Climate change: How could artificial photosynthesis contribute to limiting global warming?
Scientists calculate areas needed for forestation and artificial photosynthesis
After several years during which global emissions at least stagnated, they rose again somewhat in 2017 and 2018. Germany has also clearly missed its climate targets. In order to keep global warming below 2 degrees Celsius, only about 1100 gigatonnes of CO2 may be released into the atmosphere by 2050[1]. And In order to limit global warming to 1.5 degrees, only just under 400 gigatonnes of CO2 may be emitted worldwide. By 2050, emissions will have to fall to zero even. Currently, however, 42 gigatonnes of CO2 are added every year.
Almost all the various scenarios require “negative emissions”
The Intergovernmental Panel on Climate Change (IPCC) has numerically simulated various scenarios. Only in the most optimistic scenario can the climate target still be achieved by means of immediate and drastic measures in all sectors (transport, agriculture, construction, energy, etc.). In the less optimistic scenarios, the global community will have to take additional measures beginning in 2030 or by 2050 at the latest: we will have to implement “negative emissions” by removing large quantities of CO2 from the atmosphere and store them permanently in order to balance the carbon budget. One example of negative emissions is large-scale forestation – forests bind CO2 in wood as long as it is not later used as fuel. But CO2 could also be removed from the atmosphere and bound using artificial photosynthesis.
Physicists have now calculated how this might work. Dr. Matthias May of the HZB Institute for Solar Fuels is an expert in artificial photosynthesis. Dr. Kira Rehfeld is an environmental physicist at the University of Heidelberg studying climate and environmental variability.
Natural photosynthesis: a surface area the size of Europe would have to be forested
In a median scenario, at least 10 gigatonnes of CO2 per year would have to be removed from the atmosphere beginning around 2050 to balance the climate carbon budget. Forestation and cultivation of biomass for reducing CO2 compete for the same areas as are needed for agriculture, however. With just more biomass alone, it is therefore difficult to reach this scale, for natural photosynthesis is not a particularly efficient process. Leaves are able to use a maximum of two per cent of the light for converting CO2 and water into new chemical compounds. The two physicists argue that in order to bind 10 gigatonnes of CO2 per year in the forest, about 10 million square kilometres of the fertile areas on Earth would have to be planted with new forest. This corresponds to the area of continental Europe (up to the Urals!).
With artificial photosynthesis, an area the size of the State of Brandenburg could suffice
Materials systems currently being researched for artificial photosynthesis might bind CO2 with considerably greater efficiency. Already today, on a lab scale, photo-electrochemical systems made of semiconductor materials and oxides can utilise about nineteen per cent of the light to split water, for example, and thus realize part of the photosynthesis process. However, the material system envisaged by May and Rehfeld is not about producing hydrogen with sunlight, but instead about binding CO2 molecules and converting them into stable chemical compounds. „However, this is a relatively similar problem from the point of view of physical chemistry”, says May.
The prerequisite, however, is that it will be possible to develop by 2050 large-scale, durable modules that use solar energy to convert atmospheric CO2 into other compounds. The required area for this solution can be calculated. Assuming efficiency of nineteen per cent and fifty per cent system losses, around 30,000 square-kilometres of modules could be sufficient to extract 10 gigatonnes of CO2 from the atmosphere annually. This corresponds to the approximate area of the German federal State of Brandenburg.
“These kinds of modules could be placed in non-agricultural regions – in deserts, for example. In contrast to plants, they require hardly any water to operate, and their efficiency does not suffer when exposed to intense solar radiation,” explains May. The extracted CO2 could be converted to formic acid, alcohol or oxalate and combined with other compounds (such as calcium chloride) to form solid minerals that can be stored or even used in the form of plastic as a building material.
Focus on development, not on miracles
Even if May and Rehfeld are convinced that such solutions should be considered more closely, they warn against relying on technical miracles. This is because such systems still only function at the smallest scale, are expensive, and not stable in the long term. Changing this requires large investments in research and development.
“It might be possible to develop such modules, but even if we could then build them, we estimate that the conversion will cost at least 65 euros per tonne of CO2. The extraction of 10 gigatonnes of CO2 thus results in costs of 650 billion euros each year. Moreover, negative emissions can only be the last resort to slow dramatic climate developments. The best thing now would be to drastically reduce emissions immediately – that would be safer and much cheaper”, says May.
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HT/David B
From EurekAlert!
Public Release: 16-Jan-2019
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Best approach to the “climate change” problems: stay away and send some money for the tip jar.
https://www.google.com/search?source=hp&ei=bZNCXPriC4rzkwWzh7C4Cg&q=Merkel+climate+change+fund&oq=Merkel+climate+change+fund&gs_l=mobile-gws-wiz-hp.
And let natur do it’s duty – convert CO2 and H20 to C6H12O6 for a greener planet able to feed more people than ever.
If we can just keep the extra CO2 flowing, we will soon have the forests so dense that we cannot get into them and the deserts so small that we can walk across them.
You cannot reduce global temperature by limiting something that didn’t cause it in the first place
The bathtub us too simple. It does not reflect natural feedbacks to increasing temperature, which deserve their own input spigot. For whatever reason the planet is currently warming, a warming ocean will sink a bit less, and warming soils will add a lot more to the atmosphere.
The surface tension of the ocean surface filters (fractionates) isotopes both in and out, with heavier isotopes being rejected both ways, but more stringently on outgassing. Ocean total flux is enormous, approaching 100Gt moving annually both ways, but since outgassing fractionation is 5x more stringent, ocean flux still nets light Carbon to the atmosphere at about -8 PDB. This -8 happens to be the current atmospheric ratio.
Soils are essentially a one way carbon input to the atmosphere, just like humans. Soils kick in 60Gt annually; humans 10. Soils -21 PDB to the atmosphere; humans -24. Soil respiration increase with temperature is pretty linear and amounts to about a 5% increase per degree C. The reputed 1 degree warming is thus good for 3 extra Gt annually from soils.
But the net result is that the biosphere is absorbing CO2, and not emitting.
You are quoting the alarmist mantra about the permafrost.
This is the confusion. Does your biosphere include humans? Of course the Carbon based biosphere on a Carbon starved planet is a net sink for both mineral and biological Carbon. This is trivial. If the question is framed, “where does the atmospheric Carbon come from?”; simply stating that the biosphere is a net sink is not helpful. We are talking about the atmosphere, not the biosphere.
Human cumbustion and soil respiration are unusual in being essentially one way additions to the atmosphere with very similar isotopic ratios. They are both biological in my world. Volcanoes are a mineral source with vaiable isotopic ratios. Weathering is a mineral sink subject to chemical fractionation and will leave heavier 13C in the atmosphere.
I am certainly not quoting any mantra about permafrost.
Gordon,
Have you prepared a Keeling plot (δ13C vs 1/CO2) or a 13C-CO2 balance calculation? Without any data analysis, it is not possible to evaluate your position.
“Soils -21 PDB to the atmosphere; humans -24.”
And yet the observed decline in atmospheric 13C/12C tells us that on average the δ13C content of the incremental atmospheric CO2 is -13 per mil (PDB). Do you agree? Have you prepared a Keeling plot (δ13C vs 1/CO2) or a 13C-CO2 balance calculation? If so, please share.
“Soils are essentially a one way carbon input to the atmosphere”
In that case how come there is such a lot of carbon in the soil? Modern-type soils have existed since the Devonian. They should have lost all carbn long, long ago.
Global oligarchy and massive money transfers from the poor to this ruling class is the only solution they accept.
CO2 cycle of the climate system sets to a new balance all the time taking into account all changes in sources and sinks. Satellites tell that sources are rain-forests and China. https://www.scientificamerican.com/article/first-maps-from-carbon-monitoring-satellite-show-global-co2-levels/.
More vegetation and less concrete is fine for me.
Besides being piss yellow, the tub is simplified to deceptive levels.
And the cure offered is yet more climate fiction posed as science.
Another boring, unoriginal, derivative, deceptive climate paper.
Natural sinks increase proportional to atmospheric level, models assume sink saturation which is not observed.
OK- extract C & O from the air and turn it into organic chemicals without using h2o. Good idea.
a) If not from h20, where’s the H come from?
2] Whatcha gunna do wit da end products?
Maybe they could, using the same bathtub pic, explain the mechanism that, to warm the water in your bath, you should warm the air in your bathroom. After all, THAT is what the AGW-crowd believes.
The bathtub model could prb’ly do at least as good as the current “models”, and save a bundle of money and time. In keeping w/the modeller-PCism, use a range of different bathtub designs (a different one for each participating country so nobody feels left out) and then average the results.
Then hope there isn’t a leftover “ring-around-the-bathtub”.
“These kinds of modules could be placed in non-agricultural regions – in deserts, for example. In contrast to plants, they require hardly any water to operate, and their efficiency does not suffer when exposed to intense solar radiation,” explains May.
Another stupid conjecture from Mr May Maybe. Photosynthesis requires six mols of water and carbondioxide each to get one mol of sugar.
In deserts water as humidity is scarier than CO2. Of course logic is much more scarier in these folks.
Oh my!! – scarcier
Even simpler is a concreter’s pan filed with water & lying in the sun which I saw in NYC 40 years ago. The dirty water welled up & down in short time intervals, and that told you all you needed to know about El Ninos and La Ninas.
We have probably all seen some big ideas on either ameliorating the effects of “carbon” emissions or for pulling C02 from the atmosphere. These ideas go nowhere because the actual intent of those propagating “climate change” propaganda are not interested any stopping any alleged global warming. They want humanity to stop using fossil fuels altogether and to create a world government. They want to replace capitalism and freedom with socialism and serfdom.
An important point in the diagram is that the sources are at different locations to the sinks. In a Berne model where CO2 is “well mixed” then this makes no difference. But it is clearly wrong. A kilogram of fossil fuels burnt in the summer Sahara dessert, or an equatorial rain forest, or a winter storm in the Antarctic oceans will have very different fate.
The question is, “How wrong is it?”
A follow-up paper to the last Levine paper (in 2013 I think), should tell us lot, but seems overdue. I can’t find any published data yet. At about that time, the simple approximate first-order decline in excess 14C from the bomb-spike (as measured at Jungfraujoch and Schauinsland) was approaching zero (I refer to the chemical equilibration, not a decline due to radio-active 14C decay).
That was thus the time when the consensus thinking indicates 14C would have fallen back to the levels observed before human bomb-tests in the atmosphere produced a spike in 14C levels, and Levine’s paper showed that. But subsequently, the annual addition of ~3% of “cold” CO2 from fossil fuel sources should produce a commensurate decline in the levels of atmospheric 14C below the levels observed before human intervention. That is, unless the increase in atmospheric CO2 came from non-fossil fuel sources such as deforestation, other land use changes, or ocean degassing) which contain ambient levels 14C, thus producing little change in atmospheric 14C ratios.
This should be a wonderful piece of data to show that the Berne model has either passed a significant test, or that it is holed below the waterline. Most likely, I would bet that it shows something in between. That is the way the data tends to go in the real universe. But the longer I don’t see this data being published, the more my suspicions will grow. If any one has that data, I would love to see it.
I recently read an article that concludes worldwide greenery has increased 14% due to the increase CO2 in atmosphere. That surely makes sense to me as a Chemical Engineer, and also as the product of a farm where we saw huge increases in wheat and corn yields, coincidentally(?) as CO2 increased. Surely makes sense to me, when you increase reactant concentrations, yields go up. Why is this fact-of-life routinely ignored by “climate scientists”?
Genetically engineered plant life will more efficiently absorb CO2 in the near future. Decreasing CO2 levels, starving plant life and endangering the planet, will be the next crisis for idiot globalists.
I can sum up all of these comments for everyone,
It’s a stupid idea.
EureakAlert! Just slinging hot garbage left and right.