International Assessments of the Vulnerability of the Coastal Zone to Climate Change, Including an Australian Perspective

Australia, and considers global, and in some cases national, assessments of vulnerability to climate change to evaluate the implications for the Australian coast, or to assess the applicability of particular approaches and methods to Australia. Climate change vulnerability assessment aims at assisting policymakers in adequately responding to the challenge of climate change by investigating how projected changes in the Earth\u27s climate may affect natural systems and human activities. Generally studies consider, exposure or susceptibility of natural coastal systems, the effect on socio-economic systems (“impact assessment”), and/or how human actions may reduce adverse effects of climate change on those systems or activities (“adaptation assessment”, a measure of adaptive capacity). The framework for a climate change vulnerability assessment depends on the system under consideration, stressors, responses (effects), and actions (adaptation). It is important that each assessment is undertaken at the relevant spatial and temporal scales, and the results are often appropriate only at those scales

Properties of Pumice Lightweight Aggregate

The use of Lightweight concretes has gained acceptance and popularity world wide in the recent years in the construction and development of both the infrastructure and residential buildings. The properties of volcanic pumice lightweight aggregates obtained from Longonot in Mai Mahiu area in Kenya was experimentally investigated and this study presents the experimental results of the investigation. Three samples of the lightweight aggregates were investigated and their properties compared with those of the conventional normal aggregate. In this experimental investigation the physical and mechanical properties of the aggregates were investigated. Properties such as bulk density, water absorption, grading and aggregate impact crushing value were determined. Keywords: Pumice; Lightweight Aggregate, Bulk Density, Gradin

Gum Arabic as an Admixture in Modified Concrete Mixed with Calcined Kaolin

The use of calcined kaolin (CK) as a cementitious material in construction has attracted the interest of various researchers due to its environmental, mechanical, and physical qualities, all of which contribute to the lowering of cement usage. Studies have reported numerous problems associated with its use in concrete, apart from the ecological benefit that CK can provide. For instance, there is an issue of increased water demand due to smaller particle size, which generates much more heat in concrete, which has a detrimental effect on the mechanical and physical properties of concrete. This paper presents the analysis of an investigation aimed at using gum Arabic (GA) as a biopolymer admixture and calcined kaolin as a partial replacement of cement to improve the mechanical properties and durability of concrete. GA proportions ranged from 0 to 1% by weight of cement. Calcined kaolin (CK) was used to replace 5, 10, 15, 20, 25, and 30% of the cement content, respectively. Compressive strength, splitting tensile strength, density, strength loss, and weight loss tests were all performed to validate the structural performance of the modified concrete. The compressive tests, performed after 28 days from the time the mixture was made, demonstrated that the maximum percentage of CK that could replace cement without affecting the mechanical properties of concrete was 20%. Beyond 20%, concrete does not exhibit good compressive strength properties. The results also revealed decreased compressive strength and splitting tensile strength tests as the percentage of CK increased. After 56 days, compressive strength at 5% CK and 10% CK increased slightly by 0.743% and 1.162 %, respectively, compared to the control sample. The inclusion of 0.8%GA increased the compressive strength by 8.94% compared to the control sample (0%CK + 0%GA + 100%OPC) after 56 days. The results of durability tests showed that 0.6% GA had a higher compressive strength than other percentages containing GA. Doi: 10.28991/CEJ-2022-08-05-010 Full Text: PD

Internationalization of the curriculum through student-led climate change teaching activity

Internationalization of the curriculum is important in today's globalized environment, with the increasingly interdisciplinary nature of complex issues, such as climate change, requiring students to think beyond their disciplinary and cultural boundaries. Here we introduce a novel cross-discipline and cross-country activity with the overall goal to expose students to an international environmental problem (climate change) that requires an awareness of different perspectives, so as to contribute to their development of responsible global citizenship through internationalization of the curriculum. Students studying in Australia and the United States of America completed an anonymous survey on their climate change perceptions, and then the students discussed the results via a live video link. The survey results provided the catalyst for students to reflect on the ecological impact of their different lifestyles. The students could demonstrate their critical thinking skills and develop cross disciplinary thinking by exploring the vexed issue of climate change science, perceptions, and culture. Overall, the survey was simple to implement and the tutorial was successful despite the different time zones. Our activity achieved the broader goal of internationalization of student learning and enhanced our students' ability to view problems from different angles and helped foster boundary-crossing skills

A Bayesian network to predict coastal vulnerability to sea level rise

This paper is not subject to U.S. copyright. The definitive version was published in Journal of Geophysical Research 116 (2011): F02009, doi:10.1029/2010JF001891.Sea level rise during the 21st century will have a wide range of effects on coastal environments, human development, and infrastructure in coastal areas. The broad range of complex factors influencing coastal systems contributes to large uncertainties in predicting long-term sea level rise impacts. Here we explore and demonstrate the capabilities of a Bayesian network (BN) to predict long-term shoreline change associated with sea level rise and make quantitative assessments of prediction uncertainty. A BN is used to define relationships between driving forces, geologic constraints, and coastal response for the U.S. Atlantic coast that include observations of local rates of relative sea level rise, wave height, tide range, geomorphic classification, coastal slope, and shoreline change rate. The BN is used to make probabilistic predictions of shoreline retreat in response to different future sea level rise rates. Results demonstrate that the probability of shoreline retreat increases with higher rates of sea level rise. Where more specific information is included, the probability of shoreline change increases in a number of cases, indicating more confident predictions. A hindcast evaluation of the BN indicates that the network correctly predicts 71% of the cases. Evaluation of the results using Brier skill and log likelihood ratio scores indicates that the network provides shoreline change predictions that are better than the prior probability. Shoreline change outcomes indicating stability (−1 1 m/yr) was not well predicted. We find that BNs can assimilate important factors contributing to coastal change in response to sea level rise and can make quantitative, probabilistic predictions that can be applied to coastal management decisions.Funding for this work was provided by the USGS Coastal and Marine Geology and Global Change Research programs

Application and evaluation of shoreline segmentation mapping approaches to assessing response to climate change on the Illawarra Coast, South East Australia

Climate change, particularly sea-level rise, threatens many coastal systems around the world. Coastal managers and decision-makers require information that enables them to assess the vulnerability of the coastlines to the range of impacts and to develop cheap, simple, generic tools, prompting the need to develop tools that can be used to study the impacts of climate change and sea-level rise on the coastal zones. This thesis examines tools that are available to assist in determining sensitivity of the coast, and then describes strengths and weaknesses of three different coastal assessment tools that adopt a GIS (Geographical Information System) approach to assess sensitivity of the shoreline, segmenting it on the basis of different variables. Each tool is applied to one case study section of the coast, the Illawarra region in southern New South Wales, Southeast Australia. The three tools are Dynamic Interactive Vulnerability Assessment (DIVA) tool, Geomorphic Stability Mapping (GSM) approach and the Coastal Sensitivity Index (CSI). The DIVA tool uses a global shoreline database (DINAS-Coast) and can be run using sea-level rise and the socio-economic scenarios in timesteps to the year 2100. The DIVA tool incorporates, socio-economic variables, and provides a vulnerability assessment. The Illawarra coast is represented by a single segment (segment 11105), and the tool is not designed for use at such a fine segment scale. The GSM approach, based on vulnerability mapping of the Tasmanian coast, segments the coast on the basis of form and fabric. It involves a user-defined set of segments that are divided where any of the variables change alongshore. In applying GSM approach to the Illawarra coast, several fields have been redefined and new classes of shoreline landforms identified, of which open ocean sandy shores backed by plains and dunes were scored with the highest sensitivity. After mapping the relative sensitivity of the Illawarra coast on the basis of the GSM approach, a time-series of aerial photographs was used to assess the pattern of historical shoreline change. The Digital Shoreline Analysis System (DSAS) tool was employed to describe rates of shoreline change of the high water line (HWL) and the vegetation line indicators for 11 beaches, and MIKE Marine DHI was used to calculate the subaerial beach and dune sediment volumes from 1938 to 2001 for 3 beaches, in order to determine to what extent modelled sensitivity corresponded with observed patterns of change. Abuodha, P. A. O., 2009 xv Application and Evaluation of Shoreline Segmentation Mapping Approaches in SE Australia This historical reconstruction provided further data from which to derive the CSI, modifying the CVI method that has been used in many developed countries. Where previous assessments have used six or seven variables, this analysis of the Illawarra coast used nine variables, of which six were structural variables (rock type, geomorphology, barrier type, shoreline change, segment exposure, coastal slope), and three were process variables (relative sea-level rise, mean wave height and tidal range). The patterns of change on the Illawarra coast are highly variable, many beaches were found to have accreted when the vegetation line was mapped over time, but different trends and different rates are observed from one beach to another and in some cases within the same beach. Each of the tools involves a level of generalisation, and their application is intended only as a first stage in assessment of shoreline vulnerability. Applying the three tools to the one case study enabled an evaluation of their relative strengths and weaknesses on the basis of several different criteria. The results from this study are useful to decision-makers and local councils in undertaking a more detailed, site-specific assessment for the Illawarra coast in the near future