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."

Comments

Re:Fearmongering is not the way to do this.

[Clirion]

Did you actually read what he did say? We have every reason to reduce emissions. I'm absolutely pro-emission-reduction; cleaner air is better for every living thing and that's a perfectly good justification to swing me. Seems to me he may actually want to reduce the emissions, just the hype around it is bad.

Just a thought....

[grishknash]

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.

Not Human Nature

[ChronoFish]

One of things that we have to accept about humans is that they are part of nature. It's not natural for humans (as a population, not necessarily individuals) to restrain themselves.

What this means (to me) is that the destruction that humans brings (aka man-made) is also natural. It is also natural for humans to destruct to the point of no-return - i.e. humans will use up every last natural-resource until there is no longer a natural-resource to use.

Whaling and fishing are great examples. The Atlantic Ocean used to have an abundance of (sperm) whales. But the human race killed them off - that didn't stop the whalers of course. Rather than realizing the impact and looking for alternatives, they setup long complex shipping routes. Boats from Nantucket (North Eastern US) would set sail and round Argentina (South America) and then exploit the waters of Hawaii and Singapore in the Pacific. Eventually killing off the whales there as well.

The reason for hunting whales? Primarily whale blubber -which was boiled down to oil - which was used as a power source. Eventually the stock of sperm whales dried up in the pacific as well - forcing humans to come up with an alternative - which they did (petrol) - thereby officially killing the whaling industry. (Sure Japan is still at it - but mostly for the meat which focus on other types of whales).

The point is that humans will not restrain themselves or conserve (with some notable exceptions of course) their natural resources. And this is a natural part of human nature - which is part of nature.

So yeah - we are doomed to repeat the process (there are countless examples) and the end result is that we will wipe ourselves out. But that is part of nature - to thrive until starvation. Every population does it. Name one animal that does not gorge themselves - even if it means death to the species.....

-CF

Re:Fearmongering is not the way to do this.

[HiThere]

I'm not totally convinced that "passivated glass brick" is the optimum waste disposal. It's certainly, however, better than what we do with coal (dump it into the atmosphere). I'm also not convinced that it's feasible to safely bury CO2. Some of those disposals have failure modes that are quite frightening.

To me an optimal disposal method for radio waste would packetize it in a way that would allow it to be recovered if that became economically viable. (Say, for use in a fast-breeder.) But you also want it dispersed so that it didn't undergo "mini-chains" that caused it to burn itself up too quickly. Small blobs in flat sheets separated by about a foot (of plaster? cement?) sounds good. The sheets could be as large as is convenient to handle. Some PVC mimic would be a good choice for what to make them out of. That way they could be loosely rolled for transport. (Unless someone things it worthwhile to build a cadmium spiral cylinder to store them in. Or to transport them flat separated by cadmium sheets. Not likely. Just keep them separated, and make sure that no one sheet will go critical even if you roll it tightly--and then ensure that it is rolled loosely (with styrofoam spacers?. (That should be easy. This is waste, not fuel.)

The thing is, while the stuff is encased in plastic it's only dangerous to folk that are near it. It's not explosive. So you need to keep it cool enough to not melt the plastic...but you've already used it as throughly as is reasonably economic, so it's not super hot thermally.

OTOH, if you just want it to go away and never return, then passivated glass bricks are hard to beat. You could even use them to pre-heat water for a steam plant for the first decade or so. (I'm presuming that the passivation includes something like sealing the bricks in paraffin so that water can't leach through... if you plan for that, then you don't need to worry about it's happening accidentally. Then put the bricks in a plastic bag before you dump them in the water to heat it, and all should be well.)