@dabize: please stamp on the idea that nuclear winter will save us, very firmly. The chilling effects of nuclear winter, according to Hansen (I think), as well as those of a massive above-ground volcanic eruption, will last for about seven years, on average. After that, we will be right back where we would have been had no nuclear explosion occurred. And, right now, the "overkill" in nuclear winter will create massive problems of starvation on its own.

I'm sorry, it may be off-topic but I can't resist posting this Flanders & Swann ditty on English weather: January brings the snow; Makes your feet and fingers glow! February's ice and sleet - Freeze the toes right off your feet! Welcome March with wintry whine ... Would thou wert not so unkind :( April brings the sweet spring showers ... On and on for hours and hours! Farmers fear unkindly May: Frost by night and hail by day. June just rains and never stops! Thirty days and spoils the crops. In July the sun is hot! Is it shining? ... No, it's not! :( August, cold and dank and wet Brings more rain than any yet. Bleak September's mist and mud Is enough to chill the blood! Then October adds a gale! Wind, and slush, and rain, and hail ... Dark November's chill and fog - Should not do it to a dog! Freezing wet December then ... Bloody January again!!!! (January brings the snow, etc.)

@Neven: if volume is "per abnormal" but average thickness is down at this time of year, that probably means additional ice at lower latitudes, which will melt out early anyway, plus less thickness than usual further north. I'm afraid I'm not reassured by this at all ...

Hi all - I have just done a blog post on a peripherally-related topic (runaway greenhouse gas effect) at waynekernochanblog.blogspot.com. I would very much welcome any input from this community explaining to me how I'm wrong - because it was very depressing writing it. Thx in advance - wayne

@bob wallace: If your concern is showing that solar and wind make sense, all this is true. If you are assessing what's likely to happen and its effects in the next few years, I think you're being too optimistic. First, as Joe Romm notes, because of the way it is typically produced, natural gas decreases carbon emissions per amount of resulting energy used very little -- not by 50%. Second, the US may be stopping planning for new coal plants, but because plants of a certain age are not required to have certain pollution equipment, they have been and will be kept open far past their usual lifetime. As far as China is concerned, that reduction is either a reduction in carbon emissions per unit of energy (but the amount of energy used goes up sharply) or is a pure fantasy. China has indeed increased wind and solar by large amounts, but has also increased coal by large amounts, and continues to plan to do so in the next few years. There also seems to be an assumption that small decreases in carbon emissions is the only thing that matters. No -- we also need to worry about keeping significant amounts of coal and oil in the ground for the next 100 years, if not probably the next 1000 years. At a certain point, it becomes more difficult to resequester it, no matter how much we reduce additional emissions. With regard to solar pricing, if pure price was the only criterion, you would be absolutely correct about solar's oncoming superiority to oil and coal. Our present infrastructure was built for coal and oil. Yes, you can do new infrastructure that's suited for solar on an individual basis quite effectively, but on a national and global basis, there has to be a huge superiority before the market (and governments) make the switch. Witness, for example, the delay of substitution of fiber for copper and telephone poles. This is not to say we shouldn't do this; quite the opposite. It is to say that we shouldn't be satisfied at all with "we're on our way to changing fundamentally semi-automatically." We desperately need to cordon off oil and coal resources even where people will object that they might suffer (and bend our efforts to making sure the new solar/wind doesn't make them suffer), and start solar/wind installation now even where the economics seem strongly against it -- because that pricing will turn around soon. May you be right that the ice-free Arctic causes people to fundamentally change their thinking. Unfortunately, that doesn't mean they'll fundamentally change what they do. Here's hoping they do that as well -- even if I see few if any signs of it.

@lanevn: according to Hansen, the temperature of the Earth due to the Sun's light/heat goes up by 1 degree Centigrade every billion years. While this has imperceptible effects over human time periods, it does say that (because, according to Hansen, we are apparently surprisingly near Venus' acid-rain-plus-heat life-ending "runaway greenhouse effect") the results of human carbon emissions are much more dangerous than they would have been 2 billion years ago.

I haven't seen this mentioned. The Mauna Loa global CO2 figures for 2012 are now out. They show an increase of 2.56 ppm over 2011 -- the second largest increase on record. The biggest (2.93) was in 1998 -- a far better year for the global economy. It appears that CO2 year-to-year growth is indeed accelerating. If this trend holds, we may see a daily reading above 400 ppm at Mauna Loa this year. - w

First Arctic sea ice goes, Then most of the world's ice goes, Then most of the world's cropland goes, Then 80% of our great-great-grandchildren go -- if we're lucky. What else in your life is more important than stopping using carbon?

@crandles: actually, I was looking at thickness, not volume. Otherwise, it sounds as if we are in massive agreement, if I can be said to agree with one who knows one heck of a lot more about sea ice mechanisms than I :) - w

@crandles um, pardon me for being naive, but I thought the thickness numbers you supplied me with a year or so ago settled the question. Average thickness at volume maximum since '79 has come down almost as much as average thickness at minimum -- involving increasingly late refreeze of increasingly more water gathering heat from the sun. Not so? - w

I agree wholeheartedly -- and Happy New Year, Neven. Thanks again for your wonderful efforts last year, and I hope you and yours have luck and well-deserved happiness in the new one. - Wayne

I want to weigh in as someone who has been critical of the relevant scientists in the past for talking about the "certain" rather than the "likely" and thereby not conveying the seriousness of the situation. I don't think that the solution is to deep-six the IPCC and replace it with something faster-moving. It is very valuable imho to establish certainties in this area; it's just that no effort is made today to pull together models including uncertain but likely effects like permafrost and other methane. The point is that we need something in addition, not as a replacement: models that move ahead of certainty, like Maslowskis's for arctic sea ice volume, but comprehensive, not focused on one aspect. We have the forward-looking research in areas like methane, Antarctica, and permafrost; now we need something to put it together rapidly and repeatedly. As for the way that the IPCC affects politics: again, I think the corrective is a forward-looking counterpart, else if we ditch IPCC we may find no ears listening even to the underplayed alarms.

While I have little expertise in climate change and arctic sea ice, I do have long training and "hobbyist" interest in economics. Neoclassical has effectively shown itself so far unable to adapt to recent events such as the global recession, but neoKeynesian has proven surprisingly successful. However, new challenges have arisen (my quirky summarization): (1) It is becoming apparent that extreme income inequality per Gini has bad effects not only politically but also economically -- at the extreme and during severe recessions, underinvestment in the poorest creates a larger and larger "output gap". Present macroeconomics is only beginning to recognize this, much less figure out what to do about it. (2) Pricing fails to capture "existing infrastructure" effects that lock in sub-optimal solutions. Solar is priced far higher than it should be because it is compared to oil and natural gas that takes advantage of existing gas station, grid, etc. means of distribution tuned for fossil fuels. (3) Existing economics fails to consider an interesting new concept in business agility theory called "technical debt": the idea that things deferred that must eventually be done cost far more later. Again, this applies to continuing to build oil/gas infrastructure, not to mention homes in flood zones. (4) There are serious flaws in microeconomics and macroeconomics that subtly undermine the ability to analyze the future. It is not "dynamic", in the sense that it does not allow for changes in the very constructs that underlie the model. For example, the standard microeconomic model is an industrial firm producing widgets. Look at most firms today, and there are very few workers producing physical product. Instead, most workers work on projects, like software developers. The result is a ludicrous theory of an income effect on labor, in which we are told that we will not see a corresponding improvement in production from a worker if we increase salary, because he or she will use part of the extra cash to "purchase" leisure time. I defy you to find workers who behave like this -- instead, the result of extra cash will depend on whether the worker is irrevocably in debt (no effect), working for retirement (strong effect), or rich (no effect). These flaws resulting from failure to allow a dynamic model, in turn, result in drawing exactly the wrong policy conclusion. In the case of climate change, carbon pricing mechanisms typically do not consider the possible need to combine with higher minimum wage standards and stimulus to avoid companies' tendency to squeeze out the most productive "working for retirement" workers in response. (5) While "tragedy of the commons" and "externalities" are much better appreciated now, the "future horizon" of economics is still far too short. Net Present Value, for example, typically only considers five years -- whereas in a project-oriented analysis, it is assumed that each project chosen will lead to the next. Thus, analyses in which oil exploration projects chosen now will lead to major effects on the company's infrastructure and markets 20-40 years from now simply are not modelled. Right now, however, the major problem is that the fundamental assumptions of economics about climate change that inform their projections are far from current. The best economic expert on the subject (is it Nordhaus of Yale? I can't remember) afaik continues to assume that warming beyond 2 degrees C is very unlikely, despite the fact that scientific experts are now seeing it as almost inevitable. I credit Paul Krugman of Princeton, now shown as about the best policy-analyzing economist out there, with turning me on to Joe Romm. However, even in his case I do not sense the understanding of the relation between the warming and the potential full effects on agriculture and hence on the economy, much less the relevance of analyses of how to handle natural disasters and the fact that if government cannot step in from outside because the whole world is under the same stress, the entire system just about collapses (see, for example, an Indian economist's finding that the government giving jobs that pay money instead of just giving supplies or money is far more effective). I believe that this type of economics should not be replaced but rather made to face current realities and extended in response. Galbraith's and Meadows' analyses are imho negative -- they do not suggest clearly either a new model or an extension of a model that will work better (in Meadows' case, this is apparently because she finds that all systems unless drastically revamped early break down from "overstretch"). The flaws I cite above, I believe, are remediable in relatively straightforward ways, and would result in at least some economics that had a positive role to play in our response to climate change.

I'll just delurk to make a few points, some repetitions of past years. First, Gompertz seems to me a superior way of projecting volume, as it handles the idea that ice thickness varies in somewhat of a normal fashion around the average. Thus, an exponential decrease in thickness year to year would evidence as a slower decrease in volume until the average is approached, after which there is a sharp drop followed by a multi-year (but not decadal) tail. In plain English, we're on the steep part of the volume slide, with thicknesses even in the CAB of a meter or less at minimum, but there's enough variance that perhaps 10% of the thickest ice can last for another few years. However, it seems plain to me that a similar Gompertz curve just doesn't capture the fact that in this model, area and extent are functions of volume. They will tend to stay flatter longer, and then dive more sharply. I find the idea that both will increase next year possible but unlikely. How do you get a fair amount less volume and yet more area and extent once you reach this point? It seems to me that a key test of the idea that area and extent will increase is what is happening right now during refreeze. A "bankable store" of energy from this year in the water should keep the area anomaly from shrinking rapidly -- else you would expect air temperatures below freezing and roughly comparable to last year to freeze up the ice at the same times and the same places as last year -- and we could expect greater area and extent as part of normal variation. So far, that doesn't seem to be happening at all. Am I wrong, or are both the NW and NE Passages open later in the year than ever before? What's more, the NE Passage at least seems nowhere near freezing. I would note, in passing, that the idea that the Antarctic ice area can vary widely at maximum seems to be proving out -- a temporary bulge seems to be going away rapidly, and the anomaly has gone from 1.16 to 0.45 in nine days. If both trends continue, we should be approaching record combined territory iirc in about 6 days. Anyway, I'll stick my neck out again and say that I expect volume to go below 3 mkm3, area to go below 2 mkm2, and extent below 3.2 mkm2 at minimum in 2013. Naive as ever ...

fwiw - the nsidc announcement notes the minimum could still go lower :| - w

Although I understand the Antarctic is still really off topic, I'll add my understanding of the Ross Sea ice shelf, the key WAIS "glacier blocker". It is anchored to the sea floor and therefore is a strong barrier to rapid movement of glaciers out to sea. What has been happening recently is not that it is calving, but rather that the ice shelf is melting in the middle (partway between shore and edge). Thus, at some point, the middle may simply stop acting as part of the blockage, dramatically speeding up glacier flow -- hence, I guess, the term "collapse".

If I may weigh in on SLR: Hansen has only pointed out existing data showing that Greenland melt has been doubling every decade, and that in the last decade SLR was approximately 3 cm, with the rise strongly affected by Greenland melt. If we simply double that for the next 5 decades (including this one), we're up to .5 m per decade), or about 2 1/2 meters total by 2100. If the next six decades, it's 5 meters total, which corresponds to an MIT study cited by Joe Romm a year or so ago. Note that all of these, including probably Hansen and Joe Romm, did not project summer Arctic sea ice melt before 2020, which has a strong effect on Greenland glacier speedup. Nor did they project melt to the top of the Greenland ice cap so soon. In other words, 2 1/2-5 meters may be a low estimate. If melt was doubling per decade before the sea ice blocking the glaciers is removed, what do think will happen as higher temps and ice-free coasts drive deeper into winter?

Thanks to all who have wrenched the alternative energy conversation back on a better path. I think I can add three things: 1. A very good overall picture of what's happening, I think, is the global and mauna loa measure of carbon ppm in the atmosphere. In the last three years, it seems to have neither slowed nor speeded its rise, now at about between 2 and 2.5 ppm per year. I anticipate the first mauna loa reading of 400 ppm may happen one day in May 2013. I am frankly surprised it hasn't speeded up further. 2. Joe Romm at climateprogress has, imho, a pretty good analysis of why the US decreases are not all they are cracked up to be, and do not indicate a substantial ongoing decrease in emissions. To that I'd only add that as a computer industry analyst I detect a shift in investment to "emerging countries" that often invests in less energy-efficient or more emissions-intensive technologies, and that is not captured by the way we divide up revenues between countries. Effectively, the US is outsourcing a significant part of its emissions to China and India -- which themselves (in India's case, despite their best efforts) are now pretty much the highest-emission-growth countries. 3. For those who are curious about initial thinking about housing and climate change, Joe Romm referenced an extensive study of what technologies regions of the US might consider to redo their housing as the climate changes over the next 40 years. It should be a source of ideas for all, not just in the US -- although I really hope more ideas come through in the next few years, as the document reads like a recipe for slow change of our present approach to housing.

I have been happily lurking due to the superb contributions of other commenters, but I have to delurk, because I think the comments on alternative energy are off course. Fusion -- I have been following this since the 1970s. Large amounts of money have indeed been sunk into fusion. A new promising approach has been publicized in the last year in an MIT pub, iirc. However, no one talking about it is acting as if major global rollout is going to happen any time before 40 years from now. You have to get well beyond breakeven. You have to bring the initial cost down substantially. You have to fit it to an energy grid, since it doesn't scale down. You have to deal with the usual productization -- remember, although it's not dirty, it involves extremely high temperatures. What everyone seems to be leaving out in the discussion of most other alternatives is the fact that the climate will change substantially over the next 40 years. For wind on land, what is windy now may very well not be windy 40 years from now. Wind installations presently don't move very easily. For wind on salt water, it is not beyond the realm of possibility that between 2050 and 2100, the water will rise by 15 feet, and over the next 40 years the height of waves at high tide during storms should go up 10-20 feet, and another 10-20 feet in the fifty years thereafter. Turbines are apparently not designed to cope with water drag. Geothermal is fine, but I see no one saying that it is anywhere near a solution that can handle even 30% of the world's needs. Tidal power, like wind, suffers from the problem of not being movable and rising oceans. By the way, fusion suffers from needing water as coolant, and is therefore vulnerable to loss of summer river flow from melting of land ice and warming of ocean water -- both of which have already been reported as problems today. The production of natural gas, while it cuts emissions from burning by 50%, actually cuts overall very little, because of added carbon emissions in the production process, as Joe Romm points out. The only solution for most energy (and transportation and heating/cooling) needs is solar. The cost argument is garbage, reflecting only the fact that economic analysis tends to double down on existing infrastructure, which continues to be designed for coal/oil/natural gas. The real barrier is lack of an adequate battery for medium-term storage. An MIT pub reports a new approach that seems plausible and scalable over the next 2-5 years, with luck. Along with energy efficiency, solar has to be one the two major components of an immediate and drastic deployment of a long-term and immediate solution.

In utter depression, I just wrote the following: waynekernochanblog.blogspot.com. My apologies if it's off-topic; I just couldn't find a closer match. - w

@Neven - speaking of yet more records, I note that Antarctic SIA has suddenly decided to move back to the norm - Given the possibility that Arctic SIA will move down another 300k km2, we may be staring at a record global SIA anomaly within the next week - w

@Joe Smith -- here are a few: Global Warming: Earth -- love it or leave it Global Warming: Earth -- if you can't stand the heat stay out of my kitchen Global Warming is SO the last 160 years Global Warming: Some say the world will end in fire, and some in ice. From what I've seen of human of human desire, I hold with those who favor fire. -- Robert Frost Global Warming: The Earth died for our sins. Pay no attention to the Man behind the warming. - Wizard of Oz The one good thing about Global Warming: no more Titanic jokes. Hope this helps ... - w

@AR: Fascinating Archer stuff, but not sure it does contradict what I said. Basically, I read it as: Hansen etc. say the half-life of carbon in the atmosphere (typically as CO2) is 100-200 years. The primary way it comes out of the atmosphere now is that the ocean takes it. However, we looked closely at that uptake -- there's still 30% left in the atmosphere after 200 (to 2000) years. Luckily,another molecule in the atmosphere takes away much of that - 3000 to 7000 years from now. So my read of Archer is that while the "half-life" of carbon in the atmosphere may be somewhere around 135 years (50/70 times 200 years), the majority of the rest stays around so long that "on average" the carbon stays around much longer than 135 years. I'm less concerned with "on average", and more with the next 200 years. And yes, my math is very approximate :) - w

@AD Again, sorry for not being clear. I'm trying to get at how long methane stays at a very high level in the atmosphere, which would happen if constant releases from accumulated clathrate and permafrost methane take place over, say, a 100-year rather than a 200-year period. The fact that "hydroxyl ions" are depleted, extending methane's half-life, increases the amount of methane in the atmosphere at any point in that period, and extends the period slightly. Eventually (after 100-plus years, I'm guessing), though, the accumulated methane from those sources runs out and the methane begins decreasing below the danger point. Afaik. My mental image is of a ball being kept aloft by blown air from beneath (release of clathrate and permafrost methane). Slow the blowing way down (no more methane from those sources), and the ball comes back to Earth (methane levels come back down). - w

@Alan Clark - sorry I wasn't clear about this; in fact, I'm not sure I'm representing correctly what I read. The "half-life" of methane is how long it takes for methane either to descend again to the Earth or split apart -- e.g., the C goes to CO2, The Hs go to H2O. The saturation point applies to whether there's enough O and H around in the atmosphere around the methane so that methane can be split apart that way. At any rate, that's my best guess as to why scientists say that if methane reaches a big enough level in the atmosphere, its average time aloft starts going up -- and I think what I read did use the phrase saturation point. - w