While AP’s resident alarmist Seth Borenstein reports
“The polar bear is us,” says Patricia Romero Lankao of the federally financed National Center for Atmospheric Research in Boulder, Colo., referring to the first species to be listed as threatened by global warming due to melting sea ice.
WUWT reader “Windsong” writes:
Dr. Susan Crockford has a timely post on her site today about the International. Union for Conservation of Nature/Species Survival Commission (IUCN/SSC) Polar Bear Species Group walking back the basis for polar bears being listed as “threatened” in the U.S.
But now, in an astonishing admission, the PBSG have acknowledged that the last population survey for the SB (Regehr, Amstrup and Stirling, 2006), which appeared to register a decline in population size and reduced cub survival over time, did not take known movements of bears into account as it should have done.
In other words, that 2006 study almost certainly did not indicate bears dying due to reduced summer sea ice in the SB, as biologists said at the time — and which they presented as evidence that polar bears should be listed by the ESA as ‘threatened’ — but reflected capture of bears that were never part of the SB subpopulation and so moved out of the region.
As the PBSG said about the 2006 estimate:
“…it is important to note that there is the potential for un-modeled spatial heterogeneity in mark-recapture sampling that could bias survival and abundance estimates.” [my emphasis]
“Spatial heterogeneity” means that the sampled bears could have come from more than one population, a possibility which violates a critical requirement of the statistics used to generate the population and survival estimates. “Un-modeled” means that the ‘movement of bears’ problem was not factored into the mathematical models that generated the 2006 population size and survival estimates as it should have been.
What’s shocking is that the PBSG have now admitted that the ‘movement of bears’ issue essentially invalidates the 2006 population estimate and the much-touted ‘reduced survival of cubs.’ The reduced survival of cubs data from that SB study was a critical component of the argument that US bears were already being negatively impacted by global warming and thus, should be listed as ‘threatened’ under the ESA (US Fish & Wildlife Service 2008).
More at http://polarbearscience.com