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Climate Hustle

Global cooling - Is global warming still happening?

What the science says...

Select a level... Basic Intermediate

All the indicators show that global warming is still happening.

Climate Myth...

It's cooling
"In fact global warming has stopped and a cooling is beginning. No climate model has predicted a cooling of the Earth – quite the contrary. And this means that the projections of future climate are unreliable." (source: Henrik Svensmark)

When looking for evidence of global warming, there are many different indicators that we should look for. Whilst it's natural to start with air temperatures, a more thorough examination should be as inclusive as possible; snow cover, ice melt, air temperatures over land and sea, even the sea temperatures themselves. The key indicators of global warming shown below are all moving in the direction expected of a warming globe.

Indicators of a warming world based on surface, satellite, and ocean temperature measurements, satellite measurements of energy imbalance (the difference between incoming and outgoing energy at the top of the atmosphere), and of receding glaciers, sea ice, and ice sheets, rising sea level, and shifting seasons.

The question of global warming stopping is often raised in the light of a recent weather event - a big snowfall or drought breaking rain. Global warming is entirely compatible with these events; after all they are just weather. For climate change, it is the long term trends that are important; measured over decades or more, and those long term trends show that the globe is still, unfortunately, warming.

Basic rebuttal written by LarryM

Update July 2015:

Here is the relevant lecture-video from Denial101x - Making Sense of Climate Science Denial

Last updated on 5 July 2015 by skeptickev. View Archives

Printable Version  |  Offline PDF Version  |  Link to this page

Related Arguments

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On 21 January 2012, 'the skeptic argument' was revised to correct a minor formatting error.


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Comments 201 to 250 out of 305:


    scliu94 wrote: "What do you guys make of this?"

    I can make...

  2. scliu94 - Fun word for the day: the proper term for that particular article, and its author, is mumpsimus. "A view stubbornly held in spite of clear evidence that it's wrong; a person who holds such a view."

  3. It seems to me that sea level gives the clearest evidence of continued heating of the earth’s surface. It is possible to estimate the rate of increase of ocean heat content from the rate of rise in sea level. My estimate below is about double the rate determined from ocean temperature measurements in the top two kilometers of the oceans. I haven’t seen a similar computation elsewhere. If someone else has done this before, please let me know.

    The largest contributors to changes in global sea level are heating of the oceans and decrease of Greenland glaciers and Antarctic glaciers and ice shelves. Storage of liquid water on land decreases sea level and extraction of groundwater increases sea level. Storage can have significant short-term effects; but the long term combination of storage and groundwater extraction is modest (See IPCC WG1 Report Chapter 3 p. 318, 2007). Gravity measurements tell us the contribution from Greenland and Antarctic ice. Once we correct the rate of rise of sea level for polar ice, we can compute the rate of ocean heating required to cause the thermal increase in sea level.

    The complication is that ocean heating varies with location and depth and that the thermal expansion coefficient varies with seawater temperature and pressure. See this for the computation of seawater thermal properties. The variation of thermal expansion is greatest for temperatures above 15 Centigrade and very little seawater exceeds 15 C for depths greater than 100 meters. Thermal expansion is small below 10 Centigrade at low pressures, but it increases with either increasing pressure or temperature. We can set an upper limit for thermal expansion at a particular temperature by using the high-pressure value. Nearly all the volume of the Atlantic Ocean is 15 C or colder. With these considerations, we can select the high-pressure thermal expansion coefficient for 12 C as an upper limit to a representative value for the entire ocean. That value is 0.00022 / Centigrade. For comparison, the effective coefficient in Schuckmann 2009 (pre-publication copy) is 0.00017.

    Here are details of the computation:

    The net rate of sea level rise is

    Rn = Rt – G / (So * Dw) = 3.2 mm/yr – 213 Gtonne/yr /(

    Rt = 3.2 mm/yr over the last 20 years

    G = 213 Gtonne/yr over the last 20 years Shepherd et al. (2012)

    So = ocean surface area = 3.6 E+14 m^2

    Dw = mean density of fresh water = 1000 kg/m^3

    Rn = 2.6 mm/yr

    dV = rate of increase of seawater volume = Rn * So

    dV/V = a * dT

    V = total seawater volume

    a = effective thermal expansion coefficient for seawater = 0.00022/C

    dT = mean rate of increase of seawater temperature

    dT = dE/(V * Ds *Cp)

    dE = rate of increase of ocean heat content

    Ds = mean density of seawater = 1030 kg/m^3

    Cp = mean heat capacity of seawater = 4000 Joules/kg/C

    Combining the last two equations, we can eliminate the ocean volume and obtain

    dE = Ds * C * dV / a = Ds * C * Rn * So / a = 1.76 E+22 J/yr = 5.6 E+14 Watts

    The heating rate averaged over the ocean surface area is dE / So = 1.55 W/m^2, twice what Schuckmann gets from temperature measurements. Averaged over the earth’s entire surface the rate is 1.09 W/m^2, which is consistent with the IPCC estimate of net radiative forcing (Climate Change 2007: Synthesis Report, p. 39).

    The greatest uncertainty in this computation is in the effective thermal expansion coefficient. If anything, the value I've used is too large. A smaller value would result in a larger computed rate of heating.

  4. Another one from the guy:


    "I agree that D-O events may not be global events. On the other hand, if you look at the temperature profiles I posted in the forums previously, you see that the equater is cooling, as is the antarctic.

    Since we are predominantly seeing global warming in the arctic and northern temperate zones, how do you know the data isn't a more regional warming event - as opposed to global warming."


    I was wondering if evidence could be supplied to help me prove this guy wrong? 

  5. Another one from the peanut gallery. 

    "if you look at the temperature profiles I posted in the forums previously, you see that the equater is cooling, as is the antarctic.

    Since we are predominantly seeing global warming in the arctic and northern temperate zones, how do you know the data isn't a more regional warming event - as opposed to global warming.”

  6. tkman0 - It's global. Here's a video demonstrating that. And here's Marcott et al 2013, who show that recent climate changes are unprecedented in the Holocene despite any possible Bond events. 

    I would suggest giving him a link to the Most Used Myths, and having him tell you what doesn't answer his questions and hypotheses. If he has to keep changing his argument he didn't have a solid one to start with. 

  7. tkman0 - Where is this discussion occurring?

  8. tkman0 @204, looks pretty global to me:

    The graphs of the trend in warming from 1880-2013.  The upper graph shows the data by zone, while the lower shows the average for each latitude band.  As you can see, the equator shows a trend of around 0.8 C over that period, or 0.06 C per decade.  The band with lowest warming is at 60 degres South (0.02 C per decade).  That is low relative to the average (0.07 C per decade) but it is still warming - not cooling.

    I suspect your interlocuter's data only shows ocean temperature anomalies relative to some recent period, where the recent La Nina's have draged the equatorial trend down.  They are, however, short term fluctuations, and if that is what they have done, they are cherry picking.

    The data comes from the GISS website, and is very usefull for debunking denier claims.  You absolutely should bookmark it if you are interested in the debate. 

  9. tkman0, there are a variety of tools available to look at such things.  Here's GIS Land-Ocean Temperature Index (GIS L-OTI) for the last decade, and here's the main page for the tool.

    Here's graphed data for three latitudinal bands.

  10. @KR, they're private messages back and forth between us because we were causing a rucus on the forums. As to the probably dont wana know, not really your typical website for every day use.  

  11. Out of interest, the difference between the video linked to by KR and the data in the graph I showed above is that the data above is pure thermometer based data.  Because there were no meteorological stations in Antarctica in 1880 (and indeed, not till the 1950s), it is unable to show temperatures for that period and hence no trend from that period either.  In contrast, KR's video appears to be a reanalysis product.  With reanalysis, they feed actual observations into a climate computer so that the computer's output is constrained to match observations where they are available.  They then allow the computer to fill in the missing data.  The process is accurate to a fairly high standard, but not perfect (nothing in science is).  I would trust it as as good a representation of the actual temperature trends in those areas we are likely to get.  You should, however, be aware of the difference so you can answer sensible questions (how did they measure Antarctic temperatures in 1880) and stupid ones ("I did not know we had satellites in orbit in 1884").  For the last, check the Youtube comments, or alternatively keep a hold of your braincells, and don't. 

  12. tkman0: Suggest that you invite your friend to post his/her concerns here on SkS.  there really is no need for you to play the role of middleman.  


    [TD] But please inform your "friend" to keep each of his/her comments narrowly on one topic, to post each comment on an appropriately narrow thread, and to read the original post to which that thread is attached before writing the comment.  I strongly suggest your friend not write any comments until after reading The Big Picture followed by The New Abridged Skeptical Science Reference Guide.

  13. Global cooling - Is global warming still happening?

    My first post: Antarctic ice is above 1981-2010 mean. March 20, 2014 Arctic ice is 3-5% below that same mean. There have been 3 consecutive recovery winters at the Arctic.Arctic sea ice area is 800,000 sq. km. below mean amount of >15% sea ice coverage. This is a lot, but this past winter added 800 cubic miles (3200 GTonnes) to the Arctic ice mass, to reach a peak of 2200 cubic miles of sea ice. This has to poke a hole in the "Polar Vortex" story. With normal ice volume, near normal ice area, how could it be so warm that the polar vortex was caused. This polar vortex narrative is getting harder to justify as each day goes by.


    [JH] Pelease cite the sources for your data and for your assertions.

    BTW, your subesequent comment was pure unadulterated, off-topic, concern trolling. It therefore was deleted. 

  14. Jetfuel @213 writes, "There have been 3 consecutive recovery winters at the Arctic."  Those would have to be the winters of (in reverse order) 2013/14, 2012/13, and 2011/12.  It is amazing how the summer record low Arctic sea ice extent in 2012, with a minimum sea ice extent nearly half (55%) of the 1981-2010 mean, and around 1/5th lower than the prior record in 2007 (82%).  That the winter of 2011/12 could be a "recovery winter" clearly shows that what ever that undefined term means, it is irrelevant to Arctic sea ice analysis.

    Even worse, the Arctic sea ice extent as of May 5th was 13.07 million km^2, only 0.657 million km^2 (4.8%) less than the 1982-2010 record, but still the third lowest on record - and lower than any year since 2007.  So not only are "recovery winters" no indication of summer sea ice extent, they are no indication of spring sea ice extent either.

    Jet Fuel, in other words, is feeding us irrelevant (and dated) data, not to mention completely failing to indicate how the facts he adduces are relevant to either the OP, or the claims he makes about polar vortexes. 

  15. Just to add to Tom's comment on the three recovery winters, thisimage from the NSIDC puts those winters into context very nicely:

    The annual maximum sea ice extent usually takes place in March each year, and as you can see the last three winters have basically followed the long term declining trend in March sea ice.

    My recommendation to jetfuel is to look at the long term trends because measurements for individual years or a few years are too susceptible to cherry picking.  As Tom says, the winter sea ice extent maximum is not a good predictor of the summer minimum, as it depends a lot on Arctic weather during the summer (which causes a lot of variability around the long term trend).  Also we should expect a larger *increase* in sea ice following a decreasing summer minima, simply because it leaves more open water to freeze (which gives a good opportunity for a misleading report of the "recovery", indeed SkS rebutted such arguments made by WUWT and Steve Goddard last year).

  16. Yesterday PIOMAS came out with Arctic Sea Ice Volume measurements (h/t Neven).  Their site says:

    "The 2014 ice volume reached its annual maximum in April with 22,900 km3 which is just slightly below the long term trend and is the second lowest on record; just 400 km3 above the previous April minimum which occurred in 2011. However, variations over the last 4-years are well within the error bars of the volume estimates so that inter-annual variability over this period maybe due to errors in the sea ice reanalysis."

    This is the second lowest annual maximum on record.  Within the error measurements it is equal to the record low.  Where did Jetfuel come up with a recovery???

    Another set up for an interesting summer in the Arctic.

  17. jetfuel wrote: "This has to poke a hole in the "Polar Vortex" story"

    Umm... why exactly? Even if we pretended that Arctic sea ice really was 'recovering'... how would that call in to question the long term common Arctic air flow pattern?

  18. nsidc data shows late March peaks of 15.22 million sq km for 2012, 15.1 million for 2013 and 14.9 million for 2014. The 1981 to 2010 avg is 15.4. The avg of 2012-2014 March peaks is 2.13% below the 1981-2010 avg peak of 15.4 million. 2.13% less ice area is the reason the Polar Vortex fell apart? The other 14.9 million sq km of ice couldn't save the vortex? Then, why hasn't this Vortex disintegration happened nearly every other year? Area with at least 15% ice is a rough indicator. the tremendous increase in ice volume in 2013 and 2014 also needs consideration. 2014 saw an 800 cubic mile seasonal increase in sea ice volume. That's the source of the 'recovery' I spoke of. For me to believe the 'polar vortexfell apart' line, I'd expect 10% less ice volume compared to last year, not 1.3% less ice area (14.9M vs 15.1M sq km) and a volume increase.


    [JH] What is the basis of your "10% less ice voume" metric? Is it merely your personal opinion, or is it based on sound scientific research?

    In case you have not noticed, personal opnions about science carry very little weight with the users of this website.  

  19. jetfuel:

    Do you think that Arctic maximum extent is the only factor determining the behaviour of the polar vortex? Yes or no?

    If yes, can you justify this position?

    As far as your comment on the ice volume goes, PIOMAS anomaly data show ice volume has dropped by approximately 10,000 km³ since 1979. An 800 km³ increase in one year (and there are plenty of upward jolts in the data even as it follows the downwards trend) is much too short a time period to start speaking of a "recovery".

    I have reproduced the graph below:

    Arctic sea ice volume

  20. jetfuel:

    Please note that posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.

    Please take the time to review the policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.

  21. jetfuel, I demonstrated that the "recovery" was actually just a continuation of the downward trend in March maximum sea ice extent, and that an increase in the winter gain is what is expected simply because March sea ice extent is declining a bit more slowly than the September minimum extent.

    There is nothing special about the recovery in the last three years.  If you disregard the evidence and cherry pick in this manner, don't be surprised if your assertions are viewed with skepticism.

  22. jetfuel's numbers for ASIV make no sense whatever unless it is about the state of the Arctic back in early November 2013 & the numbers are not meant to be exact.

    @218 jetfuel states "This is a lot, but this past winter added 800 cubic miles (3200 GTonnes) to the Arctic ice mass, to reach a peak of 2200 cubic miles of sea ice." Since the summer 2013 minimum, PIOMAS has never shown numbers higher than 2,620 cu km (ie GTonnes) above the previous year. That was back at the beginning of November 2013, more Autumn than Winter. That difference has been shrinking since then & since the beginnng of March 2014, ASIV has been lower than the 2013 equivalent. This '2200 cubic miles' figure is ~9,000 cu km. That was the value of ASIV back at the beginning of November 2013.

    As for the relevance of these numbers - pass.

  23. JH, from your response to my 10% number. I'm trying to find support for the polar vortex line I've been told. Does the scientific expert concensus say 2% or more under March 2013 mean total ice area easily triggered this winter's polar vortex disintegration? I'm looking for an anomoly where it is much warmer in the Arctic in the winter so as to cause a once in decades event. I'm not seeing such an anomoly is total late March 2014 sea ice. Not seeing it in Antarctic sea ice coverage over last 2 years. Not seeing it in 2014 ice volume at the Arctic (up 800 cubic miles). What I do see is a dramatic improvement from 2012 to 2013 Sept Arctic sea ice area, revovering 49% of the gap to 1981-2010 mean sea ice coverage (nsidc). From the 3.45M sq km of sea ice on Sept 13, 2012 to 5.1M sq km on same day of 2013 is a 49% recovery of the 3.37M sq km gap from the 3.45 of 2012 to the 1981-2010 mean of 6.82 M sq km. Why just focus on the .8M sq km or so gap in max ice area (~2-3%) in March and ignore the 11+M sq km seasonal 2013 increase? In questioning my use of 'recovery'? 11+M is a whole lot more new added ice for it to be coinciding with the Polar Vortex falling apart. On the contrary, with 11+M sq km of new ice added, it makes sense to me that this winter was like it was. It was ranked 53rd coldest in Indiana in the last 100 years. Pretty average for the last 100 years. 2nd consecutive winter wher it is colder than the previous one. If the '14-'15 winter makes another similar jump, we might break the 1979 Great Lakes frozen area % record that we came within 1% of this past winter.

  24. jetfuel.

    It is probably too simplistic to try and relate the splitting of the polar vortex to just ice extent. There were major influxes of warm air into the Arctic along 2 corridors - the east pacific and US West coast, and east of Greenland over Svalbard. These incursions of warm air split the vortex and in effect partly pushed it out of the Arctic. Given the time of year this occurred at I think it was more likely directly caused by weather patterns further south. However that doesn't rule in or out other relationships between the polar regions and lower latitudes. For example changes in NH snow cover, changes to the Polar Jet Stream, warming of ocean currents affecting Sea Surface Temperatures etc. Things are changing up there, global warming is a very big part of that, but the exact dynamics and trajectory of everything that will happen isn't clear. One thing that is pretty clear is that the cause-and-effect chain for any changes won't have just two links in it.

  25. From nsidc: Preliminary measurements from CryoSat show that the volume of Arctic sea ice in autumn 2013 was about 50% higher than in the autumn of 2012. In October 2013, CryoSat measured approximately 9,000 cubic kilometers (approximately 2,200 cubic miles) of sea ice compared to 6,000 cubic kilometers (approximately 1,400 cubic miles) in October 2012. About 90% of the increase in volume between the two years is due to the retention of thick, multiyear ice around Northern Greenland and the Canadian Archipelago.

    This didn't have anything at all to do with this last very cold winter?

  26. jetfuel @223 writes:

    "I'm looking for an anomoly where it is much warmer in the Arctic in the winter so as to cause a once in decades event"

    Let's ignore the fact that the cold North American winter was not a once in decades event, but an almost commonplace winter as little has half a century ago; and has only become exceptional by comparison to recent warmth.

    Rather, let's focus instead on the unusual situation where jetfuel claims to be looking for anomalous warmth, but does not bother looking at surface temperatures to find that anomalous warmth:

    (Gisstemp polar authographic projection of 2014 winter temperature anomaly.)

    We'll also not ignore the fact that the theory jetfuel is criticizing is that reduced sea ice extent in late autumn creates greater warmth in the Arctic, destabilizing the jet stream resulting in unusually cold early winters.  Therefore references to March sea ice extents, sea ice volume and (most especially) Antarctica are all red herrings.  What he should be looking at is the November sea ice extent which was the sixth lowest on record.  That was only 6.8% below the 1981-2010 average, but that period (1981-2010) shows continuous decline so that it was much more than that below the 20th century average.

  27. jetfuel @225.

    You appear to be asking a rhetorical question - "This didn't have anything at all to do with this last very cold winter?" What is still a mystery to me is which winter you are trying to refer to. 'This last winter' was not 'very cold' for an Arctic winter. Indeed, it was rather warm. (See this graphic of Arctic Ocean Lower Troposhpere Temperatures - usually 2 clicks to 'download your attachment'.) Nor was the previous winter (2012/13) particularly cold. What was cold was the Arctic summer & autumn of 2013.

    Given such circumstance, the use of your rhetorical question appears to be misplaced. Indeed, you point out yourself that extra ice volume is due in part to the "retention of thick, multiyear ice", a situation more associated with low levels of melting than with high levels of freezing which sort of fits with the Arctic temperatures over recent seasons.

    So is your use of the term "winter" correct and if so which winter are you attempting to refer to?

  28. 2011-2012 winter was hardly a winter. 2012-2013 was normal for winter. 2013-2014 was setting all kinds of records in Indiana. We just broke a record for fewest 70 degree days by late April that stood for 99 years.

    Warm air always blows up into the Arctic. whether it stayed there or not this past winter, it formed over 11 million sq km of new ice between Sept 2013 and March 2014, and while that was happening, the Arctic is so unusually warm, that it splits up it's cold air mass and smaller pockets drift down over Canada, Indiana, etc. So this year the bad news is: it's negative 25 instead of negative 35 at the North Pole while a new record is set for newly formed seasonal ice area increase throughout the Arctic?

    "One thing that is pretty clear is that the cause-and-effect chain for any changes won't have just two links in it" This is exactly why the Polar Vortex narrative that followed 2 days of media silence on Jan 24th this year, used to explain why we were having a normal 1900's winter, and so universally pushed on me by the media, has me agreeing with this quote and all this PV narrative. If the north pole fell apart in January, then as winters and summers have gotten colder where I live over the last 30 months, it seems that just the opposite is happening. Something about warmest Arctic air causes nearly most ever, if not most ever, ice to form during the same time doesn't sound right. And now I'm told that the PV breakup is common pattern? This was the most uncommon winter since 1993-4 here. What recent year exhibited this same PV disruption?


    [JH] Please specify the geographic that is covered in your characterization of recent winters. Is it North America? The entire Northern hemisphere?  

    You also state: This was the most uncommon winter since 1993-4 here. Where is "here"?

  29. jetfuel @228.

    You say " formed over 11 million sq km of new ice between Sept 2013 and March 2014." I do not recognise that figure. Using NSIDC monthly data, Arctic SIE rose 9.45M sq km. Daily SIE data from JAXA increases this slightly to 9.64M. Daily SIA yields a yet larger number - 9.92M - but none of these nmbers are "over 11 million sq km" and none of them are "a new record."

    I am therefore entirely perplexed as to what it is you think you are about with these numbers you present here. Explain yourself - if you can.

  30. jetfuel, frankly speaking your sense of personal incredulity about what is going on is not a sufficient substitute for analysis based on the available evidence. Especially not when you are backing that up with sea ice numbers that appear to be coming out of thin air.

    I should like to reiterate Tom Curtis' point that winters that are exceptional in the 1990s through the present were once a commonplace, and as such by over-stating their importance you are falling for the shifting baselines fallacy.

    I must make a special note about:

    used to explain why we were having a normal 1900's winter,

    Well, yes. Because in the 2010's a "normal 1900's winter" is exceptional and requires an explanation.

  31. Also, this year's sea ice maximum extent was the fifth lowest in the satellite record. What is more, the seven lowest maximum extents have all occured in the last seven years.

    And, now that I've noticed it:

    then as winters and summers have gotten colder where I live over the last 30 months,

    First, citation please. Second, what of it? A small region on the Earth is very likely to see much more variability in its temperature trends in 30 months than it will in, say, 30 years (which is the usual standard for establishing temperature trends in climate).

  32. jetfuel @228, it is not part of the polar vortex theory that the large southern excursions of the polar jet stream that brings unusual cold for the 21st century will always occur over Illinois.  On the contrary, it is a chaotic process, and can at any longitude.  Thus, in 2011 it occured over Europe, and weakly over the US eastern seaboard:

    In 2012 over the extreme eastern region of Siberia:


    In 2013, over the Siberia, Mongolia, China and Japan:

    And as already seen, in 2014 it occured over the majority of the contiguous US.

    Further, the theory is not that similar events have not occured in the past.  Rather, it is that the warmer Arctic ocean makes such events far more likely.

    If you are going to criticize a theory, you need to actually read the theory in the scientific papers, and make sure you understand it.  If not, you will inevitably end up criticizing a straw man.  You can start with Honda et al (2009), which discusses the connection specifically with connection to Eurasia, and Liu et al (2012) , which extends the theory to include the US.

  33. Geographic area: Central Indiana, Yes, sorry, I did have the last two winters switched for ice area growth. The second to last season was the one with over 11M of increase.

    All from nsidc: In Sept 2012: 3.425M sq km ice area. In Mar 2013 peak day: 15.10M sq km. 15.1-3.425=11.675M sq km increase. I will eventually learn how that compares since 1981. Then after that huge increase, the following winter saw only 15.229-5.1=10.129M sq km. Sorry I had the two years confused with each other. Still, one would think that both years are normal or above normal ice increase (10.129 and 11.675 million sq km). For instance, Sept 23, 1997 to March 1998 increase was only 9.328M sq km of increase, and that was one of the the coldest recent winters, peaking at 15.955M sq km of ice area.

    Warmest Arctic air in a while causes nearly the most ever (10.1M), if not most ever (possibly the previous year with 11.675M), sq km of ice to form during the same time puzzles me as to why the warm air didn't stunt ice growth comparatively.

    Records, records, and more records: from clarifies my earlier estimates:

    "Lake Superior is still over 60 percent covered in ice as of yesterday Saturday April 26, 2014. The satellite pictures shown above were the latest I could find that had clear skies and good vision of the ice. These high resolution satellite images come from April 23 and April 24, 2014.

    On Wednesday April 23, 2014 Lake Superior had 68 percent ice cover. According to the Great Lakes Environmental Research Laboratory, the previous highest amount of ice on that date was in 1979 when there was 38 percent ice cover.

    So the ice on Lake Superior is currently almost twice as much as recorded for this late date in the ice season. The records go back to 1973.

    On Wednesday, Lake Michigan still had 15 percent ice cover. The highest amount in the records on that date was five percent in 1979. This means Lake Michigan has three times the previous highest ice amount on April 23.

    Lake Huron was still reporting 25 percent ice, with the previous late season high at 11 percent in 1996."

    I learned that while area never eclipsed the 1979 mark, the lasting of ice was the highest on record. This tells me that possibly the volume of ice was surely a record since accurate records of area started in 1973. Some said 2014 was going to be the summer of zero Arctic ice. It may turn out to be the summer of June Lake Superior ice. In other news media statements, I'm led to believe that I live in the only part of Earth that is cooling over last 30 months. US Midwest.


    [JH] Posting a potpurri of factoids is akin to sloganeering which is prohibitied by the SkS Comments Policy. Future posts of this nature will be summarily deleted.

    Since you have repeatedly posted poturris of factoids, you are also engaging in excessive repititon which is also prhobitied by the SkS Comments Policy.

    You are now skating on very this ice indeed. 

  34. jetfuel wrote "All from nsidc: In Sept 2012: 3.425M sq km ice area. In Mar 2013 peak day: 15.10M sq km. 15.1-3.425=11.675M sq km increase. I will eventually learn how that compares since 1981. "

    perhaps you should perform this analysis before making claims about how unusual the increase is.  Now had you been paying attention to the replies to your comments, you would know that the answer has already been pointed out to you more than once.  Here is the important graph:

    The increase isn't that dramatic compared to previous years, and is due to the fact that winter maximum is declining a bit more slowly than the summer minimum (for fairly obvious reasons).  However the trends in both are downwards.  Look at the trends, not the noise.

  35. DM @234, the graph you show shows almost no trend for sea ice extent maximum.  It also shows sea ice extent maximums substantially less than the March average sea ice extents from the NSIDC:

    As the link to the image you use mentions Goddard, how sure are you of its reliability?

    In any event, here is the EEA arctic SIE analysis for Nov 2012 (there most recent), which has the advantage of showing the trend lines:

    As can be seen, the trend for both March and September are both negative, but the absolute value of the September trend is more than twice that of March.  It follows, as you point out, that the sea ice extent recovery increases, on average every year.

    It is very clever of jetfuel to turn evidence of decreasing sea ice extent at all times of year into proof that the Arctic is cooling /sarc

  36. Dikran, I looked at the NH min sea ice trend you predict. It looks like a good fit, but 2013 (not incl) bounced back to the very upper limit of grey shaded area (@5.1M) and 2014 will have to be less than 5.1M min for the 95% CI to continue to match. Your graph ends with 2012. The 2012-2013 recovery reasonably matches the largest of any shown, that of 1997-8. Looks like 2032 is the min=0 prediction without 2013 data included. I presume this chart will be redone if Sept 2014 min exceeds 5.1M?

  37. jetfuel @236, here are the relevant figures taken from the NISDC, and converting the percentage trends given by the NISDC to trends in area for ease of comparison:

    March 1981-2010 mean Sea Ice Extent (SIE): 15.53 million km^2

    March SIE trend: -0.404 million km^2/decade

    September 1981-2010 mean SIE: 6.52 million km^2

    September SIE trend: -0.893 million km^2/decade

    1981-2010 mean SIE recovery: 9.01 million km^2

    SIE recovery trend: +0.489 million km^2/decade

    From this it is easy to sea that we expect the 2013-2014 to be one of the largest known based on comparative trends alone.  We expect 2012-2013 to be the largest, or very close to the largest known, because the September 2012 sea ice extent was the lowest ever known and March sea ice extents do not decline as fast as September sea ice exents.

    You are, to put it bluntly, trying to convert evidence that both summer and winter sea ice extents are declining, but the winter sea ice extent is declining slower into evidence that the sea ice extent is recovering (ie, growing larger).  You now have all the relevant facts before you in a very clear fashion.  Persistence in your obsession on this point will merely prove you to be an utter fool, or dishonest.  Consequently if you fail to respond acknowledging this point, I will strongly recommend to the moderators that you be barred from SkS on the grounds of persistent sloganeering.

  38. TC, in #235, The trendline looks OK. .0447M km2 per year shown as straightline decline of maximums and so an 11.675 M increase in one seasonal swing 2012-13 is 261 times the .0447M/yr decreasing trend. I added in sept 2013 and sept 2014 since they are now on the books and could draw a last 11 year trend line with a positive slope for maximums.

    How I get 11.675M for sept 2012 to Mar 2013: Was this ever exceeded before?


  39. I added in sept 2013 and sept 2014

    ... wait, what?

  40. Jetfuel

    "Was this ever exceeded before?"

    No...and by saying that you are essentially agreeing with the point that  Tom and DK are making.  Let's make sure this is clear.  Summer sea ice minima and winter sea maxima in the Arctic are both declining. Because the decline in summer ice minuma has been faster than the decline in winter sea ice maxima, a record low summer minimum is very likely to show a record seasonal increase in sea ice extent. Rather than suggesting that sea ice is recovering, the large seasonal increase means that more and more of the ice at the start of spring melting season tends to be thinner first year ice, which tends to melt more readily the following summer, contributing to larger seasonal variation.  

    "...a last 11 year trend line with a positive slope for maximums."

    Why 11 years?  Why not 20?  Or maybe the whole length of the data set?  Can you show that the trend of the last 11 years is statistically different than the entire record?Before you try, I'd point out that the 2014 arctic sea ice maximum in the NSIDC graph presented by Tom falls almost exactly on the long term trend line.  

  41. jetfuel

    I'd like to add that in all your interactions so far, you've tried to find ways to make the data say what you appear to want it to say, rather than engaging in an honest give and take about what the data actually says. This is a one way street at present, with commenters here providing helpful context, and you, so far, largely ignoring them to push your predeteremined interpretation.

    Look, no one (and I really mean nobody) I know is happy about what these data imply, but the tale they tell is very straightforward. Arctic sea ice is melting, as we would expect giving warming sea and air temperatures. It's just not that complicated. If you have to do intellectual summersaults to say otherwise, that is a giveaway that you are arguing a losing case.

    BTW...I meant DM in the previous post...not DK.

  42. jetfuel, another thing to keep in mind is that the Arctic is largely land-bound.  Sea ice growth is limited by land.  Summer ice is free to drop according to climate (troposphere/surface/ocean) conditions.  Winter ice is free to grow southward only up to a certain point. If winter growth were unfettered, the winter max would be much larger, especially earlier in the record, and the negative trend would be much steeper.   

  43. Another way to think about this - imagine what happens when the artic is ice-free in summer. The "recovery" in winter is even larger - because the oceans will have to warm a great deal before a sunless sea will not develop a layer of thin ice on top. But this is not "recovery". Recovery is when there is more ice at a particular time of the year than at the same time in other years.

  44. Jetfuel wrote "Dikran, I looked at the NH min sea ice trend you predict.It looks like a good fit, but 2013 (not incl) bounced back to the very upper limit of grey shaded area (@5.1M) and 2014 will have to be less than 5.1M min for the 95% CI to continue to match."

    That was not the result to which I directed your attention, as I suspect you are fully aware.  I was directing your attention to the fact that sea ice extent is decreasing more slowly in March than it is in September, which explains why we expect the annual increase to be increasing.  The reason I showed the graph that I did in my previous message was you make sure you knew what part of the post was relevant.  In disregarding this, you have given a strong impression that you are not interested in the truth and are just trolling.

    "Your graph ends with 2012. The 2012-2013 recovery reasonably matches the largest of any shown, that of 1997-8. Looks like 2032 is the min=0 prediction without 2013 data included. I presume this chart will be redone if Sept 2014 min exceeds 5.1M?"

    Again you are just avoiding acknowledging that an increasing recovery is exactly what we would expect, i.e. you are trolling. 

    See Toms' excellent post for a further illustration of this.

    Do you accept that we should expect an increasing trend in the recovery from the September minimum to the March maximum.  Please give a straight answer, yes or no.

  45. I thinkthis graph well illustrates the point that all this blather about "record freeze" is away with the fairies.

    The black line is the increase in Arctic SIE from minimum to maximum. The blue line is the March SIE displaced for reasons of comparison. It is very evident this maximum has no significant bearing on the black trace. And it is evident from the red trace that the minimum, the outcome of the previous melt season, has everything to do with it.

    I hope I didn't make it more complicated than kerosene.

    Arctic SIE freeze up.

  46. All: A friendly reminder — Dogpilling is prohibited by the SkS Comments Policy.

  47. All: Please do not immediately respond to jetfuel's next post. I would like to review it and determine whether or not it constitutes sloganeering and/or excessive repetition. If it does, the comment will be deleted.

  48. I will respond to jetfuel's most recent post tomorrow, after JH has had a chance to review it, as requested.


    [JH] Thank you.

    jetfuel's most recent post violated three SkS comment restrictions, i.e., no sloganeering, no excessive repetition, and no moderation complaints. His comment was therefore zapped. 

  49. US natural gas supplies are at an 11 year low. Jeffrey Folks article on American Thinker: "A recent report on natural gas usage during this past winter. For the first time, the U.S. burned more than 3 trillion cubic feet of natural gas this winter, most of it for heating. That was more than the 2.3 trillion cf of 2012-13, and double that of 2011-12.

    That evidence is irrefutable. We have lived through a winter of historic proportions – the coldest winter in Vermont’s long history, and the third-coldest for the city of Chicago. Gas futures also provide evidence about next winter.

    Futures traders are highly sophisticated investors who base their trading on all known information.  Futures traders care only about the facts. When they are right about the facts, they stand to make a great deal of money."

    I took a survey on CO2 and found out a few things: I generate 4.6 tons of it per year. Unfortunately, the site told me my result was above the world average of 4.0 tons, and that we 6.6 Billion Earth inhabitants need to all cut back to an average of 2 tons each to stabilize current global CO2 levels. For me to get down to 2 tons, I need to bump my 32 mpg sedan up to 70 mpg without any factory participation and turn my house from 66 degrees down to about 50 degrees all through next winter, and set my a/c on 85 this summer. Then, if 6.6 Billion others each also cut their use in half, Moana Lau can hold steady at 401 ppm CO2.

    Not going to happen, but the US is reducing CO2 production by 7% per year and we make about 7% of the human made CO2 in the world. I wonder how our 3 trillion cu ft of nat gas use compares to our gasoline use.


    [JH] Stop wondering and start researching. Google can be  your best friend.

  50. @jetfuel It may have been a harsh winter in Vermont, however it was an unusually mild one in the U.K.  However the plural of anecdote is not data.  If you want to make an argument that it is cooling, fine, but present the data supporting your argument, not just cherry picked press stories.

    As to Arctic sea ice extent.  There are a variety of reasons that the annual "recovery" is increasing.  The most obvious is that it is dark during much of the winter in the high Arctic and any open water is likely to freeze up.  The smaller the September minimum, the more open water there is, the more first year ice will form.  This isn't rocket science.  As to why the March maximum is declining more slowly than the September minimum, I'd say it was a combination of at least two factors.  Firstly it is dark in the high Arctic during much of the winter, so the "regional" greenhouse effect is relatively small as the Sun is not warming the surface.  Secondly, when the ice pack is relatively solid during the winter, it will be less affected by Arctic weather, principally wind which pushes the ice about more in the summer when it is broken up, rather than more or less contiguous during the winter. 


    [JH] Excellent advice. Unfortunately, jetfuel is unlikley to take it because he has been ignoring such advice since he began posting comments on SkS. I suggest that everyone completely ignore what jetfuel posts from here on out. I have recommended that jetfuel's comment privileges be rescinded.    

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