Lomborg-errors:
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Polar bears: canaries in the cage? |
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POLAR BEARS |
List of
errors in
Lomborgs text:
GROUNDLESS
DEROGATION
Page 2 bottom, page 4 top and page 4 bottom: "The World Wildlife Fund
actually warns that polar bears might stop reproducing. . ."; "It has
gotten much press that . . . Not mentioned
though, is that . . " and "Yet we are told that global warming will
make polar bears extinct, possibly within ten years. . "
Error:
The quote on page 2 from
Washington Post of what WWF said is not correct. WWF was quoted for
saying that bears in Hudson Bay
might stop reproducing by 2012. This is a correct citation of what
scientists say (except that it should have been only the western Hudson
Bay). But Lomborg distorts the citation and make us
believe that WWF said that polar bears - worldwide - would go extinct
within ten years. Actually, when you consulted the WWF web pages as
they appeared in 2006-2007, you saw a very different picture.
There was a balanced
presentation of what populations are declining, now and formerly, and
what populations are increasing, now and formerly. The news story on
decline in the Western Hudson Bay was presented as just what it was -
one
story from one limited part of the distribution range. There was one
page on hunting (this version was indeed placed on the internet already
when
Lomborg was writing his book) stating that the main threat to polar
bears remains over-hunting. The present version of the WWF
web
pages is changed relative to 2006. Now, retreat of sea ice, rather
than hunting, is mentioned as the most serious threat, probably in
accordance with changes in the real world since 2006. Still, however,
the web site also contains a pdf document stating that overharvesting
is the most serious threat. It is still true, as it was in 2006, that
you get much better and more
balanced information on polar bears on the WWF web pages than the information in Cool
it, which is based on data that partly were outdated already when
Lomborg wrote it, and partly are not founded in scientific facts.
This text has been written by Lomborg in bad faith. He has consulted
the WWF web site and knows what it said. WWF have never said that
"global warming will make polar bears extinct, possibly within ten
years". This is Lomborg´s deliberate
distortion of what they said. We have here a case of deliberate
groundless derogation. Read more here about why Lomborg does that.
(COMMENT)
Page 2 bottom: " . . polar bears will be consigned to history . . ."
Comment: It is true that
Catarina Cardoso from WWF in UK is cited for this in a BBC news web
site. However, it is evident from that web site that she is speaking of
the situation by the end of the century, when the summer sea ice will
have disappeared completely. Lomborg, however, places the quote in such
a contexdt that the reade may think that she speaks of the situation in
less than a decade.
FLAW OF CITATION
Page 2 bottom: "The IUK Independent tells us . . . "
Flaw:
The source that Lomborg gives does not contain the cited sentence.
(COMMENT)
Page 3 top: " . . research published in 2001 by the Polar Bear
Specialist Group . . ."
Comment: The link given
by Lomborg does no longer work. A functioning link is here.
FLAW
Page 3 top: ". . . of the 20 distinct populations of polar bears . . .
one or possibly two were declining in Baffin Bay; more than half
were known to be stable; and two subpopulations were actually increasing
around the Beaufort Sea."
Flaw:
This information is taken from the 13th specialist meeting in
2001. However, knowledge of population size and trends was still not
very certain at that time, and declines because of changed ice cover
were not yet clearly evident. Data from the 14th specialist meeting
in 2005 are different: out of 19 populations, 2 are
increasing, 5 are declining, 5 are stable, and for 7 the trend is
unknown due to lack of data. Lomborg should have used the most recent
evidence. The proceedings of the 14th specialist meeting were placed on
the internet in November 2006. Lomborg has a reference to the polar
bear
specialist group homepage. This homepage put a message on 15-Dec-2006
telling that the proceedings from the 2005 meeeting in Seattle have
been published and can be downloaded. We know that Lomborg was still
writing on
the polar bear issue in January 2007, so he had time to use the most
recent information, but he did not.
FLAW
Page 3 top: ". . . more than half
were known to be stable; and two subpopulations were actually increasing
. . ."
Flaw:
This information is taken from the 13th specialist meeting in
2001. The number
of populations known to be
stable at that time was 8, which is less than half.
FLAW
Page 3 top: "actually increasing
around
the Beaufort Sea"
Flaw:
The most recent report says for the southern Beaufort Sea that although
the point estimates (1,800 around 1997 and 1,525
after the turn of the century) "suggest a decline in numbers, the
overlap of the current
confidence interval with the previous point estimate prohibits an
unequivocal statistical conclusion . . ". As for the northern
Beaufort Sea, the report says that new data will be available in
2006. Until the new estimate appears, no conclusions can be
drawn.
ERROR
Page 3: "Moreover, it is reported that the global polar-bear population
has increased
dramatically over the past decades, from about 5,000
members in the 1960s . . ."
Error:
This is not true. As explained at the top of this page, the figure of
5,000 animals is the lower limit of the first estimate given by
Uspenskii, which was later raised by himself to a figure
between 10,000 and
20,000.
Although the true figures are not known with any certainty, all
evidence is that they were not as low as 5,000.
When you read Lomborg´s text, it first refers to the 2001 meeting
of the polar bear specialist group, and then goes on to say `it is
reported´. The reader may be misled to believe that it was
reported by that specialist group. Only if you consult note 23, and
look up the reference (Krauss, 2006), you detect that the source for
the figure of 5,000 s is not the specialist group, but an article in
the New
York Times. This article is an interview with people who want to
increase the hunting pressure and mobilize all the arguments they can
for this. Their reference to the figure of 5,000 is given as `Other
experts´ - we are not told who these experts are. That - unnamed
experts referred to briefly in a newspaper article - is the only source Lomborg has for his
figure of 5,000 bears, a figure that is crucial to the whole point he
is trying to make. It is remarkable that Lomborg has been unable to
find any more authoritative source for this figure, and that the whole
story here is therefore extremely weakly founded. This, however, has
not prevented many other climate skeptics from repeating the story.
ERROR
Page 3: "Contrary to what you might expect . . . the two
populations in decline
come from areas where it has actually been getting colder over the past
fifty years. . "
Error:
The two areas referred to are the Baffin Bay and Davis Streat
areas, including the west coast of Greenland. Air temperatures in the
latter area have declined during the period 1950-1970, but have
increased gradually from 1970 onwards. That is, during the period when
the population sizes of polar bears have declined, air temperatures
have increased (see this link).
At
the
east
coast
of
Labrador,
rises in air temperatures have come
later, but they are clearly rising now (Przybylak (2000), cited by
Lomborg. What is crucial to the polar bears, is that the sea ice does
not
break up too early in the summer. Data from 1979 onwards for these
regions show that on
average, the data of ice breakup has become ever earlier, i.e. the
climate has become ever milder, contrary to what Lomborg says. This
evidence is presented clearly in the paper I. Stirling &
C.L.Parkinson (2006): Arctic 59: 261-275, which has been presented to
Lomborg. Climate trends before 1979 are irrelevant, because the trend
of the bear populations are not known so far back in time. Thus Lomborg
writes something which he knows is irrelevant (before 1979) or wrong
(after 1979), i.e. he misleads deliberately.
It may be added that polar bear populations have been
stable in the Southern Hudson Bay, where the climate has been slightly
cooling for some period.
(GROUNDLESS DEROGATION)
Page 3: "Contrary to what you might expect and not something that was
pointed out in
any of the recent stories, the two populations . . .
"
Comment:
Lomborg insinuates that "the recent stories" were not honest, omitting
evidence that decline concurs with a cooling climate. But as the
climate was actually warming, not cooling, during the periods when
polar bears declined, this insinuation is
groundless.
FLAW
Page 3: "Al Gore´s comment on drowning bears . . in one of
the increasing bear
populations."
Flaw:
The episode of four drowned bears was related to a situation
where many bears had already problems swimming in open water far
from the nearest ice or land. See this link. Specialists say in the recent report
(14th meeting) that "The primary concerns for this
subpopulation are from climate warming that continues to expand
both the expanse and duration of open water in summer and
fall." And the population is probably decreasing, not
increasing.
FLAW
Page 3 bottom, figure 1:
Flaw:
To construct this graph, Lomborg has combined data from two figures,
one from Stirling et al. (1999), the other from Amstrup et al.
(2006). The left part is taken from Stirling, the right part from
Amstrup. In the period of overlap (1985 to 1997) the two curves
do not agree fully. Unfortunately, in
the Stirling et al.paper the graph is presented without explanatory
comments. More
original data are in the following paper: A. E. Derocher & I.
Stirling (1995): Journal of wildlife management 59(2): 215-221. Here is
a curve covering the period 1978 to 1992. Again, the data here do not
agree fully with the two other curves. All three curves have error
bars. The approximate population size for 1985 is given in Derocher
& Stirling as 1,150 ± 600, in Stirling et al. (1999) as
1,500 ± 500, and in Amstrup et al. as 850 ± 300. Thus, a
value in the range 1,000 - 1,150 is compatible with all three data
sets. But Lomborg has chosen to use only the highest figure for that
year, and to leave out any error bars. Likewise, for the low point in
1981, he could just as well have presented an alternative figure of 800
± 400. Thus, the difference between 1981 and 1985 is not
significant. And indeed, the paper by Derocher & Stirling says (p.
220): "Poulation size did not show any trend between 1980 and 1992".
Having taught statistics,
Lomborg should have been able to understand that the trend is not
significant. But he
has chosen to neglect reservations pointed
out to him by experts in the field, and has draw his own false
conclusions. If
he had taken account of known facts on polar bear biology,
he would have known that isolated populations can grow by maximally 3-4
% per year, and that growth by immigration from neigbouring populations
is very limited. The population increase that Lomborg postulates
can impossibly have occurred.
So, the trend that Lomborg has stressed and
dramatized - the leap upwards from 500 to 1,500 - is just a statistical
artifact due to large uncertainties in the figures. Having taught
statistics,
Lomborg should have been able to understand that.
Unfortunately others,
including Rosing-Asvid, cited by Lomborg, have taken the
figures from Stirling et al. (1999) literally, without considering that
a rise from 500 to 1,500 is
impossible, and without considering the uncertainties involved . Over
a period of four years, a polar bear
population can maximally grow by about 15 %, i.e. there could have been
a rise from e.g. 1,000 to 1,150, but certainly not from 500 to
1,500.
It is believed that the population was exposed to
overhunting before hunting regulations in 1968, and it is believed
therefore that it increased especially from the late 1960s and well
into the 1970s. But the apparent increases that Lomborg refers to are
statistical artifacts.
FLAW
Page 3 bottom, note 26 to figure 1: "Stirling points out (personal
communication) that . .
Flaw:
What Stirling tried to explain to Lomborg is that there are large
uncertainties in population estimates based on capture-recapture data.
For a long-lived species like the polar bear, the uncertainties are
especially large when only capture data from a single year are utilised
for each point estimate. For instance, when a bear has been captured in
1984 and 1986, it must have been present in 1985 too, but this
information is lost when the 1985 population estimate is based only on
data from that particular year. There exist mathematical procedures by
which data from neighbouring years are also utilised (the Jolly-Seber
method); this method has not been used by Stirling, but he has handed
the data over to other scientists (Amstrup et al.) who have reanalysed
the data by utilising mulit-year data sets. This means that the
estimates arrived at by Amstrup et al. are more reliable than those
published by Stirling et al. In addition, the apparent increase during
the early 1980s is also explained by the fact that sample sizes and
area covered were increasing rapidly, that is, data for 1981 did not
cover the whole region, which of course means that the population
estimate is too low. If the first estimate (Derocher & Stirling
1995) included only captures from the core region, and later estimates
included a few additional captures made at the periphery of the region,
where the chance of recapture is low, then this would have the effect
to lower the recapture rate and thus boost the population estimate.
Thus, using data from the first years when the study area is extended
will cause population estimates to be unrealistically high, but
including data from subsequent years, when these bears are recaptured,
will tend to reduce the population estimates to more realistic levels.
Lomborg should know all this, as he has corresponded
with several scientists on the issue. He has probably not understood
the mathematical problems involved, but at least he has understood that
the low estimates for the early 1980s are biased to the low side. He
conceals this insight at the end of note 26 (and leaves it out
completely in the American version of the book), and on page 4 he
writes as if he did not know this.
Those readers who care to look up note 26, are met with
the following sentence: "Stirling et al. are coming out with a new data
set, but they would not share it . . . " At first sight, this may look
as if Stirling is an unkind person. Actually, he was the person who
sent the paper by Stirling et al. (1999) to Lomborg, and he urged a
colleague to write additional explanation to Lomborg, and to promise to
send an additional paper when this was published.
GROUNDLESS DEROGATION
Page 4, top: ". . the western coast of Hudson Bay. . . Not
mentioned, though, is that the population research . . "
Error:
As explained in relation to Figure 1 and to note 26, the data for the
early 1980s are so uncertain that the apparant trend for a population
increase is not significant. This is a good reason why scientists have
not focused on trends during this period. But Lomborg twists the
evidence to throw unjustified suspicion on the scientists. As he knows
that the trends for the early 1980s are too uncertain, this is a case
of deliberate unjustified
derogation.
ERROR
Page 4, top: ". . . Here, the
population has soared from just 500 in 1981 . . ."
Error:
As explained in relation to Figure 1, this is not true. There is no
statistically significant trend between 1981 and 1985. It should be
fundamental for a person who has taught statistics not to proclaim that
an important trend has been observed, without checking if the apparent
trend could possibly be due to statistical variation, which is
certainly the case here, because the postulated rise could impossibly
have occurred in the real world.
As Lomborg has corresponded with the scientists, he
knows all this. What he writes is deliberately
misleading.
FLAW
Page 4: "it means we have lost about 15 bears to global warming each
year, whereas we have lost 49 bears each year to hunting."
Flaw:
With this sentence, Lomborg either demonstrates a blatant lack of
understanding of ecology, or purports to lack this understanding.
In a stable population, it is possible to obtain a `sustainable
yield´, because the population each year produces a surplus of
young, some of which will die from natural causes if they are not
shot by man. Calculations are made by wildlife biologists to find
the size of the `sustainable yield´, i.e. how many bears may be
shot each year without causing the population to decline. Permits are
then issued to shoot this amount of bears, with the
local inuit population receiving most of the permits. However, if
conditions get worse, the bears produce less
young, and the sustainable yield decreases. That is, the
increased melting of sea ice means that the population tolerates
less hunting than before. So harvesting the sustainable yield does not
imply a lasting reduction of the population (a "loss"), whereas a
decline in
the size of the sustainable yield is indeed a loss, to the polar bear
population and to the people hunting them.
ERROR
Page 4: " In 2006, a polar bear biologist from the Canadian government
. ."
Error:
The biologist referred to is Mitchell Taylor. The quote may be seen in
full in this link.
He
does
not
work
for
the
Canadian federal government, but for the
government of the Nunavat territory, where local interests in allowing
large quotas for beer hunting probaly have a greater weight.
FLAW
Page 4: "we hear vastly exaggerated and emotional claims that
are
simply not supported by the data."
Flaw:
The claims are not exaggerated, and they are supported by the
data.
ERROR
Page 4 bottom and note 33: " Yes it is likely that disappearing ice
will make it
harder . . and that they more often will take up a lifestyle similar
to that of brown bears
. ."
Error:
In note 33, Lomborg writes: "The Arctic Climate Assessment finds it
likely that disappearing ice will make polar bears take up `a
terrestrial summe lifestyle similar to that of brown bears . .´
". But here follows the original text in the assessment report (Symon,
Arris and Heal 2005 p. 509; Berner is not among the editors): "It is
difficult to envisage the survival of polar bears as a species given a
zero summer sea-ice scenario. Their only option would be a terrestrial
summer lifestyle similar to that of brown bears, from which they
evolved. In such a case, competition, risk of hybridization with
brown bears and grizzly bears, and increased interactions with people
would then number among the threats to polar bears." Thus, in the cited
text, the eventual survival of polar bears on land is presented as a
hypothetical possibility, fraught with several difficulites. It is
certainly not presented as something "likely".
ERROR
Page 4 bottom: "But over the past forty years, the population has
increased
dramatically. . "
Error:
As stated above, this is not true.
FLAW
Page 4 bottom: ". . and the populations are now stable."
Flaw:
This might have been true up to 2001, but in 2005 it was no longer
true.
(COMMENT)
Page 4 - 5: "In general, the Arctic Climate Impact
Assessment projects that the Arctic will experience increasing species
richness . . . "
Comment:
Lomborg usually accuses biologists of focusing on negative trends and
ignoring positive trends. But the ACIA report presents in a neutral way
positive as well as negative trends. There is no obvious bias. But
Lomborg can always twist his text in such a way that we are left with
the impression of overly pessimistic environmentalists - also in this
case when they make a neutral contribution. On the other hand, Lomborg
himself is not neutral here. He only cites those parts of the text on
pages 997-998 that deal with positive trends, and ignores all text
dealing with various species that will probably decline or go extinct.
He ignores that species disappearing from the Arctic will disappear
completely from the globe, whereas species that will immigrate to the
Arctic already exist elsewhere - that is he ignores the risk that the
total number of species on the globe will decline.
(COMMENT)
Page 5 top: ". . the plight of the polar bears shows
"the
need for stricter curbs on greenhouse-gas emissions . . "
Comment:
The cited newspaper article did not exactly say so. The reason given in
the article for the need for curbs is rather that the polar bear are
indicators of climate change in the Arctic areas, and that these areas
provide a bellwether of what´s coming to the rest of planet Earth.
(GROUNDLESS DEROGATION)
Page 5 top: "Even if we accept the flawed idea of
starting to count bears at Hudson Bay at close to the maximum in 1987.
. ."
Flaw:
The idea is not flawed.The population around Hudson Bay did not have an
aberrant size in 1987.
The study of population trends starts with those years when data are
sufficiently certain.
FLAW
Page 5: "Thus, if we care for stable populations of polar
bears,
dealing first with the 49 shot ones might be both a smarter and a
more viable strategy."
Flaw:
This is nonsense due to Lomborg´s lack of understanding of the
concept of sustainable yield (as explained above). If we want a stable
population, we can shoot 49 bears annually without compromising the
stability. If the 49
bears were not shot, a similar number of bears would die from other
causes. On the other hand, when the environment becomes less
favourable, then the
sustainable
yield decreases, and the number of bears shot annually will have
to be reduced to avoid an acceleration of the ongoing decline.