Slashdot Mirror
Mass Extinctions from Global Warming?
uncleO writes "The current issue of Scientific American has an interesting article,
Impact from the Deep, about the possible causes for the five major global extinctions. It contends that only the most recent one was caused by a 'dinosaur killer' asteroid impact. Evidence suggests that the others were caused by 'great bubbles of toxic H2S gas erupting into the atmosphere' from the oceans due to anoxia." From the article: "The so-called thermal extinction at the end of the Paleocene began when atmospheric CO2 was just under 1,000 parts per million (ppm). At the end of the Triassic, CO2 was just above 1,000 ppm. Today with CO2 around 385 ppm...climbing at an annual rate of 2 ppm...to 3 ppm, levels could approach 900 ppm by the end of the next century."
Lots I want to reply to... :)
Probably the best source for scientific data and reliable modelling comes from the intergovernmental panel on climate change [ipcc.ch]. The last full report was from 2001 and is fully available on line and for free. I stupidly bought the books. The amount of synthesis of data performed is HUGE and from literally thousands of scientists in the field. It is truly the definitive work in progress. Due to the nature of science and the complex chaotic mechanisms of climate the models cannot be 100% conclusive; however, the four prospective models used have hypothesized the expected changes since 2001 fairly well. The four models assumed different scenarios of human responses to climate change. The four models being a reduction in CO2 emissions, constant increases, moderate increases and large increases in CO2 emissions. The effects of these models are classified according to a likelihood scale and associated percentages. Since the publication of the report, we have had 5 years to compare and contrast the models with reality. The modelling has done quite well. I suggest anyone who is interested read the synthesis report. The rest would take you a year or so to read
Since the report, due to the political tenderness of the topic, if anything, has been underreported and cautiously forwarded. It seems that one area that was underestimated in impact was the positive feedback mechanisms invovled in lost albedo and permafrost thaw. Also, the effects due to water vapor and cloud formation are still difficult to understand and predict.
As a teacher, I agree that we MUST listen and respond to the experts in the field and not political/religious/uninformed theorists. IE> michael Creighton and his ' State of Fear'. Some of the scientists he interviewed respond to his book at realclimate.org as well as a 'book report' in science magazine. Both are telling of the political nature of the topic.
Finally, we need to consider the larger manifestitions of 'global warming' with respect to increases in ocean acidity, altered weather patterns with respect to agriculture, etc. It is the unpredicatable spinoffs of global warming/climate change that will threaten society. Lack of food, lack of clean water and the wars associated with future conflicts we need to worry about.