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When Microbes Ate the Ocean
museumpeace writes "When /. discussed a story about microbes that could break down water as a hydrogen source, many commentors went off on a tangent joking about runaway germs eating the oceans. Now, prof Joe Kirschvink and students at CalTech propose that indeed, the worst iceage ever, which nearly ended life on earth 2.3 billion years ago, was the result of algae evolving the ability to break down water and flooding the atmosphere with oxygen. The absence of oxygen consuming organisms at that time is said to have lead to destruction of atmospheric methane which had hitherto warmed the earth. The professor concludes: 'We haven't had a Snowball in the past 630 million years, and because the sun is warmer now it may be harder to get into the right condition. But if it ever happens, all life on Earth would likely be destroyed.'"
It didn't end all life on Earth, and it probably wouldn't if it happened again.
Did you study arts at college? Whether something burns depends on the heat you expose it to, the type of material itself, and also (yes) the availability of oxidiser (O2 in the air). Methane gas, coal, and all your other favourite fossil fuels will burn in 19%-O2 air just fine. They might produce marginally more carbon monoxide, but they wouldn't just stop.
If combustion was that sensitive, I think most candles wouldn't burn because they'd use up the oxygen around them to quickly. And blowing gently on a flame would always put it out rather than increase it, because there's less O2 (about 16%?) and more CO2 in your exhaled breath.
This is not a sig
I think that it is more likely that Mars was doomed by its relatively small mass. Its escape velocity is only 5 km/s, and it doesn't have a strong magnetic field to protect it from the solar wind. This means that the atmosphere will rapidly leak into space.
Mea navis aericumbens anguillis abundat