Brad Delong wields the delete key to maintain the faith of his flock

Summary: It’s his website, and can delete comments at will. But the persistent deleting comments that challenge the faith of their flock shows insecurity. Or perhaps awareness that his (and their) faith rests on weak foundations. Deleting comments is a common practice among leftists and AGW-advocates (e.g., RealClimate), one seldom found on conservative websites (see update at the end). Make of this what you will.

On Sunday Brad DeLong’s (Prof Economics, Berkeley) website linked to the 21 August sea ice extent page of the National Snow and Ice Data Center, with the headline “The Northwest Passage Is Open!” True, but as always context is king. The very act of deleting information tells us something about both the deleter and his cause. {Note: DeLong is a brilliant economists, often quoted on the FM website. Climate change is a different realm. Secular or religious, depending upon the individual.}

The rapidly deleted comment noted that the western age of arctic exploration took place when the little ice age held the northern hemisphere in its grip. The warming over the past two centuries makes the opening of the northwest passage inevitable. And so we’ve seen. The Amundsen (1906) and Larsen (1944) expeditions made the passage, although both got locked in the ice. Since then the passage has become easier (for links giving additional information, see Wikipedia). Some of those making the trip:

the 45 foot steel yacht Williwaw in 1977
the passenger ship MS Explorer in 1984 (ice rating 1C, 4th of 6 levels for traveling the Baltic Sea)
the 18-foot catamaran Perception in 1986-1988 (over several summers, by sail only)
the 47 foot aluminium yacht Northabout in 2001 (sailboat with a diesel engine)
the 42 foot steel yacht Norwegian Blue in 2003
the cruise ship MS Bremen in 2006

We have little data on sea ice extents before the satellite record begins in the 1970’s. The northwest passage may have frequently opened during the warm Medieval era.

More information DeLong probably does not want his readers to know

First, unusually high ice down South, as shown by the following graph from the National Snow and Ice Data Center, as of 21 August:

The net of arctic ice loss and antarctic ice gain has been little net change. As seen in the following graph from Cryosphere Today (Dept of Atmospheric Sciences at the U of Illinois) as of aprox 21 August. To more easily read it: click on the link, save the graph, open the file, magnify the image. The global sea ice area is approximately average for the 1979 – now period. Note that the poles might have different impacts on global climate. This is widely asserted, but I’ve found little discussion of it in the literature (If you have some citations, please send them using the comment form — to be posted here).

For current data on polar sea ice (remember there are two poles) see here, combining current data from the major data collection institutions.

Update

Comment from a reader: “{Many} conservative websites, including the Small Wars Journal, Big Government, and Powerline, routinely delete comments they don’t like.”

Does this disprove the description “a practice seldom found on conservative websites”? Also, the SWJ IMO is a counter-example. I participated in many intense discussions there — eventually getting banned. Not only were no comments deleted, later they lifted the ban and added the FM website to the blogroll. These days its rare to see people changing their minds; it shows that they’re big people over at the SWJ.

Other posts about sea ice and climate change