"far more than a hot day and wet feet"

[ironphoenix]

peristaltor wrote a good summary post about mass extinctions (90+%) and their relation to global warming; scary stuff! He is summarizing things drawn from several sources, which I will have to look into separately.

I followed the link to one of his sources, an interview with the Chief Scientist at NASA's Langley Research Center, from which the subject line is drawn, and that gives even more stuff to think about (much of it going considerably beyond the energy and extinction question).

Both are highly recommended reads; the former takes less time to get through, but the latter is somewhat jaw-dropping in scope.

Comments

[jagash.livejournal.com]

The fun of positive reinforcement in chaotic systems, you get all sorts of interesting disasters looming.

[ironphoenix.livejournal.com]

Which leads to another interesting question: what brings it back?

[jagash.livejournal.com]

In order to reverse one of those cascades once it passes a threshold, you need to apply far more force in the opposite direction to get it to revert if even possible. Let's say that 5% of coastal waters as dead zones is sustainable and generally fine but that value is creeping towards a threshold of 15. In order to push it back into a stable state, you don't need to push it to 5% again but rather to 1%. Either manipulate a larger scale variable (such as CO2 levels in the air) or many many smaller scale variables (reclaiming each individual dead zone with oxygenation and other treatment.

Yeah, this is my particular specialty in ecology.

[ironphoenix.livejournal.com]

But what is the mechanism by which this actually happened in the (pre-)historical instances theorized? For the theory to be credible, it has to explain this part of the evidence too!

[jagash.livejournal.com]

Mechanism for increase of CO2: Large scale fires of the once in a century variety, meteor strikes or volcanoes.

Mechanisms for decrease in CO2: Increases in phytoplankton communities fixing more CO2 with the CO2 levels hurting their predators and increasing their energetic yield slightly. Increased temperature increases the space occupied by deciduous trees compared to conifers. Both those factors and the natural slight bias towards decreasing CO2 levels would moderate the levels within a few hundred years. Ya know, if you don't have humans getting in the way.

[ironphoenix.livejournal.com]

Increases in phytoplankton communities fixing more CO2

That's exactly what the author of Under a Green Sky is saying won't happen, because "green sulfur bacteria... [and] other bacteria ... produce toxic amounts of hydrogen sulfide, and the flux of this gas into the atmosphere, where it breaks down the ozone layer, and the subsequent increase in ultraviolet radiation from the sun kills much of the photosynthetic green plant phytoplankton."

If he's right, what's left to stop the avalanche?

[jagash.livejournal.com]

Yes, sulfur bacteria can do that. Thing is that sulfur bacteria only thrive in anoxic conditions, such as water without oxygen in it. Sulfur bacteria typically only live in sulfur rich, oxygen deprived and chemically active zones such as black smokers or industrial waste. Phosphorus runoff does cause dead zones along the coast and furthers the process, but not enough to cause that amount of snowballing solo. The whole UV radiation killing photosynthetic phytoplankton is bull though. Heck, the product of those bacteria is actually Sulfate which (to the best of my memory) actually blocks sunlight input and accordingly decreases global temperatures in that fashion.

Yes, dead zones are a major problem and some green sulfur bacteria can contribute to making a bigger mess but that alone isn't unstoppable. It's in a different stable state which is less disturbed then some of the others.

[ironphoenix.livejournal.com]

The whole UV radiation killing photosynthetic phytoplankton is bull though. Heck, the product of those bacteria is actually Sulfate which (to the best of my memory) actually blocks sunlight input and accordingly decreases global temperatures in that fashion.

Well, that's good to hear!

[soul-diaspora.livejournal.com]

I got as far as "in league with their liberal agenda" and stopped reading.

[http://users.livejournal.com/niall_/]

I didn't, but I added a grain of (sea) salt. Someone at the bottom of the comments make a good reality-test argument, but nonetheless, a few facts can still emerge, stuff going deeper than the usual exploration of the issue in media. And exploring his sources independently can still be viable. :)

[ironphoenix.livejournal.com]

Yeah, pretty much; shiva_kun raises a good point.

[ironphoenix.livejournal.com]

Fair enough... the source material is less inclined towards name-calling.