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Polar Bear Politics A case study in forecasting

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Polar Bear Politics A case study in forecasting Anna Whelan, Orkney Islands Council Forecasting and Projections Workshop Analysts Network, 1 July 2010 – PowerPoint PPT presentation

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Title: Polar Bear Politics A case study in forecasting


1
Polar Bear PoliticsA case study in forecasting
  • Anna Whelan, Orkney Islands Council
  • Forecasting and Projections Workshop Analysts
    Network, 1 July 2010

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The Sunday Times, December 18, 2005 Polar bears
drown as ice shelf melts Daily Mail, 01 February
2007 Global warming sees polar bears stranded on
melting ice Daily Telegraph, 15 Sep 2008 Polar
bears 'could become extinct' because of melting
ice, scientists claim
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  • Al Gore, March 22, 2007
  • Their habitat is melting beautiful animals,
    literally being forced off the planet. Theyre in
    trouble, got nowhere else to go.

9
Should polar bears be listed under the US
Endangered Species Act?
  • Nine administrative reports were commissioned by
    the US Geological Survey in 2007 to Support
    U.S. Fish and Wildlife Service Polar Bear Listing
    Decision.
  • Listing decisions are made on the basis of
    long-term population forecasts
  • The reports contained forecasts of polar bear
    populations for 2045, 2075 and 2100

10
Forecast methodology
  • Forecasts used IPCC (Inter-governmental Panel on
    Climate Change) GCM (general circulation model)
    projections of the extent of sea ice in the
    Arctic
  • GCM assumes that Arctic ice melt in recent years
    results from global warming
  • Sea ice forecasts used as one of several
    variables in population variability analysis
    (PVA)

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12
  • http//scienceandpublicpolicy.org/videos/armstrong
    _testimony.html

13
  • J. Scott Armstrong, Kesten Green WillieSoon
  • Polar Bear Population Forecasts
  • A Public-Policy Forecasting Audit
  • Interfaces Vol 38 no. 5 Sep-Oct 2008

14
  • To make policy recommendations based on
    forecasts, the following assumptions are
    necessary
  • (1) Global warming will occur and will reduce the
    amount of summer sea ice
  • (2) Polar bears will not adapt thus, they will
    obtain less food than they do now by hunting from
    the sea ice platform
  • (3) Listing polar bears as a threatened or
    endangered species will result in policies that
    will solve the problem without serious
    detrimental effects and
  • (4) Other policies would be inferior to those
    that depend on an Endangered Species Act listing.

15
How valid were the assumptions?
  • No scientific evidence for global warming
    forecasts
  • IPCC GCM sea ice forecasts are inaccurate from
    1990 to present day
  • Sea ice has decreased in the northern hemisphere
    and increased in the southern hemisphere
  • NASA research indicates cause of Arctic ice melt
    to be a change in wind patterns

16
Armstrong principles cited
  • Make forecasts independent of organizational
    politics
  • Use all relevant data
  • Use the most recent data
  • Use simple forecasting methods
  • Be conservative in situations of high uncertainty
  • Match the forecasting method(s) to the situation

17
Expert forecasts are of no value in complex and
uncertain situations, because of
  • (1) Complexity People cannot assess complex
    relationships through unaided observations.
  • (2) Coincidence People confuse correlation with
    causation.
  • (3) Feedback People making judgmental
    predictions typically do not receive unambiguous
    feedback that they can use to improve their
    forecasting.
  • (4) Bias People have difficulty in obtaining or
    using evidence that contradicts their initial
    beliefs. This problem is especially serious among
    people who view themselves as experts.

18
BBC Five live Interview with Scott Armstrong
during the International Conference on
Climate Change on March 9, 2009 Host So what
did your research actually say?... Professor
Well people arent sure how many polar bears
there are but there seems to be a consensus that
theyve been growing in numbers over the past few
decades... Host Weve got a guy here, a very
esteemed TV broadcaster and zoologist, David
Attenborough. I dont know if you know him,
Scott. He put out this most heart wrenching
documentary on the TV on national telly about a
month ago showing the polar bears starving to
death, the ice slopes melting, they cant get to
the seals anymore, populations in decline. So
David Attenborough wouldnt be lying to us, would
he?
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Polar bear populations
  • 19 delineated polar bear sub-populations
  • 5 are declining
  • 5 are stable
  • 2 are increasing
  • 7 have insufficient data to observe a trend
  • Estimated total population 20-25,000

21
The Daily Telegraph, 27 Jun 2009 Polar bear
expert barred by global warmists Top of the
agenda at a meeting of the Polar Bear Specialist
Group will be the need to produce a suitably
scary report on how polar bears are being
threatened with extinction by man-made global
warmingBut one of the world's leading experts on
polar bears has been told to stay away from this
week's meeting, specifically because his views on
global warming do not accord with those of the
rest of the group.
22
  • Taylor, Mitchell and Dowsley, Martha
  • Demographic and Ecological Perspectives on the
    Status of Polar Bears
  • Science Public Policy Institute, March 2008

23
Taylor and Dowsley
  • The concern that polar bears will decline if
    the climate continues to warm is valid. However,
    the assertion that polar bears will become
    extinct unless immediate measures are taken to
    curb greenhouse gas emissions is irrational
    because it is inconsistent with the long-term
    persistence of polar bears through previous
    periods of warming and coolingCurrently polar
    bears are abundant and in no danger of
    extinction

24
Taylor and Dowsley contd
  • Observations of natural mortality,
    intra-specific aggression, poor condition and
    even healthy bears in good condition on ice floes
    have been cited as evidence of population impacts
    on polar bears due to declining sea ice
  • Anecdotal information, although useful and
    interesting, is not equivalent to scientific
    information based on valid statistical analysis
    of sample data.

25
Taylor and Dowsley contd
  • traditional ecological knowledge (TEK) from
    Inuit has been largely ignored because TEK is
    mostly oral, and because TEK generally does not
    support the assertion that polar bear populations
    are in general, or even local decline.

26
Taylor and Dowsley contd
  • The popular notion that polar bears are
    declininghas been initiated and perpetuated by
    environmental organisations and individuals who
    apparently believe that current subpopulation
    numbers and trends are an insufficient basis for
    an appropriate status determination.

27
Taylor and Dowsley contd
  • Neither the demographic nor ecological
    perspectives suggest any conservation benefit
    from a premature decision to list polar bears as
    a threatened species.
  • The negative conservation implications from a
    premature up-listing include loss of scientific
    credibility, loss of support from aboriginal
    harvesters, and perhaps even reduced support for
    the Endangered Species Act as conservation
    legislation.

28
Forecasting methods
  • Quantitative forecasting information is recorded
    externally and used explicitly
  • Judgemental forecasting information is recorded
    in human memory and used intuitively or implicitly

29
Quantitative bias
  • Quantitative methods are objective and involve
    the identification and extrapolation of
    established patterns or existing relationships.
  • Simple regression equation
  • Actual a ß forecast error
  • Coefficients a and ß are a measure of the bias
    observed in the forecasts compared with the
    actual values

30
How valid were the assumptions?
  • No scientific evidence for global warming
    forecasts
  • IPCC GCM sea ice forecasts are inaccurate from
    1990 to present day
  • Sea ice has decreased in the northern hemisphere
    and increased in the southern hemisphere
  • NASA research indicates cause of Arctic ice melt
    to be a change in wind patterns

31
Long term quantitative forecasts
  • Three phenomena in particular affect accuracy at
    longer lead times
  • 1. many patterns are irregular and contain a
    high level of randomness
  • 2. regular patterns may change over time
  • 3. the forecasts themselves may influence the
    future
  • Evaluation is difficult because changes may occur
    post-forecast in the situation under review.

32
Henry Mintzberg
  • Long-range quantitative forecasting (two years
    or longer) is notoriously inaccurate.
  • It works only under limited conditions
  • 1 When the world is stable or the trends are
    favourable
  • 2 When the world is under the control of the
    planning organisation
  • 3 When the policy adopted is one of scenario
    building followed by contingency planning
    provided that the number of possible options is
    known and limited
  • In all other circumstances the predetermination
    assumption of planning proves to be a fallacy

33
Judgemental forecasting
  • Requires no past data
  • Can take into account future events (both known
    and anticipated
  • Be aware of the framing problem is the
    forecaster trying to
  • - predict the outcome precisely
  • - set an aspirational target
  • - err on the side of caution?

34
Judgemental bias
  • It aint so much the things we dont know that
    gets us into trouble. Its the things we know
    that aint so.
  • Artemus Ward (1834-1867)

35
Judgemental bias
  • Belief bias tendency to generate forecasts
    which confirm to prior beliefs and to be more
    critical of conclusions which conflict with
    beliefs
  • Confirmation bias tendency to test hypotheses
    in a manner likely to minimise rather than
    maximise their chance of falsification
  • Illusory correlation tendency to see
    correlations which are not statistically present
    but which are expected to occur on the basis on
    theories held

36
Nah, min I dont really buy intae the argument
that wir winters ere gettan warse and warse
37
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38
  • Photographer was Amanda Byrd, a marine biology
    student on a field trip to Alaska in 2004
  • The time of year was August, summer.
  • Dan Crosbie gave the image to the Canadian Ice
    Service, who gave the image to Environment
    Canada, who distributed the image to 7 media
    agencies including Associated Press.
  • They did not appear to be in dangerI did not
    see the bears get on the ice, and I did not see
    them get off. I cannot say either way if they
    were stranded or not.
  • I take neither stand, I simply took the
    photos...If I released the image myself, it would
    have been as a striking image. Nothing more.
  • Email from Amanda Byrd to ABC Television,
    Australia

39
  • http//www.nationalcenter.org/PolarBear.html

40
For discussion
  • Have you ever been asked to produce forecasts to
    back up a policy decision? What happens if the
    forecasts dont match the policy?
  • How is the framing problem affecting forecasts of
    the effects of public sector funding cuts?
  • Why might various parties want to over- or
    under-estimate population forecasts? To which
    forms of bias might they be susceptible?
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