Reposted from Dr. Susan Crockford’s Polar Bear Science
Posted on February 24, 2020 |
Google says many individuals ask this query so right here is the right reply: polar bears will not be going extinct. If in case you have been informed that, you could have misunderstood or have been misinformed. Polar bears are well-distributed throughout their out there habitat and inhabitants numbers are excessive (formally 22,000-31,000 at 2015 however probably nearer to 26,000-58,000 at 2018): these are options of a wholesome, thriving species. ‘Why are polar bears going extinct?’ accommodates a false premise – there isn’t any must ask ‘why’ when the ‘polar bears [are] going extinct’ half isn’t true.1
It’s true that in 2007, it was predicted that polar bear numbers would plummet when summer season sea ice declined to 42% of 1979 ranges for eight out of 10 years (anticipated to happen by 2050) and extinct or almost so by 2100 (Amstrup et al. 2007). Nonetheless, summer season sea ice has been at ‘mid-century-like’ ranges since 2007 (with 12 months to 12 months variation, see NOAA ice chart under) but polar bear numbers have elevated since 2005. The anticipated catastrophe didn’t happen however many individuals nonetheless consider it did as a result of the media and a few researchers nonetheless give that impression.
The prediction of imminent extinction of the polar bear was an utter failure, as I’ve proven on this scientific paper (Crockford 2017) and my most up-to-date e-book, The Polar Bear Disaster That By no means Occurred.
Look at the proof and you will notice that claims of polar bears going extinct are merely not true. Thus far, the response of polar bears to current ice loss means that they’ll proceed to thrive with even much less summer season ice than there was in recent times so long as ice in winter (December-March) and spring (April-June) stays moderately ample, as has been the case to this point. The newest data out there is summarized within the upcoming State of the Polar Bear Report 2019, to be launched 27 February 2020 however see additionally the 2018 report (Crockford 2019b).
The graph under was constructed by NASA sea ice professional Walt Meier and revealed by the US Nationwide Snow and Ice Information Middle in early October 2019. It reveals clearly that summer season sea ice (measured as the common for September) has not declined additional since 2007 however has had a flat pattern.
The graph under is from my e-book and reveals the expansion of worldwide polar bear numbers for the reason that 1960s. The ultimate estimate 26,000-58,000 or 39,000 common) is my believable and scientifically defensible ‘finest guess’ based mostly on extrapolation of current survey outcomes, summarized right here and defined intimately in my e-book.
One among Google’s prime ‘suggestion’ after I seek for the time period ‘polar bear’ is an inventory of questions that folks supposedly ask essentially the most (‘Individuals additionally ask’), together with ‘Why are polar bears going extinct?’
The ‘reply’ offered isn’t an precise reply however a press release from WWF, an multi-national group financially invested in selling the concept polar bears are struggling resulting from declining sea ice: it’s paid Google promoting meant to appear like solutions and info:
‘Due to ongoing and potential lack of their sea ice habitat ensuing from local weather change, polar bears have been listed as a threatened species within the US below the Endangered Species Act in Could 2008. The survival and the safety of the polar bear habitat are pressing points for WWF.’
Word the assertion misleadingly says ‘sea ice’ when it actually means ‘summer season sea ice’ – the predictions of potential polar bear inhabitants decline have been based mostly completely on summer season ice (Amstrup et al. 2007; Crockford 2017, 2019).
As I mentioned above, ‘Why are polar bears going extinct?’ accommodates a false premise – there isn’t any must ask ‘why’, when the ‘polar bears [are] going extinct’ half isn’t true. This submit is for the individuals who search the web considering that polar bears actually are going extinct.
One other query Google gives is: ‘What number of polar bears are left?’ Reply [my bold]:
‘In truth, the World Large Fund for Nature (or WWF) estimates that there are solely 22,000 to 31,000 polar bears left on this planet. Jan 25, 2019’
Solely? This international estimate, offered by the IUCN Crimson Listing (not the WWF) means there are nearly thrice extra polar bears than the 10,000 or so there have been in 1960 (Regehr et al. 2016; Wiig et al. 2015). However the Crimson Listing determine consists of out-of-date estimates and low-balled guesses for most of the 19 subpopulations and my e-book (Crockford 2019) explains why this 2015 estimate sanctioned by the IUCN was nearly actually too low.
Amstrup, S.C., Marcot, B.G. & Douglas, D.C. 2007. Forecasting the rangewide standing of polar bears at chosen occasions within the 21st century. US Geological Survey. Reston, VA. Pdf right here
Crockford, S.J. 2017. Testing the speculation that routine sea ice protection of Three-5 mkm2 ends in a higher than 30% decline in inhabitants measurement of polar bears (Ursus maritimus). PeerJ Preprints 19 January 2017. Doi: 10.7287/peerj.preprints.2737v1 Open entry. https://peerj.com/preprints/2737/
Crockford, S.J. 2019. The Polar Bear Disaster That By no means Occurred. International Warming Coverage Basis, London. Out there in paperback and e book codecs.
Crockford, S.J. 2019b. State of the Polar Bear Report 2018. International Warming Coverage Basis Report 32, London. pdf right here.
Regehr, E.V., Laidre, Ok.L, Akçakaya, H.R., Amstrup, S.C., Atwood, T.C., Lunn, N.J., Obbard, M., Stern, H., Thiemann, G.W., & Wiig, Ø. 2016. Conservation standing of polar bears (Ursus maritimus) in relation to projected sea-ice declines. Biology Letters 12: 20160556. http://rsbl.royalsocietypublishing.org/content material/12/12/20160556
Wiig, Ø., Amstrup, S., Atwood, T., Laidre, Ok., Lunn, N., Obbard, M., et al. 2015. Ursus maritimus. The IUCN Crimson Listing of Threatened Species 2015: e.T22823A14871490. Out there from http://www.iucnredlist.org/particulars/22823/zero [accessed Nov. 28, 2015]. See the complement for inhabitants figures right here.