Bjørn
Lomborg
versus Al Gore
|
|
List of acknowledged errors in Gore´s
book
and film |
|
Lomborg versus Gore |
SOURCES |
B = The book, "An Inconvenient Truth"
F = The film, "An Inconvenient Truth"
DVDs may be purchased from this official web site. A transcript of the film is found on this web site. The transcript is not absoluteley accurate and has a few errors (e.g. "The Errol Sea" instead of "The Aral Sea").
Sources of alleged errors are listed here.
Out
of many alleged errors, I have selected those that could be
acknowledged. In addition I list those points that need lengthy
comments.
The judgment at a British high court about 9 alleged `errors´
in Al Gore´s film is summarized here.
LIST OF ERRORS, FLAWS AND POINTS NEEDING EXTENSIVE COMMENTS |
(COMMENT)
F, B p42: "It is evident in the world around us that very dramatic
changes are taking place: This is Mount Kilimanjaro in 1970 with its
fabled snows and glaciers. Here it is just 30 years later - with far
less ice and snow."
Comment:
What causes the ice on top of
Kilimanjaro to disappear, is a complicated issue. A review of the facts
and arguments is presented on this
page in
Lomborg-errors.
The disappearance of the ice could be due
to two possible causes, or any combination of the two. One possibility
is that ice disappears due to melting because of rising temperatures.
This is favoured by the study group around Lonnie Thompson. The other
possibility is that ice disappears only by sublimation, not by
melting, and that it disappears because of reduced snowfall, so that
the ice surface is less white and absorbs more of the sun´s
radiation. This is favoured by the study group around Georg Kaser.
It is not settled what explanation is most correct, which means that it
can
not
be
said for certain that the disappearance of the ice cap is due to global
warming, and it can not be said for certain that it is not due to
global warming.
Al Gore´s presentation is obviously based on information from
Lonnie Thompson. This information is that the ice cap has existed for
thousands of years, but is disappearing only now. There is considerable
melting on the horizontal surfaces, melting that has not happened
before. Precipitation has been low also in previous periods, when the
ice cap persisted, but seems to have increased in recent years, when
the ice cap is disappearing. Based on these facts, it is understandable
that Al Gore can conclude that the cause of disappearance is global
warming. As the issue is not settled, we cannot say definitely that
Gore is wrong. This is therefore not counted as a flaw. But it is
unfortunate that to demonstrate global warming, Al Gore has chosen just
Kilimanjaro,
where
the cause of the disappearance of the ice cap is not known for
sure. In practically all other glaciers, their
disappearance is partially due to rising temperatures, and partially
due to changes in precipitation. For some tropical glaciers, changes in
temperature have little influence, but for many tropical glaciers (the
majority of which are found in South America), temperature has
considerable influence on their gradual disappearance (link).
As
by far the majority of all glaciers worldwide are receding, it is
obvious that global warming is a major cause. Although such recession
has been underway since around 1850, the rate of glacier recession has
been accelerating recently. During the years 1961-1990,
melt water from glaciers and ice caps around the world, excluding
Greenland and Antarctica, contributed a total of 0.33 mm per year to
global sea level rise. For the years 2001-2004, the contribution was
0.77 mm per year, that is, more than twice (reference: this
link). So the point that Al Gore tries to make is correct, but
Kilimanjaro is one of the worst examples he could have chosen.
FLAW
B p48: The book shows a large photo from 2003 of the Perito Moreno
glacier in Argentina. The text above the picture is "Almost all of the
mountain glaciers in the world are now melting, many of them quite
rapidly. There is a mesage in this."
Flaw:
Perito Moreno is a bad example. Nearly all glaciers in Patagonia are
receding. A survey of 95 glaciers in the Chilean part (link)
showed that 6 % were advancing, 6 % were stable, and 88 % were
receding. According to the wikipedia article,
Perito
Moreno is one of only three Patagonian glaciers where the front
is not
retreating. According to this paper,
the
Moreno glacier is the only glacier in Patagonia where the ice sheet
is not thinning. It is therefore unlucky that Gore chose to use just
this
glacier to illustrate his point. Although he does not directly state
that the glacier in the photo is receding or thinning, this is
nevertheless counted
as a flaw. In the film the scene is shown while Gore says: "And it is a
shame because these glaciers are so beautiful", so one might argue that
the scene is just used to illustrate the beauty that should be
preserved. However, the judgement I make here is that because of the
context in which this glacier is shown, people may be misled.
FLAW
F: "In the Himalayas . . . people get their drinking water from
rivers and spring systems that are fed more than half by the melt water
coming off the glaciers."
(B p58): "The Himalayas . . . provide more than half of the drinking
water
for 40 % of the world´s population."
Flaw:
That part of the river flow that originates from glaciers is much less
than half - it is rather 5 %. More information on the subject may be
read in a report on glacier
retreat
in Nepal, India and China, published by the WWF. According
to this report, out of the catchment area in the Himalaya
and Karakorum mountain areas, about 20 % is covered by permanent
glaciers, and an additional c. 40 % has seasonal snow cover. Out of the
Tibetan plateau, about 4 % is covered by permanent glaciers. Most of
the water in the large rivers, such as Indus and Ganga-Brahmaputra,
originates from monsoon rain. Meltwater from ice and snow fields
contributes only to 5 % of the annual flow of these rivers on a yearly
basis, but is crucial because it supplies water in the otherwise dry
seasons. So the rivers are not "fed" more than half by melt water
from these areas.
In the book, the wording is different. Here it is
evident what Al Gore meant, namely that more than half of the river
flow originates from the mountain areas (he incorrectly writes as if
the Himalayas are the same as the Tibetan Plateau). Apparently, he
assumes that the mountain areas are totally covered by glaciers, but he
does not write that in the book, so the flaw is only in the film.
Al Gore is right in his main point, namely that
people
dependent on these rivers are going to face water shortage within the
next half century partially because of disappearance of ice and snow.
The projected changes, according to the WWF report, are that in the
upper Indus,
there will be initial increases of water flow ranging from +14 to +90 %
over the first few decades when the glaciers melt, followed by
decreases of -30 to -90 % after
100 years. For the upper part of the Ganga, the change will be +20 to
+33 % during the first two decades, and after that a decrease by -50 %.
For the lower Ganga, there will be little change. For the Brahmaputra,
there will be a drecrease of water flow throughout.
FLAW
F: "They can go back in a lot of these mountain glaciers a thousand
years. They constructed a thermometer of the temperature."
B p63: "The thermometer to the right measures temperatures in the
Northern Hemisphere over the past 1,000 years."
p64: "But as Dr. Thompson´s thermometer shows,
the vaunted Medieval Warm Period (the little red blip form the left,
below) was tiny . . "
Flaw:
In Al Gore´s presentation, the audience will understand that the
"thermometer" for the last 1,000 years originates from measurements of
oxygen isotopes in ice cores drilled by mr. Thompson´s team.
However, a confusing detail is that the graph on p. 63 shows
temperatures for the Northern Hemisphere, and half of Thompson´s
glaciers are from the Southern Hemisphere. What has happened is that Al
Gore has used the graph in Figure 7.d in the paper
on Thompson´s glaciers, and this graph does not show
Thompson´s own data, but - for comaprison - the "hockey stick" of
Mann et al. (1999). So what is presented here is only the well-known
fact that Mann´s hockey stick shows very little warming during
the medieval age.
(COMMENT)
F, B p67:
Commenting on the fit between graphs of past CO2 and past temperature:
" The relationship is very complicated. But . . when there is more
carbon dioxide, the temperature gets warmer."
Comment:
According to Gore´s opponents, his presentation imparts the
conception to his audience that the observed increases in temperature
are the result of increasing
CO2. Gore conceals the important detail that the CO2
signals mostly lag nearly 1,000 years behind the temperature signals.
This
detail points to the conception that the relationship is rather the
other way around: increasing CO2 is the result of increasing
temperature. However, both conceptions are too simplistic. Reality is
that the effect goes both ways. This is explained on the Lomborg-errors
page on the CO2 lag.
It is apparent that the full explanation of what
happens when temperatures and atmospheric CO2 change is
very complicated. Al Gore could not possibly explain this in a popular
movie. Instead he just says "the
relationship is very complicated". He then jumps directly to that part
which is important in the present context, viz. that more CO2 causes
higher temperatures - which is correct. It would have been more correct
if Gore had said that probably about half of the temperature change was
caused by changes in greenhouse gases. But formally, the formulation
"when there is more
carbon dioxide, the temperature gets warmer" is correct, and it is also
central to his theme, because he wants to conclude from the past to the
future, and the message is that more CO2 will cause
higher temperatures in the future. IPCC presents an estimate (wgI
report, FAQ 2.1) that the present high level of CO2
gives a climate forcing of 1.7 watt/m², which is obviously large
relative to the forcing of 0.7 watt/m² that is caused by changes
in the Earth´s orbit.
(COMMENT)
F: About the atmospheric CO2 level: ". . here´s
where it´s going to be in the next fifty years - really, in
less than fifty years."
B p67:
"And within 45 years, this is where the CO2 equivalent
levels will be if we do not make dramatic changes quickly."
Comment:
In the book as well as in the film, Gore´s presentation is
confusing, especially because he uses a distorted vertical axis. In the
book, there is one scale from 200 to 300 ppm, and another (more
condensed) scale from 300 to above 600 ppm. This means that the
projected value for 2050 appears not as high above present as it should
if the scale were uniform. On the other hand, the future value is shown
at 620 ppm. This is higher than projected by the IPCC for CO2,
but
the text says that this is the value for CO2
equivalents, which includes CH4, and therefore the
figure is correct. So there are two distortions: one
is the condensed scale which few will notice, and which
tends to belittle the trend; the other is the shift from CO2
to CO2 equivalents which few will notice, and which
tends to magnify the trend. All in all, the presentation is formally
correct and the graph does not exaggerate the rising trend.
In the film, there is no mentioning of "CO2
equivalents". It is practically impossible to read the units on the
vertical scale, and if one tries to extrapolate where the point for
2050 lies, considering that zero on the vertical scale is not at the
bottom line, one reaches a value of about 500 ppm, which coincidentally
fits well with the value projected by the IPCC.
Thus, in the film too there is no graphic
exaggeration of the rising trend.
FLAW
(COMMENT)
F, B p 94: "And then of course came Katrina. . . And then when it comes
into
the Gulf over that warm water it picks up that energy and gets stronger
and stronger and stronger. . ."
Comment:
Al Gore does not postulate that Katrina was caused directly by global
warming. His argumentation is that when oceans become warmer in
general, the hurricanes get stronger in general. That is, the risk of
having a severe hurricane increases, but you cannot speak of direct
cause and effect. Al Gore does suggest that the warm water in the
Mexican Gulf at that particular occasion did contribute to making
Katrina grow as strong as it did. This seems quite plausible. It has
been suggested that the high surface temperatures in the Gulf at that
occasion did extend unusually far down into deeper water layers, and
the amount of heat mobilised when deeper water was sucked up into the
cyclone made it possible for the hurricane to grow exceptionally
strong. The risk that the deeper water would have been so warm is
obviously larger when we have global warming.
Therefore, it seems that there is no flaw in Al
Gore´s
argumentation here and that the judgment made by the high court in
London on this particular point (read here) is not warranted.
FLAW
F: "The insurance industry has actually noticed this. They´ve
recorded losses are going up. You see the damage from these severe
weather events."
B p102: "The insurance industry is one business sector that´s
already feeling the unmistakable economic impact of global warming. . .
As one business leader put it, insurance companies face "a perfect
storm of rising weather losses, rising global temperatures, and more
Americans than ever living in harm´s way."
Flaw:
The increasing economic losses reflect mainly that more and more
property is subject to damage, and more and more people live in high
risk coastal zones. The are not "unmistakable". When the trends
are adjusted for these changes,
there remains no long-term trend during the 20th century. This is
explained e.g. by Lomborg in "Cool it!". Therefore, although
Gore´s presentation is not formally wrong, it is nevertheless
misleading. The small reservation "more Americans living in
harm´s way" is not enough to prevent this from being counted as a
flaw.
FLAW
B p106: " . . the number of large flood events has increased decade by
decade, on every continent." Illustration titled: "Number of major
flood events by continent and decade."
Flaw:
The chart illustrating the rise in flood events is taken from page
448 of the Millenium Ecosystem Assessment report, Eco-Systems and Human
Well-Being. The graphic presentation has been changed, but it is
an approximately correct reproduction of the information, except that
the original chart was labelled "Number of recorded flood events by
continent and decade in twentieth century", whereas Gore´s
book has the wording "Number of major
flood events". Now, the word `major´ might suggest
something about the physical magnitude of meteorological events,
but that suggestion is spurious, as pointed out in the CEI criticism of the book.
Actually, the chart presents the data from the EM-DAT global
disaster database at the university at Louvein in Belgium . As
explained on page 447 of the Millenium Ecosystem Assessment
report, only events that are classified as disasters are reported in
this database. An event is declared as a disaster if it meets at
least one of the following criteria: 10 or more people are reported
killed; 100 or more people reported affected; international assistance
was called; or a state of emergency was declared. The
rising trend from 1940 onwards may partially be due
to increased reporting of actual events, and partially to changes in
socioecoomic systems, such as growth of cities along rivers (which is
stated in the report). In addition, it is obvious that with
increasing population sizes, the risk that at least 100 people will be
affected by a flood of a given size is greatly increased. Gore
does not mention these caveats.
All in all, there is little or no indication
that the average frequency or physical magnitude of floods has
actually increased during the 20eth century.
IPCC states (FAR wg2, chapter 1) that there is
no evidence for at climate-related trend in floods. Increasing damages
have been due to increasing vulnerabilities.
Therefore, the graph presented by Gore is so misleading that it will
count here as a flaw.
See also the comments to the incidence of wild
fires (p. 229 in Gore´s book).
(COMMENT)
F:
". . Lake Chad, once one of the largest lakes in the world. It has
dried up over the last few decades to almost nothing."
B p117: "But now, due to declining rainfall and ever-intensifying human
use, it has shrunk to one-twentieth its original size."
Comment:
The drying up of lake Chad (shrinking from 25,000 km² in 1963 to
1,350 km² recently) is most probably caused by several factors
working in concert. Overgrazing reduces the vegetation cover, and the
reduced vegetation cover means less evaporation of water and hence less
precipitation of condensed water vapours. With less and less
precipitation, human and animal populations have come to rely more and
more on water from
the lake. Massive irrigation projects to combat the drier climate
diverted water from both the lake and the two main rivers that empty
into it, the Chari and the Logone. In addition to these effects, there
has also been a climate change, i.e. reduced rainfall, in the region
during the latter half of
the 20th century. Anada Tiega of the Lake
Chad Basin Commission blames climate change for 50 to 75 percent of the
water's disappearance (link).
According to a study of Hoerling
et al. (2006), the change in rainfall is related to higher sea
surface temperatures in the southern Atlantic relative to the northern
Atlantic. In that study, this difference between the southern and the
northern Atlantic is most probably not a consequence of global warming.
But other sources state that the reduced rainfall can be simulated by
computer models
that incorporate an increasing greenhouse effect, see here or in the IPCC
wgI report, FAQ 3.2. This means that
the drying of the region during the latter half of the 20th century is
part of a global climate
variation, but it is uncertain if it is connected to global warming.
Global warming may or may not in the future lead to more warming of the
southern than the northern Atlantic. The El Nino phenomenon also has
some role to play in this, and unfortunately existing computer programs
cannot model the El Nino phenomenon.
Does Al Gore properly represent this state of
information? The
voice in the film
says: ""And focus most of all on this part of Africa, just on the edge
of the Sahara. Unbelievable tragedies have been unfolding there, and
there are a lot of reasons for it. But Darfur and Niger are among those
tragedies. And one of the factors that has been compounding them is the
lack of rainfall and the increasing drought. This is Lake Chad, once
one of the largest lakes in the world. It has dried up over the last
few decades to almost nothing, vastly complicating the other problems
that they also have." It is apparent here that Al Gore pays due regard
to
the multifactorial character of the problems, and does not directly
postulate
that any particular phenomenon is due to global warming.
In the book, he clearly states that the drying up is due both to
declining rainfall and to intensifying human use. This too, is a
balanced
presentation. Although the example is presented in a context of global
warming, it is not said that global warming caused the problem.
Therefore, it seems that the judgment made by the high
court in London
on this particular point (read
here) is not warranted.
FLAW
F: About ice cores from Antarctica: " . . right here is where the US
Congress passed the Clean Air Act . . you could see the difference with
your naked eye."
B p139: "Yet another surprise for me was when scientists showed me that
near the South Pole, the presence of air pollution in the ice cores
visibly declined not long after passage of the US Clean Air Act in 1990
. . you can actually see the before and after with your own eyes."
Flaw:
Changing atmospheric pollution on the Northern Hemisphere would leave
no signs on Antarctica. According to IPCC, 4AR wg1 paragraph 6.6.3.3.,
"Data from ice cores show that sulphate aerosol deposition has not
changed on Antarctica, remote from anthropogenic sulphur dioxide
sources". See also this page on
Realclimate. To cite Bob
Edelman: "I will give Gore the benefit of the doubt and say that he
was the victim of a joke." But, joke or not, you may say that the
public is being misled.
FLAW
(F):
". . for the first time they are finding polar bears that have actually
drowned, swimming long distances up to 60 miles to find the ice."
B p146: "A new scientific study shows that, for the first time, polar
bears have been drowning in significant numbers. Such deaths have been
rare in the past."
Flaw:
The presentation in the film is OK, but the book has the wording "in
significant numbers", which is hardly correct.
There are limits to how far polar bears can swim in
open water. When
the sea ice melts away faster than usually, and the bears roaming there
need to head for firm land, they may have to swim longer distances than
before. In September 2005 an unusually high number of bears were found
swimming in the Beaufort Sea north of Alaska. Just then came a storm,
and after the storm scientists observed the carcases of 4 drowned
bears. This has not been observed before (and not since then).
See more details in this link.
The crucial point is that the bears are forced to
swim longer distances than before, and therefore are at a greater risk
if a storm comes. When Gore presents this episode as something that
will happen more frequently in the future, he may be wrong, but most
likely he is right. Therefore, it seems that the judgment made by the
high court in London
on this particular point in the film (read
here) is not warranted.
On the other hand, the book says "in significant
numbers". Four bears in one single episode is hardly significant in any
way, and this is therefore counted as a flaw.
(COMMENT)
F: "Is there any other big chunk of ice near
there? [referring to Greenland] Oh Yeah! "
B p 149: "10,000 years ago . . . the Gulf Stream virtually
stopped. . . Consequently, Europe went back into an ice age for another
900 to 1,000 years . . . Some scientists are now seriously worried
about the possibility of this phenomenon recurring."
"Dr. Ruth Curry is especially concerned about the rapid melting of ice
in Greenland . . Recently, she observed: `The possibility of such
extreme events precludes ruling out that disruption of the North
Atlantic conveyor in the 21st century could occur as a result of
greenhouse warming.´"
Comment:
What IPCC says about this, is as follows (wgI report, section
10.3.4
and FAQ 10.1). They speak of the "Atlantic Meridional Overturning
Circulation (abbreviated MOC; also referred to as the thermohaline
circulation) and write: "Taken together, it is very
likely that the MOC . . will decrease . . but very unlikely that that
the MOC will undergo an abrupt transition during the course of the 21st
century." And they write further that most models agree that the amount
of water circulated by the MOC will decrease by somewhere between an
insignificant amount and 50 % by 2100. No model shows an abrupt change
before 2100, but some long-term model simulations suggest that a
complete cessation can result for large forcings. Thus, an abrupt
change after 2100 cannot be excluded. The changes will not completely
prevent that the warming of Europe continues.
Does Al Gore´s presentation agree with the
scientific consensus as expressed by the IPCC? The phrasing in his book
that "some scientists are seriously worried" can hardly be denied,
provided that by "this phenomenon recurring" we refer to the halt of
the Gulf Stream, not Europe going back into an ice age. Concerning the
film, Al Gore is ironic and very unprecise. He says: "Of course
that´s not gonna happen again because the glaciers of North
America are not there and . . Is there any other big chunk of ice near
there? [referring to Greenland] Oh Yeah! We´ll come back to that
one." So he indirectly suggests that melting of the Greenland ice could
do more or less the same to the termohaline circulation once more, but
he gives no
clue to the likelihood or extent of such a scenario. He does not
suggest a complete repetition of the scenario from 10,000 years ago.
Thus, formally there is nothing wrong in his presentation.
(COMMENT)
B p 149: "10,000 years ago . . . the Gulf Stream virtually
stopped. . . Consequently, Europe went back into an ice age for another
900 to 1,000 years . . . Some scientists are now seriously worried
about the possibility of this phenomenon recurring."
Comment:
Gore writes about an episode in the past when the Gulf Stream stopped,
and writes that this might recur. There has been some criticism that he
writes `Gulf Stream´ when what would actually stop would be the
thermohaline circulation. This is important, critics say, because the
Gulf Stream is driven by wind, whereas the thermohaline circulation is
driven by differences in sea temperatures and salinity. They claim that
if the thermohaline circulation stopped, the Gulf Stream would not
stop, and cooling of Europe would probably not happen. This criticism
is partially a dispute over words; the common understanding
of the Gulf Stream, especially in Europe, is that it includes the
extension of this stream towards Europe, an extension called `the North
Atlantic Drift´. This drift is mainly driven by the thermohaline
circulation. If that stopped, that wind-driven part of the Gulf Stream
would bend off and not continue northwards, which means that the
northern half of Europe would indeed become cooler. In a film and book
like this, some popularization is
unavoidable, and also for this reason the conflation of the two systems
is acceptable.
(COMMENT)
B p 150: "Dr. Ruth Curry is especially concerned about the rapid
melting of ice
in Greenland . . Recently, she observed: `The possibility of such
extreme events precludes ruling out that disruption of the North
Atlantic conveyor in the 21st century could occur as a result of
greenhouse warming.´"
Comment:
The quote from Ruth Curry could not be found on the internet. There
were other quotes to be found which are generally less scaring and some
of which explicitly state that Europe will not cool. As Gore does not
give the source of the quote, it is not known if it is correct. In an
email (10 Jan 2008) Ruth Curry writes: "I don´t remember if I
used the word "disruption". But if I did, it was in the context of a
slowing of the heat-bearing currents flowing northward of
Iceland-Scotland, not a complete stoppage of flow." She further writes
that at the time that the Gore team was assembling the scientific
evidence presented in "An Inconvenient Truth", there was genuine and
justifiable concern over what was being observed in the North Atlantic.
But the 30-year trend of freshening in the northern North Atlantic
reversed around the year 2000, and looking back it is now clear that
the freshening did not have a sustained impact on the Ocean Conveyor.
(COMMENT)
F: "Coral reefs all over the world because of global warming and
other factors are bleaching . . All the fish species that depend
on the coral reef are also in jeopardy as a result."
B p 166: "The link between global warming and the large-scale bleaching
of corals, considered controversial only 10 to 15 years ago, is now
universally accepted."
Comment:
The bleaching of corals is treated by IPCC in the 4AR wg2 report,
in several paragraphs. Paragraph 1.3.4 says: "There is now extensive
evidence of a link between bleaching . . and sea surface temperature
anomalies." and "In 1998, the largest bleaching event to date is
estimated to have killed 16% of the world´s corals . . On many
reefs this mortality has led to a loss of structural complexity and
shifts in reef fish species composition . . ". Paragraph 6.2.5 and box
6.1 say: "Global warming poses a
threat to coral reefs, particularly any increase in sea surface
temperature. The synergistic effects of various other pressures,
particularly human impacts such as over-fishing, appear to be
exacerbating the thermal stress on reef systems and, at least on a
local scale, exceeding the thresholds beyond which coral is replaced by
other organisms." "Coral bleaching, due to loss of symbiotic algae
and/or their pigments, has been observed on many reefs since the early
1980s. . . If bleaching is prolonged, or if sea surface temperature
exceeds 2°C above average seasonal maxima, corals die. . . Recent
preliminary studies lend some support to the adaptive bleaching
hypothesis, indicating that the coral host may be able to adapt or
acclimatise as a result of expelling one clade of symbiotic algae but
recovering with a new one . . . Corals and other calcifying organisms .
. remain extremely susceptible to increases in sea surface temperature."
It appears that Al Gore´s presentation is
fully in accordance with the general scientific view as expressed in
the IPCC report. Therefore, it is strange that the judgment made by the
high court in
London (read here) does
not fully reject objections to this point. The judge states: "The
actual scientific view, as recorded in the IPCC report, is that, if the
temperature were to rise by 1-3 degrees Centigrade, there would be
increased coral bleaching and widespread coral mortality, unless corals
could adopt or acclimatise . . ". That is, in the judge´s
opinion, coral bleaching is something that might possibly happen in the
future if sea temperatures rise, but not something that is already a
severe problem. It thus seems that the judge has been very much misled,
and that his statement is not warranted.
Actual dying-off of corals is by now well
documented. In Wilkinson (2004): Status of coral reefs of the world (link),
it
is said that 16 % of the world´s reefs were seriously damaged
in 1998, but that 6,4 % are recovering, leaving 10 % permanently dead.
It is also said that "The coral bleaching in 1998 was a 1 in a
1000-year event in many regions with no past history of such damage.
Also very old corals around 1000 years old died during 1998. Increasing
sea surface temperatures and CO2 concentrations provide
clear evidence of global climate change in the tropics, and current
predictions are that the extreme events of 1998 will become more common
in the next 50 years." It should be added that we are not just talking
about singular events. There is, in addition, a gradual decline.
Wilkinson (2004) shows a chart that the coverage of coral reefs in the
Caribbean
declined from 54 % cover in 1976 to 9 % cover in 2001. Thus on a longer
time scale, there is a very severe decline. In the light of this, Al
Gore has not exaggerated the severity of the situation.
FLAW
F: "There are cities that were founded because they were just above the
mosquito line. Nairobi is one. Harare is another. There are plenty of
others. Now the mosquitoes with
warming are climbing to higher altitudes."
B p173: " . . the mosquito line, which used to mark the altitude above
which mosquitoes would not venture." "Before 1970: cold temperatures
caused freezing at high elevations, and limited mosquitoes and
mosquito-borne diseases to low altitudes."
Flaw:
If the `mosquito line´ is understood as a line above which there
are no mosquitoes, then both presentations (film and book) are clearly
wrong. Nairobi was not founded with regard to the distribution of
mosquitoes, and was not free from malaria. However, the distribution of
malaria in time and space is a complicated issue whcih is discussed
more thoroughly on this page in
Lomborg-errors. It appears from this
that after
1970, malaria has become gradually more frequent in the Kenyan
highlands, and a series of severe
epeidemics occurred during the 1990s. Slight temperature increases
since 1987 may have contributed to the latter, but the rise just after
1970 is more likely due to other causes, with no contribution from
climate. In general, however, it is true that the incidence of malaria
decreases with altitude, and that there are increases in incidence
which may be explained by increases in temperatures in the most crucial
months. Thus, because the main point in Gore´s presentation is
probably correct and only the details are wrong, this is counted only
as a flaw.
ERROR
F, B p174: "We´ve had 30 so-called new diseases that have emerged
in
just the last quarter century." Diseases referred to in the book and/or
the film are Dengue fever, Lyme disease, West Nile virus, arenavirus,
Machupo virus,
avian flu,
Ebola virus, Marburg hermorrhagic fever, E. Coli 0157:H7, Hantavirus,
Legionella, Leptospirosis,
multi-drug-resistant TB, Nipah virus, SARS and Vibrio Cholerae 0139.
Error:
Gore gives the impression that the emergence of these diseases is
related to global warming. In the book on page 173 he writes: "Global
warming pushes all of these boundaries in the wrong direction, thereby
increasing human vulnerability to new and unfamiliar diseases." It is
true that warmer climates may promote the spread of certain infectious
diseases, especially malaria and dengue fever. For instance, as
explained in the Lomborg-errors page on
malaria in Kenya, even a slight increase in temperature may
markedly increase the infection rate of the malaria parasite, or change
conditions from periodic infections to permanent infections. It is also
true that climatic change or unusual climatic conditions may give some
contribution to the greater spread of leptospirosis and hantavirus
pulmonary syndrome (link),
in
addition to lyme disease, legionnaires´ disease, Vibrio
cholerae 0139 and possibly West Nile virus. But concerning ebola, arena
virus, SARS, E. coli 0157:H7, avian flu, Nipah virus and multiresistant
tuberculosis, the contribution of climate change to their spreading
seems to be close to nil. To indicate that these diseases will spread
because of global warming seems to be scare tactics and has so little
to do with confirmed evidence that it is here counted as an error.
FLAW
F, B p175: "One example is the West Nile Virus, which entered the
United States on the eastern shore of Maryland in 1999. " "Two years
later, it was across the Mississippi. And two years after that it had
spread across the continent. These are very troubling times."
Flaw:
The West Nile Virus probably arrived in the United States via an
aircraft. The chance that it could get foothold may have been increased
a little by global warming leading to slightly more favourable
conditions for the virus in Maryland. However, once the virus had
become established, it was able to spread all over the US, in widely
different climates. An organism may require more optimal conditions for
getting a new foothold than for spreading from a core area. So it is
theoretically possible that it would not so easily have become
established with lower temperatures. But as there is practically no
concrete evidence for such a possibility, this is counted as a flaw.
(COMMENT)
F, B p183:
"Scientists thought that the
Larsen-B ice shelf would be stable for another century - even with
global warming."
Comment: Critics pose that the breakup of
ice shelves is not due to
man-made global warming, because these ice shelves have disappeared
before. This criticism is unjustified. The Larsen-B ice shelf has
existed without interruption since the ice age (Domack
et
al. 2005, Curry
&
Pudsey 2007), and its breakup is ascribed to man-made global
warming (Marshall
et al 2006). Also the IPCC report (4AR wg1 paragraph 4.6.3.4) says:
" . . the ice
shelf changes have resulted from environmental warming . . "" Before
the 2002 breakup of the Larsen B Ice Shelf, local air temperatures had
increased by more than 1.5°C over the previous 50 years ..
increasing . . formation of large melt ponds on the ice shelf. These
likely contributed to breakup . . ". Gore´s argument that the
breakup was unexpected is that the effect of these melt ponds had not
been understood previously. It may be added that air temperatures in
the Antarctic Peninsula region have risen by over 2.5°C in the last
50 years.
ERROR
F: "That is why the citizens of these Pacific nations have all had
to evacuate to New Zealand."
B p186: (showing a photo from one of the Tuvalu islands) "Many
residents of low-lying Pacific nations have already had to evacuate
their homes because of rising seas."
Error:
The wording in the film would imply that at least several Pacific
nations were by now completely evacuated, with no people left. This is
obviously far from the truth. The wording in the book would imply that
many had already evacuated. This is hardly so. There are serious
threats to a number of islands in the nations of Tuvalu, Kiribati
and the Marshall Islands, and two uninhabited islands in Kiribati
have disappeared (link).
In
2001, New Zealand made an (informal?) agreement to take 75 Tuvaluans
a year as part of its Pacific Access Category, and many Tuvaluans have
emigrated to New Zealand or Australia, for various reasons - in some
cases for fear of rising sea levels (links here, here
and here).
Up
to now, the movements have had the character of voluntary emigration
rather than forced evacuation.
Whereas global sea levels are rising as a general
trend, the sea surface is not absolutely stable and horizontal, and
there are areas where sea level rise has not yet occurred. The sea at
Tuvalu is one of the places where sea level has not risen recently.
Therefore, there is no new emergency situation up to now.
All in all, Al Gore´s presentation is not 100
% wrong, but it is dramatized to such an extent that it is counted here
as a full error.
(COMMENT)
F, B p189: Gore presents a graph showing
that annual closures of the Thames barriers increased in recent years.
Comment:
Critics claim that the more frequent closures have nothing to
do with rising sea levels; they claim the reason is a change of policy
by which the barrier is closed during exceptionally low tides, so as to
retain water in the tidal Thames rather than keeping it out. The
critics are completely wrong, however. For instance, one of the
statements on the official Thames Web
says as follows: ""Today's closure sets a landmark for the number of
times the Barrier
has closed to protect London from flooding and serves as a stark
reminder that living in the floodplain is never without risk. The rise
of sea levels is a reality, and although we are closing the Barrier at
the forecast rate, we expect closures to happen more frequently with 30
closures a year being the norm in 2030 if we don't make changes to the
current system."
(COMMENT)
F, B p190: " . . air temperatures high above the ice have warmed more
rapidly than
air temperatures anywhere else in the world."
Comment:
Gore correctly cites a study by Turner
(2006). The critics stress some uncertainties, e.g. that some model
runs do not replicate the observed tropospheric warming over
Antarctica, but it should be remembered that there are other model runs
that do replicate observations. In any case, actual observations are
more important than model projections. It is also worth remembering
that critics over and over again claim that whereas models predict more
warming in the troposphere than at the surface, such warming has not
been observed. Now, here is a case where we do have (much) more warming
in the troposphere than at the surface, and what do the critics say?
The say that this isn´t warming at the surface, so it
doesn´t count! In any case, melting of all that ice on Antarctica
takes heat out of the air, so maybe it is no wonder that air
temperatures
there rise very little.
(COMMENT)
F, B p196:
"IF Greenland broke up and melted, or if half of Greenland and half of
West Antarctica broke up and melted, this is what would happen to the
sea level . . ." "sea levels worldwide would increase by between 18 and
20 feet."
Comment:
Formally, Al Gore´s statement is correct. IF that amount of ice
melted, sea levels would rise by the indicated amount. In the film, the
word IF is pronounced with emphasis. So we are talking of a
hypothetical scenario. Gore makes no indication as to when this could
possibly happen; there is no clue indicating that it should be in the
near future. On various skeptics websites it is postulated that Gore
suggests that this would happen before 2100. This postulate is
completely unwarranted. He does not suggest that.
A good reason for Gore to be vague here is that it
is uncertain how fast these ice masses will melt in case of continued
unabated rise in CO2 levels. A plausible estimate is
that about half of the ice of Greenland would have melted away in a
thousand years from now. If also half of the West Antarctic ice mass
would melt, Gore´s scenario could be true at around the year
3000. But it might also happen faster. New evidence since data were
gathered for the latest IPCC report is that melting of sea ice
and land
ice in the Arctic is proceeding somewhat faster than anticipated.
Summer sea ice on the North Pole might disappear much earlier than
previously anticipated; this will increase the albedo, which is very
important for the acceleration of the warming. So the conception that
the 6 m rise in sea level might come earlier than in 3000 is not
completely unfounded.
Another objection to the plausibility of
Gore´s 6 m sea level rise is that much of the land ice on
Greenland remained in place during the previous interglacials, even
though temperatures then reached higher levels than now. But
Gore´s point is that the present situation is unprecedented -
there have never during the preceding interglacials been CO2
levels approaching the high levels to be expected already during the
21st century. So we do not expect a simple repetition of what happened
during the previous interglacials.
The scenes showing flooding of densely populated
areas might be called scare tactics, but I believe the audience will
generally understand that these scenes are hypothetical.
For these reasons, the attitude taken here is that
Gore´s presentation on this point is OK.
(COMMENT)
B p229:
"The graph below shows the steady increase in major wildfires in North
and South America over the last five decades; the same pattern is found
on every continent as well."
Comment:
Just the like graph on changes in flood events (see above for p. 106 in
Gore´s book), the graph on changes in fire events is taken form
the Millenium Ecosystem
Assessment report (page
449) and based on the EM-DAT global disaster database at the
university at Louvein in
Belgium. Gore´s presentation shows only the increase in the
Americas, which is the most dramatic, whereas increases in other
continents are more moderate. The chart in the original report is
designated "Number of reported wild fires by continent and decade in
the twentieth century". This has been relabelled "number of major
wildfires" in Gore´s book. Contrary to what is stated in the CEI criticism
of Gore´s book, this relabelling is justified, as the original
report does use the term "major fire events" in its text. It is
explained in the text that although the area burnt in USA has declined by
90 % from 1930 to now, the average annual number of major fires increased
markedly to about 10 in the 1980s and about 45 in the 1990s. A large
part of the explanation for this discrepancy is that when efforts to
suppress fires succeed on a short term, the amount of wood that
potentially could burn increases (the fuel load), and this increases
the likelihood that when a fire finally breaks out, it will be
catastrophic. The trend for more fires on average in Europe (except
Sweden and maybe other northern countries) seems to be real. In Europe
as a whole, the total extent and the interannual variability of the
area of burnt forest are higher for the period 1975-2000 than for the
1960s. This statistic involves physical measures rather than damage to
human values, and therefore the rising trend seems to be real.
Al Gore has taken data on floods and wildfires from
the same report, and treated them in the same way. For floods, the
result is misleading. For fires, it is not.
FLAW
B p252: (On emissions trading) "The European Union has adopted this US
innovation and is making it work effectively."
Flaw: Although the trade
with emissions functions, it has had no effect on CO2
emissions on a European scale up to now. The sum of the permits handed
out is larger than the sum of actual emissions. This situation is
hardly described by the wording "making it work effectively."
(COMMENT)
F:
"They took a big sample - 10 percent - 928 articles . . the number of
those that disagreed with the scientific consensus . . zero!"
B p262: "Naomi Oreskes . . . She and her team selected a large random
sample of 928 articles representing almost 10 % of the total . . "
Comment:
The
Oreskes article is summarized correctly. However, its conclusions
have been challenged by several others, as may be read here.
For
instance, dr. Benny Peiser in UK has replicated the study and found
that out of 1117 article abstracts, 34 rejected or questioned the view
that human activities are the main driving force of the observed
warming over the last 50 years. However, a closer inspection of those
34 abstracts (see here) reveals
that only two of them reject present man-made global warming, and one
of these is a petroleum industry publication. A few others express
doubt whether man-made global warming is real; these are mainly from
the early or mid 1990s. Altogether, Oreskes´ conclusions seem
warranted, and Gore´s presentation on this point is OK.
Comment:
As pointed out by several critics, the 48 scientists were part of a
political agenda. To cite CEI: ". . the scientists in
question are members of `Scientists and Engineers for Change´, a
527 political group set up to promote the Kerry for President Campaign.
Indeed, the June 21, 2004 letter to which Gore refers and from which he
quotes is first and foremost an andorsement of John Kerry for
President." It would have been most correct if Gore had mentioned this
(or not used the letter in his book).