Over the last two decades, post-modern geopolitical debates have raged concerning the ostensible dissolution of territories, boundaries, and sovereignty in a globalized world where the internet and other communication media have caused a time-space compression. Following these debates, our understanding of boundaries as fixed delineators underwent radical changes: no longer the strict dividers of territory, boundaries are now seen not only as permeable, but, rather as social processes. Coterminous with these debates have been others in critical cartography surrounding the objectivity of remotely sensed imagery, and relatedly, whether geographic information systems traffic in data or more subjectively mediated information. In the context of these debates over boundaries, permeability, and objectivity, I believe it is fascinating to compare both media coverage, and conversely the (re)production, of natural disasters. Ironically, the intersecting point for analyses of visibility, invisibility, and legibility in the context of these disasters are the boundaries of radiation itself.
As a very brief introduction, remote sensing is the recording of data about an object from a sensor that is not in direct contact with the object. Similar in a way to photographic film, remotely sensed images are produced through the capturing of electromagnetic radiation. Geographers use remotely sensed imagery for a wide variety of purposes, including monitoring temporal changes in land cover, and modeling sea-level change. Critical geographers have also utilized and explored the usage of remotely sensed imagery, such as in the production and contestation of particular land change narratives. Other critical scholarship has explored the intersection of scale and boundaries in remotely quantifying spatial phenomena. Comparing the BP oil spill in the Gulf with the radiation leaks in Japan is particularly instructive, as it points to the centrality of borders as mediating the visibility, and conversely invisibility of certain types of disasters; additionally, such a comparison of borders also highlights the temporal variable through which certain visible disasters become invisible, and those that are invisible become visible. Take the BP oil spill, for example, for months satellite imagery was extensively utilized to help visualize and anticipate the spreading boundaries of the oil slick. With the spectral response of oil easily distinguishable from water, both scientists, and importantly the lay public were able to delineate and thus visualize the implications of the spill. In other words, the easily distinguishable natural boundaries of the spill enabled the visualization and production of the spill as a disaster. Ironically, given that electromagnetic radiation is the physical force that enables the production of remotely sensed imagery, radiation emanating from an explosion at nuclear reactor is a different story. Spectral sensors, at present, are not equipped to determine the spreading extent of this type of radiation. While thermal radiation, such as from a meltdown, for example, can be identified, radioactive isotopes that are air or waterborne are invisible. Or at least their current manifestations are invisible. What is particularly intriguing to me is how the variable of time becomes a factor in the scientific analysis, media portrayal, and the public understanding of visible and invisible disasters. Additionally, in the context of ongoing debates about the social production of borders, it is fascinating how boundaries both coalesce and disperse over time. It has been a quarter century since the nuclear meltdown at Chernobyl; yet, the invisible and toxic cloud of radiation that was carried in the air and through the water has over time left visible spatial artifacts. Using multi-temporal Landsat imagery for example, scientists are capable of tracking forest regeneration following the abandonment of agricultural land.
In other words, the boundaries of what was a largely invisible disaster have become visible. By contrast, over even short periods of time, the incorporation and dispersal of oil within the Gulf stream has rendered the highly visible BP oil spill largely invisible—if not to the most accurate spectral sensors, than at least to the public eye. What these ruminations and imagery point to is how certain geographic phenomena—both anthropogenic and natural—are made visible or are inherently invisible, if only temporally, before other natural processes transform their visibility. For critical geographers, the differential production of disasters as (in)discernible and (un)bordered phenomenon, and how remotely sensed imagery mediate the related public and institutional responses are increasingly fruitful grounds for continued attention.
