I am eagerly awaiting the September update of the Arctic Sea Ice Volume numbers. In the mean time, thank you, Doc Snow and Jim Hunt for keeping the sea ice extent numbers updated. I know that some of you would like to see a record low extent or volume in order to alert the world to the impending climate crisis, but for the same reason, I'm hoping no record is set as personally I'm not convinced that CO2 is really the climate culprit. G Man, I think you gave in too quickly. You said, "Doc I don't see it as a "triumph" at all. 2012's record low was mostly dependent on the Arctic cyclone, a weather event. It wouldn't be a stretch to say that this years ice extent without the cyclone is even lower." But, if we go back and look at March, 2019 looked like it was actually going to be a pretty healthy year insofar as Arctic ice is concerned. Wasn't it an Atlantic cyclone that knocked 2019 off track to begin with? If that is the case, what good would it do to crow about 2019 if a record were indeed set? Wouldn't that be a bit misleading? Which is why I hope no record is set, though we are dangerously close to record territory.

Thanks for the update! I've been checking this site daily for a while to see when the update would come. Glad to see this year continues to be good for ice making.

The arctic sea ice looks like Antarctica?

With all due respect to my interlocutors, correlation isn't causation. One would expect the CO2 level to rise with ocean temperature because the solubility of the ocean decreases as its temperature rises. A rise in ocean temperature would also account for a decrease in arctic ice extent. So, one would expect the level of CO2 in the atmosphere to be negatively well correlated with arctic sea ice volume, even if the relationship is not causal. So, what might be causing the rise in ocean temperature? Perhaps, it's just hysteresis. Every summer, the solstice occurs around June 21st, but the hottest day of the summer usually occurs some time in July or August, depending upon where you are in the country. Why? Because of hysteresis. The current temperature depends not only on the current forcing function, but on its past history and the history of the temperature of the land. Moreover, the amount of hysteresis tends to depend upon the amount of water nearby. In a place like Colorado which is semi-arid, there is very little hysteresis and the hottest days of the year sometimes occur in late June, though usually in July. In the Midwest, it's usually in July. In California, near the coast, it is usually even later. The ocean as a whole is very slow to heat and cool. So, even though the solar forcing function peaked some time ago, one shouldn't jump to the conclusion that the ocean is not still warming as a result of solar forcing. I don't know how much hysteresis is in the system, but it wouldn't surprise me if the trends we are seeing in global climate change have a lot to do with such factors. It is possible that the land temperature has ceased to increase because it is not effected as much by hysteresis but that the ocean is still warming because it is such an enormous heat reservoir. Of course, the ocean will affect the land and vice versa, but won't necessarily overwhelm local conditions. At any rate, if hysteresis is a large factor, one wouldn't necessarily expect to see a strong correlation between solar irradiance and surface temperature over a relatively short time frame. Every year between June 21st and the time the temperature reaches its maximum later in the summer, the average daily insolation (if you prefer) is negatively correlated with the temperature change. So, the fact that the average yearly insolation is negatively correlated with the mean surface temperature change since the time of the most recent solar maximum doesn't mean much if taken in isolation.

The trend in sea ice over the last 30-some years certainly appears to be negative, but surely no one believes that a linear model is appropriate over an extended period of time. The stock market was in a down trend from September 19th to Oct 9th that looked just as convincing as the graph above, but since then, it sold off big and then rebounded to even higher highs. Likewise, the market has been in an even larger linear uptrend for the last three years, but surely no one thinks that will last forever. I have no idea whether the sea ice will continue to get thinner or whether it has already started to thicken, but a 30 year trend line doesn't tell a person much. If solar irradiance continues to decline, I would bet the ice will continue to get thicker, but I have no way to predict solar irradiance either. Just my 2 cents worth.