An Inconvenient Truth is Online!
The entire movie has been webbed, making possible a point-by-point discussion with reference to the original. Don't know how long it'll last, but here are the links to Gore's movie _An Inconvenient Truth:
part 1 part 2.
Gore starts out by attributing a version of "The trouble with people is not that they don't know but that they know so much that ain't so." to Mark Twain. Twain never said that, and since Gore gives no source, you can't check his claim. An inauspicious beginning. The actual source for that quote is Josh Billings, who also wrote these gems:
"I have lived in this world just long enough to look carefully the second time into things that I am most certain of the first time. "13 minutes in, Gore lies with statistics by cutting off the bottom of a C02 chart. The camera zooms in as it scrolls across the page so you can't see the scale, but it looks like about a 2% increase over 40 years. The book How to Lie With Statistics points out that chopping off the bottom of a chart, carefully choosing how much data to include and rescaling the resulting chart to fit the available space is a good way to turn an insignificant rise or fall into one that looks scary. If you do that twice, say, once with CO2 and once with temperature, you're pretty much guaranteed that the overall trend will look somewhat similar if both curves are increasing at all.
"Don't ever prophesy; for if you prophesy wrong, nobody will forget it; and if you prophesy right, nobody will remember it. "
14:00 shows the chart in red with no scale at all. As if the sheer fact of a number increasing were scary without regard to how much it is increasing.
15:00 red line, no scale.
17: "Glaciers are so beautiful, but those who go to see 'em, here's what they're seeing now." (Shows a calving video, falsely implying that calving into the water wouldn't happen without warming and that no glaciers are growing.)
18: shows glaciers receding, as if this is an unambiguously bad thing.
19: On ice cores, a somebody told Gore "Right here is where the US passed the clean air act." Gore adds "And I couldn't believe it, but you could see the difference with the naked eye - a couple of years after that law was passed, it's very clearly distinguishable." Gore is either mistaken or lying about this; it's not believable.
20: Shows a hockey stick. Doesn't mention it's not all charting the same information or the divergence issue or that - contrary to his chart - a great deal of evidence suggests the Medieval Warming Period was warmer than today. Now that we've had the NAS study and the Wegman report, nobody should present the Hockey Stick in this fashion.
20:30: compares (reconstructed) temperature and CO2 concentration side by side.
21:50 Gore now shows the graphs one above the other - which is a bit better - and asks "did they ever fit together?" but never superimposes or calculates a difference to show which moves first or to what degree they are similar. He never mentions that CO2 changes generally trail temperature changes. If you pause the video and look carefully you can see this - often the uptick in temperature comes first.
23:30: Gore implies that higher CO2 means higher temp rather than the reverse, never mentions the scale on the chart or percentage increase. Also, the predicted increase is outdated.
28:38 Gore says that according to atmospheric measurements, "the hottest (year) of all was 2005." Nope; 2005 is in a dead heat with 1998. To make the stronger claim, Gore is either cherrypicking his source or silently switching to Northern Hemisphere temperature.
30: Gore claims when the oceans are warmer we get more storms. (unproven, dubious)
37: The plot of "number of storms and floods" shows growth. This is true, but misleading because - according to those who study storms - the frequency is primarily driven by other things than temperature. Gore claims 2005 will be "off that chart". Was this true? In any case, 2006 won't be.
39: Lake Chad nearly dried up in 1908 and 1984; the fact that it also did so again recently is more related to changes in irrigation than global warming. Gore is now cherry-picking to find any random recent bad event to pin on AGW. He also did this with Katrina, but note that 2006 was an extremely mild hurricane season.
42:30 "Drunken trees". Gore thinks it's bad that the permafrost is thawing.
43:10: Gore shows a plot of "Alaskan Winter Tundra Travel Days". Hallelujah!! It's an honest chart! Possibly the first we've seen. The scale is clearly shown and starts at zero, so the chart does not create a false impression of disproportionate movement. It's still not clear why the trend being shown is such a bad thing - it implies the need to build roads rather than trek straight across the countryside - but the chart is honest and does bear some relation to Gore's thesis. Phew! Things are looking up!
44:10: Whoops, I spoke too soon; he's already at it again! This plot of "Sea Ice Extent" (measured in millions of kilometers squared) shows what Gore calls "a precipitous drop" largely because he's cut off the scale at 10 instead of zero. By mis-scaling and zooming in as the chart is drawn so you can't see the scales by the time the relevant data appears, this chart leaves the viewer with the visual impression that this measurement has roughly dropped in half but actually it's declined from around 13 to around 11. Gore then says "It has diminished by 40% in 40 years." His own chart does not show this. Eyeballing it, I make out the high point of the chart as 14 and the low as 11.3 - that's a 20% drop if you cherrypick the endpoints well enough. (The actual decline is around 15% if you compare two relative highs or relative lows or if you take a moving average.)
45:24: Polar bears drowning. Al Gore notes that a study found that some polar bears drown while swiming long distances for food. Gore claims that "they didn't find this before" but that's because they weren't looking for it before. There is no data to support a claim that more polar bears are drowning now than have been in the past, nor are polar bears endangered.
End of Part 1.
0:54 Gore says "If we have an increase of five degrees (F), which is on the low end of the projections..." Those are old projections, and he doesn't say how long it would take.
3:25 The thermohaline currents shutting down is just a scare story; there's no evidence for it as a likely possibility. He says "we'll get back to that later" but never does so.
6:00 The caterpillars and chicks story. Why do we care more about these chicks than the butterflies they eat and whatever the chicks were competing against?
6:38 The chart of "frost days" versus "Number of invasive species" is correctly scaled to zero! And he superimposes them to see the relationship between the two! Hurray! What does this mean? Many species do better when there's less frost. Seems like a good thing generally, even if a few of the species who profit by it can be called "invasive".
7:06 Pine beetle. Another cherry-picked example. Somehow no endangered species that are helped by warming reach Gore's radar.
7:23 Claims various towns (Nairobi and Harare) were founded because they were "just above the mosquito line" but that line has increased due to warming. As I understand it, Gore is wrong here -- malaria has been documented at an altitude of 2,500 metres while Nairobi and Harare are at about 1,500 metres. The increased malaria problem in Nairobi is largely due to local land use changes and population pressures, not global warming.
7:42: "We've had 30 new diseases that have emerged in the last quarter century." Yes, but none are attributable to global warming according to those who study them. Good quotes here.
9:30: talks about ice loss in the Antarctic Peninsula. Doesn't mention that the Antarctic as a whole has in many recent years gained more ice than it has lost - the Peninsula has been a local exception to an overall trend that was often neutral or in the other direction.
11: Mentions in passing that various people have had to move to New Zealand due to rising water, implying this was caused by antarctic melting. Doesn't name the countries, so we can't check whether sea level rises have actually occurred there - the pacific is falling in some parts.
12: "if this were to melt, or if greenland were to, sea level would rise 20 feet. Doesn't mention that given current sea level trends it would take over a thousand years.
13:40 "If greenland broke up and melted, or if half of greenland and half of antartica broke up and melted, this is what would happen to the sea level in florida." Starts showing computer animations of a 20 foot rise. Doesn't mention it would take a thousand years.
14:43: "Imagine the impact of a hundred million or more refugees." If the change happens, it will be imperceptively slow year-to-year and so far in the future that the people to whom it happens will be immeasurably richer than we are now and correspondingly more able to handle changes. That is, if we don't let scare stories cause us to shut down the engines of progress in the meantime.
18: Honest charts on population. Yay!
22:30: Honest charts on carbon emissions by regions - they start at zero.
23: The parable of the frog. Gore claims a frog in lukewarm water won't jump out as the temperature rises. This is an urban myth. The fact that real frogs jump out when it gets too hot should lead us to think people will act if and when we, too, are actually threatened.
27: Refers to the Naomi Oreskes literature study on "Climate change". Few published studies that include the string "climate change" explicitly reject the consensus view in their abstract, which is all that Oreskes read. However, surveys of scientists have found a wide range of views including quite a lot of dissent. Perhaps the presence of a "consensus view" is merely making it hard to publish papers that explicitly reject that view. Or perhaps the problem is the phrase "climate change". If you search instead for "climate variability" it's apparently possible to find published studies that reject the consensus of climatologists, though they aren't always labeled as such.
30: Gore expresses concern that scientists are being browbeaten into expressing views that are not their own. That concern works both ways; it doesn't only support his own view. For instance, the IPCC "Summary for Policymakers" has been known to include wording the individual scientists don't support.
31:15: Gore displays an Upton Sinclair quote: "It is difficult to get a man to understand something when his salary depends upon his not understanding." That's actually the correct attribution! Huzzah! (Note that one might apply the quote to Gore himself, as chairman of a company that is heavily invested in "sustainability" technologies.)
31:30: Gore asks "Do we have to choose between the economy and the environment?"
32:52: Gore says "If we do the right thing, we're going to create a lot of wealth and a lot of jobs."
35: Another dishonest graph - the base of the fuel economy graph starts at 20mpg, which exaggerates the difference between countries.
35:42: Gore claims China's fuel economy standards are way above ours. However, they don't meet their own standards, and their cars suck in every other way, particularly safety. Mileage is a nice feature of a car but it's not the only important feature; there are tradeoffs to make. We don't want to pay the cost in lower safety, less carrying capacity, etcetera.
37:30: Hey, it's another chart that starts at zero! Gore claims we can reduce our emissions to 1970 levels with known existing technologies. He doesn't give any indication of cost or whether making the changes he advocates would pass a cost-benefit analysis.
38: Gore says "We can make choices to bring our individual carbon emissions to zero." I rather doubt that, short of suicide...
39: Gore supports Kyoto. Ugh.
In summary: there seems to be a human need to believe in doom and gloom scenarios. Gore resembles an old time revival preacher, scouring the world for evidence that things are getting worse so he can claim the end of the world is at hand. But if the evidence were as solid as he claims, he wouldn't need to lie about it. He could present honest charts that start at zero, are clearly sourced, and clearly distinguish between actual data and computer "projections". He wouldn't need to selectively present only the data that supports his own side and claim a false consensus.
The fact that Gore needs to engage in this sort of rhetorical slight of hand indicates a weak case.