Wave modelers in recent years have become increasingly aware of these matters-and a thoroughgoing epistemological critique of wave theory from the north would dig into the histories of the kinds of waves that were early on relevant to colonial desires for speed in seafaring. In 2014, Nature Climate Change published on mis-estimations of southern sea surface temperatures in most climate models, assuming too-low cloud cover over southern oceans (Wang et al. In fact, back in the year 2000, one European ocean model had been found to underestimate wave heights by 20 percent in the Southern Hemisphere (Janssen 2000). If theory, in its etymology, points us to the ancient Greek for “to see” ( θεωρός ), wave spectra are often seen through theory from the north. Such data emerges from computer models trained on wind-speeds from northern seas-and, in fact, often, from the North Sea. Higher wave heights in the Southern Hemisphere, then, are not so much “unprocessed data” from the south as data made legible through theory from the north. Wave measurements are turned into statistics and fed into descriptive and predictive computer models, making known wave height data a layering of the actual and the virtual. Wave heights are measured by buoys and satellites, whose emplaced distributions, at sea and in orbit, are shaped by political, economic, and military histories-with Europe and the United States being dominant players in this domain. How do oceanographers arrive at knowledge of increasing wave heights? Answer: through environmental observation and computer modeling (Helmreich 2014). Today’s Anthropocene, Plantationocene, Capitalocene, and Military-ocene oceans (see DeLoughrey 2019)-overfished, acidifying, warming, irradiated-are nothing if not hybrid nature-culture, material-semiotic forces that churn political-economic processes into the stir, surge, and spray of the sea. The futures that waves bring are not, of course, only environmentally animated ones, but also curled together with the effects of human overreaching, greed, and denial. Waves, of course, are often treated as symbols for fast arriving, inevitable futures-think of any number of wave disaster movies (Helmreich 2018). Think, then, of the rising wave heights in the Oceanic South as phenomena that underscore the changes coming in the global ocean-stronger storms, surges that inundate coastal communities. reservoirs of raw fact” (Comaroff 2012, 1), rather than, as they might instead be, prescient pointers to the directions that world affairs might be taking. The Comaroffs suggest that the Global South and its geographies have been treated in social theory as “a place of parochial wisdom, of antiquarian traditions, of exotic ways and means,” and, “above all, of unprocessed data. “The southern region of the globe is most readily conceived of as what is bound by the longitudinal lines of imperial and metropolitan domination or described by the curvier Brandt Line as comprising the ‘poorer nations.’ But it might also be defined by the relatively vast maritime expanses that distinguish the Southern Hemisphere.”-(Samuelson and Lavery 2019, 37). Meg Samuelson and Charne Lavery seek to develop a parallel account for what they call “The Oceanic South” (2019). In Theory from the South (2012), Jean and John Comaroff argue that Northern (i.e., European and American) social histories, tendencies, and theories may be inadequate to apprehending the motivating forces of the world today, which they see most starkly represented in the countries of the Global South. The Southern Hemisphere, with more “oceanicity” than the north, may also be a harbinger of what is to come (and what is, in fact, already happening) on an increasingly climate-morphing, sea-surfaced planet. This is significant for maritime worlds in the Southern Hemisphere, with bigger waves arriving at harbors and coastlines, but also elsewhere, as the Southern Ocean is the source for many swell patterns worldwide.
And although rising wave heights are also manifesting in the Northern Hemisphere, particularly in high latitude locations, amplification in southern seas is more intense because the Southern Hemisphere hosts more uninterrupted ocean surface than the northern, giving waves longer fetches over which to grow in size and strength. According to a 2019 report in Science, wind-speed increases over the Earth’s southernmost oceans-a consequence of surface warming-have led to amplifications in wave height of some 30 centimeters since 1985, for the largest 10 percent of waves (Barras 2019). The distribution of worldwide wind wave heights is transforming.