My erstwhile Antipodean shadow PKD has brought to my attention the June 2009 examples of the NSIDC's editorials, entitled "Melt Season Gains Momentum". His series of observations in his unique style would have been in the comments section at the bottom had I not clumsilty toasted them as I tried to update this posting.
Any one of us can be accused of cherry picking data, I am sure (even you, PKD!), so in the spirit of cherry picking let me just use the NSIDC's words and illustration, and add that May's ice extent using NSIDC data looks to be about the same as 1990 and is higher than all but four of the past 19 years. If this is a trend, I think we can live with it. NSIDC helpfully plots the downward trend from 1979, a year whose only significance is that satellite data became available, then goes on to say:
May 2009 compared to past Mays
Compared to previous Mays, ice extent in May 2009 is about average. Over the last four years, May ice extent has increased.
Here is the original blog posting from a month ago:
Give the National Snow and Ice Data Center full marks for consistency. But not for objectivity, at least not for objectively presenting their own data.
Take their May 4 2009 update of sea ice extent. The chart shows 2009 ice extent approaching the average for the period 1979-2000, which NSIDC uses as a consistent benchmark. The start of the period corresponds with the beginning of satellite measurement of ice extent. The accompanying summary states:
Arctic sea ice extent declined quite slowly in April; as a result, total ice extent is now close to the mean extent for the reference period (1979 to 2000). The thin spring ice cover nevertheless remains vulnerable to summer melt.So don't stop worrying about global warming just yet, dear reader, because this ice could melt! Could it melt more readily than spring ice from other years? Yes, NSIDC declared a month ago:
the melt season has begun with a substantial amount of thin first-year ice, which is vulnerable to summer melt.If temperatures remain below average (a condition which the NSIDC has finally acknowledged) then somehow the thin first-year ice may survive and become second-year ice, with any luck less "vulnerable to summer melt". But again, don't count on it, according to the NSIDC
...conditions may not always favor the survival of second-year and older ice. Each winter, winds and ocean currents move some sea ice out of the Arctic ocean.Reading this, one would think that once there was a patch of open water the whole place turns liquid faster than you can say "Save us, Al Gore!" This is consistent with climate modelers' worldviews that climate feedbacks are positive and once a change has been set in motion there is no stopping it.
Think about that.
In geologic time frames our plucky blue planet has been brass monkey cold, and stinking hot, and every temperature in between. If the feedbacks were positive, once we started heading towards hot we would just keep going until we made ashes of ourselves. We would not BE here if climate feedbacks were positive.
Back to the NSIDC and its little report. Recall in the opening quote that they call 1979-2000 their "reference period". This is nice and neutral. If the same organization referred to a "long term decline" in their same article, how would you think this related to the reference period?
Below is the chart that covers the putative long term decline. The astute reader will note that while it comes from the same organization, the data and trend line extend into 2009. The reader would then wonder why the last eight full years are not included in the reference data, as they would most certainly confirm that ice extent is above overall average levels calculated from all data at hand. From the chart, ice extent appears higher than any April in the last decade.
The informed reader would also observe that the beginning of the period of satellite observations coincides with the end of the cold period that began in 1940 and covered almost 4 decades during which CO2 levels steadily climbed while temperatures dropped, but that is a topic for another day. It is no wonder that ice extent started high and dropped for a while.
Trends are not destiny. Ocean temperatures and atmospheric temperatures have both signalled that the warming trends of the NSIDC reference period have reversed and heat energy is being lost from the earth and its atmosphere, not accumulating as many have been led to believe.
There is more ice now than there has been in a decade. Don't be surprised by this. And consider the possibility that there will be even more ice next year and next decade as solar activity, the Pacific Decadal Oscillation and heaven knows what other mechanisms exert their normal will on us.
Then consider whether a colder planet is such a welcome prospect. I can imagine a time within ten years when we are struggling to feed our population and someone will suggest increasing CO2 emissions to enhance crop yields and maybe warm the place up a bit.