Positive Feedback Loops to Propel the Sustainability Transition

David P. Turner / March 8, 2024

In the jargon of systems theory, a positive feedback means that a change in a system initiates other changes within the system that amplify the original change.

A clear example in the Earth system is the water vapor feedback:  as the atmosphere warms (e.g. from increasing CO2) it can hold more water vapor (mostly evaporated from the ocean), and since water vapor itself is a greenhouse gas, the atmosphere warms further (Figure 1).

A box and arrow diagram shows the steps in the water vapor and snow/ice albedo feedbacks to climate warming.

Figure 1. The water vapor (blue loop) and snow/ice albedo (red loop) feedbacks. Climate warming induced by anthropogenic CO2 emissions drives changes in the hydrosphere and cryosphere that amplify the warming. A plus sign means causes to increase and a minus sign mean causes to decrease. Image Credit: David Turner and Monica Whipple.  Figure appeared originally in the Technosphere Respiration Feedback blog post.

Positive feedbacks are generally considered destabilizing to a system, potentially pushing it into a new state.  Negative feedbacks aremore familiar, e.g. the furnace/thermostat cycle in home heating; they tend to stabilize a system.

The Earth system has significant negative feedbacks that have helped keep global mean temperature in a habitable range over its 4-billion-year existence.  However, these feedbacks (e.g. the rock weathering thermostat) operate at a geologic time scale, and are thus not going to save humanity from the vast geophysical experiment that we began by burning fossil fuels and boosting atmospheric concentrations of greenhouse gases.

We need something faster.  Hence, it is worth identifying and perhaps cultivating various positive feedback mechanisms that could support global sustainability.  Here, I’ll consider three varieties of positive feedback loops that might help us.

Type 1.  Psycho-social Positive Feedback Loops.

Humans have various cognitive biases, meaning our decisions are sometimes subject to unconscious tweaking.  These tweaking tendencies have genetic as well as experiential origins, and may or may not be helpful in any given decision.  Prestige bias, under which we are drawn to believe and emulate individuals who have achieved high status in our society, is an example. 

A cognitive bias that might help the spread of sustainability principles and practices is the conformity bias.  As the name suggests, we tend to adopt ideas and practices that are already embraced by a significant proportion, or the majority, of our society.  The positive feedback comes in because converts increase the proportion of the society that are believers, which strengthens the pressure on nonbelievers to conform.

Figure 2.  Conformity Bias Positive Feedback Loop.  Image Credit: David Turner and Monica Whipple.

The history of social norms and behaviors related to littering and paper recycling show evidence of conformity bias kicking in at some point.

Now that greater than 50% of Americans believe that climate change is for real, conformity bias may help enlarge the pool of believers, and hence the support for relevant policy changes. 

Type 2.  Technical-economic Positive Feedback Loops.

As new technologies become more widely adopted, the associated manufacturers begin to benefit from economies of scale, i.e. the marginal cost of production comes down as usage increases because larger production facilities are typically more efficient than smaller ones.  More efficient production means that the product can be offered at a lower price, and hence demand will likely increase.  This positive feedback loop can lead to rapid growth in product use.

An essential requirement for mitigating climate change will be conversion of the power sector from fossil fuel to renewable sources of energy.  This conversion is ongoing and is benefitting from economies of scale.  Installation of solar and wind power generators is expanding rapidly, in part because the economics are beginning to favor these sources over coal-fired plants.  The cost of installed solar panels and wind turbines has decreased over time because of economies of scale and rapid technical advances.  Hence, a virtuous cycle of more installations favors more decisions to go with renewables.

A second powerful technology-oriented positive feedback involves “network effects”.  Here, as a new technology becomes more widely utilized, its value to the user increases, and more users are recruited.  The spread of the telephone is the classic example. 

Figure 3.  Example of a Network Effect Positive Feedback Loop.  Image Credit: David Turner and Monica Whipple.

The network effect is readily applicable to the proliferation of electric vehicles (EVs).  The replacement of internal combustion engine powered vehicles with EVs is widely advocated to mitigate climate change.  This transition has started, and is fortunately accelerating because of positive feedbacks.  One feedback loop is that as more EVs enter the market, the economic incentives to build more charging stations has increased.  More charging stations makes it easier to take long trips, which reduces range anxiety and incentivizes drivers to purchase EVs rather that gas powered vehicles.

Type 3.  Socio-cultural Niche Construction Loops

Cultural evolution is the process by which the beliefs and practices of individuals and groups of various sizes change over time.  At the level of group selection, particular ideas and group practices may strengthen the group when faced with intergroup competition (e.g. intertribal warfare).

There are many group traits that are shaped by cultural group selection; for analytical purposes we can divide them into three types: sociological, technical, and ecological (Table 1, also below).  It is the constellation of these traits, including how they influence each other, that determines the success of a group.

Socio-cultural niche construction refers to the idea that human societies alter their physical environment (e.g. the vegetation, the energy infrastructure) in ways that reciprocally influence how the society is structured and functions.  Positive feedback loops among two or more of the group traits in Table 1 can result in rapid societal change.

If a group (e.g. a nation) invests (a sociological trait) in research and implementation of renewable energy technologies, the outcome may be a change in the mix of societal energy sources (a technical trait), which could result in cheaper and more reliable energy delivery to the society, which strengthens the society and encourages further investment in renewable energy sources.  The societal choice of energy source also influences the ecological trait of local air quality.  Improvement there would further strengthen the society and enhance group strength.

Figure 4.  Example of a Socio-cultural Niche Construction Positive Feedback Loop.  Image Credit: David Turner and Monica Whipple.

Conclusion

The various feedback loops reviewed here suggest that societal principles and policies are not simply top-down impositions on citizens.  Rather, they can be significantly strengthened or weakened by reciprocal interactions with features of the social, technological, and ecological environment.  To propel conformity bias regarding a particular value or technology, leaders and media can package it as a new social norm.  To propel sustainable technologies that benefit from economies of scale and network effects, societies can subsidize early stages of their development.  To foster revolutionary changes in technology (e.g. a renewable energy revolution), leaders must advocate for them based on the full range of their benefits to society.

These psychological and sociological considerations make the transdisciplinary aspects of Earth System Science ever more apparent.

Table 1. Examples of group traits that may interact to influence group selection.


Sociological Traits

Laws
Customs
Policies
Belief system (e.g. religion)
Type of political organization (e.g. tribe vs. nation state)
Type of military organization
Civic institutions

Technological Traits

Type of fuel for energy production
Form of transportation
Form of electronic communication

Ecological Traits

Local species composition
Local net primary production
Local air quality


Technosphere Energy Flow:  Time for a Course Correction

David P. Turner / February 5, 2024

Figure 1. The Earth at night gives an indication of technosphere energy flow. Image Credit.

The combustion of fossil fuels has powered the rise of humans from hunter/gatherers to planet-orbiting astronauts.  Currently, the energy production capacity of Earth’s technosphere (Figure 1) is on the order of 16 TW (see Box 1 or below for background on units).  Like Earth’s biosphere (the sum of all living organisms), the technosphere is a dissipative structure and requires energy to maintain itself and grow.

Two big problems with current technosphere energy flow are: 1) most of the energy is generated by combustion of fossil fuels, which release greenhouse gases that are rapidly altering global climate; and 2) the per capita distribution of global energy is highly uneven, with billions of people at the low end of the distribution receiving little to nothing.

The magnitude of technosphere energy flow is not really an issue.  Sixteen TW is small compared to the flow of energy associated with biosphere net primary production (on land and in the ocean).  The global NPP of around 100 PgC yr-1 is equivalent to about 63 TW of production capacity.  Note that the technosphere appropriates close to 25% of global NPP for food and biomass energy.  The technosphere and biosphere energy flows are both much smaller than the rate of solar energy reaching the Earth, which is about 1700 TW.

Transitioning away from combustion of fossil fuel to more environmentally benign forms of energy production is feasible, but will be extremely challenging and will take decades.  To do so, all sectors of the global economy – notably the transportation sector – must be designed to run on electricity.

A significant constraint to the transformation of the power sector is the slow turnover rate of the fossil fuel infrastructure (e.g. a coal fired power plant will typically last 50 years), which raises the issue of stranded assets if they are retired early.  Large reserves of fossil fuels will likely have to be abandoned, unless carbon capture and storage can be economically implemented (so far, a doubtful proposition).  Transitioning away from fossil fuels also means cessation of investment in the infrastructure supporting fossil fuel consumption, notably oil and gas pipelines, liquid natural gas (LNG) terminals (for liquification and regasification), and LNG shipping vessels.  The neoliberal doctrine about leaving investment decisions to the marketplace does not apply to the renewable energy revolution because fossil fuel users are still externalizing the costs of fossil fuel combustion (i.e. not paying for the impacts of associated climate change).  Hence, various subsidies, taxes, and regulations are necessary.

Despite the challenges, the global renewable energy revolution is underway, with rapid deployment of energy technologies such as solar, wind, and geothermal.  Nuclear energy is not strictly renewable but can contribute to minimizing carbon emissions.  The International Energy Association (IEA) suggests that 2023 was a turning point regarding the magnitude of global investment in renewable energy (spurred on by the Inflation Reduction Act in the U.S.).  Employment of technologies such as hydrogen fuel cells, grid scale rechargeable batteries, smart grids, and supersized wind turbines will speed up the transition process.  Decentralized energy production (e.g. household solar panels and small power plants) offers many benefits to both developing and developed countries.

With respect to the per capita energy use distribution problem, total energy consumption could stay the same while per capita energy use evened out to a level approximating that in Europe today.  However, consumers at the high end of the distribution are resisting reduction in their energy use (such as less air travel).  The more likely path to raising consumption at the low end of the distribution will be to increase total energy production.  The IEA projects global energy use will increase by 33 to 75 per cent by 2050 (to about 25 TW). 

The new energy demand will arise from increased per capita consumption along with an increased  global population (topping out at 9-10 billion this century).  More energy will be needed to substitute for various ecosystem services that are degraded or broken, e.g. energy to power water desalinization plants.  New energy intensive applications like AI are also emerging.

As developing countries build out their local manifestations of the technosphere, it is crucial that the more developed world helps them leapfrog reliance on fossil fuels and go directly to renewable energy sources.  In support of that trend, China has announced it will stop funding construction of coal-fired power plants in developing countries (albeit that it continues to build such facilities domestically).  The World Bank and IMF have introduced similar policies.  Critical political decisions about increased reliance on natural gas in particular are being made now (e.g. in Mexico) and should be strongly informed by the climate change issue.

Getting technosphere energy flow right will require continued technological and political innovation.  Success in this communal project will help actualize humanity’s long-term goal to build a sustainable planetary civilization.

Box 1.  Background on energy units

________________________________________________________________________

A watt is a unit of energy flow at the rate of 1 joule per second.

One joule is the amount of work done when a force of one newton displaces a mass through a distance of one meter in the direction of that force.

TW = Terra Watt = 1012 Watts = 1,000,000,000,000 Watts.

GigaWatt = 109 Watts = approximate capacity of 1 large coal-fired power plant.

PgC yr-1 = Peta grams of carbon per year = 1015 gC yr-1 = global net primary production in terms of carbon.

The energy equivalence of 1 gC (2 g organic matter) = 36 * 103 J

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Forms of Agency in the Earth System

David P. Turner / Januanry 5, 2024

When psychologists refer to individuals as having agency, they mean having the potential to control their own thoughts and behavior, as well as shape their environment.  As humans mature, they gain independence and agency.

The term is also used by sociologists in reference to collectives of humans who are organized to fulfill a specific purpose, e.g. a nongovernmental organization such as the Nature Conservancy that aims to conserve biodiversity.

As summed effects of the human enterprise on Earth begins to significantly impact the global biogeochemical cycles, one could say that humanity as a whole is beginning to acquire agency with respect to the Earth system.  We inadvertently pushed up the atmospheric concentration of CFCs to a level that significantly depleted stratospheric ozone, and we are now reducing global CFC emissions to restore stratospheric ozone.  Thus far, this new form of collective agency is better able to instigate global scale environmental changes than to mitigate or reverse them in the interest of self-preservation. 

Of course, human animals alone are ineffectual relative to the Earth system; it is really humans in combination with their physical machines, structures, and support infrastructure that have agency and are impacting the global environment.  Earth system scientists have proposed the term technosphere   for the amalgamation of humans and their manufactured artifacts.  Efforts are ongoing to estimate the mass and flows of energy and materials of the technosphere, and the principles by which it operates.

The technosphere was constructed over time to support human welfare, but in some views it has taken on a life of its own, e.g. witness our great difficulty in reducing fossil fuel emissions to mitigate climate change.  The rapid infusion of Artificial Intelligence into the technosphere will likely strengthen its autonomous tendency. 

The view of the technosphere as autonomous, as having more agency than the humans who are part of it, has generated considerable pushback from social scientists.  Firstly, it allows humans to abdicate their responsibility for technosphere impacts on the global environment, i.e. if technosphere dynamics favor ever increasing combustion of fossil fuel, what chance is there for mere humans to reverse that trend?  In contrast, a social scientist might argue that we must do the work of building institutions for global environmental governance and economic governance.

A second social sciences objection to assigning the technosphere too much agency is that it is not a homogeneous entity; there is not a species-wide “we” with its associated technosphere when discussing human agency at the global scale.  A relatively small proportion of humanity accounts for a large proportion of fossil fuels burned to date.  Since responsibility for fossil fuel impacts resides primarily with this proportion of humanity, support is building for differentiated responsibility with respect to mitigating and adapting to anthropogenic global environmental change.

Besides the technosphere, one other form of agency in the Earth system worth contemplating is the planet itself.  Geoscientist James Lovelock and biologist Lynn Margulis developed a conceptualization of planet Earth as a quasi-homeostatic system.  They named it Gaia – not to imply teleology, but to suggest its active, generative nature.  Despite a gradually strengthening sun and recurrent collisions with asteroids, Gaia has managed over billions of years to maintain an environment suitable for life.  Gaia operates by way of interactions among geophysical and biophysical processes, including mechanisms such as the rock weathering thermostat

At times, Lovelock was rather strident about evoking Gaia’s agency; he referred to the “Revenge of Gaia” in one of his book titles, alluding to the way Earth will react to anthropogenic changes.  Philosopher Isabelle Stengers likewise elevates the agency of Gaia to the level of “intruder” on our human-centric narrative about conquering nature.  These perspectives are perhaps overly anthropomorphic, but they succeed in evoking a sense of Gaia’s power.

An emerging synthesis of the ambiguities in applying the agency concept to the contemporary Earth system is the concept of Earth as Gaia 2.0.  Here, the technosphere is included along with the geosphere, atmosphere, hydrosphere, and biosphere in a new formulation of the Earth system.  Gaia 2.0 is meant to suggest that a network of feedback loops, including the technosphere, will be built so that a new form of global regulation involving both conscious acts (like a renewable energy revolution) and Gaian dynamics (like increasing sequestration of CO2 in the biosphere) is achieved.

The discourse on agency in the Earth system is rather abstract, and one might ask what work is really done by elaborating the agency concept in the context of the Earth system?  How does it help humanity deal with the multiple challenges posed by anthropogenic global environmental change?

Humanities scholar Bruno Latour argues that a conceptual benefit of thinking in terms of agents lies in creating a new arena of politics  ̶  the politics of life agents.  This new forum is where our attempts to alter the current dangerous trajectory of the Earth system (e.g. from an icehouse state to a hothouse state) will be negotiated.  Besides the technosphere, the participants in this new arena include Gaia – and all the biophysical forms (e.g. the Amazon rain forest) and geophysical forms (e.g. the Southern Ocean) within it.  These nonhuman forms are agents in the Earth system, though they cannot represent themselves directly; they must be represented by individual humans, civil society, and governmental institutions. 

Designating Gaian agents as participants in Earth system politics reminds us of our responsibility to represent them.  In my home river basin (the Willamette River, Oregon, USA), a nongovernmental organization (Willamette Riverkeepers) is currently in conflict with the federal Bureau of Land Management because BLM is not considering effects of proposed logging on fish and wildlife species, water quality, and carbon sequestration.  The Riverkeepers advocate for inclusion of all the river basin components  ̶  humans as well as nonhumans  ̶  as co-participants in an integrated process of river basin management. 

The interactions of humans, technology, and Gaia can be organized in the form of socio-ecological systems (SES) at various scales.  Levels of SES organization include watersheds, bioregions, and the planet as a whole.  In an SES, all the actors having agency regarding a particular resource are assembled to negotiate co-existence – again, evoking a political arena.  Feedback loops within an SES that involve humans, technology, and biophysical processes must be designed to maintain economic, social, and ecological well-being across the full array of SES constituents.  Building the relevant SES institutions remains a major challenge to natural resource managers.

Carbon Cycle Consequences of Vegetation/Climate Mismatch

David P. Turner / September 15, 2023

Planting a tree should include a species selection process that factors in projected climate change over the lifetime of the tree.  Image Credit.

Equilibrium between vegetation and climate refers to the state in which the species and ecosystem type best adapted to a particular area actually occupy that area.

At a geologic time scale, Earth’s climate is always changing and as climate changes, the best adapted species for a given geographical area likewise changes.  However, for a variety of reasons, the arrival and establishment of the best adapted vegetation may lag behind the climate change.  Biogeographers refer to vegetation/climate disequilibrium in this case.

Note that achieving vegetation/climate equilibrium may take hundreds to thousands of years, so the faster climate is changing, the less likely it is that the vegetation will remain in equilibrium with it.

The Holocene Epoch (from about 11,000 B.P. to present) was characterized by a relatively stable climate, and global vegetation has mostly equilibrated with the climate.  But now we have entered the Anthropocene epoch in which anthropogenic greenhouse gas emissions are driving a high rate of climate warming.  Consequently, long-lived vegetation is beginning to fall out of equilibrium with the climate over wide swaths of the terrestrial surface (albeit that humans have already massively altered global vegetation).

As the disequilibrium gets greater, forests in particular become more stressed and vulnerable to disturbances such as insect outbreaks and fire.

The incidence of fire is already increasing around the world because of climate change and we can expect that trend to continue.  For example, my simulations of vegetation change in the Willamette Basin (Western USA) project a several fold increase in the incidence of forest fire in coming decades as the climate changes.

The carbon cycle consequences of a growing vegetation/climate disequilibrium are significant.

1.  More fires mean more direct emissions of CO2 and more woody residues (dead trees), which will eventually decompose and emit CO2.  Local photosynthesis (CO2 uptake) is reduced in recently burned areas until the vegetation leaf area recovers.

2.  Forests stressed by climate change are increasingly vulnerable to pests and pathogens.  As with fire, associated damage to trees reduces growth and may cause mortality, and the residual dead trees gradually decompose and return CO2 to the atmosphere.

3.  Climate change is increasing Vapor Pressure Deficits (the drying power of the atmosphere), which tends to reduce stomatal opening and hence reduce photosynthesis and uptake of CO2.  Plant species are adapted to a specific range of VPD and can die when VPDs exceed their tolerance.  Interestingly, the increasing concentration of CO2 from fossil fuel emissions compensates to some degree for VPD-induced stomatal closure because CO2 diffusion into the stomata increases as the concentration gradient between leaf exterior and interior rises.  The net effect of these opposing factors varies geographically depending on many variables.

The global impact of increasing disequilibrium between vegetation and climate on the carbon cycle is concerning because it will likely reduce the current terrestrial carbon “sink”.  At the global scale, the net effect of biological carbon sources and sinks on land is a carbon uptake equivalent to about 29% of fossil fuel emissions.  Much of that carbon accumulation is in wood and soil.  The effects of vegetation/climate disequilibrium may reduce the current rate of land-based sequestration, which would leave more fossil fuel-based CO2 emissions in the atmosphere.  The annual increase in atmospheric CO2 concentration has increased in recent decades (Figure 1), mostly because of increasing fossil fuel emissions.  In the absence of strong emissions reductions, any draw down of the terrestrial sink will tend to further increase that annual uptick in concentration.

Silvaculturalists must have a long planning horizon and some have already begun to factor in vegetation/climate equilibrium in their tree planting prescriptions.  They use spatially-explicit projections of climate change from global and regional climate models, along with studies of tree species’ distribution based on historical climate.  Given the high certainty of long-term climate change, anyone who plants a tree in the coming decades and centuries  ̶  for wood production, climate change mitigation, or various other good reasons  ̶  should attempt to account for projected climate change over the lifetime of the tree.

Figure 1.  Mean annual carbon dioxide growth rate.  Bars are the decadal averages.   Image Credit NOAA.

The Green Pill

David P. Turner / August 18, 2023

The pill metaphor – taking a pill as a route to altered consciousness – has been around in popular culture for some time (e.g. The Jefferson Airplane song White Rabbit).  The metaphor was used as a central theme in the 1999 sci-fi film The Matrix.  In the movie, rebel leader Morpheus offers the hero Neo a choice of 1) a blue pill, which will put him back to sleep about the existence of the Matrix (a computer simulation of human existence in which all humans are unconsciously embedded), or 2) a red pill, which will keep him awake to the existence of the Matrix and allow him to step outside it and join the gang of revolutionaries who are trying to destroy the Matrix and save humanity.

The pill metaphor is catnip to social commentators, and many pill colors (and interpretation of those colors) have been expounded (you can search by pill color in The Urban Dictionary).

Here, I want to introduce my interpretation of a pill variant known as the green pill.  Taking the green pill awakens the partaker to the human predicament in terms of our relationship with the global environment.  Earth system scientists have shown that the human technological enterprise (the technosphere) is rapidly altering the Earth system – notably the climate and the biosphere – in a way detrimental to a sustainable human future.

Despite being a part of the technosphere, most humans are barely aware of it as a thing with structure and function.  As with the biosphere (the sum of all life on Earth), the technosphere has a throughput of energy (mostly fossil fuels at this point) and a cycling of materials (albeit poorly developed at this point).  Humans participate in the technosphere, but do not fully control it (e.g. our difficulty in reducing fossil fuel emissions).  Pervasive development of socio-ecological systems at all spatial scales, and continued work on building institutions of global environmental governance, provide a pathway to a better managed technosphere.

Taking the metaphorical green pill means becoming aware of yourself as a part of the technosphere, and accepting that big changes (non-violent in origin) are needed in our values and in how the technosphere operates (e.g. a global renewable energy revolution).

As more of us take the green pill, we will strengthen the movement to redesign the technosphere into  something more sustainable.

Extreme Weather Events, Social Tipping Points, and a Step-Change in Climate Change Mitigation

David P. Turner / August 12, 2023

Figure 1.  Annual additions of coal-fired electricity generation in recent years. Image Credit.

The rash of extreme weather events and associated impacts on humans around the world in recent years (especially 2023) is setting the stage for radical societal changes at the local and global scale with respect to climate change mitigation efforts.  One recognizable step-change in that direction would be a planet-wide cessation in the issuing of permits to build new coal-fired power plants.

Extreme weather events (droughts, heat waves, fires, and floods) are very much in the news recently everywhere on the planet.  Within the scientific community, these events are understood as part of normal weather variability, but also as attributable in part to on-going anthropogenic climate warming.  This year (2023) is proving to be especially prone to extreme weather events because of an extra boost of warming associated with an El Nino event

Globally, climate scientists suggest that 85% of people have suffered from extreme weather events that are partially attributed to climate change.

Social science research has shown that people respond markedly to their personal experience with weather events.  In the U.S., polls (2022) find that 71% of Americans say their community has experienced an extreme weather event in the last 12 months and 80% of those respondents believe climate change contributed at least in some measure to the cause.  In China and India, recent polls suggest strong awareness about the climate change issue and support for governmental mitigation policies. 

Admittedly, awareness of the issue is much lower elsewhere.  Some countries in Sub-Saharan Africa have relatively high proportions of inhabitants that have “never heard of” climate change. 

Nevertheless, billions of people around the world are making the connection between their personal experience of an extreme weather event and climate change.  Perhaps a new level of political support for mitigation efforts will emerge?

The concept of tipping points is common in the climate change literature, i.e. that distinct large-scale processes such as the melting of the Greenland ice sheet eventually reach a point where strong positive (amplifying) feedbacks are engaged and the process becomes irreversible (on a human timescale).  The concept has also begun to be applied to changes in social systems.  Given widespread changes in personal views about climate change, and perhaps appropriate societal interventions, particular societies and ultimately the global society may tip into a strong climate change mitigation stance.

A clear step-change in the global climate change mitigation effort would be a planet-wide cessation of permits for building new coal-fired electricity generating plants.  Coal emissions contribute about 40% to global fossil fuel emissions.

Tremendous momentum has already built up in that direction based on anti-coal environmentalism and the improving cost differential between coal power and other energy sources (primarily natural gas and renewables).  The U.S. and E.U. do not formally prohibit new coal plants but few have been built in recent years.

The World Bank, the International Monetary Fund, and China’s Belt and Road Initiative are no longer supporting construction of new coal-burning facilities and many countries have made commitments in their Nationally Determined Contribution statements that will require reduction in the burning of coal.

Remarkably, India has recently announced consideration of a policy to prohibit planning of new coal-fired plants for at least the next 5 years.

China is still permitting and building about 2 coal-fired power plants per week.  It is no doubt a big ask for China to adopt a no-new-coal-plants policy.  However, the country is suffering significantly from extreme weather events, from the negative effects of air pollution from coal combustion, and from the interaction of the those two factors.  And China leads the world in production of renewable energy. 

The autocratic style government in China is not conducive to bottom-up social tipping dynamics, but how the Zero-Covid policy was dropped is an interesting case study in social change.  Rumblings within the bureaucracy and multi-city protests appear to have influenced Xi Jinping to make the radical policy shift.  Given its massive contribution to the global total of new coal plants coming on line (Figure 1), if China stopped issuing building permits, the battle would be nearly won.

Two caveats to ending coal-fired power plant construction should be considered.  First is that the global demand for electricity will likely increase in the future because of 1) growth in the global population and increased per capita energy use in the developing world, 2) increasing demand from the conversion to electricity powered vehicles, and 3) wide application of AI technology.  To generate that energy from non-coal sources will be challenging but feasible.  The second consideration is the possibility of Carbon Capture and Storage, i.e. continuing to burn coal but capturing the associated CO2 emissions and sequestering them belowground.  This technological fix sounds good in theory but thus far decades of research and pilot studies do not support that it can be economically implemented at scale.

Across all of humanity, cultural differences tend to build silos around each society – especially differences in language, religion, and degree of technological development.  That isolation has diminished over the course of human development to this point, and with the advent of the Anthropocene we can begin to see humanity as a unified whole and as capable of working collaboratively  on global environmental change issues.

When the world does achieve consensus on ending the construction of new coal power plants, it will be a step-change in the global climate change mitigation effort.  It will also signal a step towards the emergence of a collective humanity, an indication that “we” can agree on, and implement, a path to a sustainable future on Earth.

Redesign of Earth’s Technosphere to Pass Through the “Great Filter”

David P. Turner / June 20, 2023

The universe is vast, and appears to be order-friendly.  Astrobiologists  ̶  who study the phenomenon of life in the universe   ̶  have thus concluded that life has likely arisen spontaneously on many planets.  The recurrent emergence of intelligent life by way of natural processes is also considered plausible.

Although astronomers began looking for signs of life and intelligence elsewhere in the universe in the 1960s (e.g. with radio telescopes), they have not as yet found a signal. 

That we expect planets inhabited by intelligent creatures to be plentiful, but have not encountered any, is referred to as the Fermi Paradox.  The explanation may lie simply in the  vast distances involved relative to the speed of light and how long we have been looking.  However, this silence also raises a question about possible factors that could constrain the development of exoplanetary, advanced-technology, civilizations. 

Astrobiologists have designated the constellation of factors that could prevent the evolution of a civilization capable of interstellar communication as “The Great Filter”.  The supposition here is that there are many crucial steps along the way, and only rarely would they all fall into place.  Some of the crucial roadblocks are the origin of life in the first place, the biological evolution of complex multicellular organisms, and the cultural evolution of technologically advanced societies. 

To help us think about patterns in planetary evolution, astrobiologists refer to the possibility of technospheres as well as biospheres.  A biosphere comes into existence on a planet when the summed biogeochemical effects of all living organisms begins to significantly affect the global environment (e.g. the oxygenation of Earth’s atmosphere around 2.5 billion years ago).  A technosphere comes into existence when the summed biogeochemical effects of all the material artifacts generated by a highly evolved (probably self-aware) biological species begins to affect the global environment (e.g. the recent boost in the CO2 concentration of Earth’s atmosphere).  Like a biosphere, a technosphere maintains a throughput of energy (such as fossil fuel) to power its metabolism, and a throughput of materials (e.g. minerals and wood) to maintain and grow its mass.

Earth’s biosphere has existed for billions of years and operates in a way that its influence on the global environment tends to keep the planet habitable (the Gaia Hypothesis).  Reconciling this mode of operation with Darwinian evolution is controversial, but Earth system scientists have proposed that components of the biosphere (i.e. guilds of organisms that perform particular biogeochemical cycling functions) have been gradually configured and reconfigured (by chance in combination with persistence of favorable states) into a planetary biogeochemical cycling system with sufficient negative feedback processes to maintain the habitability of the planet. 

In contrast to the biosphere, Earth’s technosphere exploded into existence quite recently and has grown wildly since its inception.  Few negative feedbacks to its growth have yet evolved.  Possible causes for truncated efforts towards a long-lived technosphere include factors such as apocalyptic warfare (a nuclear winter), pandemics, AI related take downs, and environmental degradation.  Any of these could qualify as the Great Filter. 

The most obvious problem with technosphere evolution on Earth appears to be the momentum of its early growth.  A Great Acceleration of technosphere growth, as seen on Earth in the last 100 years, is perhaps common in the course of technosphere evolution.  On a finite planet, exponential growth must end as some point, and a Great Transition must be made.  This transition is to a state that thrives even in a world of biophysical limits.  Given the quasi-autonomous nature of a technosphere, conscious reining in and redesign of technosphere metabolism may be necessary.

The key impact of overexuberant technosphere growth on Earth is rapid global climate change induced by greenhouse gas emissions.  A continued high level of these emissions could trigger a cascade of positive feedback mechanisms within the climate system that drive the global environment to a state fatal to the technosphere itself.  That process may turn out to be the distinctive manifestation of the Great Filter on Earth.

The transition to a mature (sustainable) technosphere on Earth will require 1) recognizing the danger of rapid environmental change, 2) understanding what must be done to redesign the technosphere, and 3) organizing collectively (globally) to carry out a program of change.

Earth system scientists have gotten quite good at simulating the causes and consequences of global climate change.  Thus, the scientific community recognizes the danger of uncontrolled technosphere growth and understands what must be done to avoid a climate change catastrophe.

But deliberately pushing our current technosphere through the sustainability phase of the Great Filter will require the difficult political work (within and between nations) of changing values and better organizing ourselves at the global scale.

If humanity does ever encounter extra-terrestrial intelligence, I imagine that it will stimulate global solidarity in an “us vs. them” context, and perhaps strengthen our willingness to work together on issues of global sustainability and defense.

As long as we do not encounter extra-terrestrial intelligence, we must face the enormous moral responsibility to conserve and cultivate our biosphere and technosphere as possibly unique, hence supremely valuable, cosmic experiments.

Earth Day 2023 and Global Solidarity

David P. Turner / April 16, 2023

Earth Day 2023 (April 22) is the 53rd anniversary for this annual gathering of the global tribe.  Historically, it has been an opportunity to protest the decline in environmental quality and to envision a sustainable relationship of humanity to the rest of the Earth system.

So, let’s review three environmental trends of particular concern in 2023 and three pointers to the possibility of a sustainable Earth system.

Three concerns.

1.  2023 is shaping up to be an El Niño year.  Ocean circulation in the equatorial Pacific Ocean will slow, which means less heat removal to the ocean interior by downwelling water in the western pacific and less delivery of cool upwelling water in the eastern Pacific.  Global mean temperature will tick up a bit beyond the usual expectation.  There is speculation that 2023 will be the warmest year on record.

2.  Sea ice extent will continue to decline at both poles, which is part of the snow/ice albedo positive feedback to global warming.

3.  Greenhouse gas concentrations will continue to rise.  The annual increase in methane concentration is especially worrisome because the increase has been relatively large in recent years, a consequence of rising emissions from both the global energy sector and biosphere sources.

Three trends to be hopeful about.

1.  The International Energy Agency recently reported that 2023 will mark a step-change upward in the public and private financing available to support the global renewable energy revolution.  The official theme of Earth Day 2023 is “Invest in Our Planet”.

2.  The proportion of land and ocean area in some sort of biodiversity protection status continues to rise.  A 2022 UN biodiversity conference set a goal of 30% by 2030.

3.  Stratospheric ozone continues to regenerate in response to the global regulatory process associated with the Montreal Protocol.

There are endless issues within countries and between countries for humans to argue and fight about.  But recent anthropogenically-driven changes in the global environment are something we all have in common, and something that must be addressed collectively.

In the near term, the growing incidence of extreme weather events associated with anthropogenic climate change negatively impinges on the quality of life of a vast number of people around the planet.  On a decadal time frame, sea level rise will come to displace hundreds of millions of people.  At the scale of a century or more, on-going climate change may set off a cascade of positive feedback mechanisms that will drive the Earth system to a new state inimical to an advanced, high technology, global civilization (the Icarus Scenario).

There are many impediments to becoming a global “we” that will work collectively on global environmental change issues.  But Earth Day, as the largest recurring secular celebration in the world, is an occasion to think anew and commit to opportune joint initiatives.

We’re Going to Need a Bigger Power Supply and It Better be Renewable

David P. Turner / March 1, 2023

Developing and maintaining AI-based conversational beings ̶ such as ChatGPT ̶ will significantly increase global energy demand. In the interests of global sustainability, that additional power must be from renewable sources. Original graphic (Monica Whipple and David Turner).  Image Credits: Circuitry, Wind Farm, Solar Panels, Pylons.

When the sheriff character in the original “Jaws” movie first sees the giant shark, he exclaims to the captain “You’re gonna need a bigger boat”.

An analogous statement regarding the energy requirements associated with the coming proliferation of conversational virtual beings (based on Artificial Intelligence) is that the technosphere is going to need a bigger power supply.

By virtual beings I mean all the digital, language-capable, denizens of the emerging metaverse (broadly defined), including chatbots (like ChatGPT), AI-assisted search engines (like Perplexity AI), and AI-based residents of Meta’s visor-enable virtual reality world.  Coming down the line are speaking holograms, and holodecks (as in Star Trek).

The process by which these advanced digital creatures learn to speak is based on development of neural networks that are trained with a large body of textural information (like Wikipedia, books, and an array of content available on the Internet).  Training means determining statistical relationships between the occurrence of different words in the training text, which the algorithm then uses to formulate a response based on keyword inputs (queries).

Training a large language model such as ChatGPT requires a hefty input of computing power because it involves extensive trial and error testing.  Chatbots affiliated with AI-assisted Internet searches use not just a pre-trained language model but also integrate the search output into their responses.  This kind of processing will be energy demanding (perhaps 5 times greater than for a standard search), which will add up considering the billions of searches made per day.

If these virtual beings were only going to be used by a minority of people (such as now visit Meta’s colony in the metaverse), the power draw would be minor.  But, very likely, their seductive appeal will be so great (albeit with an occasional hint of menace) that they will become a standard feature of ordinary life.  Just in the field of education, there is vast potential for inspiring and informing students using dialogic Chatbots.

Efficiency in training and operation of these virtual beings will no doubt increase, but industry specialists see a booming rise in electrical energy demand as their use expands.  Note that electrical power demand for electric vehicles, and to power the broader trend towards electrification of heating and industry, will also rise significantly in the coming decades (a good thing!). 

The overshoot model argues that global energy consumption should be reduced rather than expanded because of the many negative environmental externalities (unaccounted for damages) caused by energy production  ̶  from both fossil fuel and renewable sources. 

However, at least for electricity, that seems unlikely given the burgeoning energy demand in the developed world noted here, and the aspiration to raise standards of living in the developing world.

Since 66% of global electricity production is still based on combustion on fossil fuels, any increase in electricity consumption will tend to result in more greenhouse gas emissions and more societal problems with climate change.  The obvious conclusion in that new energy demand must be met by nonfossil fuel sources like hydro, wind, solar, geothermal, and nuclear fission.  Companies such as Google, Microsoft, and Meta that are building the metaverse will experience huge increases in energy consumption in the near future; they should be held to their commitments to run on carbon neutral power sources.

New energy technologies that could contribute to a clean global power supply in the coming decades include geologic hydrogen and solar energy from space.  These sources, however, will require long-term investments in research and development.

The global renewable energy revolution is off to a good start and has a bright future, but it will require steady political pressure to 1) stop building new fossil fuel burning facilities, 2) replace aging fossil-fuel-based infrastructure with renewable sources, and 3) build new renewable energy sources that can accommodate the increasing demand that is surely coming.

Commentary on “The Letter: Laudato Si Film”, and “Laudato Si” (the encyclical)

David P. Turner / January 23, 2023

Pope Francis issued an encyclical (Laudato Si) in 2015 about “care for our common home”.  The document discussed a wide range of global environmental change topics, notably climate change and loss of biodiversity.  It aimed to provide a moral rationale for simultaneously addressing the issues of global environmental change and human inequity.  The encyclical runs to nearly 200 pages and is not a light read.  Perhaps to make its message more accessible, the Vatican recently produced and released (October 12, 2022) a related video (The Letter: Laudato Si Film), clocking in at 81 minutes.

The encyclical was released just prior to the United Nations Framework Convention on Climate Change COP21 meeting that was held in Paris.  The product of that meeting was The Paris Agreement, which is widely perceived as a significant step towards mitigating global climate change.  Considering that there are 1.3 billion Catholics who ostensibly consider the pope infallible, the encyclical may well have strengthened global political will to seriously address the climate change issue.

The film is a very different vehicle from the encyclical, leaving behind the encyclical’s more controversial aspects (discussed below) and presenting an engaging narrative about global change with good visuals and music.  The premise of the film is that the Pope invites a set of 5 people from widely different backgrounds to Rome for a “dialogue” about the encyclical.

The five participants included the following.

1.  A poor black man from Senegal who is considering an attempt to migrate to the EU because of the deteriorating environment in his home country.  He represents the billion or so people expected to be displaced by climate change this century.

2.  An indigenous man from Brazil whose forest homeland in the Amazon Basin is under siege.  He represents forest dwellers throughout the tropical zone who are losing their homes to rampant deforestation.

3.  A young woman from India.  She represents the voice of a younger generation who will be forced to deal with the massive environmental change problems caused by their elders (intergenerational inequity).

4.  A man and a woman from the U.S. who are scientists working on monitoring and understanding coral reef decline.  They represent the community of research scientists trying to understand climate change impacts and what to do about them.

Each participant is shown in their home environment receiving a letter of invitation from the Pope.  The film then documents their experiences in Rome, including discussions amongst themselves and with the pope.

The film was engaging and had a positive message about the need for solidarity across all humanity in the face of threats from climate change and loss of biodiversity.

However, I did have some concerns.

First was that the film seemed to be more about the victims of global environmental change (both human and nonhuman) than about the solutions.  The participants were certainly sincere, and helped put a human face on the challenges ahead; but little was said about the personal changes and the political realities involved in transitioning to global sustainability.

Second was the emphasis on climate change as the sole driving force in the current surge of migration.  Climate change is indeed driving international migration but a host of other factors are of equal or greater importance, including civil war, overuse of local natural resources, and gross defects in local governance.  If indeed a billion people will potentially be displaced by climate change in this century, they can’t all migrate.  Alternatives to migration include foreign aid for adaptation, and aid to improve local educational opportunities that would help train citizens for local economic activity and help limit population growth (the fertility rate in Senegal is 4.3 births per woman).

Third was that the film may point viewers towards reading the actual encyclical, which has inspired much more commentary  ̶  both positive and negative  ̶  than the film.

The proclamations of the pope usually do not draw much attention from the scientific community, but in the case of the Laudato Si encyclical, the science of global environmental change is front and center.

As I started reading the encyclical, I was surprised because the tone sounded as if it were written by an environmental science policy analyst rather than a religious leader (apparently there was a ghost writer).  The scientific causes of climate change and biodiversity loss were reasonably explained, and it was refreshing to see the “dominion” over the Earth given to humanity by God presented more in terms of responsibility to conserve environmental quality than as a license to exploit limitless natural resources.  The intrinsic value of all species, independent of their utility to humans, was recognized.  When the text veered into explaining the Christian belief system (e.g. the Holy Trinity), it lost cogency from an Earth system science perspective.

The encyclical was well received by scientific authorities in some cases, perhaps because the Pope broadened the usual rationales for caring about climate change and biodiversity loss to include the moral dimension.  Wealth-based inequity (relatively wealthy people have caused most of the greenhouse gas emissions but it is relatively poor people who will suffer the greatest impacts) and intergenerational inequity (recent generations have caused most of the greenhouse gas emissions but future generations will suffer the greatest impacts of climate change) are  clearly moral issues.

Critiques of the encyclical have referred to its limited regard for the full suite of dimensions (technical, political, and economic) needed to address global environmental change.  The encyclical comes across as hostile to the “technocratic paradigm”, suggesting some technofixes will induce more problems than they solve.  There is much emphasis on reducing excess consumption.  Realistically though, there must be a revolutionary change in technology towards renewable energy and complete product recycling.  Likewise, beyond calling for a stronger climate change treaty (as the Pope did), we must have stronger institutions of global environmental governance, and new economic policies that prioritize sustainability.

The section of the encyclical about population control was especially provocative.  The pope took issue with calls for limiting population growth for the sake of the environment, a position  consistent with formal Catholic doctrine against contraception.  This view rings false, however, because of the contradiction between saying that Earth’s natural resources are limited (as stated several times in the encyclical) and that all humans deserve a decent quality of life (which inevitably consumes natural resources), while at the same time maintaining that high rates of population growth in developing countries are not an issue.  In contrast, the recent World Scientists’ Warning of a Climate Emergency 2022  called for “stabilizing and gradually reducing the human population by providing education and rights for girls and women”.  Ehrlich and Harte also point out that unchecked population pressure on food supply and natural resources pushes development into ever more vulnerable ecosystems, and fosters ever more inegalitarian forms of government.

Pope Francis deserves credit for bringing attention to the moral questions raised by anthropogenically-driven global environmental change.  Our contemporary materialistic and instrumental value system has proven to be unsustainable and should indeed be influenced by values based on respect for the natural environment, as well as values derived from human solidarity.  The Laudato Si encyclical and film (along with associated praise and critique) are contributing in a positive way to the ongoing process of cultural evolution, which has now begun to operate at the global scale.