Sunday, 9 November 2014

Letter to my Cousin whose name is program...

Dear Cousin 

Karkun Ukko
I am pleased that the quote [*] from the book of Lin Yutang, “The Importance of Living” has you found your interest. Admittedly, it may contain some "strong stuff", for some fundamentalists at least. 

As you might know, the German translation of his book had moved with me since the time when I, still a teenager, had 'rescued' it from the library of my parents.

The sections about growing up that appealed most to me then and now [#]: "... but there comes a moment where the pagan looks at the perhaps warmer and cheerful Christian world with a feeling that it is also childish, as I want almost say, is less mature. You may have a more colourful and beautiful look, but it is precisely for this reason not so true and therefore in a sense of lesser value. The truth has to have a certain price to be worth, and you must not hesitate to take its consequences on yourselves ... ".

You refer to thoughts in the last sections of the quotation in which Lin Yutang "ousted" himself as a religious person: "…the Chinese pagan [is] ... honest enough to let the creator of things in an orbit of mystery, wherein his sense of awe and shy reverence is expressed. With this feeling, he is content. The beauty of the universe, the incredible artwork of countless things of creation, the mystery of the starry world, the grandeur of the heavens, the dignity of the human heart - that is all the Chinese heathen quite present. But again, he is content. He takes the death back and also the pain and suffering, and he weighs up against the gift of life, the fresh farmwind and the clear mountain moon - and he finds nothing to complain. To bow to the will of heaven, he appears as a truly religious, awesome attitude ... that is all what he requires. ... ".

Drawing by Escher
Lin Yutang reflects transcendentally; thus he reflects in a religious manner. He refers to what in turn you call cautiously as "something" (as "something" that helps us humans to survive). However, you theist cannot do different, a few lines further in your essay, but to deify that "something" by letting "it" live somewhere. You're a theist!

Regarding your excursus into the wickedness of the world, I let you do that today without entering into debating that misanthropic view. The issues of "cui bono" (who benefits from this?) can be tackled elsewhere. This particular worldly finesse of religious (Christian) ideas, e.g. about God's justification and consolidation of earthly powers, had been dealt with at a different time already [1] and "political" consequences were discussed also.

Back to Lin Yutang; a non-theistic Lin Yutang would write something like the following when ousting him: "... the Chinese pagan ... he is content ... [with the] mystery of the world of stars, ... , [the] dignity of the human heart - that all is quite present to the Chinese pagan. But again, he is content. He takes the death and also the pain and suffering, and he weighs up against the gift of life, the fresh farmwind and the clear mountain moon - and he finds nothing to complain ... that is all what he requires. ... ".

It remains for now to touch the question why we humans are so easily to be fascinated by something "supernatural"? Why is it difficult for many to find a non-theistic world-view satisfying. Research, cognitive science of religion into the development (evolution) of religious impulses, ideas and behaviours provides a first insight; in a "nutshell":

Images illustrating early, "primitive" religious concepts 
The modular architecture of the human mind and especially the human capacity to understand other "agents" to whom beliefs and desires are attributed, is the basis of the notions of "supernatural agents". Likewise, social insights (cultures) emerge in which supernatural agents as interested part of social life are postulated. These beliefs are products of biological and cultural evolution. Evolution favoured the "supernatural actors" to a degree that people across cultures use such concepts in an intuitive and automatic way. The mental reaction is automated and thus is similar to the mechanism "that two points and a straight line automatically trigger the idea of a face".

The human mind is composed of a plurality of such modular mechanisms, so certain "types of spiritual convictions" have a selective advantage over others. These "types of spiritual convictions" are accepted with more ease because they were reflecting a kind of "natural" ("primitive") thinking. Abstract theological concepts are elaborate versions of initially simple but contagious "spiritual" people's ideas, which have developed to costly constructs. And in turn, atheistic concepts are recent and costly de-constructions of both, of these simple "spiritual" people's ideas and their elaborate further developments in the world religions.

Ukko El'Hob

see German version of the quote at; [#] My translation back into English; [1]

Thursday, 7 August 2014

One Ocean, One Index – an Essay on Opportunities and Limits

The ocean is beneficial for societal wealth and human development. The oceans offer access to food, materials, energy, and recreational opportunities. Many states take (and took) initiatives to master their access to marine resources; now often under a “blue” catch-word [a]: “The 'Blue Economy' concept has attracted much interest in international fora and become a key to development strategies of international organizations. This cross-cutting initiative aims to provide global, regional and national impact to increase food security, improve nutrition, reduce poverty of coastal and riparian communities and support sustainable management of aquatic resources.”

It is likely that seas and oceans, even more than today, will be a theatre of competing economic interests. Already today, the convenient availability of ocean resources has put high pressures on the health of the ocean, e.g.: overfishing shifts balances of ecosystems, pollution trough extraction industries threats regional seas, marine litter spoils recreation, plastic threatens marine life along the entire food chain, or alterations of coastal zones destroy unique habitats. The risk is high that these pressures increase when more “blue economy strategies” get implemented. In that context, an index to describe the overall ‘health of the ocean’ in a standardized manner would be much needed and could be a very useful management tool.

Drawing on experiences in coastal zone management, comprehensive assessments are emerging, which consider a composite of oceanic features that influence societal wealth and human development. The wealth of marine information that is available nowadays through a multitude of studies may be incomplete, but a tentative assessment of global ocean-health issues is possible. Against this backdrop, proposing comprehensive ocean-health index [1] and making it available [b] was a very important step forward towards a sustainable human use of the ocean; although some may consider this step as “bold” or even “too bold”.

Ten amalgamated assets

The ocean-health index amalgamates ten societal assets [c] undertaking one composite assessment of reference values, current status and future status. The ten assets were selected to cover a wide range of ecological, social, and economic benefits for a wide range of “use cases”. The score of the ocean-health index, a single number, shall describe the state of the human-ocean system as a composite-asset. The main assumption, implicit to the index, is that a combination of the ten assets should be preserved for any healthy human-ocean system, although the combination may vary regionally and in time.

The ocean-health index is presented annually at country/regional level and at global level. For 2012 and 2013, the score of the ocean-health index was estimated to be a modest 65 of 100 when averaged at the global level. The score of individuate countries varies between 41 and 94; and countries of very different natural and economic setting have the same score like Norway and Netherlands (74) compared to Iceland that scores 58.

The score for the ocean-health index is calculated as the weighted arithmetical average of the scores for the ten assets on which the index is built. Selecting these assets, identifying indicators describing them, gathering data measuring the indicators is a tedious and complex undertaking, which in itself gives ample space for biases, nuanced choices or simple errors. Improving the ocean-health index is subject of research and study that, by no means, renders the index meaningless, because it provides a means for global benchmarking and comparison that otherwise would be missing.

Compared to addressing possible defects “of substance” of the ocean-health index, it seems ‘picky’ to question the use of a “weighted arithmetical average” to calculate the score of the ocean-health index. Nevertheless that was done recently [2], for very good reasons, and with lessons that may serve as examples also for other index that calculate a score for a set of assets.

An innocent average ?

The mathematics of a “weighted arithmetical average” that is used to calculate the ocean-health index looks innocent and non-problematic.

An “arithmetical average” of single marks gives each mark the same impact on the composite mark. That makes good sense if a feature is marked several times, a set of measurements, a sample, is obtained, and thus the elements in the sample are belonging to the same kind but vary randomly. Using weights is a simple and transparent approach to set preferences between marks for features of similar kind, i.e. to account for some non-random variation within a sample of “features of about the same kind”.

Thus, in face of the intrinsic complexity to assess in a composite context the different assets that are underpinning the ocean-health index, taking an approach of “one asset one vote”, i.e. arithmetical average, looks like a fair, “democratic” first choice. Furthermore, giving different assets different weights looks like a fair option to reflect social or political choices without excluding a “minority asset”. Nevertheless, just these simple first-hand choices are not innocent but set a rather radical “normative frame” [2] for managing a set of “assets” by means of a index, which may limit the usefulness of the index.

Using an “arithmetical average” to obtain a score for a set of assets implies a paramount assumption, namely that “unlimited substitution possibilities” exist among these assets to obtain the same score. In that context, “substitution” means that under-performance for one asset can be balanced by better-performance for another asset; “unlimited” means that under-performance for one asset is not limited by a lower boundary; and “possibility” means that better-performance for any asset may balance under-performance of any asset. These assumptions are quite radical, indeed.

Using a “weighted arithmetical average” does not alter the assumption, although it modifies the “cost” of the substitution; i.e. performance for an asset with low weight has to improve much to balance a minor drop of performance of an asset with a high weight.

A radical “normative frame” ?

To perceive how radical is the assumption of “unlimited substitution possibilities among various assets”, one may assume: (1) a shopping list of ten items for the dinner table, (2) getting these items in different quality or quantity, but so that (3) the average quality of the dinner is the same. Evidently, a good starter may make good for a bad desert, or a good wine (or beer) compensates for…; but “unlimited substitution possibilities among the various parts of the dinner”? Common sense tells that this may work, indeed, but at best for a “below-standard dinner”.

from: MARUM - Center for Marine Environmental Sciences
(distributed via
Evidently, “unlimited substitution possibilities among various assets” is a framework for “a manager’s dream”. Such a framework maximises the number of operational alternatives to amalgamate assets although respecting social choices of different assets through their weighting.

However, “unlimited substitution possibilities among various assets” is an exceptional case. It is ”the real-world’s manager’s headache” that amalgamating assets is limited by the substitution potential among them. The substitution potential may be limited for ecological, technical or social preferences. Considering the ten single assets that are amalgamated into the ocean-health index, it seems possible that they substitute each other to some degree, but it is very problematic management guidance to assume that they substitute each other fully.

Strong or weak sustainability ?

Extremes in degree of substitution possibilities between assets is summarized in two alternative concepts, of either “strong sustainability” or “weak sustainability”. The former requires keeping all assets above critical levels, thus avoiding any substitution between them. Under the concept of “weak sustainability” substitution between assets is unconstrained and can be done without any limits.

That latter concept of “unconstrained substitution” is applied for the ocean-health index by the choice of the mathematical formulation how the average score of the ocean-health index is calculated [2]; namely using a weighted arithmetic mean.

The assumption, which is implicit to the mathematics, namely “unconstrained or unlimited substitution”, is unrealistic and may misled. However, it goes without saying that experienced managers of marine resources would be aware of limitations to substitution of assets, although implementing that awareness for a set of assets in a competitive environment is not only an intellectual challenge.

Border between open sea water and a plum
from the Mzymta river (Sochi, Russia)

from: Alexander Polukhin
 (distributed via
Obviously, intermediate levels of substitution may be achieved for many real-world situations and their description by means of an index. And evidently, for many real-world situations it will be difficult to determine “what are boundaries to substitution?” Manifestly, any intermediate level of substitution for assets underpinning the ocean-health index will depend on the specific ecological-human intersections of the respective human-ocean system. Whatever is obvious, evident or manifest, it will be hard and tedious work to narrow the range of substitution possibilities, and in some circumstances “strong sustainability” should be applied to guide management choices, simply.

The mathematics to describe “intermediate levels of substitution” are available. Likewise the tools are available to study implications of having chosen a specific mathematical method to describe “intermediate levels of substitution”. They are used, for example, in social choice theory [d]. Aggregation of individual asset with constraint or limited substitution into a composite scores can be described using ‘generalized averages’ [e]; with arithmetic, geometric or harmonic average as special cases of the ‘generalized averages’.

Composite averaging procedures and intermediate level of substitution

Choices of limited substitution possibilities for the various assets of the ocean-health index can be made [2] applying state of the art knowledge on natural resources and ecosystem assessment, which are reflecting the state of the human-ocean system, and using appropriate mathematics, i.e. specific functional forms (“functions of functions”) [f].

The mathematics for calculating the index can get increasingly composite by working in a nested manner, using generalized means, applying variable setting of substitution with constraints on the overall score for the less-performing assets, and fixing “hard” lower boundaries.

Evidently, such kind of “composite averaging procedure” lacks the simplicity of the arithmetical average. The “composite averaging procedure” is more like an elaborated model of the substitution possibilities, which has to be analysed with care; not only for his non-linear behaviour.

Notwithstanding the complexity, such a model could capture our best understanding of the functioning of the ocean-human intersections though appropriate mathematics. As such it may be a very useful research tool.

However, the complexity of the model may be considered as much too high to abandon the “weighted arithmetical average” because of its relative transparency for many users. Thus for management environments the “weighted arithmetical average” may be preferred.

Ocean-health index with intermediate level of substitution

Recalculating the ocean-heath index with a modified methodology to calculate the average score [2], showed a considerable dependence of the ocean-health index on the choices for the substitution possibilities including substantial swings of countries between camps of “well-performing countries” and “under-performing countries”.

The English Channel in Cap Blanc-Nez; 
above the two ships a brown pollution layer; 
probably containing NO2 and aerosols.
from: Alexis Merlaud (distributed via
The bulk result of the study [2] is that the global ocean-health index decreases by 20%; namely from a score of 65 of 100 to the score of 52 of 100 if the “weighted arithmetical average” is replaced by a revised methodology limiting substitution among assets. The revised index reduces less-realistic possibilities for offsetting poorer performances in certain assets by better performances in other assets. The drop of the global ocean-health index is important, and possibly many decision makers, who would find a score of 65 of 100 “still tolerable” - two good for one bad -, would modify that view for a score of 52 of 100.

Even more striking is the finding [2]:“...when we turn to the assessment of individual countries. Countries with an unbalanced performance across the assets significantly deteriorate in the ranking compared to countries with a balanced performance. For example, Russia and Greenland fall in the ranking for 2013 by about 107 and 118 places (out of 220) respectively, while Indonesia and Peru improve by about 78 and 88 places respectively.” Similar striking changes are observed regarding the assessment of change over time, for one out of four countries the direction of change is inverted.

What is the lesson to draw?

Th ocean-health index is useful because of the limitations of choices that were made when designing it. The challenge to describe a set of assets through a single index drives insights into the human-ecological intersections of the human-ocean system, including the issue of appropriate mathematical description.

A first insight to keep:

Setting up an ocean-health index [1] was a very relevant endeavour, and is a lasting contribution to the management of the human-ocean system. An ocean-health index could be a tool for comparison of national and regional policies, benchmarking, and qualification of development options, which is much needed to manage global commons like the ocean. Implications of the (simple) mathematics to calculate the ocean-health index have been analysed [2].

The result of the study indicates that the mathematical method chosen for calculating the average is causing bias of the index. The method to calculate the score of the index by “weighted arithmetical average”, makes the index insensitivity to less-appropriate choices to substitute assets for which performance is low by better-performing assets. This feature of the index limits the use of index. The possibility of unconstrained mutual substitution between assets within the composite score requires adjustment. Without such adjustment [2]: “policy assessment and advice based on an index with unlimited substitution possibilities could result in (a) certifying a healthy human-ocean system for countries that in reality neglect important aspects of ocean-health and (b) identifying development trajectories as sustainable although this is actually not the case.”

A second insight to keep:

The assessment of the various oceanic features relevant for societal wealth and human development is improved, if substitution possibilities among different assets are constrained. Evidently, the substitution of different assets is a societal endeavour. It requires knowledge, social choices and norms and particular the latter may evolve and vary among societies.

Nevertheless, any substitution possibility should be limited and confined by boundaries of the elasticity of the ocean system, if we know the ‘elasticity’ otherwise the “strong sustainability concept” or the “precautionary principle” should be applied. For being practical, the retained substitution possibilities should provide for some elasticity to have a margin for management decisions - not everything goes, not all is forbidden – to render the ocean-health index a tool with operational value.

A third insight to keep:

Furthering the analysis of suitable substitution of assets and how to describe the substitution process in mathematical terms is needed to properly evaluate benefits, risks and development options of the ocean-human system.

For the best or the worth, a common and robust ocean-health index is a much welcomed management tool, and possibly the ocean-health index will be part of any mature ‘blue economy strategy’. Thus, it is important to design the index in a manner that is sound and practical. The alternative would be to manage all assets one-by-one using the “strong sustainability concept”, what possibly would end in a political process to retain on a case-by-case only those assets that are considered most relevant. In that situation any comparison of national and regional policies, benchmarking, and qualification of development options would be far more difficult.

Thus, one composite index has a strong appeal. However, attention should be given to the complexity of the averaging procedure, which if too complex or perceived as too complex would hamper application of the index. To recall, the attractiveness of calculating the ocean-health index by a weighted arithmetical average is the simplicity of the procedure that is understandable for many.

Possibly a two tiers approach may provide a useful compromise. Tentatively, such a compromise could be: (i) apply the “strong sustainability concept” to identify assets that either match this concept or fail, (ii) calculate the score of the ocean-health index for both subsets, (iii) calculate the arithmetical average of both sub-scores (weighted by the number of assets in each set) to get the score of the ocean-health index, and (iv) present this score with the scores for the sub-indexes as lower and upper bound.

Post Scriptum:

How to generalize this experience? What has been discussed above for the ocean-health index applies "mutatis mutandis" to any index that gives an average composite score of several assets that can substitute each other only partially.

Ukko El'Hob

[c] The single assets of the ocean-health index are: (1) Artisanal Fishing Opportunities, (2) Biodiversity i.e. species and habitats, (3) Coastal Protection, (4) Carbon Storage, (5) Clean Waters, (6) Food Provision i.e. fisheries and aquaculture, (7) Coastal Livelihoods & Coastal Economics, (8) Natural Products, (9) Sense of Place i.e. iconic species’ and special places, and (10) Tourism & Recreation [x].

[1] An index to assess the health and benefits of the global ocean (2012). Benjamin S. Halpern, Catherine Longo, Darren Hardy, Karen L. McLeod, Jameal F. Samhouri, Steven K. Katona, Kristin Kleisner, Sarah E. Lester, Jennifer O’Leary, Marla Ranelletti, Andrew A. Rosenberg, Courtney Scarborough, Elizabeth R. Selig, Benjamin D. Best, Daniel R. Brumbaugh, F. Stuart Chapin, Larry B. Crowder, Kendra L. Daly, Scott C. Doney, Cristiane Elfes, Michael J. Fogarty, Steven D. Gaines, Kelsey I. Jacobsen, Leah Bunce Karrer, Heather M. Leslie et al., Nature 488. doi:10.1038/nature11397

[2] How healthy is the human-ocean system? (2014). Wilfried Rickels, Martin F Quaas and Martin Visbeck. Environmental Research Letters Vol. 9(4). doi:10.1088/1748-9326/9/4/044013

Tuesday, 18 March 2014

Keep Oxygen, Dump Carbon

Take a breath! Get your regular intake of oxygen and smoothly expel a whiff of carbon dioxide. The concentration of carbon dioxide in Earth's atmosphere is rising. In turn, the concentration of oxygen drops a tiny bit.

Oxygen, flat and stable...

Combustion of oxygen by fossil fuels makes up for about 3% of the total amount of oxygen that annually is drawn from the atmosphere. Respiration of plants or animals and microbial oxidation consume much more oxygen than the burning of fossil fuels. The atmospheric reservoir of oxygen would sustain respiration for about 5500 years. That is a very long time on a human time-scale but on a geological timescale that is a very short time. Thus taking a geological view, oxygen in the atmosphere is sustained by the biosphere in the same manner as the biosphere sustains the concentration of carbon dioxide. Photosynthesis steadily replenishes oxygen, and it consumes carbon-dioxide and balances oxygen consumption and carbon-dioxide replenishment. A little less than half of the total oxygen production occurs in the surface waters of the ocean. These waters frequently are over-saturated with oxygen, be it by photosynthesis or air bubbles due to wave breaking.

Terraced fields in Yunnan Provice (China) 
Credit: Hongkai Gao (
Since half a Billion years, the marine and terrestrial biosphere keeps the Earth vigorously oxygenated. Contrary to the amount of atmospheric carbon dioxide, the amount of oxygen in the modern atmosphere is far too high that burning of coal, oil and gas since the start of the industrial revolution may have had a noticeable effect on it. The biosphere is exchanging oxygen with the atmosphere and the ocean. The amount of oxygen in the ocean is about a hundred times smaller than the amount of oxygen in the atmosphere. Most of the oxygen on Earth is bound in the rocks of the lithosphere. The lithosphere contains hundred times more oxygen than the atmosphere. Just as for carbon, oxygen mainly is stored in the lithosphere.

Weathering of rocks on the continent would consume the oxygen in the atmosphere in about 20 Million years. That indeed is a very long time on a human time-scale, but on a geological time-scale it is a short time. The weathering of rocks leads to oxygen-enriched minerals that are washed into the sea. The minerals get buried in marine sediments for very long periods. Finally, they are incorporated into the crust of the Earth, which slowly gets richer in oxides. Some of these oxides will be recycled through plate-tectonics, subduction and volcanism into the atmosphere.

It took three Billion years to reach the current level of oxygen concentration in the atmosphere and the ocean. Eventually, a vast reservoir of free molecular oxygen had formed. In essence, on Earth only the dead matter in the biosphere is left to consume the oxygen that is produced by photosynthesis.

Carbon, down...

To accumulate oxygen in the atmosphere, vast amounts of carbon have been deposited into the Earth's crust, be it a bit of coal, carbon rich shale or limestone. That in turn leaves the reservoir of carbon in the atmosphere and the ocean sensitive to a vigorous biosphere or active humans.

Taïga burning near Krasnoiarsk

Credit: Jean-Daniel Paris (
The ocean buffers fluctuations of carbon concentrations in the atmosphere, also the anthropogenic increase of carbon dioxide. So far the ocean has taken up a substantial share of the carbon dioxide that was added to the atmosphere by human economic activity. The anthropogenic increase of carbon-dioxide concentration in the atmosphere is only half of what should have happened because of the amount of fossil fuels burned since the beginning of the industrial revolution. The ocean absorbed the other half of the carbon exhausted by burning fossil fuels. The carbon dioxide capture in the sea-water currently shifts acidity of the ocean.

The absorption of carbon-dioxide in the ocean leads to the formation of carbonic acid in the surface waters of the ocean and to increased dissolution of carbonates. That in turn is changing the life for species with an external carbonate skeleton, be it coral, algae or shellfish. Some worry that this change will impinge negatively on the amount of photosynthesis in the ocean.

Ukko El'Hob
This text together with the two related texts were inspired by the article “The rise of oxygen in Earth's early ocean and atmosphere” by Timothy W. Lyons, Christopher T. Reinhard and Noah J. Planavsky, which was published in February 2014 in Nature. Many insights are taken from “The global oxygen cycle “ by S.T. Petsch, which was published 2003 by Elsevier in volume 8 of in the “Treatise on Geochemistry” (Editor: William H. Schlesinger. Executive Editors: Heinrich D. Holland and Karl K. Turekian). Any inconsistency, error or slanted statement is responsibility of the author.

Oxygen and the Culprit

Take a breath! Get your regular intake of oxygen and smoothly expel a whiff of carbon dioxide. The concentration of carbon dioxide in Earth's atmosphere is rising. In turn, the concentration of oxygen drops a tiny bit 

Oxygen, high and stable.

Nowadays we live in an oxygen rich world, and we take that for granted. A fifth of Earth's atmosphere is free molecular oxygen. This is a large reservoir of oxygen, which has not been altered much by the burning of fossil fuels. The waters of the world ocean are oxygenated down to the greatest depths. Oxygen concentration in the deep sea is sufficient to sustain animal life at the bottom of the deep sea.

Oxygen in the sea water is consumed by organic matter that is precipitating from the surface waters of the ocean. The oxygen minimum in the ocean is located at mid-depth. Oxygen is transported into the depth of the sea by lateral advection of oxygen rich waters. Both processes, the vertical precipitation of oxygen-consuming matter and the lateral advection of oxygen balance at mid-depth.

The sunrise - Romanian Black Sea Coast
Credit: Gerrit de Rooij (
The current global configuration of continents favours the oxygenation of the deep sea through slowly global overturning of water masses. Oxygen rich waters form at the surface of sub-polar seas. These waters sink to the bottom and spread into the world ocean. Finally, the waters well up at a place far away from their origin. Upwelling waters at mid-depth along the American east-coast are among the waters with the lowest concentration of oxygen. The ventilation shafts of the modern ocean are located in the sup-polar North Atlantic Ocean and the circumpolar Antarctic Ocean.

Apart from the general global pattern, today oxygen is absent in some parts of the global ocean only. Currently, the deeper layers of the Black Sea are free of oxygen because of the large inflow of terrestrial organic matter. Likewise, the bottom waters of some highly eutrophic coastal zones and waters close to hydrothermal vents are free of oxygen. In these waters, hydrogen-sulphur molecules (mainly hydrogen sulphide) are found instead of oxygen. Hydrogen-sulphide is toxic for oxygen-breathing life-forms. Ancient life-forms exist that dwell on hydrogen-sulphide. These life-forms are survivor of life-forms that populated Earth before photosynthesis started. Oxygen is toxic for these life-forms.

Oxygen, getting up and rise…

Since two Billion years, a substantial amount of free oxygen is found in the atmosphere and the ocean. Oxygen level increased first in the atmosphere and much later in the global ocean. However, free oxygen was very rare in the first half of Earth's history. The lasting switch from an oxygen-poor environment to the oxygenated environment happened two billion years ago. That event got named the "Great Oxidation Event".
...somewhere in Iran
Credit: Amirhossein Mojtahedzadeh (
Its geological marker are the first occurrence of reddish soils and disappearance of easily oxidized minerals in ancient stream beds. However the naming convention "Great Oxidation Event" seems misleading: the switch from an oxygen poor Earth to an oxygen rich Earth was more like a very long take-over battle than a rapid move.

Three Billion years before present, change had started. The atmosphere contained at least a very tiny amount free oxygen. However no oxygenation of the Earth had occurred yet. It possibly has taken one Billion years more to establish in the atmosphere a stable, albeit low level of free oxygen (< 1%). Then it took another Billion years to oxygenate the ocean and to push the concentration of oxygen in the atmosphere up to contemporary values of 21%.


The culprit: New life...

Colonization by lichens
Credit: Antonio Jordán (
There are forms of photosynthesis that do not produce oxygen as by-product. Only oxygenic photosynthesis is the sources of free oxygen. Oxygenation of the Earth developed with the evolution of the photosynthetic metabolism. Photosynthetic life-forms were the driver turning the switch to an oxygenated Earth. Algae and bacteria (prokaryote and eukaryote) living in the sea or at its shores were the culprits providing whiffs of oxygen. These algae and bacteria evolved from earlier life-forms using non-photosynthetic metabolisms and that were dwelling, for example, on hydrogen-sulphide. Today such life-forms still exist. They stay shut-in in peculiar environments because oxygen is toxic for them in the same manner as hydrogen-sulphide is toxic for photosynthetic life-forms.

For about two billion years the early life-forms of photosynthetic algae and bacteria survived in a hostile marine environment rich of hydrogen-sulphide. That long time span was needed that effective photosynthesis metabolisms evolved and oxygenation of the global ocean occurred. In that long period, sometimes called by earth scientists the "boring Billion", profound changes of Earth's geology and geochemistry occurred also.

Likely these changes helped establishing the geochemical cycles that keep free molecular oxygen in the atmosphere and the ocean at high levels: Hydrogen escaped into space. Volcanism occurred on land, easing that freshly vented hydrogen escaped into space. Tectonic reorganization of the continental plates modified the layout of the sea. Consequently circulation of water masses in the global ocean changed. Sedimentation basins opened and closed. Burial of organic-carbon in limestone and shale prevented rapid recycling of oxygen. Methane and iron pyrites got oxidized in the atmosphere and ocean, and the Earth's crust was enriched with oxidized minerals. Redox-sensitive trace-elements (chromium, molybdenum, manganese) got buried in the sediments.

Ukko El'Hob

This text together with the two related texts were inspired by the article “The rise of oxygen in Earth's early ocean and atmosphere” by Timothy W. Lyons, Christopher T. Reinhard and Noah J. Planavsky, which was published in February 2014 in Nature. Many insights are taken from “The global oxygen cycle “ by S.T. Petsch, which was published 2003 by Elsevier in volume 8 of in the “Treatise on Geochemistry” (Editor: William H. Schlesinger. Executive Editors: Heinrich D. Holland and Karl K. Turekian). Any inconsistency, error or slanted statement is responsibility of the author.

Monday, 17 March 2014

Two Plays a Billion Years apart

Take a breath! Get your regular intake of oxygen and smoothly expel a whiff of carbon dioxide: The concentration of carbon dioxide in Earth's atmosphere is rising. In turn, the concentration of oxygen drops a tiny bit.

Currently, each year human economic activity converts fossil carbon into 7 Gigatons of carbon dioxide. Burning coal, oil and gas consumes oxygen and exhausts carbon dioxide. The amount of carbon dioxide exhausted each year adds up to about 1% of the carbon stockpiled in the atmosphere. That steady input of carbon keeps anthropogenic global change going.

Peaty soil in the Andean highland (Ecuador)
Credit: Martin Mergili (
How dramatically the current play of anthropogenic global change enfolds, that play is nothing compared to the play that had enfolded long time ago when oxygen got released into the environment. Some Billion years ago, the oxygen-producing photosynthesising life battle to master the world. 

Let's look at both plays, the ancient and the modern!  


Carbon, thumps up!

Most remarkably, since the industrial revolution set off two centuries ago the concentration of carbon dioxide in the atmosphere increased by 40%. Much of the carbon exhausted by human economic activity got neither absorbed in the biosphere or got stored in the deep ocean. The deep ocean is the main reservoir of carbon on Earth that could be recycled rapidly.

A black smoker in 3,000 meters depth
at the Mid-Atlantic Ridge.

Credit: MARUM - Center for Marine Environmental
Sciences (
In well less than a decade the biosphere would consume the total carbon-dioxide in the atmosphere through photosynthesis. A further decade would be needed to consume the carbon in the surface layer of the ocean. About three-hundred years would be needed to consume the carbon stored in the deep ocean. For humans, that is an elapse of time but for geological processes this is an extremely short period.

Respiration and microbial oxidation together are of a very similar strength than photosynthesis. Jointly these processes recycle rapidly the carbon that is available in the atmosphere. Recycling of the carbon stored in the ocean is a bit slower.

The annual anthropogenic input of carbon-dioxide into the atmosphere is several times bigger than the annual imbalance between photosynthesis, respiration and microbial oxidation. This makes the anthropogenic input of carbon into the atmosphere such a strong driver of change.

Oxygen, thumps up !

Redox processes causing a pattern of
red to greyish green mottles in a
Regosol, Ria Formosa, Portugal
Credit: Antonio Jordán (
Roughly two-and-half billion years ago, a different gas than carbon dioxide was driving global change. Free oxygen - two oxygen atoms binding in an oxygen molecule – caused troubles. Oxygen was exhausted into the environment by the first photosynthetic life-forms that had evolved on Earth because oxygen is a dangerous waste for their metabolism. Photosynthesis harvests ample energy from sunlight instead of using chemical processes, which are less efficient than photosynthesis and rely on more limited resources.

It is a fascinating play enfolded once photosynthesis evolved. Initially, oxygen increased in the atmosphere. The oxygen build-up in the ocean was delayed. Oxygen concentration increased to about-modern levels only two billion years after oxygen appeared for the first time. Finally, a network of multiple geochemical feedback-loops relate biosphere, oceans, atmosphere and the lithosphere.


Finally, all oxygenated...

Finally, the photosynthesising algae and bacteria ruled the seas. Nearly 4 Billion years in its history, Earth switched into its present oxygenated stage. The play had been settled in favour for life as we know it. The Ediacaran [*] started 600 Million years ago; first complex animals and plants lived in a widely oxygenated ocean. To grow and store energy in their tissues, the plants tap into the ample energy that sunlight provides. Animals get sufficient oxygen supply to consume plant tissue vigorously. The continents were barren land, but that would change rapidly. A long-lasting phase of Earth history came to its end, oxygen and carbon-dioxide are taking over from sulphur, iron, hydrogen and methane.

Since the Ediacaran, the oxygen concentration in the atmosphere varied around present values. Feedback between geochemical cycles and the biosphere cause variations of the oxygen concentration, but keep its excursions limited. Up to recent times the same could be said for the carbon-dioxide concentrations; feedback between geochemical cycles and the biosphere kept excursions of carbon-dioxide concentration limited. Now humans have changed that balance and put on stage: anthropogenic global change. Human economic activity, burning fossil fuels to drive economy of billions of people, kick the feedbacks of carbon fluxes out of current balances. 
Ukko El’Hob

[*] from Wikipedia: “The Ediacaran Period (ca. 635-542 Mya) represents the time from the end of global Marinoan glaciation to the first appearance worldwide of somewhat complicated trace fossils (Treptichnus pedum). Although the Ediacaran Period does contain soft-bodied fossils, it is unusual in comparison to later periods because its beginning is not defined by a change in the fossil record. Rather, the beginning is defined at the base of a chemically distinctive carbonate layer that is referred to as a "cap carbonate", because it caps glacial deposits. This bed is characterized by an unusual depletion of 13C that indicates a sudden climatic change at the end of the Marinoan ice age.”

This text was inspired by the article “The rise of oxygen in Earth's early ocean and atmosphere” by Timothy W. Lyons, Christopher T. Reinhard and Noah J. Planavsky, which was published in February 2014 in Nature. Many insights are taken from “The global oxygen cycle “ by S.T. Petsch, which was published 2003 by Elsevier in volume 8 of in the “Treatise on Geochemistry” (Editor: William H. Schlesinger. Executive Editors: Heinrich D. Holland and Karl K. Turekian). Any inconsistency, error or slanted statement is responsibility of the author.

Thursday, 20 February 2014

Terraformer’s risk

Humans are engineers, even the artists. We humans engineer the surface of the globe; we change the Earth’s climate; and we drive other species into extinction. We do not do this on purpose. It is by-product of our sheer number and the way how we function as society. However, recently we got worried, at least a bit and some of us. We may got it wrong. Our way of living, producing or consuming does not look sustainable for long.

Some decades ago, scientist discovered that the atmosphere filtered less of the solar ultraviolet radiation. More of that damaging radiation reached the ground. Too much ultraviolet radiation is increasing the risk of skin cancers. The phenomenon of reduced filtering of ultraviolet radiation was called "ozone-hole". Ozone in the high atmosphere blocks ultraviolet solar radiation. However the ozone got broken up by substances that leaked from industrial production or industrial goods. The depletion of ozone happened mainly in polar regions at the end of the winter season. The culprit were chlorofluorocarbons (CFCs) and other compounds, such as carbon tetrachloride (CCl4) and carbon tetrafluoride (CF4) that were transported into the high atmosphere. Action was needed. A global agreement was found. The Montreal Protocol (1987) was negotiated to ban these ozone destructing substances. Nowadays the ozone hole is closing [*]. A global policy of regulating emissions was successful.

The same kind of policy also was successful on more regional scales. Regulated reduction of sulphur emissions reduced acid rain. Banning of certain pesticides saved birds from extinction. Thus a general experience formed. Regulations to reduce pollution at the sources showed to be a successful policy to improve living conditions. These regulations could be negotiated when they could be combined with a reasonably cheap technology. The intended shift of technology got economically feasible.

Image Credit:
Nowadays we face anthropogenic climate change, because of the massive carbon dioxide emissions from burning coal, gas and oil. In view of human experiences it seems obvious to apply the known mix of regulation and engineering to reduce anthropogenic climate change. Just as air pollution that was causing acid rains has been reduced by cleaner combustion processes; or such as ozone destructing chemical coolants have been replaced by other substances. The common approaches of these and other success-stories were to reduce threat to global or regional earth systems by withholding emission, replacing substances or limiting their use cases. Thus, the successful approach was a technological fix combined with a regulatory measure both targeting the “start of the pipe”. 

Unfortunately, targeting mitigation of anthropogenic climate change is more difficult. Applying a “start of the pipe” approach to climate change faces the issue that mankind should reduce inputs where its hurts, namely reducing much the amount of energy that is produced from burning fossil fuels. However, capping burning of fossil fuels would be disruptive for the economic structures or the consumption pattern of many developed and developing industrialised societies. Replacing fossil fuels with other energy sources seem to be difficult, for technical and economic reasons [1]; notwithstanding "unfavourable power-plays".  On the other hand, striving towards “global sustainability” through lesser use of energy would require drastically adjusting the current production and consumption patterns at a global scale. Achieving that seems to be beyond human political skills.

Facing that dilemma, affordable geoengineering looks tempting for some. Contrary to an approach of global sustainability through lesser use of energy, “geoengineering” deploys a “technology fix” to mitigate anthropogenic climate change. The fix aims to modify the earth’s climate system. The modification shall offset the stronger greenhouse effect that is caused by the  increased carbon dioxide concentration in the atmosphere.  Thus the question arises, whether  humans may endeavour to engineer the Earth to counter climate change hazards when they are facing the dilemma that they are not able "to reduce radically energy that is produced from burning fossil fuels"?
from [**]
Traditionally, modern humans are much inclined to look for technological fixes for problems, because well engineered technological methods have created their modern societies.
However the geoengineering technologies that counter climate change by other means than carbon capture at combustion are of a particular nature. They differ from the technological fixes that,  combined with negotiated regulatory actions previously have been applied to limit threats to regional and global systems. Most of the proposed geoengineering technologies target other parts of the climate system but the carbon-dioxide input into the atmosphere.
These technologies do not work at the “start of the pipe”. Instead they address either the "end of the pipe", such as re-forestation or ocean-fertilizing technologies or they tackle other parts of the climate system, such as reducing incoming solar radiation through particle injection into the higher atmosphere. Therefore, these geoengineering technologies differ qualitatively from the known success stories of human mitigation of anthropogenic environmental threats. Should these technologies be part of the toolbox to tackle anthropogenic climate change?  Should these technologies  be perceived referring to their qualitative difference?

“The acceptability of geoengineering will be determined as much by social, legal and political issues as by scientific and technical factors” [2], conclude Adam Corner and Nick Pidgeon (2010) when reviewing social and ethical implications of geoengineering the climate. In this context  of “acceptability” It is to debate that most geoengineering technologies are “end of the pipe technologies”, what involves an additional risk. 
from Space Daily [*]
A distinction is needed for technologies that do not tackle the initial cause of anthropogenic climate change, namely that the input of carbon-dioxide into earth systems is too high. This distinction is important because it labels the respective technology to exhibit an additional risk. The risk is not technical, but political or social. The risk is to related to public perception that uses the analogy with the proven framework of  “a technological fix combined with a regulatory measure”. However this framework got proven only in cases when the technological fix and the regulatory measure both targeted “the start of the pipe”. Only this framework provided so far an accepted public reference for successful mitigation policies to anthropogenic challenges of earth systems.

[*] /2012_Antarctic_Ozone_Hole_Second_Smallest_in_20_Years_999.html

[1]  It seems that carbon capture  at power plant would increase production cost  increase by 1.5-3.0 $c/kWh excluding cost of transportation and storage (Jeremy David and Howard Herzog, Massachusetts Institute of technology (MIT), Cambridge, MA USA, 6pp.

[2] Adam Corner and Nick Pidgeon 2010, Geoengineering the climate: The social and ethical implications, Environment Vol. 52.

Saturday, 14 December 2013

Humans are engineers, let’s terraform !

Credit: Hongkai Gao (via (i))
All humans are engineers, even the artists. Our close environment, the landscapes surrounding us are created by mankind. Intentional and unintentionally we do engineer the surface of the globe. We changed the surface, now we shift the climate. Threatened by climate change, shouldn't we endeavour to engineer the Earth to counter unintended climate change?  

If all nine billion people of the globe would live like European citizens – or people in North America, Australia, Japon… – that would blow up the globe. Up-scaling  advanced production and consumption patterns by a factor 20 is non-sustainable, and its down-scaling does not look feasible. Keeping current global imbalances of wealth and poverty does not seem fair. Striving towards “global sustainability” would require to adjust most of the the current production and consumption patterns. Without such adjustments, whatever these adjustments may be in detail, it seems unlikely to limit climate change to moderate scenarios of temperature increase and sea-level rise.

Evidently, human pressure on global systems is immense; unintentional terraforming is taken place going well beyond replacing pristine wilderness by rural landscapes. Humans change the state of the planet:

Dust Storm (Credit: Xuegang Mao (via
State of Planet Declaration: “Research demonstrates that the continued functioning of the Earth system as it has supported the welfare of human civilization in recent centuries is at risk. Without action, we could face threats to water, food, biodiversity and other critical supplies: these threats risk intensifying economic, ecological and social crises, creating the potential for a humanitarian emergency on a global scale.

In one human lifetime, an increasingly interconnected and interdependent economic, social, cultural and political systems have come to place. These systems put pressures on the environment that may cause fundamental changes in the Earth system and move us beyond safe natural boundaries. However the same interconnectedness provides the potential for solutions: new ideas can develop and propagate quickly, creating the momentum for the significant transformation required for a truly sustainable planet.

The defining challenge of the modern era is to safeguard Earth's natural processes to ensure the welfare of civilization while eradicating poverty, reducing conflict over resources, and supporting human and ecosystem health.

As consumption accelerates everywhere and world population rise, it is no longer sufficient to work towards a distant ideal of sustainable development. Global sustainability must become a foundation of society. It can and must be part of the bedrock of nation states and the fabric of societies.” [a]

Contrary to a negotiated approach towards global sustainability, “geoengineering” is understood to deploy a “technology fix” for the same purpose, namely to limit climate change, leaving current production and consumption patterns unchanged.

Four scenes on engineering

Jan Mayen island-  Credit: Sophie Tran (via
Imagine! Your are on an intercontinental flight. The flight is well packed. It is warm in the cabin, too warm, and not really comfortable. The crew announces that the cooling system should be re-engineered in-flight because it is insufficient for the high number of passengers on the flight. You learn that preparatory work will start soon, that the Oxford principles [b] have been respected and that so experiments would be undertaken soon. How would you respond?

Recall and imagine! Oil-based fossil-energy-age is halfway; the moment of peak oil is close. The planet is well packed with people. It is getting warmer. It is not comfortable. The chef-scientists of the G8 consider that geoengineering should fix that by providing additional cooling for the planet. You learn that preparatory work will start soon with some experiments. How would you respond?

SPICE -experiment (ii)
Recently the science magazine “Physics Today” [1] discussed why an experiment of the SPICE project “stratospheric particle injection for climate change” had been cancelled. The experiment foresaw to spray particle loaded water into the atmosphere 1000 meters above ground level [c]. The purpose of the experiment was to research how reflective particles in the atmosphere behave; one of the hypotheses to mitigate global warming. The experiment was designed to have no environmental impact. The experiment apparently was cancelled because proper governance of geoengineering experiments is lacking, including
addressing of patenting. Would you support that?

Recently the science journal “Nature” reported that injection of volcanic ash into the troposphere was planned to happen some days after publication of the article [2]. Ash-particles in the stratosphere modulate global temperature; for example, seasonal temperature dropped after massive volcanic eruptions, which injected ash into the stratosphere. Injection of 50 barrels of volcanic ash into the atmosphere at 3000 and 4000 meters altitude off the west coast of France should test an aircraft sensor for volcanic ash-hazards. It was planned to fly through “the largest artificial ash cloud ever made”. The experiment was not reported to have had an environmental impact. The experiment was not cancelled because governance of geoengineering experiments is lacking.... Would you support that?

Pieces of a puzzle

Considering the current state of moderating climate change, human capability to reduce its overall pressure on global systems seems to be limited, even if consumption of top-consumers is capped. On the contrary, human consumption of resources and pressure on global systems likely will increase as people of developing countries arise from poverty. Most people of the globe are living at relatively low levels of consumption. Their level of consumption will increase to get a fair share of the global resources; whatever fair may mean once someone does not live in poverty.

Their experiences made Humans much inclined to look for technological fixes for problems because that is what experiences taught. This approach, technological fixes had worked in the past and is something in which humans are good at. On the other side, the design and rolling-out of sustainable ways of economic and social functioning are a fringe activity in industrialised societies; they are getting their publicity, but little more. The German “Energiewende”, the attempt to replace in a decade-long process fossil-energy by renewable energies are mainly a technological project. However, what is wrong in focusing human efforts on methods in which mankind is strong?

Source - Environmental Protection Agency (iii) 
Well engineered technological methods have created our modern societies. These experiences are seen as a success at most places over the globe; whatever doubts emerged somewhere and sometime. Thus, it seems obvious to apply an engineering solution to climate change or global change issues too. In particular, as the identified, or the supposed, or the perceived threats to the environment of the past have been addressed successfully just in that manner. Air pollution causing acid rains has been reduced by cleaner combustion processes; ozone destructing chemical coolants have been replaced by other substances; genetically modified organisms got regulated by imposing restrictions on use; nanotechnology gets assessed for the limits of use-cases.

So far, a combination of public awareness and political concern, of technological fixes and negotiated regulatory actions has been applied to limit threats to regional and global systems, which were caused by pressure of human production and consumption patterns. So far, none of these methods, which were put in place, neither the technological fixes nor the regulations had to put into question the consumption pattern of the modern industrialised societies. Also so far, these methods were enough to reduce pressure on global or regional systems by reducing inputs without impacting on current production and consumption patterns. Common to these methods was to reduce inputs into global or regional systems by withholding emission, replacing substances or limiting use cases for certain substances. Thus, in these cases the selected approach was a technological fix or regulatory measure targeting the “start of the pipe”. Mature solutions to environmental threats replace “end of pipe” approaches with “start of the pipe” solutions; handling sewage water being the most pertinent historical example. What are situations in which “start of the pipe” are less appealing?

Applying a “start of the pipe” approach to climate change faces the issue that mankind should reduce inputs
were its hurts, namely reducing radically energy that is produced from burning fossil fuels. Capping burning of fossil fuels would be disruptive for the economic structures or the consumption pattern of the developed and developing industrialised societies. In addition, the disruptive change should take place in a manner that is coordinated at the scale of the globe. This seems a recipe for a “mission impossible”. The pace of negotiations on climate change matters clearly shows this. On the other hand, the consequences of a run-away climate change and the price of business as usual scenario looks forbiddingly high, as well in economic as in social costs that likely will be caused by climate change. Facing that dilemma affordable geoengineering looks tempting for some. Mankind could build on its strength, avoids disruption of the economic structures or the consumption pattern. The immediate downside of doing geoengineering is the feeling to get “in-flight re-engineered”; notwithstanding that geoengineering methods would have to be tested, evaluated, agreed and regulated before being deployed. By whom?

However geoengineering technologies, which counter climate change by other means than carbon capture at combustion, are of a different nature than the technological fixes and negotiated regulatory actions, which have been applied to limit threats to regional and global systems. Increasing the surface albedo to increase backscattering of sun-light, sheltering sun-light by aerosols or clouds in the higher atmosphere, capturing excess carbon by ocean fertilisation, afforestation etc.; all these technologies target other parts of the climate system but the carbon-dioxide input into the atmosphere. Therefore, many geoengineering technologies differ qualitatively because they do not tackle the initial cause, namely the carbon-dioxide inputs that are too high. Possibly, a technology that reduces inputs at the sources might gain more easily public support for its application. That may happen at least “in principle” and under the assumption that its cost is considered to be appropriate. Whatever appropriate may mean in a given situation, likely “appropriate” would mean that the cost would not be disruptive for the current economic structures or consumption patterns. Is that a pessimistic view?

In analogy to geoengineering; suppose that your ship has a leakage. Would you propose a lasting solution by installing stronger pumps and advocate heavier pumping? Such a proposal might be accepted in an emergency situation, and only if you propose a proven technique. Astonishingly, the Dutch do so for a substantial part of their country since centuries, and they plan to do so with rising sea level. But where else the Dutch people would like to be but in the Netherlands. Where else they could go? Thus, plan-fully the Dutch step up norms and constructions to face a sea-level rise of one meter in a century. They run their pumps to keep the water out “behind the dike” as they did it since centuries. In a more desperate situation people also would opt for "trial and error method" to confine a threat. This was done very much to confine the damaged nuclear reactors after the Chernobyl and Fukushima accidents. How massive these confinement activities may have been, they were deployed only on a very small scale compared to what geoengineering would involve.

So far for analogies; but what about developing and testing “technological fixes”, i.e. “stronger pumps”, as long as you have the opportunity to do so without being driven by an emergency situation? Would it be appropriate to develop in a regulated manner some affordable geoengineering technologies [3]?

Ukko El’Hob
Modified contribution to the blog of the International Association for the Promotion of Geoethics

[1] David Kramer, 2013 Geoengineering researchers ponder ethical and regulatory issues, Physics Today Vol. 66(11).

[2] Alexandra Witze 2013, Volcanic-ash sensor to take flight, Nature Vol. 502

[3] Adam Corner and Nick Pidgeon 2010, Geoengineering the climate: The social and ethical implications, Environment Vol. 52.

(i) This is a snapshot on the train from Lijiang to Kunming, Yunnan Provice in China. The terraced field is the creature of remaking nature, and the symbol of harmonous life style between human being and environment. No conquer, but live together.

(ii) Diagram of test. Click the image to view full size (53KB). Copyright Cambridge University Engineering Department.


[a], “State of the Planet Declaration" adopted by the conference “Planet under Pressure” 26th -29th March 2012 in London.

[b] In December 2009, the Oxford principles, initially drafted by scholars were endorsed by the to UK House of Commons Science and Technology Select Committee on “The Regulation of Geoengineering” making them a national-level policy statement on responsibly executed geoengineering research.

[c] The injection height of 1.000m, following habitual definition, would be much below the stratosphere habitually having a lower limit around 10.000m. However, “SPICE” is not a mis-name of the project. The cancelled experiment was part of a much bigger undertaking that apparently run also into difficulties because of a dispute about patent rights for geoengineering techniques (see: D. Cressy 2012, Geoengineering experiment cancelled amid patent row, NATURE, Vol.(485)