Without fanfare of any kind (so far), the IUCN Polar Bear Specialist Group (PBSG) has just announced, via a notice posted on its website, that it has revised the population estimate for polar bears to 18,349 (range 13,071-24,238), based on a new status table posted today.
The average is down slightly from the 2009 estimate of 19,747 (which was officially stated as “20,000-25,000″), but that “decline” is an illusion.
As for the 2005 and 2009/2010 status tables, they do not add up the columns to give the totals — you have to do that yourself, which is how I got the numbers above. There is no mention of a change to the global estimate total in any of the “announcements” on their website.
As occurred in 2005 and 2009, an overall reduction in the total was achieved primarily through removal of an estimate present on their tables since 1993 (Laptev Sea, “800-1200″). Changing this estimate to zero reduced the average total by 1,000 but does not reflect a real-world change.
In addition, four subpopulation estimates were reduced, three of them only slighty (details below) and three subpopulation estimates (Foxe Basin, Western Hudson Bay and Southern Hudson Bay) were increased to reflect recent aerial survey results. Two others were increased slightly.
A new column has been added to the status table, again without explanation, called the “Trend relative to historic level (approx. 25-yr past).” Although only seven out of 19 subpopulations had anything like an accurate estimate in 1989, four are now considered to have been “not reduced” while three are considered “reduced.” Why this is considered meaningful enough to add to the table is not clear.
The PBSG say they have decided to update the status table independent of their meetings, which means that no written report or document will be made available to explain any changes — the “justifications” will only be available online.
These are the people we are supposed to trust to provide honest and accurate information about the status of polar bears worldwide. The changes in the status table provided today, which have been made without oversight of any kind, hardly inspire confidence in the information they provide. See what you think.