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wili

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Re: Conservative Scientists & its Consequences
« Reply #1700 on: May 08, 2017, 09:20:13 PM »
ASLR, I just wanted to say again how much I appreciate all your interesting links and text, and especially how you take the time to preface each with your own brief evaluation of its significance. Your efforts are valued.

....

Perhaps slightly off topic here, but Macron appears to be wooing US scientists, conservative or otherwise, to come to France now.

https://www.youtube.com/watch?v=-AHhc7DTIsg
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1701 on: May 08, 2017, 09:52:49 PM »
Perhaps slightly off topic here, but Macron appears to be wooing US scientists, conservative or otherwise, to come to France now.

With Trump threatening to fire so many climate/environmental scientists after September 2017, this is good timing for France & bad timing for the USA.
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1702 on: May 09, 2017, 07:26:51 PM »
The linked reference quantifies how much Earth System Models have underestimated CO₂ emissions from the degradation of high-latitude Alaskan permafrost.

Róisín Commane et. al. (2017), "Carbon dioxide sources from Alaska driven by increasing early winter respiration from Arctic tundra", PNAS, doi: 10.1073/pnas.1618567114

http://www.pnas.org/content/early/2017/05/02/1618567114

Significance: "Rising arctic temperatures could mobilize reservoirs of soil organic carbon trapped in permafrost. We present the first quantitative evidence for large, regional-scale early winter respiration flux, which more than offsets carbon uptake in summer in the Arctic. Data from the National Oceanic and Atmospheric Administration’s Barrow station indicate that October through December emissions of CO2 from surrounding tundra increased by 73% since 1975, supporting the view that rising temperatures have made Arctic ecosystems a net source of CO2. It has been known for over 50 y that tundra soils remain unfrozen and biologically active in early winter, yet many Earth System Models do not correctly represent this phenomenon or the associated CO2 emissions, and hence they underestimate current, and likely future, CO2 emissions under climate change."

Abstract: "High-latitude ecosystems have the capacity to release large amounts of carbon dioxide (CO2) to the atmosphere in response to increasing temperatures, representing a potentially significant positive feedback within the climate system. Here, we combine aircraft and tower observations of atmospheric CO2 with remote sensing data and meteorological products to derive temporally and spatially resolved year-round CO2 fluxes across Alaska during 2012–2014. We find that tundra ecosystems were a net source of CO2 to the atmosphere annually, with especially high rates of respiration during early winter (October through December). Long-term records at Barrow, AK, suggest that CO2 emission rates from North Slope tundra have increased during the October through December period by 73% ± 11% since 1975, and are correlated with rising summer temperatures. Together, these results imply increasing early winter respiration and net annual emission of CO2 in Alaska, in response to climate warming. Our results provide evidence that the decadal-scale increase in the amplitude of the CO2 seasonal cycle may be linked with increasing biogenic emissions in the Arctic, following the growing season. Early winter respiration was not well simulated by the Earth System Models used to forecast future carbon fluxes in recent climate assessments. Therefore, these assessments may underestimate the carbon release from Arctic soils in response to a warming climate."
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jai mitchell

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Re: Conservative Scientists & its Consequences
« Reply #1703 on: May 10, 2017, 07:38:43 PM »
https://www.theguardian.com/environment/planet-oz/2017/may/09/planet-could-breach-15c-warming-limit-within-10-years-but-be-aware-of-caveats

Planet could breach 1.5C warming limit within 10 years, but be aware of caveats

A new study shows how a switch in a major climate system could accelerate global temperatures to a 1.5C limit, but some scientists are challenging the assumptions

This article describes a paper published this week that finds the Inter-Decadal Pacific Oscillation (IPO) has shifted to positive in 2014 and that its continued above average warming will lead to globally averaged surface temperatures reaching 1.5C before 2029.

Paper here:
http://onlinelibrary.wiley.com/doi/10.1002/2017GL073480/full
Trajectories toward the 1.5°C Paris target: Modulation by the Interdecadal Pacific Oscillation
Henley & King (2017)
DOI: 10.1002/2017GL073480

Abstract

Global temperature is rapidly approaching the 1.5°C Paris target. In the absence of external cooling influences, such as volcanic eruptions, temperature projections are centered on a breaching of the 1.5°C target, relative to 1850–1900, before 2029. The phase of the Interdecadal Pacific Oscillation (IPO) will regulate the rate at which mean temperature approaches the 1.5°C level. A transition to the positive phase of the IPO would lead to a projected exceedance of the target centered around 2026. If the Pacific Ocean remains in its negative decadal phase, the target will be reached around 5 years later, in 2031. Given the temporary slowdown in global warming between 2000 and 2014, and recent initialized decadal predictions suggestive of a turnaround in the IPO, a sustained period of rapid temperature rise might be underway. In that case, the world will reach the 1.5°C level of warming several years sooner than if the negative IPO phase persists.



See also: Paper's Author writeup here:  https://theconversation.com/global-warming-could-accelerate-towards-1-5-if-the-pacific-gets-cranky-77175
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1704 on: May 11, 2017, 05:51:22 PM »
With a hat-tip to jai, I re-post his recent reply from the carbon cycle thread:


"New study of Amazon river CO2 emissions shows that biosphere does not take up as much CO2 as once thought.

https://phys.org/news/2017-05-amazon-river-carbon-dioxide-emissions.html

Study finds Amazon River carbon dioxide emissions nearly balance terrestrial uptake


The results increase the most recent global estimates of CO2 emissions from rivers and lakes by almost 50%, with potentially huge implications for global climate policy


Paper here:  Henrique O. Sawakuchi et al, Carbon Dioxide Emissions along the Lower Amazon River, Frontiers in Marine Science (2017)
http://dx.doi.org/10.3389/fmars.2017.00076"



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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1705 on: May 12, 2017, 04:59:32 PM »
We should not ignore the decrease in albedo as mountain snow cover decreases around the world with continued global warming:

Saavedra, F. A., Kampt, S. K., Fassnacht, S. R., and Sibold, J. S.: Changes in Andes Mountains snow cover from MODIS data 2000–2014, The Cryosphere Discuss., doi:10.5194/tc-2017-72, in review, 2017.

http://www.the-cryosphere-discuss.net/tc-2017-72/

Abstract. The Andes Mountains span a length of 7,000 km and are important for sustaining regional water supplies. Snow variability across this region has not been studied in detail due to sparse and unevenly distributed instrumental climate data. We calculated snow persistence (SP) as the fraction of time with snow cover for each year between 2000–2014 from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite sensors (500 m, 8-day maximum snow cover extent) limited between 8 °S and 36 °S due high frequency of cloud (>30 % of the time) south and north of this range. We ran Mann-Kendall and Theil-Sens analyses to identify significant areas of change in SP and snow line (the line at lower elevation which SP=20%). We evaluated whether these trends in the context of temperature and precipitation (University of Delaware dataset) and climate indices (ENSO, SAM, PDO). North of 29 °S has limited snow cover, and few trends in snow persistence were detected. A large area (70,515 km2) with persistent snow cover between 29–36 °S experienced a significant loss of snow cover (2–5 fewer days of snow year−1). Snow loss was more pronounced (62 %) on the east side of the Andes. We also found a significant increase in the elevation of 10–30 m year−1 south of 29–30 °S. Decreasing SP correlates with decreasing precipitation, increasing temperature, and climate indices and it varies with latitude and elevation. ENSO indices better predicted SP conditions north of 31 °S, and the SAM better predicted SP south of 31 °S.
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Archimid

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Re: Conservative Scientists & its Consequences
« Reply #1706 on: May 13, 2017, 02:28:54 PM »
More errors identified in contrarian climate scientists' temperature estimates

https://www.theguardian.com/environment/climate-consensus-97-per-cent/2017/may/11/more-errors-identified-in-contrarian-climate-scientists-temperature-estimates

Extract:
A new study suggests there are remaining biases in the oft-corrected University of Alabama at Huntsville atmospheric temperature estimates

I want to point out the graph in the article which show the corrections over time that this "scientific" group made on their data set.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

jai mitchell

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Re: Conservative Scientists & its Consequences
« Reply #1707 on: May 13, 2017, 05:33:57 PM »
 >:(
just for the record, I don't consider ^^^these^^^ people to be 'conservative scientists'  I see them as ideologically captured morons who are wittingly or unwittingly working as a fifth column in the war against humanity's survival.
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1708 on: May 13, 2017, 06:23:18 PM »
>:(
just for the record, I don't consider ^^^these^^^ people to be 'conservative scientists'  I see them as ideologically captured morons who are wittingly or unwittingly working as a fifth column in the war against humanity's survival.

jai,

I agree with your point.  Focusing on denalist arguments gives 'conservative scientists' cover to allow them continue their BAU research pathway, while the world accelerates towards a cliff.

Best,
ASLR
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Archimid

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Re: Conservative Scientists & its Consequences
« Reply #1709 on: May 13, 2017, 06:51:34 PM »

>:(
just for the record, I don't consider ^^^these^^^ people to be 'conservative scientists'  I see them as ideologically captured morons who are wittingly or unwittingly working as a fifth column in the war against humanity's survival.

I only call them scientist because they had some publications in the past. You are probably right that they lost the privilege of calling themselves scientists a long time ago.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1710 on: May 14, 2017, 01:47:23 AM »
The implications of the linked reference is that we can expect more quasi-resonant amplification (QRA) associated extreme weather events than was previously expected:

Mann, M. E. et. al. (2017), “Influence of Anthropogenic Climate Change on Planetary Wave Resonance and Extreme Weather Events”, Scientific Reports 7, Article number: 45242; doi:10.1038/srep45242

https://www.nature.com/articles/srep45242


Abstract: “Persistent episodes of extreme weather in the Northern Hemisphere summer have been shown to be associated with the presence of high-amplitude quasi-stationary atmospheric Rossby waves within a particular wavelength range (zonal wavenumber 6–8). The underlying mechanistic relationship involves the phenomenon of quasi-resonant amplification (QRA) of synoptic-scale waves with that wavenumber range becoming trapped within an effective mid-latitude atmospheric waveguide. Recent work suggests an increase in recent decades in the occurrence of QRA-favorable conditions and associated extreme weather, possibly linked to amplified Arctic warming and thus a climate change influence. Here, we isolate a specific fingerprint in the zonal mean surface temperature profile that is associated with QRA-favorable conditions. State-of-the-art (“CMIP5”) historical climate model simulations subject to anthropogenic forcing display an increase in the projection of this fingerprint that is mirrored in multiple observational surface temperature datasets. Both the models and observations suggest this signal has only recently emerged from the background noise of natural variability.”
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1711 on: May 14, 2017, 06:05:24 PM »
The linked article is entitled: "How the IPCC becomes a climate change denial tool", and it discusses how AR5 is out of date and underestimates such issues as abrupt sea level rise and the correlation of extreme weather events to global warming.  While it is helpful to point-out that denialists are taking advantage of AR5 inherently being behind the times; it fails to call attention to recent research related to how dynamical climate sensitivity can result in substantially higher effective climate sensitivity than AR5 acknowledges:

http://scienceblogs.com/gregladen/2017/04/10/how-the-ipcc-becomes-a-climate-change-denial-tool/

Extract: "Climate science is progressing very rapidly, especially in some areas. There are things we know now, or that we feel fairly comfortable asserting as pretty likely, that one year ago, and certainly four years ago, were fairly uncertain or in some cases inconceivable.

Citing the most recent IPCC report about a climate change relate issues tells me two things:

1) You don’t read the literature or talk to climate scientists; and
2) You are not especially interested in an honest conversation about this important scientific and policy issue."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1712 on: May 18, 2017, 07:51:42 PM »
While the linked reference may well err on the side of least drama (including down-playing the impacts of Hansen's ice-climate feedback mechanism) it is a good first effort to quantify the impacts of potential abrupt sea level rise associated with ice-cliff failure and hydrofracting mechanisms; that are much more severe than what is cited in AR5:

Kopp et. al. (2017) "Implications of ice-shelf hydrofracturing and ice-cliff collapse mechanisms for sea-level projections", arXiv:1704.05597v1

https://arxiv.org/pdf/1704.05597.pdf

Abstract: "Probabilistic sea-level projections have not yet integrated insights from physical ice-sheet models representing mechanisms, such as ice-shelf hydrofracturing and ice-cliff collapse, that can rapidly increase ice-sheet discharge. Here, we link a probabilistic framework for sealevel projections to a small ensemble of Antarctic ice-sheet (AIS) simulations incorporating these physical processes to explore their influence on projections of global-mean sea-level (GMSL) and relative sea-level (RSL) change. Under high greenhouse gas emissions (Representative Concentration Pathway [RCP] 8.5), these physical processes increase median projected 21st century GMSL rise from ~80 cm to ~150 cm. Revised median RSL projections would, without protective measures, by 2100 submerge land currently home to > 79 million people, an increase of ~25 million people. The use of a physical model, rather than simple parameterizations assuming constant acceleration, increases sensitivity to forcing: overlap between the central 90% of the frequency distributions for 2100 for RCP 8.5 (93–243 cm) and RCP 2.6 (26–98 cm) is minimal. By 2300, the gap between median GMSL estimates for RCP 8.5 and RCP 2.6 reaches > 10 m, with median RSL projections for RCP 8.5 jeopardizing land now occupied by ~900 million people (vs. ~80 million for RCP 2.6). There is little correlation between the contribution of AIS to GMSL by 2050 and that in 2100 and beyond, so current sea-level observations cannot exclude future extreme outcomes. These initial explorations indicate the value and challenges of developing truly probabilistic sea-level rise projections incorporating complex ice-sheet physics."
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TeaPotty

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Re: Conservative Scientists & its Consequences
« Reply #1713 on: May 29, 2017, 11:07:26 PM »
The linked article is entitled: "How the IPCC becomes a climate change denial tool", and it discusses how AR5 is out of date and underestimates such issues as abrupt sea level rise and the correlation of extreme weather events to global warming.  While it is helpful to point-out that denialists are taking advantage of AR5 inherently being behind the times; it fails to call attention to recent research related to how dynamical climate sensitivity can result in substantially higher effective climate sensitivity than AR5 acknowledges:

http://scienceblogs.com/gregladen/2017/04/10/how-the-ipcc-becomes-a-climate-change-denial-tool/

Extract: "Climate science is progressing very rapidly, especially in some areas. There are things we know now, or that we feel fairly comfortable asserting as pretty likely, that one year ago, and certainly four years ago, were fairly uncertain or in some cases inconceivable.

Citing the most recent IPCC report about a climate change relate issues tells me two things:

1) You don’t read the literature or talk to climate scientists; and
2) You are not especially interested in an honest conversation about this important scientific and policy issue."


Thank you for this AbruptSLR. I've said this for a long time, and was even criticized by a few on this forum for it. It has nothing to do with me, or intelligence. Its a simple observation of the facts and scientific research.

I take this observation and combine it with politics to reach the conclusion that we have very little to hope for. Our owners and the political elite have succeeded in dividing the populace into two equally nonsensical polar camps. This is why months ago I said good riddance to NASA's shit scientists, those who for years upheld the status quo that can only lead to collapse of civilization. Those who for years ridiculed "climate alarmists". Fuck them.

For a good few years now, our greatest enemy has not been the "climate deniers", but most of the "climate movement" sheep who buy into all the corporate-sponsored greenwashing and political propaganda. Posting irrefutable facts on most forums, like Obama being a huge driver of climate change, or how we have yet to begin any serious climate action at all, is still met with tribalistic hostility. Facts be damned. As far as our owners are concerned, this is working wonderfully as intended.

I cant help but find myself thinking every day "we deserve this". I dont wish anyone ill, and I dont think the average person deserves whats coming. But who would pity the adult who hurts himself by thinking he can ignore the laws of physics like gravity?

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1714 on: June 04, 2017, 03:28:21 PM »
The linked reference presents new findings that the retreat of the Barents Sea Ice Sheet at the end of the last ice age resulted in the explosive release of methane from Arctic seafloor hydrates as overpressure from the ice sheet disappeared.  The researchers findings serve as a good past analogy of what may likely happen in the near-term future if the WAIS were to collapse, and/or if marine terminating glaciers in Greenland were to retreat rapidly.  As methane has a GWP100 of about 35 such explosive releases of methane could have a significant impact on global warming this century, which has not been considered in either AR5 or CMIP5:

K. Andreassen, A. Hubbard, M. Winsborrow, H. Patton, S. Vadakkepuliyambatta, A. Plaza-Faverola, E. Gudlaugsson, P. Serov, A. Deryabin, R. Mattingsdal, J. Mienert & S. Bünz (02 Jun 2017), "Massive blow-out craters formed by hydrate-controlled methane expulsion from the Arctic seafloor",Science, Vol. 356, Issue 6341, pp. 948-953, DOI: 10.1126/science.aal4500

http://science.sciencemag.org/content/356/6341/948

Abstract: "Widespread methane release from thawing Arctic gas hydrates is a major concern, yet the processes, sources, and fluxes involved remain unconstrained. We present geophysical data documenting a cluster of kilometer-wide craters and mounds from the Barents Sea floor associated with large-scale methane expulsion. Combined with ice sheet/gas hydrate modeling, our results indicate that during glaciation, natural gas migrated from underlying hydrocarbon reservoirs and was sequestered extensively as subglacial gas hydrates. Upon ice sheet retreat, methane from this hydrate reservoir concentrated in massive mounds before being abruptly released to form craters. We propose that these processes were likely widespread across past glaciated petroleum provinces and that they also provide an analog for the potential future destabilization of subglacial gas hydrate reservoirs beneath contemporary ice sheets."

"Methane takes the quick way out
Accounting for all the sources and sinks of methane is important for determining its concentration in the atmosphere. Andreassen et al. found evidence of large craters embedded within methane-leaking subglacial sediments in the Barents Sea, Norway. They propose that the thinning of the ice sheet at the end of recent glacial cycles decreased the pressure on pockets of hydrates buried in the seafloor, resulting in explosive blow-outs. This created the giant craters and released large quantities of methane into the water above."

See also:

http://gizmodo.com/hundreds-of-giant-seafloor-craters-produced-by-explosiv-1795721166

Extract: "The explosive release of methane gas from subglacial sediments produced massive craters on the seafloor. During a recent expedition to the area, Andreassen’s team documented well over a hundred of these craters, which measured between 300 and 1,000 meters (980 to 3,280 feet) wide. Hundreds of smaller craters measuring less than 300 meters wide were also observed, and the researchers identified more than 600 methane flares in-and-around the craters that are still spewing the gas, though at rates far lower than what transpired during the explosive phase. Some of these craters were identified in the 1990s, but new scanning techniques allowed the researchers to survey the seafloor comprehensively.

Importantly, Andreassen said similar blowouts could happen in the near future on account of climate change. Areas in front of retreating ice sheets in Greenland and West Antarctica could host underlying hydrocarbon reservoirs. These blowouts don’t happen very often, but their environmental impacts could be greater than the impacts of slow and gradual methane seepage, explained Andreassen."

&
https://phys.org/news/2017-06-massive-craters-methane-blow-outs-arctic.html

Extract: ""Our study provides the scientific community with a good past analogue for what may happen to future methane releases in front of contemporary, retreating ice sheets" concludes Andreassen."
« Last Edit: June 05, 2017, 12:46:02 AM by AbruptSLR »
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TerryM

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Re: Conservative Scientists & its Consequences
« Reply #1715 on: June 04, 2017, 11:57:09 PM »
The linked reference presents new findings that the retreat of the Barents Sea Ice Sheet at the end of the last ice age resulted in the explosive release of methane from Arctic seafloor hydrates as overpressure from the ice sheet disappeared.  The researchers find that serves as a good past analogy of what may likely happen in the near-term future if the WAIS were to collapse, and/or if marine terminating glaciers in Greenland were to retreat rapidly.  As methane has a GWP100 of about 35 such explosive releases of methane could have a significant impact on global warming this century, which has not been considered in either AR5 or CMIP5:

If the shelf or glacier is floating there would be no pressure change, and if ASLR adds depth and pressure above the clathrates wouldn't this tend to stabilize them? Could they be referencing a time when the ice was solid all the way to the floor of Barents, or at least a time when the water was trapped entirely beneath the ice?


K. Andreassen, A. Hubbard, M. Winsborrow, H. Patton, S. Vadakkepuliyambatta, A. Plaza-Faverola, E. Gudlaugsson, P. Serov, A. Deryabin, R. Mattingsdal, J. Mienert & S. Bünz (02 Jun 2017), "Massive blow-out craters formed by hydrate-controlled methane expulsion from the Arctic seafloor",Science, Vol. 356, Issue 6341, pp. 948-953, DOI: 10.1126/science.aal4500

http://science.sciencemag.org/content/356/6341/948

Abstract: "Widespread methane release from thawing Arctic gas hydrates is a major concern, yet the processes, sources, and fluxes involved remain unconstrained. We present geophysical data documenting a cluster of kilometer-wide craters and mounds from the Barents Sea floor associated with large-scale methane expulsion. Combined with ice sheet/gas hydrate modeling, our results indicate that during glaciation, natural gas migrated from underlying hydrocarbon reservoirs and was sequestered extensively as subglacial gas hydrates. Upon ice sheet retreat, methane from this hydrate reservoir concentrated in massive mounds before being abruptly released to form craters. We propose that these processes were likely widespread across past glaciated petroleum provinces and that they also provide an analog for the potential future destabilization of subglacial gas hydrate reservoirs beneath contemporary ice sheets."

"Methane takes the quick way out
Accounting for all the sources and sinks of methane is important for determining its concentration in the atmosphere. Andreassen et al. found evidence of large craters embedded within methane-leaking subglacial sediments in the Barents Sea, Norway. They propose that the thinning of the ice sheet at the end of recent glacial cycles decreased the pressure on pockets of hydrates buried in the seafloor, resulting in explosive blow-outs. This created the giant craters and released large quantities of methane into the water above."

The above bolded emphasizes the subglacial component.

See also:

http://gizmodo.com/hundreds-of-giant-seafloor-craters-produced-by-explosiv-1795721166

Extract: "The explosive release of methane gas from subglacial sediments produced massive craters on the seafloor. During a recent expedition to the area, Andreassen’s team documented well over a hundred of these craters, which measured between 300 and 1,000 meters (980 to 3,280 feet) wide. Hundreds of smaller craters measuring less than 300 meters wide were also observed, and the researchers identified more than 600 methane flares in-and-around the craters that are still spewing the gas, though at rates far lower than what transpired during the explosive phase. Some of these craters were identified in the 1990s, but new scanning techniques allowed the researchers to survey the seafloor comprehensively.

Importantly, Andreassen said similar blowouts could happen in the near future on account of climate change. Areas in front of retreating ice sheets in Greenland and West Antarctica could host underlying hydrocarbon reservoirs. These blowouts don’t happen very often, but their environmental impacts could be greater than the impacts of slow and gradual methane seepage, explained Andreassen."

&
https://phys.org/news/2017-06-massive-craters-methane-blow-outs-arctic.html

Extract: ""Our study provides the scientific community with a good past analogue for what may happen to future methane releases in front of contemporary, retreating ice sheets" concludes Andreassen."

AFAIK There is but one tiny remnant of the once mighty Laurentide Glacier left, and very little sediment that we know of under the Greenland Ice Sheet. While the floor of Hudson Bay is pockmarked with the pingo like structures that CH4 leaves as a marking card, that heavily silted region has been deglaciated for millennia.
I do believe we're in trouble with Arctic clathrates, but believe that relatively hot water melting the frozen cap as well as dissociating the clathrates themselves will be the cause. The ESAS seems particularly unstable.
It's not impossible that vast silted or abiotic gas sources underlie Greenland's sheet, or WAIS, but the ice sheet left Barents and the rest of the Arctic Seas a long time ago.


Terry

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1716 on: June 05, 2017, 02:28:21 AM »
It's not impossible that vast silted or abiotic gas sources underlie Greenland's sheet, or WAIS, but the ice sheet left Barents and the rest of the Arctic Seas a long time ago.

The reference addresses a time when a marine ice sheet rested on the seafloor of what is now the Barents Sea, and the authors indicate that this paleo example could serve as an analogy to what may happen in the future if the marine ice sheet in West Antarctica where to collapse.  The attached image indicates how much methane may currently be trapped beneath both the WAIS and the EAIS, portions of which could be released this century per Pollard & DeConto's cliff failure and hydrofracturing based model projections.
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1717 on: June 08, 2017, 05:24:28 PM »
The linked Scribbler article highlights the fact that current climate model projections do not include potential future methane emissions associated with marine glacier/ice sheet retreat.  Society may soon regret such omissions.

"New Study: Ice Sheet Retreat Led to Rapid Methane Hydrate Release at End of Last Ice Age"

https://robertscribbler.com/2017/06/07/new-study-ice-sheet-retreat-led-to-rapid-methane-hydrate-release-at-end-of-last-ice-age/

Extract: "At the end of the last ice age, a warming world released a portion of its carbon stores into the atmosphere. The result was, ultimately, an increase in atmospheric CO2 by around 100 parts per million and in increase in atmospheric methane by around 300 parts per billion.
This increase in greenhouse gasses was a direct response to the Earth warming by approximately 4 degrees Celsius over the course of about 10,000 years. Under a present human-forced warming that is currently 1.2 C above late 19th Century averages and that is predicted to reach between 3.3 and 7 C warming this Century if fossil fuel burning continues, it is important to consider what additional carbon forcing the Earth System will produce under such an extreme and short-term temperature departure.

Researchers also indicated that places presently locked in surface ice — like Greenland and Antarctica — could generate further methane blow out risk as ice sheets melt, withdraw and remove pressure from the methane deposits beneath them.

These are important findings due to the fact that paleoclimate evidence of past large-scale hydrate release provides a study-identified mechanism for how permafrost hydrates and gas deposits are being liberated due to present warming, how such warming may increase their rate of liberation in the future, and how ice sheet withdrawal could contribute to this hydrate liberation trend. What remains highly uncertain is the ultimate volume of hydrate response to a given level of warming over a given period and how significantly such releases would contribute to the already very considerable heat forcing provided by human emissions. That said, the new study does add to serious concerns regarding the potential for future warming and greenhouse gas levels — which will tend to be higher than present model studies indicate due to generally not accounting for these kinds of Earth System carbon feedbacks."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1718 on: June 08, 2017, 08:33:24 PM »
The linked article April 2, 2017 article is entitled: "Once more with feeling: Climate models don’t exaggerate warming".  It indicates that climate models with higher longer term sensitivity will have higher values for effective ECS; thus it is important which models we choose to put our faith in regarding our children's well-being.

https://arstechnica.com/science/2017/04/once-more-with-feeling-climate-models-dont-exaggerate-warming/

Extract: "Over the first hundred years of a gradually-increasing-CO2 simulation, the apparent sensitivity gets closer and closer to the true long-term sensitivity. But even around the end of that century, the true sensitivity is still (on average) around 25 percent greater than what you would calculate from the short-term response—a difference that can’t be ignored.

It’s actually even a little more complicated than that, because the number is higher for models with a higher longer-term sensitivity, which take a little longer to reach equilibrium. (Conversely, it’s lower for models with lower sensitivity.) This tells you something important: you can’t really truly calculate the long-term sensitivity from the short-term response alone."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1719 on: June 12, 2017, 10:01:07 PM »
The linked article suggests a future feedback between biomass fires in the Southern Hemisphere and decreasing albedo in Antarctica, with continued global warming.  To the best of my knowledge such a feedback is currently not included in any AR5 projections:

M. M. Arienzo et. al. (11 June 2017), "Holocene black carbon in Antarctica paralleled Southern Hemisphere climate", Journal of Geophysical Research -  Atmospheres; DOI: 10.1002/2017JD026599

http://onlinelibrary.wiley.com/doi/10.1002/2017JD026599/abstract?utm_content=bufferad755&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Abstract: "Black carbon (BC) and other biomass-burning (BB) aerosols are critical components of climate forcing but quantification, predictive climate modeling, and policy decisions have been hampered by limited understanding of the climate drivers of BB and by the lack of long-term records. Prior modeling studies suggested that increased Northern Hemisphere anthropogenic BC emissions increased recent temperatures and regional precipitation, including a northward shift in the Inter-Tropical Convergence Zone (ITCZ). Two Antarctic ice cores were analyzed for BC and the longest record shows that the highest BC deposition during the Holocene occurred ~8-6k years before present in a period of relatively high austral burning season and low growing season insolation. Atmospheric transport modeling suggests South America (SA) as the dominant source of modern Antarctic BC and, consistent with the ice-core record, climate model experiments using mid-Holocene and preindustrial insolation simulate comparable increases in carbon loss due to fires in SA during the mid-Holocene. SA climate proxies document a northward shifted ITCZ and weakened SA Summer Monsoon (SASM) during this period, with associated impacts on hydroclimate and burning. A second Antarctic ice core spanning the last 2.5k years documents similar linkages between hydroclimate and BC, with the lowest deposition during the Little Ice Age characterized by a southerly shifted ITCZ and strengthened SASM. These new results indicate that insolation-driven changes in SA hydroclimate and BB, likely linked to the position of the ITCZ, modulated Antarctic BC deposition during most of the Holocene and suggests connections and feedbacks between future BC emissions and hydroclimate."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1720 on: June 13, 2017, 03:19:52 PM »
The linked article is entitled: "NASA-MIT Study Evaluates Efficiency of Oceans as Heat Sink, Atmospheric Gases Sponge", & it indicates with continued warming the oceans will progressively absorb both less GHGs and less heat, … though its ability to absorb heat is more greatly reduced."  As their models do not include freshwater hosing, as modeled by James Hansen in his ice-climate feedback mechanism; this leaves the risk that a collapse of the WAIS collapsing this century could abruptly slow ocean circulation; which would abruptly slow heat absorption.

https://www.giss.nasa.gov/research/news/20170612/

Extract: "Using two computer models that simulate the ocean, NASA and MIT scientists found that gases are more easily absorbed over time than heat energy. In addition, they found that in scenarios where the ocean current slows down due to the addition of heat, the ocean absorbs less of both atmospheric gases and heat, though its ability to absorb heat is more greatly reduced."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1721 on: June 13, 2017, 03:48:40 PM »
The linked reference indicates that current models to not adequately account for the impacts (i.e. they underestimate the impacts) of internal climate variability (ICV) on ice mass loss from ice sheets:

Chii-Yun Tsai, et. al. (12 June 2017), "Assessing the contribution of internal climate variability to anthropogenic changes in ice sheet volume", Geophysical Research Letters, DOI: 10.1002/2017GL073443

http://onlinelibrary.wiley.com/doi/10.1002/2017GL073443/abstract?utm_content=bufferc7113&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Abstract: "Understanding ice sheet response to different sources of uncertainty in projecting the climate is essential for assessing long-term risk of sea-level rise (SLR). The impact of uncertainty caused by internal climate variability (ICV) on future ice sheet changes has not been assessed explicitly. Here we estimate how ICV affects ice sheet projections using a three-dimensional ice sheet model driven by climate fields from two large-ensembles of climate model simulations differing in initial climate states. We find that ICV causes approximately 2mm uncertainty in the estimated SLR due to Greenland ice sheet mass loss during 1992–2011, which is nearly double the observational uncertainty. Additionally, SLR difference due to ICV is about 17% of the mean total change of SLR in 2100. This study highlights a critical need to assess uncertainties of projecting ice sheet loss due to ICV to obtain robust estimates of both historical and future SLR."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1722 on: June 13, 2017, 04:29:53 PM »
The linked reference indicates that multiple different factors need to be considered to accurately account for hiatus decades.  Unfortunately, denialist will likely use this as an excuse to take ineffective action on climate change; while in fact these findings justify taking accelerated action against climate change, when one considers the complex nature of climate attractors:

Lukas von Känel, et. al. (12 June 2017), "Hiatus-like decades in the absence of equatorial Pacific cooling and accelerated global ocean heat uptake", Geophysical Research Letters, DOI: 10.1002/2017GL073578

http://onlinelibrary.wiley.com/doi/10.1002/2017GL073578/abstract

Abstract: "A surface cooling pattern in the equatorial Pacific associated with a negative phase of the Interdecadal Pacific Oscillation is the leading hypothesis to explain the smaller rate of global warming during 1998-2014, with these cooler than normal conditions thought to have accelerated the oceanic heat uptake. Here, using a 30-member ensemble simulation of a global Earth system model, we show that in 10% of all simulated decades with a global cooling trend, the eastern equatorial Pacific actually warms. Our finding challenges the view of the equatorial Pacific being the sole pacemaker for generating internal stochastic variability-driven global warming hiatus decades and suggests that past and future surface temperature patterns during hiatus decades may be distinct. In addition, the global ocean heat uptake tends to slow down during hiatus decades implying a fundamentally different global climate feedback factor on decadal timescales than on centennial timescales and calling for caution inferring climate sensitivity from decadal-scale variability."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1723 on: June 15, 2017, 09:40:23 AM »
As opposed to earlier err on the side of least drama reports, the Arctic soils (peatlands) store enormous quantities of nitrous dioxide that will be released with continued warming, which will create a strong positive feedback  :(.

Carolina Voigt, et. al. (2017), "Increased nitrous oxide emissions from Arctic peatlands after permafrost thaw", PNAS, vol. 114 no. 24, 6238–6243, doi: 10.1073/pnas.1702902114

http://www.pnas.org/content/114/24/6238.short?utm_content=buffere2b7f&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Significance
The Arctic is warming rapidly, causing permafrost soils to thaw. Vast stocks of nitrogen (>67 billion tons) in the permafrost, accumulated thousands of years ago, could now become available for decomposition, leading to the release of nitrous oxide (N2O) to the atmosphere. N2O is a strong greenhouse gas, almost 300 times more powerful than CO2 for warming the climate. Although carbon dynamics in the Arctic are well studied, the fact that Arctic soils store enormous amounts of nitrogen has received little attention so far. We report that the Arctic may become a substantial source of N2O when the permafrost thaws, and that N2O emissions could occur from surfaces covering almost one-fourth of the entire Arctic.

Abstract
Permafrost in the Arctic is thawing, exposing large carbon and nitrogen stocks for decomposition. Gaseous carbon release from Arctic soils due to permafrost thawing is known to be substantial, but growing evidence suggests that Arctic soils may also be relevant sources of nitrous oxide (N2O). Here we show that N2O emissions from subarctic peatlands increase as the permafrost thaws. In our study, the highest postthaw emissions occurred from bare peat surfaces, a typical landform in permafrost peatlands, where permafrost thaw caused a fivefold increase in emissions (0.56 ± 0.11 vs. 2.81 ± 0.6 mg N2O m−2 d−1). These emission rates match those from tropical forest soils, the world’s largest natural terrestrial N2O source. The presence of vegetation, known to limit N2O emissions in tundra, did decrease (by ∼90%) but did not prevent thaw-induced N2O release, whereas waterlogged conditions suppressed the emissions. We show that regions with high probability for N2O emissions cover one-fourth of the Arctic. Our results imply that the Arctic N2O budget will depend strongly on moisture changes, and that a gradual deepening of the active layer will create a strong noncarbon climate change feedback.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1724 on: June 17, 2017, 02:22:35 PM »
The linked reference indicates that due both to climate change and other human activities, wildfires have increase by 400 percent from 1985 to 2014 on the Great Plains of North America.

Victoria M. Donovan, et. al. (16 June 2017), "Surging wildfire activity in a grassland biome", Geophysical Research Letters, DOI: 10.1002/2017GL072901

http://onlinelibrary.wiley.com/doi/10.1002/2017GL072901/abstract

Abstract: "Rapid changes in wildfire patterns are documented globally, increasing pressure to identify regions that may experience increases in wildfire in future decades. Temperate grassland and savanna biomes were some of the most frequently burned regions on Earth; however, large wildfires have been largely absent from the Great Plains of North America over the last century. In this paper, we conduct an in-depth analysis of changes in large wildfire (>400 ha) regime characteristics over a 30 year period across the Great Plains. For the entire biome, (i) the average number of large wildfires increased from 33.4 ± 5.6 per year from 1985 to 1994 to 116.8 ± 28.8 wildfires per year from 2005 to 2014, (ii) total area burned by large wildfires increased 400%, (iii) over half the ecoregions had greater than a 70% probability of a large wildfire occurring in the last decade, and (iv) seasonality of large wildfires remained relatively similar."

See also:
"UNL researchers find 400 percent spike in wildfire destruction in Great Plains"

http://www.omaha.com/news/nebraska/unl-researchers-find-percent-spike-in-wildfire-destruction-in-great/article_d7d8443c-21bc-5e77-83a2-a8053f3047bd.html

Extract: "The grasslands of the Great Plains have seen one of the sharpest increases in large and dangerous wildfires in the past three decades, with their numbers more than tripling between 1985 and 2014, according to new research.
The study, published in the journal Geophysical Research Letters, found that the average number of large Great Plains wildfires each year grew from 33 to 117 over that time period, even as the area of land burned in these wildfires increased by 400 percent."

&

Jennifer K. Balch et. al. (2017), "Human-started wildfires expand the fire niche across the United States", PNAS, vol. 114 no. 11, 2946–2951, doi: 10.1073/pnas.1617394114

http://www.pnas.org/content/114/11/2946.full

“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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rboyd

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Re: Conservative Scientists & its Consequences
« Reply #1725 on: June 18, 2017, 08:39:39 PM »
Kevin Anderson: A deep systemic bias to <assume risky assumptions that makes things easier and ignore the risks of things that will make things harder>

Sums it up pretty well: ignore the feedbacks while accepting the future massive implementation of highly speculative negative emissions technologies. Add to that the use of 50%/66% probabilities for the climate scenarios, instead of a normal 95% level for risk analyses, to boost the carbon budget. At 95% there is no carbon budget, even using the UN IPCC assessment. Anything to not affect the assumption of continued economic growth.

Great delivery, especially the "you are part of the problem" to his audience.

https://www.youtube.com/watch?v=z3z4Ksy0Qa4

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1726 on: June 24, 2017, 07:41:44 PM »
As for all practical purposes the influence of permafrost degradation feedback was essentially omitted from AR5, the linked reference can be viewed a one ESLD attempt to introduce the impact of such feedback; which indicates up to a 12% increase in global warming by 2100 above the AR5 projections.

Burke, E. J., Ekici, A., Huang, Y., Chadburn, S. E., Huntingford, C., Ciais, P., Friedlingstein, P., Peng, S., and Krinner, G.: Quantifying uncertainties of permafrost carbon–climate feedbacks, Biogeosciences, 14, 3051-3066, https://doi.org/10.5194/bg-14-3051-2017, 2017.

http://www.biogeosciences.net/14/3051/2017/?utm_content=buffer35efc&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Abstract. The land surface models JULES (Joint UK Land Environment Simulator, two versions) and ORCHIDEE-MICT (Organizing Carbon and Hydrology in Dynamic Ecosystems), each with a revised representation of permafrost carbon, were coupled to the Integrated Model Of Global Effects of climatic aNomalies (IMOGEN) intermediate-complexity climate and ocean carbon uptake model. IMOGEN calculates atmospheric carbon dioxide (CO2) and local monthly surface climate for a given emission scenario with the land–atmosphere CO2 flux exchange from either JULES or ORCHIDEE-MICT. These simulations include feedbacks associated with permafrost carbon changes in a warming world. Both IMOGEN–JULES and IMOGEN–ORCHIDEE-MICT were forced by historical and three alternative future-CO2-emission scenarios. Those simulations were performed for different climate sensitivities and regional climate change patterns based on 22 different Earth system models (ESMs) used for CMIP3 (phase 3 of the Coupled Model Intercomparison Project), allowing us to explore climate uncertainties in the context of permafrost carbon–climate feedbacks. Three future emission scenarios consistent with three representative concentration pathways were used: RCP2.6, RCP4.5 and RCP8.5. Paired simulations with and without frozen carbon processes were required to quantify the impact of the permafrost carbon feedback on climate change. The additional warming from the permafrost carbon feedback is between 0.2 and 12 % of the change in the global mean temperature (ΔT) by the year 2100 and 0.5 and 17 % of ΔT by 2300, with these ranges reflecting differences in land surface models, climate models and emissions pathway. As a percentage of ΔT, the permafrost carbon feedback has a greater impact on the low-emissions scenario (RCP2.6) than on the higher-emissions scenarios, suggesting that permafrost carbon should be taken into account when evaluating scenarios of heavy mitigation and stabilization. Structural differences between the land surface models (particularly the representation of the soil carbon decomposition) are found to be a larger source of uncertainties than differences in the climate response. Inertia in the permafrost carbon system means that the permafrost carbon response depends on the temporal trajectory of warming as well as the absolute amount of warming. We propose a new policy-relevant metric – the frozen carbon residence time (FCRt) in years – that can be derived from these complex land surface models and used to quantify the permafrost carbon response given any pathway of global temperature change.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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jai mitchell

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Re: Conservative Scientists & its Consequences
« Reply #1727 on: June 28, 2017, 01:57:47 PM »
Meta Analysis of CO2 enrichment studies on plant growth shows that that published studies on the impacts of CO2 increases on plant growth are overestimated by 20-40%.  This indicates that projections of future crop production in a warming world are overestimated and that the projected land-based carbon sinks are assuming too much natural removal of CO2 from the atmosphere.

Has the Impact of Rising CO2 on Plants been Exaggerated by Meta-Analysis of Free Air CO2 Enrichment Studies?

http://journal.frontiersin.org/article/10.3389/fpls.2016.01153/full

Meta-analysis is extensively used to synthesize the results of free air CO2 enrichment (FACE) studies to produce an average effect size, which is then used to model likely plant response to rising [CO2]. The efficacy of meta-analysis is reliant upon the use of data that characterizes the range of responses to a given factor. Previous meta-analyses of the effect of FACE on plants have not incorporated the potential impact of reporting bias in skewing data. By replicating the methodology of these meta-analytic studies, we demonstrate that meta-analysis of FACE has likely exaggerated the effect size of elevated [CO2] on plants by 20 to 40%; having significant implications for predictions of food security and vegetation response to climate change. Incorporation of the impact of reporting bias did not affect the significance or the direction of the [CO2] effect.
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1728 on: June 30, 2017, 05:17:25 PM »
The linked reference demonstrates that the lower tropospheric atmosphere has been warming 140% faster since 1998 than scientists previously thought who were relying on unadjusted satellite data:

Carl A. Mears and Frank J. Wentz (2017), "A satellite-derived lower tropospheric atmospheric temperature dataset using an optimized adjustment for diurnal effects", Journal of Climate, https://doi.org/10.1175/JCLI-D-16-0768.1

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0768.1

Abstract: "Temperature sounding microwave radiometers flown on polar-orbiting weather satellites provide a long-term, global-scale record of upper-atmosphere temperatures, beginning in late 1978 and continuing to the present. The focus of this paper is a lower-tropospheric temperature product constructed using measurements made by the Microwave Sounding Unit channel 2, and the Advanced Microwave Sounding Unit channel 5. The temperature weighting functions for these channels peak in the mid to upper troposphere. By using a weighted average of measurements made at different Earth incidence angles, the effective weighting function can be lowered so that it peaks in the lower troposphere. Previous versions of this dataset used general circulation model output to remove the effects of drifting local measurement time on the measured temperatures. In this paper, we present a method to optimize these adjustments using information from the satellite measurements themselves. The new method finds a global-mean land diurnal cycle that peaks later in the afternoon, leading to improved agreement between measurements made by co-orbiting satellites. The changes result in global-scale warming (global trend (70S-80N, 1979-2016) = 0.174 C/decade), ~30% larger than our previous version of the dataset (global trend, (70S-80N, 1979-2016) = 0.134C/decade). This change is primarily due to the changes in the adjustment for drifting local measurement time. The new dataset shows more warming than most similar datasets constructed from satellites or radiosonde data. However, comparisons with total column water vapor over the oceans suggest that the new dataset may not show enough warming in the tropics."

See also the associated linked article:

Title: "Major correction to satellite data shows 140% faster warming since 1998"

https://www.carbonbrief.org/major-correction-to-satellite-data-shows-140-faster-warming-since-1998

Extract: "A new paper published in the Journal of Climate reveals that the lower part of the Earth’s atmosphere has warmed much faster since 1979 than scientists relying on satellite data had previously thought."
« Last Edit: June 30, 2017, 05:22:46 PM by AbruptSLR »
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rboyd

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Re: Conservative Scientists & its Consequences
« Reply #1729 on: June 30, 2017, 10:16:24 PM »
"However, comparisons with total column water vapor over the oceans suggest that the new dataset may not show enough warming in the tropics." So the warming may still be underestimated even after these adjustments. Still very good, as the RSS series was a big help to the deniers by understating the level of warming.

If I understand correctly, only the NASA GISS temperature series makes a reasonable attempt at filling in the data gaps at the poles.

http://www.metoffice.gov.uk/research/monitoring/climate/surface-temperature

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1730 on: July 01, 2017, 04:04:42 PM »
The linked Scribbler article is entitled: "Scorching 129 Degree (F) Temps Hit Iran; Severe June European Heatwave Attributed to Climate Change; Satellite Data Confirms Rapid Global Warming", that further elaborate on the Mears et al (2017) work:

https://robertscribbler.com/2017/06/30/scorching-129-degree-f-temps-hit-iran-severe-june-european-heatwave-attributed-to-climate-change-satellite-data-confirms-rapid-global-warming/

Extract: "Dr Carl Mears, a co-author of the new findings, in a statement to Carbon Brief noted:


By correctly accounting for the changes in satellite measurement times, the new satellite data are in better agreement with the surface data."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1731 on: July 02, 2017, 06:22:53 PM »
Due to Arctic Amplification, the extent and frequency of Siberian wildfires are accelerating at unprecedented rates, which constitutes a positive feedback mechanism that is underestimated in CMIP5:

Title: "Siberian Wildfire Can Be Seen From Space as Earth's Boreal Forests Burn at Unprecedented Rates"

https://www.ecowatch.com/nasa-siberian-wildfire-2450916592.html

Extract: "The space agency notes that at least 27,000 hectares (100 square miles) burned in the Irkutsk Oblast region of southern Siberia and another 27,000 hectares burned in neighboring states and regions.

The massive blaze, which started in late June, is yet another example of how the effects of climate change has dramatically impacted the uppermost Northern Hemisphere.

As Climate Central's Brian Kahn explained, "the region where fires are burning has been a hot spot on the global temperature map.""
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1732 on: July 02, 2017, 06:51:23 PM »
The linked reference uses discriminant analysis and the Bayesian theorem to reduce the uncertainty that anthropogenic radiative forcing is driving climate change.  Hopefully, AR6 will use similar analyses to decrease their uncertainty ranges; which should clarify that we are headed towards the upper end of the confidence ranges cited in AR5:

Heiko Paeth, Felix Pollinger, and Christoph Ring (2017), "Detection and attribution of multi-variate climate change signals using discriminant analysis and Bayesian theorem", Journal of Climate, https://doi.org/10.1175/JCLI-D-16-0850.1

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0850.1?utm_content=bufferc3e80&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Abstract: "Detection and attribution methods in climatological research aim at assessing whether observed climate anomalies and trends are still consistent with the range of natural climate variations or rather an indication of anthropogenic climate change. In this study, we pursue a novel approach by using discriminant analysis to enhance the distinction between past and future climates from state-of-art climate model simulations. The method is based on multi-variate fingerprints that are defined in the space of several prominent climate indices representing the thermal, dynamical and hygric aspects of climate change. Attribution is carried out by means of a Bayesian classification approach.

The leading discriminant function accounts for more than 99 % of total discriminability, with temperature variables, extratropical precipitation and extratropical circulation modes mainly contributing to the discriminant power. The misclassification probability between probability density functions of past and future climates is substantially reduced by the discriminant analysis: from >50% to <15%. Since the mid-1980s, the observed anomalies of the considered climate indices are more or less consistently attributed to a climate under strong radiative forcing, projected for the first half of the 21st century. We also assess the sensitivity of our results to different emissions scenarios from the CMIP3 and CMIP5 multi-model ensembles, seasons, prior probabilities for the early 21st-century climate, estimates of the observational error, lowpass filters, variable compositions, group numbers and reference data."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

rboyd

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Re: Conservative Scientists & its Consequences
« Reply #1733 on: July 04, 2017, 07:10:54 AM »
Another estimate of climate damages that uses incredibly low loss levels for a given rise in global temperatures - especially as they rise above 2-3 degrees centigrade.

Estimating economic damage from climate change in the United States

"Abstract
Estimates of climate change damage are central to the design of climate policies. Here, we develop a flexible architecture for computing damages that integrates climate science, econometric analyses, and process models. We use this approach to construct spatially explicit, probabilistic, and empirically derived estimates of economic damage in the United States from climate change. The combined value of market and nonmarket damage across analyzed sectors—agriculture, crime, coastal storms, energy, human mortality, and labor—increases quadratically in global mean temperature, costing roughly 1.2% of gross domestic product per +1°C on average. Importantly, risk is distributed unequally across locations, generating a large transfer of value northward and westward that increases economic inequality. By the late 21st century, the poorest third of counties are projected to experience damages between 2 and 20% of county income (90% chance) under business-as-usual emissions (Representative Concentration Pathway 8.5)."



http://science.sciencemag.org/content/356/6345/1362.full

TerryM

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Re: Conservative Scientists & its Consequences
« Reply #1734 on: July 05, 2017, 08:27:48 PM »
By Jove, if we let things go until we're 10C over preindustrial temperatures our grandchildren's country might slide into a moderate depression, and all the hardships that would entail.
Think of the carnage that a 10C temperature rise would have on the more southerly golf courses, the noise and vibration that larger AC systems would introduce in even the finest of yachts, and the need to limit ourselves to air conditioned arena polo, true field polo would become but a distant memory.
We must have the groundskeepers look into this dire possibility post haste!


Terry


PS
Perhaps a summer residence in Iqaluit should be contemplated. The day would hardly ever end, much of the Hampton's staff could commute twice yearly, and I've been given to understand that the northern lights can be quite beautiful at this latitude. We might even contemplate having a number of (plastic) replica igloos on the grounds to lend color to the place.
It's certainly a sobering warning, but every cloud and all that stuff.

Andre

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Re: Conservative Scientists & its Consequences
« Reply #1735 on: July 06, 2017, 01:31:53 AM »
It is starting to look more and more like we arent so lucky and climate sensitivity might be much higher than anticipated so far:

https://www.theguardian.com/environment/2017/jul/05/hopes-of-mild-climate-change-dashed-by-new-research?CMP=Share_iOSApp_Other

Hopes of mild climate change dashed by new research

"Hopes that the world’s huge carbon emissions might not drive temperatures up to dangerous levels have been dashed by new research.

The work shows that temperature rises measured over recent decades do not fully reflect the global warming already in the pipeline and that the ultimate heating of the planet could be even worse than feared.

How much global temperatures rise for a certain level of carbon emissions is called climate sensitivity and is seen as the single most important measure of climate change. Computer models have long indicated a high level of sensitivity, up to 4.5C for a doubling of CO2 in the atmosphere.

However in recent years estimates of climate sensitivity based on historical temperature records from the past century or so have suggested the response might be no more than 3C. This would mean the planet could be kept safe with lower cuts in emissions, which are easier to achieve.

But the new work, using both models and paleoclimate data from warming periods in the Earth’s past, shows that the historical temperature measurements do not reveal the slow heating of the planet’s oceans that takes place for decades or centuries after CO2 has been added to the atmosphere.

“The hope was that climate sensitivity was lower and the Earth is not going to warm as much,” said Cristian Proistosescu, at Harvard University in the US, who led the new research. “There was this wave of optimism.”

The new research, published in the journal Science Advances, has ended that. “The worrisome part is that all the models show there is an amplification of the amount of warming in the future,” he said. The situation might be even worse, as Proistosescu’s work shows climate sensitivity could be as high as 6C."


The Guardian article is based on this paper:

http://advances.sciencemag.org/content/3/7/e1602821

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1736 on: July 06, 2017, 02:28:59 AM »
It is starting to look more and more like we arent so lucky and climate sensitivity might be much higher than anticipated so far:

Andre,

Thanks for these new findings.  It would be nice to believe that decision makers will take these lessons to heart; but I am not so sure that they well.

Best,
ASLR

Edit:  Here is another article on the Cristian Proistosescu and Peter J. Huybers (2017) paper:

Titled: “Scientists are starting to clear up one of the biggest controversies in climate science “

https://www.washingtonpost.com/news/energy-environment/wp/2017/07/05/scientists-are-starting-to-clear-up-one-of-the-biggest-controversies-in-climate-science/?utm_term=.012567d68486


Extract: “The new study helps reconcile the models with the historical record. It suggests global warming occurs in different phases or “modes” throughout the planet, some of which happen more quickly than others. Certain slow-developing climate processes could amplify warming to a greater extent in the future, putting the models in the right after all. But these processes take time, even up to several hundred years, to really take effect — and because not enough time has passed since the Industrial Revolution for their signal to really develop, the historical record is what’s actually misleading at the moment.

This conclusion is supported by a growing body of research, which suggests that warming estimates made from the historical record alone are “potentially biased low, for reasons we are now just beginning to understand,” said Timothy Andrews, a climate scientist with the Met Office, the United Kingdom’s national weather service, in an email to The Washington Post." 
« Last Edit: July 06, 2017, 03:51:57 AM by AbruptSLR »
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1737 on: July 12, 2017, 04:24:14 PM »
Per the linked reference, & associated article, methane radiative forcing is about 25% higher than previously estimated in AR5 for shortwave forcing:

M. Etminan et al. Radiative forcing of carbon dioxide, methane, and nitrous oxide: A significant revision of the methane radiative forcing, Geophysical Research Letters (2016). DOI: 10.1002/2016GL071930

http://onlinelibrary.wiley.com/doi/10.1002/2016GL071930/abstract;jsessionid=4BD7EE5DBE1525CC15B5806E5EBEC6F4.f03t01

Abstract: “New calculations of the radiative forcing (RF) are presented for the three main well-mixed greenhouse gases, methane, nitrous oxide, and carbon dioxide. Methane's RF is particularly impacted because of the inclusion of the shortwave forcing; the 1750–2011 RF is about 25% higher (increasing from 0.48 W m−2 to 0.61 W m−2) compared to the value in the Intergovernmental Panel on Climate Change (IPCC) 2013 assessment; the 100 year global warming potential is 14% higher than the IPCC value. We present new simplified expressions to calculate RF. Unlike previous expressions used by IPCC, the new ones include the overlap between CO2 and N2O; for N2O forcing, the CO2 overlap can be as important as the CH4 overlap. The 1750–2011 CO2 RF is within 1% of IPCC's value but is about 10% higher when CO2 amounts reach 2000 ppm, a value projected to be possible under the extended RCP8.5 scenario.”

“Plain Language Summary
“Radiative forcing” is an important method to assess the importance of different climate change mechanisms, and is used, for example, by the Intergovernmental Panel on Climate Change (IPCC). Increased concentrations of greenhouse gases, such as carbon dioxide, methane and nitrous oxide, are the major component of the human activity that led the IPCC, in its 2013 Assessment, to conclude that “it is extremely likely that human influence is the dominant cause of warming since the mid-20th century.” In this letter, we report new and detailed calculations that aimed to update the simpler methods of computing the radiative forcing that have been used in IPCC assessments, and elsewhere. The major result is that radiative forcing due to methane is around 20-25% higher than that found using the previous simpler methods. The main reason for this is the inclusion of the absorption of solar radiation by methane, a mechanism that had not been included in earlier calculations. We examine the mechanisms by which this solar absorption causes this radiative forcing.The work has significance for assessments of the climate impacts of methane emissions due to human activity, and for the way methane is included in international climate agreements.”

See also:

https://phys.org/news/2017-01-effect-methane-climate-greater-thought.html

Extract: “Research led by the University of Reading indicates that emissions of methane due to human activity have, to date, caused a warming effect which is about one-third of the warming effect due to carbon dioxide emissions – this methane contribution is 25% higher than previous estimates."
« Last Edit: July 12, 2017, 04:31:48 PM by AbruptSLR »
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jai mitchell

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Re: Conservative Scientists & its Consequences
« Reply #1738 on: July 12, 2017, 07:06:16 PM »
1.  kind of counter intuitive, absorption of shortwave forcing would (seem to) reduce incoming shortwave radiation?
2.  since the presence of CH4 in the atmosphere is short-lived, a 14% increase in the 100-year timeline would indicate a MUCH greater increase in the 20-year forcing timeline (135% of CO2 on 20-year scale?) 
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Re: Conservative Scientists & its Consequences
« Reply #1739 on: July 14, 2017, 05:52:12 PM »
The linked reference cites findings from an improved version of CESM that increases ESM from 4.1C to 5.6C.  If this is actually experienced this coming century, this is bad news for both people & the current biota:

William R. Frey & Jennifer E. Kay (2017), "The influence of extratropical cloud phase and amount feedbacks on climate sensitivity", Climate Dynamics; pp 1–20, doi:10.1007/s00382-017-3796-5

https://link.springer.com/article/10.1007%2Fs00382-017-3796-5?utm_content=bufferfdbc0&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Abstract: "Global coupled climate models have large long-standing cloud and radiation biases, calling into question their ability to simulate climate and climate change. This study assesses the impact of reducing shortwave radiation biases on climate sensitivity within the Community Earth System Model (CESM). The model is modified by increasing supercooled cloud liquid to better match absorbed shortwave radiation observations over the Southern Ocean while tuning to reduce a compensating tropical shortwave bias. With a thermodynamic mixed-layer ocean, equilibrium warming in response to doubled CO2 increases from 4.1 K in the control to 5.6 K in the modified model. This 1.5 K increase in equilibrium climate sensitivity is caused by changes in two extratropical shortwave cloud feedbacks. First, reduced conversion of cloud ice to liquid at high southern latitudes decreases the magnitude of a negative cloud phase feedback. Second, warming is amplified in the mid-latitudes by a larger positive shortwave cloud feedback. The positive cloud feedback, usually associated with the subtropics, arises when sea surface warming increases the moisture gradient between the boundary layer and free troposphere. The increased moisture gradient enhances the effectiveness of mixing to dry the boundary layer, which decreases cloud amount and optical depth. When a full-depth ocean with dynamics and thermodynamics is included, ocean heat uptake preferentially cools the mid-latitude Southern Ocean, partially inhibiting the positive cloud feedback and slowing warming. Overall, the results highlight strong connections between Southern Ocean mixed-phase cloud partitioning, cloud feedbacks, and ocean heat uptake in a climate forced by greenhouse gas changes."
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jai mitchell

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Re: Conservative Scientists & its Consequences
« Reply #1740 on: July 14, 2017, 06:00:17 PM »
Interesting, the mid-latitude impact is in the Southern Hemisphere.  I expect that this will be at least partially offset by the near-equable climate regime produced in the Northern Hemisphere under a June 21 Arctic Sea ice fee condition.

However, the associated LW feedback under this scenario, with much greater water vapor content allowed in the Norther Hemisphere is also a significant positive feedback, one that I have yet to see in the Peer Review.
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1741 on: July 14, 2017, 06:17:40 PM »
Interesting, the mid-latitude impact is in the Southern Hemisphere.  I expect that this will be at least partially offset by the near-equable climate regime produced in the Northern Hemisphere under a June 21 Arctic Sea ice fee condition.

However, the associated LW feedback under this scenario, with much greater water vapor content allowed in the Norther Hemisphere is also a significant positive feedback, one that I have yet to see in the Peer Review.

It is also interesting that the work does not include freshwater hosing from a probable WAIS collapse ala Hansen's ice-climate feedback mechanism.  The fact that much of the mid-latitude impact is on the Southern Ocean only increases the probability of a WAIS collapse sooner rather than later.
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jai mitchell

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Re: Conservative Scientists & its Consequences
« Reply #1742 on: July 14, 2017, 07:23:59 PM »
I expect that the timeline for this is still (within the models and modeler's minds) extremely uncertain and is therefore not a priority (as the permafrost associated emissions were treated in the AR4 and AR5)
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1743 on: July 14, 2017, 08:00:48 PM »
I expect that the timeline for this is still (within the models and modeler's minds) extremely uncertain and is therefore not a priority (as the permafrost associated emissions were treated in the AR4 and AR5)

ACME is closely associated with CESM and Phase 1 of the ACME program is scheduled to be completed at the end of 2017, so it will be interesting to see if the ACME findings back-up the CESM findings.
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1744 on: July 15, 2017, 04:23:07 PM »
I do not find it reassuring that the behavior of the Southern Ocean plays large roles in both Frey & Kay (2017)'s estimate of an ECS of 5.6C and in Hansen et al (2016)'s ice-climate feedback mechanism, and yet scientists do not adequately understand the decadal variability of this unique region as discussed in the reference below:

Latif, M., Martin, T., Reintges, A. et al. (2017) "Southern Ocean Decadal Variability and Predictability", Curr Clim Change Rep, doi:10.1007/s40641-017-0068-8

https://link.springer.com/article/10.1007%2Fs40641-017-0068-8?utm_content=bufferc013d&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer

Abstract: "The Southern Ocean featured some remarkable changes during the recent decades. For example, large parts of the Southern Ocean, despite rapidly rising atmospheric greenhouse gas concentrations, depicted a surface cooling since the 1970s, whereas most of the planet has warmed considerably. In contrast, climate models generally simulate Southern Ocean surface warming when driven with observed historical radiative forcing. The mechanisms behind the surface cooling and other prominent changes in the Southern Ocean sector climate during the recent decades, such as expanding sea ice extent, abyssal warming, and CO2 uptake, are still under debate. Observational coverage is sparse, and records are short but rapidly growing, making the Southern Ocean climate system one of the least explored. It is thus difficult to separate current trends from underlying decadal to centennial scale variability. Here, we present the state of the discussion about some of the most perplexing decadal climate trends in the Southern Ocean during the recent decades along with possible mechanisms and contrast these with an internal mode of Southern Ocean variability present in state-of-the art climate models."

For Frey & Kay (2017) see:

William R. Frey & Jennifer E. Kay (2017), "The influence of extratropical cloud phase and amount feedbacks on climate sensitivity", Climate Dynamics; pp 1–20, doi:10.1007/s00382-017-3796-5

I also do not find it reassuring that if the WAIS collapses this century the effective ECS could be pushed into the 7.5 to 8.5C range (for several decades around the end of this century) which could then push the NH atmosphere into an equable climate pattern.
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1745 on: July 15, 2017, 08:44:52 PM »
Low cloud cover (LCC) is associated with negative climate change feedback; thus the finding of the linked reference that LCC decreases with continued warming indicates that ECS is likely higher than assumed by AR5:

Daniel T. McCoy, Ryan Eastman, Dennis L. Hartmann, and Robert Wood (2017), “The Change in Low Cloud Cover in a Warmed Climate Inferred from AIRS, MODIS, and ERA-Interim”, Journal of Climate, https://doi.org/10.1175/JCLI-D-15-0734.1

http://journals.ametsoc.org/doi/10.1175/JCLI-D-15-0734.1

Abstract: “Decreases in subtropical low cloud cover (LCC) occur in climate model simulations of global warming. In this study 8-day-averaged observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Atmospheric Infrared Sounder (AIRS) spanning 2002–14 are combined with European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis to compute the dependence of the observed variability of LCC on various predictor variables. Large-scale thermodynamic and dynamic predictors of LCC are selected based on insight from large-eddy simulations (LESs) and observational analysis. It is found that increased estimated inversion strength (EIS) is associated with increased LCC. Drying of the free troposphere is associated with decreased LCC. Decreased LCC accompanies subsidence in regions of relatively low EIS; the opposite is found in regions of high EIS. Finally, it is found that increasing sea surface temperature (SST) leads to a decrease in LCC. These results are in keeping with previous studies of monthly and annual data. Based upon the observed response of LCC to natural variability of the control parameters, the change in LCC is estimated for an idealized warming scenario where SST increases by 1 K and EIS increases by 0.2 K. For this change in EIS and SST the LCC is inferred to decrease by 0.5%–2.7% when the regression models are trained on data observed between 40°S and 40°N and by 1.1%–1.4% when trained on data from trade cumulus–dominated regions. When the data used to train the regression model are restricted to stratocumulus-dominated regions the change in LCC is highly uncertain and varies between −1.6% and +1.4%, depending on the stratocumulus-dominated region used to train the regression model.”
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Re: Conservative Scientists & its Consequences
« Reply #1746 on: July 17, 2017, 12:14:28 PM »
"Abrupt emergence of a large pockmark field in the German Bight, southeastern North Sea"


https://www.nature.com/articles/s41598-017-05536-1

Due to the shallow water depths and energetic conditions at the presumed time of eruption, a large fraction of the released gas must have been emitted to the atmosphere. Conservative estimates amount to 5 kt of methane, equivalent to 67% of the annual release from the entire North Sea.
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TerryM

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Re: Conservative Scientists & its Consequences
« Reply #1747 on: July 17, 2017, 08:16:21 PM »
"Abrupt emergence of a large pockmark field in the German Bight, southeastern North Sea"


https://www.nature.com/articles/s41598-017-05536-1

Due to the shallow water depths and energetic conditions at the presumed time of eruption, a large fraction of the released gas must have been emitted to the atmosphere. Conservative estimates amount to 5 kt of methane, equivalent to 67% of the annual release from the entire North Sea.
Thanks for the link.
If we ever again have ice thick enough to carry my weight I intend to find out if my local gas eruption is still actively leaking.


https://www.youtube.com/watch?v=UdYum6v48S8


The above 28 second video is indicative of the volume and force of the June 2015 eruption.
I arrived ~2 weeks later and made what observations I could, with the intention of returning in winter to see if methane bubbles were being trapped in the ice. Unfortunately the last two winters have been too warm to conduct my little experiment.


The area near the watercourse that exploded has a minimum of 7 meters of hard packed clay with no visible sand. There are holes smaller than a golf ball, but large enough to insert a thumb into that must extend through the clay matrix & down to wherever the gas had/has accumulated.


There are no gas lines nor municipal dump sites anywhere near the golf course, although N. America's first commercial oil patch is some tens of miles south & a large salt mine is located some tens of miles north.


If we ever again get some solid ice I still plan to attack it with ice pick and lighter to find out if a seep is still active.


Terry
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1748 on: July 17, 2017, 11:30:33 PM »
Current (CMIP5) climate models assume that land sinks will absorb more carbon dioxide than the linked reference indicates that they actually will:

Mark A. Bradford (2017), "Soil carbon: A leaky sink", Nature Climate Change, Volume: 7, Pages: 475–476, doi:10.1038/nclimate3332

http://www.nature.com/nclimate/journal/v7/n7/full/nclimate3332.html

Extract: "Ambitious greenhouse–gas emissions cuts are needed to limit the global mean annual temperature increase to 1.5 °C above preindustrial levels. A study now finds that the land sink for CO2 appears much smaller than is currently factored into climate models, suggesting that emissions cuts may need to be even more ambitious than currently estimated."
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #1749 on: July 18, 2017, 06:05:18 PM »
However, the associated LW feedback under this scenario, with much greater water vapor content allowed in the Norther Hemisphere is also a significant positive feedback, one that I have yet to see in the Peer Review.

For what it is worth, I note that the William R. Frey & Jennifer E. Kay (2017), that ECS may be between 4.1 and 5.6C, can be seen as an improvement on the Tan et al (2016) work that indicated that ECS may well be between 5.0 and 5.3C.

Ivy Tan, Trude Storelvmo & Mark D. Zelinka (08 Apr 2016), "Observational constraints on mixed-phase clouds imply higher climate sensitivity", Science, Vol. 352, Issue 6282, pp. 224-227, DOI: 10.1126/science.aad5300

If sufficient Peer Reviewed articles document this behavior it will be harder for AR6 to treat such findings as outliers.
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