Hi combjelly; Re: "Clathrates were probably destabilized also. After all, it has happened before...";
The claim is that methane hydrates stopped the snowball earth around 650 million years ago. But there are some inconvenient facts about this for you:
(1) Ending snowball earth caused the planet to become much more amenable to life. The release of the greenhouse gasses created a planet where life bloomed.
(2) During snowball earth, essentially the whole planet was covered with glaciers (at times) and the oceans were much colder. So the amount of methane hydrates available to release was far greater than at present. For example, see this nice powerpoint, particularly slide #26:
Methane Hydrate Hypothesis (Kennedy et al 2001)
Methane hydrates may have been more abundant during the Proterozoic ice ages than any other time in Earth history
-- Coldest intervals in Earth history
-- Abundant area available for permafrost development
-- Rapid flooding of continental basins and shelves
edgcm.columbia.edu
(3) The result of the huge pulse of greenhouse gasses did not, in fact, destroy all life on earth.
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So let's review, shall we? Y'all claimed that there could be a mass extinction that would be caused by the release of methane hydrates due to man's release of small amounts of greenhouse gasses. You claimed this was the cause of the Permian extinction but that theory fell through and got replaced by bacteria.
Then you looked up the real article and found that the release of methane hydrates has been suggested as the cause for the end of snowball earth. But this was not related to any mass extinctions. Instead, the warming up of the planet was necessary for the later explosion of life.
-- Carl
Regarding the subject of just how high CO2 can get before the Earth has all life destroyed, we're current at around 400 ppb. What do you suppose the CO2 levels were during "snowball earth"? Did you bother to read the articles? Here, I'll save you the trouble:
Although increasing levels of greenhouse gases in the Earth's atmosphere these days are seen as a harbinger of doom, millions of years ago they may have rescued the planet from a deep freeze.
Some researchers believe that at points in our planet's history — at least two, possibly three times — ice blanketed its surface, down to the equator and across the oceans, forming a "Snowball Earth."
But new research raises questions about whether a surge in carbon dioxide — one of the greenhouse gases responsible for modern, human-caused global warming — could have been responsible for the big thaw that followed the most recent Snowball Earth, about 635 million years ago. And if there wasn't a greenhouse effect big enough to melt the thick veil of ice, perhaps, the researchers suggest, Earth may not have been a big, icy snowball at the time.
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To find out how much carbon dioxide was around at the time, researchers analyzed the chemical composition of rocks taken from one of these deposits in Brazil, and the organic matter fossilized within them. The researchers also looked at data from samples from elsewhere in the world. They looked at ratios of carbon isotopes, molecules of carbon that have different atomic weights, in both the rocks and the organic matter fossilized within them. [ Big Freeze: Earth Could Plunge into Sudden Ice Age]
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They found it was much lower than expected. While previous estimates had put the carbon dioxide concentration at as much as 90,000 parts per million, this new analysis put it lower than 3,200 ppm, possibly as low as it is today, about 400 ppm.
...
livescience.com
In short, the science is still really iffy at best. But are we going to get to the 90,000 ppm, about 200x larger than it is now? Modern civilization has raised the CO2 level by something around 1.5x from the pre industrial level. How likely are we to get to 200x? That would be *zero*.
This is how unlikely the crap that you use to scare yourself is. It's not about being realistic. The fact is that lefties hate science, hate technology, and want to destroy modern civilization. You live on emotions and do not understand numbers. |
