Voices of Climate Change

Extreme environments are the outliers through which the full breadth of Earths dynamic phenomena can be observed. The response of fragile arid systems to a rapidly evolving climate is of particular interest to scientific communities aiming to understand an uncertain future. Two such projects, in Antarctica and in the New Mexico desert, have spawned art-science collaborations demonstrating how an interdisciplinary approach to sound and seismic waves can bridge the gap between the arts and environmental sciences, envisioning a practice where environmental concerns meet, relate, and resonate.

Sound is defined as a vibration that typically propagates as an audible wave of pressure, through a transmission medium such as a gas, liquid or solid. Sounds, or acoustic waves, are characterized by their frequency (Hz), amplitude (decibel), speed, and direction, and when propagating in solids they are referred to as seismic waves [1]. While humans can perceive an acoustic bandwidth of roughly 20–20,000 Hz, a whole range of sounds are emitted by our environment (and by the Earth itself) that remain inaudible to our unaided hearing. In the same way that blowing wind can affect the propagation of sound waves, dynamic alterations in the Earth can influence seismic wave characteristics, making them invaluable tools for probing and monitoring subtle Earth structures. Thus seismic surveys are at the forefront of studying the growing effects of climate impacts on Earth structures, from polar ice mass evolution to subtle soil alterations in arid climes (or, not so subtle, in the case of the Dust Bowl calamity in the 1930s, for instance), and have provided increasingly alarming views of a world under severe strain. However, as is often the case with specialized disciplines, the results are both inaccessible to a broad audience and are themselves limited by the scientific bubble (i.e., the tendency of scientists to fit their interests and interpretations to the limits of their tools). Although it is described mathematically as a propagating wave, human sound perception falls within a much more subjective realm, bringing with it physical and emotional components. Developing an awareness of our environmental soundscapes and their emotional and behavioral impacts [2] can help renew our relationship not only with our everyday microcosm but also with the wider natural world around us. Beyond our biological perception, questions abound as to how we might interpret sounds that exceed our bandwidth and what they might mean to us when juxtaposed with their origin. Made audible by amplification technologies and mapped to our biological bandwidth, could immersion into these ultra-low and ultra-high frequency wavefields provide us a glimpse of the hidden rhythms of the natural world?

The authors, an artist and geophysicist, present three different approaches to art-science projects, moving from “cooperation” to “cohabitation” and ending with “co-creation,” depicting hybrid models of art-science interdisciplinarity, particularly via sound art. The first section describes our cooperation in the digital realm to create an art installation using sonified seismic data collected in Antarctica. We then developed acoustic responses to vibrational data at a seismic deployment in New Mexico’s Jornada desert, envisioning a site-specific listening approach that would effectively merge art and science, restoring a human scale to more-than-human data. Topics and questions are raised by our art-science experiments that we hope will inspire new models of collaboration and participation in ever-more-urgent global responses to the climate crisis, revealing what we might call the voices of climate change.

Sound, sampled at a given point in space, can be viewed as time series data. That is, at any given point in time, the amplitude of the sound (its loudness) is the sum of many different frequencies arriving from different locations and different source types (e.g., think of listening to people speaking in a crowded room: The result is a summation of everyone’s conversations that the ear records in real time). Audio software will represent these time series as plots of sound amplitude versus time. This is the case for both acoustic (i.e., propagating only in the air) and seismic (propagating in the ground) wavefield time series.

In the quantitative realm, wave propagation between a source and a measurement point is broadly described through a differential mathematical framework aptly called the wave equation. This partial differential equation describes, at a high level, the impact of source location and type (explosion, turbulent wind, ocean waves) and the propagating environment (air, solid earth, etc.) on what is recorded at any point in space. Directly solving this equation for an arbitrary source and a complex heterogeneous medium (like the Earth) is extremely difficult, and in general assumptions must be made about both source and medium to explain any measurement of a wavefield at a point in space and time. In Earth sciences, wave propagation is analyzed through the seismic lens, and the natural environment itself produces a nearly constant hum of seismic “sound” at frequencies ranging from ultra-low planetary resonances (below 0.001 Hz) all the way into the acoustic range (above 100 Hz). The excitation of different seismic frequencies has different natural sources. For instance, the constant rhythmic beating of ocean waves on the coast creates certain specific seismic frequencies (with several bands between 0.01 and 1 Hz) named the microseism. At higher frequencies, seismic noise tends to be caused by wind friction, human noise, and transient sources like earthquakes. When the source of the seismic signal is statistically stable, it can be used to monitor temporal changes in structures, such as volcanic eruptive precursors, earthquake-related subsurface damage, permafrost thaw, etc.

For arid climes, including delicate ecosystems in the mid-western United States and the vast snowscapes of Antarctica, temporal monitoring in the context of climate change is a key objective of the scientific community, as exemplified by large-scale experiments such as the National Science Foundation-funded Ross Ice Shelf transect (Fig. 1, NSF #1246151). In some rare situations caused by unique interactions between atmosphere and surface, high seismic frequencies are persistently excited and can be responsive to very shallow earth processes, like surface erosion, melting (in the case of snow), and other subtle perturbations of these surface environments. Importantly, many of these observations feature time series that are strangely reminiscent of song-like patterns, only at frequencies below human hearing. These observations, as shown in Fig. 2, beg the question of whether such “almost human” seismic sounds, having spectrogram appearances qualitatively mirroring those of human vocal tracts, can evoke concurrent human responses, and whether the Earth itself speaks to us in some hidden language. On the flip side, it is through barely accessible human observations that scientists often imagine ways to reach beyond their limitations (e.g., are there colors below red? Above blue? Sounds below our hearing? Universes beyond what our eyes can see?). Thus tools developed by artists who are masters of interpretation and imagination can generate a feedback loop, with each party forcing the other out of their habitual sensory bubble.

In October 2018, Julien Chaput published preliminary research about ambient noise on the Ross Ice Shelf (roughly the size of France) in Antarctica [3], including strange, ghostlike frequency patterns that responded causally to every form of documented atmospheric force (storms, temperature swings, depositions/stripping of surface snow, other dynamic forces). The firn layer of ice sheets and ice shelves, consisting of the top tens of meters of loose to progressively more compact snow, serves as an insulating shield against fluctuations in temperature and other destructive environmental occurrences. Although it is somewhat resilient, progressive changes in the firn layer and its eventual compaction and melt signal the first steps toward destabilization and destruction of these large bodies of ice, which would herald rapid increases in global sea levels. By remapping two years of seismic data recorded by 34 seismographs to the audible range, Chaput discovered that the wave-trapping properties of Antarctic firn and the consequent ghostly spectral signatures can act to map a sort of acoustic “state of mind” of the whole snow and ice system. Chaput concluded that the strange dissonant song of the ice, as measured by the trapped seismic resonances, was nothing less than the tenuous song of the canary in the coal mine, giving us a sense of how ice sheets and shelves are resisting being denuded of their firn-layer skin by climate variability—or succumbing to it.

Following Chaput s published results, artist Sandra Volny developed a way to interpret this unusual phenomenon and turn it into an artistic project. Together, they listened to these vibrations trapped in glacial layers, later transcribing them into a sound installation.

As a sound artist exploring the sonics of soil as a vector to the past, Volny was interested in listening to these sound cores, attesting to the transformation of subterranean landscapes and bearing witness to disturbances in the soil’s history and to the tacit, 1,000-year-old memory of the glacial layers. In her artistic research, Volny has pursued a practice of “surviving aural spaces” [4] by giving form to an infrasonic epidermis where fossils are no longer minerals but sound masses [5], in a work titled Sonic Fossils (Fossiles sonores).

For this proj ect, Volny opted to recreate a spatial redistribution of the sounds so that the public could access this sound topography. In order to achieve it, Chaput created sound files that represent compressed 34-min remappings of two years of continuous seismic data, accompanied by images that map the stations and their sonic similarities representative of local phenomena such as storms, seasons, and so on. After discussing the sound files and exploring new algorithms with Chaput to heighten different sound qualities contained within the seismograms, Volny selected a sample of 14 sounds and used them to create an audiovisual installation based on a protocol she developed to expose matter to sound, using the sedimentation of sounds on various pigments.

The vibrations made audible by Chaput’s mathematical “sonification” process (Fig. 3 and supplemental material 1)—each one corresponding to a seismograph placed in Antarctica—are diffused via low-frequency woofers into 2-×-62-in water-filled steel plates placed directly on top of the loudspeakers, allowing the diffusion of the vibrations into water. Volny was inspired by the representation of cymatics—physical sound patterns—and the perfected protocol of Chladni plates by German physicist and musician Ernst Chladni (1756–1827), who experimented with vibrating plates to highlight the propagation of sound waves in solids (in his case sand), presenting the systematic visual patterns caused by nodal lines [6]. Volny replaced sand with water, allowing the waves captured in the ice of Antarctica to reappear, using water as a transduction medium. The plates resonated preferentially at specific frequencies and modes of resonances (e.g., notable wave patterns shown on the plate in Fig. 4), which were analytically calculated by Chaput for various plate dimensions to ensure maximum overlap between the sounds and the physical installation. The physicality of the sound waves is thus made visible, as different patterns appear on the surface of the water (as shown in supplemental video 1).

Through the repeated and ongoing exposure of matter to sound (protocol shown in Fig. 4) for a variable period of about one month (depending on the ambient conditions and temperature), the sound vibrations started sedimenting, petrifying, and eventually crystallizing on the steel plates, leaving an image inside the material of the acoustic wave’s vibratory model to which they were subjected. Each sound imprint or topography created by the sound on the steel is therefore unique and visually represents the sonic nuances captured by the probes, somehow chemically freezing the sound waves into matter. Throughout the process, Volny chose to emphasize the protocol using colored pigments that graphically accentuated the visual contrasts, bringing to the steel plates a gradation of nuances that reflect the sound tones in the recordings. In this work, Volny seeks not to systematize these figures in water but rather to let the voice of the ice express itself and appear in matter. The dimensions of the steel plates were chosen to be roughly the size of the artist, thus conveying a certain corporeality, a human scale for these more-than-human data (as shown in Color Plate C).

The process Volny employed to reveal these sonic fossils can be compared to that of developing an image or silver photograph, where the film is coated with an emulsion containing light-sensitive compounds. To reveal the latent image, still invisible to the eye, the film must be immersed into a bath containing the developer, which acts by reducing the crystals composited in the emulsion, producing a negative of the image. In fact, when a photograph is made it reveals the image that was already present on the film but invisible to perception. In Volny’s protocol, by revealing the visual appearance of these sound cores in matter, she produces a visual image containing subterranean sonic waves invisible to the eye and almost inaudible to the ear.

The captured and diffused vibrations allow for a perception of what the earth and our soil can teach us about the health of our ecosystems. Each sonic fossil is an imprint of sound in matter, an individual testament to its own passing, seeking to tie a body to its sonic memory. Through this work, Volny aims to create a memory against the dismemberment of time and space that accompanies the devastation at work in the Anthropocene era. Sonic Fossils witnesses surviving aural spaces by drawing the contours of the invisible, tracing the latent narratives contained in the background noise captured in Antarctica’s ice shelf.

The art-science cooperation involved in Sonic Fossils has resulted in the production of a material archive (as shown in Fig. 5) for the alteration of the Earth’s surface [7], taking form in an artistic installation and anchored in an ongoing story. It has further enabled the development of new scientific algorithms, perfected through the sonification provided by the scientist for the artwork, which allow for the modeling and analysis of spectral data in other science projects. However, the artist and scientist still noted some limitations to their joint process. In the case of this project, Volny developed the work and protocol after the published scientific results had been produced and conducted in the field by Chaput. Thus, the artist and scientist wished to conduct joint research during a seismic deployment in conjunction with data collection and protocol construction, in order to establish mutual art- science processes that could influence and respond to each other from the outset, perhaps producing joint results and helping renew such collaborative projects.

Like the Antarctic forays, an Army Research Lab-funded effort led by Chaput sought to develop passive seismic metrics relating subtle atmospheric forces (i.e., winds, rain, etc.) to direct alterations of arid morphologies, including estimates of airborne particles, erosion, and ultra-high frequency wind coupling with the surface (Fig. 6). Although a fundamentally different environment from Antarctica, the desert, with its presence of saltating sand particles—showing irregular bouncing movements—is similar in some ways to the former with its airborne snow ever present. For the Jornada project, however, a battery of concurrent environmental sensors was deployed, measuring particles, multiple tiers of wind speed and turbulence, humidity, pressure, and more. A primary goal of this project was also, for the first time, to attempt to detect and consequently model the seismic signals associated with saltating particles. This is an inherently daunting task due to the tiny scale of the particles and the consequently very high frequency range excited by their distributed impacts on the Earths surface (potentially outside the range of a typical seismic recording setup).

Volny chose to respond to the scientific research by addressing the transport of sand particles and dust, which is an important aspect of monitoring erosion, air quality, and the vulnerability of desert climates [8]. On site, she decided to build a listening instrument that would intercept saltation in response to surface phenomena such as wind pressure and erosion. The artist used a circular steel plate 7 in. in diameter and an accelerometer (a vibration sensor usually used for seismic or structural monitoring) to record direct sound vibrations (as shown in Fig. 7), seeking to capture and record windborne sand particles. In this process, the artist was inspired by the work pioneered by American sound artist Bill Fontana, who used accelerometers “to explore the musicality of sounds hidden inside structures” [9]. The ultra-high-sensitivity accelerometer was positioned on the steel plate and allowed the capture of a large quantity of sand particles. Listening to the noise transmitted by this instrument, we realized that these audio files would make it possible to quickly capture the distribution of sand grains over a vast territory. The background noise captured by the instrument, from the impacts of the sand grains to the movement of the wind on the metal membrane, provided a new range of information in frequencies not previously explored, possibly opening up new paths for scientific and acoustic research in the field.

The listening instrument therefore became a potential scientific research tool for monitoring erosion, air quality, and vulnerability in a desert climate, opening the door to seismic research in higher frequency spectra (up to 1,000 Hz) that would perhaps allow the sound to be processed, observed, and eventually correlated directly with periods of high particle flux. Listening to the movement of sand particles and dust in the Jornada Desert (supplemental audio 2), we also opened up new potentials for art-science collaboration, where the act of listening would become in itself an important new mode of scientific Earth monitoring, which is usually dominated by computational techniques and processes. Such experimentation also became fertile ground for a dialogue between artist and scientist: We plan to cocreate a site-specific listening approach, effectively merging art and science based on their results. As a testimony of this in situ experience, Volny printed the sound of the desert on a 7-in vinyl record, with the recording instrument referenced in the title The Whole Desert on a 7-inch. The immensity of the Jornada desert and its transformations—perceived through the rhythmic modulations of the grains of sand—are brought to human scale, with the objective of preserving traces of the living landscape and its current erosion and disappearance.

Throughout our collaboration, the artist and scientist used sound not only as evidence of the urgency of climate change, contained in seismic and acoustic information, but also to convey feeling and meaning (on a human scale) to the voice emitted by the Earth in these extreme environments under pressure. We developed an attuned sonic approach that uses the act of listening as a tool to better understand our environment, in a form of “knowing-with and knowing-by-the audible” [10].

Over the course of our first collaboration as developed for Sonic Fossils, Volny drew on the scientific findings, namely the seismic sensitivity to various forms of climatic influence in fragile arid climes, to develop an artistic protocol. Therefore, art contributed to the development of the scientific research via the novel algorithms necessary for the artistic project; scientific knowledge and procedures then provided key elements for the realization of the elements necessary for the formation of the artistic installation. Of course, there were still limitations to our collaborations: We did not directly produce a body of research or a common artistic production. Following a logic of intensification, we initiated a common on-site protocol in the second project, The Whole Desert on a 7-inch, which resulted in the joint production of artwork and scientific research in the field. For the Jornada effort, the artistic and scientific instruments were collocated at the beginning of the process, opening up the possibility of an in situ art-science cocreation facilitated by the cohabita tion of the tools and the production of a common device emerging for on-site joint protocols.

Through its experimental approach and particular disciplinary tools, art can thus potentially contribute to the foundation of new scientific evidence, while science can benefit art projects in its specific field deployments, tools, and findings. The listening approach also opens a new way for seismic research to incorporate sonic data, moving away from a purely visual paradigm in the data sciences. This porosity of sound art into art-science opens up new possibilities for artists and scientists to collaborate. Several key questions, however, remain: Could the data from the instruments primed in the desert be compared and/or used in parallel with the seismic data collected by the scientist, with overlapping spectral sensitivities? Would it be possible to cross-reference seismic and acoustic data? Such a setup also has various challenges, such as instrumental collocation during high throughput periods (such as gale force winds, common in the Jornada desert), as recording data from an art installation in the field under extreme conditions can be complicated. Nevertheless, this new approach involving listening and sound art in the context of art-science projects could pave a new path for cocreation, potentially restoring a dynamic experience that in the future might be shared with the public as site-specific installations. Accessing the voices of the soil remains an ever-evolving process, but one that can help reconnect us with those extreme environments currently undergoing rapid and often violent change.

Sandra Volny thanks Fonds de recherche Québec—Société et Culture for their generous support as well as Julien Chaput and François-Joseph Lapointe. Research for this study was funded in part by Army Research Office grant #Wc11NF2020174 and by Chaput’s startup funds.