Who thinks the Arctic will refreeze this year to the 1979 level?

Well I'm just going to assume you're talking about Arctic sea ice extent (area) and not volume. There's no question whatsoever that Arctic sea ice volume will be far, far below 1979's levels, because the new ice which is now re-forming is very thin.

As for extent, I would also say no from just looking at the data.

http://nsidc.org/data/seaice_index/images/daily_im...

In order to recover back to 1979 levels, the current trend would have to continue for another full month. Just look at the 2007 trend - it started to slow down well before the end of October.

Yes, the ice is recovering rapidly right now, but I don't see any reason to assume that this rate will continue for another full month. Nobody has given me any reason to expect this to be the case.

Also, just look at the long-term trend:

http://nsidc.org/data/seaice_index/images/n_plot.p...

To expect this to suddenly jump back up to 1979 levels seems completely unrealistic.

And regardless, volume is more important than area. If the volume doesn't recover, the new ice will just melt again next summer.

Do you mean as an yearly average 1979 level, winter average or a specific day (October 31th?)

Do you mean area or volume?

To make any useful conclusions the only thing that matters is averages and volume so my answer to your question will be no.

For the ice area issue: Yes maybe,since cold water freezes faster than warm water and there's a lot of cold water from the record melt of ice in August. "August saw its largest seasonal melting since satellite observations began 30 years ago."(from the link below)

Please Mikira: Here's an article for you and those of you who believe the warming has stopped:

"Arctic Autumn temperatures hits record high": http://news.yahoo.com/s/afp/20081017/sc_afp/usclim...

Quote: "2007 was the warmest year on record in the Arctic region, followed closely by 2008. This continues a general Arctic-wide warming trend that began in the mid-1960s."

If we reach 1979 levels I'd be surprised. 1979 was the last of a long series of years with descending temperatures, so the ice then had been building over a number of years.

If we're coming off less than normal sea-ice years, it probably won't build to that level for some time.

Lacking a crystal ball I can't answer whether it will or it won't.

The trend seems to be that whatever Dr. Hansen says will happen, the opposite happens, so if I have to take a position I'll say whatever is the opposite of Dr. Hansen's prediction is what will happen.

What I know is this - if the arctic ice levels expand to or even near the 1979 levels, you won't hear about it in the mainstream media, and the folks at realclimate will have a non-retort retort like "well now ice cover doesn't matter and ice thickness does" even though it's ice cover that reflects the sunlight and it's ice cover that, while that bolstered their case, they said was the important factor to consider; or they might, if the ice cover at the south pole is retreating faster than average, focus on that.

NASA noted that one-year ice coverage grew while the perenial, old sea ice continued its alarming decline. NASA offers a lot of information on sea ice if you are interested. (Actually, everyone should be interested.)

The 2008 season strongly reinforces the thirty-year downward trend in Arctic ice extent. The 2008 September low was 34% below the long-term average from 1979 to 2000 and only 9% greater than the 2007 record (Figure 2). Because the 2008 low was so far below the September average, the negative trend in September extent has been pulled downward, from –10.7 % per decade to –11.7 % per decade (Figure 3).

NSIDC Senior Scientist Mark Serreze said, “When you look at the sharp decline that we’ve seen over the past thirty years, a ‘recovery’ from lowest to second lowest is no recovery at all. Both within and beyond the Arctic, the implications of the decline are enormous."

Good link: http://nsidc.org/data/seaice_index/images/daily_im...

Clearly we're above the 2005 level of ice mass. Interesting that the NSIDC doesn't show the graph for this year.

By the rate that the ice is gaining mass, it looks like the Arctic ice mass will be well above normal in just a couple of weeks.

While Norway and most of western europe is above freezing, as they always are at this time, northern Russia and Alaska are experiencing well below freezing and far below average temperatures for this time.

This cold is what is causing the ice to grow at record levels.

although it is refreezing very nicely, i dont think it will be back to '79 levels this year. the nsdic graph

http://nsidc.org/data/seaice_index/images/daily_im...

is showing an encouraging speed of freeze, and we might get back to the 79-00 average, but do bear in mind this is new ice, we need a few continuous years of cooler conditions, or it wont get a chance to thicken up into perennial ice.

http://nsidc.org/images/arcticseaicenews/20080924_...

It's hard to say. It will almost certainly beat last year's extent. But just eyeballing the images it seems like it needs to make up several thousand square kilometers to match 1979. Since it only has two weeks to do that I'll go ahead and bet that it won't.

Jello said: "Interesting that the NSIDC doesn't show the graph for this year."

All Jello had to do was look! I fail to see, and so will everyone else, that we will be above the 2005 average. Jello loves to make predictions as a lay person, but hates it when scientists do it.

http://nsidc.org/data/seaice_index/images/n_plot_h...

Given your last link, I'd say we most likely won't cross the 1979-2000 average this year. If this cooling trend continues through next year, 2010 could very well exceed that average.

...and I hate always being right. Such a cooling trend will most certainly cause further economic hardship as we try to recover from this recent downturn.