By Steve Goddard
“In everyone’s life, there is a summer of ’42 + 65”
By now, we have all been bludgeoned senseless with talk of how Arctic Ice dramatically declined in 2007 – “much faster than the models.” We were told by the experts that this rapid decline would lead to an ice-free Arctic in 2008, 2013, 2030, etc. – not to mention 1969 and 1922. I don’t buy it. The idea of an ice-free Arctic seems implausible to me without a dramatic change in climate.
Let’s start by looking at what really happened in 2007. The graph below (calculated from PIPS maps) shows the average ice thickness in the Arctic Basin for 2006 – 2008. Note that the average thickness of the ice in 2007 was fairly constant through the spring and summer. In fact, 2007 had the largest average summer thickness. This is solid evidence that the low extent in 2007 was primarily due to horizontal melt and compaction of the ice, rather than vertical thinning.
Given that there was no change in average thickness, in order for the ice to disappear it would have to melt horizontally. As you can see in the graph below, the volume loss came to a hard stop in early September. The sun is too low by September for significant melt to proceed. There just isn’t enough time in the Arctic summer for all the ice to melt.
2006 was highest in the DMI record and had 30% greater summer extent than 2007 – but the 2007 late summer ice was almost 20% thicker. 2007 was never in any danger of a complete meltdown.
The video below shows the thickening of the ice in 2007 as it compressed horizontally from the wind.
The next problem with an “ice-free Arctic” is that summer temperatures north of 80N have not changed over the last 50 years. You can see that in the DMI graphs. If anything, recent years have had colder summers near the pole. High Arctic warming has occurred in other seasons, but not during the summer. The melt season is very short at the pole, and some summers have no melt.
GISS doesn’t have much data north of 75N, but the few data points they do have show little or no summer warming.
In 2008, the North Pole started with first year ice. Mark Serreze bet that this would lead to an ice-free pole. It didn’t happen, in spite of relatively warm temperatures at the pole.
- An ice free pole could not occur without dramatic summer warming.
- There has been almost no summer warming in the high Arctic over the last 70 years.
- The melt season is too short to have an ice free Arctic. Roger Pielke Sr. did a study which shows that the length of the melt season has not changed significantly.
- 2008 started with first year ice at the pole. It was a warm summer at the pole, and the ice did not disappear. There will never be a summer which starts with younger ice than 2008.
- Linear projections of an ice-free pole are incorrect. It is much more likely that the slope will tail off asymptotically.
- I propose that 2008 ice volume was close to the theoretical minimum, until Arctic summer temperatures increase dramatically.
- Dress appropriately the high Arctic. It is too cold for a bikini.
(Everyone agrees that PIPS2 is the best available data source of historical ice thickness. Please don’t start another conversation about that topic.)