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Messages - crandles

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Science / Re: 2019 Mauna Loa CO2 levels
« on: May 07, 2019, 02:21:43 PM »
See reply #122 from dbarce, their was a correction in the measurement, and 4.48 does not stand.

Actually it is Scripps (measure posted on daily measure of 415.09 for May 3rd that does not stand. The 4.48 is the weekly difference shown on ESRL:
Week beginning on April 28, 2019:     414.32 ppm
Weekly value from 1 year ago:     409.84 ppm

AFAIK that 4.48 still stands.

Definite up and down spikes in 2018 on ESRL whereas 2019 looks noisy over long period:

Science / Re: 2019 Mauna Loa CO2 levels
« on: May 04, 2019, 06:30:41 PM »
Highest couple two of three highest days ever recorded:

May 03:     414.81 ppm
May 02:     Unavailable
May 01:     414.88 ppm
April 30:     414.52 ppm
April 29:     Unavailable

(other one is
March 18:     414.84 ppm)

Policy and solutions / Re: Tesla glory/failure
« on: May 01, 2019, 02:27:25 PM »
But we’re still hoping for an East Coast gigafactory, soon!

Sigmetnow 'identifies' herself as 'Tesla'? Tesla is a car manufacturer. It's 'a thing', a corporation. It's not a 'religion' led by a Yogi.

We could be an east coast business development group, or an environmental group (albeit with perhaps a bit of green BAU which you don't like) or Sigmetnow plus spouse or .....

It seems to me that you are rushing to denounce this without stopping and figuring out what it means let alone whether you should denounce it.

Arctic sea ice / Re: Latest PIOMAS update (April 2019)
« on: April 16, 2019, 05:35:13 PM »

Arguing in the PIOMAS thread about the future of Arctic sea ice with reference to extent models?

Anyway, here is a volume graph that hasn't seen the light of day for a bit.

A cubic equation that indicates a slight increase from 2024 and will later quickly shoot upwards? Seems a odd thing to include with that criticism.

Yes there is an issue with showing extent graphs to demonstrate expected volume trend. But does it undermine my point?

If volume loses maintained linear loss rate, then extent graphs would have to show accelerating rate of loss to catch up. However if extent graphs show declining rate of decline then volume graph will have to slow down more sharply. So I think the difference between volume and extent strengthens my point.

The other point: Picking one particular model and saying step changes at these points seems a poor method compared with looking at shape from many models. This also seems to survive.

But I will admit this is getting off topic, more suited to 'when ice free'.

The rest / Re: Brexit...
« on: April 12, 2019, 07:54:34 PM »
So, as a thoroughly pro-Remain Brit

Sensible chap :)

How much of a shambles is needed before it is decided that current views of current electorate should be considered?

While I voted remain and remain firmly pro remain, I don't really have any good argument why my position should be treated any more favourably than someone else's views from the other side. Also I don't hear of many people changing views from leave to remain. However, I think there must be lots who abstained who would now vote remain to end this shambles as soon as possible and people who voted leave that might think it is such a shambles that they would abstain.

I consider not consulting people again something like 3.5 years later when there is much more info on how it is going to be more serious abuse of democracy than the problem of failing to honour result of first referendum.

VW CEO confirms the group’s brands will introduce 20 new electric vehicles by the end of the decade

Wait, what? If he says "end of this decade" does he mean this year? Then why not say "this year"?

Or is he talking about the next decade? 20 EV cars by 2029 would be laughable.

I'm confused.

dated ~27 Jan 2016

Antarctica / Re: Halley base shut down and new crack in Brunt shelf
« on: March 07, 2019, 04:38:19 PM »
Looks like crack might be complete at resolution shown.

Zooming in a little more, I am not even sure of the cracks marked with lines drawn above and or right of feature. Is interpreting more cracks justified?

Science / Re: 2019 Mauna Loa CO2 levels
« on: February 18, 2019, 01:27:37 PM »
What do you think it is supposed to mean?

We have had wild daily swings before, typically? high readings (or is it almost always? or even always) and they have always settled down again. We have an unusually large number: 6 (maybe 8?) of them in the last month or so compared with 1 in Feb 2018. I don't think we should let a few odd readings cause us to panic. If it settles 'up' to give consistent readings above 4ppm above the previous year then that would be genuine cause for increased concern and/or investigation.

I am expecting upward drift due to El Nino to values higher than 2.5ppm per year. 2.5ppm per year +- a bit with ENSO clearly gives us a GW problem certainly cause for concern. However, suggesting it could go to 5ppm sounded like inappropriate panic, and some keep calm and don't get carried away with a few wildly variable data points words seemed appropriate.

Environmentalists screaming the end of the world is nigh then it turns out to be a bit of variable data just makes the general population react by saying those environmentalists are always crying wolf and are increasingly likely to dismiss environmentalist views. So it is a bad idea and doesn't help the cause.

Policy and solutions / Re: Tesla glory/failure
« on: January 30, 2019, 11:36:01 PM »
I've been trying to get my head around this.  Just over 12 months ago Tesla had a workforce of 33,000 and before the latest cuts had a workforce of 45,000.  So a net gain of 9,000 after all the cuts.

The amount of talk over production line inefficiencies leads me to think that as they are ironed out then less staff are required to cover for the failure of the automation.  I suspect this round of cuts wont reduce production, but they are still a long way off targets.

The labor hours per Model 3 vehicle declined yet again by roughly 20% compared to Q3 and by about 65% in the second half of 2018 alone.

Antarctica / Re: PIG has calved
« on: January 20, 2019, 09:14:45 PM »
Not sure I would trust me if I were to try tracing the line. Not sure if that ice front date is 1907, 1927 or 1937. Ice front perhaps is similar to 1972-2016. 2018 moved more, however bay seems to have widened??

Arctic sea ice / Re: "Stupid" Questions :o
« on: January 19, 2019, 12:57:17 PM »
If ppm of C02 are increasing in the atmosphere, that must mean ppm of something else is declining. What other atmospheric gas is declining as CO2 increases, and does this need for something else to decline at all effect the rate of growth of CO2 ppm in the atmosphere?

Carbon in fossil fuels are burned(oxidised) to create CO2, so it is O2 in atmosphere that is declining. The effect on O2 in the atmosphere is negligible:

CO2  280 ppm  -> 410ppm (46% change)
O2 209590ppm -> 209460ppm (0.06% change i.e. you experience more effect of less oxygen at top of small hill than at bottom)

Obviously this change in O2 hardly makes any difference to the ability to burn fossil fuels.

Edit ppm typos

Policy and solutions / Re: Tesla glory/failure
« on: January 06, 2019, 02:54:54 PM »

Breaking:  Elon Musk’s plane (flight plan) spotted heading to Shanghai.
Possible groundbreaking ceremony for Gigafactory 3? 
Months ahead of schedule, if so….

How long does it take to put up a tent?  ;)

Policy and solutions / Re: Renewable Energy
« on: November 23, 2018, 11:57:44 PM »

2018 UPDATE of my series about @IEA versus reality in solar PV

Once again reality is steeply increasing
and once again the IEA is having none of it

Don't these guys ever learn?
This has been going on since 2002
Seems their models simply can't conceive of exponential growth

Antarctica / Re: PIG has calved
« on: November 09, 2018, 04:45:20 PM »
That image is fig 2a (showing PIG) of the following paywalled reference, and the attached image is fig 2b for Thwaites.  As I am too cheap to purchase this paper, the images come from sidd, but these images make it clear that the red line shows the local grounding line and the yellow line shows some short of time averaged (from 2009 to 2014) position for the ice face of the associated ice shelves (note the dotted yellow line across the active calving front for the Pine Island Ice Shelf, PIIS, indicating that this ice face was actively shifting during the 2009 to 2014 period).

Just enter paper name into

and you get

New bathymetry of the Amundsen Sea Embayment (ASE) of West Antarctica with
the a) Pine Island, b) Thwaites/Haynes and c) Smith/Kohler glaciers. Grounding line positions
are red (year 1996), ice front positions (year 2008) are yellow, AUV tracks are green, and seismic
data are black crosses. Bed elevation is color coded from brown/yellow and green (above sea
level) to light blue and dark blue (-1,400 m), with light contours every 100 m and thick contours
every 400 m. Profiles A-A’ to F-F’ in orange with dots every 10 km are shown in Figure 3.

Consequences / Re: Global Surface Air Temperatures
« on: October 24, 2018, 12:19:58 AM »
I did read that a "change of just 1% to the Earth's albedo has a radiative effect of 3.4 Wm-2, comparable to the forcing from a doubling of carbon dioxide"

No idea where the number comes from unfortunately.

But I did some quick math. Surface Area of the Earth is 510,064,472 km2. 1% change would be 5,100,644.72 km2.

The 2000-2009 avg. for summer minimum sea ice in the arctic drops 968,139 km2 from the 79-99 avg (almost .2%).

The 2010-2018 avg drops 2,040,500 km2 from the 79-99 avg (~0.4% change in earth surface) giving, 1.36 Wm-2 difference

See the graph I've attached.

Of course it probably doesn't work like that (with a linear relationship to the amount of forcing), and I do know that this doesn't account for what the rest of the earth’s albedo change was during that time, and that the change in albedo would only be during a few summer months...

Still I wanted to offer up these back of the envelope calculations, since if I’m lucky enough to receive any criticism, it will be quite the education for me and probably some other lurkers.

I probably ought to be able to offer more and better constructive criticism but FWIW:

Average albedo of Earth is roughly about 0.3
whereas Arctic figures vary see

If we say snow and ice average 0.57 and open water looks like about 0.07 then you have a change in albedo of around 0.5. So perhaps your figures are a further factor of two from explaining the size of the effect.

I think your numbers are correctly telling you that arctic sea ice retreat is not hugely significant. I think land areas formerly covered by snow may well reveal larger numbers. Rutgers has some numbers if you want to play with them.

Consequences / Re: Global Surface Air Temperatures
« on: October 23, 2018, 11:56:42 PM »
Lagged temperature effect following ENSO is such that we are likely near a global temperature minimum even if it hasn't already been reached.

Still it is clear the last La Nina was pretty weak so it does seem dubious to connect strong La Nina minimum to weak La Nina minimum.

I think Hansen is getting a bit carried away with talk of more than a doubling in rate. If there was valid reason for doubling of the rate over just a few short years, why has the temperature record from 1970 to date looked pretty much like a straight line?

I wouldn't be surprised if Hansen does publish a paper claiming acceleration in rate is now detected. However if this happens then I would predict that this detection will be of a very weak acceleration not anything anywhere near a doubling in rate.

Policy and solutions / Re: Tesla glory/failure
« on: September 15, 2018, 02:49:59 PM »

Other miscellaneous comments showed Shotwell at her best, ad-libbing one-liners that were lucid, accurate, and entertaining.

“We’ll be going to Mars … with NASA and with ESA. It’s gonna be like extreme camping… for 100 years. And then it might be okay.”
“[Space] tourism is inevitable but [SpaceX] doesn’t want to do it too soon”, the goal is to launch “test pilots before families”
“The first cars on Mars will be Teslas.”

Someone's confident Tesla will survive a few years  ;)

Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: September 08, 2018, 04:00:12 PM »
I believe (and correct me if I am wrong) that this exercise is just curve fitting to the best possible line.  What we lack (me included) is an explanation as to why any particular fit should be chosen.  Oftentimes, a linear fit can approximate a particular data curve over a specified range.  As the data approaches zero, I would expect this to fail, although in which direction is debatable.  In an unknown situation, oftentimes a moving average can best define the trend, as it incorporates recent data, without bias.  Not that it is any more accurate, but it tends to smooth out the data, removing variations which may mislead the eye.  Lastly, extrapolated beyond known parameters is always highly speculative, as we do not know how that affects the environment.  In short, it is a guess.  But we strive to make it the most educated best possible, and your guess may be different than mine, depending on which parameters we each feel might predominate in a future scenario.

Yes it is highly speculative.

>What we lack (me included) is an explanation as to why any particular fit should be chosen.

I try to refer to the models and if they almost all show a Gompertz like shape, then why would you use a different shaped curve to fit the data? A better fit might be one reason but if this gompertz shape does pretty well at reducing the RMSE that seems additional reason to go with it.

Use too many parameters and you can get a better fit and send the extrapolation off in any direction you choose. Hence it is necessary to try to minimise the number of parameters used. This can be considered to be a form of Occam's razor - if you don't need extra complexity to explain the data then that extra complexity is likely just wrong and should be omitted.

These considerations (particularly considering the physics which is what the models do) tends to act to place some limits on where the extrapolation goes.

Yes, it is highly speculative and the more so the further you go away from the known data. But at least it is based on something. If the alternative is making stuff up off the top of your head, and the people doing that sort of thing tend to be concerned about the issue and therefore likely to give a biased view towards catastrophic effects in order to motivate action,.... guess which I think should be preferred?

Arctic sea ice / Re: Holy Sh!t: Year-Round Arctic BOE Imminent
« on: September 07, 2018, 11:44:11 PM »
The lead article states that there is already enough heat in the lower, saltier layer to melt all of the ice in the region throughout most of the year.

A one off quantity of heat that may well be enough to melt all the ice. But what would happen to the heat budget? Surely that would be massively affected with the water venting huge amounts of extra heat each winter due to lack of ice/much thinner ice for it to pass through. After venting this heat burb, would the ice return to normal levels over the next 2 or 3 years? Oh yes, there is the salt as well; but ice formed is relatively fresh by expelling cold briny water which then sinks. So this returns the salt to lower levels. Maybe the salt distribution takes a bit longer to return to something close to recent distribution.

I wouldn't want to risk carrying out this experiment even if I was a lot more confident that nothing particularly dramatic happens and soon returns to normal because even a small chance of something dramatic should be avoided if possible. But we are doing the experiment and so we have to live with the risk. However, I don't see that it makes sense to assume the likely consequences are catastrophic or that the chance of something dramatic happening is more than a low chance. If experts thought there was a high chance of something catastrophic then they would be clearly and loudly saying so.

AIUI the suggestion was that the mixing only occurs to significant extent at the edges of the continental shelves rather than all over the Arctic ocean. Elsewhere the stratification is really rather stable. Yes, changes are happening and eventually this will cause other changes but we don't really know whether this will be slow, fast, only in some locations, or over wide areas, or...

Arctic sea ice / Re: Holy Sh!t: Year-Round Arctic BOE Imminent
« on: September 05, 2018, 01:50:10 AM »
It's a good question how long to go before you can establish a trend, in this case. In most cases for climate you need decades. This certainly does not meet that standard.
*Exactly*,  and thank uou.

Decades is about establishing a reliable number for a trend i.e. a number. Steepening or flattening is a binary choice. That is a different ball game. 2^11 = 2048. No, I agree that doesn't really work, I believe there is much more than a 1 in 2048 chance of the trend now steepening. However, maybe that is about the future which is hard whereas this is about observations to date.

If there were only 6 years after inflection point, I would believe that the process of fitting the curve was essentially data mining the residuals for an overfit of the data. So it appears to me to be more like 2^(11-6)=32 and 31/32 is more than a 95% confidence level but only a little more.

Perhaps better than guessing that number 6 used above, instead model a linear downward trend with noise to match the data 200 times. What would the 10 5 percentile model that is best at showing a slowdown in the rate look like? Would it be more or less convincing than my graph?

Waiting 20 or 30 years data before declaring whether the trend is flattening appears to me to be misuse of the valid reason for wanting that much data to get a reliable trend rate number.

(Edit: I meant 5 percentile or 10th most flattening data set)

Arctic sea ice / Re: Holy Sh!t: Year-Round Arctic BOE Imminent
« on: September 04, 2018, 04:50:44 PM »

The point of looking for the natural extreme is to show the range of variability. 

Sure, that is sensible if that is what you want to do.

I don't believe the flat trend, so if BOE happened, more likely to be a bit of trend steepening and some natural variability.

Should we worry more about trend steepening than about it occurring due to variability? Possibly depends whether you expect serious consequences from a BOE that was just due to natural variability?

Arctic sea ice / Re: Holy Sh!t: Year-Round Arctic BOE Imminent
« on: September 04, 2018, 04:42:09 PM »
Increased GHG levels, increased water temperatures, increased air temperatures, any other forcings,  internal variability, and feedbacks both positive and negative.  That covers everything, right?   ;D

A few more considerations, ...

Natural / internal variability, hmmm. Is there any unnatural/external variability?  ;) ;D
Do aliens aiming meteors at the Arctic count as unnatural?  ;) ;D

Arctic sea ice / Re: Holy Sh!t: Year-Round Arctic BOE Imminent
« on: August 31, 2018, 01:43:33 PM »

In the coming years, however, excess BG halocline heat will give rise to enhanced upward heat fluxes year-round, creating compound effects on the system by slowing winter sea ice growth.

So even before the current layered structure of the Arctic has undergone the expected 'fundamental change,' the effects of this heat will be felt very soon, not decades or centuries, but in 'coming years.'

Am I misinterpreting something here?

What proportion of folks thinks this is new and/or only in 'coming years' as opposed to thinking this has contributed to upward heat flux over the last few years (or decades) and therefore already included in the trend of observations?

Just because this is being talked about in this way for the first time doesn't mean it hasn't been there in the observations.

Arctic sea ice / Re: Arctic Image of the Day
« on: August 28, 2018, 04:55:36 PM »
Come on, Treform2 has made 2 posts on this forum. (Treform posted not at all if you think it might be old member lost password and created new membership.) What sort of welcome to the forum is this? (Even if it is a mistake, it looks like an easy one to make.) Treform2 didn't even say it was obliterated.

Welcome to the forum Treform2. What you have received is not the normal welcome new members get.

If it hasn't collapsed then this should be pointed out, but I think there may be a different approach for a new member than the manner of the posts made here. I find the attitude shown to a new member distinctly uncomfortable.

Arctic sea ice / Re: "Stupid" Questions :o
« on: August 21, 2018, 03:57:21 PM »
I suspect I am in small minority to some extent agreeing with your deniers against the above posts.

I think there certainly is a negative feedback from more open water losing more heat. It certainly isn't the only feedback and I would suggest that in summer the albedo feedback is more important but in winter it is the open water losing more heat that is dominant.

The combination of these two major feedbacks means that heat is accumulated in the summer. Come fall and winter this extra heat is rapidly lost with the freeze up only having been delayed by a week or so, so far and this has little effect on the volume of ice at maximum.

So I think the negative heat loss feedback looks like it will be sufficiently dominant to stop the positive feedbacks creating a run away situation but it cannot reverse the situation already reached.

If you take a different view, how else do you explain the following sort of shapes apparently emerging? Why isn't it continuing to curve ever steeper if you think the positive feedbacks are dominant?

(Note I don't believe the flat trend, I think it will continue downwards while GHGs and ocean temps are rising.)

Policy and solutions / Re: Cars, cars and more cars. And trucks, and....
« on: August 21, 2018, 03:22:17 PM »
Re Graph of accounts payable.

This is a nice graph showing Tesla growth - the more they produce the greater accounts payable become. What does GSY think it shows?

If it was showing days to pay bills, a rising trend would be seriously worrying and lots of people would be talking about this and suppliers would be seriously unhappy/worried, but if they are saying they want to maintain or grow their business with Tesla, it appears they are not unhappy. Hence, it likely shows growth in production.

There is just way more motivated reasoning in GSY's posts than in what he calls Tesla fanboys posts. Posts are clearly provoking reaction. Is there any other name than troll for this?

Policy and solutions / Re: Cars, cars and more cars. And trucks, and....
« on: August 18, 2018, 12:38:42 PM »

It's not like fossil fuels would be outlawed, they would just be expensive. You could make tools, they would just be more expensive. And it would be outrageously expensive to make a car, or to power it, regardless of power source. Not everyone would have to would just be much more common. Food would just be much more local. Food that can be stably stored and transported probably would be still. Trains are incredibly efficient. Air travel would reduce 1000 fold. You think the year 1850 is nonsense, a fake time? Wouldn't we be much much better at farming and simple living with access to information and some more complex durable tools and materials. Modern technology doesn't just stop, it gets redirected toward leveraging historically normal human occupations. And energy consumption drops to less than 10% current levels, probably more like 1%. We are currently incredibly wasteful. Carbon negative farming is the only realistic option for reducing GHG levels. It is so ****ing stupid to instead cross our fingers and wait for some technology to save us so that we continue living lives which cause cancer and depress us.

Outrageously expensive? Yes, the cost would be higher due to a steep carbon tax (hopefully gently increased so as not to cause too much disruption on introduction), but what happens to the tax money? The government gives it back to the people by tax cuts and/or a basic income to everyone so people have more income to afford the higher prices. Average person with average income and average ff use and ability to switch to lower ff use is still able to afford similar lifestyle despite all prices increasing but ff heavy use items more than others. The rich would be more able to afford the investments like to install solar panels and purchase electric cars when they become available to keep their running costs down.

>"energy consumption drops to less than 10% current levels"
huh? Renewables already contribute like 20% of our energy consumption, why would energy consumption drop to 10% so that renewables are taken out of use??? Sounds like you are making it out to be a far more dramatic change than it needs to be.

Any suggestion we need to go back to the stone age or even just 1850 just makes the public turn off and think environmentalists are just nutters who want to stop the world because they want to get off.

(Of course it can go the other way too. If the recommendation is to use low energy light bulbs
then it can't be much of a problem. So judging it right can be difficult. However people seem to frequently be going over the top.)

Policy and solutions / Re: Cars, cars and more cars. And trucks, and....
« on: August 13, 2018, 05:13:11 PM »

Why did I say “funding secured”?
Going back almost two years, the Saudi Arabian sovereign wealth fund has approached me multiple times about taking Tesla private. They first met with me at the beginning of 2017 to express this interest because of the important need to diversify away from oil. They then held several additional meetings with me over the next year to reiterate this interest and to try to move forward with a going private transaction. Obviously, the Saudi sovereign fund has more than enough capital needed to execute on such a transaction.

Recently, after the Saudi fund bought almost 5% of Tesla stock through the public markets, they reached out to ask for another meeting. That meeting took place on July 31st. During the meeting, the Managing Director of the fund expressed regret that I had not moved forward previously on a going private transaction with them, and he strongly expressed his support for funding a going private transaction for Tesla at this time. I understood from him that no other decision makers were needed and that they were eager to proceed.

I left the July 31st meeting with no question that a deal with the Saudi sovereign fund could be closed, and that it was just a matter of getting the process moving. This is why I referred to “funding secured” in the August 7th announcement.

Anyone still think he is looking everywhere for investors?

Arctic sea ice / Re: "Stupid" Questions :o
« on: August 09, 2018, 01:46:10 PM »
Water vapour not in CO2e is a matter of causes or forcings vs consequences.

Average residency time of water in the atmosphere is about 11 days. So it adjusts its level very rapidly.

Warmer atmosphere means more water can be held in atmosphere and there is more water in the atmosphere. Generally relative humidity (on average over very large areas) stays fairly constant which means absolute humidity rises.

Note how this is a consequence of warmer temperature:

Adding steam to atmosphere just causes more rain somewhere to remove such an added water vapour effect before it has time to have any significant/noticeable greenhouse warming effect.

Warmer atmosphere however permanently keeps increased level of water vapour.

Thus water vapour is not a forcing, it is a consequence of warming so greenhouse effect of water vapour should be attributed to its causes which is other greenhouse gasses.

CO2e is looking at causes (forcings) not consequences therefore water vapour shouldn't be included in a measure of forcings.

Direct GW effect of doubling of CO2 without other effects like water vapour increase, snow reductions changing albedo (also cloud effects and lapse rate) is relatively easy to calculate and is around 1C per doubling. With these other feedback consequences it is much less certain but probably around 3C +/- 1.5C.

Policy and solutions / Re: Cars, cars and more cars. And trucks, and....
« on: August 08, 2018, 07:22:37 PM »
Yes, it was so out of the blue, that other directors said they had no clue about it


or they say they have been having meetings about it for last 6 days?

At some point info will leak so best to announce it in the way you want. Stock exchange rules allow you to use twitter or other social media provided you have told people which social media will be used. I don't see anyone suggesting Musk has done anything wrong.

>" floated the idea of going private on twitter out of the blue." Yeah right! NOT.

Policy and solutions / Re: Cars, cars and more cars. And trucks, and....
« on: August 08, 2018, 12:04:28 PM »
Investor support is confirmed. Only reason why this is not certain is that it’s contingent on a shareholder vote.

If you might need further finance, why do it?

This sends a signal that the management is confident of their position that they don't need further finance.

Arctic sea ice / Re: "Stupid" Questions :o
« on: August 08, 2018, 01:37:01 AM »
One thing that bothers me deeply is the lack of discussion regarding the entirety of GHGs' current effects. Typically only CO2 is discussed, and methane is mentioned as some sort of slight addition and a possible problem if permafrost rapidly thaws.

When methane is discussed it is almost never done with reference to the current forcing from CH4 levels. The 20, 50, and 100 year effective warming potentials are very important, but that is not what effects climate this year or next year or the year after. Methane's lifespan is like a decade, so even 20 year effect drastically understates the warming relative to the current effect.

This is something that also bugs me and I look forward to seeing an answer.  I suspect a proper analysis will include the earth's spectral radiation plot as measured from space, a la :

I would like to see a proper answer too.

What I take from the following image:

is that one of the CO2 peaks falls in a H2O trough and thus is highly effective. Whereas the methane peaks are somewhat covered by H2O.

Also the methane peaks seem rather sharp so does this mean that widening those peaks doesn't have much effect, whereas broadening CO2 peaks which are wider has larger effect?

So while some methane has some effect, adding more doesn't have much extra effect whereas for CO2 adding more does have more sizeable effect.

Perhaps all this is built into the GW potential numbers and doesn't affect the calculations you are doing.

I am not expert enough to know.

Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: August 01, 2018, 02:51:31 AM »

Actually, no, that's not true;;

Maximum warming occurs a median of 10.1 years after the CO2 emission event and has a median value of 2.2 mK GtC−1.

Seems to use lots of different models, so I doubt that is much of a problem.

I could easily be misunderstanding, but my impression is that the oceans take hundreds of years to warm up. So how is this study arriving at maximum warming after 10.1 years?

I am not sure, but suspect this study is putting 100GtC into atmosphere. Half of that gets absorbed by oceans fairly quickly; practically too quickly for heating effect to be noticed before it is gone but then land, weathering, other sinks and new ocean water coming to the surface take up more of the carbon over various timescales. So the carbon level reaches its peak very quickly and then declines.

So I believe there is lots more heating to come as the oceans warm up but in the study there is probably fairly steady declining CO2 levels as time goes on. The ocean warming is most rapid to start with but slows down over time. Consequently after 10.1 years the declining CO2 level becomes more important than the ocean heating so there is a slow net cooling.

If I am understanding correctly:

The pulse injection followed by declining CO2 levels in this study may be interesting, but that is not what has happened and if you want to know what happens if we stabilise GG levels, then there is decades if not hundreds of years of warming to come, at declining rates, assuming other things also stay constant.

Emissions for next 1 or 10 years have some effect but compared to effects of past 50+years all still working to warm the oceans, current emissions are small and don't have much effect for some time. Rework the numbers with 20 years of rapid emission changes and then you start to see noticeable effect.

I don't think the study is wrong, but you are being mislead by it.

Antarctica / Re: Rift in Larsen C
« on: July 09, 2018, 02:30:59 PM »
The 'monster' iceberg: What happened next?

Arctic sea ice / Re: How soon could we go ice free?
« on: June 16, 2018, 04:00:09 PM »
... If the models show a slowdown in the rate of decline as zero ice is approached and also the data is tending to show this recently...

Which models are you referring to? I've never seen a physics-based model with good predictive ability on this trend. True, there are models that don't work well, e.g. for the IPCC studies. If the model can't find the recent trend then it's not much use for predicting future trends.

Why do you say the data is showing a slowdown recently? If I look back at the linear fit of #97 then the residuals are all over the place and I don't see that trend. Based on the second plot, I suspect a quadratic fit would also curve downwards rather than upwards.

Lots of models. There are lots of graphs like attached below, some with many more model runs on them.

>" good predictive ability on this trend."

Clearly not they are all over the place on level of ice and also the trend. While some don't have enough data to see, all the model runs where you can see the change in trend where ice approaches zero is for the trend to get less steep as zero ice is approached.

Do we throw out all evidence because they are all over the place wrt level and trend? Or, do we say yes not much good for level or trend, but it looks like they all agree on trend in slope as zero ice is approached? So don't use them where they are bad but do use them for what they are good at, ie suggesting the change in trend as zero ice is approached declines.

>"Why do you say the data is showing a slowdown recently?"

The 4 parameter gompertz fit has a single inflection point. Whether I use Sept or April, that inflection point occurs in 2005. We have 12 years data since that inflection point. If there was only ~6 or fewer years data since the inflection point, I would be inclined to the opinion that 4 parameters might be too many parameters and I was overfitting. So just random residuals in last few years was allowing a better fit by using too many parameters. However with 12 years data past the infection point, that is too much data led and seems to me to be indicative that the data is showing a decline in the rate of decline.

See 4 parameter gompertz fit at top of this page.

>"If we're looking for a physical reason for a slowdown then I would point to the existence of a 'sanctuary region' against the North side of the CAA and Greenland where the ice hasn't melted out in any year."

Certainly wouldn't disagree with that being one physical reason, but I think there are lots of others.

I would tend to add in albedo feedback to this explanation (as well as deep water). In areas where ice moves out of the area, melting and ice movement allows albedo to drop and more sunlight energy be absorbed and this obviously helps additional melting. In contrast where ice piles up against Greenland & CAA, ice tend to move into area. So rather than melting and movement of ice causing extra area to open up, movement tend to close up areas opened by melting so it is much harder to get albedo drops to assist the melting.

If the ice retreats to a smaller area, that relevant area receives less sunlight energy so less volume melts seems quite possible. I guess this is complicated by winds bringing warmer temperature air so it isn't clear whether this accelerates or decelerates the volume of melt so maybe we need to look to the data and/or models?

Then there is oft discussed failure of MYI to make it around Beaufort gyre leading to rapid collapse of MYI to much lower proportion of the ice over a few years, but once we are down to these lower levels there is more FYI which almost completely recoveres itself each winter.

Are the people on these forums thinking through these reasonings and rejecting them because they don't believe they are significant compared to positive feedbacks they believe in? Or are they just rejecting the reasonings because it is just not exciting or they want to see catastrophic decline in sea ice or .... ?

Arctic sea ice / Re: How soon could we go ice free?
« on: June 16, 2018, 03:10:37 PM »
What observation? That the basic data clearly indicates a poof? That's not iffy. That must be the base assumption. In my opinion, the "iffy" assumption is to use a 2 dimensional, enthalpy ignoring mechanism to determine the first ice free Arctic. Any model that uses a "slab of ice" to analyse the past and make projections for the future is missing the big picture.

I'm not making any assumption, I'm only looking at the linear trends and that's what they show.

"I'm only looking at the linear trends" is just another way of saying 'if the linear trend continues' and that is an assumption you are making even if you want to try and say you are not making any assumption. FWIW I think you are making yourself sound ridiculous by clearly contradicting yourself.

As Ned W said

Yes, I agree with crandles.  Currently, some ways of extrapolating the past data show volume reaching zero before extent reaches zero.  There are three possible implications of that:

(1) Extent loss could speed up to match volume
(2) Volume loss could slow down to match extent
(3) Both extent and volume could change to reach zero at some other point

For some reason, a lot of people around here simply assume that (1) is the only possible outcome.  That's wrong. 

We both think the other is making big iffy assumptions. I think I have made the point and attempted clarification enough times, time to agree to disagree.

Arctic sea ice / Re: Arctic sea ice minimum early prediction
« on: May 30, 2018, 03:26:24 PM »
Like I asked above, and how I always vote.  Is there any good reason to vote anything other than the lowest?

Of course there is:

If too many people just go for the lowest and this turns out not to be the case, then this is setting up a 'those environmentalists are always crying wolf' defence for ff companies to continue not to act. Why hand them such a defence?

The forum / Re: Comments/posts can be liked now
« on: May 12, 2018, 02:24:58 PM »
Tried to like a post (link to do so visible) but now a pop up window says only people who have received 5 likes can like posts.

Policy and solutions / Re: Build, Baby, Build. In Fact, Overbuild.
« on: April 21, 2018, 10:55:51 PM »
I'll read the paper but 50% overbuilding is not enough.  Based on the data I've been able to use.

Wind and solar are dropping to $0.02/kWh.  Nuclear and storage are over $0.10/kWh.

We can greatly overbuild 2 cent generation before we start getting close to the cost of storage or nuclear.

2 cents * 1.5 (50% overbuilding) = 3 cents.

2 cents * 5 (500% overbuilding) = 10 cents.

I agree overbuilding makes sense. Less sure about 500% overbuilding 10 cents plus cost of maintaining distribution makes electricity expensive.

But even well before 100% overbuild, who gets paid what? Does the price come down to practically zero virtually all the time so there is no incentive to continue to overbuild? If those with contract for supply get paid but those without don't, why would anyone without contract for supply invest in something when rarely get any income?

Is there a possible market mechanism? Maybe some feature where solar PV and turbine owners are paid to switch off generation until point where indifferent between earning for supply of electricity and earning for turning off generation? Can this work to produce a reasonably efficient outcome? Can it be implemented if some currently have contracts for supply?

The forum / Re: Comments/posts can be liked now
« on: April 19, 2018, 12:32:43 PM »
Is there anyone who can see how many likes a particular post/comment receives?

Only for a brief period when it said who.

It would be nice to see which posts are liked. While I wonder if it tends to make the forum more of an echo chamber, it is worth trying it to see what happens.

The forum / Re: Comments/posts can be liked now
« on: April 18, 2018, 01:14:47 PM »
Have to hover over bar to see number of likes. Bar shows ratio of likes to posts.

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