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Messages - jai mitchell

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I am writing you from 2038 my connection may not last so I will make it quick.

Our first effective ice free year was 2021.  This was due primarily to a large global shift in atmospheric circulation where winter tem0eratures were often over 0c throughout the arctic.  As albedo and carbon cycle feedbacks kicked in our entire planet realized the near term impacts and the need for radical emission reductions.  By 2027 we had successfully cut global emissions by over 50%. 

During this time, however, our climate response whipsawed under sudden changes in atmospheric forcing primarily caused by aerosol reductions and a return to the solar cycle peak.  Catastrophic flood events swept the middle latitudes and the 10-year drought in the sahel drove millions to death or a migratory existence.  We had our first terminal heat stress i dex in central America in 2031.  We are currently developing a stratospheric geoengineeri ng protocol under UN guidance.

But we have already lost most of our major cities and a national relocation project is underway.

In 2029 the summer sea ice passed a critical threshold reaching ice free states in mid august.  The albedo feedback at this time suddenly shifted temperaturea above 75N latitudes a full8 C above the august and sept 2000 m3ans. 

This drove tropical heat and water vapor into the north atlantic and in the late summer of that year Hurricane Petra swept up the south-east slope of the Greenland ice sheet.  Precious years of accellerated surface melt had already honeycombed the southern dome and the massive amounts of warm rain produces a lateral hydraulic rift that accelerated up slope and down to thebase openo g a jager 1 km deep rift. 

This catastrophic release with associated cliff effect collapses produced mid-sheet lateral drain bores that sufficiently lubricated the surface sheet and produced a 300m slip joint that allowedfurther colla0se effects.  This melt impact was as strong or stronger than any cound in the late pliestocene and the surface atlantic cooling abruptly halted the AMOC.  Suddenly north atlantic sea surfa e temperatures produ ed  irculation shifts similar to the late dryas coolong pulse.  We have had massive sea level rise and extreme storm tracks in the southern states but our current climate cycle may Llow us to reduce global co2 levels i. The next 10 years to restore an annual ice sheet again

This is a very difficult question to answer and the best any of us can do is hazard a guess.
I'm voting 2020-2030.
I fully agree with your analysis/educated guess, dnem.

I wish you'd play devil's advocate and guess a reasoning for 2040-2050 or 2050-2060. Oh well...  ;)


There is massive amounts of uncertainty about where we are headed.  Within that uncertainty is the near term climate response which if you look at the available data you would have to be somewhat of a lukewarmer to expect our FIRST sea ice extent below 1M km^2 in the 2040-2050 time frame or later.

however, there are many ideas about what will happen once this occurs that could lead to slowing of the long-term sea ice impact (i.e. see Chris' "Slow transition" thread).  Some of these include increased cloudiness in summer melt season (This view has a very strong representation among the mainstream cryosphere climate modelers and scientists), leading to a rapid reduction in ice mass loss during the melt season or the freshwater lensing effect from Hansen's (et al.) exponential greenland ice melt (see ASLR's work on the "Hansen et al paper: 3+ meters SLR by 2100" also in Consequences.

If you assert that your understanding is the absolute truth then you have to have a reasoned analysis that clearly shows why these uncertainties are not going to produce the effect that others may expect.  There are also many, many other uncertainties that could also produce a slowing or even a return of sea ice even after the first few years of <1M km^2). 

we are talking about decadal timescales in dynamic system that even the most powerful super-computer models do not yet model accurately. 

In retrospect, you are right.  I was being far too conservative for conservatism's sake.   Interesting, you caught me self-censoring my answer.  changed from 2040-2050 to 2030-2040.

Hi Jai,
Sorry, my eye just caught that edit of yours. Please don't censor yourself!
But here is a question for you, since you are (at least, compared to me) an old time poster here on ASIF.
Is there some form of peer-pressure or group-pressure here at ASIF for people to emit conservative guesses when it comes to the demise of Arctic sea ice? And for people to shut up when they question this conservative "bias"?
If so, I would think this is very strange. In any case, I am rather reassured that your poll is showing what it is showing: that approximately half the ASIF users are not conceding to the "conservative" peer pressure.

no, it is very clear that this is an open forum for discussion of these issues.  There are times when some concepts are clearly not supported by the scientific reality.  The conservative bias has been thoroughly addressed in other threads (i.e. conservative scientists and its consequences in the science section)

in the end we are all looking at this from our own perspective and in the spirit of open communication challenge each other's views whether they are conservative or not.

Arctic sea ice / Re: Stupid Questions :o
« on: April 21, 2017, 08:53:16 PM »
besides 200 years of study of the greenhouse effect properties of CO2, including the tuning of air to air missiles to the CO2 emission spectrum, the global warming impact of CO2 has been directly measured in 2 locations by LBNL.

please see my edit above:

It is impossible to determine these things without a strong explanation of the scale of early ag emission cycles.

Permafrost / Re: This is not good (methane clathrates)
« on: April 21, 2017, 05:18:41 PM »

Scientists just discovered telltale evidence of an ancient methane explosion in the Arctic ocean

Grasby, along with a team of scientists from institutes in Canada and Europe, discovered evidence for the ancient methane leak during a recent expedition to remote Ellef Ringnes Island in the Canadian Arctic, which they have described in a paper published this month in the Geological Society of America Bulletin. There, they found a cluster of 139 strange, rocky mounds, which they say were formed by a rapid release of large amounts of methane from the ocean floor.

paper here:

It would be very difficult to expect an aerosol forcing component in the historical trend based on agricultural cycles.


there is more than a number of papers that have determined that the late period cycle could (Edit:) NOT be driven by natural variability without a strong aerosol cloud effect in the tropics.

for example:

we conclude that models need external forcing to explain the magnitude, timing, and apparent multidecadal frequency of the observed twentieth century AMO variability.

u know bbr that was my first thought too but realized it would be impossible to show that the economic cycle drove the emission trend or if the temperature trend drove the economic cycle.  (I suspect the former)  It is interesting though that the KWave has shifted to a longer period than in the 1800s ( it used to be a 50 year cycle.

so basically, your contention of there not being a significant aerosol component to the 1930's trend is justified by the following long-series?

jai - another factor you've completely ignored is the completely different spatial/geographical distributions; high emissions in the early and mid-20th century would have been from Eurpope and North America. In recent decades those areas have seen reduced emissions while Asia/China have greatly accelerated.  Expecting the same forcing patter from completely different geographical distributions would seem a bit over-reaching - to put it charitably.

why don't you quote me where I did this.

wrt Mann's 70 year AMO cycle analysis is this the paper you refer to?  perhaps you want to back up your assertions with credible links to peer reviewed papers as I have?

for example, in the first graph, the 1920 line is actually 1917 (if you apply a grid function to determine the actual date instead of eyeballing it like I did)  and the 1935 graph line could reasonably be shifted to 1942 since this was when the emissions actually started to increase again (driving the shift in the AMO graph).

Besides how is it we don't see a change when MT Agung or MT Pinatubo erupted? 

Rainfall and cloud patterns are a Tropospheric loading effect with larger impacts from upper troposphere loading.  Stratospheric impacts act more like GHG.  What can you tell me about secondary cloud effects of tropospheric aerosols?

Actual AMO series below:

(note: never mind, I see that you do not have a science education background)

Please tell us the regression statistics. 

I already told you you have to adjust for relative forcing with impact of SO2 on tropical circulation (not simply a function of global forcing as regional impacts and high-altitude impacts appear to have much more weight).  This would be consistent with a simple model that shows relative impact of short-term aerosol emissions on the global system through the industrial period.  In addition, to accurately assess these impacts one would have to identify an overshoot effect from these short term changes based on the previous forcing history.  for example, shifts to positive AMO look to occur when SO2 emissions slow, revealing a strong signal that is being suppressed by aerosol emissions, however the break back to a negative AMO appears to happen quite suddenly when emissions begin to rise significantly - indicating a very large SO2 emission 'control knob' on the AMO function - as a function of relative forcing and energy imbalance and within a regional impact scale.

The lines are not arbitrary they are break points in both graphs and within the period of smoothing for the AMO using multiple models and Within the scale of emissions, they actually line up much better than I would expect.

for example, in the first graph, the 1920 line is actually 1917 (if you apply a grid function to determine the actual date instead of eyeballing it like I did)  and the 1935 graph line could reasonably be shifted to 1942 since this was when the emissions actually started to increase again (driving the shift in the AMO graph).

my apologies
I thought you came from an MBA background and worked in manufacturing

Merging the emissions graph and Mann et al's "true AMO" graph yields:

Why do you suppose that the intensity of the 1930 change in aerosols would have the same effect in 1978?  The effect is driven by RELATIVE forcing compared to the GHG forcing component, not absolute.  In addition, the use of this graph must be framed within a dynamic fluid system that has inertia of forcing impacts  So the scale of the emissions is not as important as the breakpoints as shown below.

In addition, the AMOC curve is using multiple models to derive AMO from northern hemisphere temperature changes, there are average values that smooth the curve over decadal scales, so the break points are not clearly defined but it is clear that they fit the emission profile breakpoints very well (as do the other metrics that I posted above).


For example, Mann and Emanuel [2006]
show that such a procedure misattributes at least part of the forced cooling of the NH
by anthropogenic aerosols during the 1950s-1970s (especially over parts of the North
Atlantic) to the purported down-swing of an internal “AMO” oscillation. A number of
climate modeling studies support their finding [Santer et al, 2006; Booth et al, 2012;
©2014 American Geophysical Union. All rights reserved.
Evan, 2012; Dunstone et al, 2013], though the precise role that anthropogenic
aerosols have played in recent decades continues to be debated in the literature [Koch
et al, 2011; Carslaw et al, 2013; Stevens, 2013].

When they detrended forcing for AMO oscillation using CMIP5 they used a model mean that largely did not include secondary cloud effects.

thus their AMO trend below still fits the anthropogenic aerosol emission curve very well.

Jai, your second paper (Bellomo et al 2016) seems to deal mostly with cloud effects over the tropics:

From these experiments we conclude that cloud feedbacks can account for 10% to 31% of the observed SST anomalies associated with the AMO over the tropics.

I'm not sure yet how much that has to do with aerosols and the 30's-40's temperature bump in the Arctic.

The Ding paper does not mention this bump because they assume that it is natural variability, as does the IPCC.

The translation of tropical circulation impacts in the arctic is the fundamental work of the paper.  There are also many other papers that indicate the linkage between aerosol emissions and tropical water vapor, high troposphere humidity, PDO, NAO and even AMOC circulation changes.  In addition, the sudden drop in sea levels at that time (1920-1928 see image below) also indicates a significant increase in tropical precipitation on land. 

This paper from 2002

The present results, combined with this earlier finding, suggest that the indirect effects of anthropogenic sulfate may have contributed to the Sahelian drying trend. More generally, it is concluded that spatially varying aerosol-related forcing (both direct and indirect) can substantially alter low-latitude circulation and rainfall.

This paper in 2016

For the sstClimAerosol simulation, the cloud albedo effect contributes significantly to the changes in land surface temperature and precipitation pattern (Fig S6).

Note: TL in the image below shows changes in tropic land precipitation expected for a large increase in aerosols.

Also attached image S6 from the supplementary information showing full aerosol modeling with extreme reductions in tropic land rainfall due to an increase in Aerosols (and by reason a large relative increase from a reduction in aerosols).


The transition from a desert to a maritime climate happened in late December 2015.

Based on what? On some plumes of humidity over the Arctic? You don't know if that is an annual variation, or decadal, or what. You know as much as I do or any around (except maybe the owner of the site, Rob, Dr. Ding and a handful more), which is nothing.

Based on a graph???? Lol. Based on clairvoyance, a vision in dreams or what?

The primary indicator of a global atmospheric transition at that time:

Water Vapor Anomaly

Figure 1 Attached

But I believe there was a clear step change in November/December 2016 (I don't see anything special happening in December 2015, though)


In summary, our results are supportive of the hypothesis that cloud feedbacks favor the persistence of SST anomalies in the tropics via the WES feedback. By detrending the cloud observations, we roughly removed the influence of greenhouse gases. However, we have not examined the possible role of aerosol-cloud interactions on driving phase shifts of the AMO [Booth et al., 2012], which remains an open question.


I doubt that the 30s-40s temperature bump had much to do with aerosols.
The AMO is a much more likely candidate.

Here we use a state-  of-the-art earth system climate model, to show that aerosol emissions and periods of volcanic activity explains 76% of the simulated multidecadal variance in
detrended 1860 to 2005 North Atlantic SST. After 1950 simulated variability is
within observational estimates; from 1910-1940 our estimates capture twice the
warming of previous generation models, but do not explain the entire observed
trend. Other processes, such as ocean circulation, may also have contributed to
early 20th century variability. Mechanistically, we find that inclusion of aerosol cloud
microphysical effects, rarely included within previous multi-models
ensembles, dominates the magnitude (80%) and spatial pattern of the total
surface aerosol forcing in the North Atlantic.

Consequences / Re: Conservative Scientists & its Consequences
« on: April 20, 2017, 06:08:45 AM »
They also used references that differed from their own projections for aerosols, neglecting to include the absent impact of upper tropospheric cooling from aerosols and the resultant LR/WV feedbacks associated with aerosol reduction.  In addition, their energy constraints exempted 95% of the model runs and their period of study (mid 2000s) included the period of time when China increased their aerosol emissions to levels (globally) not seen since the early 1970s.


But you seem to be saying that to match the pattern of global temperatures, there needs to be an early 1920s dip in albedo increasing aerosols if I understand correctly?

No, I am saying that the global circulation impacts pointed to a significant reduction at this time, I looked at the available data and it shows a post WWI recession that was global in nature and, including a massive drop in the most productive economy at that time (Germany) showed that I was reading the PDO, AMO, AMOC and NAO transition correctly.

it is still a good indication,

U.S. and UK consumption patters also follow the similar trend shown here:

In addition, the real powerhouse of the time was Germany who in post WWI the Versailles Treaty had a massive hyperinflation and collapsed economy.

Consequences / Re: Global Surface Air Temperatures
« on: April 19, 2017, 07:11:35 PM »

do you mean above ground nuclear testing? the purpose of below ground is to prevent atmospheric impacts.  I would have to look at it but my sense is that the amount is insignificant compared to global coal emissions at that time.

the spike in global wood fuel in the post world war I recession and 1920 depression indicates that, from an energy use perspective, its effects was much greater than the great depression from an aerosols perspective.  The sudden change of aerosol emissions driven by economic cycles is the only variable that has the potential to impact the global circulation patterns on such a short time scale.  I made a hypothesis that the shifts happened before the great depression (in the 1920's) and I was able to find out that indeed, the aerosol emission shift actually happened during that time - as opposed to what I had believed previously.

Also that the shift in PDO to positive indicated that there was significant forcing pent up in the system, which causes a sudden shift in atmospheric and ocean circulations when the cork is released by suddenly cutting aerosol emissions.  In a Dynamic Fluid system when this happens there is always an impact that swings far beyond equilibrium.  Hence a definitive signal can be derived from the period.  AND since recent studies all indicate aerosol impacts to these circulation metrics (AMO, AMOC, PDO, NAO) it can be reasonably deduced that a significant part of what was considered 'natural variability' at the time was actually driven by regional SO2 emissions reductions and GHG forcing -- contrary to the current assumption that we cannot determine the cause of early period warming by the IPCC.

indeed it does appear that the collapse in Coal consumption began pre-1920.

There is also a PDO and AMOC pattern that follows the AMO and -NAO.

I know of only one variable that could possibly produce impacts to all of these. 


1st image AMO and NAO
2nd image AMOC
3rd image PDO

the All metrics show a systemic change beginning in the early 1920s.   

These graphs clearly show (to me) that the GHG forcing driver was present, significant and starting the shift toward +PDO, Stronger Trades (AMO) and positive NAO. 

Jai, Planning on further increases in total emissions to 1000 Gt or more is likely or worse inevitable.
I still think there is uncertainty in whether current anthropogenic emission trends or feedbacks are feeding CO2 atmospheric levels. Probably some of each. Rboyd posted a EIA revision in China's contributions that illustrates our problems with parsing out anthro from feedbacks.

"Energy-content-based coal consumption from 2000 to 2013 is up to 14% higher than previously reported, while coal production is up to 7% higher"

We should assume other countries fudge their emission figures as well and any reports of a flattening of anthro CO2 is premature. If on the other hand feedbacks are in majority the reason we see continued atmospheric CO2 increases the 1000 Gt number may far short of what is necessary to somehow drawdown, whenever we figure out how to do so.
 I also agree the ocean will give back what CO2 it has absorbed but the timeframe of that release may be in the thousand year timeframe. Remember also that the ocean has more ability to hold CO2 at cold temperatures so as we heat the oceans they will actually return more CO2 than what it has absorbed .
The amount of the return from the oceans is dependent on the gas partial pressure difference  between the ocean and the atmosphere like you stated.


thank you for posting that EIA bit.  I was looking for it yesterday.  There is some discussion that the drop in per unit coal consumption but the continuity of energy use from coal is a strong indicator of China moving toward cleaner coal types and processes as part of their 3-year aggressive aerosol reduction program.

The projections are not showing what is happening today but the expectation is that this process is ramping up significantly and the apparent results since December 2015 appear to be MASSIVE on a global atmospheric circulation scale.

Policy and solutions / Re: Renewables Reach a Tipping Point...
« on: April 18, 2017, 09:02:58 PM »
Not sure if I posted this elsewhere but this video on disruptive technologies is a MUST to see.

Clean Disruption - Why Energy & Transportation will be Obsolete by 2030 - Oslo, March 2016


It really depends on our emission scenarios, we are currently emitting about 10 Pg of Carbon per year with much of this going into the oceans.  As we draw down below 400 ppmv the oceans will begin return this Carbon to the atmosphere.  Also, between now and 2100 I expect an additional 300 Pg from carbon cycle feedbacks.  Of course the 1,000 Pg estimate is a rough one and based on what we do in emissions between now and 2050.

If we reach 4C the 1,000Pg of Carbon will be a gross underestimation due to the release of the same amount of carbon from global permafrost alone (over the next 200 years).


The time span between first and last years with < 1X 10^6 km^2 may not be as narrow as you think.  (I am not saying that you are wrong on this - just that they are different questions).

In retrospect, you are right.  I was being far too conservative for conservatism's sake.   Interesting, you caught me self-censoring my answer.  changed from 2040-2050 to 2030-2040.


The current C stock in the world’s forests is estimated to be 861 +/- 66 Pg C  -  we need to drawdown 1,000 Pg of C


you are probably right.

the discussion about the pure-time discount rate for multi-generational accounting of the social cost of carbon assumes that future generations will have more technical and societal capability to alleviate these massive impacts.  In the event that the opposite is true, that the fight against societal collapse, adaptation AND the need to implement technical solutions to combat global carbon cycle feedbacks and reduce atmospheric CO2 to 350 ppmv will take more resource than is available would demand a NEGATIVE discount rate. 

but there is hope that a global climate 'pearl harbor' event will shift the global focus to address this global threat to humanity in the next 10 years, with a rational response. 

I understand your pessimism.

Consequences / Re: Global Surface Air Temperatures
« on: April 17, 2017, 05:42:29 PM »
I have a check-in with skeptical sciences that we will be sitting at +1.5C above pre-industrial for the 12-month average ending in May 2018.


Global precipitation is reduced by around 4.5%, and significant reductions occur over monsoonal land regions: East Asia (6%), South Africa (5%), North America (7%), and South America (6%).

Science / Re: 2017 Mauna Loa CO2
« on: April 17, 2017, 05:24:53 PM »
carbon cycle feedbacks

Arctic sea ice / Re: The 2017 melting season
« on: April 17, 2017, 05:14:21 PM »
The Beaufort sea is still slightly below last year's record breakup for this day of the melt season.  It should be noted that the Beaufort had many sections of >3+ year ice still remaining (remember 'big block'?) 

There were greater wind events last year and (I suspect) the wind profile for the older ice was more condusive to breakup.  The overwhelming amount of thinner, younger ice in this year's beaufort sea is much more poised to meltout than last year even though the dispersion is (slightly) greater.

Dr. Ding has just posted a reference to a paper (Armour et al 2011) that posits - based on model simulations - the total reversibility of the observed loss of Arctic sea ice*, if we just remove CO2 from the atmosphere as fast as we have added it (by what means is not specified, but refer to the "geoengineering activities" jai mitchell mentions above).

* >80% loss of September Arctic sea ice volume in < 40 years, according to Axel Schweiger, one of Dr. Ding's co-authors in the latest Ding et al paper on natural variability attribution.

Personally, I think anyone that voted anything other than 2020-2030 in the poll above is a denialist, consciously or not.

jai mitchell, you posted a link to a YouTube video of a Kevin Anderson interview during COP21. At 9 minutes there is his opinion on negative emissions (removal of CO2 from the atmosphere). Needless to say, I agree with Kevin Anderson on all the points he makes during that interview. Basically, relying on future negative emissions (for which the technology does NOT exist), or on a carbon budget (which we have exhausted a long time ago), or on "natural variability" that is supposed to bring a comeback of Arctic sea ice, are all distractions and wishful thinking.

This is the reality of CO2 atmospheric concentration, and there is no denying it:


Negative emission technology does indeed exist, however I was referring to global atmospheric dimming as a geoengineering stopgap to 4C above.

The methods are: 1. reforestation, 2. agricultural practice shifts and 3. industrial processes that remove CO2 from the atmosphere.

reforestation and agricultural practices do not have the capability to remove CO2 fast enough so industrial activities must be engaged.  However there are chemical and technical processes for removing CO2 they do not exist are not currently in operation because we do not have a reimbursement mechanism to make them worthwhile.  I believe it would take a cost of carbon over $1,000 per metric tonne. 

It will take over 80 years to remove the CO2 needed to restore a stable climate regime.  and yes, the Sea ice will come back if we do. 

there is roughly a 20% chance per year, cumulative year-on-year over the next 5 years that we will have our first effective ice free September.

This thread is dead

The top two authors on this paper both believe that the FIRST < 1X10^6 km^2 SIE September minimum will happen around 2065.  Or, this is what they have said publicly.  Whether they ACTUALLY believe this is not clear.

The difference between SIE effectively ice free in 2020-ish vs. 2060-ish is measured in the balance of millions of human lives.

There is no excuse for being this far removed from reality.  Either they are completely incompetent, unaware, overconfident in their supposed knowledge, don't care or are a fifth column element working against the greater good intentionally.

In any case these errors will soon be written in stone as one of the greatest failures in human history.

if there is anyone left to remember.

The most intriguing part of that event is that warming exhibited a pretty large scale feature in the Arctic and the area was warmed by something very fast from 1920s to 1930s.  So causes  of this fast warming rate has puzzled me for a long time.

Reduction in global SO2 emissions

Any current climate scientist who expects the first summer effective ice free date between 2065 and 2115 had better start writing their contribution to the 'mea culpa to humanity and the world' for the AR6 and get ready to start advocating for a WWII mobilization emissions reduction process using non-market forces with total societal mobilization requiring ~1/3 of global GNP per year for 10 years to get to net zero emissions, since his/her obvious over conservatism has directly contributed to the potential collapse of human civilization as a result of mis-communicated risk impacts to policymakers.

Dr T.

The discussion is about SO2 emissions and their impacts on what we have previously called 'natural variability'.

in industrial applications coal typically burn at 1350C and some more efficient high-temp pulverized coal power plants operate at 1500-1700C.

open burning of coal in a home fire box typically burns at 600C (at most).

In addition, larger volumes of smokestack emissions allows for greater plume resistance to dispersal and higher altitude atmospheric loading. 

note that the coal smokestacks that we see with white steam coming out are cooled during the scrubbing process to remove (most of) the sulfite.  Non-scrubbed smokestack emissions are clear and very very fast.


I wonder if the global recession beginning in 1929 could be to blame for the spike in Arctic temperatures? Similar to what we are seeing as China winds down its dirtiest pollutants.

it should be noted that coal was a common heating fuel during this time and that the reduction of coal use during this time was predominantly in higher temperature processes (rail transport and steel production).  These higher temperature emissions appear to have a much greater impact than lower-temperature combustion products that stay much lower in the atmosphere (and rain out much sooner).

jai mitchell  +1

I've been meaning to say this for a while, and this is offtopic, but your coal/aerosols/sst argument is a courageous one. You are saying that shutting down Coal plants causes short term global warming.  I bet you get a lot of flak for that.

When you first started to state that point, I was suspicious of you because it sounded like a very convenient argument for a climate change denier to take advantage of. But then as you refined the argument and presented more and more evidence I realized that my suspicions of your argument  were nothing but my own personal bias. You are probably right and your argument is very important if coal is going to be phased out.

For example phasing out coal plants during warm cycles of the planet will compound the problems of the warming. Closing them during cool earth cycles will reduce the impact of the short term warming at the cost of maintaining the Earth at a higher temperatures for longer.

This might be an important consideration that is impossible to talk about because of the nature of the debate.

thanks Arch. 

you know the real issue here is that a significant (possibly VERY significant) portion of the cooling impact of upper troposphere SO2 is simply not addressed in the climate models since the physical interactions are not well known. 

With only a modest addition of these impacts and with the recently documented impacts to PDO, AMO and related atmospheric circulation patterns (based on regional emissions/reduction trends in the modern record) much of the supposed variability is washed out INCLUDING the early warming phase in the 1930s that is currently NOT being 100% assigned to anthropogenic activity (just like the intensity of PDO/AMO was also missing significant anthropogenic components).

However some interesting things happen when you work from this assumption that SO2 impacts are severely understated.

1.  The Ruddiman early agriculture hypothesis is proven correct
2.  Arctic sea ice is going to disappear in the next few years (summer minimum)
3.  ECS is closer to 5.5K/2X CO2
4.  we have locked in +3.5C at current atmospheric abundances
5.  We have to start right away with a WWII scale mobilization effort to radically eliminate all fossil fuel consumption in the next 10 years AND begin large scale BEECS/Biochar/Regenerative Agriculture to offset carbon cycle emissions to prevent going over +4C and possibly losing global modernity.

#421 on: Today at 11:11:11 PM »

thought this timestamp was pretty cool.

there are two ways to post an image here: 

1.  click the + attachments and other options button below the data entry screen and upload as an attachment (note large files will not be auto sized so >450px will be larger than the viewing window or

2.  click the 'image link' button (second from the left) above the data entry window and add the image url as a link to show in your post.

just for the record:

ASLR:  very astute but you are neglecting aerosol forcing,  If we completely halt aerosol emissions in 2027 then I am likely to agree that 2028 will reach +2.7C but under current conditions, with moderate reductions in aerosol emissions, continued significant anthropogenic carbon emissions and rapid sea ice-albedo feedback, I still expect (conservatively) to move above +2C by 2036.

When the data is highly variable, assigning future projections to either exponential or gompertz trends is simply a matter of confirmation bias.

It is much more likely that the 2013/2014 anomalous years were black swan events that will not be duplicated.  The Ridiculously Resilient Ridge and the massive and persistent Negative PNA index values for that period stand distinctly apart from the historic trend.

Pithan & Mauritsen 2014 on Arctic amplification:

(1) Changes in atmospheric heat transport dampen intermodel spread because they are more positive in models with little Arctic warming. This is consistent with results from an energy balance model used to reconstruct warming and transport changes in the Coupled Model Intercomparison Project Phase 3

(2) In the ensemble mean, atmospheric heat transport does contribute to Arctic amplification by enhancing Arctic and reducing tropical warming (Fig. 2a). Contrary to physical intuition, poleward atmospheric energy transport does not scale with the meridional temperature gradient within individual models, but increases in most models despite a reduction in the Equator-to-pole temperature gradient.

Hind et al 2016:

(3) "Uncertainty in the estimated range of the Arctic amplification factor using the latest global climate models and climate forcing scenarios is expanded upon and shown to be greater than previously demonstrated for future climate projections, particularly using forcing scenarios with lower concentrations of greenhouse gases...

On the other hand, for the RCP2.6 simulated future scenarios an Arctic amplification factor of less than 1 or even negative values are quite possible. In other words, the Arctic region may be able to undergo temperature changes in opposition to the direction of any global changes if the global radiative forcing follows the RCP2.6 pathway. It generally seems as though the uncertainty bounds calculated for future projected Arctic amplification factors indicate that higher numbered RCP forcing experiments (analogous to higher greenhouse gas concentrations) show less uncertainty than the lower RCP experiments. This is perhaps not an unexpected result given that higher greenhouse gas forcings would be expected to increasingly overcome differences in the physical models and internal climate variability."

(1) models with greater arctic amplification result in lower amounts of mid-latitude latent heat intrusion, models with lower arctic amplification result in higher amounts.  this is because the models expect (are designed to show) atmospheric circulation changes as a result of the  temperature gradient changes produced by a globally averaged forcing and regional (but slow) feedbacks.

(2) In the model mean, the primary force for meridional transport is the temperature gradient, however other circulation changes (feedbacks) bias the mean somewhat so that the amount is slightly greater than the rate of change of the meridional temperature gradient (not scaled).

(3) These results show that the model mean is dominated by GCMs that do not allow for tropical anthropogenic aerosol emission reductions to significantly increase regional Tropopause heights, with increased regional water vapor and lapse rate feedbacks.  The resulting changes in the Tropic geopotential height gradient will produce rapid expansions of the ITCZ, a significant expansion of the Hadley Cell, the greatly increased export of mid-altitude water vapor pulses in the form of atmospheric rivers, the strengthening of (slowing/standing - even short reversal!) Rossby wave activity (due to extreme upper latitude blocking events) that will eventually result in tropical wave/pulse formations that are unprecedented in scope and scale since the early Pliocene.

---  This makes me think that it is time to do a more rigorous  means testing of the climate models as qualification for inclusion in the CMIP6 and drop about 1/2 of them from the ensemble --- as harsh as this would be to the people who have worked incredibly hard on them, we simply cannot let these poor performers continue to bias the ensemble results anymore.

Arctic sea ice / Re: The 2017 melting season
« on: April 15, 2017, 02:44:05 PM »
this is rather laborious, I made screenshots in approx 4 day steps, tracking backwards by frequent toggling layers in GIMP as recommended by A-team some while back
Nice work, glad to see some of A-team's data visualization expertise percolating through the forum.

I remember he was talking about a GIMP extension that helped make these animations. 

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