This installment continues the story of my collaboration (along with fellow scientist Pavel Šamonil) with Czech artist Petr Mores in combining visual art and science to tell the story of landscape evolution of forests, topography, and soils in the Šumava Mountains, Czech Republic (part 1; part 2). Here, I take a crack at brief narratives for four key parts of the story—trees, water, soil, and landforms. All the accompanying illustrations are from Mores—closeups are detail from his Biogeomorphological Domination piece, shown and analyzed in parts 1 and 2. Others are from preparatory work Petr did for that piece, and other examples of his paintings and drawings in the forests of the Czech Republic.

Tree story (general time scale: decades)

The tree story begins with establishment of a seedling, which is determined by production of seeds (cones) by an adult spruce, dispersal, predation, and the edaphic conditions where it alights. These include soil moisture and drainage or wetness, soil nutrients, and the presence of “nurse” logs. As compared to other trees, for Norway Spruce (Picea abies) soil drainage and nurse logs are especially important. Spruce does better on wet sites than competing trees, and recruitment often occurs on decaying spruce logs.

Tree growth, health, and reproduction are also influenced by edaphic conditions, competition from other spruce or other species, effects of pests or disease, and disturbances. These are influenced by episodic or time-dependent factors of weather and climate, and events such as droughts, windstorms, and fires.

A healthy, growing tree, in addition to getting taller and thicker, spreads roots with a predominantly lateral, disk-like root architecture, producing a basal mound and possible root mounds associated with large lateral roots. The tree continuously uses water drawn from the soil, transpires water vapor back to the atmosphere, and disperses water through the soil along living roots and channels or former roots. The tree also produces litter (needles, twigs, etc.), building a litter layer and adding soil organic matter.

Tree death has three major pathways. Trees that die in a standing position or are broken (trunk breakage) eventually leave a stump that decomposes. These may leave a depression as the wood rots and soil displaced by the tree to create a basal mound subsides. In some cases, a distinct stump hole is formed. A second pathway is harvesting, which has the same topographic effects, but no lying trunks or large logs.

Uprooting is the third pathway. An uproot pit is formed immediately by the soil and regolith pulled out with the rootwad. As material falls off the rootwad and the tree decomposes, an uproot mound forms adjacent to the pit. The pit-mound topography and its local effects on water flow, soil moisture, and organic matter accumulation influence edaphic conditions and seedling establishment.

The uprooting and standing death/breakage paths both produce lying trunks on the ground. These may become nurse logs for seedling establishment. The local mounding (from wood decomposition, moss growth, and sometimes sediment trapping) and nutrient supply from decomposition influence edaphic conditions and seedling establishment.

Water story (general time scale: hours to days)

A raindrop or snowflake falling towards the ground begins the water story. The drop either falls directly on the ground surface, or is intercepted—that is, lands on or is caught by plants. This intercepted water, if it is not evaporated, reaches the ground by drip from leaves/needles, or stemflow along the trunk or stem.

Once at the ground surface, either directly or via a plant, the water may infiltrate (soak into the soil). If it does not, it either remains on the surface as depression storage (e.g., puddles), or flows downslope as surface runoff or overland flow. Water in depression storage may will eventually evaporate, infiltrate, or possibly become part of surface runoff if puddles overflow.

Water that infiltrates—some flowing along plant roots and root channels--is available for plant uptake and use and some will be transpired to the atmosphere as water vapor. Before plant use or transpiration, infiltrated water may be stored as soil moisture in vegetation litter or mineral soil. Percolation as matrix or macropore flow within the soil and regolith, or as flow along roots, may deliver H₂O to groundwater.

Subsurface water stored as soil moisture is subject to root uptake by plants, and (in ground water, macropores or conduits, or saturated soil), lateral downslope throughflow. Surface runoff is governed by topography, flowing away from higher local elevations and water-shedding peaks or mounds (such as basal mounds of trees and uproot mound), and toward depressions such as intermound swales, uproot pits, stumpholes, and channels.         

The geomorphic and pedologic work of water as it moves through or is stored in the landscape includes weathering of bedrock, rock fragments, and soil; erosion, transport, and deposition of sediment; transport of solutes in surface runoff or groundwater, and translocation of material within soils and weathering profiles.

Soil story (general time scale: decades to millenia)

The soil story commences with the inherited geological parent material, either in intact bedrock form, or as rocky debris produced by glacial and periglacial processes. This is acted on by physical, chemical, and biological processes—particularly those associated with climate, water movement, microbes, plants, and gravitational forces.

The parent material is disintegrated and decomposed by weathering. This includes physical or mechanical weathering (mainly freeze-thaw and hydrofracturing or frost weathering), and chemical weathering, such as redox (oxidation and reduction) processes, hydrolysis, and dissolution. Biological weathering may be direct, via “rock-eating” organisms such as some lichens and cyanobacteria, and uptake of minerals via plant roots. Biota also facilitate (and in some cases are necessary for) many types of chemical weathering; mainly microbes (bacteria and fungi). Weathering continues to affect weathered rock and soil.

Organic matter is added to the soil by decomposition of dead organisms or parts thereof, especially plant litter and dead vegetation. Among decomposing organisms, microbes are particularly important. Living fauna also transform organic matter via consumption followed by defecation and other excretions.

Mass is translocated within soils and weathered material by water movement—this is largely gravity driven, but rising water tables and evapotranspiration can drive upward movement. The direction of translocation is strongly influenced by physical properties of the soil (e.g., permeability, porosity) and their spatial variations, and by macropores and roots. Net movement is generally downward, but water flow, and thus translocation, can occur in any direction. Biological translocation also occurs via burrowing, tunneling, mounding, and digging by fauna. Translocation may be dominantly physical (for example lessivage, where smaller particles are washed between larger ones; gravitational settling of rock fragments) or chemical (e.g., where material is dissolved at one location and precipitates at another; or food is consumed at one site and waste is excreted at another, such as by earthworms).

Physical biological translocation processes are also forms of bioturbation (physical disturbance or soil mixing). These also include displacement by tree uprooting and by subsurface and ground-level components of plant growth.

Additions to the soil include sediment deposition at the surface (via fluvial, mass wasting, or aeolian processes), and organic matter. Losses include surface or subsurface erosion, mass wasting, leaching (removal of dissolved material in runoff or groundwater), and loss of organic matter via decomposition and fire.

In general, over time soils will proceed from thin covers of minimally altered parent material or organic matter to more highly altered, thicker, and more organized (often called mature) states. Soil development may occur along these progressive pedogenetic pathways, or regressive pedogenetic pathways toward thinner, less organized and developed soils. Progressive and regressive trends are both reversible, and many soils reflect the past influences of both.

Topographic story (general time scale: centuries to millenia)

The “time zero” for topography in this case is the latest Pleistocene. The story starts on a template of broad scale topography inked to lithology, structure, tectonics, and geologic history. Weathering (as described in the soil story) acting on these inherited materials produces transportable material, which moves mainly via mass wasting, fluvial processes, and bioturbation.

As weathering proceeds, the landscape is sculpted by erosion, sediment transport, and deposition. Glacial and periglacial processes were important just before and at the very beginning of the story. Slope (mass wasting) and fluvial processes have dominated since.

A fluvial system of rivers and streams developed, with channels occupying inter-ridge valleys and glacially carved troughs. Channels extended upslope, but only on a limited basis. Runoff from summit areas and upper slopes is not well-connected due to the complex local and microtopography. Subsurface flow, with a strong lateral component (again strongly affected by the trees), dominates over surface runoff in these areas. Runoff is generally slow and drainage relatively poor, maintaining moist conditions in the landscape.

Locally, spatially complex hummocky microtopography developed, largely via the biogeomorphic effects of trees, via basal mounding (and intermound swales), tree uproot pit-mounds, and other effects. The local details of this topography are dynamic, but the overall surface complexity is maintained by biomechanical effects of trees and the low connectivity of surface and subsurface runoff.

In the first part of this thread I tried to show how artist Petr Mores collaborated with Pavel Šamonil and myself to depict certain landscapes of the Šumava Mountains in central Europe to show interactions among topography, geology, soils, and vegetation. In this installment I’ll get a bit more specific with respect to the story we are trying to tell.

The short version of the story is that Norway spruce (Picea abies) modifies its environment (ecosystem engineering), mainly through biogeomorphic effects, in a way that largely controls the development of landforms and hydrologic fluxes. In doing this, Picea abies helps maintain environmental factors that favor the success of spruce relative to competing trees.

Here’s the way Pavel and I depicted it in a scientific article (Phillips and Samonil, 2021; available here):

Biogeomorphic effects of Picea abies limiting the development of fluvial dissection and channelized surface drainage (Fig. 12 from Phillips & Samonil, 2021).

The trees create hummocky topography in two ways. First, the root growth displaces the soil upward, and roots grow mainly laterally, above the water table. This creates pronounced basal mounds around each tree (or sites formerly occupied by trees), with intervening low spots or swales. The shallow-rooted spruce are also prone to uprooting, which creates pit-mound pairs. The pits are where substrate is ripped up by roots; the mounds form as the uprooted roots decay and the displaced soil falls to the ground. These processes create irregular microtopography in an area of thin soils (glacial and periglacial processes predominated before the Holocene). This leads to low connectivity for surface flow, as runoff from the local highs quickly finds its way into one of the pits or swales. And so also for subsurface flow, where potential pathways are disrupted. With limited connectivity there is little opportunity for flow convergence sufficient to incise channels. As a result, channelized surface flow is rare, and the drainage density is very low.

But there’s more! The shallow, laterally-oriented root architecture of P. abies helps direct infiltrated water and subsurface flow laterally rather than downward, and the roots do not penetrate as deeply into the parent material as trees with taproots or more vertically-oriented root architectures. This leads to limited thickening of regolith and soil. These factors (plus the ability of spruce litter to hold moisture near the surface) create an environment of poor soil drainage and wet surface layers. Of all the trees in that region, spruce is best adapted to those conditions.

Summary of how biogeomorphic feedbacks of Picea abies maintain favorable habitat for the species. Subsystem at left is the same as the figure above. (Fig. 13 from Phillips & Samonil, 2021).

Details and supporting evidence are available in our article.

Now take a careful look at Petr’s painting:

Biogeomorphological domination (Petr Mores).

You can see the hummocky topography, where neither surface nor subsurface runoff can flow very far before encountering an obstacle or a hole to go down. You also see the reasons for the topography—the basal mounding of the trees, and the uprooting of some trees. You see no surface channels, and the dense but shallow and disk-like root systems of the spruce. No channels are shown. Other cool details Petr was able to include are discussed in part 1 of this thread.  

One of the points I made in the earlier post was that many unmanaged forests are characterized not by the relatively open setting shown above but by a dense tangle of logs and limbs. Petr’s drawing below shows one of these:

Forest scene from an unmanaged forest in the Czech Republic (Petr Mores).

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Reference: Phillips, J.D., Šamonil, P. 2021. Biogeomorphological domination of forest landscapes: An example from the Šumava Mountains, Czech Republic. Geomorphology 383, 107698.   https://doi.org/10.1016/j.geomorph.2021.107698

Over the past decade(!) I have worked off and on with Czech colleagues on various aspects of the coevolution of soils, landforms, and ecosystems in forests, particularly unmanaged forests of central Europe.  In the course of working on one of those projects, dealing with biogeomorphological domination of hydrology, geomorphology, and vegetation in high elevations of the Sumava Mountains, we began to think, not for the first time, about different ways to tell the story. The conventional scientific article version is described, and is available, here.

I recalled meeting, and being impressed by, the work of an artist friend of my research colleague Pavel Šamonil--Petr Mores, based in Brno, Czech Republic (yes, I know, there’s a vowel shortage in Brno). Pavel connected me to Petr, and we began thinking and working on scientific storytelling through Petr’s medium, painting.  I have previously blogged about these conversations: Pictures of landscape evolution, Underground art.

Now we take a deeper dive into Petr’s most complex piece, shown below. The creative process is partly described in the earlier posts, but mainly it consisted of Petr’s multiple iterations of the illustration, followed by Petr’s scientific questions for Pavel and myself, and our comments and critique on the pictures. This is just a bumper-sticker version of how the collaboration worked; Petr spent a lot of time working on and thinking about not just the whole scene, but how to best depict specific aspects such as subsurface geology, soils, living and dead trees, etc. Luckily Mr. Mores enjoys nothing more than spending time in forests, and doing his art!

Biogeomorphological Domination by Petr Mores. I assigned the name; Petr may choose to give a better one.

Let’s break it down a bit. For starters, focus on the aboveground portion. Unlike many managed forests (tree farms being the most managed type), old growth and unmanaged forests have trees of a number different ages—both living and dead. These range from seedlings to mature trees to dead trees. The latter include some dying or recently deceased, with yellowish-brown needles still attached, and standing dead, with no needles. You’ll see downed trunks, both broken and uprooted. Some are still intact; some are highly decomposed, and serving as nurse logs for the seedlings, as is common in the Norway spruce (Picea abies) that dominate the study sites. One of the advantages of Petr’s depiction is that he was able to show all of these in a single scene, whereas with photographs it would be difficult, if even possible, to photograph trees in all of these states in a single image. After much discussion, we agreed that a surface area of about 30 by 30 m was necessary to provide enough room to show all we wanted to show, but with enough local detail to achieve our goals.

Now let’s go down to the ground surface, where the painting shows a number of the key effects of the Norway spruce on topography, soils, and hydrology. Some trees produce mounds at their base as the roots grow laterally near the surface and displace soil. Norway spruce is one of these (some other trees have fewer lateral roots and have little or no surface mounding). The painting shows not only mounds at tree bases, but some older mounds from past trees—the mounds do generally persist—and cutaway views showing the root mass at the base of the tree. Fallen logs and large lateral roots near the surface can also create more linear mounded features. This helps produce a hummocky topography. Another major effect is uprooting. Not only does this displace the underlying soil and rock pulled up with the rootwad, but as the rootwad eventually decays it leaves a pit-mound pair. The pit-mound microtopography, along with the hummocky topography, profoundly influences subsequent water flows, soil formation, and ecological processes. Since the roots often encircle stony glacial and periglacial debris, or penetrate bedrock where the latter is near the surface, uprooting also “mines” rock, deepening soil and bringing rock fragments to the surface.

Another advantage of painting vis-à-vis photography is the ability to show both above- and below-ground features simultaneously. The camera cannot see beneath the surface, and photographs of soil pits, outcrops, and exposures cannot show well both the exposed subsurface material and the surrounding landscape. Petr was already quite experienced in painting natural landscapes, but not so much on the subsurface. He visited a number of quarries and outcrops, and studied many of our photographs to get a feel for the rock and soil portion.

Some key things to note: The rock is jointed and fractured, as it nearly always is. These features are important for allowing water, roots and other biota to get into the rock, accelerating rock weathering. This is generally associated with positive feedbacks, where initially less resistant areas weather first, facilitating further weathering, and more resistant portions of the rock persist. This often—as in our study area—creates a spatially variable pattern of relatively deep pockets of soil and regolith, surface bedrock outcrops with little or no soil, and everything in between, overlying an irregular bedrock weathering front. Note also the decreasing degree of rock weathering and fracturing with depth. The soil is relatively thin in most places, with the dark, organic rich A horizon (topsoil) clearly indicated. The browns and yellows in the soil (note the contrast with the rock) are due to formation of iron oxides, which is commonly the case.

Not everything is shown, of course. Unlike a managed forest, where much of the biomass is removed by harvest and much of the remaining “slash” is burned, in an unmanaged forest everything dead falls to the ground and decomposes. There is often a great deal of litter, from freshly fallen to humus (the most advanced stage of plant litter decomposition), and including wood of all sizes (tiny twigs to trunks), leaves (spruce needles in this case), and seeds such as nuts or cones. The painting does show some dead trees on the ground, but after extensive experimentation we determined we couldn’t simultaneously show all the ground litter that would normally be there as well as the other features. However, while the painting is not necessarily typical in this regard, there are sites at any given time with less litter that look like the painting.

Note also that the painting is geographically specific. That is, it represents high-altitude spruce-dominated forests in the Sumava Mountains (which are along Czech Republic’s border with Germany and Austria). It would not necessarily apply to other sites with other trees, or a different environmental setting, though many of the specific phenomena shown are quite common.

The painting is also intended to convey a sense of movement and dynamism. Some of the latter is evident in rocks at various stages of weathering, trees of different ages, dead trees in different states of decay, and thin simple poorly developed along with thicker more highly developed soils.

The following annotated versions of the scene also show various mass and energy fluxes in the upward, downward, and lateral directions. Some processes (e.g., evaporation and transpiration) are invisible, but others are either clearly evident, or more subtly expressed.

More on this to follow . . . .

Catchy title, huh?

This is a story about scientific methodology and how experience, reasoning, and theory from quite different starting points (the consilience part) can lead to the same intellectual destination (equifinality). These starting points range from dialectical materialism, which is redolent of Marxism, to cybernetics, which smacks of computer science and robotics. 

The common destination is an approach to science—and I am focused on geosciences and ecosystem science—based firstly on recognition that our objects of study are interconnected systems of mutually adjusting components. This is straightforward to understand and explain. Certainly much has been, and continues to be, learned from reductionist science that seeks to isolate these interacting components.¹ But no ecologist, geographer, pedologist, geologist, etc. would argue that we can ultimately understand our objects of study without putting the pieces together; without at least considering contexts and interactions. 

Secondly, my approach (as in the approach I use & prefer; I am not claiming ownership or authorship!) is based not just on interactions but on constant coevolution and mutual adjustments.² I’ll use the term Earth surface systems (ESS), as I have before, as an umbrella term for biophysical landscapes, environmental systems, ecosystems, geomorphic and soil systems, etc. So, the idea is not just that a change or input to one part of the system triggers reactions in other parts, but that these reactions are ongoing, and repeatedly, if not constantly, reverberating through the system. 

Figure 1. Summary of my view of an integrated approach to landscape evolution.

I will tell you a bit about how I first got steered toward this worldview and methodology, and experiences and ideas that reinforced and refined it. I will also relate other journeys to the same general destination. 

That leads to a couple of key questions: Does it make a difference, once at the methodological destination, how you got there? Does consilience or convergence signify multiple lines of evidence that point to truth?

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1976. I show up in Blacksburg, VA, a sophomore transfer to Virginia Tech intending to major in forestry. After calc, physics, chemistry, and forest surveying, I had room for one more course, and I picked General Systems Ecology, which required only general biology, which I’d had, as a pre-req. 

The course was difficult, and much of what the prof, Dr. Robert Giles, said went over my head. But the parts I understood, and what I inferred about the rest, were like opening a door to a new way of understanding the world. The course applied hardcore von Bertalanffy general systems theory to ecosystem ecology, in the context of wildlife management (it was a fisheries & wildlife course). As a budding environmentalist and lifelong (well, at that point 19 years worth, anyway) Nature Boy, the holistic perspective suited me well. And the idea that one could take a broad, system-level, everything-is-connected viewpoint and still be rigorous and analytical (rather than the more intuitive and poetic approach I would have previously guessed would be necessary) was both revelatory and empowering. Giles and the textbook he used (K.E.F. Watt’s Principles of Environmental Science, 1973), painted a picture of complex, ever-changing environmental systems where changes could reverberate long and far past an initial modification or disturbance—but where rules do apply, and can be identified. The fact that rules can apply at a system level—as opposed to the literally or figuratively atomic level I was learning in my physics, chemistry, and biology classes—began to make the world seem much more interesting. 

By the time I graduated from Tech, I wanted to be an environmental journalist rather than a forester (can you believe I went in thinking foresters were the guys who loved trees, not the ones who cut ‘em down and ground ‘em up?). After working as a newspaper journalist for a bit, I decided to go the environmental science route and head to grad school. Now it is relatively straightforward to go into, say, a geology or soil science or biology program and work at the interface of different aspects of the environment. In 1980, not so much. I had stumbled across Richard Chorley and Barbara Kennedy’s (1971) Physical Geography: A Systems Approach, and found my way to the nearest geography program, at East Carolina University, as I still needed to keep my job to support myself. 

So I found myself in a field that, even 40+ years ago, was all about bio-geo-climate-hydro-soil (and human) interactions. And while not all geographers (then or now) were into systems theory, it was an accepted and familiar perspective. 

In my PhD studies at Rutgers my advisor Karl Nordstrom was a bit leery of systems theory in the fairly abstract and (as he would say) arm-waving approach I tried to employ then.  But he was not opposed to it on any basic principles, and the net result was that he obliged me to tie my radical techniques³ firmly to solid, empirical ground truth. That experience taught me the value—now I would say the necessity—of problematizing theory and methods from within the domain of interest (coastal geo-ecosystems at that point) rather than from the original domains of the techniques. It was a lesson I would relearn several times throughout my career, as geoscience colleagues were skeptical—if not downright aghast—at some of my theoretical notions unless I could link them firmly and clearly to real-world observations.

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As I collected estuarine salinity data for my M.S. thesis and vegetation, sediment, and other data for my PhD, I could not help but notice how variable some parameters were over small areas and short distances, with no discernible or measurable factors or controls to account for them. Often they appeared nearly random, or at least with random-like patterns superimposed on some very general broader-scale order. The general approach to such irregularity at the time—and such phenomena were certainly obvious to anyone who stepped into a soil pit or monitored more than a few vegetation plots—was to ignore/shrug it off, or focus on folding it into the broader general patterns as unexplained local aberrations, as in the “nugget effects” of geostatistics. 

Part of the New Jersey shore of Delaware Bay, my dissertation field site in 1983-4 (Google Earth^TM image).

That would have been fine with me if the world really was dominated by regular patterns, with variations linked to observable controls, blemished by occasional local deviations. But the regularity isn’t always dominant, and even where it is clearly evident, the local deviations are much more frequent than your occasional anomaly. I began searching for ways to understand and explain complex local spatial variability without resorting to a full case study of every single auger hole or section of outcrop or vegetation patch or bit of channel. 

At this stage I stumbled on Rudy Slingerland’s short 1981 article (in Geology), “Qualitative analysis of complex systems, with an example from river hydraulic geometry.” Yes. Here was a way to start getting at that spatial complexity, and though it took me a long time to get the math involved, the fact that it was clearly linked to general systems theory gave me an access point. Over time I discovered links to many other theoretical and methodological approaches, but at that point I was headed toward my integrated view of ESS evolution.

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So that’s how I got (t)here. But many other people have come to a similar place through quite different pathways, and, alas, not very many guided by me or by my writings. One route is cybernetics, defined by its pioneer Norbert Wiener in 1948 as the study of control and communication in the animal and the machine. Though closely related to systems theory, cybernetics has focused more on how systems function with respect to, as mentioned above, control and communication. There are traditions of cybernetics applications in ecology and geography, and to lesser extents in evolutionary biology, geology, and hydrology, that go back to the 1950s. 

Another route to thinking about nature in terms of ongoing reciprocal interactions is through models such as Lotka and Volterra’s predator-prey models from the early 20^th century. Ecological and population biology models with networks of mutual adjustments were in fact a key component of the development of complex systems theory in the 1980s. Complex adaptive systems (CAS) theories and methods, first developed in sociology, also lend themselves or lead to an approach based on evolving systems characterized by ongoing networks of interactions. CAS has found application in a wide variety of fields, including Earth and Environmental sciences. 

But what go me to thinking about this is the idea that my approach could have arisen from Engels’ (yes, that Engels) writings on the dialectics of nature in the late 19^th century. 

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Dialectical materialism and Frederick Engels are inextricably linked to Marxism. However, it still amazes me that so many do not understand that one can use dialectical research approaches entirely independently of Marxist politics and philosophy (and that many avowed Marxists have little or no interest in dialectics as a research tool). Dialectics or historical materialism doesn’t make you a Marxist—though even if it did it would not invalidate (or validate, for that matter) whatever you might discover using those methods. 

Dialectics is commonly defined as “the contradiction between two conflicting forces viewed as the determining factor in their continuing interaction.” By that definition, the study of ESS is dialectical. Much of what we understand about ESS is based on dialectical relationships at an absolutely fundamental level. A few examples:

I have previously blogged about the possibilities of taking a fully dialectical approach to geomorphology.

Engels and subsequent scientific dialecticians, like systems theorists, are interested in alternatives to Cartesian reductionism, which is based on the notion that any system can be broken down into homogeneous parts. The parts are ontologically prior to the whole, and have intrinsic properties that are contributed to the whole. Reductionism also assumes that causes and effects are separate and that subjects can readily be distinguished from objects, and effects from causes. 

In contrast, Richard Levins and Richard Lewontin (in their 1985 book The Dialectical Biologist, and drawing directly from Engels), identify five key principles of dialectical materialism (italics are mine):

(1) The whole is a relation of heterogeneous parts, which (2) have no prior or independent existence as parts. (3) Wholes and parts interpenetrate each other, as subjects/objects and causes/effects may be interchangeable. (4) Change is characteristic of all systems and their aspects, and (5) contradictions are ubiquitous in nature. 

Thinking about this in terms of my approach to ESS made me think I must be a dialectical materialist!

My home boy, Frederick Engels.

And maybe I am. If I object to being called one, it is only because I am uncomfortable with labeling myself with –isms of any kind, not because I can’t see the obvious connections to my work, or due to its association with Marxism. 

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But am I really? If I independently develop a set of beliefs and a moral code that is consistent with that of, say, the Presbyterian Church, does that make me a Presbyterian?

As Earth and environmental sciences evolved, a great many scientists have come to both preach and practice an approach based on interconnected, evolving systems with mutual adjustments and reciprocal causality among their components, including (inevitably) a number of dialectical contradictions. In many cases, probably most, these arose with no direct connection with dialectical materialism, general or complex systems theory, cybernetics, complex adaptive systems, or other prescriptive or proscriptive philosophies or conceptual frameworks. Rather, they seem to have emerged organically due to the pragmatism (for those who insist on –isms!) that dominates our science. That is, this approach works because it accurately reflects our observations and provides tools to make progress toward our research goals. 

This is reflected in, among many other things, the recent and recent-ish emergence of hybrid subdisciplines. For the most part, studies of geo-eco-hydro-pedo interactions were mainly one-way with respect to causality, rather than reciprocal interactions. A growing recognition that biota, landforms, soils, and hydrology (and climate) are best understood as responding and evolving together, along with increasing attention to reciprocity, inspired the birth of several focusing directly on these reciprocal interactions. 

Biogeochemistry is the oldest of these, dating at least to Vernadsky in the 1920s, focusing on the cycles of elements such as carbon, oxygen, nitrogen, and phosphorus, which involves both biochemical and geochemical processes (as well as geophysical and biological transport processes) and interactions among the atmosphere, biosphere, and lithosphere. There also exists a tradition of geoecology, dealing mainly with intertwined geomorphological and ecological processes. These have been joined more recently by ecohydrology, which emphasizes interactions and feedbacks between ecological systems and the hydrological cycle. Biogeomorphology (or ecogeomorphology) is concerned with the influence of landforms and surface processes on the distribution and development and functioning of organisms and ecological systems, and with the simultaneous influences of biota and ecological dynamics on Earth surface processes and the development of landforms. Hydropedology was proposed to link traditional pedology with soil physics and hydrology, while geobiology explores the relationship between life and the Earth's physical and chemical environment.  

The terms Earth system, climate, ecosystem, and critical zone science have come into wide use in recent decades.Earth system science emphasizes the dense, reciprocal interconnections of the atmo-, hydro-, litho-, and biospheres, especially at very broad--including global—spatial scales and at time scales from fluid dynamics to planetary evolution. As concerns with impacts of contemporary climate change accelerated in the late 20^th century, informed by studies of climate change and evolution in Earth history, some scientists sought to expand the perception of that research area to encompass but also transcend climatology, paleoclimatology, and atmospheric sciences. Thus, climate science emerged to also include the study of climate impacts on, and feedbacks with, human and other biophysical systems. The term ecosystem science emphasizes that the field transcends ecology, with strong links to landscape ecology, global ecology, biogeochemistry, aquatic ecology, soil science, hydrology, ecological economics and conservation biology. Critical zone science is an integrated approach to the study of rock, regolith, soil, water, biota, and atmosphere interactions near Earth's surface, with the critical zone defined as the planet’s permeable near-surface layer from groundwater to treetops 

Taken together, the growth of the terminology and associated concepts and subdisciplines mentioned above testifies to recognition that no aspect of Earth's system(s) can be fully understood in isolation from the others, and that ESS are characterized by constant internal and external feedbacks and reciprocal interactions. 

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Precursors of many of these subdisciplines and their underlying ideas do include a disproportionately large number of Russian and Soviet scientists, some of whom were avowedly Marxist, and all of whom had certainly been exposed to, if not indoctrinated in, dialectical materialism—In addition to Vladimir Vernadsky, this list includes Petr Kropootkin, V.V. Dokuchaev, Mikhail Budyko, RV. Rizpolozhensky, and V.A. Kostitzin. Cold war politics undoubtedly impeded the diffusion of these ideas into western science. 

But while much of the thinking in the subdisciplines mentioned above could have arisen from a dialectical perspective, there is not much evidence that any of it did, except perhaps indirectly through the “Russian school” scientists above, and others like them—and in fact the Russians are in general underappreciated and under-acknowledged. This suggests that, at least in post Cold War times, we got there mainly by other routes. 

Thus, if I want to try to convince someone of the utility of the integrated approach to landscape evolution summarized in Figure 1, I can do it with no mention of dialectics (as is in fact the case in a recent book²). Contrarily, I could also use my approach to argue that I am a dialectical materialist. Richard Levins, the openly Marxist co-author of The Dialectical Biologist, is also the co-author (with Charles Puccia) of Qualtitative Analysis of Complex Systems (1985), which became my methodological handbook back in the day. There is no trace of his politics or philosophical learnings in the latter book, and “dialectics” does not even appear in its index. 

The question to me at this point is: What difference does it make? Or even, who cares? This is not a challenge to any particular –ism. Nor is it a rhetorical question: I truly wonder what difference it makes. 

Let’s go ahead and stipulate that anyone’s experiences, education, inspirations, and social, political, and cultural contexts has some influence on what they do and how they do it, be they a pedologist, a trombonist, a truck driver, or a farmer.  Beyond that, the differences in how they study soils, play the ‘bone, drive a truck, or grow crops is important. But does it matter to their harvests, travels, music, or study results how or why they came to farm, drive, play music or do soil research they way they do? 

The noted dialectical pedologist Fred Wesley. Just kidding—Mr. Wesley is a legendary soul, funk, and jazz trombonist. 

I don’t know. But to those who are inclined to try to understand our world from a similar perspective to mine, whether you got here via Marxism, Methodism, mathematical modeling, metaphysics, or marine biology—welcome! Let’s get at it.

Footnotes

¹Reductionist science will always be necessary to understand how the components of systems interact with each other. 

²This approach is laid out in edge-of-your-seat thrilling detail in Landscape Evolution.

³These would seem routine, now. But in the early 1980s I had to write my own FORTRAN programs to do geostatistics and compute fractal dimensions—and submit decks of punch cards to the computing center to run the programs. So only a few people were fooling with these relatively new techniques then. 

Posted 13 January 2022

The parable of the boiling frog holds that if you drop the frog into boiling water it will do everything possible to get out immediately and avoid being cooked alive. On the other hand, if you gently place the frog into a pot with water at room temperature it will stay calm. Then, as you very gradually turn up the heat, the amphibian will get ever groggier until the water reaches the boiling point and kills it. The frog parable/metaphor has been employed many times in many ways to reflect human tendencies to be able to accept and adapt to minor incremental changes (or to not even notice them) until finally some threshold is reached whereby we realize things have, not to put to fine a point on it, gone to shit. The frog is boiled.

In terms of actual biology and frog behavior there is no evidence that the parable is accurate. But as a metaphor for out perceptions, it is often right on target.

Recently, in dealing with an elderly relative who has become virtually helpless, I thought that I would never let myself get that way, and told my wife to take action if I did. But it is not like you simply wake up one morning and your memory is gone, your hearing is shot, you can’t move around without a wheelchair or walker, and other things that I won’t mention have set in. It happens little by little, and maybe you don’t even notice it on a day-to-day basis, and if you do, you just deal with it. And then, over the course of just a few years, it is too late. You no longer have the wherewithal to punch your own ticket, and you can’t really ask a loved one to do it for you, especially when they can’t even be sure you’re in your right mind when you ask.

The frog parable is apt in many cases of adapting or surrendering to human impacts on the environment. Take urban sprawl—every year the air gets just a bit dirtier, the traffic gets a little worse, the infrastructure is strained a bit more, and then you have southern California. Or Atlanta. Or Houston. Or Washington. And so on, ad infinitem.

We need to keep the parable in mind as we study, plan for, and actually adapt to climate change. It is happening now, has been going on for a while, and will continue. Some changes will be incremental and more-or-less gradual—ocean temperatures increase, crop yields rise or fall, biogeographic ranges expand or contract, sea-level creeps up, etc. But sooner or later the metaphorical boiling point is reached. The ocean doesn’t just get warmer, but tips into a new normal with respect to tropical cyclone regimes or global thermohaline circulation. Crop yields don’t just change, but whole agricultural systems become untenable (or newly tenable). Species don’t just spread or contract their ranges, but invade vast new territories or decline to local extinctions. Water levels don’t just creep up, but trigger geomorphological and ecological regime shifts.

These transformational boiling points do not occur just in response to major global environmental changes or to human impacts on the environment. They are how nature works. In my recent Landscape Evolution book I put this in terms of TREE: Transformational, Reciprocal, Emergent Evolution. The transformational term reflects the fact that Earth systems change over time by transforming, by changing states. Geomorphological, pedological, ecological, and hydrological systems are all governed by thresholds. In many cases these thresholds correspond to tipping points, regime shifts, and wholesale transformations—sea ice to open water; savannah to desert; freshwater to saltwater; eutrophic to oligotrophic; farmlands to badlands, etc., etc. As it gets hotter, colder, wetter, drier, stormier, and so on sooner or later biological, ecological, or physical thresholds will be crossed. Transformations will occur.

If you doubt that major transformations can take place under our noses in a couple of generations, or a single lifetime, I suggest Jack Davis’ book The Gulf, about the Gulf of Mexico and its coastal zones. Or for a similar example closer to (my) home, Glenn Lawson’s Troubled Waters (Hadnot Creek Books, 1990). It doesn’t take a strip mine or a nuclear meltdown or an armada of excavators and paving machines to transform a system.

So what does this mean for Homo sapiens? First, we need to recognize that transformations will happen (and are happening: for many examples, see the regime shifts database). Second, we need to better understand when and how these state changes happen, so that we can anticipate them. Many will be unavoidable, but some may be so damaging that they need to be mitigated (and some we may want to embrace or encourage). Third, we need to think in terms of adaptation and fostering our own transformations, as opposed to just attempting resist climate-fueled changes or try to put things back as they were. This was the theme of a previous post.

In 2018 Melissa Parsons and Martin Thoms (quoting various academic sources), noted that resilience has, on one hand, been described as a powerful lens through which to view major issues, a systems approach to understanding change, and an organizing concept for radical change. On the other hand, resilience has been characterized as having the potential to become a vacuous buzzword, a word of the year, and an academic bandwagon (Parsons and Thoms, 2018: 242). 

I will not parse the various meanings or explore the dimensions of resilience here; it is clear by now that due to the various meanings attached to the term, one should always define it if a specific version of resilience is intended, or perhaps choose a different, less contested term. Discussions of resilience, by virtually any definition, are critical now in the context of planning for and responding to climate change. Significant changes are happening now and will continue (and likely accelerate) in the future, and Earth systems (including humans) will have no choice but to respond one way or another. 

The purpose of this post is to propose that with respect to semi-natural, biophysical systems such as ecosystems and landscapes, the most promising approach to preparing for and responding to climate change is based on adaptation and transformability. These concepts, as I define them below, are consistent with many strains of resilience.

Biological adaptation in ecological and evolutionary contexts is often defined as the adaptation of living things to environmental factors for the ultimate purpose of survival, reproduction, and an optimal level of functioning. To avoid defining something in its own terms, substitute “adjustment” for adaptation, and to broaden the definition, substitute “environmental systems” for living things—that is what I mean by adaptation in this paper. Transformability is the capacity to create a new system when changed conditions make the existing conditions untenable (Thoms et al., 2018). 

Though I prefer separating the concepts of resistance and resilience, they are often combined or conflated. Thus, resilience may be seen in some instances as capacity of a system to defend itself against or absorb changes. Resilience is also often defined in terms of recovery; or the ability of a system to return to or toward in previous state following a change or disturbance. 

There is nothing wrong with either of these notions, except that in the context of climate change they may be unfeasible, impossible, or counterproductive. Rather than preventing change by increasing resistance or restoring previous conditions, the adaptation/transformation approach is based on acceptance of change as inevitable. To use a boxing metaphor, when getting punched is inevitable, adaptation is akin to rolling with the punch rather than hoping to take a punch and remain standing (resistance) or get up off the canvas after getting knocked down (recovery).

Take, for example, the issue of water resource allocation in dryland areas such as much of the American west, the Middle East, Northern Africa, and Australia. Where climate change reduces water available (by reducing precipitation, increasing evapotranspiration, limiting snowpack storage, shrinking glaciers, or some combination of these) a resilience approach would typically focus on increasing water storage capabilities, a search for new water sources or supplies, and development of programs for drought relief and recovery. An adaptive approach, by contrast, would prioritize transformations of, e.g., agriculture, industry, and households to less water-intensive and dependent crops, products, production processes, and cultural practices. 

Drought in New South Wales, Australia (https://utilitymagazine.com.au).

This example also serves to illustrate the similarities and overlaps of adaptation and transformation thinking vs. (traditional) resilience thinking. Both strategies, for instance, would embrace improved water use efficiency and more aggressive conservation. Transformations of agriculture and horticulture would involve use of plants that are more drought resistant and recoverable. 

*   *   *   *   *

Some things we need to get straight and keep in mind. These are not revelations, nor are they assertions. These are reminders of important facts that we need to bear in mind, whether resisting, recovering, adapting, or transforming.

•Climate change such as global warming is real. It has already happened, it is happening now, and will continue to happen. 

•Climate change is unstoppable. Yes, we can slow it down, but for at least several generations climate change due to human agency will happen no matter what we do going forward.

•Climate change is, and will be, unsteady and erratic. The long-term trends are entrenched for a while, but the inevitable hourly to decadal changes, episodes and cycles will be overprinted on top of that. Though on average it will get hotter, for instance, there will still be relatively warmer and cooler years. Some areas will get progressively drier, but there will still be wetter and drier spells. 

•”New normals” are here. What used to be exceptional heat waves will become commonplace. Bad fire seasons become typical fire seasons. Tropical cyclones get more frequent, powerful, wetter, and slower moving. And so on. Concepts based on assumptions of statistical stationarity—e.g., the hundred-year rainfall event or the 500-year flood are useful benchmark conditions but are becoming less useful—even useless—for planning purposes. 

•In the middle of an episode or event, it is difficult (and sometimes impossible) to determine whether it is an isolated, one-off event, part of a trend, or something that would have happened without human-influenced climate change. Was Barry Bonds’ 71^st home run of 2001 due to steroids? Would he have hit it anyway (he did hit some homers before he got on performance-enhancing drugs)? Or was it because Chan Ho Park grooved a pitch that most major leaguers would have knocked out of the park? We can say with absolute confidence that Bonds would not have hit 95(!) homers that year without steroids (about 1.5 times the pre-steroid-era record), but we cannot say to what extent any individual homer is attributable to steroids. 

•Unprecedented weather and climate events will occur. The historical record is extremely useful, but we cannot use it to fully prepare for the future. 

*  *  *  *  *  *

Lessons from nature:

•Adaptation by selection: Biological adaptation operates by selection, whether Darwinian natural selection in evolution or ecological filtering. Adaptive selection also occurs in other environmental phenomena, including abiotic processes. This probabilistic selection serves to form, enhance, and preserve more efficient and resistance processes, structures, relationships, and networks. We should thus learn from selection processes in (non-human) nature what “works” in adapting to climate change and should formulate our proactive adaptation with selection in mind. We should also bear in mind that selection is negative as well as positive (filtering out what doesn’t work as well as reinforcing what does) and imperfect. Thus, we should be flexible and adaptive in our adaptations. Can natural ecosystems provide lessons for managing and planning urban ecosystems and industrial ecologies?  Can unaided (by humans) responses to disturbance inform human efforts at restoration and rehabilitation? This principle also implies that failures in human adaptations may be due to inconsistency with the applicable selection principles, so that it is often not suitable to try the same approaches repeatedly or consistently.  

•Hydrological systems develop (driven by efficiency selection) and persist when they develop “store-and-pour” capabilities. This enables them to temporarily store and slowly release excess water during high-input periods, to efficiently convey flow during normal periods, and to preserve some water resources during dry spells. Any design or management of hydrological systems (and ecosystems) should seek to preserve or mimic this property. For example, in some cases, river corridors along low-gradient coastal plain rivers have been evolving under a regime of rising sea-level, and have developed a store-and-pour morphology well-adapted to handle both storm surge flooding from downstream and river floods from upstream, often simultaneously. This indicates an adaptive strategy of maintaining these channel-wetland systems and prioritizing them for preservation. Studies have shown that farming strategies geared toward minimizing disruption to the dual-porosity properties of soils improves soil health and crop yields. Percolation and constructal theory, among others, have shown how store-and-pour systems can increase the efficiency of engineered flow patterns for many kinds of fluids. 

Part of the fluvial-estuarine transition zone of the Neuse River, N.C. This area has developed store-and-pour morphology that is adapted to flooding from both downstream storm surge and upstream flooding. Thus, when Hurricane Florence in 2018 caused the highest storm surges ever recorded and record river floods, the effects were absorbed with limited geomorphological, hydrological, or ecological change (Phillips, 2022). 

•Landscapes (including geomorphic and soil landscapes, ecosystems, and hydrological systems) are characterized by TREE: Transformative Reciprocal Emergent Evolution. Transformative means that development over time often involves state changes and transformations to fundamentally different conditions. Thus, the transformations implied or prescribed in the framework are a natural, inherent way to respond to climate changes, and landscape transformations provide useful benchmarks and analogs for human responses. Transformation is common and natural. The state of an environmental system (human influenced or otherwise) is essentially a snapshot of an episode in a history of constant change. Under climate change we cannot expect environmental or economic systems to remain unchanged or only somewhat modified. Many are being, and will be, transformed. This will call for hard decisions in determining whether it is feasible, or even possible, to maintain or restore affected systems. We will have to recognize that maintaining or restoring a transforming system (e.g., a desired ecological community, an agricultural production system, a transportation network) will be difficult, expensive, and unending. We also need to recognize that in many cases transformation in human activities will be necessary—e.g., phasing out of fossil fuels or switching to electric vehicles. We should also be alert to opportunities to steer transitions, as there often exist multiple possibilities for landscape transitions.        

•The reciprocal in TREE refers to the highly interrelated character of environmental systems, where everything is connected to everything else. You can fertilize the ocean to increase carbon storage, for instance, but you cannot expect to do so without complex ripple effects (some of which might be deleterious) throughout marine and coastal ecosystems. 

You cannot change (only) part of a system. There will be chain reactions and reverberations throughout the system, many of which are difficult or impossible to foresee. In the case of mega- or geoengineering, this may suggest foregoing these options, or keeping them as a last resort, as the side-effects and collateral damages may be too great a risk. In the case of more readily managed phenomena, such as modifications of market systems and trade networks, we should be flexible and prepared to respond quickly to negative side-effects. 

•The emergent in TREE refers to the fact that independent of humans, Earth systems cannot consciously strive toward any goals or stay on any single developmental trajectory. Their behavior emerges from fundamental processes and relationships within the system. For example, no laws or principles dictate that hydrological flow systems develop any particular structure or pattern. Yet, many surface, soil, and groundwater flow systems develop a “store and pour” morphology through emergent phenomena First, concentrated flows form due to principles of gradient and resistance selection. Second, positive feedback reinforces the concentrated preferential flow paths and their relationship to potential moisture storage zones. Third, intersecting flow paths form networks. Fourth, the expansion of concentrated flow paths and networks is limited by thresholds of flow needed for channel, macropore, or conduit growth and maintenance. This results in a “store and pour” flow system that can retain water during dry periods and transport it efficiently during wet periods. These survive provided they develop “spillway” and/or secondary storage mechanisms to accommodate excess water inputs. 

Understanding the principles and processes of emergence can guide our assessments of environmental change, and perhaps provide openings for opportunistic interventions. 

•The evolution in TREE reminds us that Earth systems indeed evolve. We cannot create, restore, or otherwise influence a system and expect it to remain in that state indefinitely. It will change, along the lines of TREE. Conversely, this reminds us that if we want to maintain Earth systems in a particular state it will require ongoing management or at least occasional interventions by humans. 

•Dynamical instability happens. Small changes and disturbances may have effects that grow much larger than the disturbance and lasts far longer. As large events may sometimes have disproportionately small impacts, this means that effects are often not proportional to the magnitude of changes or events. It is therefore critical to think in terms of amplifiers and filters—the former, such as ice-albedo feedbacks, tend to amplify effects of climate change. The latter resist or damp climate impacts—for example, bedrock-controlled stream channels are less likely to show strong morphological responses due to their high resistance to erosion and channel migration. 

* * * * *

As an overall guiding philosophy for adapting to climate change, I turn to actor, director, martial artist and philosopher Bruce Lee. We cannot ignore climate change, nor wish it away. We cannot stop it entirely, and we cannot keep everything the way it is. So the operable approach is to be like water. Lee expressed this idea on numerous occasions, but the best known is from a 1971 appearance on the Pierre Berton show:

“Empty your mind.

Be formless, shapeless, like water.

You put water into a cup, it becomes the cup.

You put water into a bottle, it becomes the bottle.

You put it into a teapot, it becomes the teapot.

Now water can flow or it can crash.

Be water, my friend."

References

Parsons, M., Thoms, M.C. 2018. From academic to applied: Operationalising resilience in river systems. Geomorphology 305, 242-251. 

Phillips, J.D. 2022. Geomorphic impacts of Hurricane Florence on the lower Neuse River: Portents and particulars. Geomorphology 397, 108026.

Thoms, M.C., Piégay, H., Parsons, M. 2018. What do you mean, ‘resilient geomorphic systems’? Geomorphology 305, 8-19. 

Questions or comments: jdp@uky.edu

Posted 3 January 2022

Just published, in Geomorphology (2022, v. 397, 108026): Impacts of Hurricane Florence on the lower Neuse River: Portents and Particulars. Beyond documenting geomorphic impacts in three specific settings in, essentially, my current backyard, one of the main goals was to test the extent to which geomorphic impacts were attributable to the “new normal” nature of the storm, as opposed to tropical cyclones in general (portents); and to specific characteristics of both the lower Neuse region and the synoptics of Florence in the Carolinas (particulars). The “new normal” refers to the tendency here in the warmed-up and warming-up Anthropocene for more and larger tropical cyclones, and for these storms to hold and deliver more moisture, to move more slowly, and to expand in area (the whys of this are summarized in the article). As you can see from the abstract below, some aspects of Florence’s impacts are portents, while others are linked to the particulars of the place and the storm.

Another key takeaway from this work was that in the lower Neuse River fluvial-estuarine transition zone, there were minimal geomorphic impacts, though that stretch of the river corridor was battered by massive floods from upstream and record high storm surges from downstream. The reason? The corridor in this stretch is a complex of active channels, backflooded and high-flow channels, floodplain depressions, and wetlands that is pretty much perfectly suited to handle all that water, having evolved under the influence of Holocene sea-level rise. Wetlands protection programs have minimized disturbances in this area, thus maintaining its ability to absorb Florentine deluges.

I am doing some further research on the unique characteristics of the fluvial-estuarine transition zone (compared to the purely fluvial reaches upstream and the upper estuary downstream) and may publish something on that eventually (or may not, as my first attempt was pretty roughly treated by referees!). 

A giant snake in the lower Neuse River! Actually, it's the floating roots of an aquatic arrowhead plant (genus Sagitarria).

The article is attached.

Posted 11 November 2021

I’ve long been interested in plant roots in the context of their effects on geomorphology and soils, which are many (see the reference below, for starters). Having my antennae up for root research beyond the realm of botany and plant physiology, I came across a very interesting new article by Fredrik Sønderholm and Christian Bjerrum: Minimum levels of atmospheric oxygen from fossil tree roots imply new plant−oxygen feedback, in Geobiology (2021).  The abstract is below: 

They define root intensity as respiration per square meter of surface area, which is closely related to rooting depth. Previous work overlooked influences of atmospheric oxygen content on root intensity (as opposed to other aspects of vegetation), and of root intensity (essentially, belowground respiration) on terrestrial net primary productivity (NPP). By including root intensity, they identified two new feedback loops in the coupling of Earth’s surface, biosphere and atmosphere. First, root intensity positively influences NPP, which stimulates organic carbon burial, which encourages pO₂ (atmospheric oxygen concentration), which positively affects root intensity. The second has root intensity promoting NPP, which increases weathering, which stimulates organic C burial, and back to pO₂. This offsets the direct negative effect of weathering on pO₂, which uses O₂ in weathering processes such as oxidation. A key figure from their paper is below:

One of the key questions in the coevolution of Earth’s atmosphere and biosphere is how the oxygen content of the atmosphere has risen from nearly zero as the biosphere evolved, but been kept within a fairly narrow range for a long span of Earth history now. It seems that roots are a key part of the answer!

______________________________________

Pawlik, L., Phillips, J.D., Šamonil, P., 2016. Roots, rock, and regolith: biomechanical and biochemical weathering by trees and its impact on hillslopes - A critical literature review. Earth-Science Reviews 159: 142-159. (Attached)

Posted 11 November 2021

Questions or comments?  jdp@uky.edu

When I was an undergraduate student at Virginia Tech from 1976-79, in several environmental science, geography, and ecology classes we were taught about global warming and climate change due to human activities such as burning fossil fuels and deforestation. The physics behind warming due to increasing atmospheric concentrations of carbon dioxide, methane, and other greenhouse gases had been well known for nearly a century by that time, and the fact that carbon dioxide concentrations in the atmosphere were increasing was also firmly established. Empirical evidence suggesting that human-caused climate change was already occurring was beginning to accumulate. 

These were undergraduate courses, not specialized upper level or graduate courses. It takes (at least) a few years for cutting-edge science to make its way into undergraduate textbooks and lecture notes, so it is safe to say that climate change due to humans was common scientific knowledge 50 years ago. The Carter administration sponsored a study of potential impacts of global warming in the 1970s. This is not to say that all was proven by the 1970s. But the warnings were there, based on solid science, and the overwhelming weight of evidence ever since has supported the idea, now fact, that we are changing Earth’s climate in ways that are often problematic for humans, other species, and the planet in general. By 1981 I was involved in teaching this stuff myself as a teaching assistant in freshman-level physical geography. 

Now, the fact of global warming and climate change is undeniable. I guess there are a few holdout deniers  (as there are still a few who maintain Earth is flat, evolution didn’t happen, moon landings were staged in a desert somewhere, and Biden didn’t win the 2020 U.S. presidential election). But even the utility companies who burn fossil fuels and the automobile manufacturers who make fossil fuel burners are adjusting to climate change—late to the game, of course (hopefully not too late) and not always for the most noble of reasons—but 50 years on, they know they can’t avoid it and want to keep making money, if nothing else. We’ll know the corner has been completely turned when the right wing press begins to blame ever-higher sea surface temperatures on Joe Biden, Nancy Pelosi, and Barack Obama. 

All of the following, and more, in the news just within the past couple of days: Droughts and wildfires in the western U.S. More and stronger tropical cyclones. More frequent and intense floods and heat waves. Accelerated sea-level rise. Climate-driven refugees. Increased coastal flooding. Power outages linked to climate and climate change. Military and security risks due to climate change. Loss of polar ice. Conflicts over water resources. Climate impacts on agriculture. 

Every one of these, and more, predicted and warned of decades ago. 

Yes, the details were not known. Yes, there was some uncertainty at the time the predictions were made. But though the exact timing, severity, and nature of these climate impacts cannot be known until they actually occur, the basic fact that these things are happening is no surprise at all to anyone who’s been paying attention for the past 50 years. 

So, is there a point to all this beyond “told you so?” 

If Earth, environmental, climate, and ecological scientists have been right all along, maybe we should start paying attention!

We told you so, and are still telling you so. We/they will not be right on all points, all the time, and uncertainty will never be completely banished (“prediction is difficult, especially the future,” as Yogi Berra famously said). As my professor in one of those long-ago Virginia Tech classes (Robert Giles) said, “When the house is on fire, there is no time to calculate the BTU’s of heat energy being released. There might be time to get a bucket.”

Posted 25 October 2021

Comments or questions: jdp@uky.edu

Vernadsky (1926) developed the concept of the biosphere as a planetary membrane that captures, stores, and transforms solar energy. The proportion of solar energy captured by the biosphere is small compared to that represented by climate processes, but large compared to other energy sources for landscape processes A tiny fraction of net primary productivity doing pedologic and geomorphic work (e.g., bioturbation, bioweathering, bioerosion, organic matter formation) is (as a global average) a greater energy input for landscape evolution than geophysical processes (Phillips, 2009a).

The soil and the biosphere have been characterized as an “excited membrane” or skin at the planetary surface stimulated by solar energy (Vernadsky, 1926; Nikiforoff, 1959). Can other aspects of landscapes—particularly landforms and topography—be characterized as an “excited membrane?”

Since Vernadsky (1926), many others have noted that Earth’s atmosphere is in chemical disequilibrium. Its composition is maintained by photosynthesis, respiration, and other biospheric processes. Organisms are not a necessary condition for an atmosphere to exist, or for most of the atmospheric constituents of Earth’s atmosphere to exist. However, the current general nonequilibrium chemical composition, which has remained in approximate steady-state for >2 Ga, is inseparably connected to the evolution of, and maintenance by, the biosphere. But while Earth’s atmosphere contains the signature of a biosphere, it cannot be said to represent any particular taxa.

Present composition of Earth’s atmosphere, which has been pretty consistent for the past 2 billion years.

Biotic influences on surface processes, landforms, and soils are pervasive, and tightly-coupled reciprocal interactions are reflected in plant-soil interactions, biogeomorphology, ecosystem engineering, and niche construction. At least some soils and landforms can be considered extended (composite) phenotypes (Phillips, 2009b; 2016). Similar to the atmosphere, Earth would have landforms and regolith in the absence of a biosphere (and did before the appearance of life). Some soil and landform elements that would exist on an abiotic surface are present. However, contemporary soils, landforms and landscapes in their current state would not exist without biota.

Section of the meandering Sabine River on the Louisiana/Texas border. Landforms such as this, both in particular and in general, have most emphatically not been consistent for the past 2 billion years!

However, even as species, communities, and ecosystems have been in long-term evolutionary flux, the atmosphere has been maintained in an approximate steady-state. This is clearly not the case for soils, landforms, and topography on geologic time scales. Global revolutions since the Archean have profoundly and irreversibly changed the biosphere, pedosphere,and toposphere, while modifications of atmospheric composition, and of the general global hydrosphere, have been moderated and have not been irreversible (Lenton and Watson, 2011).

In the atmosphere and hydrosphere, biotic changes are rapidly propagated throughout due to their global interconnectivity, at velocities of fluid flows measured in m sec^-1. Soils and landforms, by comparison, are interconnected at more restricted spatial scales—subcontinental at the largest, and not infrequently over areas on the order of 100 m² or less. Propagation of changes sometimes occurs at fluid velocities, but other processes (e.g., weathering and denudation) have rates often measured in units of m yr^-1 to m ma^-1. Soils and landforms therefore have much longer response and relaxation times to biologically driven change than the atmosphere-ocean system, and impacts are local and regional rather than global. One implication is that landforms and soils have a much richer “memory” of biosphere change (independently of whatever fossils they may contain) than the other spheres.

Phillips (2016) speculated that the toposphere and pedospere locally absorb most of the environmental effects of biota, thereby buffering the atmosphere, hydrosphere, and lithosphere from major changes. There are examples of pedological and geomorphological change producing negative feedbacks to mitigate changes in composition of the atmosphere/hydrosphere. Biologically driven shifts in atmospheric carbon dioxide concentrations result in climate change, which in turn accelerates or decelerates silicate weathering rates, either absorbing or releasing atmospheric CO₂ to offset the biotically induced changes (e.g., Berner, 1992; Kump et al., 2000; Malkowski and Racki, 2009).

This raises some interesting questions with respect to Earth system evolution. The bio, litho-, atmo-, hydro-, topo-, and pedospheres coevolve at the global scale. Major biotic events have driven revolutions in the other spheres (Lenton and Watson, 2011), but the atmosphere and the global hydrological system seem to have been relatively steady-state at the global scale. The toposphere and pedosphere have not, and display substantially more spatial variability in responses than oceanic or atmospheric composition. This suggests that perhaps landforms and soils provide the major mechanisms or degrees of freedom by which Earth responds to biological evolution, at least within the context of the permanently oxygenated atmosphere and ocean that have existed for the past 2.4 Ga. There is some evidence to support this with respect to the carbon cycle and feedbacks among ecological processes, atmospheric and ocean chemistry, biotically-enhanced weathering, and soil and sedimentary carbon storage or release (Huggett, 1991; 1995; Lenton and Watson, 2011).  Landforms and soils may thus be the “voice” of the biosphere as it authors planetary change, even if or when clear biotic signatures are lacking.

References

Berner RA. 1992. Weathering, plants, and the long term carbon cycle. Geochimica et Cosmochimica Acta 56: 3225-3231.

Huggett RJ. 1991. Climate, Earth Processes, and Earth History. Berlin: Springer.

Huggett RJ. 1995. Geoecology—An Evolutionary Approach. London: Routledge.

Kump LR, Brantley SL, Arthur MA. 2000. Chemical weathering, atmospheric CO₂ and climate. Annual Review of Earth and Planetary Sciences 28: 611-667.

Lenton T, Watson A. 2011.  Revolutions That Made the Earth.  Oxford University Press.

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