lewkowicz, University of Ottawa, published in Nature Communications
Increasing ground temperatures in the Arctic are indicators of global climate change, but until recently, areas of cold permafrost were thought to be relatively immune to severe impacts. A new study ... shows that areas of cold permafrost can be vulnerable to rising summer temperatures.

… recorded an astounding sixty-fold increase in the number retrogressive thaw slumps—landslides caused by the melting of the ice in the permafrost—on Banks Island over the past three decades.

Arctic sea ice / Re: Arctic Image of the Day
« on: March 23, 2019, 09:42:14 AM »
A pod of narwhal in the Arctic

Antarctica / Re: PIG has calved
« on: January 26, 2019, 05:56:57 PM »
Pine Island Glacier: 18 months of flow and calving

Antarctica / Re: Sea Ice Extent around Antarctica
« on: January 01, 2019, 06:36:02 AM »
It seems that the climate scientists have not come up with a generally accepted reason for this third year of much lower Antarctic sea ice extent, though there has been much speculation about this in this thread

The conventional wisdom (not just from Hansen by any means) is that as Antarctic ice sheet melt increases, additional fresh and cold water should encourage an increase in sea ice. The last 3 years data is in contradiction to that. I can find no science paper on this contradiction at all. When the GRACE mass data re-starts (from early 2019), perhaps this will tell us the extent to which the rate of Antarctic ice sheet mass loss has increased or decreased over the last 3 years.

Those still alive will see in another decade or two. Meanwhile, adding Hansen's latest mailing.
As yet the rate of freshwater injection onto the Southern Ocean may not have yet reached a level large enough to counter the loss of sea ice due to global warming, as judged from the large sea ice area reduction that has accompanied the warming of the past few years.

 Nevertheless, it is clear that amplifying feedbacks will produce increasingly rapid sea level rise if fossil fuel emissions and global temperatures continue to increase unabated. Even in the case of slowly changing paleoclimate forcings, ice sheet disintegration on a number of occasions achieved a rate that produced meter and multi-meter sea level rise in a century, confirming the existence and the potential large magnitude of amplifying feedbacks. Once the global warming effect on ice sheets is sufficient to strongly spur the amplifying feedbacks, we would expect the rate of mass loss by the ice sheets and the rate of sea level rise to grow nonlinearly, at a faster and faster rate.

 A capable means of assessing possible Greenland and Antarctic ice sheet mass loss became available with the first precise monitoring of Earth’s gravitational field from a satellite (Fig. 17). Early results from the gravity satellite showed shockingly rapid growth of the mass loss rates for both the Greenland and Antarctic ice sheets, for Greenland through 2012 and for Antarctica through 2015 (Fig. 17). Doubling times for mass loss rates were only of the order of a decade for both Greenland and Antarctica. However, in Greenland in 2013 and Antarctica in 2016 the rapid growth of mass loss was interrupted by a negative feedback: increased precipitation (snowfall).

 Decreased summer melt and increased snowfall over Greenland were associated with a change of summer weather patterns. The 2012 summer was characterized by sunny weather and a steady stream of warm air streaming from the south over Greenland, but subsequent summers have had a high proportion of cloudy days with moist marine air. Increased snowfall over Antarctica in the past two years was associated with reduced sea ice in the adjacent Southern Ocean, which coincided with rapid global warming during that period. The magnitude of the sea ice loss may have been related to the coincident strong El Niño. On the longer run, it has been predicted that increasing ice discharge from Antarctica, especially in the Western Hemisphere from the Ross to Weddell seas, will tend to cause an increase of sea ice cover, altering the precipitation feedback (see Fig. 16).

The rest / Re: Unsorted
« on: December 14, 2018, 10:48:08 AM »
When you mentioned Carson in February I downloaded it, no library nearby.

Permafrost / Re: Arctic Methane Release
« on: November 22, 2018, 06:02:17 AM »
During the Sangamon interglacial, rivers flowed north into the Arctic dumping organic material onto the shelves. At the start of the last glacial, ice dams formed, forcing the rivers to flow south. The sea level in the Arctic dropped exposing the shelves. The shelves remained exposed throughout the last glacial, and as the Holocene began, glacial meltwater turned the shelves first into a wetland, then with the rise of sea level, the shelves were submerged.

The permafrost that formed throughout the last glacial began to degrade even before the shelves were submerged as thermokarst lakes and rivers formed taliks. Much like is happening to terrestrial permafrost today.

Once submerged, the new warmer subsea environment, the salinity (think what happens when you put salt on a frozen doorstep), and geothermal flux from below, worked over the last 8,000 years to degrade the permafrost to the point that it now is pourous, and even totally gone in places, over an area of 2 million sq km.

Much of the methane hydrates that formed over the last 100,000 years since the Sangamon, dissociated, leaving a large reservoir of free methane gas under pressure, prevented from releasing only by the layer of permafrost which until now had acted as a cap.

Since the shelf is on average about 50 meters deep, any methane released does not interact with the water column, but releases directly to the atmosphere.

This is the end result of a geological process that has been going on for thousands of years and is a part of a natural cycle.

Over the last decade, the size of the areas releasing methane has increased and the amount being released has accelerated.

The release of just 1% of the available free methane on the shelf is enough to cause catastrophic warming.

Since there is no way to refreeze the degrading permafrost cap, the methane release is inevitable.  There is no way to shut it off.  And the methane will continue to release until there is no more left to release.   

Whoever is questioning the decades of observations and research conducted by Semiletov and Shakhova haven't got a clue.  Semiletov is the head of the far eastern branch of the Russian Academy of Sciences.  Dozens of scientists have participated in this research.   

If you have research papers providing rebuttal to their work, post it.

Just saying "some people say" doesn't cut it around here.
Here, we present research papers and discuss them.         


Arctic sea ice / Re: The 2018-2019 freezing season
« on: September 19, 2018, 03:34:20 PM »
In the freezer it goes, and I'll pull it out again once JAXA goes 25K above the preliminary minimum reached yesterday. Traditions are there to be respected.  ;)

Walking the walk / Well done but it's not over.
« on: September 08, 2018, 07:36:49 AM »
For my t-shirt hobby (it's far away from a business, I was looking for ideas to create a T-shirt about non violence.

I first arrived on the web site of the King Center that have an interesting glossary where I kept 2 key words :
  • Ahisma, which means more or less non violence (« a » for non and « hisma » for violence)
  • Satyagraha which is best defined by a quote “Satyagraha is literally holding on to Truth and it means, therefore, Truth-force. Truth is soul or spirit. It is, therefore, known as soul-force.” M. K. Gandhi

When googling both words, I followed different links and had the feeling that in Gandhi’s concept, holding on to the truth seems more important than non violence. Non violence would be to be the way to act, but holding the truth is the corner stone that is required if non violence is to be used.

About satyagraha, I found 2 interesting links,

Here are some quotes

"Gandhi believed in the scientific method of:
  • accumulation and presentation of evidence;
  • review of the logical processes employed for arriving at a conclusion;
  • joint examination of these processes and evidence;
  • replaying that tape by which one has arrived at a conclusion so that one may detect the point where divergence commenced;
  • investigating whether the refusal to see evidence and logic is the result of ego-centric attitudes and perceptions and if it is found that this is what leads to intransigence, then
    divesting oneself of ego-based considerations that have only a limited place within the unalterable paradigm of interdependence that rules humanity;
  • reassuring the “adversary” that the effort is not to deny his needs and interests, while promoting introspection in the adversary through love and the readiness to suffer (voluntary suffering).

In spite of all these efforts on one’s part, one may not be able to dissolve intransigence on the other side. Such a situation where all efforts of persuasion seem to have failed would demand Direct Action."

"Nonviolent non-cooperation and Civil Disobedience can be effective only if operational conditions are controlled to prevent the outbreak of violence, and loss of control by the leadership of a struggle. Gandhi firmly believed that two antagonistic forces could not work to supplement each other. »

I just wanted to say that it looks like we are doing a good job, that it is important to go forward. I feel that always more people are aware that things have to change. I believe that we are right, that we have to hold to it and that, walking the walk, we are somehow doing a direct action to change the game. Let's continue.

Arctic sea ice / Re: 2018 sea ice area and extent data
« on: July 15, 2018, 11:47:14 AM »
Thanks Geron!

They also have a great 10 day ice concentration map that I like to keep tabs on.

Click image to play

Arctic sea ice / Re: How soon could we go ice free?
« on: June 18, 2018, 12:25:28 PM »
I think Figure 1 from Tietsche et al 2011 is important.

This shows two things - firstly, the general shape of the (modelled) decline in Arctic ice over the coming decades, and secondly the time taken to recover from extreme events such as the summers of 2007 and 2012.

For the latter, the conclusion is quite simple - the Arctic has a "memory" of about two years, and so any major excursion will bounce back to the long-term trendline within a couple of years.  They only modelled downward excursions, but my guess is that it holds the other way too - even if by chance we have a particularly good year for ice retention, it'll be gone in another couple of years.  The paper discusses the mechanisms for this, but fundamentally it's quite simple - if you have a massive loss of ice one autumn, that means a correspondingly massive extra heat loss in the following winter.  By the end of spring, first year ice has grown back. A low summer minimum has very little effect on the following maximum.  This is believable, and we've seen it after every major loss year for more than a decade now.

For the longer term decline, look at the shape of the curve.  Note how it's staggered and stepped.  This reflects the shape of the Arctic ice basin. There are shallow seas around the edge, and a deep central portion that covers about 5 million square km. So, as ice loss progresses, there's an initial period of rapid decline that plateaus at around 4.5 to 5 million until about 2020.  That's exactly where we are now, in that plateau, where the summer minimum roughly covers the deep parts of the Arctic Ocean but the peripheral seas melt out each summer. Subsequently, there's another period of rapid decline that plateaus again at 1.5-2 million.  This is the "remnant above Greenland" stage.  The final collapse comes after that.

The shape looks entirely plausible to me, all that we need to work out is the scaling on the X axis, and to be honest I'd be surprised if they're far off. Right now we're on the verge of the second period of decline - but it'll plateau again in another couple of decades, probably before hitting the "ice free" threshold of 1 million.

It may be we need to squash the X axis up by 10% or so to fit reality - someone with more time than I can probably make an overlay - but it's really not far off.

Arctic sea ice / Re: 2018 sea ice area and extent data
« on: June 16, 2018, 05:51:27 AM »

June 15th, 2018: 10,236,731 km2, a drop of -81,224 km2.
2018 is the fifth lowest on record.

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