Il semble y avoir une "affaire" de censure d'un rapport de l'EPA (Environnemnt Protection Agency américaine) écrit par un de ses employés, critique sur le discours alarmiste sur le RC. Selon lui, les données récentes (non prises en compte dans les derniers rapports du GIEC), vont à l'encontre des modèles climatiques , et n'expliquent pas un certain nombre de faits fondamentaux. Le rapport a été envoyé sur le site WUWT par un "insider" et est téléchargeable. Je ne prends pas position personnellement mais je pense qu'il mérite d'être lu , comme élément du dossier complexe qui me parait de moins en moins clair sur le sujet (en soi, le fait que le débat ne s'éclaircisse pas avec la multiplication des mesures, mais au contraire me semble de plus en plus incertain, tendrait à me faire penser que la situation est très loin d'être aussi bien comprise qu'on le dit).
Télecharger le rapport :
http://wattsupwiththat.com/
Un extrait le résumant ...
The principal comments are as follows:
As of the best information I currently have, the GHG/CO2 hypothesis as to the cause of global warming, which this Draft TSD supports, is currently an invalid hypothesis from a scientific viewpoint because it fails a number of critical comparisons with available observable data. Any one of these failings should be enough to invalidate the hypothesis; the breadth of these failings leaves no other possible conclusion based on current data. As Feynman (1975) has said failure to conform to real world data makes it necessary from a scientific viewpoint to revise the hypothesis or abandon it (see Section 2.1 for the exact quote). Unfortunately this has not happened in the global warming debate, but needs to if an accurate finding concerning endangerment is to be made. The failings are listed below in decreasing order of importance in my view:
1. Lack of observed upper tropospheric heating in the tropics (see Section 2.9 for a detailed discussion).
2. Lack of observed constant humidity levels, a very important assumption of all the IPCC models, as CO2levels have risen (see Section 1.7).
3. The most reliable sets of global temperature data we have, using satellite microwave sounding units, show no appreciable temperature increases during the critical period 1978-1997, just when the surface station data show a pronounced rise (see Section 2.4). Satellite data after 1998 is also inconsistent with the GHG/CO2/AGW hypothesis
4. The models used by the IPCC do not take into account or show the most important ocean oscillations which clearly do affect global temperatures, namely, the Pacific Decadal Oscillation, the Atlantic Multidecadal Oscillation, and the ENSO (Section 2.4). Leaving out any major potential causes for global warming from the analysis results in the likely misattribution of the effects of these oscillations to the GHGs/CO2 and hence is likely to overstate their importance as a cause for climate change.
5. The models and the IPCC ignored the possibility of indirect solar variability (Section 2.5), which if important would again be likely to have the effect of overstating the importance of GHGs/CO2.
6. The models and the IPCC ignored the possibility that there may be other significant natural effects on global temperatures that we do not yet understand (Section 2.4). This possibility invalidates their statements that one must assume anthropogenic sources in order to duplicate the temperature record. The 1998 spike in global temperatures is very difficult to explain in any other way (see Section 2.4).
7. Surface global temperature data may have been hopelessly corrupted by the urban heat island effect and other problems which may explain some portion of the warming that would otherwise be attributed to GHGs/CO2. In fact, the Draft TSD refers almost exclusively in Section 5 to surface rather than satellite data.
The current Draft TSD is based largely on the IPCC AR4 report, which is at best three years out of date in a rapidly changing field. There have been important developments in areas that deserve careful attention in this draft. The list includes the following six which are discussed in Section 1:
• Global temperatures have declined—extending the current downtrend to 11 years with a particularly rapid decline in 1907-8; in addition, the PDO went negative in September, 2007 and the AMO in January, 2009, respectively. At the same time atmospheric CO2 levels have continued to increase and CO2 emissions have accelerated.
• The consensus on past, present and future Atlantic hurricane behavior has changed. Initially, it tilted towards the idea that anthropogenic global warming is leading to (and will lead to) to more frequent and intense storms. Now the consensus is much more neutral, arguing that future Atlantic tropical cyclones will be little different that those of the past.
• The idea that warming temperatures will cause Greenland to rapidly shed its ice has been greatly diminished by new results indicating little evidence for the operation of such processes.
• One of the worst economic recessions since World War II has greatly decreased GHG emissions compared to the assumptions made by the IPCC. To the extent that ambient GHG levels are relevant for future global temperatures, these emissions reductions should greatly influence the adverse effects of these emissions on public health and welfare. The current draft TSP does not reflect the changes that have already occurred nor those that are likely to occur in the future as a result of the recession. In fact, the topic is not even discussed to my knowledge.
• A new 2009 paper finds that the crucial assumption in the GCM models used by the IPCC concerning strongly positive feedback from water vapor is not supported by empirical evidence and that the feedback is actually negative.
• A new 2009 paper by Scafetta and Wilson suggests that the IPCC used faulty solar data in dismissing the direct effect of solar variability on global temperatures. Other research by Scafetta and others suggests that solar variability could account for up to 68% of the increase in Earth’s global temperatures.
These six developments alone should greatly influence any assessment of “vulnerability, risk, and impacts” of climate change within the U.S., but are not discussed in the Draft TSD to my knowledge. But these are just a few of the new developments since 2006. Therefore, the extensive portions of the EPA’s Endangerment TSD which are based upon science from the IPPC AR4 report are no longer appropriate and need to be revised before a TSD is issued for comments.
Not only is some of the science of the TSD out-of-date but there needs to be an explicit, in-depth analysis of the likely causes of global warming in my view. Despite the complexity of the climate system the following conclusions in this regard appear to be well supported by the available data (see Section 2 below):
A. By far the best single explanation for global temperature fluctuations appears to be variations in the PDO/AMO/ENSO. ENSO appears to operate in a 3-5 year cycle. PDO/AMO appear to operate in about a 60-year cycle. This is not really explained in the draft TSD but needs to be, or, at the very least, there needs to be an explanation as to why OAR believes that these evident cycles do not exist or why they are so unimportant as not to receive in-depth analysis.
B. There appears to be a strong association between solar sunspots/irradiance and global temperature fluctuations. It is unclear exactly how this operates, but it may be through indirect solar variability on cloud formation. This topic is not really explored in the Draft TSD but needs to be since otherwise the effects of solar variations may be misattributed to the effects of changes in GHG levels.
C. Changes in GHG concentrations appear to have so little effect that it is difficult to find any effect in the satellite temperature record, which started in 1978.
D. The surface measurements (such as HADCRUT) are more ambiguous than the satellite measurements in that the increasing temperatures shown since the mid-1970s could either be due to the rapid growth of urbanization and the heat island effect or by the increase in GHG levels. However, since no such increase is shown in the satellite record it appears more likely that urbanization and the UHI effect and/or other measurement problems are the most likely cause. If so, the increases may have little to do with GHGs and everything to do with the rapid urbanization during the period. Given the discrepancy between surface temperature records in the 1940-75 and 1998-2008 and the increases in GHG levels during these periods it appears even more unlikely that GHGs have as much of an effect on measured surface temperatures as claimed. These points need to be very carefully and fully discussed in the draft TSD if it is be scientifically credible.
E. Hence it is not reasonable to conclude that there is any endangerment from changes in GHG levels based on the satellite record, since almost all the fluctuations appear to be due to natural causes and not human-caused pollution as defined by the Clean Air Act. The surface record is more equivocal but needs to be carefully discussed, which would require substantial revision of the Draft TSD.
F. There is a significant possibility that there are some other natural causes of global temperature fluctuations that we do not yet really understand and which may account for the very noticeable 1998 temperature peak which appears on both the satellite and surface temperature records. This possibility needs to be fully explained and discussed in the Draft TSD. Until and unless these and many other inconsistencies referenced in these comments are adequately explained it would appear premature to attribute all or even most of what warming has occurred to changes in GHG/CO2 atmospheric levels.
Zan, zendegi, azadi. Il parait que " je propage la haine du Hamas".
. L'énergie disponible pour se transformer en énergie mécanique ne dépend pas de la température en elle-même, mais d'un différentiel de température (par exemple les cyclones se forment lorsque l'eau est suffisamment chaude par rapport à l'air). Le RC n'implique pas a priori que ce différentiel augmente (et meme , les poles sont censés se réchauffer plus que les tropiques...). Donc si il y a un effet prédit, ça ne peut etre qu'en raison de rétroaction supercompliquées, et pas le résultat d'un raisonnement simple du genre "plus c'est chaud, plus y a d'énergie".... mais bon pour le moment comme je disais, rien de très mesurable.
