Atmospheric CO2 removal technologies?

[mheslep]

The seasonal CO2 ppm swings measured at Mauna Loa are have increased. At the beginning of the record seasonal trough to peak was 4-6 ppm; now it is 6-8 ppm. With the northern hemisphere heavily out weighing the southern in seasonal growth/decay, it appears the biosphere is increasing its seasonal uptake of CO2, which would mean a greater long term lockup of carbon in biomass and soils. I supposed there could be other explanations as well having to do with simple uptake / release of gas from the oceans with temperature changes, that are not balanced north-south.

 

[mheslep]

Increasing CO2 ought to encourage plant growth .

*If* all the many ingredients required for growth are there in sufficient quantity. For instance, that graphic of plant growth states that all were grown with "similar" levels of water, light, etc. But that might mean more than enough water for even the fastest growth scenarios. Suppose instead that the water supply or the nitrogen and phosphorus in the soil were barely sufficient for maximum growth, as it must be in many places, at some CO2 level, say 400 ppm, and no more. Fixing carbon into biomass, as I understand it, requires the hydrogen from water in the presence of certain other required (if not consumed) elements, without (large scale) exception.

 

[jim hardy]

The seasonal CO2 ppm swings measured at Mauna Loa are have increased. At the beginning of the record seasonal trough to peak was 4-6 ppm; now it is 6-8 ppm.

I look at the slope between peaks and conclude Mother Nature still has power in her rate of removal to outpace our rate of addition.
That the amplitude of swings is increasing says we're making her work harder at it, though.

Unforseen consequences are inevitable and if we look closely we might figure out which ones are worth worrying about... i don't at all question the wisdom of doing that.

 

[jim hardy]

Fixing carbon into biomass, as I understand it, requires the hydrogen from water in the presence of certain other required (if not consumed) elements, without (large scale) exception.

well there's plenty of hydrogen in water.

Asimov's 1960-ish essay "Life's Bottleneck" highlighted phosphorous as the rate determining element for the biosphere. He cites upwelling of phosphorous laden seawater near the poles as the reason sea life is so abundant there despite the intense cold.

 

[mheslep]

well there's plenty of hydrogen in water.

Yes, and plenty of places that are on the margin with water. Most of CA probably qualifies the last couple years, so that I doubt plusing up the CO2 there helps growth at all.

 

[Dr. Courtney]

It is usually easier to free Mother Nature than to do her job for her.

Every which growing season? The graph "Recent Monthly Mean CO₂ At Mauna Loa" clearly shows an annual cycle.
I would have expected the CO₂ use to be more or less constant with both hemispheres alternating production.
CO₂ seems to rise during the Northern winter while the Southern Ocean is absorbing CO₂ during the Southern summer. Why?

The growing season in the N hemisphere removes much more CO2 than the growing season in the Southern hemisphere, presumably because there is a lot more land and land-based vegetation takes much more CO2 out until stuff decays in the fall. Not that phytoplankton doesn't consume a _lot_ of CO2 in the oceans, but that the CO2 doesn't last long in the aquatic systems. Most of the aquatic photosynthesis makes carbs that are quickly consumed and move up the food chain with the more rapid release of the CO2.

We've analyzed the annual CO2 variations in the southern part of the southern hemisphere (latitudes -30 to -90), and there is a definite oscillation with the right phase to attribute it to photosynthesis. It is just 5-10 times smaller than the annual oscillation in the northern hemisphere.

One interesting tidbit is that as CO2 levels have been increasing, so has the quantity of CO2 put back into the biomass each growing season. As atmospheric levels of CO2 have increased by 20%, so has the quantity of CO2 taken up by photosynthesis each growing season in the northern hemisphere.

 

[Baluncore]

Sin( x+π ) = – Sin( x ).
So the global annual cycle is the difference between the smaller Southern cycle and the larger Northern cycle.

The long term trend in atmospheric CO₂ will have a slope that varies with the net rate of CO₂ (addition – removal).
It should also have an e^–t curvature determined by any approach to a new photosynthetic equilibrium.
There appears to be no immediate approach to a limit in the long term trend, photosynthetic or elsewise.
If anything the CO₂ is still exponentially increasing as e^+t, with the wrong exponential sign.

If needed, alternative technologies will be selected based on a cost/benefit analysis.
As an economic precaution, we need the widest possible available choice of potential solutions.
The denial of immediate necessity constitutes ignorance of precautionary consideration of potential future alternatives.

 

[Dr. Courtney]

If anything the CO₂ is still exponentially increasing as e^+t, with the wrong exponential sign.

The sky isn't falling, and the increase in atmospheric CO2 is not exponential. The attached graph shows the Mauna Loa data with the best fit exponential, line, and cubic polynomial. The cubic is clearly the best fit, as has been widely recognized in many peer reviewed papers. The exponential is only a slightly better fit than the straight line.

 

[Baluncore]

The sky isn't falling,

Who said it was? Only you.

The point I have made is that atmospheric CO₂ is increasing at an increasing rate.
If there was a significant photosynthetic sink or a natural limit within sight then the slope would be reducing at a reducing rate.
I maintain that there is no evidence yet of a natural upper bulkhead.

By claiming "the sky isn't falling" you are running interference and denying this topic the right to consider potential remedial technologies.

 

[Dr. Courtney]

The point I have made is that atmospheric CO₂ is increasing at an increasing rate.

This is a physics forum. It is important to understand the difference between an exponential increase and "increasing at an increasing rate." Lots of functions that are not exponential can be "increasing at an increasing rate". Positive quadratics are one example. Anyone who knows freshman calculus should be able to give plenty more examples.

If there was a significant photosynthetic sink or a natural limit within sight then the slope would be reducing at a reducing rate.

The photosynthetic sink tends to be short term, because in the current biosphere, most of the CO2 that is used in the growing season is released again within a year by various decay processes.

But as far as scientists can tell, all the CO2 released by the burning of fossil fuels was once in the atmosphere and was added to the natural sink (vegetation that became fossil fuels) by photosynthesis. One wonders if envorironmental or genetic engineering could increase the long term photosynthetic sinks of CO2. If it happened in the past, why can't it happen again?

By claiming "the sky isn't falling" you are running interference and denying this topic the right to consider potential remedial technologies.

Anyone can consider whatever potential remedial technologies they wish. I have denied no one that right. Fraudulent claims that CO2 is increasing exponentially are simply mathematically inaccurate and give deniers ammunition to point how how proponents of certain policies are using inaccurate math.

 

[Baluncore]

The attached graph shows the Mauna Loa data with the best fit exponential, line, and cubic polynomial.

Where is that data from?
What are the equations and coefficients for the linear, exponential and cubic fits?

 

[Dr. Courtney]

The Mauna Loa CO2 data is available from a number of reliable sources. I downloaded the monthly data from the NOAA.

http://www.esrl.noaa.gov/gmd/

 

[Baluncore]

So what were your equations and coefficients?

 

[Dr. Courtney]

So what were your equations and coefficients?

You are welcome to download the data and repeat the analysis if you want these details.

This line of discussion also seems to drift further away from the OP.

 

[Drakkith]

Thread locked for moderation.