We need to be alert to a metastasis of consequences to humankind and all else, as Arctic ice melt proceeds.
Cross-post of comment I put on Joe Romm's blog.
The multi-year loss of old ice through the Fram Strait should get LOTS more attention.
Research papers in the past twenty years on thermohaline circulation
show the importance of a seasonal flow of freshwater from melting ice in
maintaining global ocean currents.
The gradual exhaustion of multi-year ice has delayed a metastasis of
consequences, of which disrupted ocean currents would be one of those to
have a big effect on humans.
It is boggling to imagine what disrupted currents could do, in
conjunction with the effects on Jet Stream and mid-latitude weather as
already described by Dr. Jennifer Francis.
Please also check my earlier post at Planting Ahead about thermohaline circulation.
Wednesday, September 26, 2012
Tuesday, September 25, 2012
"Climate change happens" vs. "is happening"
Have you not heard, "climate change is happening," spoken as a version of "duh?"
Now I know, and perhaps you know, that the Arctic sea ice summer extent declined sharply, glaciers melted back, mosquitoes live at higher altitude than in previous generations, animal and plant species have moved, and global temperature measurement has revealed major changes, including accumulation of heat in the oceans.
Mouthful of examples there, yet only a bite.
So, yes, climate change is happening, all the time 24/7, or 365/24/7.
But can we assume that your listener already has seen the evidence, and agrees with your conclusion? If your listener turns around in their air-conditioned office, orders lunch, and gazes at a pretty park across the street, in that moment does he or she see any sign that climate change, indeed, "is happening?" Unlikely.
Does your listener understand that the price of ingredients in the lunch was affected by global supply, in turn affected by climate? Or the hours of use of air-conditioning? Or the plant species in the park? Or the odds of severe weather? Also unlikely.
For many humans, "is happening" refers to a present moment of personal awareness; "It's happening, baby."
I'm leaning towards another phrase with the word "happens," and say,
Climate change happens.
Crop failure happens. Floods happen. Refugees happen.
We have moments when we notice.
In looking ahead, or planting ahead, let's be real about what has happened to date, and take into account both shifted conditions of heat, moisture, insects, etcetera and a shifted level of uncertainty.
In short, planning for uncertainty, as well as new certainty.
Now I know, and perhaps you know, that the Arctic sea ice summer extent declined sharply, glaciers melted back, mosquitoes live at higher altitude than in previous generations, animal and plant species have moved, and global temperature measurement has revealed major changes, including accumulation of heat in the oceans.
Mouthful of examples there, yet only a bite.
So, yes, climate change is happening, all the time 24/7, or 365/24/7.
But can we assume that your listener already has seen the evidence, and agrees with your conclusion? If your listener turns around in their air-conditioned office, orders lunch, and gazes at a pretty park across the street, in that moment does he or she see any sign that climate change, indeed, "is happening?" Unlikely.
Does your listener understand that the price of ingredients in the lunch was affected by global supply, in turn affected by climate? Or the hours of use of air-conditioning? Or the plant species in the park? Or the odds of severe weather? Also unlikely.
For many humans, "is happening" refers to a present moment of personal awareness; "It's happening, baby."
I'm leaning towards another phrase with the word "happens," and say,
Climate change happens.
Crop failure happens. Floods happen. Refugees happen.
We have moments when we notice.
In looking ahead, or planting ahead, let's be real about what has happened to date, and take into account both shifted conditions of heat, moisture, insects, etcetera and a shifted level of uncertainty.
In short, planning for uncertainty, as well as new certainty.
Saturday, September 22, 2012
math while angry, and new vocabulary about the brain
Every now and then I have the embarrassing experience of making a public correction on an arithmetic calculation.
I'm relieved if I catch it before someone else does.
One such event today reminds me yet again that math while angry is often flawed.
It is no surprise that hormones that could make me kick butt get in the way of a tranquil double check of conversion factors and decimal places. But when I am angry, it usurps other forms of decision making. Duh.
Time to take deep breaths, and oxygenate not only that darling frontal cortex, but also parietal cortex and particularly the intraparietal sulcus, thought to be essential to calculation. And hope the supramarginal gyrus isn't subvocalizing something completely irrelevant, like, @#^*&!!
Fortunately neuroscientists are looking at these matters. It is encouraging to see the many abstracts that come up in a PubMed search.
I'm relieved if I catch it before someone else does.
One such event today reminds me yet again that math while angry is often flawed.
It is no surprise that hormones that could make me kick butt get in the way of a tranquil double check of conversion factors and decimal places. But when I am angry, it usurps other forms of decision making. Duh.
Time to take deep breaths, and oxygenate not only that darling frontal cortex, but also parietal cortex and particularly the intraparietal sulcus, thought to be essential to calculation. And hope the supramarginal gyrus isn't subvocalizing something completely irrelevant, like, @#^*&!!
Fortunately neuroscientists are looking at these matters. It is encouraging to see the many abstracts that come up in a PubMed search.
Thursday, September 20, 2012
thermohaline circulation and Arctic ice, updated
Take a look at the diminished flow of multi-year sea ice through the Fram Strait as shown in the Yale video. The video portion on the multi-year ice loss is narrated by Dr. Jennifer Francis of Rutgers, yet I would like to have the original source of the data, most likely the NISDC. [This video is also imbedded in a blog by Joe Romm on the Arctic Ice Death Spiral.] The scientists in the video point to the "positive feedback" of an open water Arctic Ocean in summer, the open water would absorb the sun's energy and accumulate heat during the days of nearly twenty-four hours of sunlight. The white ice cap that we are losing so abruptly had reflected light back into space; the dark open water does little of that. That's an important point, within the scope of scientific inference.
We need to connect more, and the scientific "dots" already exist.
What I want us to understand - in short - is that an ice-free Arctic could affect "the ability of the ocean’s thermohaline circulation to assume more than one mode of operation (Broecker)" and "The strength of the thermohaline cell will be shown to depend on the amount of sea ice transported from the Arctic to the Greenland Sea and further to the subpolar gyre (Mauritzen, C. and S. Häkkinen)."
The thermohaline circulation is the global movement of ocean currents.
Arctic sea ice reaching the Greenland Sea has a major effect on thermohaline circulation.
Without sea ice, we are indeed in uncharted waters.
---------------------------------------------------------------------
Some sources:
Mauritzen, C. and S. Häkkinen (1997), Influence of sea ice on the thermohaline circulation in the Arctic‐North Atlantic Ocean, Geophys. Res. Lett., 24(24), 3257–3260, doi:10.1029/97GL03192.
Abstract:
A fully prognostic coupled ocean‐ice model is used to study the sensitivity of the overturning cell of the Arctic‐North‐Atlantic system to sea ice forcing. The strength of the thermohaline cell will be shown to depend on the amount of sea ice transported from the Arctic to the Greenland Sea and further to the subpolar gyre. The model produces a 2–3 Sv increase of the meridional circulation cell at 25N (at the simulation year 15) corresponding to a decrease of 800 km³ in the sea ice export from the Arctic. Previous modeling studies suggest that interannual and decadal variability in sea ice export of this magnitude is realistic, implying that sea ice induced variability in the overturning cell can reach 5–6 Sv from peak to peak.
Science 28 November 1997:
Vol. 278 no. 5343 pp. 1582-1588
DOI: 10.1126/science.278.5343.1582
Thermohaline Circulation, the Achilles Heel of Our Climate System: Will Man-Made CO2 Upset the Current Balance?
Wallace S. Broecker
The author is at The Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA.
Abstract
During the last glacial period, Earth’s climate underwent frequent large and abrupt global changes. This behavior appears to reflect the ability of the ocean’s thermohaline circulation to assume more than one mode of operation. The record in ancient sedimentary rocks suggests that similar abrupt changes plagued the Earth at other times. The trigger mechanism for these reorganizations may have been the antiphasing of polar insolation associated with orbital cycles. Were the ongoing increase in atmospheric CO2 levels to trigger another such reorganization, it would be bad news for a world striving to feed 11 to 16 billion people.
We need to connect more, and the scientific "dots" already exist.
What I want us to understand - in short - is that an ice-free Arctic could affect "the ability of the ocean’s thermohaline circulation to assume more than one mode of operation (Broecker)" and "The strength of the thermohaline cell will be shown to depend on the amount of sea ice transported from the Arctic to the Greenland Sea and further to the subpolar gyre (Mauritzen, C. and S. Häkkinen)."
The thermohaline circulation is the global movement of ocean currents.
Arctic sea ice reaching the Greenland Sea has a major effect on thermohaline circulation.
Without sea ice, we are indeed in uncharted waters.
---------------------------------------------------------------------
Some sources:
Mauritzen, C. and S. Häkkinen (1997), Influence of sea ice on the thermohaline circulation in the Arctic‐North Atlantic Ocean, Geophys. Res. Lett., 24(24), 3257–3260, doi:10.1029/97GL03192.
Abstract:
A fully prognostic coupled ocean‐ice model is used to study the sensitivity of the overturning cell of the Arctic‐North‐Atlantic system to sea ice forcing. The strength of the thermohaline cell will be shown to depend on the amount of sea ice transported from the Arctic to the Greenland Sea and further to the subpolar gyre. The model produces a 2–3 Sv increase of the meridional circulation cell at 25N (at the simulation year 15) corresponding to a decrease of 800 km³ in the sea ice export from the Arctic. Previous modeling studies suggest that interannual and decadal variability in sea ice export of this magnitude is realistic, implying that sea ice induced variability in the overturning cell can reach 5–6 Sv from peak to peak.
Science 28 November 1997:
Vol. 278 no. 5343 pp. 1582-1588
DOI: 10.1126/science.278.5343.1582
Thermohaline Circulation, the Achilles Heel of Our Climate System: Will Man-Made CO2 Upset the Current Balance?
Wallace S. Broecker
The author is at The Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA.
Abstract
During the last glacial period, Earth’s climate underwent frequent large and abrupt global changes. This behavior appears to reflect the ability of the ocean’s thermohaline circulation to assume more than one mode of operation. The record in ancient sedimentary rocks suggests that similar abrupt changes plagued the Earth at other times. The trigger mechanism for these reorganizations may have been the antiphasing of polar insolation associated with orbital cycles. Were the ongoing increase in atmospheric CO2 levels to trigger another such reorganization, it would be bad news for a world striving to feed 11 to 16 billion people.
lost in moderation
The longer that one of my geekier posts stays "in moderation" on another blog, the more the term "in moderation" develops new facets.
Was my post immoderate in its sheer geekiness? Yeah, probably way too geeky.
Also standard filters kick out posts over a certain length and hold them for review, as well.
And, of course, after the tedious process of finding and cleaning up the citations, did I forget to click on agreeing to the terms of the website? Could have happened.
I'll post the geek post on my blog..
Was my post immoderate in its sheer geekiness? Yeah, probably way too geeky.
Also standard filters kick out posts over a certain length and hold them for review, as well.
And, of course, after the tedious process of finding and cleaning up the citations, did I forget to click on agreeing to the terms of the website? Could have happened.
I'll post the geek post on my blog..
Tuesday, September 18, 2012
2016 hot iced tea and reaping the whirlwind
On a humid summer's day, when the last sliver of ice melts in the glass of iced tea, it's time to ask for a new ice cube, or chug down the tea before it rapidly heats up. (See enthalpy of fusion). These are not options when it is an ocean that is about lose its last ice chips and heat up.
In the Arctic, the summer sea ice has kept the Arctic Ocean cool. Recently Professor Peter Wadhams of Cambridge, expert on Arctic ice, has alerted the British newspaper, the Guardian, to a revised expectation that the summer Arctic sea ice is likely to be gone by 2016.
The summer sea ice area has shrunk from year to year, in what has been called a death spiral as vividly illustrated by Neven of the Arctic Sea Ice Blog. In September 2012 the sea ice has reached the lowest areal extent since records have been kept.
A correlation between declining Arctic sea ice and extreme weather has emerged. The altered Arctic weather loosens up the northern Jet Stream which instead of streaking around the high latitudes upper mid-latitudes, slows down and develops what look like the meanders of an old river. These loops in the Jet Stream act as blocking patterns that hold weather in place for longer periods of time, giving us heatwaves and super storms in the mid-latitudes, with the oddities of colder days further south and other new extremes. Dr Jennifer A. Francis of Rutgers has been showing the data on the relationship, of which a 16 minute video is a good introduction, hang in there with it and look at the diagrams, even if you tend to glaze over on words like isopleth (a contour line of pressure).
In the Arctic, the summer sea ice has kept the Arctic Ocean cool. Recently Professor Peter Wadhams of Cambridge, expert on Arctic ice, has alerted the British newspaper, the Guardian, to a revised expectation that the summer Arctic sea ice is likely to be gone by 2016.
The summer sea ice area has shrunk from year to year, in what has been called a death spiral as vividly illustrated by Neven of the Arctic Sea Ice Blog. In September 2012 the sea ice has reached the lowest areal extent since records have been kept.
A correlation between declining Arctic sea ice and extreme weather has emerged. The altered Arctic weather loosens up the northern Jet Stream which instead of streaking around the high latitudes upper mid-latitudes, slows down and develops what look like the meanders of an old river. These loops in the Jet Stream act as blocking patterns that hold weather in place for longer periods of time, giving us heatwaves and super storms in the mid-latitudes, with the oddities of colder days further south and other new extremes. Dr Jennifer A. Francis of Rutgers has been showing the data on the relationship, of which a 16 minute video is a good introduction, hang in there with it and look at the diagrams, even if you tend to glaze over on words like isopleth (a contour line of pressure).
Where does the meltwater go in Greenland?
Greenland ice melt turns out to be more complicated, and better studied, so this is a revision of what I posted on September 18, 2012.
The top surface melt may either move slowly downwards, re-freezing and consolidating in firn, the form of old snow that is compressing into ice, or it may move as meltwater, or perhaps some other fate, for which I have yet to find a study. Sublimation?
The massive surface melt in the summer of 2012 was remarkable because nearly every surface experienced some melting, at least in place. The scientists monitoring Greenland melt had earlier classified Greenland ice as dry-snow facies, the combined percolation and wet-snow facies, ice facies, transient melt areas and moraine. Dry snow facies are surfaces where if snow falls, it accumulates, never melting. Percolation facies are surfaces that melt and refreeze, forming pipes and lenses. The
As a recent abstract by McGrath et al (2013) clarifies, "Extrapolation of this observed trend now suggests, with 95% confidence intervals, that the dry snow facies of the Greenland Ice Sheet will inevitably transition to percolation facies. There is a 50% probability of this transition occurring by 2025."
In the percolation facies is were the lakes and moulins form.
As the Greenland ice sheet melts around the edges and off its top surface, transient meltwater lakes form on the top of the ice at some locations. Sometimes the transient lakes discharge in transient mighty rivers that cut across the ice sheet surface and may join with more permanent rivers or perhaps better-termed seasonally recurrent rivers. In the summer of 2012 an engorged ice melt river destroyed a bridge in Kangerlussuaq. How many months of the year do the ice melt rivers flow? I don't know. How much melt water stays on the ice sheet surface all the way to ground surface and from there to the ocean, and how much melt water diverts through the moulins to under-ice channels before it reaches the ocean? I don't know those answers, either, and it would be great if someone was gathering real data on those questions.
In other instances, the meltwater lakes accumulate for only a few days or weeks in summer, then flush themselves down the inverse-chimneys, the moulins, that develop under the lakes and deep into the ice, as the melt water opens up cracks in the ice. In a moulin, the melt water creates a deep vertical shaft that extends to the base of the ice sheet. The moulin water is thought to travel through under-ice channels to the ocean. How well established is that fate? Does all the water go to the ocean?
Tracking ice melt comes with some tools, as ice melt is fresh water, low in salts and conductivity, and as it is from snow fall, it has a lighter oxygen isotope signature than does seawater.
Is it part of the freshwater runoff accumulation found in the seas near shore? Apparently yes.
The East Greenland Current and in consequence, the West Greenland Current, are affected by plumes of glacial melt water that can be detected far into the current by oxygen isotope studies.
Is the meltwater also pooling in the great central lowland of Greenland that is hidden under the ice? The data from the 1990s did not suggest that it was. The Greenland ice core samples from GISP, GSIP2, GRIP, NGRIP, and NEEM did not hit a lake of any sort before approaching bedrock.
However the times are a-changing. In the summer of 2012, the entire top ice surface of Greenland had a melt layer, unlike previous years' observations in which center of the continental sheet did not lose a layer. This years' loss of annual ice record is as startling as if a geologist could watch the loss of a geologic stratum.
Also in this past year, researchers at the other pole were able to drill down in Antarctica, to the ancient Lake Vostock, deep under the ice sheet. Is there another lake like Vostock forming under Greenland's melting ice sheet?
Like Antarctica, Greenland has a low bedrock area in mid-sub-continent as much as 500 meters below current sea level.
Researchers suggest that the Greenland meltwater from surface lakes may be lubricating the icesheet's bottom surface. With the slopes of that mid-continent depression, not all the ice sheet would slide towards the sea.
Two to five areas of Greenland bedrock have channel patterns linking the mid-continent depression to the sea.
These channels could unplug at some point in the mix of sea level rise and ice melt.
For now, the Greenland ice cores suggest, but don't prove, an absence of a preexisting mid-continental lake.
Perhaps it's one of those answers that is all of the above or some of the above.
In breaking news on November 30, 2012, a report published in Science, A reconciled estimate of Ice-Sheet mass balance, shows that Greenland's ice sheet is melting five times faster than the models had predicted.
Most recent update May 22, 2013. Joan Savage
The top surface melt may either move slowly downwards, re-freezing and consolidating in firn, the form of old snow that is compressing into ice, or it may move as meltwater, or perhaps some other fate, for which I have yet to find a study. Sublimation?
The massive surface melt in the summer of 2012 was remarkable because nearly every surface experienced some melting, at least in place. The scientists monitoring Greenland melt had earlier classified Greenland ice as dry-snow facies, the combined percolation and wet-snow facies, ice facies, transient melt areas and moraine. Dry snow facies are surfaces where if snow falls, it accumulates, never melting. Percolation facies are surfaces that melt and refreeze, forming pipes and lenses. The
As a recent abstract by McGrath et al (2013) clarifies, "Extrapolation of this observed trend now suggests, with 95% confidence intervals, that the dry snow facies of the Greenland Ice Sheet will inevitably transition to percolation facies. There is a 50% probability of this transition occurring by 2025."
In the percolation facies is were the lakes and moulins form.
As the Greenland ice sheet melts around the edges and off its top surface, transient meltwater lakes form on the top of the ice at some locations. Sometimes the transient lakes discharge in transient mighty rivers that cut across the ice sheet surface and may join with more permanent rivers or perhaps better-termed seasonally recurrent rivers. In the summer of 2012 an engorged ice melt river destroyed a bridge in Kangerlussuaq. How many months of the year do the ice melt rivers flow? I don't know. How much melt water stays on the ice sheet surface all the way to ground surface and from there to the ocean, and how much melt water diverts through the moulins to under-ice channels before it reaches the ocean? I don't know those answers, either, and it would be great if someone was gathering real data on those questions.
In other instances, the meltwater lakes accumulate for only a few days or weeks in summer, then flush themselves down the inverse-chimneys, the moulins, that develop under the lakes and deep into the ice, as the melt water opens up cracks in the ice. In a moulin, the melt water creates a deep vertical shaft that extends to the base of the ice sheet. The moulin water is thought to travel through under-ice channels to the ocean. How well established is that fate? Does all the water go to the ocean?
Tracking ice melt comes with some tools, as ice melt is fresh water, low in salts and conductivity, and as it is from snow fall, it has a lighter oxygen isotope signature than does seawater.
Is it part of the freshwater runoff accumulation found in the seas near shore? Apparently yes.
The East Greenland Current and in consequence, the West Greenland Current, are affected by plumes of glacial melt water that can be detected far into the current by oxygen isotope studies.
Is the meltwater also pooling in the great central lowland of Greenland that is hidden under the ice? The data from the 1990s did not suggest that it was. The Greenland ice core samples from GISP, GSIP2, GRIP, NGRIP, and NEEM did not hit a lake of any sort before approaching bedrock.
However the times are a-changing. In the summer of 2012, the entire top ice surface of Greenland had a melt layer, unlike previous years' observations in which center of the continental sheet did not lose a layer. This years' loss of annual ice record is as startling as if a geologist could watch the loss of a geologic stratum.
Also in this past year, researchers at the other pole were able to drill down in Antarctica, to the ancient Lake Vostock, deep under the ice sheet. Is there another lake like Vostock forming under Greenland's melting ice sheet?
Like Antarctica, Greenland has a low bedrock area in mid-sub-continent as much as 500 meters below current sea level.
Researchers suggest that the Greenland meltwater from surface lakes may be lubricating the icesheet's bottom surface. With the slopes of that mid-continent depression, not all the ice sheet would slide towards the sea.
Two to five areas of Greenland bedrock have channel patterns linking the mid-continent depression to the sea.
These channels could unplug at some point in the mix of sea level rise and ice melt.
For now, the Greenland ice cores suggest, but don't prove, an absence of a preexisting mid-continental lake.
Perhaps it's one of those answers that is all of the above or some of the above.
In breaking news on November 30, 2012, a report published in Science, A reconciled estimate of Ice-Sheet mass balance, shows that Greenland's ice sheet is melting five times faster than the models had predicted.
Most recent update May 22, 2013. Joan Savage
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