Thursday, October 11, 2007

NASA pours cold water on one warming story.

On September 18 this blog reported on the hundreds of media stories about Arctic ice packs and their melting. The media attributed this to global warming and made all sorts of claims. The BBC, among others, reported that the ice melting resulted in the Northwest Passage being clear of ice for the first time in history. We noted that the BBC also reported the exact “first time ever” story several years earlier as well -- apparently they don’t read their own news or there was a really unusual situation of two “first” times.

Many media accounts added that this meant ships could now travel through the Northwest Passage, which has never happened before. In fact, there have been numerous cases of ships traveling through the Passage, the first over a century ago. In other words the dramatic images painted by the media, to whip up interest in their accounts of “global warming”, were bogus. It was bad reporting by the media. Warming alarmists spread the story and their lapdogs in the media lapped it up with relish never bothering to verify the claims.

Of course the rejoinder could be along these lines. “Okay, the media got the Northwest Passage angle completely wrong. And maybe it was clear of ice on at least one previous occasion. And the “recorded history” angle is deceptive since the record only started in 1978. But the basic facts are correct. Global warming is responsible for a significant reduction of Arctic ice.”

The problem with such a rejoinder is that NASA poured cold water all over it. (Pardon the pun.)

It is well known that both poles have huge amounts of ice. They experience constant sunlight for six months and constant darkness for six months. During the dark period the ice expands significantly. During the light it shrinks. So the ice packs expand and contract every year. In the Arctic the ice pack, during the summer of 2007, was smaller than has been seen since satellites started recording ice movement.

Using data from a NASA satellite a team from NASA’s Jet Propulsion Laboratory looked at the trends in sea ice. And what they found, which will be published in Geophysical Research Letters, is that “the rapid decline in winter perennial cies the past two years was caused by unusual winds.” The lead scientist, Son Nghiem says: “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.” As the ice was basically blown out of the colder region it entered warmer water where it melted rapidly.

Normally perennial ice declines by about 193,000 square miles every summer. Since 2000 it has been declining at about three times that rate. (Of course it reappears every winter.) Nghiem found that an “unusual pattern of atmospheric pressure” began at that time resulting in the winds that are pushing the ice into warmer regions thus increasing the normal levels of melting.

One result of this period of unusual wind activity is that it is causing scientists to rethink the models they use to predict what is happening. Pablo Clemente-Colon or the National Ice Center says that the models “will require new physical insights and understanding of complex Arctic processes and interactions.”

But what is happening at the other pole: the Antarctic. The media has been pretty quiet about that. No press releases, no scary headlines of late. The Antarctic goes through the same sort of expansion and contraction process.

Satellite data since 1978 shows that during the summer the ice pack contracts to around 2 million square kilometers. It has been as big as almost 3 million sq. km. and it has been as small as almost 1 million. It was at its smallest summer level in 1993 and at the largest level in 2004. (Again remember there is no data prior to 1978 so no one knows what happened before that time.)
During the winter expansions the ice pack has been as small as about 14.5 million sq. km. and as large as just over 16 million sq. km.. Most the time it comes in around 15 to 15.5 million: this has been true for 22 of the 29 years since records were kept. During seven years of this period it was closer to 16 million, that includes the last three years. The record year for ice expansion, during the winter, is this year.

The reality is that while one pole saw massive ice reductions, due to wind conditions, the other pole saw ice packs expand to record levels. I suspect that the media won’t mention the Antarctic as long as ice packs are expanding. It is inevitable that one year the ice will be smaller than a previous year and when that happens the media will pounce on the story once again.

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