Watts Up With That?

How can we call the current warming "global" when the southern half of the planet is cooling? The warmers claim the MWP was a regional event. If that was the situation then the current warming is no different.

Busted URL--correct I think:
http://arctic.atmos.uiuc.edu/cryosphere/arctic.seaice.2007.update.mov

Editor note: fixed, thanks

According to Cryosphere Today, normal North Pole ice area at this time is about 5 million km^2, with current amounts amounting to a negative anomaly of about 2 million km^2, for a current total of about 3 million km^2. On the other hand, the South Pole normal area is about 15 million km^2, with current amounts amounting to a positive anomaly of 1 million km^2, for a current total of about 16 million km^2.

Now, it is easy to get alarmed about the North Pole numbers, because they have gotten so close to zero. But the truth is about 2/3rd of total North Pole ice always melts by the end of the northern summer. This summer it got down to about 1/4 of the winter amount.

It is much less alarming if you consider the total between the 2 poles. Using the Cryosphere Today normals and current ice areas, there is normally about 20 million km^2, and currently there is only 19 million km^2. When realize that the total taken together only represents about a 5% reduction from normal, then it does not seem nearly as alarming.

Nice analysis Aaron, it kind of puts the whole issue in perspective. Great graphics!

Regarding the Northern ice animation, I tried to find one for the south pole--is there one that anybody knows of?

I see you've chosen to do what denialists love to do most when confronted with truth: change the subject.

I can certainly understand that you'd rather not discuss the fact that the southern hemisphere data shows no statistically signficant trend, while the northern hemisphere not only shows a statistically signficant downward trend, the ice loss shows statistically signficant acceleration. Or the fact that southern hemisphere sea ice has broken the previous record by a miniscule 0.8%, while northern hemisphere sea ice has broken the previous record by a whopping 27%.

So I'll answer your challenge: the reason for the record southern sea ice extent is natural variation. There's no statistically significant evidence that it's anything else.

As for the northern hemisphere, the evidence is not just statistically significant, it's undeniable, that it's not natural variation. So: explain it, or shut up.

Not sure who the tamino rant was aimed at, but I would (as a seriously uninformed person) like to know are we talking about proof of man-made GLOBAL warming involving two GLOBES, one whose North-pole ice proves that man-made global warming is at work, and another GLOBE whose South-pole ice proves that man-made global warming is not at work? Is this another proliferation of humvee's is causing Martian icecaps to disappear?

Tamino says "As for the northern hemisphere, the evidence is not just statistically significant, it's undeniable, that it's not natural variation. So: explain it, or shut up."

How far back do these records go? To 1979 I presume. That is too short a time for records to be meaningful.

It is undeniable that polar amplification is not happening since the Antarctic is not warming. No polar amplification means the anthropogenic greenhouse hypothesis has been falsified. Add the lack of tropospheric warming and the fossil record showing temperature leading CO2 and the AGW hypothesis has collapsed.

It's time to end the denial Tamino. The AGW hypothesis has been falsified.

Here is an explanation:

Recent Rapid Decline in Sea Ice caused by Unusual Winds, says NASA

A few of our commentators on this blog found this story earlier today and I thank them.

Anyway, in a news release from NASA Monday, a group of scientists have determined that unusual winds caused the rapid decline (23% loss) in winter perennial ice over the past two years in the northern hemisphere. This drastic reduction is the primary cause of this summer's fastest-ever sea ice retreat in recorded history which has lead to the smallest extent of total Arctic coverage on record.

According to the NASA study, the perennial ice shrunk by an area the size of Texas and California combined between the winter of 2005 and the winter of 2007. What they found was the Arctic Ocean north of Siberia and Alaska was dominated by thinner seasonal ice that melts faster compared to the thicker ice confined to the Arctic Ocean north of Canada. The thinner ice is more easily compressed and responds more quickly to being pushed out of the Arctic by winds.

"Unusual atmospheric conditions set up wind patterns that compressed the sea ice, loaded it into the Transpolar Drift Stream and then sped its flow out of the Arctic," said Son Nghiem of NASA's Jet Propulsion Laboratory and leader of the study. When that sea ice reached lower latitudes, it rapidly melted in the warmer waters.

More at http://global-warming.accuweather.com/2007/10/recent_rapid_decline_in_sea_ic.html

Douglas Hoyt:

Nice try. Congratulations for not changing the subject.

But you haven't explained the decline in arctic sea ice. You've only offered part of the reason, and one that applies only to the last few years. It's as though I challenged you to explain why Paul McCartney is such a revered musician, but you're loathe to admit that the Beatles were a great band or that he was an outstanding singer and composer, so you reply it's because of his oscar-winning song for one of the James Bond films.

Wind patterns utterly fail to explain the decline which is clearly present from the very beginning of satellite obserations (and is strongly statistically significant). In fact, starting in late 1978 (when satellite observations began) you only have to go as far as 1986 (a trifle over 7 years) to find a statistically significant trend. Haven't you wondered why never before in human memory have "wind patterns" opened up the northwest passage? Here's a clue for you all: temperature increase.

The arctic doesn't just show a record low in sea ice this summer. It shows strong, statistically significant, persistent, accelerating, dramatic loss of ice cover ever since satellite observations began. The challenge wasn't just to explain the record low this summer; it was to explain this. You've still got some splainin' to do.

Tamino
the Artic was warmer in the 1930s than today. We just don't have satellite measurements of the sea ice from that time.

You don't prove AGW by 28-year declines in sea ice in the Arctic when Greenland's ice mass and that of Antartica are incrasing.