Aspirations for a Just Earth System as well as a Safe Earth System

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David P. Turner / November 19, 2024

Recent commentary on paths to global sustainability has advocated for Earth system justice (ESJ), specifically for an Earth system that is just as well as safe.

A safe Earth system is one in which both the biosphere and the technosphere thrive.  Current threats to the biosphere and technosphere come in the form of well-documented anthropogenic impacts on Earth’s energy balance, the global biogeochemical cycles, and the biota.  Earth system scientists have identified a set of planetary boundaries – such as an atmospheric CO2 concentration and associated increase in global mean temperature – beyond which Earth system characteristics such as climate will be destabilized, thereby putting at risk the welfare of both humans and other species.

A just Earth system is more difficult to define.  Historically, justice has largely been concerned with how people treat each other.  The formulation of the Universal Declaration of Human Rights was an outstanding achievement in the struggle for social justice.  However, the advent of the Anthropocene era has generated new questions about equality and fairness.

One of the key observations relevant to defining ESJ is that the people most impacted by climate change (e.g. impacts from a greater frequency and intensity of extreme weather events) are often not the people who have made the biggest contribution to causing climate change.  The basis of this distributional inequity is that relatively wealthy people usually have high per capita greenhouse gas emissions, but their wealth also buffers them from the consequences of climate change.  To account for this differential exposure, Earth system scientists have begun to estimate just planetary boundaries that would protect even the relatively vulnerable.

While distributional inequity can be considered in the current time period (intragenerational), we must also consider inequity through time (intergenerational justice).  Recent generations have greatly benefited from fossil fuel combustion, but it is future generations that will mostly pay the costs as climate disruption becomes manifest.  In a just world, each generation would leave the planetary life support system in as good or better a condition than the condition in which they inherited it.  Following that principle would require much larger  investments in greenhouse gas emission mitigation than are currently being made.

The Earth system justice concept also raises the issue of interspecies justice.  What give Homo sapiens the right to drive other species extinct?  Since we have clearly entered the Anthropocene era (with its associated 6th Great Extinction), humanity now has a responsibility to care for other species, and indeed for the biosphere as a whole.

Achieving ESJ is a daunting challenge because, even when considering just the biogeochemical aspects of Earth system function, the technical and environmental questions about how to address global environmental change issues are already complex.  To add the related issues associated with intragenerational justice, intergenerational justice, and interspecies justice makes finding answers even more difficult ( e.g. the hydrologic cycle as it relates to meeting basic human needs while factoring in protection of aquatic ecosystems).

There are policies that could help make the Earth system safe but would not make it more just, such as appropriating land from indigenous people to create carbon sinks.  Likewise, there are policies that could help make the Earth system more just, but would not make it safer, such as building coal burning power plants in developing countries that provide relatively cheap and reliable energy but also emit large quantities of greenhouse gases.  So, although the objective of reducing global greenhouse gas emissions is straightforward, the questions of who has responsibility, how to go about it, and where to prioritize the efforts, are more nuanced.

Given the many trade-offs among safe planetary boundaries and just planetary boundaries, political decisions must be made.  In the political realm (at least when there is some semblance of democracy), there is generally both a forum at which the stakeholders on any given issue can express their positions, and a societal decision-making mechanism that attempts to account for, or reconcile, the various interests.  In the case of climate change mitigation, we are fortunate that many mitigation policies can also serve to promote social justice.  Investments to manage land for the purposes of carbon sequestration and biodiversity conservation could also serve to maintain homelands for vulnerable Indigenous people.  Investments in education and provision of family planning services improve quality of life, and also serve to tamp down population growth and hence total greenhouse gas emissions. 

An important practical rationale for addressing inequity as part of addressing global environmental change is that impoverished people may be pushed to live in marginal environments and will exploit any available natural resources to survive.  They don’t have the luxury of worrying about whether the environment is being degraded.

More generally, many global environmental change problems require global scale solutions. That means humanity as a collective must address them.  A major problem with respect to inequity is that it erodes feelings of solidarity.  Inequity prevents the organization of humanity as a “we”.

Achieving a safe and just Earth system will require leaders who understand the issues elaborated here, as well as the building of Earth system governance institutions that allow relevant policies to be debated and promulgated both nationally and globally.  The Great Transition to a sustainable global civilization needs technological advances like a renewable energy revolution, but also efforts to mitigate multiple forms of injustice.

Deglobalization and Reglobalization of Wood Supply and Demand

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David P. Turner / August 20, 2024

Wood is an iconic renewable resource  ̶  trees grow, wood is harvested, new trees are planted, and more wood is produced.  On a managed forested landscape growing trees with a 100-year time to maturity, a forester can maintain a sustained yield of wood by harvesting and replanting patches totaling 1% of the total area each year. 

However, not all commercially processed wood comes from sustained yield forests.  Cutting of previously unlogged natural forests (i.e. primary forests) in the boreal and tropical zones is still widespread.  Removal of the large trees in tropical forests is often followed by land use change. 

Natural forests (currently about one quarter of the total forested area globally) are valued for multiple ecosystem services  ̶  notably conservation of biodiversity, provision of fresh water, and carbon sequestration.  They also provide a home to forest-dwelling indigenous people around the world.  Thus, reducing the loss of tropical natural forests to logging is a high conservation priority.

Like many natural resources, wood supply is heavily influenced by economic globalization.  Under neoliberal free trade economics, wood enters the global market based primarily on the cost of production.  If manufacturers can obtain logs relatively cheaply from first entry of natural forests rather than from sustainably managed forests, they are economically compelled to do it.  Pushback against this ideology is coming from regulators, NGOs, and advocates for indigenous people’s rights.

Global Wood Demand

To determine if the total global demand for wood could be sourced from sustainably managed forests, let’s first examine the magnitude, geographic pattern, and trend in wood demand.

Wood is commercially processed in the form of roundwood, with predominant uses of commercial wood as construction materials, paper/packaging, and biomass energy.  The projected long-term trend is for continued annual increases (1-3%) in global roundwood demand. 

Current global roundwood consumption is on the order of 4 billion cubic meters per year.  The highest wood consuming country is the U.S.  Second is China, however, much of China’s consumption is imported, moves through a value-added product chain, and is exported.  China is the largest importer of unprocessed logs and the largest global producer of plywood and paper.  Other historically large consumers of roundwood include several countries in the EU.  New sources of demand are emerging in developing countries.

Use of wood in buildings will increase in coming decades driven by expansion of the housing sector (more people and higher standards of living).  Wood will be a preferred component in new construction because of both advances in materials science, and the carbon benefits of substituting wood for steel and concrete.

Demand for paper and cardboard is rising 3-4% per year, in association with its soaring use in packaging.

Wood demand for combustion in biomass energy power plants is also on the rise (~5%/yr) mostly because emissions from biomass energy power plants are considered carbon neutral in some domains (e.g. the E.U.). 

Global Wood Supply

Roundwood comes into the global production stream from a great variety of sources.  Besides unsustainable cutting in natural forests, we might identify a continuum of sustainable forestry management approaches along an axis based on the importance of wood production relative to other ecosystem services.  The continuum extends from plantation forestry, through modified natural forests, to undisturbed old-growth forests.

Supply from Sustainably Managed Forests

Boreal Zone

In Scandinavian countries, a large proportion of wood removals is from previously harvested and replanted boreal forests.  However, the total volume produced is relatively small. 

Temperate Zone

After hundreds to thousands of years of human occupation, the temperate zone has relatively little natural forest remaining.  In the temperate zone, softwood species (conifers) are generally managed by clear-cutting and replanting, whereas hardwood species are usually harvested by selective cutting.  Managed forests in the temperate zone are primarily in European and North American countries.  New Zealand, Australia, Chile, and China have also developed extensive areas of planted forests.

Tropical Zone

Sustainable management of tropical forests based on selective cutting with suitably long re-entry times is possible, but not yet widespread.  Plantation forests in the tropical zone grow relatively fast and thus have a short rotation time (and faster return on investment).  The area of planted forests in the tropics is increasing.  

Supply from Natural Forests

Most of the wood production in Russia and Canada is from natural forests.  In Russia, much of this logging is essentially a “mining operation”, with corresponding negative impacts on biodiversity.

Logging of tropical hardwoods in natural forests is extensive in most regions where tropical moist forests grow.  After tree removals, the land is commonly used for grazing, commercial agriculture, or subsistence agriculture.  In Indonesia, deforestation is often associated with conversion to palm oil plantations.  In Central Africa and parts of the Amazon Basin, high value trees are removed for export and the land is left as secondary forest.

Much of the wood from cutting in tropical natural forests is exported to manufacturing centers like China (about two thirds) and the EU. 

Because of the rapidly increasing area of plantation forests, the proportional contribution of natural forests to the global wood supply is declining.  However, completely shutting down that wood source for conservation purposes would significantly diminish global wood production.  A first order analysis by the World Wildlife Fund (WWF) suggests that the current global wood demand could largely be met by sustainable forestry (i.e. without cutting in primary forests) if about half of the world’s forests were used in wood production (the rest being devoted to provision of other ecosystem services.  Projected increases in wood demand could not be met with the land base available for wood production. WWF proposes a reduction in per capita wood consumption, but a  more likely outcome would seem to be increased per unit area productivity associated with more intensive forest management.

 The Role of Forest Certification

Consumers of forest products increasingly insist on evidence that the associated wood was harvested sustainably.  Consequently, there is an growing interest in sustainable sourcing within the forest products industry.

A key to ending the supply of wood from first entry into natural forests is forest certification.  Buyers and sellers of wood can use certification as proof that their business practices are not contributing to deforestation or forest degradation. 

Certification authorities are usually nonprofit, nongovernmental organizations.  Forest management on a particular piece of land is certified based on management practices, including harvesting and replanting.  Certification is also applied to wood itself in various stages of the supply chain.

Major retailers like Home Depot and IKEA have made concerted efforts to provide certified wood.  Approximately 13% of the global forestland is certified, and the trend is upward.

A significant cost premium must be absorbed by forest managers, manufacturers, retailers, and consumers when managed land or wood products are certified.  The willingness to pay that premium depends on educating wood consumers about issues with forestry practices.  At the national level, policies supporting restriction of uncertified wood imports are becoming more common.

Chinese manufactured wood exports are sometimes routed through Vietnam and Malaysia to subvert attempts by companies in the EU and US to accept only certified wood products.  A promising technology for enforcement of certification labeling involves tracing the origin of logs or wood by use of genetic information.

Deglobalization and Reglobalization

Global industrial roundwood demand is projected to rise by 50 per cent or more by 2050.  To reduce loss of natural forests in the tropical zone, there must be a deglobalization of wood imports from tropical natural forests.  This loss of logs (much of it illegal in any case) could be compensated for to some degree by increasing production from certified planted forests in the boreal, temperate, and tropical zones.  Obviously, this new wood production should not come by way of converting intact primary forests to plantations. 

Currently only 11% of the global forested area dedicated to wood production is plantation forests, yet that land provides around 33% of current industrial roundwood demand.  Our world is going to need more high-yield forest plantations, along with the international trade that serves to match wood supply and demand (reglobalization).

Conclusion

The technosphere consumes a vast quantity of wood; where it comes from and how it is harvested matters greatly to the possibility of global sustainability.  If unsustainable logging in primary forests was shut down, and compensatory increases in wood production were created from planted forests, sustainably managed forests could conceivably provide the current global demand for wood.  Certification of managed forests and forest products is a key mechanism for halting entries into remaining natural forests, which better provide a variety of other ecosystem services.

The Anthropocene is Not Formally a Geological Epoch  ̶  So, What is It?

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David P. Turner / April 3, 2024

A surprising outcome emerged from the March meeting of the Subcommission on Quaternary Stratigraphy (within the International Union of Geological Sciences).  The surprise came in the form of a vote regarding the official status of the Anthropocene concept, with a majority of the subcommission members voting against a proposal to identify the Anthropocene as a new geological epoch.

The term Anthropocene was originally inspired by the observation that the impacts of the human enterprise on Earth’s environment  ̶  notably a rise in the atmospheric CO2 concentration  ̶  have begun to rival those of the background geologic forces.  Since divisions of the geologic time scale are generally associated with major changes in the global environment, naming a new epoch was a reasonable suggestion.

The formal proposal to do so came from the multidisciplinary Anthropocene Working Group (AWG), which has deliberated on the issue for the last 14 years.  The AWG proposal specified that the Anthropocene be named a new epoch, with a beginning point in the early 1950s.  Its stratigraphic marker was to be a layer of chemical residues from post-World War II nuclear weapons testing. 

The Vote

The vote against designating the Anthropocene as a new Epoch was a surprise because the proposal had been made with a strong scientific foundation and had a lot of support.  The decision against the proposal was not because the Anthropocene is geologically insignificant, but rather because the Anthropocene concept is highly significant to many disciplines besides geology.  In the last 20 years, the concept has received widespread attention in both academia and popular media.  Indeed, the term has taken on a life of its own, a life outside the staid world of Quaternary Stratigraphy.

The term Anthropocene has come to signify a rupture in human history  ̶  the end of a time when the biophysical environment was mostly a background to the march of human progress.  The rupture is evident from a suite of global indicators, ranging from oil consumption to the rate of deforestation, that all began rising dramatically in the last 100 years.  The word Anthropocene now has broad cultural significance; it implies that humanity has acquired a new responsibility to self-regulate, or face its own demise from a self-induced inhospitable environment. 

The negative vote within the subcommission was also based on a more technical issue about whether, considering that humans have been altering the environment at many scales for many thousands of years, the beginning of the Anthropocene Epoch could be narrowed down to the early 1950s.

An alternative proposal, with considerable cross-disciplinary support, is to designate the Anthropocene a geologic “event”.  This term is used in the geosciences to reference a wide variety of Earth system changes or transformations.  Designating something as an event does not require the kind of formal approval process associated with designating an epoch.

The Scope of the Anthropocene Event

Despite this quasi-downgrade to Event status, the Anthropocene has really just begun and will ultimately have a massive impact on the Earth system.  The Anthropocene Event, as we will call it here, will eventually push the global mean temperature up 2-3 oC or more, a range associated with the early Pliocene Epoch 3-5 million years ago (Figure 1).  Because of human influences on the atmosphere, Earth may well miss its next scheduled glacial period (as prescribed by the Milankovitch solar forcings).  

The graphic is a time series plot going back 5 million years ago showing the trend in global mean temperature.

Figure 1.  The geologic record of global mean temperature, with projections to 2100.  The x-axis units differ by panel.  The graphic is adapted from work by Glen Fergus.

What is also quite extraordinary is that the Anthropocene Event is concurrent with the origin of a whole new Earth system sphere – the technosphere.  This term refers to the accumulation of human artifacts  ̶  including buildings, transportation networks, and communication infrastructure  ̶  that now cloaks the surface of the Earth.

From an Earth system science perspective, the parts of the Earth system are its spheres, i.e. the lithosphere, atmosphere, hydrosphere, cryosphere and biosphere interact with each other over geological time to determine the state and dynamics of the Earth system.

The biosphere (defined by geochemists as the sum of all life on Earth) is of particular interest here.  The biosphere did not exist early in Earth’s history, but after the origin of life and its proliferation around the planet, the impacts of the biosphere on Earth’s energy flow and chemical cycling became profound (e.g. the oxygenation of the atmosphere).

Now the technosphere, a product of human history, has joined the biosphere as an active force on the surface of the planet.  Like the biosphere, it has mass and uses energy to maintain itself and grow.  It has become a significant factor in the global biogeochemical cycles.  Unlike the biosphere, the technosphere has not been around long enough to become well integrated with the rest of the Earth system, e.g. it largely does not recycle its own waste. 

During the Anthropocene Event, the technosphere could be destroyed or self-destruct by various mechanisms, or could come into a stable state of sorts with the rest of the Earth system, in which case it might last quite a long while. 

The Role of the Anthropocene Event in Cultural Evolution

Transition to global sustainability will require the emergence and evolution of a global culture, i.e. a globally shared set of beliefs and practices.  The Anthropocene Event is a concept that can help anchor a robust integration of human history and Earth history.

Transdisciplinary investigations covering a wide range of issues associated with managing the human enterprise on Earth  ̶  including  aspects of the social sciences, humanities, and biophysical sciences  ̶  may hinge on having this shared reference point. 

The Right Call

In light of the need for broadly unifying concepts related to global environmental change, I think the geologists made the right call.  The Anthropocene has become a politically potent idea and deserves the widest possible attention in the domains of scholarship, education, entertainment, and advocacy.

This post was featured on the Millennium Alliance for Humanity and the Biosphere (MAHB) web site.

Positive Feedback Loops to Propel the Sustainability Transition

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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

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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

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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

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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

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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

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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”

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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.