New perspective on previous episodes of global warming

[JavaScriptDonkey]

Research, research everywhere and not an Elephant in sight....

Dr Philip Sexton's research published in Nature (March) and briefly discussed here.

It has uncovered the likely cause of repeated episodes of natural global warming 50 million years ago in the Eocene epoch, when Earth last experienced the elevated temperatures and atmospheric carbon dioxide levels predicted for the end of this century.

and

Recent discoveries of a number of additional, but more modest, hyperthermals during the Eocene have led scientists to assume that they, too, were triggered by the same thing: carbon release from ‘fossil fuel’ reservoirs into Earth’s atmosphere.

and

“We think that large amounts of carbon dioxide were repeatedly released into the atmosphere, and subsequently rapidly taken back up again, by the ocean,” said Dr Sexton. Specifically, they implicate a much larger-than-modern, and dynamic, oceanic reservoir of dissolved organic carbon.

So, given sufficiently healthy oceans (with we do not have) higher atmospheric CO2 concentrations are recoverable on geologic time scales.

I wonder what stops the ocean creatures sucking all the CO2 up and thereby killing all plant life?

[UndercoverElephant]

Ocean creatures do not suck up CO2. They suck up oxygen and produce CO2.

What point are you trying to make?

[biffvernon]

wonder what stops the ocean creatures sucking all the CO2 up and thereby killing all plant life?

It's a reasonably well understood process. The biggest carbon sink is limestone rock. This is made by sea creatures that have shells made of calcium carbonate. To accumulate limestone conditions have to be just right, enough carbon and calcium dissolved in the water but not too much. There is no way that they can 'suck all the CO2 up and thereby kill all plant life'. Eventually the limestone is uplifted at exposed to weathering, where again the delicate balance of carbonic acid in the rain affects the rate of solution and return to the sea.

Of course the important thing to remember is that this all happens on a geological timescale, far removed from the timescale that anthropogenic warming is now imposing on the natural systems that produced climate change in the Eocene.

[JavaScriptDonkey]

wonder what stops the ocean creatures sucking all the CO2 up and thereby killing all plant life?

It's a reasonably well understood process. The biggest carbon sink is limestone rock. This is made by sea creatures that have shells made of calcium carbonate. To accumulate limestone conditions have to be just right, enough carbon and calcium dissolved in the water but not too much. There is no way that they can 'suck all the CO2 up and thereby kill all plant life'. Eventually the limestone is uplifted at exposed to weathering, where again the delicate balance of carbonic acid in the rain affects the rate of solution and return to the sea.

Of course the important thing to remember is that this all happens on a geological timescale, far removed from the timescale that anthropogenic warming is now imposing on the natural systems that produced climate change in the Eocene.

That's not exactly what the research indicates. Certainly there is a limestone based cycle but the time scale on that is, well, glacial.

The research shows that it is the state of the oceans and their ability to 'deal' with CO2 in the atmosphere that is critical. By 'deal' I've assumed we are talking predominantly about the creation of exoskeletons but I could well be wrong.

As far as the oceans are concerned there is no such thing as a natural amount of atmospheric CO2 - there is only CO2. Sometimes it (including the life IN it) flourishes and uses lots, sometimes it dies and uses very little.

Why is there 'no way'? I see no mechanism that would limit atmospheric CO2 resource depletion amongst, say trilobites. Should there be an explosion of CO2 using oceanic life it would just be another case of over shoot and die off.

[JavaScriptDonkey]

Ocean creatures do not suck up CO2. They suck up oxygen and produce CO2.

What point are you trying to make?

I think you are confused. Lots of CO2 is used by oceanic life to form exoskeletons. It is a well documented process.

[UndercoverElephant]

The research shows that it is the state of the oceans and their ability to 'deal' with CO2 in the atmosphere that is critical. By 'deal' I've assumed we are talking predominantly about the creation of exoskeletons but I could well be wrong.

There are two things happening at the moment which have never previously happened. The first is that human activity is pumping lots of greenhouse gases into the atmosphere (not just burning fossil fuels but also keeping lots of methane-producing cattle, etc...). The second is that humans have already chopped down more than half of the naturally-existing woodland (globally) and are now busily chopping down the rest.

The world's oceans have already acted as a massive sink for much of that CO2 by directly absorbing it and becoming more acidic as a result. It looks like it has reached the point where it cannot absorb any more. As for the molluscs which take up carbon for making shells, some of these are now becoming endangered because the pH of the sea makes it harder for them to build shells. This may yet have a catastrophic effect on the food web.

http://www.energy-savingnews.com/2010/0 ... daptation/

Basically, we're killing the oceans too, it's just that most people don't see this or know that it is happening.

[biffvernon]

wonder what stops the ocean creatures sucking all the CO2 up and thereby killing all plant life?

...There is no way that they can 'suck all the CO2 up and thereby kill all plant life'...

The research shows that it is the state of the oceans and their ability to 'deal' with CO2 in the atmosphere that is critical. By 'deal' I've assumed we are talking predominantly about the creation of exoskeletons but I could well be wrong.
...

Why is there 'no way'? I see no mechanism that would limit atmospheric CO2 resource depletion amongst, say trilobites. Should there be an explosion of CO2 using oceanic life it would just be another case of over shoot and die off.

The oceans stop absorbing much CO2 long before the plants die off for lack in the atmosphere. 'Shoot and die off'? Maybe, but feedbacks in a system of dynamic equilibrium is probably a better way to think about it. Sea creatures are sensitive things, worrying about carbon, calcium and temperature but also requiring oxygen and a host of micro-nutrients that all contribute to the mix. Then there's the physical/spatial distributions. If, for example, the dead bits dissolve on the way down before hitting ocean bottom you don't get limestone.

But as UE asked, what's your point?

[clv101]

Why is there 'no way'? I see no mechanism that would limit atmospheric CO2 resource depletion amongst, say trilobites. Should there be an explosion of CO2 using oceanic life it would just be another case of over shoot and die off.

Look up the carbonate and aragonite compensation depth.