57 research outputs found
Dealing with the Trauma of Undiagnosed Dyslexia
The theme of my Master’s by research is an investigation into the condition and effects of dyslexia on one’s personality, academic experience and professional growth. I wish to examine and acknowledge the effects dyslexia has on an individual’s ability to learn and grow in a “typical” twenty-first-century society. I intend also to highlight the emotional impact this disability can have on a person’s sense of self and how they develop through childhood. I hope to demonstrate the link dyslexia has in fostering a visual form of thinking and expression. I also hope to evaluate how one’s dyslexia reveals itself in so many ways in everyday tasks one performs as an active participant in society. I am now in my fifties and have spent most of my life hiding my dyslexia from those around me. The reason for this is that hated the feelings of embarrassment and inadequacy it caused. No one likes making mistakes, but it was especially traumatic in my early childhood as I grew up in a time in Ireland when there was an ignorance in our educational system when it came to informed knowledge around neurodiversity disabilities, such as dyslexia. Therefore, in order to do this research I am choosing to use myself and my experiences as a type of autoethnographic case study. Autoethnographic research is about giving an individual the opportunity to deeply and meaningfully reflect on their own story, in order to better understand, know and interpret their personal and cultural experiences. Thus, it is a research methodology that helps me explore myself. Consequently, I will be an active participant in analysing the impact of dyslexia on my education and personal life, while also demonstrating the link to my creative abilities as a graphic designer, typographer, photographer and fine art printmaker. It will explore the impact, limitations and advantages that dyslexia have brought into my life and career
Subglacial valleys preserved in the highlands of south and east Greenland record restricted ice extent during past warmer climates
The Greenland Ice Sheet is a key contributor to contemporary global sea level rise, but its long-term history and response to episodes of warming in Earth's geological past remain uncertain. The terrain covered by the ice sheet comprises ∼ 79 % of Greenland and ∼ 1.1 % of the Earth's land surface and contains geomorphological records that may provide valuable insights into past ice-sheet behaviour. Here we use ice surface morphology and radio-echo sounding data to identify ice-covered valleys within the highlands of southern and eastern Greenland and use numerical ice-sheet modelling to constrain the climatological and glaciological conditions responsible for valley incision. Our mapping reveals intricate subglacial valley networks with morphologies that are indicative of substantial glacial modification of an inherited fluvial landscape, yet many of these valleys are presently situated beneath cold-based, slow-moving (i.e. non-erosive) ice. We use the morphology of the valleys and our simple ice-sheet model experiments to infer that incision likely occurred beneath erosive mountain valley glaciers during one or more phases of Greenland's glacial history when ice was restricted to the southern and eastern highlands and when Greenland's contribution to barystatic sea level was up to +7 m relative to today. We infer that this valley incision primarily occurred prior to the growth of a continental-scale ice sheet, most likely during the late Miocene (ca. 7–5 Ma) and/or late Pliocene (ca. 3.6–2.6 Ma). Our findings therefore provide new data-based constraints on early Greenland Ice Sheet extent and dynamics that can serve as valuable boundary conditions in models of regional and global palaeoclimate during past warm periods that are important analogues for climate change in the 21st century and beyond
Modelling the enigmatic Late Pliocene Glacial Event: Marine Isotope Stage M2
The Pliocene Epoch (5.2 to 2.58Ma) has often been targeted to investigate the nature ofwarmclimates. However,
climate records for the Pliocene exhibit significant variability and show intervals that apparently experienced a
cooler than modern climate. Marine Isotope Stage (MIS) M2 (~3.3 Ma) is a globally recognisable cooling event
that disturbs an otherwise relatively (compared to present-day) warm background climate state. It remains
unclear whether this event corresponds to significant ice sheet build-up in the Northern and Southern
Hemisphere. Estimates of sea level for this interval vary, and range from modern values to estimates of 65 m
sea level fall with respect to present day. Here we implement plausibleM2 ice sheet configurations into a coupled
atmosphere–ocean climate model to test the hypothesis that larger-than-modern ice sheet configurations may
have existed at M2. Climate model results are compared with proxy climate data available for M2 to assess the
plausibility of each ice sheet configuration. Whilst the outcomes of our data/model comparisons are not in all
cases straight forward to interpret, there is little indication that results from model simulations in which
significant ice masses have been prescribed in the Northern Hemisphere are incompatible with proxy data from
the North Atlantic, Northeast Arctic Russia, North Africa and the Southern Ocean. Therefore, our model results do
not preclude thepossibilityof the existenceof larger icemasses duringM2 in the Northern or SouthernHemisphere.
Specifically they are not able to discount the possibility of significant icemasses in the Northern Hemisphere during
the M2 event, consistent with a global sea-level fall of between 40 m and 60 m. This study highlights the general
need for more focused and coordinated data generation in the future to improve the coverage and consistency in
proxy records for M2, which will allow these and future M2 sensitivity tests to be interrogated further
The warm winter paradox in the Pliocene northern high latitudes
Reconciling palaeodata with model simulations of the Pliocene climate is essential for understanding a world with atmospheric CO2 concentration near 400 ppmv (parts per million by volume). Both models and data indicate an amplified warming of the high latitudes during the Pliocene; however, terrestrial data suggest that Pliocene northern high-latitude temperatures were much higher than can be simulated by models.
We focus on the mid-Pliocene warm period (mPWP) and show that understanding the northern high-latitude terrestrial temperatures is particularly difficult for the coldest months. Here the temperatures obtained from models and different proxies can vary by more than 20 ∘C. We refer to this mismatch as the “warm winter paradox”.
Analysis suggests the warm winter paradox could be due to a number of factors including model structural uncertainty, proxy data not being strongly constrained by winter temperatures, uncertainties in data reconstruction methods, and the fact that the Pliocene northern high-latitude climate does not have a modern analogue. Refinements to model boundary conditions or proxy dating are unlikely to contribute significantly to the resolution of the warm winter paradox.
For the Pliocene high-latitude terrestrial summer temperatures, models and different proxies are in good agreement. Those factors which cause uncertainty in winter temperatures are shown to be much less important for the summer. Until some of the uncertainties in winter high-latitude Pliocene temperatures can be reduced, we suggest a data–model comparison should focus on the summer. This is expected to give more meaningful and accurate results than a data–model comparison which focuses on the annual mean
The role of atmospheric CO2 in controlling sea surface temperature change during the Pliocene,
We present the role of CO2 forcing in controlling Late Pliocene sea surface temperature (SST) change using six models from Phase 2 of the Pliocene Model Intercomparison Project (PlioMIP2) and palaeoclimate proxy data from the PlioVAR working group. At a global scale, SST change in the Late Pliocene relative to the pre-industrial is predominantly driven by CO2 forcing in the low and mid-latitudes and non-CO2 forcing in the high latitudes. We find that CO2 is the dominant driver of SST change at the vast majority of proxy data sites assessed (17 out of 19), but the relative dominance of this forcing varies between all proxy sites, with CO2 forcing accounting for between 27 % and 82 % of the total change seen. The dearth of proxy data sites in the high latitudes means that only two sites assessed here are predominantly forced by non-CO2 forcing (such as changes to ice sheets and orography), both of which are in the North Atlantic Ocean.We extend the analysis to show the seasonal patterns of SST change and its drivers at a global scale and at a site-specific level for three chosen proxy data sites. We also present a new estimate of Late Pliocene climate sensitivity using site-specific proxy data values. This is the first assessment of site-specific drivers of SST change in the Late Pliocene and highlights the strengths of using palaeoclimate proxy data alongside model outputs to further develop our understanding of the Late Pliocene. We use the best available proxy and model data, but the sample sizes remain limited, and the confidence in our results would be improved with greater data availability
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The PRISM4 (mid-Piacenzian) paleoenvironmental reconstruction
The mid-Piacenzian is known as a period of relative warmth when compared to the present day. A comprehensive understanding of conditions during the Piacenzian serves as both a conceptual model and a source for boundary conditions as well as means of verification of global climate model experiments. In this paper we present the PRISM4 reconstruction, a paleoenvironmental reconstruction of the mid-Piacenzian ( ∼ 3 Ma) containing data for paleogeography, land and sea ice, sea-surface temperature, vegetation, soils, and lakes. Our retrodicted paleogeography takes into account glacial isostatic adjustments and changes in dynamic topography. Soils and lakes, both significant as land surface features, are introduced to the PRISM reconstruction for the first time. Sea-surface temperature and vegetation reconstructions are unchanged but now have confidence assessments. The PRISM4 reconstruction is being used as boundary condition data for the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) experiments
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The Pliocene Model Intercomparison Project (PlioMIP) Phase 2: scientific objectives and experimental design
The Pliocene Model Intercomparison Project (PlioMIP) is a co-ordinated international climate modelling initiative to study and understand climate and environments of the Late Pliocene, as well as their potential relevance in the context of future climate change. PlioMIP examines the consistency of model predictions in simulating Pliocene climate and their ability to reproduce climate signals preserved by geological climate archives. Here we provide a description of the aim and objectives of the next phase of the model intercomparison project (PlioMIP Phase 2), and we present the experimental design and boundary conditions that will be utilized for climate model experiments in Phase 2. Following on from PlioMIP Phase 1, Phase 2 will continue to be a mechanism for sampling structural uncertainty within climate models. However, Phase 1 demonstrated the requirement to better understand boundary condition uncertainties as well as uncertainty in the methodologies used for data–model comparison. Therefore, our strategy for Phase 2 is to utilize state-of-the-art boundary conditions that have emerged over the last 5 years. These include a new palaeogeographic reconstruction, detailing ocean bathymetry and land–ice surface topography. The ice surface topography is built upon the lessons learned from offline ice sheet modelling studies. Land surface cover has been enhanced by recent additions of Pliocene soils and lakes. Atmospheric reconstructions of palaeo-CO2 are emerging on orbital timescales, and these are also incorporated into PlioMIP Phase 2. New records of surface and sea surface temperature change are being produced that will be more temporally consistent with the boundary conditions and forcings used within models. Finally we have designed a suite of prioritized experiments that tackle issues surrounding the basic understanding of the Pliocene and its relevance in the context of future climate change in a discrete way.</p
Large-scale features of Pliocene climate: results from the Pliocene Model Intercomparison Project
Climate and environments of the mid-Pliocene warm period (3.264 to 3.025 Ma) have been extensively studied. Whilst numerical models have shed light on the nature of climate at the time, uncertainties in their predictions have not been systematically examined. The Pliocene Model Intercomparison Project quantifies uncertainties in model outputs through a coordinated multi-model and multi-model/data intercomparison. Whilst commonalities in model outputs for the Pliocene are clearly evident, we show substantial variation in the sensitivity of models to the implementation of Pliocene boundary conditions. Models appear able to reproduce many regional changes in temperature reconstructed from geological proxies. However, data/model comparison highlights that models potentially underestimate polar amplification. To assert this conclusion with greater confidence, limitations in the time-averaged proxy data currently available must be addressed. Furthermore, sensitivity tests exploring the known unknowns in modelling Pliocene climate specifically relevant to the high latitudes are essential (e.g. palaeogeography, gateways, orbital forcing and trace gasses). Estimates of longer-term sensitivity to CO2 (also known as Earth System Sensitivity; ESS), support previous work suggesting that ESS is greater than Climate Sensitivity (CS), and suggest that the ratio of ESS to CS is between 1 and 2, with a "best" estimate of 1.5
Orbital, tectonic and oceanographic controls on Pliocene climate and atmospheric circulation in Arctic Norway
During the Pliocene Epoch, a stronger-than-present overturning circulation has been invoked to explain the enhanced warming in the Nordic Seas region in comparison to low to mid-latitude regions. While marine records are indicative of changes in the northward heat transport via the North Atlantic Current (NAC) during the Pliocene, the long-term terrestrial climate evolution and its driving mechanisms are poorly understood. We present the first two-million-year-long Pliocene pollen record for the Nordic Seas region from Ocean Drilling Program (ODP) Hole 642B, reflecting vegetation and climate in Arctic Norway, to assess the influence of oceanographic and atmospheric controls on Pliocene climate evolution. The vegetation record reveals a long-term cooling trend in northern Norway, which might be linked to a general decline in atmospheric CO2 concentrations over the studied interval, and climate oscillations primarily controlled by precession (23 kyr), obliquity (54 kyr) and eccentricity (100 kyr) forcing. In addition, the record identifies four major shifts in Pliocene vegetation and climate mainly controlled by changes in northward heat transport via the NAC. Cool temperate (warmer than present) conditions prevailed between 5.03–4.30 Ma, 3.90–3.47 Ma and 3.29–3.16 Ma and boreal (similar to present) conditions predominated between 4.30–3.90 Ma, 3.47–3.29 and after 3.16 Ma. A distinct decline in sediment and pollen accumulation rates at c. 4.65 Ma is probably linked to changes in ocean currents, marine productivity and atmospheric circulation. Climate model simulations suggest that changes in the strength of the Atlantic Meridional Overturning Circulation during the Early Pliocene could have affected atmospheric circulation in the Nordic Seas region, which would have affected the direction of pollen transport from Scandinavia to ODP Hole 642B
The transient response of ice volume to orbital forcing during the warm Late Pliocene
Examining the nature of ice sheet and sea level response to past episodes of enhanced greenhouse gas forcing may help constrain future sea level change. Here, for the first time, we present the transient nature of ice sheets and sea level during the late Pliocene. The transient ice sheet predictions are forced by multiple climate snapshots derived from a climate model set up with late Pliocene boundary conditions, forced with different orbital forcing scenarios appropriate to two Marine Isotope Stages (MISs), MIS KM5c, and K1. Our results indicate that during MIS KM5c both the Antarctic and Greenland ice sheets contributed to sea level rise relative to present and were relatively stable. Insolation forcing between the hemispheres was out of phase during MIS K1 and led to an asynchronous response of ice volume globally. Therefore, when variations of precession were high, inferring the behavior of ice sheets from benthic isotope or sea level records is complex
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