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.'"

Comments

Correction

[Propaganda13]

It didn't end all life on Earth, and it probably wouldn't if it happened again.

Re:Rather unlikely to happen as long as we have fi

[delibes]

WTF? "another -1% of O2 and things would not ignite in the free atmosphere".

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.

Re:I wonder... (Mars climate evolution)

[Detritus]

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.

Re:we are in an ice age now!!!

[HalfFlat]

They should also include the water vapour in their climate models and this is something else they have not done. They include the 5th most abundant gas at 370 ppm (CO2) and ignore the 3rd most abundant gas which is at an average in excess of 10,000 ppm (H2O). Nevertheles it is true that H2O is quite variable and ranges from close to zero to over 70,000 PPM mostly dependant on temperature and available liquid water. Nevertheless the H2O in the atmosphere is responsible for the planet being about 30 degrees warmer than it would be if it were not present. And it is NOT is the climate models used by the IPCC.

Where on Earth did you hear that these climate models do not incorporate water vapour? That's nonsense. Of course they include water vapour. A two second google search for example brings up this paper on climate model sensitivity, which includes statements such as the following, right on the first page:

The importance of water vapour feedback was clearly demonstrated in early radiative convective model climate change experiments. For example, in the late 1960s Manabe and Wetherald (1967) showed that under assumptions of fixed relative humidity in models, water vapour changes roughly doubled the 1C warming caused by a doubling of CO2 alone. Indeed, so important is the water vapour feedback, that it is generally appreciated that without this feedback climate change would be relatively small for all credible emission scenarios.

Why are you so quick to denounce researchers investigating global warming? Why would they not have paleoclimatologists among their numbers?