Sunday, 17 May 2015

Engineering the Anthropocene

We humans are an engineering species, pushing the frontier of what we know to engineer. Fully embedded in that aeon-old tradition and now facing anthropogenic change, engineering of earth-system dynamics is on our agenda. It will happen through greening of production systems and may happen through decoupling of production and ecosystems (ecomodernism) or modifying processes of the earth-systems (geoengineering). 

         Reservoir in the Italian Alps (Daniele Penna)
Modern people are re-engineering Earth, although involuntarily, by their number and consumption of renewable and non-renewable resources. We are "terraforming by number". 

Albeit standing in an aeon-old tradition, greening, ecomodernism or geo-engineering differs from habitual engineering endeavours of our species. Anthropogenic global change - e.g. climate change - prescribes global commons for all people, irrelevantly how these commons alter. The impact on all people loads this engineering endeavour, anthropogenic global change, with an unprecedented level of implicit value-issues.

Human Geosphere Intersections

Nowadays the humankind's impact on geosphere has reached a magnitude that it is proposed to re-name the present geological time as "Anthropocene" (Todd and Erlandson 2013). Scientists still debate the timing of the onset of the Anthropocene. Some fix it at 16th July 1945 the explosion of the first atomic bomb because that date could be a marker for the onset of "great acceleration" (Zalasiewicz et al. 2014).

Agrarian landscape of Marche region (Daniela Pennesi)
The notion Anthropocene convenes a double insight. First that development paths of the history of humankind and earth-systems intersect. Second that the sphere of our intra-species interactions between people (be it: technical, economic, social, cultural, artistic, public, collective or individual interactions) now are an intrinsic part of the earth-systems of the "Anthropocene" (Bergthaler Hannes et al. 2014).

Oil pump jack in Luling, Texas (Stephanie Zihms)
Societies abundantly apply geosciences. Most of the engineering works for transport systems, energy systems, dwellings, agriculture, waste treatment, etc. have the overarching function to dovetail economic activities with the geosphere. Craftsmen, technicians, architects and engineers apply geoscience insights when engineering environments or creating artefacts, e.g. extraction of minerals, the stability of foundations, or ventilation of buildings. Understanding the features of rock, soil, water and air is essential for the production of many goods. Also, maintaining living conditions and individual well-being is impossible without applying insights into the functioning of the intersections of human activities and the geosphere. These insights (Langmuir and Broecker 2012) may not be recognized as particular because they are part of the noosphere as experiences, common sense, general education or specific vocational training.

Many people living in Western cultures perceive the scenario of anthropogenic change as a threat to their lifestyle and well-being. Non-surprisingly, jointly with the perception of ‘being threatened' the classical response pattern of our species also emerged: "engineering of Human Geosphere Intersections" is proposed.

Rice field in the delta d'Ebre
(Claudia Grossi)
The first engineering option, ‘incremental greening of production systems' is about dovetailing anthropogenic and natural fluxes of matter to mitigate human impact on earth-systems. Today that engineering approach is already a confirmed feature of governmental steering of production systems; the public debate mainly is about the pace and degree of ‘greening'. The historical forerunner of that engineering option seem to be the energy-limited economies prior to the industrial revolution (Brown 2012, Fressoz 2012) that focussed on resource efficiency.

The second engineering option, “Ecomodernism” (Asafu-Adjaye et al. 2015) is the most recent branch of thought within the philosophical trail of "better engineering". Its protagonists advocate pushing urbanisation and non-fossil fuel power production to a level that matter is cycling predominately within the human economy. They argue that an economy of a stable human population of mainly urban lifestyle could decouple from the geosphere and biosphere to a fair degree. That engineering option seems to be the classical philosophical choice of Western, industrialised societies, namely to gain independence from nature.

 takes a sample with his grabber.
(MARUM, Germany)
The third engineering option, ‘geo-engineering’ is about how to adjust earth’s physical and bio-geological systems so that their modified functioning counters the impact of human economic activities on fluxes of matter and energy. That engineering option possibly seems to be the classical aeon-old cultural action of our species, namely to adjust the environment to our ways of being (Corner and Pidgeon 2010).

Each of these options exhibit the conventional human response pattern in face of problems, namely to tackle them through engineering the environment. Anyhow, irrespectively of the option taken all three options put the understanding of the intersection of human economic activity and geosphere forcefully into the centre of the lifestyle of all people.

Ethics at Human Geosphere Intersections

The intersection of people's activities and the geosphere is not a major storyline in European (Western) history. Nevertheless, history could be re-written for example as a story of engineering hydraulic works for irrigation systems, waterways, power-systems or sanitary systems (Pierre-Louis Viollet 2000) that were built to intersect human activity and geosphere.

In order to facilitate production and reproduction, engineering is the intended, value-driven change of environments. To that end, engineering includes building of infrastructures like shore defences, which purposefully and visible interact with the geosphere. Likewise engineering includes designing production systems, urban dwellings and consumption patterns, which firm but invisible couple with the geosphere through cycles of matter and energy. Last not least engineering is about how people govern the appropriation of living and non-living resources from the environment. Thus engineering is about value systems, cultural choices and lifestyles.

The processes and phenomena that describe the intersections of human economic activity and geosphere are omnipresent, although they may pass unnoticed by many. The life of people will alter when the intersections of the noosphere, biosphere and geosphere gets modified. People will judge the alternations on the basis of their values and insights into these intersections.

Stratospheric ozone depletion was the first global change process identified that got regulated including engineering choices (replacing coolants). As illustrated by the phenomenon of stratospheric ozone depletion, exact cause-effect relations are difficult to determine and regulate. The processes that govern the dynamics of the Human Geosphere Intersections are non-linear, networked and therefore dynamics are complex and difficult to forecast (Allenby and Sarewitz 2011). For any of the three engineering options to alter the Human Geosphere Intersections (‘greening'-, ‘ecomodernising'- or ‘geo-engineering') ethical dilemmas and non-intended effects are to be expected.

The ethical dilemmas will take the form of conflicting values and uneven distribution of risks, impacts, losses and benefits. The non-intended effects may range from compromising basic needs to challenging individual lifestyles. Consequently, ethics of risk-taking, managing uncertainties or exploring and revising options will be needed when altering Human Geosphere Intersections.


Erosion at work (Joern Behrens)
At the beach on the island of Juist (German Bight)
wind of approx. 5 Bft erodes sand quickly,
but the shells keep a number of small "hoodoos"...
Humans are an engineering species. That was a successful approach, so far, as the recent exponential growth of number of people showed. The engineering power of our species is now up to the point that people start to transform the geosphere, e.g. are starting the Anthropocene. So far, the transformation was non-intended, non-planned, not engineered. This phase of history comes to its end, now the intended transformation of Human Geosphere Intersections is scheduled: be it through 'greening', 'ecomodernism' or 'geoengineering'. What ever the particular choices will be, they will be value-loaded interventions into the intersections of humankind's activities and the geosphere. Therefore, geoethics of an engineering species for a mature Anthropocene are needed. 

Ukko Elhob
Credit for pictures: imaggeo &  Press des Ponts
Allenby, Branden R. and Daniel Sarewitz 2011, The techno-human condition, MIT Press, 222p.
Asafu-Adjaye, John et al. 2015, An Ecomodernist Manifesto, April 2015,
Bergthaler Hannes et al. 2014, Mapping Common Ground: Ecocriticism, Environmental History, and the Environmental Humanities, Environmental Humanities Vol. 5, pp. 261-276
Brown, Azby 2012, Just Enough: lessons in living green from traditional Japon, Tuttle Publishing, 231p.
Corner and Pidgeon 2010, Geoengineering the climate: The social and ethical implications, Environment 52(1), p.24-37
Fressoz, Jean-Baptiste 2012, L'Apocalypse joyeuse - Une histoire du risque technologique, Le Seuil 312p.,
Langmuir Charles H. and Wally Broecker 2012, How to build a habitable planet, Princeton University Press 718p.
Todd J. Baje and Jon M. Erlandson 2013, Looking forward, looking backward: Humans, anthropogenic change, and the Anthropocene, Anthropocene (4), p.116-121
Viollet, Pierre-Louis 2000, L'hydraulique dans les civilisations Anciennes, Presses Ponts et Chausssées, 374p.
Zalasiewicz et al. 2014, When did the Anthropocene begin? A mid-twentieth century boundary level is stratigraphically optimal, Quaternary International (Available online 12 January 2015 )

Friday, 8 May 2015

International Association for Promoting Geoethics (IAPG) - Official Blog: Geoethics as transdisciplinary meeting grounds...

...: Geoethics as transdisciplinary meeting grounds by Felix Riede Felix Riede (Head of the  Department School of Culture & Society, Aarhus University, Denmark; email: quoted:

 "..past human-environment relations and the impact of extreme environmental events – especially volcanic eruptions – on past communities. Attending the session on geoethics struck a deep cord with me. Several of the presented papers promoted a more explicit ethical engagement of geologists with society through the medium of geoheritage and geological practice. Martin Bohle in particular argued that narrative tools – stories – could be employed as powerful tools for generating interest in and engagement with issues such as environmental degradation, pollution, sustainability and risk. What I find interesting here is that this use of narrative as a way of bridging science, policy-making and public engagement is promoted in very similar terms by sociologists and scholars in what is called the Environmental Humanities. "

Saturday, 25 April 2015

Earth-centricity and Story-telling

This essay is discussing narratives as a means for people to associate themselves  with the intersection of people's activities with the geosphere.


As the anthropologists discovered, the human species is a storyteller by evolution. 

Nowadays, engineering and science are part of human story-telling, although their subjects seldom are treated as part of mainstream stories; with the exception of dramatic or outstanding events that reach the headlines. Still, the exception to the exception is the daily weather forecast, which is the geoscience narrative par excellence, possibly with a history reaching back deep into prehistoric times. 

Credits: imaggeo - Irene Marzolff "Dung Cakes"
Engineering and science shape the intersections of humans and their environments including intersections with the “geosphere”. Some of these intersections are more obvious, such as motorways, irrigation systems, hydro-power plants or shore defences. Others are less obvious, such as slope stabilisation, pumping of groundwater, sewage water treatment or beach nourishment. And further intersections, such as anthropogenic climate change, ocean acidification or habitat fragmentation, only are recognized through science-based insights into earth-systems.

Narratives, thus stories should be a means for citizens to exchange about their intersections with the “geosphere”.

Traditional and Modern Context of Story-telling

Credits: imaggeo Saskia Keestra "Irrigation canal"
Most traditional earth-centric narratives of rural communities of earlier times have been lost or got modified radically in the global industrialisation process. These stories encapsulated advice and justification for a behaviour that shall sustain stable intersections with the “geosphere”; mainly focussing on how to shape the use of natural resources such as plants, animals, soil, farm land, water or ecosystems such as forest. These stories were means to sustain the intersection of people’s activity and the geosphere. To stay effective these stories related to the “sacrum”, thus to matters that are explained with faith-based reasoning, upon values and beliefs referring to the supernatural, which generally are common and shared in the community. In Greek mythology, for example, gods and people were affected by observed geo-forces. 

When natural phenomena were not explicable with the use of available knowledge and technologies shared social constructions of believes prevailed. Many events, which today are understood as ordinary and understood by scientific approaches, in the past had been considered extraordinary and narrated as such. Faith and referring to the marvellous were used to explain phenomena, to rule the exploitation of limited and common resources, finally to preserve the ecosystem/environment in which the community was settled. Some traditional rural, alpine or other isolated cultures maintained these approaches into modern times. 

Credits: imaggeo Liping Pang  "Deer Park, 
Queenstown, New Zealand"
This kind of thinking, although it is based on faith and belief, is encoding accumulated experience. It had the function to coerce the believer into a behaviour that is favourable for sustained existence. To encode proven practices into rituals that are relating to the “sacrum” takes time and effort, as cognitive science of religion describes. When established the rituals are stable in a given environment in spite of being ‘costly’ to the people. However the rituals can be broken beyond repair if the faith-bases, value and beliefs are disrupted, for example by scientific explanation of phenomena. Thus traditional earth-centric behaviour erodes if its sacrum-based foundations are questioned. 

Science and technology, industrialisation and global urbanisation require a different kind of earth-centric story-telling as traditional earth-centric stories. Now, at the fringe of the Anthropocene, people can base their earth-centricity on substantial knowledge base, mature scientific insight combined with lessons inherited from the past. Likewise modern “earth-centricity” can be built, within a historical context and a robust ethic vision, on humanities and the insight in the decisions and choices of the past that led to the modern world and people's power to intersect with the “geosphere”

Credits: imaggeo Antonio Jordanm "Fieldtrip"
Thus, taking a comprehensive account of natural science and research, humanities and history, anthropology, philosophy and politics shall give the possibility to tell a story, first, of the unplanned making of the Anthropocene and, second, how to shape a mature Anthropocene . The richness of such a narrative allows to counter dooms-days scenarios, which finally would hamper action, and which therefore are deeply non-ethical.

Applying these insights regarding traditional and modern story-telling, narratives seems particular needed for urban people, thus for more than half of the global population. Urban people rarely can notice how the “geosphere” intersects with their daily dealings. The built-up urban environment hides phenomena - putting weather and disasters a bit aside - that inform how much the local “geosphere” had been engineered to make that environment matching people's needs and preferences.

Narratives are a form of communication, by that expertise in sciences and humanities can meet insights in practices and values of practitioners of common trades or laypersons. Art, history and quotidian environment provide many opportunities for earth-sciences story-telling; they range from geomorphology to art including reference to the ‘sacrum’ - short list of examples:
  • The obvious: The Colorado River is a story about people intersecting with the geosphere. It has cut the Grand Canyon (USA) but does not flow into the sea because its waters are withdrawn for irrigation.
    Credit: imaggeo Ioannis Daglis
    "Colorado Horseshoe Bend"
  • The ordinary: The motorway stretching east from Brussels cuts through a strip of heather-covered sandy hills. These aeolian depositions originated from dry-laying basin of the North Sea during ice-age.
  • The pleasant: The Lago Banyoles in Spain has no outlet and is fed by bottom-springs of slaty water. This geologically young lake may end as salt lake hosting flamingos feeding on brine shrimp.
  • On art: Nature and scenery are two subjects presented by artists since ancient times. Paintings capturing landscapes of past times narrate about transformations. Paintings or mosaics show the extent of natural events, like eruptions or floods, modified landscapes.
  • On history: Human activities has marked landscapes with mining-sites, irrigation channels, abandoned networks of local trains and names that narrates of the waters or settlements on sandy soils.
  • More on history: At the time of the eruption of the Vesuvius, artists painted in many of the richest patrician houses reproductions of the volcano before the tragic event. These paintings have been discovered by archaeologists during excavations, and they helped to reconstruct the shape of the volcano, the neighbouring landscape along the coast between Ercolano and Pompei, and the engineering works of the Romans such as aqueducts and roads.
  • On the 'sacrum'; Crater Lake is situated in a caldera in south-central Oregon. It has neither inflow nor outlet, and is known for water clarity and thus its deep blue colour (reflecting the sky and backscattering blue light from the water). The lake is deep, it was formed around 7.700 years ago by collapse of a volcano. To settle water balance of the lake evaporation is compensated by rain and snowfall, and thus the renewal of the lakes water-body is slow taking 250 years. It is a unique lake that previously was a sacred site for the native Klamath tribe. Their legends tell of battling gods, of sky and underworld. The volcano was destroyed in the battle, creating Crater Lake. Still nowadays, the Klamath people regard Crater Lake as a spiritual site.


Credit: imaggeo Ragnar Sigurdson
"Cooking Bread with Geothermal Heat"
People are engineers, even the artist; and engineers are artist. All people build and shape their environments to their taste and needs, applying their understanding of opportunities and constraints. In doing so, they intersect with the “geosphere” to a stronger or lesser degree, contentiously, consciously, naively or blindly. Perceptions, insights and values of people shape how they handle that intersection. Thus, implicitly a kind of geoethics is part of their culture.

Above this, people like stories. Media flood public with stories, bringing events and people into context, and make value-loaded judgements on behaviour of people and appreciation of events. Narratives – story-telling or narration as synonyms - acknowledge that people develop insights mainly by sharing stories. Communication leads people to shape their abstract mental concepts, to compare them with observations, to confront them with critical thoughts or creative ideas, to assess the cultural and social background, to make value statements and to express ethical views finally. Story-telling is a skilful human practice to describe perception of values in different contexts, to spread or to challenge their application. People are enforcing common views including values by sharing stories in their groups of peers.

Cedits: imaggeo Danielle Penna Alpin reservoirt
People's narratives about their intersections with the geosphere have evolved throughout history. Erstwhile widespread narratives about supernatural agents ruling this intersection, which were known many people, have been replaced by scientific descriptions, which are known by some people; and sharing of earth-centric narratives among people ceased. However, as illustrated by the examples presented above, many opportunities exist nowadays for narratives on intersections of people's activities and the geosphere. These narratives have a rich content with many features but science-elements only. Thus modern earth-centric narratives can be told about people and their intersections with the geosphere. These narratives can be positive in content, may overcome doomsday-cry, and do not need faith in the supernatural for being means to enforce constructive behaviour favourable for sustained existence.

Credit: imaggeo Geology for Global Development
"Guatemala City"
To get public awareness for narratives on intersections of people's activities and the geosphere, they have to be spun to reaches conversations of citizens, and therefore they have to be anchored in daily events. Thus, these narratives have to be both earth-centric and society-centric. Opportunities for society-earth-centric narratives are multiple, because earth-science know-how is relevant for both economy and value setting in contemporary societies. Earth-science know-how bears on both the production of goods, living conditions and individual well-being and on insights into the functioning of Earth's systems, the impact of humankind's activities on biogeochemical systems on Earth, and the evolution of live-bearing planets. When interwoven with arts, linguistic and cultural histories, this double bearing can offer a rich matrix for earth-society-centric narratives of people's intersections with the geosphere.


Credits: imaggeo Cyri Mayaud "Planina polje flooded"
Summarizing, why 'modern earth-science narratives are needed'? Namely, to influence practices on how people's activities intersect the “geosphere”. How to narrate? By weaving diverse concerns into common threads that draw on a wide range of perspectives: be it beauty or particularity of ordinary or special phenomena, evaluating hazards for or from mundane environments, or connecting the scholarly investigation with concerns of citizens at large. To increase general interest in earth-science narratives attention of various social groups have to be gained, which have access to a high density of information. To reach these groups, digestible rich messages are needed. Earth-science topics have to be woven into culturally rich narrations of multiple forms that offer a wide range of perspectives how people's activities intersect the “geosphere”, so that people can connect to them and thus associate themselves with geoethics, in the end.

Ukko El'Hob

Wednesday, 8 April 2015

What is Geoethics ?

The text below is derived from descriptions found at and;
written following a FB-debate around the "Wikipedia stumb" for Geoethics.

Geoethics consists of the research and reflection. Its subject are those values that guide appropriate behaviors and practices where human activities intersect the Geosphere. As such, Geoethics is an interdisciplinary field between Geosciences and Ethics. It involves Earth and Planetary Sciences including planetary geology and astrobiology, as well as applied ethics.

Geoethics deals with the way of human thinking and acting in relation to the significance of the Earth system and its modeling. As such Geoethics deals with the ethical, social and cultural implications of earth-science research and practice, providing a point of intersection of Geosciences, Sociology, and Philosophy.

Credits: Imaggeo - Daniele Penna [*]
Regarding the study of the abiotic world Geoethics covers the necessity to consider suitable protocols, scientific integrity and a code of good practice. To that end, Geoethics includes geo-educational, scientific, technological, methodological and social-cultural aspects. Geoethics refers to such subjects as sustainability, development, geo-diversity and geo-heritage, frugal consumption of resources, appropriate handling predictability, risks and mitigation of natural hazards, geoscience communication, and museology

Geoethics represents an opportunity for Geoscientists to become more conscious of their social role and responsibilities in conducting their activities and to influence the awareness of society regarding problems related to geo-resources and geo-environment.

Reservoir in the Italian Alps; by Daniele Penna, Free University of Bozen-Bolzano, Italy,, Italy; Taken on 17 August 2009Submitted on 02 March 2015

Mountain natural streams and reservoirs have a relevant hydrological and ecological importance since they represent reliable sources of freshwater supply to lowland regions and high-quality habitats for fish and cold-water communities. Moreover, streams in mountain environments are of significant importance for users in several socio-economic sectors, such as agriculture, tourism and hydropower. Given the vulnerability of mountain streams and catchments to the impact of climate changes and the increasing concern about water supply in mountain regions, there is the urgent need for scientists to face integrated, multidisciplinary catchment-scale studies addressing implications of climate change on water resources management and flow regimes.

Sunday, 28 December 2014

Lesson, insight, and afterthought.

One Ocean, One Index – a 'Composite Essay' on Opportunities and Limits.

The ocean-health index is a challenging attempt, namely to describe a set of assets through a single index. Setting up the index and reviewing it teaches lessons on the human-ecological intersections of the human-ocean system, including the issue of appropriate mathematical methods "how to calculate its scores".

My first insight:

Setting up an ocean-health index [1] was an a lasting contribution to the management of the human-ocean system. An ocean-health index can be a tool for comparison of national and regional policies, benchmarking, and qualification of development options. That is much needed to manage global commons like the ocean.
Implications of the (simple) mathematics to calculate the score of ocean-health index have been analysed [2] and suggests that the mathematical method chosen for calculating the score is causing bias of the index. The method, “weighted arithmetic average”, makes the score insensitive to less appropriate balances between low-performance assets and better-performing assets. The feature “unconstrained mutual substitution between assets” that is implicit to the averaging method to obtain the score of the index limits its usefulness [2]: "policy assessment and advice based on an index with unconstrained 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 not the case."

My second insight:

Constrained mutual substitution of assets should improve the assessment of the various oceanic features that are relevant for societal wealth and human development. 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.
Substitution possibilities should be constrained by the boundaries to the elasticity of the ocean system. If we do not know this ‘elasticity’ then “strong sustainability concept” or even the “precautionary principle” should be applied. Substitution possibilities should provide for a margin for management decisions - not everything goes, not all is forbidden – to render the ocean-health index a practical tool with operational value.

My third insight:

For better or for worse, a common and robust ocean-health index is a welcomed management tool, and should be part of any mature ‘blue economy strategy’. Thus, it is important to strengthen the index in a manner that enables its sound use in practice. Thus, furthering the analysis is needed, be it of suitable asset substitution or how to describe the substitution process in mathematical terms, to properly evaluate benefits, risks and development options of the ocean-human system.
In the absence of such an index, the alternative would be to manage all assets one-by-one using the "strong sustainability concept" or even the "precautionary principle". Such a choice has the intrinsic risk of a political process to retain only those assets that the strongest lobby considers to be most relevant. Such a situation certainly will be detrimental for the overall balance among assets, to the comparison of national and regional policies, benchmarking, and qualification of development options.
Thus, one composite index has a strong appeal. However, attention should be given to the averaging procedure, which, if too complex or perceived as too complex, would hamper application. To recall, the attractiveness of estimating the ocean-health index by a weighted arithmetic average is the simplicity of the mathematical procedure.

An afterthought: 

Possibly a two tiers approach may provide a useful compromise for now. Tentatively, such a compromise could be: (i) apply the "strong sustainability concept" to divide the entire set of assets in two sub-sets; one sub-set for the assets that match the respective threshold and the other sub-set for the assets that fail the respective threshold. (ii) calculate the score of the ocean-health index for both sub-sets and the entire set, and (iii) present the score for the full set with the scores for the sub-indexes as lower and upper bounds.

[1], [2] for references see "One Ocean, One Index – a 'Composite Essay' on Opportunities and Limits" 

Excursions - one, two, three.

The ocean-health index is calculated as a “weighted arithmetic average”. That “weighting” does not look too much as problem. It makes the averaging a bit more complex as taking a simple “arithmetic average”. The “weighting” allows to account for some features that are a bit more important as other. The more important assets get “a bit more” weight and thus they determine the average a bit more as the less important assets. Setting the weights may give some room for tweaking the average, but can be understood easily and therefore “tweaking or cheating” can be made evident.
The mathematics of an "arithmetic average" look even more innocent and non-problematic; likely it is the most frequently used methods to calculate averages. An "arithmetic average" makes good sense, if the same feature is measured several times, and each measurement has a small random error. An "arithmetic average" also makes a good sense if no preferences shall be made among measurements. If preferences shall be made then weighting measurements is a transparent approach to set these preferences. Pushing these considerations further: facing the intrinsic complexity to balance different assets using the arithmetic average is like taking the approach "one asset one vote". And, on the other hand, attributing different weights to different assets can help to reflect social or political choices without excluding a "minority asset"; thus it is like an "affirmative action". Thus, considering the averaging method from a political angle the "weighted arithmetic average" looks much like as "applying first principles".
Nevertheless, these apparently simple averaging is not an innocent choice. It applies a specific “normative frame[s]” [2] embedded into the index and thus applied to the management of the assets. In a nutshell: The difficulty with arithmetic averaging is just that no preference is made. This “normative frame”, the implicit assumption behind arithmetic averaging, may effect the usefulness of the index as a management tool.
Using an “arithmetical average” to score a set of assets implies the assumption: assets can replace each other and the same score is calculated. Thus, “unconstrained substitution possibilities” exist among assets to obtain the same average score. In the term “unconstrained substitution possibilities” the notion “substitution” means that under-performance for one asset can be balanced by better-performance for another asset; “unconstrained” 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, and offer a wide range of management choices.
Using a “weighted arithmetic average” does not alter qualitatively the assumption of “unconstrained substitution possibilities”. Using a “weighted arithmetic average” modifies the “cost” of the substitution: 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.

Excursion Two: A radical 'normative frame'?
Let's illustrate - by an example - “unconstrained substitution possibilities among various assets”: Assume first a shopping list of ten items for a tasty dinner; assume further getting these items in different quality and quantity, but so that, and this is the third assumption, the average “palatableness” of the dinner is the same. Evidently, a good starter may make good for an mediocre desert, or a good wine (or beer) compensates for…; but unconstrained substitution possibilities among the various parts of the dinner and same 'palatableness'? Common sense suggests that this may not work. However, consider a hypothetical "palatableness index" that is defined as the weighted arithmetic average of the quality and quantity of the items purchased for the dinner". In terms of that index, a dinner should have the same "average tastiness" as long as the score of the "palatableness index" is the same.
Evidently, “unconstrained substitution possibilities among various assets”, if it works, would be a framework for “a manager’s dream”. Such a framework would maximise the number of operational alternatives to amalgamate assets. In reality, "unconstrained substitution possibilities among various assets" is an exceptional case. It is rather "the real-world's manager's headache" that amalgamating assets is limited by their mutual substitution potential. The substitution potential may be limited for ecological, technical reasons or social preferences or economic viability to name but the most obvious. It is implicit for the application of ocean-health index to managerial or political choices that different assets can substitute each other, at least to some degree. It is implicit also, that assuming the full substitution of assets is problematic. Thus, how to describe these limitations by an appropriate mathematical method.

Excursion three: Mathematics for strong, weak or intermediate sustainability ?
The concepts of "strong sustainability" and "weak sustainability" can be used to compare different options to substitute assets. The "strong sustainability" concept constraints substitution options; all assets shall be kept above an asset-specific critical level. Under the "weak sustainability" concept, the substitution between assets is unconstrained.
In mathematical terms, the concept of “unconstrained substitution” is implicit to the ocean-health index calculated by a [weighted] arithmetic mean. Experienced managers of marine resources will be aware of limitations to substitution of assets, and thus will not accept any 'blind' averaging. However implementing that awareness in a competitive environment is fraught with difficulties, and therefore mathematical methods to describe “intermediate levels of substitution” may be appreciated as management tool.
The mathematical methods to describe "intermediate levels of substitution" are available [d]. Aggregation of scores for individual assets into a composite score under conditions of constraint or limited substitution can be described using ‘generalized averages' [e]. Arithmetic, geometric or harmonic averages are as special cases of the ‘generalized average'.

Obviously, intermediate levels of substitution of assets may be achieved for many real-world situations. Evidently, for many real-world situations it will be difficult to determine "what are boundaries to substitution?" Manifestly, any intermediate level of substitution of assets will depend on the specific ecological-human intersections of the respective human-ocean system. Nevertheless, whatever appears “obvious”, “evident” or “manifest”, it will be hard and tedious work to narrow the range of substitution possibilities. Therefore one may argue that "strong sustainability" should be applied across the board to guide management choices, and be it only for the sake of simplicity.

[2], [d], [e],  for references see "One Ocean, One Index – a 'Composite Essay' on Opportunities and Limits" 

The Ocean Health Index - mathematics visited.

One Ocean, One Index – a 'Composite Essay' on Opportunities and Limits.

The scrutiny: Composite averaging and intermediate level of substitution
Rickles and co-workers [2] illustrate how limited substitution possibilities can be implemented for the ocean-health index using appropriate mathematics, i.e. specific functional forms ("functions of functions") [f]. The mathematical methods for calculating the index can get increasingly composite. They may combine nested approaches, generalized means, variable setting of substitution, constraints on the overall score for the less-performing assets, "hard" lower boundaries, etc.
Evidently, such kind of "composite averaging procedure" lacks the simplicity of the arithmetic average. The "composite averaging procedure" is an elaborate model of the substitution possibilities, which has to be analysed with care; not only for its non-linear behaviour. Notwithstanding its complexity, such a model could capture our best understanding of the functioning of the ocean-human intersections through appropriate mathematics. As such it may be a useful research tool.

However, for any index to be a useful management tool (e.g. how to value different resources or options) the method how the score of the index is calculated needs to be understandable. Therefore, the mathematical complexity of the composite model may be too high, and many users may prefer the method "weighted arithmetic average". Rickles and co-workers [2] show how the score of the index depends on the mathematical method.

[2], [f]: for references see "One Ocean, One Index – a 'Composite Essay' on Opportunities and Limits"