Tag Archive: mass extinction

A part of my John Everett series – read more: 0/I - II.0 - II.5 - II.75 -  III.0 - III.3 - IV.0 - IV.4 - IV.8 - V - VII - VIII - Full Report 

The last part of Dr. Everett’s testimony presents his conclusions. Much of it is simply reiteration ofclaims he has already

Fig. 1. The rate of change in atmospheric carbon dioxide, based upon gas samples from three ice cores (Law Dome, Taylor Dome, and Vostok) and direct measurements at Mauna Loa Observatory. Data courtesy of NOAA Paleoclimatology and ESRL (see endnotes). Click for full.

made, but he also takes the opportunity to thicken the smoke screen just a little bit more. Some parts are mundane: ‘The most important approach [...] is to examine what happened during past times.’ I completely agree! See Fig. 1. But other parts are more problematic. Here’s a quick flyby:

He claims ‘There is no reliable observational evidence of negative trends that can be traced definitively to lowered pH of the water’, and dismissing experimental results. However, studies meeting his criteria exist, and they demonstrate negative consequences.

He demands that experiments be run over sufficient generations to allow for adaptation, but he doesn’t say how many generations are sufficient. This leaves any study demonstrating negative effects open to rejection by moving the goalposts for sufficient experimental length. Ironically, a paper which Dr. Everett had earlier claimed cast doubt upon acidification studies mentions the short time scales of current experiments, but concludes that it could well be masking the more severe effects of acidification:

‘Although suppression of metabolism under short-term experimental conditions is a “sublethal” reversible process, reductions in growth and reproductive output will effectively diminish the survival of the species on longer time-scales.’  (Fabry et al. 2008)

Conclusions he doesn’t like can be further dismissed: ‘If there were [an observation of deletrious effects of acidification], it would be suspect because there is insignificant change relative to past climates of the Earth.’ We have seen this statement to be simply incorrect. He fails to give further support for this position, stating that ‘Scientific studies, and papers reviewing science studies, have similar messages’, but not giving us any examples.

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A part of my John Everett series – read more: 0/I - II.0 - II.5 - II.75 -  III.0 - III.3 - IV.0 - IV.4 - IV.8 - V - VII - VIII - Full Report 

Last time we looked at Dr. Everett’s testimony, we examined his claim that, because carbon dioxide levels have been higher in the past, increasing levels are not alarming now. His argument is flawed, because although CO2 levels have changed, they usually change only very slowly. Now, they’re changing abruptly. Graphs of Deep Time can be intuitively misleading, because they collapse time scales and it can be hard to compare the rates of change from one image to the next. For example, this next graph shows information that we have gathered from looking at  gasses trapped in Antarctic ice. It’s obvious that the climate changes over Deep Time- but is it obvious from this graph how historical rates of change compare to modern rates?

Paleoclimatic and paleogeochemical data gathered from the Vostok ice core. Temperature (red) and carbon dioxide (blue) go up and down on these time scales - but its the rate that really matters. Click for sauce.

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