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Topics - prokaryotes

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A new study in Science shows that hundreds of massive, kilometre –wide, craters on the ocean floor in the Arctic were formed by substantial methane expulsions

The massive craters were formed around 12,000 years ago, but are still seeping methane and other gases. Illustration: Andreia Plaza Faverola

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Video transcript

Related press conference from 2016
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There are several hundred of craters in the area. Over one hundred of them are up to one kilometer wide. Illustration: K. Andreassen/CAGE

The craters are connected to deeper gas chimneys, showing gas flow from deeper hydrocarbon reservoirs. Hundreds of gas flares are seen in the water above. Illustration: M. Winsborrow

Related Links
Massive Craters Formed By Methane Blow-outs From The Arctic Sea Floor

Like ‘champagne bottles being opened’: Scientists document an ancient Arctic methane explosion

Methane GWP, How Bad of a Greenhouse Gas Is Methane?

Massive craters formed by methane blow-outs from the Arctic sea floor

Methane exploded from Arctic sea-floor as Ice Age ended

View of the methane seeps in the Arctic

Massive craters on Arctic Ocean floor caused by methane blow out

Scientists just found telltale evidence of an ancient methane explosion in the Arctic
/ A methane mound in the Canadian High Arctic, Stephen Grasby

Blow-out craters on the Arctic seafloor

Animation: From Glaciation to Global Warming – A Story of Sea Level Change (Titanic Belfast)

Methane clathrate

Images Methane bubbles collect under the ice (Natalia Shakhova)

Starting in the mid-1980s, the Defense Meteorological Satellite Program (DMSP) constructed eight “F-series” satellites, in bulk, with the plan to launch satellites in succession as each one failed to maintain a continuous record of Arctic sea ice extent.

But in 2016, Congress cut the program, resulting in the dismantling of the last, still not launched, satellite. It is now likely that an impending failure of the last DMSP satellites in orbit will leave the world blind until at least 2022, even as the Arctic shows signs of severe instability and decline.

While international and U.S. monitoring is still being done for ice thickness, the Trump administration has proposed cuts to satellite missions, including NOAA’s next two polar orbiting satellites, NASA’s PACE Satellite (to monitor ocean and atmospheric pollution), and the Orbiting Carbon Observatory 3 (for carbon dioxide atmospheric measurements).

All of these cuts in satellite monitoring come at a time when the world is seeing massive changes due to climate change, development and population growth. One satellite program spared Trump’s budgetary axe so far is Landsat 9, which tracks deforestation and glacial recession. How Congress will deal with Trump’s proposed cuts is unknown.

Science / The Sciences of Ice Shelf Meltwater (Retention vs Discharge)
« on: April 19, 2017, 07:41:08 PM »
Antarctic ice shelf potentially stabilized by export of meltwater in surface river

Here we present evidence for persistent active drainage networks—interconnected streams, ponds and rivers—on the Nansen Ice Shelf in Antarctica that export a large fraction of the ice shelf’s meltwater into the ocean. We find that active drainage has exported water off the ice surface through waterfalls and dolines for more than a century.

The surface river terminates in a 130-metre-wide waterfall that can export the entire annual surface melt over the course of seven days. During warmer melt seasons, these drainage networks adapt to changing environmental conditions by remaining active for longer and exporting more water. Similar networks are present on the ice shelf in front of Petermann Glacier, Greenland, but other systems, such as on the Larsen C and Amery Ice Shelves, retain surface water at present.

The underlying reasons for export versus retention remain unclear. Nonetheless our results suggest that, in a future warming climate, surface rivers could export melt off the large ice shelves surrounding Antarctica—contrary to present Antarctic ice-sheet models, which assume that meltwater is stored on the ice surface where it triggers ice-shelf disintegration.

Clip of Nansen Ice Shelf waterfall

I did not read the study paper, but it seems plausible that surface discharge is less of an issue when compared to moulin/fracturing discharge to bottom with potential for lubricating effects, and concerning stability.

Greenland and Arctic Circle / The Bølling-Allerød warming
« on: April 13, 2017, 11:05:26 PM »
I thought to open a discussion on the science related to the Bølling-Allerød warming, a period with exceptional rate of changes, as recorded in ice core records from Greenland/Northern Greenland. Then there is science related to the AMOC, and Volcanism.

Bølling–Allerød Interstade (BA), is a widespread abrupt warming event in the Northern Hemisphere during the deglacial transition, essentially synchronous in Alaska and Greenland (Praetorius and Mix, 2014).

The sea-surface warming of ∼3 ◦C in the Gulf of Alaska (GOA) record occurs abruptly (in <90 yrs), consistent with ice-core records that register this transition as occurring within decades (Steffensen et al., 2008).

The question is what causes the abrupt warming at the onset of the Bølling as seen in the Greenland ice cores. There is a clear antiphasing seen in the deglaciation interval between 20 and 10 ka. During the first half of this period, Antarctica steadily warmed, but little change occurred in Greenland. Then, at the time when Greenland’s climate underwent an abrupt warming, the warming in Antarctica stopped. A possible hypothesis can be that a sudden increase of the northward heat transport draws more heat from the south, and leads to a strong warming in the north. This “heat piracy” from the South Atlantic has been formulated by Crowley (1992). A logical consequence of this heat piracy is the Antarctic Cold Reversal (ACR) during the Northern Hemisphere warm Bølling/Allerød.

The bottom line seems to me, to identify involved mechanisms, but to be careful to draw conclusions as analog for today's climate, with different configurations, loading, and rates or warming. However, responsible mechanism are very likely to take part this time around as well, but might act differently, ie. AMOC, response times, regional differences.

Below a link to an excerpt by Jim White with a brief comment on the event, and a couple of related studies.

Abrupt Climate Change explained by Jim White, 12 Minutes excerpt (@AGU 2014)

July 16, 2009 BOULDER—By simulating 8,000 years of climate with unprecedented detail and accuracy, a team led by scientists from the University of Wisconsin–Madison and the National Center for Atmospheric Research (NCAR) has found a new explanation for the last major period of global warming, which occurred about 14,500 years ago.

In a period called the Bølling-Allerød warming, global sea level rose by 16 feet and temperatures in Greenland soared by up to 27 degrees Fahrenheit over several hundred years. The new study shows how increased carbon dioxide, strengthening ocean currents, and a release of ocean-stored heat could have combined to trigger the warming.

2016 On the Abruptness of Bølling–Allerød Warming
Using a high-resolution TCC-resolved regional model, it is found that this decadal-scale accumulation of OCAPE ultimately overshoots its intrinsic threshold and is released abruptly (~1 month) into kinetic energy of TCC, with further intensification from cabbeling. TCC has convective plumes with approximately 0.2–1-km horizontal scales and large vertical displacements (~1 km), which make TCC difficult to be resolved or parameterized by current general circulation models. The simulation herein indicates that these local TCC events are spread quickly throughout the OCAPE-contained basin by internal wave perturbations. Their convective plumes have large vertical velocities (~8–15 cm s−1) and bring the WSW to the surface, causing an approximate 2°C sea surface warming for the whole basin (~700 km) within a month. This exposes a huge heat reservoir to the atmosphere, which helps to explain the abrupt Bølling–Allerød warming.

Related talk from AGU 2014 Thermobaric instability / and modelling of warm salty water getting to the surface. The role of the ocean in the last deglaciation

2017 The Atlantic Meridional Overturning Circulation and Abrupt Climate Change
Abrupt changes in climate have occurred in many locations around the globe over the last glacial cycle, with pronounced temperature swings on timescales of decades or less in the North Atlantic. The global pattern of these changes suggests that they reflect variability in the Atlantic meridional overturning circulation (AMOC). This review examines the evidence from ocean sediments for ocean circulation change over these abrupt events. The evidence for changes in the strength and structure of the AMOC associated with the Younger Dryas and many of the Heinrich events is strong. Although it has been difficult to directly document changes in the AMOC over the relatively short Dansgaard-Oeschger events, there is recent evidence supporting AMOC changes over most of these oscillations as well. The lack of direct evidence for circulation changes over the shortest events leaves open the possibility of other driving mechanisms for millennial-scale climate variability.

2016 Abrupt Bølling warming and ice saddle collapse contributions to the Meltwater Pulse 1a rapid sea level rise
Elucidating the source(s) of Meltwater Pulse 1a, the largest rapid sea level rise caused by ice melt (14–18 m in less than 340 years, 14,600 years ago), is important for understanding mechanisms of rapid ice melt and the links with abrupt climate change. Here we quantify how much and by what mechanisms the North American ice sheet could have contributed to Meltwater Pulse 1a, by driving an ice sheet model with two transient climate simulations of the last 21,000 years. Ice sheet perturbed physics ensembles were run to account for model uncertainties, constraining ice extent and volume with reconstructions of 21,000 years ago to present. We determine that the North American ice sheet produced 3–4 m global mean sea level rise in 340 years due to the abrupt Bølling warming, but this response is amplified to 5–6 m when it triggers the ice sheet saddle collapse.

2014 An ice core record of near-synchronous global climate changes at the Bølling transition

2014 Abrupt pre-Bølling–Allerød warming and circulation changes in the deep ocean

Volcanism linked to BA

Related Modelling suggests with ice cap melt, an increase in volcanic activity

2016 Interaction between climate, volcanism, and isostatic rebound in Southeast Alaska during the last deglaciation
We evaluate the timing and climate context of a deglacial volcanic sequence from Southeast Alaska.
We document an increase in volcanism in response to deglacial ice loss and isostatic rebound.
These data support the hypothesis that regional deglaciation can rapidly trigger volcanic activity.
An increase in regional climate variability is associated with the interval of intense volcanism.
This study illustrates a two-way coupling of climate and volcanism across time scales.

The sudden increase in volcanic activity from the MEVF coincides with the onset of Bølling–Allerød interstadial warmth, the disappearance of ice-rafted detritus, and rapid vertical land motion associated with modeled regional isostatic rebound in response to glacier retreat. These data support the hypothesis that regional deglaciation can rapidly trigger volcanic activity. Rapid sea surface temperature fluctuations and an increase in local salinity (i.e., δ18Osw) variability are associated with the interval of intense volcanic activity, consistent with a two-way interaction between climate and volcanism in which rapid volcanic response to ice unloading may in turn enhance short-term melting of the glaciers, plausibly via albedo effects on glacier ablation zones.

Two plausible mechanisms could have linked the interval of isostatic adjustment with enhanced volcanism: 1) increased melt production generated through decompression in the shallow mantle (Maclennan et al., 2002), or 2) reduced storage time of crustal magmas through regional adjustment in crustal stress and enhanced dike formation (Rawson et al., 2016). The near-zero timelag between regional isostatic adjustment and an abrupt increase in volcanic eruptive frequency in Southeast Alaska suggests the latter scenario is more plausible, or at least the dominant mechanism.

Supporting this supposition is the rapid mobilization of differentiated magma through multiple vents. Decompression melting would not likely have produced differentiated magmas on the time-frames observed, while previous work by others has shown that the Mount Edgecumbe magma chamber likely contained cupolas above the main basaltic chamber that already contained the more siliceous material (e.g. Myers and Sinha, 1985; Riehle et al., 1992b).

The rapid response of the Southeast Alaska system contrasts with inferred lags of volcanism several thousand years behind sealevel rise in global compilations (Kutteroff et al., 2013; Watt et al., 2013). It is plausible to think that some volcanic systems may have longer lag times behind local unloading; for example, arc systems in thicker continental crust may have longer response times (Rawson et al., 2016) than relatively isolated volcanic systems with shallow magma chambers, such as in Southeast Alaska (Riehle et al., 1994). Nevertheless, our findings highlight the importance of well-constrained regional studies to understand the rates and sensitivity of interactions between surface processes and volcanic activity.

The δ18Osw reconstruction reveals low values, implying freshening of surface waters, between 14.6 and 14.0 ka. Although the rapid freshening of surface waters coincides with abrupt warming, the interval of freshening is not uniquely linked to the warmest temperatures, as there are intervals within the BA with equivalently high SSTs that do not show an apparent decrease in δ18Osw.

The interval with greatest apparent freshening and high variance in δ18Osw coincides with the interval of deposition of basaltic tephra, which is coeval with the rapid warming and disappearance of ice-rafted debris (IRD) at the onset of the Bølling Interstade (Fig. 5, Fig. S5). Although these initial tephra layers are thin (0.5 cm), the deposition of dark tephra in the ablation zone of glaciers could have reduced albedo of the snow and ice surfaces (Conway et al., 1996), thereby promoting rapid melting and accelerated local meltwater output along with deglaciation. This mechanism would likely have enhanced freshwater runoff into the Alaskan coastal currents during deglaciation, and this influx of low δ18O water would in turn have influenced the isotopic composition of near-surface waters.

Although firm attribution of specific causal relationships is difficult with only a few events, it is plausible that both hemispheric and regional forcings contribute to climate variability in the GOA region. While direct radiative-forcing effects from individual eruptions are unlikely to lead to long-term cooling due to the relatively short residence time of volcanic aerosols in the upper atmosphere (1–3 yrs), a prolonged increase in the frequency of eruptions could lead to either warming or cooling perturbations through ice-albedo, sea-ice, or CO2 feedbacks.

Modeling studies suggest that hemispheric cooling of decades to centuries can be initiated by the effects of multiple eruptions (McGregor et al., 2015; Pollack et al., 1993), or sea-ice feedbacks (Miller et al., 2012).

Sustained intervals of volcanism during the deglaciation may also have contributed to warming through increased CO2 emissions (Huybers and Langmuir, 2009), and ice-albedo feedbacks. Tephra deposited in the ablation zone of glaciers accelerates melting because the tephra (>5 μm) tends to remain at the ice surface as the glacier retreats (Conway et al., 1996).

Tephra that was once covered in the accumulation zone will at some point be uncovered in the ablation zone, where its growing concentration at the ice surface may provide a feedback for glacial melting in models (Peltier and Marshall, 1995).

In some instances thick ash (>10 mm) can act as a short-term insulating layer on glaciers (Dragosics et al., 2016), delaying melting in areas proximal to the vent, but the wider dispersal of finer ash particles will likely more than compensate this localize insulating effect through a greater surface area over which thin tephra layers will act to increase ablation rates.

Given the evidence for rapid retreat of marine terminating glaciers preceding/coinciding with the interval of frequent volcanic tephra deposition from the MEVF, it is plausible that tephra deposited on these regional glaciers would have an nearly immediate impact on melt rates in the already-expanding ablation zones. Thus, rapid responses of Alaskan volcanic systems to initial deglaciation may have accelerated ice losses in the region.

The large number of volcanoes in the Pacific “Ring of Fire”, coupled with the prevailing westerly winds, make deposition of tephra on the Laurentide and Cordilleran ice sheets (Fig. 1) a potential contributor to glacial wasting and ice-sheet instability

Greenhouse gases are considered one of the powerful feedback mechanisms in the ice age cycle. Might deglacial volcanism contribute to this effect? The rise of atmospheric CO2 during the first half of the deglaciation (18–15 ka) was likely sourced primarily from processes related to organic matter, as shown by δ13C (Schmitt et al., 2012; Bauska et al., 2016), plausibly through a decrease in the net strength of the ocean’s biological pump, which yields CO2 depleted in 13C relative to the atmosphere.

Later in the deglaciation (<15 ka), further trends of rising CO2 are not associated with long-term 13C depletion, and therefore could include contributions from either ocean warming or volcanic CO2, which both yield CO2 rise not depleted in 13C relative the background atmospheric values. Superimposed in these larger trends are abrupt (∼10 ppm) rises in atmospheric CO2 near 16–16.5 ka, 14.5–14.7 ka, and 11.5–12 ka (Marcott et al., 2014).

Carbon isotope data from ice core CO2 constrain the youngest and oldest of these abrupt rises to be sourced primarily from organic carbon reservoirs, most likely on land (Bauska et al., 2016), but could allow partial contributions from other sources including volcanic CO2.

The abrupt rise in atmospheric CO2 near 14.7–14.5 ka, however, has no discernable change in atmospheric δ13C (Bauska et al., 2016) implying that it cannot be sourced from oxidation of organic matter and therefore may be consistent with volcanic sources that responded relatively quickly to deglacial unloading.

This finding is consistent with the hypothesis that ice-unloading can trigger volcanism. We find no significant lag between the timing of major ice retreat and the onset of volcanism, suggesting that the volcanic response to deglaciation is rapid in this region. Between 14.6–13.1 ka, the MEVF exhibited an eruption recurrence interval of ∼1.5 events/century based on the macroscopic tephra-fall units identified in this study.

Early in the eruptive sequence, basaltic tephra is associated with surface water freshening (implied by anomalously low δ18Osw), suggesting that in this region, volcanism triggered by deglacial unloading may plausibly accelerate melting and water runoff through an albedo effect of dark tephra on snow and ice. With this insight from a well constrained regional study, re-examination of the integrated sulfate record from the Greenland ice core suggests that sustained early deglacial volcanism could accelerate rapid melting of some northern hemisphere glaciers through a reduction in surface albedo. Regional volcanism may thus play a significant role in century-to millennial scale climate change during the deglaciation.

2016 Abrupt Climate Change Experiments: The Role of Freshwater, Ice Sheets and Deglacial Warming for the Atlantic Meridional Overturning Circulation

Consequences / Algae and Hydrogen Sulfide outgassings
« on: October 02, 2016, 06:07:02 PM »
Sep 2016 Green algae: The body of the dead jogger found in Brittany exhumed
After the death of wild boar, a report from the Anses had highlighted the strong suspicion as to the hydrogen sulphide emissions (H2S) from the decomposing algae

Global warming led to climatic hydrogen sulfide and permian extinction
February 21, 2005

Related lecture by Peter Ward

Greenland and Arctic Circle / The Greenland Climate Project
« on: September 19, 2016, 03:06:47 PM »
The Greenland Climate Project works to probe water around Greenland, often under harsh conditions, their YouTube channel has some interesting footage, documenting the daily struggles and explaining the expedition, and the science involved.

Video overview

Their latest video


Glaciers / 2015 Tsunami at Tyndall Glacier (Alaska)
« on: September 18, 2016, 10:53:46 PM »
A landslide 2015 caused a giant mega tsunami. After a period of heavy rains, a mountainside near Tyndall Glacier (Alaska) collapsed into a fiord of Icy Bay on October 17, 2015. The displaced water generated a 100 meter high wave that sheared alders more than 500 feet up on a hillside across from the slide.



The giant wave of Icy Bay

The Tyndall Glacier landslide: images from the University of Alaska Fairbanks


1958 Lituya Bay megatsunami

A new Climate State video series uses 3D to visualize current climate related news. While there are videos with 3D data visualizations it would be nice to get these products for custom creations. Flyby, different angles, placing ships, creation of scenery.

Also looking for sea floor pingos, siberian permafrost crater formation sites, Greenland and Antarctica famous glaciers, permafrost models, clathrates and so on.

I work in Unreal Engine and it is possible to reproduce environments to some degree, but it is often a very time consuming process (preparing materials, textures etc). 

Example production


A new study indicates that under the frigid weight of Barents Sea Ice sheet, which covered northern Eurasia some 22 000 years ago, significant amounts of methane may have been stored as hydrates in the ground. As the ice sheet retreated, the methane rich hydrates melted, releasing the climate gas into the ocean and atmosphere for millennia.
This finding was published in January 2016 in Nature Communications, publication “Ice-sheet-driven methane storage and release in the Arctic”

If the same process of methane storage is occurring under the current ice sheets, there may be a new threat to take into the account when we are discussing ice sheet retreat in the future. (Source + video)

Also consider this suggestion by Bill McGuire
My concern, however, is that there may be a threat of submarine landslides around the margins of Greenland, which are less well explored. Greenland is already uplifting, reducing the pressure on the crust beneath and also on submarine methane hydrates in the sediment around its margins, and increased seismic activity may be apparent within decades as active faults beneath the ice sheet are unloaded. This could provide the potential for the earthquake or methane hydrate destabilisation of submarine sediment, leading to the formation of submarine slides and, perhaps, tsunamis in the North Atlantic. (Source)

Your thoughts?

Consequences / Rapid episodes of warming, explain
« on: December 26, 2015, 03:44:23 PM »

What are the chances or indications for rapid episodes of global warming? Past years showed continued rise with year after year breaking annual records. In above image (Link ) you can see that the trend spikes currently in 2015. In the monthly visual here you can see that the temps show something like a switch behavior (compare northern hemisphere regional monthly temps), though maybe this is the norm, idk. In this video Jim White elaborates on Greenland atmospheric circulations which he assumes changed drastically when temperatures jumped abruptly.

Are there any signs which can be considered to show potential for the beginning of rapid episodes, or are we still in a rather linear realm of change?

Is there anything very strange going on over at Greenland (or elsewhere). Are there any special blocking patterns forming, or remarkable temperature anomalies (outside of the observed norm), or fluctuations of temperature patterns maybe (as i mention above), special atmospheric changes - which could indicate something very spectacular has begun? Or are we just witnessing the continuation and reinforcement of patterns already identified (persistence / behavior)?

What could be the observational signs, before a rapid warmth episode takes place?

Patterns i would identify
- Extreme and unusual weather around the world
- Plateau of temperatures for a couple of years (per ice core data)
- Regional fluctuations of temperature (That's just my personal thought)

Consequences / Volcanism and seismicity with climate change
« on: May 17, 2015, 08:05:51 PM »
Since there is no discussion yet, i open it with this post from WAPO (2014).

Science explains why volcanoes are erupting all over the place right now

Additionally, McGuire a volcanologist, noted possible connections about earthquakes (video), and cautioned

Modelling suggests that as the ice cap continues to melt, so there will be a measurable increase in volcanic activity

Based on past changes, it appears that with the increase of sea level rise, that we can expect a response from the Earth's crust in the future.

Overview of the world with 6 meters of SLR

The forum / A forum for Ocean Environment?
« on: September 22, 2013, 12:01:33 AM »
Since ocean acidification, ocean saturation, ocean stratification, ocean anoxia/euxinia, ocean currents, ocean biogeochemical cycling etc are an emerging climate danger, i wonder if we could get such a forum here?

Otherwise where should i post such topics? Thanks.

Science / Anoxia and Euxinia Ocean Environmental Change
« on: September 21, 2013, 11:47:44 PM »
A compilation of the science and current research

These findings support an episode of ocean acidification coincident with the major biotic crisis. The Mo and U isotope records exhibit significant rapid negative anomalies at the onset of the main extinction interval, suggesting rapid expansion of anoxic and euxinic marine bottom waters during the extinction interval. The rapidity of the isotope excursions in Mo and U suggests substantially reduced residence times of these elements in seawater relative to the modern, consistent with expectations for a time of widespread anoxia.

West Antarctica Warmed Quickly ... 20,000 Years Ago
"West Antarctica is influenced by the ocean much more than the ice up high in East Antarctica, so you are able to see this [warming] happening before you notice it in East Antarctica," Fudge said. "We're seeing something similar in the modern climate, where West Antarctica seems to be changing more quickly."

The findings also resolve a long-standing problem: The timing of polar melting when the ice age ended. Based on earlier ice core records, mainly from East Antarctica, researchers had thought Antarctica warmed up 18,000 years ago, about 2,000 years after the Northern Hemisphere had warmed. Climate modelers sought to explain the delay through shutdowns in ocean currents (which help carry heat across the globe), among other factors.

Now, the warming in West Antarctica matches the onset of warming in the Northern Hemisphere, also pegged at 20,000 years ago.

Is the following statement correct?

Even more ominously, a wedge of cold water at the surface spreading out from the poles would push hotter, saltier water toward the ocean bottom. Fresh water is less dense than salty water, so the fresh water pulses from glaciers and melting ice bergs will act as a wedge, driving the denser, warmer, saltier water toward the bottom The net effect of such changes would be a shallower and weaker ocean circulation system as more warm water is averted toward the ocean bottom near the equator and then spreads northward and as warmer surface waters toward the poles and temperature regions are driven toward the sea-bed.

If above statement is correct, how far (if) does this influence bottom water formation in the Arctic Circle, especially in regions like the ESAS?

Is there a better explanation about the impact of increased freshwater runoff into the Arctic through the major rivers? (Links to science papers are welcome)


Deep Arctic Ocean warming during the last glacial cycle
In the Arctic Ocean, the cold and relatively fresh water beneath the sea ice is separated from the underlying warmer and saltier Atlantic Layer by a halocline. Ongoing sea ice loss and warming in the Arctic Ocean1, 2, 3, 4, 5, 6, 7 have demonstrated the instability of the halocline, with implications for further sea ice loss. The stability of the halocline through past climate variations8, 9, 10 is unclear. Here we estimate intermediate water temperatures over the past 50,000 years from the Mg/Ca and Sr/Ca values of ostracods from 31 Arctic sediment cores. From about 50 to 11 kyr ago, the central Arctic Basin from 1,000 to 2,500 m was occupied by a water mass we call Glacial Arctic Intermediate Water. This water mass was 1–2 °C warmer than modern Arctic Intermediate Water, with temperatures peaking during or just before millennial-scale Heinrich cold events and the Younger Dryas cold interval. We use numerical modelling to show that the intermediate depth warming could result from the expected decrease in the flux of fresh water to the Arctic Ocean during glacial conditions, which would cause the halocline to deepen and push the warm Atlantic Layer into intermediate depths. Although not modelled, the reduced formation of cold, deep waters due to the exposure of the Arctic continental shelf could also contribute to the intermediate depth warming.

An international team of scientists, including Martin Jakobsson from the Department of Geological Sciences and Johan Nilsson from the Meteorological Department at Stockholm University, has published a new study in Nature Geoscience entitled "Deep Arctic Ocean warming during the last glacial cycle”. The researchers have reconstructed the temperature history of the intermediate and deep Arctic Ocean during the past 50,000 years, using novel geochemical techniques on microfossils in sediment cores from across the central Arctic Ocean. Remarkably, the results show that in the last ice age, from about 50,000 to 11,000 years ago, the central Arctic Basin between 1,000 and 2,500 m water depth was occupied by water that was generally 1–2 °C warmer than in the modern Arctic. This extraordinary finding, indicating that the glacial Arctic Ocean operated in a different dynamical regime, challenges the view of a general glacial cooling of the ocean.

The Arctic region has received considerable attention due to its sensitivity to the changing climate. Of particular concern is the rapid decline of the summer sea ice extent, which this year even may approach another record low since satellite observations begun 1979. The sea ice in the Arctic forms at the top of the ‘halocline’, a 200–300 m thick layer of low salinity seawater capping the Arctic Ocean. The low salinity of the halocline layer is reflects the high freshwater to the Arctic Ocean. The halocline is also very cold, close to freezing point of seawater near -2°C, protecting the sea ice from the deeper laying warmer and more saline Atlantic Water Layer that flows into the Arctic Ocean from the North Atlantic.

The new study published as a Letter in Nature Geoscience shows that the warm intermediate Atlantic Layer was displaced far downward in the glacial Arctic Ocean, resulting in a substantial warming at depths between 1000 and 2500 m. Based on a conceptual oceanographic model, the researchers propose a mechanism for the subsurface warming of the glacial Arctic Ocean: A reduced influx of freshwater to the Arctic Ocean acted to deepen the halocline and push the warm Atlantic Layer downward. Based on their results, the researchers conclude that the Arctic Ocean has a previously unrecognized high sensitivity to changes of the freshwater input over multiple timescales, which is manifested in large temperature excursions of the intermediate water layers.

Science / A user removes relevant content from the Wikipedia
« on: August 13, 2013, 10:45:00 PM »
Here i will post reverts or modification to climate science in the Wikipedia which are not valid.

Wikipedia entry: Polar amplification
August 13, 2013: A user removes relevant content (reference to a peer-reviewed study) from the wiki. This user is very busy to remove a lot of updates to climate relevant wikipedia entries

This user also removes mentions of "Merchants of Doubt"

Effects of climate change on humans
User removes link to recent science study review by NewScientist, without further commenting.

Science / Access literature, help
« on: August 08, 2013, 04:46:44 PM »
There was a topic here somewhere - to help share some papers on demand. Could somebody point me to it?

I need access to the following paper


Arctic freshwater input into the North Pacific could serve as a catalyst for methane hydrate destabilization, an event suggested as a precursor to the onset of the PETM.

Looking for commentary.


Video link

Extensive Dark Snow, Very Large Melt Lakes Visible Over West Slope of Greenland as Late Season Melt Pulse Continues by robertscribbler on August 5, 2013

Sat Image source: NSIDC

Methane visualization 4th August 2013 MODIS Terra & Aqua (MODIS Combined Value-Added) Aerosol Optical Depth via

I've compiled an excerpt from a recent research letter about ice melt in Antarctica nd Greenland.



  • Satellite radar altimetry since 2002 shows accelerated thinning (Amundsen Sea, Pine Island and Thwaites glacial ice streams)
    Laser altimetry shows thinning on 20 of 54 Antarctic ice shelves
    Ice shelves buttress their tributary glaciers, melt-induced thinning of the ice shelves drives a corresponding thinning and acceleration of the upstream glaciers
    Heat for basal melting occurs from wind-forced incursions of deeper and warmer water and from local surface waters warmed by summer sun
    Extensive melt-induced subglacial channels under Pine Island Glacier
    Bottom melt influences the structural integrity of the entire glacier
    Inland course and extent of, for example, troughs under Pine Island Glacier, follow tectonic rifts
    The rift systems, some of them sloping inward (landward), represent preferred routes for warm water penetration
    Basal melting has eroded and expanded a cavity under the Pine Island Ice Shelf, allowing more warm seawater (as warm as 4C) to access the underside
    Meltwater input to the surrounding ocean appears to have increased by 50% over a decade
    A newly discovered large subglacial basin deep in the interior of the Weddell Sea, under the present day Filchner Ice Shelf and its tributary glaciers
    Plausible redirection of warm coastal ocean currents into the Filchner trough beneath the Filcher-Ronneshelves As a consequence, basal melting increases by a factor of 20
    In general, a consistent picture emerges around Antarctica of ice and ice shelves responding rapidly via the ocean to changes in Southern Hemisphere wind pattern
    Patterns that themselves vary on timescales of years to decades in concert with global features such as El Niño–Southern Oscillation (ENSO)


  • Marine-terminating glaciers drain nearly 90% of the Greenland ice mass
    Under-ice motions (basal sliding) play a very large role in dynamics of ice sheet’s
    Vertical uplift, in excess of post glacial rebound, due to rapid crustal response to recent ice mass losses
    Uplift ‘pulses’ correlated with short-lived events such as seasonal surface melt anomalies
    Greenland Ice Sheet interacting extensively and rapidly with surrounding ocean (see Fig) and overlying atmosphere

Arctic sea ice / NASA Modis Terra Sat captures huge crack this week
« on: May 15, 2013, 07:50:41 PM »
Could only find the news in german (has images)

Maybe someone can point me to the english source or even some analysis?

It is assumed that a storm who passed the area caused this crack.

Consequences / Geomorphological Response
« on: May 12, 2013, 05:50:00 AM »
So my guess is that the geomorphological response will become more pronounced over time. There are decade old studies which show an uptake in seismic activity during abrupt SLR.

A short intro into this topic

Because of these features i doubt migrating to the poles is a feasible option. During MP1 (Meltwater Pulse 1) there has been substantial SLR in a couple of years. Though somebody pointed out that was a different situation, however today we have unprecedented rates of emissions.

I hope that all these Arctic & Antarctic missions or some at least focus on the required degree for seismic observations.

The rest / ClimateState - video streaming platform
« on: May 12, 2013, 03:24:19 AM »

just want to suggest to visit for a collection of climate science related videos. Maybe this is of use when communicating science or just to get some education on the various evolving climate topics.

If you think there is something important missing, user can "submit a video" (link at page footer).



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