The "Abrupt Methane Eruption" Conspiracy of the Arctic!

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2040 Ice-free Arctic? Wadhams says is bizarre

Dear Dr. Serreze: Is is true that 2017 had the lowest average ice volume in the Arctic? And is it true that the Arctic has lost over 75% of its ice volume? How do you think the Arctic won't be ice free until 2040? I live in Minnesota so I know a lake can have great "ice extent" as area whereas the volume gets very thin and then in a couple days the lake is ice free. Thanks, Drew Hempel

US Navy predicts summer ice free Arctic by 2016 | Nafeez Ahmed ...

https://www.theguardian.com › Environment › Climate change

Dec 9, 2013 - US Navy predicts summer ice free Arctic by 2016. Is conventional modelling out of pace with speed and abruptness of global warming? Arctic Sunrise among broken floes of Arctic sea ice. Greenpeace icebreaking ship, Arctic Sunrise, among broken floes of Arctic sea ice, photographed from the air.

http://www.telegraph.co.uk/science/2016/10/07/experts-said-arctic-sea-ice-would-melt-entirely-by-september-201/

This “claim” was obviously nonsense and was

very irresponsible.  Yes, the arctic sea ice is

losing volume (in all seasons) but I have

no idea where the cited number of 75% comes 

from.  When will the Arctic lose its summer 

sea ice cover?  Somewhere in the 2040s is a 

Reasonable estimate, but natural climate 

Variability is strong in the Arctic so it may 

well be later or earlier. And of course there are unknowns

regarding future rates of carbon emissions.

It is also important to remember that there will

Be winter ice for centuries.  It’s just that the

Winter ice will be thin and won’t survive the

Summer melt period. If you want to keep track of

What the sea ice is doing, google “arctic sea ice 

news and analysis”;  we have regularly updated

Maps and graphs  regular discussion of what is 

happening. 

Mark C Serreze

Sent from my iPhone

Thank you Dr. Serreze!

Is this quote about 75% volume decline wrong? Thanks again! drew
“. . we can also say with great confidence that the decline in observed ice thickness is not just an effect of measurement sampling and that the total sea ice volume has been declining over the past 32 years at astonishing rates (for instance a 75% reduction in September volume from 1979 to 2011).”
From: 'Arctic Sea Ice Volume: PIOMAS, Prediction, and the Perils of Extrapolation', Guest Commentary by Axel Schweiger, Ron Lindsay, and Cecilia Bitzin in RealClimate.org, April 11, 2012.

OK,,  good to see you are looking at PIOMAS.  I don't know what they said in 2012. However, September of 2012 was a record low for extent and volume.  From what I can see in their latest discussion, the PIOMAS folk are saying that October 2017 volume was 65% below the maximum October ice volume in 1979, so we are certainly talking big numbers.  Remember that PIOMAS is a data assimilation model - it provides estimates, not truth.
Serreze

Thank you again Dr. Serreze!

I appreciate your dialog Dr. Serreze because when I asked NASA Dr. Gavin Schmidt why they used 1950 as their "pre-industrial" baseline for global average temperature increase I got no response. Maybe you know the answer? At any rate do you think http://arctic-news.blogspot.com is not an accurate source of analysis? Also isn't it true that you are relying on satellite data that had error due to salt in the snow?

 Vishnu Nandan, who is the lead author of the study we were mentioning in the beginning, declared for the University of Calgary

Sadly, Nandan thinks that the seasonal sea ice might disappear completely in the summer at some point between the years 2030 and 2040,

Arctic Ice Melting Faster than We Thought - Green and Growing

https://www.greenandgrowing.org/arctic-ice-melting/

Oct 25, 2017 - Recent news show the Arctic ice melting at a pace faster than scientists previously thought. An error in the satellite measurements showed they were wrong. ... The cause for this measurement error of the satellites is the salt found in the snow cover. This can speed up the melting process and we could end ...

http://nsidc.org/arcticseaicenews/2017/11/

Happy New Year,

drew

Drew

Sorry for the delay.  I'm not all that familiar with the arctic-news site.  I know a few of the names listed
as contributors but that is about it.   It's probably OK overall, but I would treat it with the appropriate grain of salt. 
That they highlight  "abrupt methane eruptions" - a very low probability event as far as I am aware,  is cause for pause. 
Sensationalism is not helpful.   If you want to know about what is going on about sea ice,  our site
is very solid - a new post came out yesterday (https://nsidc.org/arcticseaicenews/)

As to why Schmidt uses 1950 as the pre-industrial baseline, are you sure about this?  Looking the the GISS website (https://data.giss.nasa.gov/gistemp/) NASA uses a 1951-1980 baseline to compute anomalies,  which is still standard in many circles,  but we use 1981-2010 for sea ice, and NOAA now uses this as well I think.

Passive microwave retrievals  retrievals have a number of sources of error, and salt in the snow is one of them.  Ho important?  I don't know so I am copying our pssive microwave expert,  Walt Meier.

Cheers
Mark  C.  Serreze 

Hello Drew,

Mark passed your email along to me because of your question about salt in the snow on sea ice. You are referring to the recent Nandan et al. (2017) paper that indicates that sea ice thickness estimates from the ESA CryoSat-2 (CS2) sensor may have errors due to salinity in the overlying snow cover. This is a nice paper that brings up an important issue. CS2 is a radar altimeter that is measuring elevation by sending a pulse of energy from the sensor and measuring the time it takes to reflect off the surface back to the sensor. Since it is radar, the pulse is assumed to generally penetrate through the snow to the sea ice surface below. So it is assumed that is measuring the elevation of the sea ice above the water (called freeboard). However, there is a lot of uncertainty here. First, the snow weighs down the sea ice ice and needs to be corrected for with the snow depth/density, but we don’t really have good data for those values. There is also uncertainty in the ice density depending on how much salt is trapped with in the ice. Nandan et al. (2017) illuminate another source of uncertainty - the fact that salt can get wicked up into the snow layer above the ice. Radar is quite sensitive to salinity, so salt in the snow will affect where the radar pulse reflects. 

These errors will affect any volume estimates that use CS2 data. However, the salinity does not significantly affect the surface area/extent estimates from passive microwave sensors that we at NSIDC primarily use. Salinity does affect the microwave signal and first-year ice (ice formed since the previous summer melt) is much more saline than multiyear ice (ice that has survived at least one melt season) because melt water flushes out a lot of the salt trapped in the ice. This allows us to distinguish first-year ice from multi-year ice, but it doesn’t much affect the discrimination of ice from water, so it doesn’t lead to greater uncertainty in area and extent estimates.

Also, PIOMAS uses only the passive microwave extent/area data in the model, not CS2 data, so the Nandan et al. (2017) effect is not relevant for PIOMAS. In regards to the PIOMAS thickness/volume estimates, yes, 2012 showed a volume decrease of roughly 75%, but it has recovered a bit. There is a lot of variability, so it’s important to look at the long-term trend to understand the changes. It is still a significant decrease, but there is still a lot of fairly thick ice remaining north of Greenland and the Canadian Archipelago, partly because the winds blow toward that area and pile up ice. The summers are very short in that region, so there isn’t much time to melt ice, though some of that ice drifts out of the Arctic. In reality, there is likely to be at least some ice in that region that remains through the summer for the foreseeable future, but it will be a small amount, which is why the general threshold for an “ice-free Arctic Ocean” is 1 million sq km.

As Mark notes, the general consensus among scientists is ~2040, but we see a lot of variability in the data and models indicate that this results in at least an uncertainty range of at least +/-10 years depending on the natural variability in the system - i.e., the random chance of when relatively warm and relatively cold years occur. A couple really warm years in a row may put us at ice-free condition by 2030 or perhaps even earlier, whereas if we get some cooler years, it could delay ice-free conditions to 2050 or beyond. As Mark noted, predictions of ice-free by 2016 were preposterous and not seriously considered in the scientific community - there was just to much ice to melt out by 2016.

Natural variability is also an important factor in interpreting the Svalbard sea surface temperature data (SST) on the Arctic News website. The 1981-2011 value is averaging out a lot of variability - that’s why it is a nice smooth, slowly declining curve. That region is particularly variable in October because the ice cover is so variable due to the proximity of the location to the warm North Atlantic waters (essentially remnants of the Gulf Stream) that flow into the region. If the currents flow close to Svalbard it will keep the region ice-free longer; if the currents turn away from Svalbard, ice will form sooner. 

If the ice is present, the SST is essentially 0 C, but without ice the SST could be much warmer. As an example, say that location has ice two out of three years on average, but in a warmer year when the ice hasn’t yet formed, the SST is on average ~13 C. That gives you and average of about 4 C, which is what you see in the 1981-2011 average. But it means that this year is something that may occur normally once out of every 3 years. So Oct 2017 was not necessarily an extreme year. No doubt there is a generally warming trend, but I’d be very cautious about reading much into the Svalbard SST Oct 2017 data. Again, the key thing is to look at long-term trends (which is shown in the 0-100 m anomaly plot - about a 0.3 C increase since 1980).

Hope this info helps. Let me know if you have further questions.

walt

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Walt Meier, Senior Research Scientist

DAAC Scientist
National Snow and Ice Data CenterCIRES/University of Colorado, UCB 449
Boulder, CO 80309
Tel: +1-303-735-6276
Email: walt@nsidc.org

"If we knew what we were doing, it would not be
called research, would it?" - Albert Einstein
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Thank you Dr. Meier and Dr. Serreze: Regarding "abrupt methane eruptions" - Dr. Natalia Shakhova, et. al., indicate this could happen within 5 years, as per her recent interview with Nick Breeze. http://envisionation.co.uk/index.php/nick-breeze/203-subsea-permafrost-on-east-siberian-arctic-shelf-now-in-accelerated-decline Stating that each year now is possible:

This is what we call the turning point. To me, I cannot take the responsibility in saying there is a right point between the linear and exponential yet, but following the logic of our investigation and all the evidence that we accumulated so far, it makes me think that we are very near this point. And in this particular point, each year matters.

 As gas within the sedimentary basins of the ESAS have been accumulating for a million years with no way to be released earlier, the supply for currently occurring emissions is tremendous. Because the shelf area is very shallow (mean depth is less than 50 metres), a fraction of these emissions will reach the atmosphere. The problem is that this fraction would be enough to alter the climate on our planet drastically.

Do you have any comments regarding Dr. Shakhova's concerns? Do you think this is being "sensationalist" as her conclusions are based on empirical data that she collected.

Thank you again for your very detailed response that was very informative.

Hello Drew,

I’m not an expert in permafrost or subsea methane releases. I think it is a concern and increases in methane emissions is not surprising. But I think most experts in this area see a steady increase - not a sudden release. So it would contribute to warming but not in a catastrophic way. But I think as the article points out, there are still a lot of uncertainties in this area, so it’s hard to give clear predictions at this point.