Point-By-Point Demolition Of The "Nine Errors" From Gore's Movie - Realclimate

[hatrack]

Last week, a UK High Court judge rejected a call to restrict the showing of Al Gore's An Inconvenient Truth (AIT) in British schools. The judge, Justice Burton found that "Al Gore's presentation of the causes and likely effects of climate change in the film was broadly accurate" (which accords with our original assessment). There has been a lot of comment and controversy over this decision because of the judges commentary on 9 alleged "errors" (note the quotation marks!) in the movie's description of the science. The judge referred to these as 'errors' in quotations precisely to emphasize that, while these were points that could be contested, it was not clear that they were actually errors (see Deltoid for more on that).

There are a number of points to be brought out here. First of all, "An Inconvenient Truth" was a movie and people expecting the same depth from a movie as from a scientific paper are setting an impossible standard. Secondly, the judge's characterisation of the 9 points is substantially flawed. He appears to have put words in Gore's mouth that would indeed have been wrong had they been said (but they weren't). Finally, the judge was really ruling on how "Guidance Notes" for teachers should be provided to allow for more in depth discussion of these points in the classroom. This is something we wholehearted support - AIT is probably best used as a jumping off point for informed discussion, but it is not the final word. Indeed, the fourth IPCC report has come out in the meantime, and that has much more up-to-date and comprehensive discussions on all these points.

EDIT

# Climate impacts on the ocean conveyor The movie references the Younger Dryas event that occurred 11,000 years ago when, it is thought, a large discharge of fresh water into the North Atlantic disrupted the currents, causing significant regional cooling. That exact scenario can't happen again, but similar processes are likely to occur. The primary unresolved scientific issue regards how quickly the circulation is likely to change as we move forward. The model simulations in the latest IPCC report show a slowdown in the circulation - by about 30% by 2100 - but there is much we don't understand about modeling that circulation and future inputs of freshwater from the ice sheets, so few are willing to completely rule out the possibility of a more substantial change in the future. Further discussion on what this really means and doesn't mean is available here and here.

# CO2 and Temperature connections in the ice core record Gore stated that the greenhouse gas levels and temperature changes over ice age signals had a complex relationship but that they 'fit'. Again, both of these statements are true. The complexity though is actually quite fascinating and warrants being further discussed by those interested in how the carbon cycle will react in the future. We've discussed the lead/lag issue previously. A full understanding of why CO2 changes in precisely the pattern that it does during ice ages is elusive, but among the most plausible explanations is that increased received solar radiation in the southern hemisphere due to changes in Earth's orbital geometry warms the southern ocean, releasing CO2 into the atmosphere, which then leads to further warming through an enhanced greenhouse effect. Gore's terse explanation of course does not mention such complexities, but the crux of his point–that the observed long-term relationship between CO2 and temperature in Antarctica supports our understanding of the warming impact of increased CO2 concentrations–is correct. Moreover, our knowledge of why CO2 is changing now (fossil fuel burning) is solid. We also know that CO2 is a greenhouse gas, and that the carbon cycle feedback is positive (increasing temperatures lead to increasing CO2 and CH4), implying that future changes in CO2 will be larger than we might anticipate.

EDIT

Much more at:

http://www.realclimate.org/index.php/archives/2007/10/convenient-untruths/

[MelissaB]

1. Bookmarked for future reference. n/t

[DesertRat]

2. Kick

:kick: