Browsing by Subject "Global Warming"
Results Per Page
Sort Options
Item Open Access Climate drives the geography of marine consumption by changing predator communities.(Proceedings of the National Academy of Sciences of the United States of America, 2020-11) Whalen, Matthew A; Whippo, Ross DB; Stachowicz, John J; York, Paul H; Aiello, Erin; Alcoverro, Teresa; Altieri, Andrew H; Benedetti-Cecchi, Lisandro; Bertolini, Camilla; Bresch, Midoli; Bulleri, Fabio; Carnell, Paul E; Cimon, Stéphanie; Connolly, Rod M; Cusson, Mathieu; Diskin, Meredith S; D’Souza, Elrika; Flores, Augusto AV; Fodrie, F Joel; Galloway, Aaron WE; Gaskins, Leo C; Graham, Olivia J; Hanley, Torrance C; Henderson, Christopher J; Hereu, Clara M; Hessing-Lewis, Margot; Hovel, Kevin A; Hughes, Brent B; Hughes, A Randall; Hultgren, Kristin M; Jänes, Holger; Janiak, Dean S; Johnston, Lane N; Jorgensen, Pablo; Kelaher, Brendan P; Kruschel, Claudia; Lanham, Brendan S; Lee, Kun-Seop; Lefcheck, Jonathan S; Lozano-Álvarez, Enrique; Macreadie, Peter I; Monteith, Zachary L; O’Connor, Nessa E; Olds, Andrew D; O’Leary, Jennifer K; Patrick, Christopher J; Pino, Oscar; Poore, Alistair GB; Rasheed, Michael A; Raymond, Wendel W; Reiss, Katrin; Rhoades, O Kennedy; Robinson, Max T; Ross, Paige G; Rossi, Francesca; Schlacher, Thomas A; Seemann, Janina; Silliman, Brian R; Smee, Delbert L; Thiel, Martin; Unsworth, Richard KF; van Tussenbroek, Brigitta I; Vergés, Adriana; Yeager, Mallarie E; Yednock, Bree K; Ziegler, Shelby L; Duffy, J EmmettThe global distribution of primary production and consumption by humans (fisheries) is well-documented, but we have no map linking the central ecological process of consumption within food webs to temperature and other ecological drivers. Using standardized assays that span 105° of latitude on four continents, we show that rates of bait consumption by generalist predators in shallow marine ecosystems are tightly linked to both temperature and the composition of consumer assemblages. Unexpectedly, rates of consumption peaked at midlatitudes (25 to 35°) in both Northern and Southern Hemispheres across both seagrass and unvegetated sediment habitats. This pattern contrasts with terrestrial systems, where biotic interactions reportedly weaken away from the equator, but it parallels an emerging pattern of a subtropical peak in marine biodiversity. The higher consumption at midlatitudes was closely related to the type of consumers present, which explained rates of consumption better than consumer density, biomass, species diversity, or habitat. Indeed, the apparent effect of temperature on consumption was mostly driven by temperature-associated turnover in consumer community composition. Our findings reinforce the key influence of climate warming on altered species composition and highlight its implications for the functioning of Earth's ecosystems.Item Open Access Comparing the model-simulated global warming signal to observations using empirical estimates of unforced noise.(Sci Rep, 2015-04-21) ◦Brown, P.T., W. Li, E.C. Cordero, S.A. MaugetThe comparison of observed global mean surface air temperature (GMT) change to the mean change simulated by climate models has received much public and scientific attention. For a given global warming signal produced by a climate model ensemble, there exists an envelope of GMT values representing the range of possible unforced states of the climate system (the Envelope of Unforced Noise; EUN). Typically, the EUN is derived from climate models themselves, but climate models might not accurately simulate the correct characteristics of unforced GMT variability. Here, we simulate a new, empirical, EUN that is based on instrumental and reconstructed surface temperature records. We compare the forced GMT signal produced by climate models to observations while noting the range of GMT values provided by the empirical EUN. We find that the empirical EUN is wide enough so that the interdecadal variability in the rate of global warming over the 20(th) century does not necessarily require corresponding variability in the rate-of-increase of the forced signal. The empirical EUN also indicates that the reduced GMT warming over the past decade or so is still consistent with a middle emission scenario's forced signal, but is likely inconsistent with the steepest emission scenario's forced signal.Item Open Access Devil in the Water, Lights on the Mountain: Climate Change in Andean Peru(2018) Turevon, Elena S.This dissertation examines everyday life and storytelling in Peru's Huaylas Valley: a transnational mining hub beneath melting Andean glaciers. During one year of ethnographic fieldwork, I listened to citydwellers and villagers narrate personal stories, gory rumors, and mythic tales: of a ruined Inca city that glows at night, a disappearing water devil, wild lakes turning tame, a Christ whose powers are shrinking. Rather than evincing ontological alterity, Huaylas stories reveal distinctive capitalist imaginaries and their ancient genealogies. They convey a popular sense of marginalization at a time of rapid, mineral-fueled growth, along with high hopes for a wealthy, developed future. And, their motifs and imagery attest to centuries of intercultural exchange, showing how capitalism took root in the Andes through indigenous cosmology, even as it developed through American colonization. Today, storytellers imagine and relate to their once-animate landscape as a banal means of accumulation, enlivening it through modern dreams that herald this future by banishing the superfluous—fantastic beings, and even themselves— from their Valley. If only by aspiration, then, storytellers in the Huaylas Valley form part of a planetary capitalist culture that accelerates global warming, raises mass living standards, and circulates fantasies of material redemption. While climate change is typically construed as a problem for scientists and consumers to solve, this dissertation shows instead that global warming is a historical, cultural problem about the ends that more and more of humankind imagines, and strives to achieve.
Item Open Access Increased labor losses and decreased adaptation potential in a warmer world.(Nature communications, 2021-12) Parsons, Luke A; Shindell, Drew; Tigchelaar, Michelle; Zhang, Yuqiang; Spector, June TWorking in hot and potentially humid conditions creates health and well-being risks that will increase as the planet warms. It has been proposed that workers could adapt to increasing temperatures by moving labor from midday to cooler hours. Here, we use reanalysis data to show that in the current climate approximately 30% of global heavy labor losses in the workday could be recovered by moving labor from the hottest hours of the day. However, we show that this particular workshift adaptation potential is lost at a rate of about 2% per degree of global warming as early morning heat exposure rises to unsafe levels for continuous work, with worker productivity losses accelerating under higher warming levels. These findings emphasize the importance of finding alternative adaptation mechanisms to keep workers safe, as well as the importance of limiting global warming.Item Open Access The Effects of Dredging and Trawling on Continential Shelf Sediment Biochemistry(2003) Shively, Eliza BlueThe effects of fishing gear on the seabed are well documented. This study specifically investigates the use of dredges and trawls, which are two of the most commonly towed fishing gears both in the U.S. and abroad. These gears are both "active" bottom-contact fishing gear, which means large bag nets, weighing nearly 1500 pounds empty, are towed by fishing vessels and dragged across the seafloor to catch demersal species such as oyster, crabs, clams, halibut, flounder, cod, and shrimp. The effects of these gears on benthic habitats have been much studied and include fish and invertebrate mortality (target and non-target species), loss of habitat, reduced habitat complexity and community diversity, and a reduction in productivity. Conversely, the impacts of dredging and trawling on sediment biogeochemistry have been seldom considered, but could have far-reaching implications when experimental results are extrapolated to larger scales. This study extensively reviews the current and available research on the effects of mobile fishing gear use on sediment biogeochemistry, processes, and sedimentary rnicroenvironments. Specifically, I wanted to answer the following questions: With the assumption ofa high frequency ofdredging and trawling on the world's continental shelves, does mobile fishing gear resuspend and subsequently oxidize carbon that would otherwise be stored in shelf sediments? If so, could this be an unrecognized and significant source ofcarbon dioxide to the water column and consequently the atmosphere thereby contributing to global warming? An extensive literature review yielded only four scientific studies addressing the biogeochemical implications (for C, N, P, and Si) but none of them tackled the effects to carbon beyond the experimental scale. Consequently, with the assistance of Dr. Richard Barber (Duke University), I created a carbon box model to estimate the carbon contribution (using a 1m^2 study area) induced by dredging and trawling relative to a background sea surface carbon value of 2000mM C/m^3. The goal was to establish an upper bound estimate (or maximum) for the amount of CO2 that dredging and trawling could potentially contribute to the atmosphere and to global warming processes. Calculations were done for 50m, 100m, and 200m water depths using total export production values of lOgC/m^2 and 50gC/m^2 and with values of 10% and 50% of that production reaching the seafloor. Additionally, we assumed that 100% of the C reaching the seafloor was oxidized and trapped in the sediments and 100% of that was resuspended by the fishing gear. The value of lOgC/m^2 represents a representative estimate to how much carbon sinks to substrate, while 50gC/m^2 is wildly high and was used to establish an upper bounds for the estimate. The results yielded an approximately 1.5% addition to the carbon in sea surface waters and subsequently the atmosphere; this illustrates that although there is a net transfer of carbon dioxide from the water column to the atmosphere, dredging and trawling is not a significant and unaccounted for source of CO2 and thus does not influence global warming.