海面上昇及び高潮の複合効果によるオセアニア小島嶼開発途上国への影響評価：現在及び将来気候による地域人口における脆弱性及び影響に関するケーススタディ

京都大学新制・課程博士博士(工学)甲第23481号工博第4893号新制||工||1764(附属図書館)京都大学大学院工学研究科社会基盤工学専攻(主査)教授 森 信人, 教授 立川 康人, 准教授 志村 智也学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDFA

Impact Assessment of Storm Surge and Climate Change-Enhanced Sea Level Rise on Atoll Nations: A Case Study of the Tarawa Atoll, Kiribati

The Pacific region consists of numerous Small Island Developing States (SIDS), one of the most vulnerable to flooding caused by compound effects of sea level rise (SLR) and storms. Nevertheless, individual studies regarding the impact assessment for SIDS, such as the low-lying Kiribati, remain scarce. This study assessed the impact of climate change-induced storm surge and SLR compounding effects on Tarawa, the most populous atoll of Kiribati, the largest coral atoll nation. It projected the impact using a combined dynamic surge and SLR model based on the IPCC AR5 RCP scenarios and 1/100 and 1/50 years return period storm events. This approach allows estimating the inundation scope and the consecutive exposed population by the end of the 21st century. The results of this study show that the pace of SLR is pivotal for Tarawa, as the sea level rise alone can claim more than 50% of the territory and pose a threat to over 60% of the population under the most intense greenhouse gas emissions scenario. Furthermore, most coasts on the lagoon side are particularly vulnerable. In contrast, the contribution of extreme events is generally minimal due to low wind speeds and the absence of tropical cyclones (TC). Despite this, it is clear the compound effects are critical and may inescapably bring drastic changes to the atoll nations by the end of this century. The impact assessment in this study draws attention to the social impact of climate change on SIDS, most notably atoll islands, and evaluates their adaptation potential

Effects of pre-treatment on Biochemical Methane Potential (BMP) testing using Baltic Sea Fucus vesiculosus feedstock

Seaweeds are considered a viable feedstock for producing energy through the anaerobic digestion conversion process. Its exploitation and use as an alternative renewable energy source; however, remains marginal in the EU. This study aims to evaluate BMP in batch tests of the brown algae Fucus vesiculosus from the Baltic Sea and collected from the Latvian coast. The lab scale BMP tests were oriented towards the evaluation of the effects of mechanical and microwave pre-treatment methods, as well as the impact of a different algae-to-inoculum (A/I) ratio using: i) cutting blades together with mortar and pestle (C&PM) in combination with the use of a 700 W capacity microwave, ii) 1:3 and 1:5 A/I ratios. The cumulative CH4 yields show a value in the range of 68 ± 21 mL CH4/gVS – a trial with no microwave treatment and A/I of 1:3) and 144 ± 28 mL CH4/gVS – a trial including a microwave treatment for 3 min, and A/I ratio of 1:3. The results show effectiveness in the range of 7.8%–43.7%, when the microwave pre-treatment is applied for 1.5 min, and a range of 37.2%–45.2% when the pre-treatment is applied for 3.0 min. The results of this study suggest promising potential for F. vesiculosus for biogas production, especially in the Baltic region